JPS591570B2 - Waterproofing method for plate-shaped objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for waterproofing fiberboard used as a base for external walls.

Sheathing insulation fiberboard, which has traditionally been used as a waterproof plate, has asphalt added internally compared to insulation fiberboard, so its water absorption performance is significantly greater. Although it has been improved, it cannot be said to be perfect as an exterior wall base material.
Expansion and contraction may be observed due to water absorption, and after installation, there is a risk that waving may occur due to the expansion and contraction of the board, or that moisture contained in the mortar may be absorbed into the board, causing poor hardening of the mortar.

Methods to improve this water absorption include increasing the amount of asphalt added to the board, or applying asphalt to the board surface. However, in the latter case, where asphalt is applied to the surface, blocking (adhesion of polymerized boards) is particularly likely to occur. It is necessary to infiltrate the asphalt into the board, and therefore high-temperature treatment or filter treatment with a solvent is required, resulting in poor workability and labor safety problems.

In order to eliminate such drawbacks, the present invention has been developed by adding a softening point of 100 to 100 on the surface of wet fiberboard before drying.
Waterproofing treatment for fiberboard, characterized by providing a wet resin layer made of synthetic resin fibers or synthetic resin powder at a temperature of ℃ or higher, then drying the fiberboard and melting the resin layer to form a waterproof coating on the surface of the fiberboard. The present invention provides a method.

To explain the method of the present invention in detail, first, a wet resin layer with a softening point of J100°C or higher is provided on the surface of a wet fiberboard that has been subjected to wet papermaking before drying. It can be provided by combining wet sheets made of synthetic resin fibers or by applying a suspension of synthetic resin fibers or synthetic resin powder.

In this case, a thin and uniform resin layer can be provided very easily when wet sheets of synthetic fibers are combined, but the disadvantage is that the equipment is generally larger than the latter method.

On the other hand, when applying a suspension, unlike a dry fiberboard, the fiberboard is in a wet state, so the resin does not permeate into the porous fiberboard and stays on the surface, forming a resin layer. is formed. Furthermore, even if an organic substance other than resin such as pulp is mixed as an extender to the synthetic resin fibers or synthetic resin powder forming this wet resin layer at a ratio of 20% or less, the waterproof and moisture-proof coating obtained on the fiberboard surface can be improved. There is no significant loss in sex.

After the resin layer is thus provided on the wet fiberboard, the fiberboard is then dried at a temperature higher than the softening point of the wet resin layer and the resin layer is melted. The softening point of the synthetic resin fiber or synthetic resin powder is 1
The reason why the temperature was set at 00°C or higher is as follows.

That is, if the resin layer softens at a temperature of 100°C or lower, the resin layer will have a temperature of 100°C before drying due to the presence of water.
Although the temperature never exceeds ℃, it softens and forms a film on the mat surface, preventing the moisture in the wet fiberboard from passing through the resin layer in the form of vapor and evaporating, thereby inhibiting the drying of the wet fiberboard. It is from.

Therefore, the resin layer needs to be melted at the stage when the drying of the fiberboard is completed and the temperature of the mat rises. On the other hand, regarding the drying temperature, the combustion temperature of the Z organic matter mixed in the resin layer is about 180°C, and the heat resistance temperature of the plate-like material obtained by drying the fiberboard is 150 to 160°C. It is necessary to melt within this temperature range, and examples of synthetic resin fibers or synthetic resin powders that melt within this temperature range include nylon, divinylon, polyester, and polypropylene. In addition, the amount of resin solids forming the wet resin layer is, for example, 30 t/d or more in order for the waterproof resin coating formed on the surface of the plate to exhibit sufficient performance, but 5 to 100t/d because it is a plate-like material such as
It is necessary to limit the application amount to the following so that the inherent moisture permeability is not impaired. Furthermore, when using synthetic resin powder to form the wet resin layer,
Since it is difficult to obtain a film with a uniform thickness with powder larger than 100 mesh, powder smaller than this, preferably 200 mesh, is used.
Powder with a mesh size or smaller is used, and for the same reason in the case of synthetic resins and resin fibers, the fiber length is 1 to 2w1 and the diameter is 10 to
It is preferable to use one with a diameter of 50μ.

In addition, in the present invention, a wet resin layer is provided on the surface of the fiberboard in a wet state, but since the resin layer is very thin compared to the fiberboard, the moisture supplied to the fiberboard is absorbed by the fiberboard. This only increases the moisture content of the fiberboard by a few percent, and does not have a large effect on the drying of the fiberboard.

The fiberboard with the wet resin layer on its surface is dried at a predetermined temperature and then cooled to prevent the molten resin from being absorbed into the porous fiberboard and form a waterproof coating on the surface. It is something that

In Cx, the waterproof coating formed by the resin layer is formed by cooling the fiberboard while most of the resin layer is on the surface layer of the fiberboard, and a portion of the resin may permeate into the base material. Next, examples of the present invention will be shown.

Example 1 807/ made of polyethylene fiber with a softening point of 130°C
A wet sheet of Rrl2 (solid content equivalent) with a thickness of 12
After the soft fiberboard was made, it was combined with the surface of the wet mat, dried for 3 hours at 190°C using a hot air circulation dryer, and then cooled to obtain a soft fiberboard with a resin coating on the surface. .

Example 2 A suspension of nylon 66 powder of 200 mesh or less was dispersed in water at a rate of 100 f/d (solid content) to form a soft fiberboard wet mat with a thickness of 12 wm as in the previous example. After coating, it was dried and cooled under the same conditions to obtain a soft fiberboard having a resin coating on the surface.

A comparison table of the water absorption and moisture permeability of the soft fiberboards obtained in Examples 1 and 2 above and the untreated soft fiberboards is shown below.

In the table, the water absorption amount is the value obtained when water was absorbed from the surface of a 300 m square specimen for 24 hours, and the moisture permeation amount is the value obtained by testing a 200 wmL square specimen at 30°C and 90 (f:) RHl4O hours.
The results are shown below.

As is clear from the table, the fiberboard obtained by the method of the present invention is water resistant and has appropriate moisture permeability.

As described above, the present invention covers the surface of a wet-formed fiberboard in a wet state before drying with a wet sheet of synthetic resin fibers having a softening point of 100°C or higher, or with synthetic resin fibers or synthetic resin powder. After providing a wet resin layer by applying a suspension, the fiberboard is dried at a temperature higher than the softening point of the wet resin layer, the wet resin layer is melted, and then cooled to form a fiberboard. Since this relates to a waterproofing method for a plate-like object characterized by forming a waterproof coating with a resin layer on the surface, a wet resin layer is provided on the surface of the fiberboard, and the resin layer is melted to form a coating. Therefore, the resin does not penetrate into the inside of the fiberboard, making it possible to apply waterproofing without changing the original properties of the fiberboard.In addition, it can be applied to wet-sheeted fiberboard in a wet state before drying, so it can be applied to fiberboard in a wet state before drying. In comparison, it can be manufactured through a series of steps of papermaking, wet resin layer formation, and drying, and the process can be simplified.

Claims (1)

[Scope of Claims] 1. The surface of a wet-formed fiberboard in a wet state before drying is coated with a wet sheet of synthetic resin fibers with a softening point of 100°C or higher, or a suspension of synthetic fibers or synthetic resin powder is applied. After providing a wet resin layer by coating, the fiberboard is dried at a temperature higher than the softening point of the wet resin layer, the wet resin layer is melted, and then cooled to form a resin layer on the fiberboard surface. A method for waterproofing fiberboard, the method comprising forming a waterproof film. 2. The method for waterproofing a fiberboard according to claim 1, wherein the wet resin layer is made by mixing an appropriate amount of natural organic material such as pulp with synthetic resin fibers or synthetic resin powder.