FR3074713A1 - METHOD FOR PREPARING A WOODEN POST FOR PARTIALLY VERTICALLY RECOVERED INTO THE FLOOR, AND WOODEN POSTS PREPARED, IN PARTICULAR FOR MAINTAINING A TELEPHONE OR ELECTRIC LINE - Google Patents

Abstract

The invention relates to a method for preparing a wooden post (1) intended to be partially embedded vertically in the ground, which is remarkable that it consists in covering at least partially the embedding zone (2) of the post (1) of a polyurethane resin (3) having a shore hardness D of between 50 and 70 to form a shell (4) for rigid protection, waterproof and barrier effect against moisture and molds or substances contained in the soil.

Description

PROCESS FOR THE PREPARATION OF A WOOD POST INTENDED TO BE PARTIALLY

VERTICALLY RECESSED INTO THE GROUND, AND PREPARED WOOD POSTS, PARTICULARLY FOR MAINTAINING A TELEPHONE OR ELECTRIC LINE

Technical area

The present invention relates to the technical sector of the preparation of wooden poles intended to be used for the maintenance of telephone or electric lines, and relates more particularly to a process for the preparation of such a wooden pole.

Prior art

It is known in the state of the art to use wooden poles partially embedded vertically in the ground, in order to maintain, for example, electrical or telephone lines. Depending on the length of the pole, the latter is embedded in the ground at a depth varying for example from 1.40 m for a 9 m pole to 2.50 m for a 20 m pole.

One of the disadvantages that results from embedding the pole in the ground is its exposure to moisture or mold, which shortens its lifespan.

To solve this technical problem, it is known to prepare the post, at its embedding zone, so that it has sealing means and means for combating and preventing mold. For example, it is known to carry out an antifungal chemical treatment of the embedding zone, and to coat the latter with a heat-shrinkable plastic film, or else for example with tar.

However, these protections have some drawbacks, in particular in terms of life, or reliability of the protection. Indeed, the heat-shrinkable film which provides a seal and a barrier against mold has a certain fragility and tears easily when it is embedded in the ground. Regarding the application of a tar, it provides a seal, but does not provide a barrier against mold. In addition, the tightness is limited in time since the tar tends to crack and crack when the wood expands or contracts depending on the temperature and humidity.

Expose the invention

One of the aims of the invention is therefore to propose a method for preparing a wooden post intended to be partially embedded vertically in the ground, making it possible to increase the mechanical resistance of its embedding zone, as well as of it impart sealing properties and resistance to mold, or any substances present in the soil.

To this end, a process has been developed for the preparation of such a remarkable wooden post in that it consists in covering at least partially the recessing area of the post with a polyurethane resin having a shore hardness D included. between 50 and 70 to form a rigid, waterproof protective shell with a barrier effect against moisture and mold or substances contained in the soil.

In this way, the prepared post has an embedding area coated at least in part with a rigid shell making it possible to increase the mechanical resistance of the post, and to increase its service life.

According to a particular embodiment for forming the resin, two components are sprayed together, the mixture of which polymerizes.

Preferably, the two components are sprayed together at a temperature between 55 and 66 degrees.

Preferably, before spraying the two components, they are stored separately and heated to a temperature between 60 and 71 degrees.

Advantageously, the two components are sprayed together at a pressure greater than 130 bars.

According to a particular embodiment, the first component is an isocyanate and the second component is a polyol or an amine, preferably present in the same amounts

The invention also relates to a wooden post of the aforementioned type, remarkable in that it comprises a rigid shell covering at least in part the recessing area of the post in the ground, the shell being formed by a polyurethane resin having a shore hardness. D between 50 and 70.

According to a particular embodiment, the polyurethane resin consists of a mixture of isocyanate and polyol or of a mixture of isocyanate and amine.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will emerge clearly from the description which is produced below, by way of indication and in no way limiting, with reference to the appended schematic figures in which:

Figure 1 is a schematic representation of a wooden post before placing the resin;

Figure 2 is a schematic representation similar to that of Figure 1, after placement of a thermoplastic stretch film, and foam protection;

Figure 3 is a schematic representation of the wooden post after preparation and installation of the resin.

Detailed description of the invention

The invention relates to a wooden post (1) intended to be partially and vertically embedded in the ground in order to maintain, for example, a telephone or electric line.

In general, this type of post (1) has a length of between 9 and 20 meters with a slightly conical conformation narrowing from the base to the top.

Depending on the length of the post (1), the latter can be embedded in the ground at a depth of 1.40 m for a post (1) of 9 m to a depth of 2.50 m for a post (1) 20 m.

According to the invention, the post (1) is coated and coated, at a part of its embedding zone (2) in the ground, with a polyurethane resin (3) having a Shore D hardness of between 50 and 70, preferably 60, in order to form a rigid shell (4) around said post (1).

This rigid shell (4) makes it possible to mechanically protect the embedding area (2) of the post (1), but also makes it possible to ensure sealing properties, and acts as a barrier to substances present in the soil or to mold. The shell (4) is rigid, but has a certain flexibility and elasticity allowing it to adapt to variations over time in the dimensions of the wooden post (1), without losing efficiency in terms of sealing, barrier and protection. mechanical.

To reduce costs, the polyurethane resin (3) extends over the recess area (2) of the post (1) over a length of about 90 cm, and is positioned so that when the post (1) is embedded in the ground, 40 cm of resin protrude from the surface, materialized in the figures by the line (S), and 50 cm are below the surface. Below 50 cm below the surface, the risk of mold of the post (1) is low because the area is not conducive to the development of fungus. Of course, it is possible to completely cover the embedding zone (2) of the post (1) without departing from the scope of the invention.

The polyurethane resin (3) can be of any suitable composition, the main thing is that it has sufficient rigidity to resist tears and possible impacts, as well as sufficient elasticity to adapt to variations in the dimensions of the wood during the life of the post (1).

For example, the resin is a polyurethane resin (3) consisting of a mixture of isocyanate and polyol, or a mixture of isocyanate and amine. Preferably, the mixture contains 50% isocyanate and 50% polyol or amine.

In practice, and with reference to FIG. 1, before proceeding with the installation of the polyurethane resin (3), the surface of the embedding zone (2) of the post (1) is ginned to remove splinters and fibers found. Preferably, and with reference to FIG. 2, protective masks (5), for example made of foam, are then positioned on each side of the area to be treated. It is possibly possible to position around the post (1), at the level of the embedding zone (2), a stretch film (6) around the circumference of the post (1) taking care to leave a free strip of approximately 10 cm on either side of the film (6) for hanging the polyurethane resin (3) on the post (1). The stretch film (6) is, for example, used when the wooden post is too wet.

Finally, with reference to FIG. 3, the polyurethane resin (3) is applied with a heated high-pressure gun, protected from the weather. For this purpose, the post (1) is for example placed on a drive roller allowing the rotation of said post (1) for the application of a uniform resin layer (3). The resin (3) is sprayed over the entire area to be treated, for example in several passes, to obtain a thickness of 1.5 to 3 mm. The temperature of the wood should not be lower than 15 °. Preferably, the resin (3) is left dried between the different passes. The drying time of the resin (3) is between 6 and 9 s. After application and drying of the resin (3), any protective masks (5) are removed.

To form the resin, the isocyanate and the polyol or amine are sprayed together, the mixture of which polymerizes in seconds. In practice, before mixing, the two components are stored separately and heated to a temperature between 60 and 71 degrees. Then, to form the resin (3), the two components are sprayed together at a temperature between 55 and 66 degrees and at a pressure greater than 130 bars.

From the above, the invention provides a method for preparing a post (1), as well as a prepared post (1) whose embedding zone (2) has increased resistance, is waterproof, and is protected against molds or other substances present in the soil. In this way, the life of the post (1) is increased.

Claims (9)

claims 1. Method for preparing a wooden post (1) intended to be partially embedded vertically in the ground, characterized in that it consists in covering at least partially the embedding zone (2) of the post (1) of a polyurethane resin (3) having a shore D hardness of between 50 and 70 to form a rigid protective shell (4), waterproof and with a barrier effect against humidity and molds or substances contained in the soil. 2. Method according to claim 1, characterized in that to form the resin, two components are sprayed together, the mixture of which polymerizes. 3. Method according to claim 2, characterized in that the two components are sprayed together at a temperature between 55 and 66 degrees. 4. Method according to claim 2, characterized in that before mixing, the two components are heated to a temperature between 60 and 71 degrees. 5. Method according to claim 2, characterized in that the two components are sprayed together at a pressure greater than 130 bars. 6. Method according to claim 2, characterized in that the two components are an isocyanate, and a polyol or an amine. 7. Method according to claim 6, characterized in that the mixture comprises 50% of isocyanate, and 50% of polyol or amine. 8. Wooden post (1) intended to be partially embedded in the ground to make a post (1) for maintaining a telephone or electric line, characterized in that it comprises a rigid shell (4) covering at least in part the embedding zone (2) of the post (1) in the ground, the shell (4) being formed by a polyurethane resin (3) having a shore hardness D between 50 and 70. 9. Post (1) according to claim 8, characterized in that the polyurethane resin (3) consists of a mixture of isocyanate and polyol, or of a mixture of isocyanate and amine.