JPS6365489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a construction board, in which a urethane resin is applied between a lower mold 1 for molding the front surface part and an upper mold 3 for molding the back part having grooves 2 on the inner surface. A foamable synthetic resin 4 such as the above is injected and foam-molded, and then a part of the protrusion 6 formed in the groove 2 of the upper mold 3 is cut off on the back surface of the foamed synthetic resin molded product 5. The present invention relates to a manufacturing method of a characteristic architectural board.

Conventionally, in manufacturing architectural boards made of urethane resin foam, as shown in FIG. Place the upper mold 3' on the upper mold 3', inject urethane resin 4' between the lower mold 1' and the upper mold 3',
Manufactured by heating and foaming. However, air voids are generated on the back surface due to gas or air generated during foaming. In addition, the foaming pressure pushes up the upper mold 3', making it impossible to obtain a uniform thickness.
In order to keep the thickness constant, the thickness is adjusted using a sander or the like during post-processing, but in this case there were problems such as the skin layer disappearing and causing warping.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to allow air and gas generated during foaming to be removed through the grooves of the upper mold, and to reduce the occurrence of air voids. To provide a method for manufacturing a building board, which can reduce warpage of the formed building board.

The present invention will be explained in detail below with reference to Examples. Reference numeral 1 denotes a lower mold for molding the surface portion, and a pattern molding portion is provided on the inner surface, and a silicone rubber mold 7 is installed inside along the inner surface. 3 is an upper mold for molding the back side,
As shown in FIG. 3, grooves 2 are formed on the inner surface in the form of a grid, for example. Then, the upper mold 3 is placed on the lower mold 1, and as shown in FIG. 2, a foamable synthetic resin 4 such as urethane resin is injected into the inside and heated and foamed. Then, a protrusion 6 is formed by the groove 2 on the back surface of the foamed synthetic resin molded product 5. After taking out the foamed synthetic resin molded product 5 with this protrusion 6 from the upper mold 3 and lower mold 1,
A construction board is manufactured by sanding the upper surface of the protrusion 6 to adjust the thickness (the part shown by crosshatching in FIG. 4).

Since the present invention is manufactured as described above, air and gas generated during foaming can be vented and dispersed by the concave grooves of the upper mold, thereby reducing the generation of air voids and reducing the size of the remaining air voids. This improves the appearance, and if the surface pattern of the molded product is markedly uneven, warping will occur due to the difference in surface area between the front and back sides. It is possible to prevent warping during molding by making the surface area close to the surface area of the mold, and since the protrusion on the back side is sanded, it is possible to reliably remove air voids etc. that remain clustered on the upper surface of the protrusion. Furthermore, when the thickness is adjusted by sanding the protrusions on the back surface, there is less of the skin layer on the back surface being scraped off, which prevents warping that would otherwise occur due to the lack of a skin layer. The concave grooves give the back surface of the molded product a rib shape, which has the advantage of improving strength.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional example, FIG. 2 is a sectional view of an embodiment of the present invention, and FIG. 3 is a perspective view of the same upper mold.
FIG. 4 is an explanatory diagram of the state in which the protrusions are shaved, and 1 is the lower mold, 2 is the groove, 3 is the upper mold, 4 is the foamed synthetic resin, 5 is the foamed synthetic resin molded product, and 6 is the protrusion. It is.

Claims (1)

[Claims] 1. A foamable synthetic resin such as urethane resin is injected between a lower mold for molding the front surface part and an upper mold for molding the back part with grooves on the inner surface, and then foam molding is performed. A method for manufacturing a construction board, which comprises cutting off a part of a protrusion formed by a groove in an upper mold on the back side of a synthetic resin molded product.