JPS6223840Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a press mold for forming a fibrous diaphragm.

The fibrous diaphragm is produced by a beating process to cut, swell, and fibrillate raw material pulp, a papermaking process to deposit the fibers produced through the beating process on a diaphragm-shaped paper mesh, and a papermaking process. It consists of a pressing process in which the fiber layer is press-molded in a heated mold.

Here, to explain the pressing process in more detail, in the press forming, the moisture contained in the paper-formed fiber layer is evaporated by heating, the fiber layer is compressed by pressure, and the entanglement of the fibers increases. The overlapping fiber portions are bonded together, thereby providing the strength necessary for the diaphragm.

In the pressing step, sufficient intertwining and adhesion of the fibers cannot be obtained unless the fibers are pressed in a swollen state, that is, a state in which the fiber layer contains a certain amount of moisture, as described above.

However, when a fiber layer containing moisture is brought into direct contact with a press mold heated to 150℃ to 200℃ and heated and pressurized, the moisture evaporates instantly due to rapid heating, and Since there is no place for the generated steam to escape, the steam pressure will destroy the bonding state of the fibers.

Therefore, conventionally, a breathable cushioning material such as a flannel or a blanket is placed on at least one surface of the mold in order to cause such rapid heating and to release steam to the outside of the mold.

This cushioning material prevents rapid heating of the fiber layer and releases steam outside the mold through the cushioning material, solving the above-mentioned drawbacks. However, during the compression operation of the press, the fiber layer Some of the moisture contained in the cushioning material penetrates into the cushioning material, but during the next pressing operation, the moisture contained in the cushioning material evaporates, resulting in burnout of the surface of the cushioning material that contacts the mold surface.

Therefore, it was necessary to replace the cushioning material every certain number of presses.

Also, because the physical properties of the cushioning material change due to burnout, the temperature, pressure, and degree of steam release applied to the fiber layer vary significantly, especially immediately before and after replacing the cushioning material, making it difficult to obtain a uniform product. It had drawbacks.

Therefore, in this invention, a breathable and hygroscopic member such as foam rubber or cloth is bonded to at least one surface of the press mold, and a certain amount of moisture is further supplied to the member from inside the mold. This press die will be described in detail with reference to the drawings below.

1 is a convex mold having a truncated conical convex surface;
The convex surface is provided with a large number of through holes 1a, and the entire surface of the convex surface is covered with a material 2 having air permeability and moisture absorption properties, such as foamed rubber.

3 is a fiber layer formed in the papermaking process and contains a certain amount of water.

4 is a concave mold having a truncated conical concave surface that matches the convex surface.

Further, 6 is a steam passage for supplying water vapor to the member 2 through the small through hole 1a, and 5 is a steam opening/closing valve.

Furthermore, 1b and 4b are electric heaters for heating both molds 1 and 4, respectively.

According to the mold having the configuration of this invention, when press-molding the fiber layer 3, the valve 5 is opened to supply a certain amount of water vapor into the convex mold 1,
Add a certain amount of moisture to the member 2.

Next, the fiber layer 3 is placed in the concave mold 4 and pressed.

After pressing for a certain period of time, the fiber layer 3 is taken out and the valve 5 is further opened to supply a certain amount of moisture to the member 2 in preparation for the next pressing step.

By doing this, the member 2 can be
Since the structure is such that a constant amount of moisture can be supplied to the material, the physical properties of the member 3 can be kept constant during each pressing process, and as a result, variations in the product can be reduced even when pressed in large quantities. becomes possible.

As explained above, this invention covers at least one of the concave mold 4 or the convex mold 2 of a press mold for molding with a moisture-absorbing and breathable member 2 such as foamed rubber, and Due to the structure in which a large number of small through holes 1a are bored in the surface and the small through holes 1a are connected to the valve 5 for opening and closing steam, the physical characteristics (temperature, humidity, air permeability, etc.) of the member are controlled in each pressing process. can be kept constant, and as a result, products of constant quality can be provided.

In the above embodiment, the member 2 and the steam supply structure are applied to the convex mold 1, but the concave mold 4 or both the concave and convex molds 2 and 4 may be applied.

Further, the valve 5 can be opened and closed automatically in conjunction with the vertical movement of the mold.

[Brief explanation of the drawing]

The figure is a sectional view of the press mold for molding of this invention. 4 is a concave mold, 2 is a convex mold, 1a is a through hole, 5
12 is a steam opening/closing valve, and 12 is a member having breathable and hygroscopic properties.

Claims (1)

[Scope of utility model registration request] In at least one of the pair of concave molds 4 and convex molds 2, a large number of through holes 1a are bored on the mold surface, and the through holes 1a are connected to the water vapor opening/closing valve 5. A press mold for forming a fibrous diaphragm, characterized in that the surface of the mold is covered with a member 2 having air permeability and hygroscopicity such as foamed rubber.