JPH0272915A - Manufacture of molding made of synthetic resin - Google Patents

Abstract

PURPOSE:To constitute the title method so that neither a decorative part is caused to deviate through pressure of resin at the time of injection molding nor a main body resin layer on a surface side is forced out on the surface of the decorative part, by a method wherein the decorative part is combined with a recessed part formed in a shape retaining core material by fitting the decorative part in the recessed part, which is cut into fixed lengths and charged into an injection mold. CONSTITUTION:A decorative part 2 is extrusion-molded beforehand, a main body resin layer 12a of the backside of a molding main body 1 is extrusion-molded unitarily with a shape retaining core material through a comparatively soft synthetic resin and they are combined with each other. The combined goods cut into fixed lengths are charged into injection molds 55a, 55b and a surface side main body resin layer 12b is injection-molded under a state where the surface of the decorative part 2 is stuck to the inside of a cavity of the injection mold through elasticity of the main body resin layer 12a of the backside. With this construction, the main body resin layer 12b can be injection-molded easily on the surface side of a shape retaining core material 11 under a state where the decorative part 2 is held through close adhesion on the inside of the cavity of the injection mold through the elasticity of the soft main body resin layer 12a formed beforehand on the backside of the shape retaining core material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a synthetic resin molding that is attached to the side surface of a vehicle body, for example, or the peripheral edge of a window glass.

[Conventional technology]

Recently, many types of moldings have been used in which a decorative part having a transparent or semi-transparent resin layer is provided on the surface of the molding body to create a soft striped decorative pattern. .

For example, as shown in FIG. 6(a), the above-mentioned molding
- As shown in (b), a glittering metal thin plate is placed on the surface of the molding body 1, which is formed by extruding a body resin layer 12 such as colored soft vinyl chloride resin on the entire circumferential surface of a shape-retaining core material 11 made of metal etc. Or a decorative base material 21 such as colored resin and 2
It is known to have a decorative part 2 formed by bottling a liquid-curable polyurethane resin or the like to a constant thickness using surface tension and curing it by reaction to form a lens-shaped transparent or translucent see-through resin N22. However, unless the portion where the transparent resin layer 22 is formed is horizontal, the above-mentioned pointer cannot be formed, and the thickness of the transparent resin layer is also limited, so there are restrictions on the cross-sectional shape of the molding, etc.

For example, as shown in FIG. 7, a thermoplastic resin such as polymethyl methacrylate resin (hereinafter abbreviated as PMMA resin) is used as the transparent resin N22, and the main body resin layer 12 made of soft vinyl chloride resin etc. Transparent resin layer 2
2 and 2 on the circumferential surface of the shape-retaining core material 11 made of a glittering metal plate, the molding temperature of the soft vinyl chloride resin forming the main body resin layer 12 (approximately 150 to I
PMMA forming the transparent resin layer 22 compared to 50"C)
Since the molding temperature of the resin is high (approximately 230 to 240° C.), there is a problem that the gloss of the portion of the main resin layer 12 close to the see-through resin layer 22 becomes extremely high, causing unevenness.

Furthermore, as shown in FIG. 8(a)/0)), a molding body 1 is formed by coating a body resin layer 12 on the surface of a shape-retaining core material II, and a decorative base material 21 such as a glittering metal thin plate. The decorative portion 2 whose surface is covered with a transparent resin layer 22 is formed separately by extrusion molding to form a double-sided adhesive tape T.
Although a method of fixing the resin layer 12 and the transparent resin layer 22 on the surface of the molding is known, a depression g is inevitably formed between the main resin layer 12 and the transparent resin layer 22, which impairs the sense of unity and gives a poor appearance.

Also, in any of the above cases, conventionally the molding body 1
is formed by extrusion molding, and both longitudinal ends 1a and 1 are formed by extrusion molding.
A is made of the same material as the main body resin layer described above.

6(a) and 8 by injection molding with resin.
Although the entire treatment is performed as shown in Figure (a), there are cases where sushi-like marks remain between the resin layer and the surface gloss due to the difference in the molding method between extrusion molding and injection molding. There was a problem that caused the appearance to deteriorate.

Therefore, the decoration part 2 having the transparent resin layer 22 is formed in advance by extrusion molding, and it is inserted into an injection mold together with the shape-retaining core material 11, so that the entire main body resin layer including the edge treatment part is formed. However, it has been difficult to position and hold the extrusion molded product at a predetermined position within the injection mold. In addition, the above-mentioned extrusion molded products do not necessarily have good dimensional accuracy, so it is difficult to make the extrusion molded products adhere well to the inner surface of the cavity of the injection mold. Even if a part of the extrusion molded product is formed separately and the extrusion molded product is pressed against the inner surface of the cavity from the back side using a spring or the like, manufacturing errors of the extrusion molded product cannot be fully absorbed, and the injection molding There were problems such as the mold structure becoming complicated.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned problems, and is a molding comprising a decorative portion having a see-through resin layer on the surface of a molding body formed by covering the peripheral surface of a shape-retaining core material with a body resin layer. To provide a method for manufacturing a synthetic resin molding which can be easily manufactured and which can finish the surface of the main body resin layer including both ends in the longitudinal direction smoothly and with good appearance.

[Means to solve the problem]

The present invention manufactures a synthetic resin molding in which a decorative part having a transparent or translucent see-through resin layer is provided on the surface side of a molding body made by covering the peripheral surface of a shape-retaining core material with a body resin layer. In doing so, the decorative portion is extruded in advance, and the main body resin layer on the back side of the molding body is extruded from a relatively soft synthetic resin together with the shape-retaining core material to form the shape-retaining core material. The decorative parts are fitted into the four parts, and the combined product is cut to a predetermined length and loaded into an injection mold, and the surface of the decorative part is molded by the injection molding using the elasticity of the main body resin layer on the back side. The gist of the present invention is a method for manufacturing a synthetic resin molding, which is characterized by injection molding the main body resin layer on the front side while being in close contact with the inner surface of the cavity of the mold.

[Function] A decorative part having a transparent resin layer and a main body resin layer coated on the back side of the shape-retaining core material are each continuously formed by extrusion molding, and the shape-retaining core material is formed on the shape-retaining core material. By fitting the decorative part into the recess and combining it, cutting it to a predetermined length and loading it into the injection mold, the decorative part fits into the predetermined part of the injection mold through the shape-retaining core material. At the same time, the elasticity of the relatively soft main body resin layer on the surface side allows the surface of the decorative portion to be held in close contact with the inner surface of the cavity of the injection mold with appropriate pressure. Become. Therefore, by injection molding the front body resin layer in this state, the decorative part may shift due to the pressure of the resin during injection molding, or the front body resin layer may protrude onto the surface of the decorative part. It is possible to form moldings without any problems.

Furthermore, the injection molding described above makes it possible to finish the entire main body resin layer on the front surface side smoothly, including both ends in the longitudinal direction of the molding.

〔Example〕

The present invention will be explained below using as an example a side molding attached to the side surface of an automobile body shown in FIGS. 1 and 2.

Although the illustrated molding body 1 is composed of a shape-retaining core material 11 made of a galvanized steel plate and a main body resin layer 12 made of a relatively soft vinyl chloride resin, other materials may be used.

The decorative part 2 is made up of a decorative base material 21 and a transparent resin layer 22, and a bright metal thin plate such as stainless steel or aluminum is used as the decorative base material 21, and PMMA resin is used as the transparent resin N22 on the entire circumference of the decorative base material 21. It has a structure covered with layers. However, the material and structure of the decorative portion 2 may be determined as appropriate. For example, the decorative base material 21 may be made of plastic colored in a desired color.
Using MMA or ABS resin, one side (outer surface)
A transparent or translucent PMMA resin layer may be coated as a see-through resin layer.

In manufacturing the synthetic resin molding as described above, in the present invention, the decorative portion 2 is extruded in advance, and the main resin layer 12a on the back side of the molding main body 1 is shaped with a relatively soft synthetic resin. Core material 11
The combined product is cut into a predetermined length and loaded into an injection mold, and the elasticity of the main body resin layer 12a on the back side allows the surface of the decorative part to be molded as described above. The main body resin layer 12b on the front side is injection molded in close contact with the inner surface of the cavity of the injection mold.
An example of the manufacturing method will be specifically explained below based on FIG. 3.

FIG. 3 shows an apparatus for manufacturing the molding shown in FIGS. 1 and 2, in which the peripheral surface of a decorative base material 21 made of a glittering metal thin plate as described above is coated with a transparent resin layer 22 as a decorative part 2. This shows a configuration example, and the decorative base material 21 is sequentially fed out from a supply roll 31.

The decorative base material 21 is then roll-formed into a predetermined cross-sectional shape by a roll forming machine 32, and a draining device 33
Water droplets etc. are removed. Then, a hot-melt adhesive such as acrylic adhesive for properly fixing the transparent resin layer 22 is applied to substantially the entire circumference of the decorative base material 21 using a coating bag W34, and high-frequency baking is performed using a device 35. .

Next, the decorative base material 21 is fed into a first extrusion molding process [36] to coat the peripheral surface of the decorative base material 21 with transparent resin 22.
It is formed by extrusion molding of MA resin, is cooled and solidified in a cooling water tank 37, and then drained and dried in a draining and drying device 38 to form the decorative portion 2 shown in FIG. 4(a).

In this case, the transparent resin layer 22 is attached to the decorative base material 21 as shown in the figure.
It is also possible to form it on the back side. It is decorative base material 21
If a resin layer is not also formed on the back side of the decorative base material 21, the decorative base material 21 made of a thin metal plate will rub against the mold due to the pressure of the resin when extruding the resin layer on the front side, causing the decorative base material 21 to become smooth. Movement is obstructed, and the support for the decorative base material made of copper alloy on the mold side wears out and must be replaced frequently. This is because the resistance during extrusion molding can be reduced.

Further, the roll forming of the decorative base material 21 as described above is mainly performed by forming both side edges of the decorative base material 21 as shown in FIG. 4 (a).
) This is to prevent both end faces from being seen from the front side by bending it towards the back side.

Note that the decorative portion 2 is made of PMMA colored as described above.
Alternatively, in the case of a decorative base material made of ABS resin and a see-through resin layer made of transparent or translucent PMMA resin, extrusion can be easily performed by feeding each of the above resins into the same extrusion mold. Can be molded.

On the other hand, the shape-retaining metal core material 11 is sequentially fed out from the supply roll 41 and roll-formed! At step 42, the sheet is roll-formed into a predetermined cross-sectional shape, and at drainer 43, water droplets and the like are removed. Then, a hot melt adhesive such as a phenolic adhesive is applied to the back surface of the shape-retaining core material 11 by a coating device 44 in order to properly fix the main body resin layer 12, and baking is carried out by a device 44.
In step 5, high frequency baking is performed.

Next, the shape-retaining core material 11 is fed into the second extrusion molding machine 46, and the main body resin 71 is applied to the back surface of the shape-retaining core material 11.
The main body resin layer 12a on the back side forming a part of the resin layer 12 is formed by extrusion molding of vinyl chloride resin, and after being cooled and solidified in a cooling water tank 47, it is drained and dried in a draining and drying device 48, as shown in FIG. 4(b). The molded article shown is formed.

Subsequently, the molded product is sequentially combined with the decorative part 2 by a combination guide roller 51 as shown in FIG. 4(C) 9
In the case of the figure, a concave part 1 in which a decorative part 2 is formed in a shape-retaining core material 11
By narrowing the upper side of the concave portion 11a, the decorative portion 2 may fall off inadvertently after being combined, and when the main body resin layer on the front side is injection molded, which will be described later, in the width direction. It is designed to stay in place.

The molded product combined as described above is then cut into a cutting machine 5.
2, it is cut to a predetermined length. And the above recess 11a
A hot melt adhesive such as a phenolic adhesive similar to that described above is applied to the surface side of the shape-retaining core material 11 with the coating device 53, and is baked in the device 54, followed by injection molding machine 5.
It is loaded into the mold 5.

The mold is a movable upper mold 55a as shown in FIG.
and a fixed lower mold 55b5 and an insert holder 5 which also serves as an ejector and is movable up and down with respect to the lower mold 55b.
5c, the shape-retaining core material 11 is held at a predetermined position in the cavity by the insert holder 55c, and the elasticity of the soft main body resin layer 12a formed on the back surface of the shape-retaining core material 11 allows the decoration to be carried out. The portion 2 is tightly held on the inner surface of the cavity of the upper die 55a with appropriate pressure, regardless of manufacturing errors or the like. In particular, in the illustrated example, the main body resin N 12 a on the back surface of the recess 11a that accommodates the decorative portion 2
The decorative portion 2 can be held in close contact with the inner surface of the upper mold cavity.

Then, in this state, the main resin layer 2b made of vinyl chloride resin is injection molded on the surface side of the shape-retaining core material 11, and is cooled and solidified to form the synthetic resin molding shown in FIG. 4(e). It is something.

As described above, according to the present invention, the soft main body resin [12a] formed in advance on the back surface of the shape-retaining core material 11 holds the decorative part 2 in close contact with the inner surface of the cavity under moderate pressure due to the elasticity of the soft main body resin [12a]. Since the main body resin layer 12b can be injection molded on the surface side of the core material 11, the decorative part 2 may be damaged due to excessive pressure of the injection molds 55a and 55b, or the adhesion of the decorative part to the inner surface of the cavity may be insufficient. Thus, a part of the main resin layer 12 does not protrude onto the surface of the decorative part 2, and the molding can be performed satisfactorily. Moreover, both longitudinal edges 1 of the molding
By injection molding the entire main body resin layer on the front side including a-1a, the surface can be finished to have a smooth surface as shown in FIG.

In addition, especially when using core materials such as galvanized steel sheets, which are inexpensive but relatively easy to rust, as shape-retaining core materials,
It is desirable to cover the entire circumferential surface of the core material with resin, and in that case, it is conceivable to injection mold the entire resin layer, including both ends of the molding, at the same time. This is not possible because it must be held at the spatial position of In contrast, in the present invention, the main body resin layer 12a on the back side is extruded integrally with the shape-retaining core material in advance, and the main body resin layer 12b on the front side is injection-molded later. The resin layer can be easily coated on the entire circumferential surface.

Since the main body resin layer 12b on the front side and the main body resin layer 12a on the back side are made of the same material, their interfaces are well adhered and integrated, and the main body resin layer 12 (12b) and the transparent resin layer 12a are made of the same material. In this example, the layer 22 uses resins that are compatible with each other, so that the layers 22 are integrated with good adhesion.

Note that the decorative portion 2 can be formed by injection molding instead of extrusion molding, but when injection molding is used, the decorative portion is long, so the mold becomes large and expensive, and the molding efficiency is poor. If an acrylic resin is used, which has poor fluidity because it is thin and long, it will not flow easily and warp or twist easily, and it will not have rigidity and will easily twist when released from the mold. On the other hand, extrusion molding as in the present invention has the advantage that a long decorative part can be easily and continuously molded, and a decorative base material such as a glittering metal thin plate can be easily inserted.

Further, the surface shape of the decorative part etc. may be determined as appropriate. For example, if the transparent resin layer 22 is formed into a lens shape as shown in FIG. It is possible to give a three-dimensional effect to patterns, etc.

(Effects of the Invention) As explained above, the present invention provides a transparent or translucent see-through resin layer 22 on the surface side of the molding body, which is formed by covering the peripheral surface of the shape-retaining core material 11 with the body resin layer 12. In manufacturing a synthetic resin molding with a decorative part 2 having a shape, the decorative part 2 is extruded in advance, and the main resin layer 12a on the back side of the molding main body 1 is made of a relatively soft synthetic resin for shape retention. The core material is extruded and combined, and the combined product is cut into a predetermined length and loaded into the injection molds 55a and 55b, and decorated using the elasticity of the main body resin layer 12a on the back side. Since the main body resin ji12b on the front side is injection molded with the surface of the part 2 in close contact with the inner surface of the cavity of the injection mold, the elasticity of the soft main resin layer 12a formed in advance on the back side of the shape-retaining core material The main body resin layer 12b is placed on the surface side of the shape-retaining core material II while the decorative portion 2 is held in close contact with the inner surface of the cavity of the injection mold.
can be easily injection molded.

In addition, since the entire surface-side main resin layer 12 including the fully processed parts at both longitudinal ends 1a and 1a of the molding can be injection molded at the same time, unlike the case where both ends of the molding are later edge-processed in the conventional example, There are effects such as the ability to easily and inexpensively mass-produce moldings with good appearance without leaving sushi-like marks between the main body resin layer on the surface side and the general processing section.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a synthetic resin molding according to the present invention, FIG. 2 is an enlarged cross-sectional view thereof, FIG. 3 is an explanatory diagram showing an example of a manufacturing apparatus implementing the present invention, and FIG. )~
(e) is an explanatory diagram of the manufacturing process, FIG. 5 is a cross-sectional view of another example of a synthetic resin molding, FIG. 6 (a) and Q)) are a perspective view and a cross-sectional view of a conventional molding, Figure 7 is a cross-sectional view of a molding in another conventional example;
Figure (a) is a perspective view and a cross-sectional view of a molding in still another conventional example. 1 is a molding main body, 11 is a shape-retaining core material, 12 is a main body resin layer, 2 is a decorative portion, 21 is a decorative base material, and 22 is a transparent resin layer.

Claims (1)

[Claims] (1) Manufacture a synthetic resin molding in which a decorative portion having a transparent or translucent see-through resin layer is provided on the surface side of the molding body, which is formed by covering the peripheral surface of a shape-retaining core material with a body resin layer. At the same time, the decorative portion was extruded in advance, and the main body resin layer on the back side of the molding body was extruded from a relatively soft synthetic resin together with the shape-retaining core material, and formed into the shape-retaining core material. The decorative portion is fitted into the recess and combined, the combined product is cut to a predetermined length and loaded into an injection mold, and the surface of the decorative portion is molded into the injection mold due to the elasticity of the main body resin layer on the back side. A method for manufacturing a synthetic resin molding, characterized by injection molding a main body resin layer on the front side in close contact with the inner surface of a cavity.