JPS6124187B2 - - Google Patents

Description

Detailed Description of the Invention The present invention is an adhesive molding process in which a resin core material containing a polyolefin thermoplastic resin such as polypropylene is molded into a desired molded product shape, and a skin material is adhered to the surface of the resin core material. Concerning improvements in methods.

For example, in automotive interior materials, resin boards have recently come to be used instead of core materials such as hardboards. As the material of the resin constituting this resin board, for example, a polyolefin thermoplastic resin such as polypropylene is used.

However, when polyolefin thermoplastic resin such as polypropylene is used as a core material, it has been pointed out that when bonding this material and a skin material, it is difficult to adhere due to the difference in polarity between the two. has been done.

Therefore, the conventional method of using a core material made of a polyolefin thermoplastic resin such as polypropylene, bonding it to the skin material, and forming the core material into the desired shape is to use an adhesive agent on the surface of the resin core material. As an agent, a nonwoven fabric made of a material with good adhesiveness to the skin material is pasted in a semi-buried state, and the skin material is pasted to the resin core material through this.

However, in this construction method, the resin core material is plasticized by heating in advance, a skin material is placed on the surface of this material, and the two are fixed together using a press mold, etc. The residual heat of the material is transferred to the skin material, causing, for example, grains formed on the surface of the skin material to be washed away or deterioration of the material quality of the skin material. Furthermore, since the nonwoven fabric is fixed in a semi-embedded state on the surface of the resin core material, the surface of the resin core material is relatively smooth, and air bubbles between it and the skin material during the press bonding molding process are prevented. Easily accumulates and defoaming is difficult. For this reason, air bubbles are formed in a portion of the molded product, causing unevenness.

The present invention has been made in view of the drawbacks of the conventional adhesive molding method, in which a nonwoven fabric is laminated in advance on the skin material side, and heat transfer from the resin core material during the press adhesive molding process is controlled by the nonwoven fabric. Provided is a method for bonding and molding a bonded molded product, which prevents the air from being transmitted to the skin material side by the layer, thereby obtaining good surface properties, and allowing good defoaming due to the surface roughness of the nonwoven fabric. It is something to do. An embodiment of the present invention will be described in detail below with reference to the drawings.

First, as the resin core material used in the present invention, a polyolefin composite resin such as so-called polypropylene, which is made by blending 50 parts by weight of polypropylene with 50 parts by weight of wood flour as a filler, is used.

The core material 1 made of a polyolefin composite resin such as polypropylene is heated in the initial stage of its molding. This heating temperature is approximately 200
℃ or higher. The core material 1 heated in this way is plasticized, and in this plasticized state, the resin core material 1 is molded into a mold surface 2A of a desired shape as shown in FIG. It is installed in the lower mold 2 of the press molding die, and is installed in a state where it conforms to the mold surface 2A due to its plasticization.

Next, after installing the resin core material 1, a skin material 4 made of, for example, vinyl chloride and having a nonwoven fabric 3 laminated in advance on the back side is installed on the surface of the resin core material 1, as shown in FIG. Further, the nonwoven fabric is made of a material such as polypropylene, polyester, or polyamide, and bites into the resin core material 1 during the adhesion process shown in FIG. 3, and its anchoring effect makes the skin material and the resin core material integral. It is designed to be pasted on. Further, this layer of nonwoven fabric 3 is adhered to the skin material 4 to a required thickness, and its surface roughness is extremely large.

Therefore, as shown in FIG. 3, the skin material is the resin core material 1.
When placed on top, a required gap is formed at the joint surface between the two.

After being installed in this way, the upper mold 5 is engaged with the lower mold 2 and clamped.

In this state, the nonwoven fabric 3 bites into the surface side of the resin core material 1 that has been plasticized by the press pressure of the upper die, and the air bubbles that accumulate in the gaps formed between the two are transmitted through the gaps in the nonwoven fabric 3. The gas then moves from the center of the mold to both ends, resulting in good defoaming.

FIG. 4 shows a cross section of the layers of the bonded molded product bonded by the above-mentioned process. 1 and the skin material are well bonded. In addition, the nonwoven fabric 3 has a function as a heat insulating material between the resin core material 1 and the skin material 4, which are heated and plasticized during the adhesive molding process, so that the heat of the resin core material is transferred to the skin material 4. As a result, for example, the grains formed on the surface of the skin material do not flow and can maintain a good grain shape.

In the above embodiments, a composite resin is used as the resin core material, but the present invention is not applicable only to this composite resin, but is also applicable to bonding and molding of a skin material to a single polyolefin thermoplastic resin. Of course, it can also be applied.

As explained above, in the adhesive molding method of a bonded molded product according to the present invention, by laminating the nonwoven fabric on the skin material side in advance as described above, the heated and plasticized resin core material is heated and plasticized. During the adhesion and molding process between the skin material and the skin material, the heat insulating effect of the nonwoven fabric is prevented from transmitting heat to the surface of the skin material. Because there is no grain flow, and the nonwoven fabric maintains a certain degree of surface roughness,
Air bubbles that accumulate between the skin material and the resin core material during the press bonding process are discharged outside the mold through the gaps in the nonwoven fabric, and therefore, unevenness due to air bubble accumulation does not occur, resulting in a good finish. It has advantages such as being able to be molded.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams showing the steps of the present invention, and FIG. 4 is a partially enlarged sectional view of a molded product obtained by each step. 1...Resin core material, 2...Lower mold, 3...Nonwoven fabric, 4...Skin material, 5...Upper mold.

Claims (1)

[Claims] 1 A resin core material containing at least an olefin thermoplastic resin is heated to plasticize it, and the core material is placed in the lower mold of a press molding die, and then a nonwoven fabric is bonded to the back side while maintaining its surface roughness. The prepared skin material is placed on the core material, and then the upper mold is engaged with the lower mold and pressed, thereby expelling the air between the core material and the skin material to the outside of the mold, and discharging the air between the core material and the skin material to the outside of the mold. A method for bonding and molding a bonded molded product, characterized in that a skin material is bonded to the surface of the bonded product, and the product is formed into a desired shape.