JPS6328778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press molding method in which reinforcing metal fittings are integrally embedded in the back surface of the molded body of the rear parcel during press molding of the rear parcel.

A rear parcel is generally made by bonding a skin material directly or via a pad material to the surface of a core material such as hardboard that has been trimmed to the shape of the part.

In addition, heavy objects are often installed on the rear parcel, so the strength of the core material alone is insufficient, so reinforcing metal fittings such as metal channel material or pipe material are installed on the back side of the parcel. Conventionally, this method of attachment involves caulking means such as tacking or riveting, which requires a complicated process, and the tacking marks, rivet heads, or caulking nails may be attached to the core material or surface. It is exposed on the surface of the material and becomes uneven, resulting in a poor appearance of the product.

In particular, the rear parcel has a structure that can be opened and closed in conjunction with the opening and closing of the back door, etc., so the back surface is exposed and the reinforcing metal fittings are exposed, making it look even worse.
There have also been reports of people getting injured by touching the edges of the metal fittings.

On the other hand, if the core material is made of resin, inserting the above-mentioned reinforcing metal fittings at the time of molding will eliminate the complexity of the man-hours described above, and eliminate tacking marks, rivet heads, nails, etc. Since there is no exposure to the surface and no exposure of the reinforcing metal fittings themselves, the appearance is improved and safety can be greatly improved. However, when it comes to reinforcing metal fittings and other insert methods, it is generally customary to use injection molding, etc., but considering that the above-mentioned rear parcel is large and the plate thickness and resin material are also limited, this is not always the case. Not the best method.

By the way, the material chosen for the core material is a polyolefin resin such as polypropylene with a large amount of organic or inorganic filler such as wood flour (pulverized waste wood such as wood chips) in order to make it cheap and strong. However, such resin materials are unsuitable as injection molding materials due to problems such as flow, and press molding is most suitable.

In addition, when inserts are made using the press molding method, the rear parcel itself to be press molded is large, and the reinforcing metal fittings buried inside it are large, so the resin shrinks in the latter half of the molding cycle and the Due to the shrinkage difference especially in the longitudinal direction with the inserted reinforcing metal fittings, the rear parcel molded body is curved along the longitudinal direction of the reinforcing metal fittings, so insert molding of large products is extremely difficult with this press molding method. It was difficult and had not been put into practice.

The present invention has been made in view of the above-mentioned background, and it solves the problems such as warpage caused by the difference in shrinkage during press-forming in the molded body of rear parcels, and integrates reinforcing metal fittings during press-forming. The purpose is to

In order to achieve the above object, the present invention provides a composite resin board containing wood powder that is preheated to near the melting point and whose shape is maintained in that state, and a composite resin board that is placed at an appropriate position on the back surface of the composite resin board. A covering material made of the same or similar material and preheated to near the melting point, and a material having a length approximately equal to the length or width of the composite resin board interposed between the covering material and the composite resin board. Each of these members is positioned and placed in a press mold in order, and the mold is then pressed to form the composite resin plate into the shape of a rear parcel.At the same time, the reinforcing metal Both ends of the reinforcing metal fittings are opened, and both edges of the covering material are fused to the back surface of the rear parcel so as to surround the outer periphery of the reinforcing metal fittings by mold pressure. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows each component of the rear parcel according to the present invention before molding, in which 1 is a composite resin plate, 2 is a composite resin plate;
is a covering material made of a material similar to this composite resin plate 1,
3 and 4 are reinforcing metal fittings interposed between them in the form of a sanderch, and the reinforcing metal fitting 3 is interposed on the back surface of the central part of the resin plate 1 along the longitudinal direction perpendicular to the plane of the paper, and the reinforcing metal fitting 4 is also made of resin. It is arranged to be interposed on the back surface of the edge portion of the plate 1 along its longitudinal direction.

Each of the above-mentioned reinforcing metal fittings 3 and 4 has a hollow pipe shape and a hollow prismatic shape with the same cross-sectional diameter, respectively.
These reinforcing metal fittings 3 and 4 are formed to have a length equal to the length or width of the composite resin plate perpendicular to the plane of the paper.

The composite resin plate 1 is made by adding 50 parts of an organic or inorganic filler such as wood flour to 50 parts of a polyolefin resin such as polypropylene that does not have adhesive properties to the reinforcing metal fittings 3 and 4, and extruding the mixture. The rear parcel is trimmed in advance along the outer shape of the rear parcel to be obtained.

The covering material 2 is made of a material similar to the resin plate 1, such as the same as the composite resin plate 1, or a thermoplastic resin that can be welded to the resin plate 1 during press molding, which will be described later. is trimmed to a width that covers the

The length of the covering material 2 in the longitudinal direction is approximately the same as that of the reinforcing metal fittings 3 and 4, and is formed to such a length that both end surfaces of the reinforcing metal fittings 3 and 4 are exposed at least during molding as described below. .

Next, the order of press forming using each of the above constituent members will be explained using FIGS. 2A to 2C.

The press molding die shown in each figure consists of a lower mold 10 having a rear parcel-shaped mold surface 10a carved thereon, and an upper mold 11 that engages with this lower mold 10. Recesses 12 for positioning the covering material 2 and reinforcing metal fittings 3, 4 are bored.

Before installing each member in the shape of a press molding die, the synthetic resin plate 1 and the composite resin plate 2 are preheated to near their melting points. When the resin plate 1 and the covering material 2 are made of a composite resin based on polypropylene, they are heated to 200°C or higher, which is near the melting point (240°C) of the base material. Due to the filler's function as a binder, it remains semi-fluid but retains its shape.

Next, with both molds 10 and 11 open, the resin plate 1 heated as described above is placed on the mold surface 10a of the lower mold 10, and then the reinforcing material embedding position on the resin plate 1 is placed. The reinforcing metal fittings 3 and 4 are placed on each of the metal fittings 3 and 4, and the covering material 2 is placed on each of the metal fittings 3 and 4 (see Fig. 2B).

Next, as shown in FIG. 2C, the upper mold 11 is attached to the lower mold 10.
When the resin plate 1 is engaged and pressed, the resin plate 1 in a semi-fluid state is press-molded along the shape of the mold, and in this state, heat is rapidly removed by the upper and lower molds 10 and 11, and the resin plate 1 is cooled and solidified.

At the same time, the reinforcing metal fittings 3 and 4 are press-fitted into the resin plate 1 in a semi-embedded state by the engagement pressure, and both edges of the covering material 2 on top of these metal fittings are plastically deformed to form a plastic plate. 1, and since both are in a semi-molten state in this state, they fuse together, resulting in
The upper halves of each of the reinforcing metal fittings 3 and 4 are encapsulated and cooled and solidified in this state. Note that even if the metal fittings 3, 4 and the covering material 2 are slightly shifted from the required positions when positioning each of the above-mentioned members, their positions are corrected along the recessed part 12 of the upper mold 11.

In the second half of this molding cycle, the metal fittings 3, 4 and each resin constituting the molded body contract as they cool, and a shrinkage difference occurs between the metal fittings 3, 4 and the resin. Since both end surfaces of 4 (only one end surface is shown in the figure) are exposed as shown in the figure, the resin shrinks while sliding relative to the metal fittings 3 and 4 in the longitudinal direction. As a result, the linearity of each of the metal fittings 3 and 4 is maintained, and since the resin is guided by the metal fittings 3 and 4 and contracted, the flatness of the non-curved portions is maintained.

After demolding, a molded product is obtained in which reinforcing metal fittings 3 and 4 are integrally embedded in desired positions on the rear surface of the rear parcel, as shown in FIG. 3.

Note that the same molded product can be obtained even if the covering material 2, reinforcing metal fittings 3 and 4, and resin plate 1 are laminated in this order on the lower mold and then press-molded, but in any case, each resin is Because it is easy to lose heat quickly,
It is necessary to perform the work from lamination to mold clamping quickly.

As explained in detail in the embodiments above, since the method for press forming a rear parcel according to the present invention is configured as described above, it is possible to insert metal fittings by press forming, and therefore it is possible to insert metal fittings by press forming. Compared to attaching metal fittings by tucking, riveting, caulking, etc., the man-hours are significantly simplified, and since the metal fittings are supported in their entire longitudinal direction at the bottom of the rear parcel, the installation strength is greater than that of conventional attachment methods. This also has the advantage of improving the mounting strength of the rear parcel itself and improving the appearance of the molded product.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing each component of the rear parcel according to the present invention and their arrangement before molding;
2A to 2C are process explanatory views showing the molding order of the present invention, and FIG. 3 is a partial perspective view of the finished product. 1... Composite resin plate, 2... Covering material, 3, 4...
Reinforcement fittings, 10, 11... Mold (10... Lower mold,
11... upper mold).

Claims (1)

[Scope of Claims] 1. A composite resin board containing wood flour that is preheated to near its melting point and whose shape is maintained in that state, and a material that is the same as or similar to the composite resin board and that is placed at an appropriate position on the back surface of the composite resin board. It consists of a covering material that has been preheated to near its melting point, and a hollow cylindrical reinforcing metal fitting with a length that is approximately equal to the length or width between the covering material and the composite resin plate, and each of these members is placed in a press molding die. Afterwards, the mold is pressed to form the composite resin plate into a rear parcel shape, and at the same time, both ends of the reinforcing metal fittings are opened, and the covering material is reinforced by mold pressure. A press-molding method for a rear parcel for an automobile, characterized in that both edges of the metal fittings are fused to the rear surface of the rear parcel so as to surround the outer periphery of the metal fittings.