JPS647865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing foam boards used for flooring, etc., and more specifically, two foam resin boards 4, 4 immediately after being extruded from an extrusion molding machine are placed in a mold 5 with a gap between them. , and then insert two foamed resin plates 4,
4 is foamed in a mold 5 and filled into the mold 5.

Base materials used for flooring and the like are required to have various strengths as shown in FIG. 1 for their performance. Arrows 1 and 1' are the bending strength of the base material 6 against the load,
Further, arrows 2 and 2' indicate the compressive strength of the tongue portion of the base material 6. As a method for manufacturing such a base material 6, a method using a foamed resin has conventionally been used. In other words, when foaming resin is foamed by injection molding, etc., only the surface layer is cooled to suppress foaming of the surface layer, and the central part is particularly foamed to a high degree, thereby reducing the weight and cost of the base material 6. The surface layer has low foaming to give it strength. However, with the above method, there are problems in that the surface cooling conditions when foaming the foamed resin are difficult, and it is difficult to adjust the amount of the blowing agent added to the foamed resin. The problem with the base material 6 was that the difference in expansion ratio between the surface layer and the center portion was small, and the strength of the base material 6 was also weak.

The present invention has been made in view of the above points, and provides a method for manufacturing a foamed board that improves the strength of the foamed board that is the base material, and that is easy to manufacture without the need for adjusting the foaming agent or cooling conditions. The purpose is to

The present invention will be explained in detail below with reference to Examples.

The foam board 7 is manufactured as follows. First, two foamed resin plates 4, 4, which have just been extruded from an extrusion molding machine by curving one side into a circle as shown in Fig. 3, are placed in a closed mold 5 as shown in Fig. 4 with a gap formed. Insert them facing each other. The foamed resin board 4 has started to foam slightly in the extrusion molding machine, but when it is inserted into the mold 5, it rapidly foams due to the heat of the mold 5. The upper foamed resin board 4 and the lower foamed resin board 4 start foaming at the same time, but since foaming is suppressed by the inner wall of the mold 5 when each foams, the inner wall side of the mold 5 The foaming ratio becomes lower, resulting in low foaming layer 1.
It forms the Further, as shown in FIG. 5, the upper and lower foamed resin plates 4, 4 are also foamed toward the hollow part 9, but the foamed layer 1 of the upper and lower foamed resin plates 4, 4
0 and 10 are combined as shown in Figure 5b, the respective foam layers 10 and 10 are compressed and the foaming ratio of the combined portion is low because the foaming of each layer is suppressed, resulting in a low foam layer in the middle part. 2. The low-foam layers 1 and 2 are made of densely cured foam resin, so they are hard and have high bending strength.By being formed on the outer periphery of the foam board, they increase the strength of the foam board, and are also effective when the foam board is nailed. can increase the holding power of nails.

As described above, in the present invention, two foamed resin plates immediately after being extruded from an extrusion molding machine are inserted into a mold with a gap between them, and then the two foamed resin plates are foamed in the mold. Since the foamed resin plate is filled into the mold with the mold, the foaming of the foamed resin plate is suppressed by the inner peripheral wall of the mold, and the foam layer near the inner peripheral wall becomes denser, making it possible to form a low-foam layer on the outer periphery. In addition, when the two foamed resin plates are foamed, the compressive force caused by the foaming of the foaming diffusion surfaces suppresses the foaming of the foaming diffusion surfaces, and this foaming layer becomes denser, making the low foaming layer in the middle part The upper surface, lower surface, both left and right sides, and the middle part of the interior have low foaming, and are sufficient to withstand bending loads from the top and bottom and compressive loads from the left and right, without adjusting the foaming agent or cooling conditions. The advantage is that foam boards can be produced that are durable and suitable for use as flooring and the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a conventional base material, Fig. 2 is a cross-sectional view of a foam board obtained by the method of the present invention, and Fig. 3 is a cross-sectional view of the same two foam resin boards as above extruded from an extrusion molding machine. Figure 4 is a cross-sectional view showing the state in which the two foamed resin plates above are inserted into the mold, Figures 5a and b are the directions of foaming in the method for manufacturing the same foamed board. FIG. 1 and 2 are low foaming layers, 3 is a high foaming layer, 4 is a foamed resin board, and 5 is a mold.

Claims (1)

[Claims] 1. Insert the two foamed resin plates immediately after extrusion from the extrusion molding machine into the mold with a gap between them, and then foam the two foamed resin plates in the mold to fill the mold. A method for manufacturing foam board characterized by: