JPH0355187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing decorative moldings, particularly decorative moldings mainly made of plastics.

Long, thin string-like decorative strips are used on the surfaces of side panels of automobiles, on window frames, on the edges of parts, on the edges of furniture, etc. This type of strip is not only used for decoration, but also has the function of absorbing shock when it comes into contact with the object and protecting the other object.For this reason, strips made of similar plastics are often used. It is being

Incidentally, in recent years, as one type of decorative molding made of plastics, one in which the upper surface of a base strip obtained by extrusion molding or the like is coated with liquid plastic and then cured and integrated has been proposed. ing. However, when a long plastic molding is obtained by coating with this liquid plastic, irregular waving or meandering lines appear in the longitudinal direction of the joint between the liquid plastic and the bulging portion of the base strip. However, it had some defects that seriously impaired its decorative qualities.

In particular, when an extrusion molded product, which is often used in this type of molding, is used as the base strip, the strip surface is exposed to the limits of machining accuracy on the inner surface of the die and the sudden pressure immediately after extrusion from the die into the air. The appearance of these irregular lines was conspicuous because of the presence of fine irregularities due to variations in physical properties such as viscoelasticity of the molten plastic.

The present invention was proposed in view of the current situation, and its purpose is to create beautiful moldings with excellent decorative properties, particularly to create beautiful glossy plastic moldings on the upper surface of the base strip. The object of the present invention is to provide a method of obtaining a molding of a novel concept in which decorative protrusions are formed extremely tightly.

Another object of the present invention is to provide a method that can easily, reliably, and efficiently obtain moldings with excellent decorative properties as described above.

In order to achieve the above object, the present invention provides a decorative protrusion-forming surface on a base strip through a concave groove portion continuous in the longitudinal direction, and pours thermosetting liquid plastic onto the decorative protrusion-forming surface. The object of the present invention is to form a liquid plastic surface by spreading the liquid plastic, and then heat and harden the surface to integrally form a plastic decorative protrusion on the upper surface of the base strip.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below along with embodiments with reference to the accompanying drawings.

FIG. 1 of the accompanying drawings is a partial perspective view showing a decorative molding obtained by the present invention, particularly a protective molding to be attached to a side panel of an automobile, together with its cross section, in which a single groove is formed. Figure 2 is a partial perspective view of another example with its cross section, and Figure 3 is a partial perspective view of another example with its cross section, with two grooves formed on both sides. 4 is a cross-sectional view schematically showing the extrusion molding process of the base strip, FIG. 5 is a cross-sectional view of the base strip extruded in the above process, and FIG. 6 is the surface of the base strip. FIG. 7 is a cross-sectional view showing the state in which the liquid plastic is flowed down the surface of the base strip, and FIG. FIG. 9 is a cross-sectional view showing a state in which the surface is heated and hardened, and FIG. 9 is a cross-sectional view of a molding obtained by a conventional manufacturing method.

As illustrated in FIGS. 1 to 3, decorative molding 1 obtained by the method of the present invention
0, 10A or 10B is composed of a base strip 11 made of extruded plastic or the like, and a decorative protrusion 20 made of a hardened surface of thermosetting plastic formed on the upper surface of the base strip. In particular, the bulge 12 of the base strip 11,
The decorative protrusion forming surface 15 adjacent to the groove 1
6, 17 by forming said surface 1
The decorative protrusions 20 on the top 5 have a beautiful molding in which the edges in the longitudinal direction are tied together.

Next, the manufacturing method of the present invention will be explained using the molding 10 shown in FIG. 1 as an example with reference to FIG. 4 and the subsequent drawings.

First, FIG. 4 shows the known extrusion method as the most efficient and economical means of obtaining the base strip 11.

In the figure, numeral 30 is an extruder, 31 is a die,
32 is a cooling water tank, 33 is a take-up roller, and 34 is a cutter.

As the material of the base strip 11, appropriate extrusion moldable plastics such as polyvinyl chloride resin, ABS resin, polyamide resin, polycarbonate resin, etc. are used. The base strip 11 is colored to enhance its decorative effect, or a decorative surface such as aluminum foil is integrally formed on its surface (not shown).

In this invention, the decorative protrusion forming surface 15 of the base strip 11 has a concave groove portion 16 ( or 17). This concave groove portion 16 (or 17; the same applies hereinafter) is formed by a liquid plastic 21, which will be described later.
During casting, the surface tension of the liquid causes the liquid to stop flowing in the area, forming rounded edges. Therefore, if the width and addition of the groove portion 16 is about 1 mm, it will be sufficient to have this effect.

Note that, depending on the shape of the base strip 11 or the shape of the decorative protrusion 20, the concave groove portion may be one groove like the reference numeral 16 in FIG. Only one side of 15, and even the third
Decorative ridges can be formed on both sides of the decorative ridge-forming surface 15, as shown at 16 and 17 in the figure.

Although it goes without saying that the other shapes of the base strip 11 can be arbitrary, it is preferable that the edges of the decorative ridge-forming surface 15 have a sharp edge such as the right-angled edge 19 shown. This is preferable for the casting of the liquid. The same applies to the groove portion 16 described above.

Next, the thermosetting liquid plastic 21 is flowed out from the nozzle 22 or the like and cast onto the decorative strip forming surface 15 of the base strip 11. The liquid plastic 21 is cast using the natural flow of the liquid and its surface tension.

Due to the casting of the liquid plastic 21 and the surface tension, a liquid plastic surface 22 is formed on the decorative ridge forming surface 15 as shown in FIG. The liquid plastic surface 22 has a so-called lens-like beautiful surface having an extremely smooth mirror-like surface with beautiful rounded edges 25 raised by surface tension at the groove portion 16 and other edges. It is the surface.

If the decorative protrusion-forming surface 15 is a matte surface having fine irregularities formed by extrusion molding, for example, the liquid plastic surface 22 is applied to the fine irregularities as if wetting a ground glass surface with water. Wet and smooth the surface to create a glossy surface.

The liquid plastic 21 used here is a thermosetting one, and a preferred material is, for example, a liquid polyurethane composition comprising a polyol and a diisocyanate. These include appropriate catalysts for the purpose of accelerating or controlling the curing rate, and antioxidants, ultraviolet absorbers, and light stabilizers for the purpose of improving physical properties such as heat resistance, light resistance, or weather resistance of molded products. These adjuvants may be mixed in appropriate amounts.

Other useful liquid plastics include liquid acrylic resin compositions containing methyl methacrylate as a main component and epoxy resin compositions having epoxy groups in their molecules. Note that the liquid plastic may be colored and made transparent by mixing a dye or the like.

After forming the liquid plastic surface 22,
The liquid plastic is heated and hardened to form a plastic decorative ridge 20 integrally on the upper surface 15 of the base strip.

This heat curing step may be performed by irradiating infrared rays with an infrared lamp 29 as shown in FIG. 7, or may be introduced into a heating furnace. The heating temperature is
Depending on the material and physical properties of the liquid plastic,
The temperature will be approximately 50-80℃.

FIG. 9 is a cross-sectional view showing a molding obtained by a conventional manufacturing method for comparison with the present invention, in which the decorative protrusion forming surface 15 of the base strip 11 is formed through a concave groove. If not, as shown in the figure, the decorative protrusions 20 and the bulges 12 of the base protrusions 11,
At the joints 26 and 27 with 13, undesirable decorative lines such as waving and meandering appear, which greatly reduces the commercial value of the molding.

As illustrated and explained above, according to the method for manufacturing a decorative molding of the present invention, the decorative protrusion forming surface of the base strip is provided through the longitudinally continuous concave groove portion, and the decorative protruding forming surface is The method is characterized in that a thermosetting liquid plastic is cast to form a liquid plastic surface, and then this is heated and cured to integrally form plastic decorative protrusions on the upper surface of the base strip. Because it is a product, it has a beautiful molding with excellent decorative properties, that is, a glossy plastic decorative ridge with rounded edges in the longitudinal direction of the groove-formed part of the base strip. A completely new concept of molding has now been obtained which is sharply formed and at the same time has a contrast with the bulge surface portion of the base strip itself.

Furthermore, as described above, this invention can form beautiful decorative ridges by simply forming grooves and casting liquid plastic on the surface on which decorative ridges are formed, utilizing the physical property of liquid surface tension. Therefore, it was possible to provide a simple, reliable, and efficient manufacturing method.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view showing a cross section of a decorative molding obtained by the present invention, particularly a protective molding to be attached to a side panel of an automobile, in which a single concave groove is formed. , Figure 2 is a partial perspective view of another example along with its cross section, and Figure 3 is a partial perspective view of another example along with its cross section, with two grooves formed on both sides. , FIG. 4 is a cross-sectional view schematically showing the extrusion molding process of the base strip, FIG. 5 is a cross-sectional view of the base strip extruded in the above process, and FIG. 7 is a cross-sectional view showing the liquid plastic flowing down the base strip surface, and a liquid plastic surface is formed. FIG. 8 is a sectional view showing the liquid plastic surface being heated. FIG. 9 is a cross-sectional view of a molding obtained by a conventional manufacturing method. 10, 10A, 10B...protective molding for automobiles, 11...base strip, 12,13...bulge portion, 15...decorative protrusion forming surface, 16,17...
... Concave groove portion, 19 ... Right-angled edge, 20 ... Decorative protrusion, 21 ... Liquid plastic, 22 ... Liquid plastic surface, 22 ... Orifice, 29
...Infrared lamp, 30...Extruder, 31...Die.

Claims (1)

[Scope of Claims] 1. A decorative protrusion-forming surface on a base strip is provided via a concave groove portion continuous in the longitudinal direction, and a thermosetting liquid plastic is cast on the decorative protrusion-forming surface to form a liquid plastic. A method for producing a decorative molding, which comprises forming a surface and then heating and curing the surface to integrally form plastic decorative protrusions on the upper surface of the base strip. 2. The method for manufacturing a decorative molding according to claim 1, wherein the grooves are provided on both sides of the surface on which the decorative protrusions are formed.