EP0734360A1

EP0734360A1 - Article, particularly a covering panel for buildings, and method for making same

Info

Publication number: EP0734360A1
Application number: EP95902832A
Authority: EP
Inventors: Claude Champomier; Pascal Soukatchoff
Original assignee: Materiaux de Construction International
Current assignee: Materiaux de Construction International
Priority date: 1993-12-16
Filing date: 1994-12-05
Publication date: 1996-10-02
Also published as: YU73794A; CA2179173A1; FR2714048B1; WO1995016644A1; FR2714048A1; AU1193695A; JPH09506582A; US5779957A

Abstract

An article comprising a hydrated matrix containing 100 parts by weight of cement and around 80-120 and preferably around 100 parts by weight of sand with a grain size of less thant 1 mm, and alkali-resistant reinforcing glass fibres in a proportion of around 3-4 wt %, preferably 3.5 wt %, relative to the hydrated matrix, said article having a density no greater than 1.85. The article may be used as a covering panel for buildings, and particularly as an imitation slate covering panel.

Description

"Article, notaπroent building cladding plate, and method of manufacturing such an article".

The present invention relates to a shaped article of the type comprising a hydrated matrix containing cement and sand and reinforced with fibers. It applies in particular to building cladding elements, in particular to roofing sheets of buildings imitating slate.

It has already been proposed, for example in EP-A-165 388, to produce plates of the aforementioned type, shaped by plastic deformation. However, these known plates are heavy because they are very dense (density greater than 2), and fragile and cannot be produced at low thicknesses without risk of breaking or cracking.

The object of the invention, on the contrary, is to allow the production of thin plates which can be conveniently used for coating buildings, in particular on the roof and with the appearance of slate.

To this end, the subject of the invention is a shaped article of the aforementioned type, characterized in that the hydrated matrix contains 100 parts by weight of cement and approximately 80 to 120 parts by weight, preferably approximately 100 parts by weight, of sand with a particle size of less than 1 mm, and in that the reinforcing fibers are alkali-resistant glass fibers, present in a proportion of 3 to 4% by weight approximately, preferably approximately 3.5% by weight, relative to the hydrated matrix, the article having a density at most equal to 1.85.

The shaped article according to the invention may include one or more of the following characteristics:

- The article consists of a plate, in particular intended for the coating of buildings and, has a current thickness less than about 1 cm;

- The hydrated matrix contains a water / cement weight ratio of between 0.30 and 0.40 and preferably equal to 0.35; - the glass fibers have a length / diameter ratio of between 100 and 200 approximately;

- The hydrated matrix also contains ultra-fine particles, in particular of silica fume or meta aolin, in an amount of 8 to 12 parts by weight approximately, preferably approximately 10 parts by weight;

- The hydrated matrix also contains an extrusion agent such as carboxymethylcellulose, in an amount of about 1 part by weight; - The hydrated matrix also contains a dye, in particular an iron oxide, in an amount of approximately 4 parts by weight;

- The article has an approximately smooth bottom surface and an upper surface imitating slate;

- The plate has a thickness at most equal to 6 mm;

- The article has along an edge of the catching reliefs projecting downward and an upper surface imitating the slate, possibly provided with ribs ensuring one seal between the articles arranged overlapping;

The invention also relates to a method of manufacturing an article shaped in the form of a plate, in particular as defined above, comprising a hydrated matrix containing cement and sand and reinforced with fibers, this method comprising the steps following:

(a) the constituents are mixed until a substantially homogeneous paste is obtained; (b) the dough is extruded in the form of a strip; and, after or before cutting this strip; (c) the strip is laminated.

This process can include one or more of the following characteristics:

- The method further comprises a step (d) of compression shaping of the laminated plates, preferably simultaneously carrying out the final cutting of the plates to the desired dimensions; - The extruded strip has a width substantially equal to that of the plates to be obtained, and in that the rolling is carried out between rolling members free to rotate;

- The extruded strip has a width markedly less than the width of the plates to be obtained, and in that the rolling is carried out by braking the strip so as to increase its width.

An example of implementation of the invention will now be described with reference to the appended drawings, in which:

- Figure 1 shows in perspective a cover plate according to the invention;

- Figure 2 is a similar view of another embodiment of the cover plate according to the invention;

- Figures 3 to 5 schematically illustrate, respectively, three successive stages of transformation leading to the plate of Figure 1;

- Figures 6 to 8 are views similar to Figures 3 to 5 respectively but relating to the plate of Figure 2;

- Figures 9 to 11 illustrate, respectively, schematically, three successive stages of the manufacture of a coating plate according to the invention; - Figure 12 illustrates in top view, schematically, a first embodiment of the extrusion and rolling steps;

- Figures 13 and 14 are views taken in section along lines XIII-XIII and XIV-XIV, respectively of Figure 12;

- Figure 15 illustrates in top view, schematically, a second embodiment of the extrusion and rolling steps; and - Figure 16 is a sectional view taken along line XVI-XVI of Figure 15.

In the application example which will be described, thin plates 1 of black or anthracite color are produced intended for roofing buildings and having the appearance of slate. These plates have a common thickness of the order of 5 to 6 mm in an "flat" embodiment shown in FIG. 1.

In another embodiment, shown in Figure 2 without respecting the proportions, they have a current thickness of about 9 mm and they are provided along an edge 2, constituting in service the upper edge of the plate, of hooking reliefs 3 projecting downwards having a height of the order of 8 mm; they also have, on their upper surface, along said upper edge and of the two lateral edges, joint ribs 4. The lateral edges have a thickness reduced by approximately half, one from the top, the other from from the bottom, and their ribs 4 are directed upwards for the first and downwards for the second, so as to allow their fitting from one plate to the adjacent plates. In addition, the lower edge of the plate has a recess adapted to receive the rib 4 of the upper edge of the plates located immediately above. The plates 1 typically have dimensions ranging from 200 X 300 mm to 300 X 600 mm, and they are relatively light, with a density of the order of 1.8.

In each embodiment, the upper surface of the plate 1 has irregularities 5 imitating slate, called "slate cleavage".

The plates 1 are ductile: they have a breaking strength of the order of 14 to 18 MPa, and an elongation at break of at least 0.15%.

The manufacture of plates 1 will now be described.

Very generally, is prepared by mixing ^• a paste from a number of components, which will be described in detail later, and extruding the dough in the form of a relatively thick band, that we cut into blocks 6 (Figure 3). Then these blocks are laminated to obtain blanks 7 having approximately the desired final thickness for the current thickness of the plates 1 (FIG. 4). Then, the upper surface of the blanks 7 is conformed by means of shaping plates 8 (FIG. 5) with sharp periphery edges, which simultaneously carry out the final cutting of the plates 1 to their desired dimensions. Finally, the plates 1 are steamed.

In the case of the flat plates 1 of Figure 1, the rolling and shaping are carried out on flat supports 9 (Figures 3 to 5), while, in the case of the plates 1 with reliefs 3 of Figure 2 (Figures 6 to 8), supports 10 are used which have recesses 11 in which the dough is forced during rolling to form the reliefs 3. As for the upper reliefs 4, they are formed by recesses 12 which are provided with the plates conformation 8 (Figure 8).

The manufacture of plates 1 will now be described in more detail, with a numerical example. The starting paste is made with following constituents, which form a hydrated matrix reinforced by glass fibers:

(a) Matrix: a.l Dry materials: - high quality Portland cement, for example HPR cement: 100 parts by weight

- silica smoke: 10 parts by weight

- fine sand with a particle size less than 800 μm at 1 mm: 100 parts by weight - extruding agent (carboxymethylcellulose): approximately 1 part by weight

- black dye (iron oxide): approximately 4 parts by weight. a.2 Water: 35 parts by weight, or 16% by weight relative to dry matter.

(b) Reinforcement fibers:

These are alkali-resistan¬ glass fibers present in a proportion of 3.5 by weight relative to the hydrated matrix (dry matter + water). These fibers can in particular be fibers having a length of 6 to 12 mm, made up of 200 filaments of 14 μm in diameter, ie a length / diameter ratio of between 100 and 200 approximately. Suitable glass fibers are non-water-soluble sizing fibers commercially available under the trademark "Cemfil".

All of the constituents described above are kneaded in a relatively intense and brief manner to obtain a thick paste, having roughly the consistency of a modeling clay, in which the glass fibers have remained intact.

To describe the successive stages of the treatment of this dough, with reference to FIGS. 9 to 11, we will take the example of the flat plates 1 of FIG. 1. The dough is introduced into an extruder at screw 13 (Figure 9), which laminates it and provides a continuous strip 14 of rectangular section, which is deposited on a belt conveyor 15.

A cross-cutting device 16 forms, from the strip 14, a succession of blocks 6, which are conveyed by a second belt conveyor 17, at higher speed in order to space them apart.

A third belt conveyor 18 carrying a succession of supports 9 joins obliquely, below, the downstream end of the conveyor 17. The speeds are synchronized so that, at the end of the conveyor 15, each support 9 receives a block 6, always in the same relative position. Each assembly 6-9 then passes over a fourth belt conveyor 19, which takes it through a rolling station 20 shown diagrammatically in FIG. 10.

The station 20 comprises a train of rollers or rolling 21 to 23 arranged transversely above the conveyor 19, closer and closer to the latter. Thus, the height of each block 6 is reduced in three stages to a value which is substantially that of the final plate 1 to be obtained.

Each support 9, at the outlet of the rolling station, in this way carries a blank 7 of small thickness, which is carried by the conveyor 19 to a shaping station 24 shown schematically in Figure 11. At station 24, each support 9 is deposited on a fourth belt conveyor 25 above which is a fifth belt conveyor 26. The latter carries at regular intervals bases 27 on each of which is fixed a shaping plate 8, whose sharp peripheral edges are indicated by 28. The assemblies 27-8 have only been shown in FIG. 11 on the strand of the conveyor 26 adjacent to the conveyor 25. The conveyors 25 and 26 are driven in a synchronized manner so that each shaping plate 8 comes to cover exactly a blank 7 by cutting the periphery to the desired dimensions while conforming the upper surface with the aforementioned slate cleavage.

In this way, when the shaping plates 8 move away from the conveyor 25, the latter deposits on a discharge conveyor 29, the supports carrying plates 1 having the desired shape, which only remains to be steamed for obtaining the finished product imitating the relatively light and ductile slate, which was described above.

The production of the plates 1 of the Figure is identical in all respects to what has been described above, except that the supports 9 are replaced by the supports 10 of Figures 6 to 8 and that the shaping plates 8 include the recesses 12 mentioned above. The extrusion carried out in 13 is necessary to give the dough the plasticity required for undergoing rolling and shaping. However, this extrusion has the result of preferentially orienting the glass fibers, whereas it is generally desired to obtain isotropic mechanical properties for the plates 1. It is therefore necessary to reorient the glass fibers after extrusion, this which can be carried out during rolling, as illustrated in Figures 12 to 14 or as illustrated in Figures 15 and 16.

In the case of FIGS. 12 to 14, the extruder 13 comprises at its outlet a chamber or mouth 30 progressively variable section from a circular section (Figure 13) to a flattened section (Figure 14) having substantially the desired width for the plates 1 The passage area decreases between these two sections in a ratio of 1 to 5 to 1.

With such an extruder, the glass fibers of the strip 14, and therefore of the blocks 6 after cutting at 16, are preferably oriented in the transverse direction. To correct this, in station 20, the conveyor 19 is replaced by idle support rollers 31, some of which are arranged below the laminating rollers 21 to 23, and these and / or the rollers 31 are rotated at predetermined speeds. These speeds are chosen so as to accelerate the dough longitudinally, as a function of the reduction in thickness ensured by each rolling roll, so as to keep the width of the blocks 6 substantially constant. This acceleration, in turn, causes the longitudinal reorientation glass fibers, ultimately leading to a substantially homogeneous and isotropic distribution of these fibers.

In the case of FIGS. 15 and 16, on the contrary, the extruder does not include a mouth 30, and the extruded strip 14 has a width much less than that of the plates 1; the glass fibers are then preferably oriented in the longitudinal direction. To remedy this anisotropy, the sectioning 16 is postponed after the shaping station 24, and the strip 14 is continuously deposited on the supports 9 (or 10) at. abutted against each other. In the laminating station, the supports are carried, without possible sliding, by the conveyor 19. The latter is driven at constant speed, while the laminating rollers 21 to 23 are either driven in synchronization with this conveyor 19, or mounted crazy. In this way, no longitudinal sliding of the dough during rolling is possible, which forces this dough, at each thickness reduction at station 20, to spread transversely. lement. Again, a substantially homogeneous and isotropic distribution of the glass fibers in the finished product is obtained in this way.

With regard to the constituents of the starting paste, the following remarks can be made:

(1) Silica smoke can be present in proportions ranging from 8 to 12 parts by weight approximately. Its function is to facilitate extrusion by improving the plasticity of the dough, and it also improves the mechanical properties of the final plate. These effects are insufficient below 8 parts by weight, while the plasticity drops excessively, during extrusion, above 12 parts by weight.

As a variant, the silica smoke can be replaced, in the same proportions, by other ultrafine particles, in particular by metakaolin, which is kaolin treated at 800 ° C. so that it becomes pozzolanic. The term “ultrafine particles” is generally understood to mean particles whose BET specific surface area is between 10 and 30 m ² / g.

(2) The sand can be present in proportions of 80 to 120 parts by weight. It plays an anti-cracking role. Below 80 parts by weight, a tendency to crack the plates 1 appears. Above 120 parts by weight, a loss of the mechanical properties of the plates 1 is observed.

(3) The water can be present in a narrow fork between 0.30 and 0.40 relative to the weight of the cement. Below 0.30, it is no longer possible to use the dough, and above 0.40, free water remains in the dough, which leads to excessive porosity of the product. finished.

(4) The glass fibers must be present in a proportion of approximately 3 to 4% relative to the weight of the hydrated matrix. Below 3%, the reinforcement is insufficient, and above 4% there appear rheological difficulties, that is to say that the dough has insufficient plasticity for its treatment of rolling and conformation described above.

If the indications provided are respected, o obtains a substitute for slate which is relatively light, not very fragile and easy to use. With the flat plates of Figure 1, you can make roofs in the same way as with natural slate plates (two-thirds overlap), while, with the relief relief plates of Figure 2 , a much smaller overlap area, only up to the top ribs 4, is sufficient.

Claims

1 - Shaped article (1), of the type comprising a hydrated matrix containing cement and sand reinforced with fibers, characterized in that the hydrated matrix contains 100 parts by weight of cimen and 80 to 120 parts by weight approximately, preferably about 100 parts by weight of sand with a particle size of less than 1 mm, and in that the reinforcing fibers are alkali-resistant glass fibers, present in a proportion of 3 to 4% by weight approximately, preferably about 3.5% by weight, relative to the hydrated matrix, the article having a density at most equal to 1.85.

2 - Shaped article according to claim 1, consisting of a plate, in particular intended for the coating of buildings, having a current thickness less than 1 cm approximately.

3 - shaped article according to claim 1 or 2, characterized in that the hydrated matrix contains a water / cement weight ratio of between 0.30 and 0.40 and preferably equal to 0.35.

4 - shaped article according to any one of claims 1 to 3, characterized in that the glass fibers have a length / diameter ratio of between 100 and 200 approximately.

5 - shaped article according to any one of claims 1 to 4, characterized in that the hydrated matrix also contains ultra-fine particles, in particular of silica fume or metakaolin, in an amount of 8 to 12 parts by weight about, preferably about 10 parts by weight.

6 - shaped article according to any one of claims 1 to 5, characterized in that the hydrated matrix additionally contains an extrusion agent such as carboxymethylcellulose, in an amount about 1 part by weight.

7 - shaped article according to any one of claims 1 to 6, characterized in that the hydrated matrix additionally contains a dye, in particular an iron oxide, in an amount of approximately 4 parts by weight.

8 - Shaped article according to claims 2 and 7 taken together, characterized in that it has an approximately smooth lower surface and an upper surface imitating slate.

9 - shaped article according to claim 8, characterized in that the plate (1) has a thickness at most equal to 6 mm.

10 - shaped article according to claims 2 and 7 taken together, characterized in that it has along an edge hooking reliefs (3) projecting downward and an upper surface imitating slate, possibly provided with ribs (4) ensuring sealing between the articles arranged to overlap.

11 - Process for manufacturing a shaped article (1) in the form of a plate, in particular according to any one of Claims 1 to 10, comprising a hydrated matrix containing cement and sand and reinforced with fibers, this process comprising following steps :

(a) the constituents are mixed until a substantially homogeneous paste is obtained;

(b) the dough (at 13) is extruded in the form of a strip (14); and, after or before cutting (16) of this strip;

(c) the strip is laminated (at 20).

12 - Process according to claim 11, further comprising a step (d) of compression shaping (at 24) of the laminated plates (7), producing preferably simultaneously the final cutting of the plates (1) to the desired dimensions.

13 - Process according to claim 11 or 12, characterized in that the extruded strip (14) has a width substantially equal to that of the plates (1) obtained, and in that the rolling takes place between rolling members (21 , 31) free to rotate.

14 - Process according to claim 11 or 12, characterized in that the extruded strip (14) has a width significantly less than the width of the plates (1 to be obtained, and in that the rolling is carried out and braking the strip so to increase its width (Figures 12 to 14).