CN1665996A - Wood beam board - Google Patents

Abstract

The present invention relates to a mineral-bonded wood strand cement (magnesite, gypsum) board consisting of a mixture of wood strands or other similar fibrous material, water, a suitable binder such as cement, magnesite or gypsum, and possibly additives, which mixture is baked under pressure to form a board with a practically completely closed surface. For the board according to the invention, the wood strands used are wider but thinner than the wood strands used hitherto in (acoustical) wood wool cement (magnesite, gypsum) boards. The invention also relates to a method for manufacturing such a wood strand cement (magnesite, gypsum) board.

Description

Wood beam board

The present invention relates to a mineral bonded wood strand cement (magnesite, gypsum) board made of wood strands or other similar fibrous materials (e.g. wood wool, films, chips, flakes, etc.), such as cement, magnesite A suitable binder such as earth or gypsum, and possibly additives, is baked under pressure to form a board with virtually completely closed surfaces.

Wood wool cement boards and fiber cement boards are used worldwide in a large number of different applications. The advantage of these boards over other boards is durability and resistance to fire, moisture, rot, mold and termites.

Wood wool cement boards have been known for about a century. These boards are made of wood wool, preferably coiled fibers of limited width, and cement, magnesite or gypsum. These known plates have an open matrix and are therefore less dense. Originally, these boards were used for insulation purposes and as a base for plastering ceilings. Today, these panels are also used for decorative purposes and as sound-absorbing panels. These applications are made possible by the introduction of automatic machines for the manufacture of these plates. With the development of machines with control systems for precise dosing and mixing of raw materials, it became feasible to distribute the mixture evenly into the mould, to stack and squeeze the mold with the new mixture, and to manufacture panels of constant quality. Due to the presence of these machines it is possible to manufacture high quality boards at low cost. In particular, by using wooden molds (concrete formwork) and low-pressure presses, the cost of production line equipment for wood wool cement boards is low.

However, due to their open matrix structure, wood wool cement boards are unsuitable for constructions like exterior cladding and roofing, for which it is important that the surface is closed and waterproof. Furthermore, the strength of wood wool cement boards is insufficient for this application.

Fiber cement corrugated boards or slabs or shingles are used today, among other boards, for applications like cladding and roofing. These boards and articles have a closed matrix and are waterproof. Optionally, the surface of the slab may have reliefs, for example, slate, brick or imitation wood textures. Until recently, these fiber cement boards were mainly made of cement and asbestos fibers, which were suitable due to the durability, strength and low cost of these materials. In many countries, asbestos fibers have now been replaced by cellulose and man-made fibers, mainly due to legislation banning the use of asbestos, which is dangerous for manufacturers and processors of boards. However, a disadvantage of fiber cement boards is that these boards are not as strong and durable as asbestos boards and man-made fibers and hard cellulose are expensive.

Dutch patent 10010195 describes a wood wool cement board which has the advantages of wood and fiber cement boards in terms of durability and resistance to fire, moisture, rot, mold and termites.

However, these boards have a number of inherent disadvantages.

One of the disadvantages is the occurrence of capillary cracks on the surface in a compressed upper layer made of cement mortar or other sealing material, especially if the cement layer has not been treated with a coating such as painting. Another disadvantage is that due to the low density of these boards, the density is 800 to 900kg/m ³ , and the bending strength is still very different. In addition, the screwability, nailability and fixation of screws and nails of these boards Ability is also problematic.

Other problems arise during the manufacture of these panels, like profiling, applying the tongue and groove, and bevelling the edges of the panel. In addition, under the effect of changing moisture content, these plates will bend due to not being in balance with the same surface.

Said invention aims to provide a wood bundle cement (magnesite, gypsum) board capable of eliminating the above-mentioned disadvantages.

To this end, the present invention provides a wood-bundle cement (magnesite, gypsum) board made of a wood-bundle or similar fibrous material, water, a suitable bonding agent such as cement, magnesite or gypsum. made of a mixture of additives, and possibly additives, which is baked under pressure to form a board with a virtually completely closed surface, characterized in that the strands of wood are wider but thinner than the wood filaments still used for sound-absorbing purposes until now Wood wool used in cement (magnesite, gypsum) boards.

Surprisingly, it has been shown that with such wider and finer wood strands than have hitherto been used in sound-absorbing wood wool cement boards and by omitting a compressive upper layer consisting of cement mortar or other sealing material, comparable Effectively eliminate the above disadvantages.

For better results, it is advantageous if the wood bundles have a width of 1-12 mm or more, preferably 3-10 mm, and a thickness of 0.15-1.0 mm, preferably 0.15-0.3 mm.

Surprisingly, it has been shown that with a wooden bundle having sharp edges, the edges of the wooden bundle no longer show through. Furthermore, it shows that whenever the wood strands are distributed randomly, a smooth and almost bump-free surface can be obtained after pressing without the need for a covering of sawdust and cement as described in Dutch patent 1010195.

Since the panels according to the invention have a density between 900 and 1200 kg/m ³ , preferably between 1000-1100 kg/m ³ , compared to the known panels with a density of 800 to 900 kg/m ³ described in the aforementioned Dutch patent , the plate of the present invention has higher bending strength.

In addition, the boards according to the invention are better nailed and screwed, and the screws, staples and nails are better fixed in this new material.

Said such high density boards lead to great improvements with respect to board handling, such as profiling, applying tongue and groove, and bevelling the edges of the board.

It should be noted that although the board can be painted or painted, it does not need to be painted in order to obtain a particularly smooth surface. It has been confirmed that the panels are waterproof without the need for further surface treatment such as painting.

Surprisingly, it has been shown that the use of long strands of wood according to the invention results in more than twice the flexural strength set for cement-bonded particle boards with a density of about 20% lower, additionally increasing the board's Pretty cheap to manufacture.

Boards according to the invention may be provided on one side with eg a relief of brick, slate or wood texture, which makes them suitable for use as durable cladding or backing boards on building exteriors.

Another important advantage of the panels is that they are resistant to fire, moisture, rot, mold, and freezing and frost. In addition, they are resistant to various climatic conditions as well as the destructive action of termites.

The panels according to the invention are quite durable and can be used successfully in tropical countries such as Central America (Honduras, Guatemala, El Salvador, Nicaragua) that are afflicted by hurricanes, storms and earthquakes.

Furthermore, the invention relates to an operation for the manufacture of wood beam cement boards, characterized by the following steps:

a) dispensing a mixture of wood strands, water, and cement, magnesite or gypsum into the mold;

b) pile up molds with raw materials to the desired height;

c) pressurizing the stack of molds with raw material to obtain the desired board density; and

d) This height is maintained by connecting the so-called bottom below the stack with the top above the stack by means of connecting rods during the initial baking phase of the cement, magnesite or gypsum.

Wooden bundles are used with a width of 1-12 mm or more, preferably 3-10 mm, and a thickness of 0.15-1.0 mm, preferably 0.15-0.3 mm.

It is particularly advantageous to use wooden bundles with sharp edges, especially if an angle of less than 120° is provided on the wooden bundles.

Besides, to manufacture the panel, two plywood molds can be used as steel cover panels for pressure equalization.

To manufacture wood-bundle cement (magnesite, gypsum) boards with convex faces according to the invention, a separate board is placed on top of the mold itself and it has opposing profiles.

For a certain convexity, it is advantageous to distribute a mixture of wood bundles, water and cement on the counter convex plate which will then be pressurized to obtain the desired convexity, without the additional use of cement possibly mixed with short fibers such as sawdust, Sealing layer of magnesite or gypsum.

In a preferred embodiment of the procedure according to the invention, during the application and distribution of the wood bundles, water and cement, magnesite or gypsum, at least part of the wood bundles are oriented more towards the The length of the board is longitudinal. Due to this orientation of the wood bundles relative to the longitudinal direction of the board, the variation of the moisture content is improved, and the strength and elasticity of the board in the longitudinal direction and the linear stability in this direction will be increased.

Where the boards are manufactured with sufficient thickness, they can be sawn into planks or sheets or planks. I-beams and other profiles can be assembled from elongated sheets, battens or planks obtained according to the invention. These slender sheets, slabs and beams are very suitable for construction work due to their strength, stability and their resistance to fire and termites, especially in countries with many wooden buildings such as USA, Scandinavia, Canada wait. These planks are also advantageously used as durable exterior cladding for buildings.

It is obvious that the invention described is not limited by the claims.

Claims (14)

1. Wood bundle cement (magnesite, gypsum) boards, made from a mixture of a wood bundle or similar fibrous material, a suitable binder such as cement, magnesite or gypsum, and water with possible additives , the mixture is baked to form a board with practically completely closed surfaces, characterized in that the wood strands are wider but thinner than those hitherto used in (sound-absorbing) wood wool cement (magnesite, gypsum) boards Silk. 2. Board according to claim 1 , characterized in that the wooden bundles have a width of 1 to 12 mm or more, preferably 3 to 10 mm, and a thickness of 0.15-1.0 mm, preferably 0.15 to 0.3 mm. 3. A board as claimed in claim 1 or 2, characterized in that the edges of the bundles of wood are sharp. 4. The panel according to claims 1-3, characterized in that the edges of the wood strands are sharp and have an angle of less than 120°. 5. the manufacture method of wood beam cement (magnesite, gypsum) board as claimed in claim 1-4, is characterized in that, described operation process comprises the following steps at least: a) dispensing a mixture of wood strands, water, and cement, magnesite or gypsum into the mold; b) stacking the molds with the raw materials to a desired height; c) pressurizing the stack of said molds with said raw material so that said boards acquire a desired density; and d) During the initial baking phase of the cement, magnesite or gypsum, the required height is maintained by utilizing the bottom below the stack and the top above the stack connected by connecting rods. 6. A method according to claim 5, characterized in that the wood bundles employed have a width of 1-12 mm or more, preferably 3-10 mm. 7. A method according to claim 6, characterized in that the wood bundles used have a thickness of 0.15-1.0 mm, preferably 0.15-0.3 mm. 8. A method as claimed in claim 5, 6 or 7, characterized in that the bundles of wood employed have sharp edges. 9. The method according to claims 5-8, characterized in that the edges of the bundles of wood are sharp and have an angle of less than 120°. 10. A method according to claims 5-9, characterized in that a pair of opposing profiles is located at the bottom of a ledge, each top of the mold having opposing profiles. 11. A method according to claims 5-10, characterized in that a mixture of wood strands, water and cement is dispensed on the raised plate, which will then be pressurized to obtain the desired profile, without additional Use cement, magnesite or gypsum. 12. The method according to claims 5-11, characterized in that, during the application of the mixture consisting essentially of wood bundles, water and cement, magnesite or gypsum, a transverse direction relative to the length of the board is applied. than, at least some of the wood bundles are positioned more longitudinally of the board length. 13. Beams, slivers, planks or planks sawn from thicker plates as claimed in claims 1-12. 14. I-beams or other profiles assembled from elongated sheets, battens or slabs obtained according to claim 13.