WO2007042626A1

WO2007042626A1 - Wall coating polishing roller and method for making same

Info

Publication number: WO2007042626A1
Application number: PCT/FR2005/002520
Authority: WO
Inventors: Dominique Secret
Original assignee: Rm Distribution
Priority date: 2005-10-11
Filing date: 2005-10-11
Publication date: 2007-04-19
Also published as: EP1943056A1

Abstract

The invention concerns a wall finish polishing roller for eliminating the step of selection and reducing costs of raw materials, while ensuring the same or even better efficiency compared to that of natural rollers, optionally more abrasion-resistant by its coating, economical and easy to produce industrially. More precisely, the invention concerns a wall coating polishing tool produced by an industrial process comprising a grip and a planar active surface. The latter has a mean Rk parameter, corresponding to the average of five Rk parameter measurements performed in accordance with the ISO 13565-1 and 2 standards, ranging between 0.35 νm and 2 νm, preferably between 0.4 νm and 1.8 νm, more preferably between 0.45 νm and 1.7 νm, more preferably between 0.5 νm and 1.65 νm, more preferably between 0.55 and 1.4, more preferably between 0.6 νm and 1.3 νm, more preferably between 0.6 and 1.2, typically between 0.7 νm and 1 νm.

Description

WALL COATING POLISHING ROD AND METHOD OF

MANUFACTURING

The invention relates to a wall coating polishing roller and a method of manufacturing the roller. The application of some wall coverings requires a finishing step to give the desired appearance. For example, Tadelakt is known, which after having been spread on a surface must be polished by a natural pebble in order to give it the desired moire and irregular appearance.

The coating which is the subject of the patent application EP 1 099 675 is a coating making it possible to imitate the tadelakt-ci after coating "tadelakt way" - also requires such a finishing step with the aid of a polishing roller .

Traditionally, the pebble used is a natural pebble of Carrara marble type, this pebble being cut to present a flat face. It can be used with black soap.

The manufacture of such rollers is expensive and tedious since it is necessary to collect rollers, select them for their relatively ergonomic shape, then cut and sand them so that they have a flat face. This last step causing up to 50% loss of selected pebbles, it is necessary to select 2000 pebbles to hope to produce 1000 in working order, which takes at best about forty hours. In addition, the raw material is expensive.

In addition, a coating according to the EP patent application

No. 1,099,675 discloses abrasive components-calcium carbonate particles-which rapidly alter the natural rollers during the polishing step of the coating. It is therefore necessary to replace the altered pebble to maintain the same polishing quality of the coating.

The object of the present invention is to provide an industrial roller to eliminate the selection step and reduce raw material costs, the industrial roller to be suitable for finishing wall covering, have an identical or even greater efficiency compared to that of natural pebbles, possibly better resist abrasion by the coating, be economical and easy to manufacture industrially.

In order to fulfill the objectives mentioned above, the idea of the invention proposes to optimize the work of the state of the flat surface of the rollers.

More specifically, the invention relates to a wall coating polishing instrument produced by an industrial process having a gripping portion and a planar active surface, wherein the planar active surface is made by a surface treatment to present a roughness measured by an average Rk parameter, corresponding to the average of five Rk parameter measurements made according to ISO 13565-1 and

-2, between 0.35 microns and 2 microns, preferably between 0.4 microns and 1.6 microns, more preferably between 0.6 microns and 1, 2 microns, typically between 0.7 microns and 1 micron. According to particular embodiments:

the plane active surface furthermore has a surface state measured by a mean Rvk parameter, corresponding to the average of five Rvk parameter measurements made according to the standards ISO 13565-1 and -2, less than 1, 4 μm, preferably less than 1.1 μm, typically less than 0.3 μm;

The plane active surface furthermore has a surface state measured by an average Rt parameter, corresponding to the average of the five Rt parameter measurements made according to the ISO 4287 and 12085 standards, between 1 μm and 10 μm, preferably between 1 μm and 10 μm, preferably between 1 μm and 10 μm. , 5 μm and 5 μm, typically between 2 μm and 3 μm;

^"The edges of the planar surface are beveled to form a chamfer;

• the gripping portion and the planar active surface are releasably secured to each other by a fastening means; • The gripping part is taken in the group of handles made of polymer, wood, metal and ceramic;

The material of at least the planar active surface is taken from the group consisting of metals, metal alloys, ceramics, glass, and thermoplastic materials;

the material of at least the plane active surface has undergone surface hardening treatment;

the material of at least the plane active surface is taken from the group constituted by the aluminum alloy treated by anodic oxidation for a time sufficient to deposit an aluminum oxide layer greater than 10 μm, ceramics, glass, titanium alloys and steel;

• the plane active surface is composed of AS13Y30 aluminum alloy; the material of at least the planar active surface exhibits an abrasion resistance, expressed as the volume of material removed measured according to ISO standard 546-6, of less than 500 cubic millimeters.

The invention also relates to a building surface coating kit comprising: an internal coating tank which is intended to be applied to said surface and which consists of a first water paste comprising absorbent elements capable of absorbing water, - an external coating tank which is intended to be applied to said inner coating layer after drying of the latter and which consists of a second water paste, said absorbent elements comprise in combination particles of cellulose and vermiculite, and - a polishing instrument as defined above. According to particular embodiments of the kit: the first pulp comprises the cellulose particles in a dry fraction of 5%, and the vermiculite particles in a dry fraction of 1%; the first dough and said second dough each comprise calcium carbonate; the first dough comprises said calcium carbonate in a dry fraction of 50%;

The first paste further comprises glass fibers, such as fibers having a nominal diameter of less than 1 mm and a length greater than 2 mm; ^"The second paste comprises a coalescent agent suitable for promoting the particle meeting of water; ^"The second paste comprises micronized silica. The invention also relates to a method for obtaining a building surface coating from the previous kit, comprising the steps of:

(i) applying, on a building surface, an inner coating layer consisting of a first water-based paste comprising absorbent elements which are capable of absorbing water and which comprise in combination cellulose particles and vermiculite,

(ii) allowing said inner layer to dry by evaporation of the water contained therein,

(iii) applying to said inner layer an outer coating layer based on a second water paste, for obtaining said coating in which the water of said outer layer is absorbed in a reduced time by said absorbent elements ,

(iv) allowing said outer layer to partially dry by evaporation of the water it contains, then (v) polish the outer layer with the polishing instrument by making a circular motion of amplitude about 20 cm ² until you get to the touch a hard and smooth surface, similar to marble.

According to particular embodiments of the method for obtaining a coating for a building surface:

The first paste is prepared by mixing the cellulose particles in water with a dry fraction of 5%, and the vermiculite particles with a dry fraction of 1%;

The first paste is prepared by additionally diluting calcium carbonate and glass fibers in water, such as fibers having a nominal diameter of less than 1 mm and a length greater than 2 mm;

The method further comprises the steps, prior to step (i), of creating irregularities on said surface to be coated by applying removable elements, such as adhesive tapes, and between steps (ii) and iii), removal of said removable elements, to obtain following step (iii) of reliefs and recesses;

^"After having applied said internal layer in step (i) and before the latter is dry, fractions are previously removed in step (iii) where the said outer layer is applied;

The inner layer and / or said outer layer are applied "by trowel". Other characteristics of the invention will be set forth in the following detailed description with reference to the appended figures which represent, respectively:

- Figure 1: a perspective view of a one-piece roller according to the invention. - Fig 2, a bottom plan view of the roller of the figure

1, and - Figure 3, a perspective view of a roller in two separate parts detachably removable.

In the following description, a "wall coating polishing instrument produced by an industrial process" means a polishing instrument or, at the very least, a planar active surface, which has been entirely realized industrially, both the manufacture itself that the treatment of the actual surface - cutting, sanding and possibly curing - which excludes natural pebbles obtained for example from the Carrara marble. On the other hand it is necessary to distinguish the sanding step of the roller as action on the roller to obtain a surface condition of the roller itself, and the finishing step by polishing the wall covering with the aid of the roller.

In addition, the general term roller will be used to designate a polishing finishing instrument comprising a gripping portion and an active polishing portion, these two elements may be separate or in one piece. When it comes to sanding the roller, it must be understood that it is the sanding of the active part of polishing, whether it is separate or constituent of the roller. Different materials were used to make rollers, but the polishing results of the coating were qualitatively very heterogeneous, even between rolls of the same material having undergone almost identical surface treatments such as cutting of the flat face, sanding, hardening. surface by heat or chemical treatment.

The Applicant has found that the operation of sanding the roller, and more particularly the degree of sanding characterized in particular by certain parameters of surface condition Rk, Rvk and Rt (their meaning will be explained later), has a determining influence. the result of the finishing of certain wall coverings, and especially that of a building surface covering, comprising an inner coating layer which is intended to be applied on said surface and which consists of a first water paste comprising absorbent elements capable of absorbing water, and

an outer coating layer which is applied to said inner coating layer after drying thereof and which consists of a second water-based paste,

coating in which said absorbent elements comprise in combination particles of cellulose and vermiculite.

The method of obtaining such a coating comprises (i) applying to a building surface an inner coating layer of a first water-based paste comprising absorbent elements which are capable of absorbing water and which comprise in combination particles of cellulose and vermiculite, then step (ii) of allowing said inner layer to dry by evaporation of the water it contains, and then to apply (iii) on said inner layer an outer coating layer based on a second water paste, for obtaining said coating in which the water of said outer layer is absorbed in a reduced time by said absorbent elements.

The first paste is prepared by mixing the cellulose particles in water with a dry fraction of 5%, and the vermiculite particles with a dry fraction of 1%. Calcium carbonate and glass fibers are furthermore diluted so that the fibers have a nominal diameter of less than 1 mm and a length of greater than 2 mm.

Thus, the first paste of the coating comprises a dry fraction of 5% of cellulose particles and a dry fraction of 1% of vermiculite particles.

The first dough and the second dough each comprise calcium carbonate, and preferably the first dough comprises said calcium carbonate in a dry fraction of 50%. In addition, the second paste comprises a coalescing agent capable of promoting the joining of water particles, and / or micronized silica. More specifically, the coating is in the form of two distinct products which can be placed in two different packages, or can be packaged separately and grouped in a common container to form an assembly which constitutes a sales unit and which can, in addition , be associated with one or more complementary products: wax, varnish, dye, application accessories such as trowel, brushes and smoothing rollers for finishing.

The first product may be in the form of a powder which is formed of elements of different grain sizes, yarns, fibers and other solid constituents, and which must be diluted in a sufficient amount of water to obtain a paste of viscosity. desired.

The first product may also have been prepared in the factory, in which case it is presented to customers already in the form of a paste, preferably white to be used anywhere. Whether in powder form or in paste form, the first product comprises soluble elements and insoluble, mineral and / or synthetic elements, so that after it has been applied, the first product has a non-soluble surface. smooth.

But the presence of these insoluble elements also aims to allow the dough to be a kind of frame capable of plugging holes, cracks and small inequalities and can later follow the cracks that can occur to hide them completely.

Among the insoluble elements, are particles whose species and number are specially designed so that they together form, dry, an absorbent mass.

Example of a composition of such a product

• calcium carbonate: 50%

• fine vermiculite: 1% • synthetic resin powder: 1, 5%

• biocide: 0.5% • fibrous elements such as yarns: 1%

• fine particles of cellulose: 5%

• other mineral charges: 41%

Total: 100% Synthetic resin is a dispersible powder.

The fibrous elements are advantageously glass fibers with a nominal diameter of less than 1 millimeter and a length greater than 2 mm.

The biocide is a compound with a broad spectrum of killing efficiency for bacteria, mosses, molds, algae and various undesirable microorganisms.

The above composition is carried out by mixing its powdery components. Then, depending on whether the dough is prepared in the factory or when bags of powder for dilution are sold, the producer or the consumer dissolves this composition in water and carefully mixes everything to obtain a homogeneous dough.

For example, 10 kilograms of the powdery composition are prepared and then diluted in 7 liters of water with careful mixing until a paste having a viscosity of about 70,000 centipoise is obtained.

After allowing the dough to rest for a few minutes, 17 kilograms of ready-to-packaged dough are available, for example in 5 or 10 kg metal cans. To coat a square meter of surface, it takes about 1.7 kilo of the first product's dough. The use, as absorbent elements in said inner layer, of cellulose powder (not to be confused with a cellulose derivative) combined with vermiculite particles makes it possible to significantly accelerate, by capillarity, the absorption of the water contained in said outer layer, which provides an extremely reduced drying time for the coating obtained. Indeed, it appears that the use of this combination of cellulose particles and vermiculite implies a particularly advantageous synergistic effect compared to a separate use of cellulose or vermiculite as an absorbent element, the drying time obtained for the coating being at least halved in the case of a single use of vermiculite, or even three in the case of a single use of cellulose.

In addition, this combination of cellulose particles and vermiculite gives the inner layer of the first product both significantly increased coverage and ease of application, compared to inner layers incorporating only cellulose or only vermiculite.

In addition, this combination of cellulose and vermiculite makes it possible to obtain a substantially smooth internal surface layer, unlike internal layers incorporating only cellulose or vermiculite which have undesirable irregularities or reliefs.

The second product must be applied to the first and form a finishing layer, knowing that this word should be understood as meaning that the coating is self-sufficient with both products, but this topcoat can itself receive the varnish, or wax.

The second product may be in the form of a dough prepared in the factory, possibly colored, to be packaged or already packaged in containers such as bins, for example 5 or 10 kilos of capacity, and containing the quantity of dough ready for use. use of the second product which may cover the same number of square meters as the quantity of the first product sold in powder or paste form. The paste of the second product may be white, in which case the consumer who wishes to have a colored topcoat, must obtain, possibly by a group purchase, one or more bottles, corresponding to at least one dye. The second product comprises on the one hand insoluble elements, mineral and / or synthetic, forming a charge and secondly different additives such as thickener, antioxidants, biocides. In addition, this second product contains a coalescing agent suitable for promoting the joining of water particles, as will be explained below. Example of a composition of such a product • calcium carbonate: 26%

• titanium oxide: 8%

• cellulosic thickener: 0.6%

• acrylic resin: 14%

• biocide: 0.4% • coalescence agent: 1%

• micronized silica: 50%

Total: 100%

The biocide is the one described above.

A quantity of pulp containing 7.5% of this pulverulent composition, diluted in 2.5% of water, is prepared, preferably in the factory, by careful mixing until a paste having a viscosity of about 20,000 centipoises. To coat a square meter of surface, it takes about 1 kilo of paste of the second product. This second product is applied to the first product when it is dry. The implementation of the coating which has just been described is obtained by proceeding as follows

It may be necessary to prepare the surface to be coated after cleaning to remove relatively greasy dust and deposits that would greatly affect the coating. If the clean surface to be coated is matte and absorbent, the coating is applied directly, namely first an absorbent layer formed from the dough constituting the first product.

If, on the contrary, the surface has a satin or gloss coating, it is slippery, which is not conducive to the attachment of the first absorbent layer, in which case it begins by breaking the continuity of the coating, which is achieved easily with sandpaper or with a tool that claw, lacerate or perforate, then apply an underlayer of a product providing a granite surface, non-smooth, for example a coating containing a granular filler such as silica crushed to a particle size corresponding to the surface roughness desired. When the first product is in place, directly on the surface to be coated or on an underlay, it is allowed to dry for a few hours. The duration of drying obviously depends on the conditions prevailing at the place where the coating is applied.

With average temperature and humidity conditions, it takes 24 to 48 hours to achieve complete drying.

The application is made in a single pass, preferably manually, with the trowel to create irregularities in the absorbent layer, similar to those observed on the old walls covered with a thick layer, usually plaster, there where the regularity of the coating was of no importance and where the main thing was to do the work yourself, without calling a professional, and as soon as possible. But it is precisely this warm aspect that is often sought to give more charm and personality to monotonous and flat, usual and anonymous surfaces. When the first product is dry, it is hard and the evaporated water has released spaces in the absorbent mass.

The second product, which is also a paste containing water, is then applied. The application is also done in one pass, manually trowel and this application is more or less finely depending on the desired effect. If irregularities have been created in the first product (the absorbent layer), respect them by applying the second product in a thin layer, which can be done by scraping the excess product slightly, which gives a stone appearance with their natural irregularities. As the first product is dry and absorbent and the second is a water paste, it is absorbed by the first product, under the effect of capillarity. This results in very fast drying, essentially by absorption. The presence of a coalescing agent promotes the joining of the water particles and further accelerates the drying of the topcoat which directly depends on the speed of absorption of water by the absorbent layer. The composition of the second product makes it possible to obtain an extremely hard and resistant topcoat that could be described as "liquid stone", because of its resistance to small impacts, scratches and friction for example, and also because his touch reminiscent of the polished stone. This hard layer can also be waxed and its touch is reminiscent of fine leather leather.

The coating has a particularly interesting and even surprising property with respect to the characteristics described above, especially the hardness, this property being that after having been applied, recently or for a long time, the coating can be easily removed by means of a simple wallpaper stripper.

Indeed, the stripper emits water vapor which easily passes through the topcoat and reaches the absorbent layer. Indeed, the topcoat consists of the second product which is derived from a paste with water and it softens, dissociates and strips the absorbent layer which itself comes from a paste with water, is penetrated by the steam, disunites and loses its adhesion. The coating as a whole goes off in soft plates that are removed to eliminate them.

If the topcoat is coated with a varnish, it may form a barrier to the passage of steam, in which case it is necessary to break the continuity of the varnish before applying the wallpaper stripper, which the it is easily made with sandpaper or with a tool that scratches, lacerates or perforates the varnish.

The irregularities of the absorbent layer may simply result from deliberately clumsy handling of the trowel but one can also create irregularities, or more precisely, discontinuities, by applying removable elements on the surface to be coated itself. It may be, for example, specific signs such as letters, numbers, symbols or graphics. It can also be simple straight lines, broken or curved depending on the desired effect.

These removable elements can be adhesive parts, the word "part" being taken in its widest sense and covering including adhesive tapes.

After having placed these removable elements regularly or not, the first product is applied and allowed to dry, then removing these removable elements which leave traces of hollow relative to the reliefs due to the thickness of the first product. The second product is then applied to the assembly so that it covers both the first product and the depressions.

The hardness of the topcoat is such that the wall covering takes the place of tiles without noticeable lowering of quality, not only with respect to resistance to mechanical stresses but also with regard to hygiene and cleanliness since the cleaning of the topcoat is comparable to that of tiles or plastic, especially if we complete the topcoat with a protective coating such as a varnish. Preferably, the topcoat is smoothed after a beginning of drying, that is to say after only a few minutes, with a flat and polished face of a roller.

The roller allows manual polishing (circular polishing action of small amplitude about 20 cm ² ) of the second product on the absorbent base, the latter having been spread beforehand using a trowel. The finish with the roller makes it possible to tighten the particles of white or colored marble powder (carbonate of calcium) and makes it possible to obtain a very soft finish, very fine and very hard to the touch (similar to the marble or the stone).

The Exhibitor realized that all the rollers do not work and that the quality of their sanding is decisive in the quality of the finish. The finishing roller must, in general, have a sufficiently smooth polishing plane so as not to tear off the second product during the polishing action, and hard enough not to be scratched by the calcium carbonate particles. . More specifically, the roughness of the polishing surface determines the quality of the finish of the coating.

The roughness can be characterized by many criteria well known to those skilled in the art and measured according to standards established by standardized measuring instruments. These instruments are contact systems consisting of a feed unit and a probe that scans the part in a given direction, and a base length. Measurements begin with the acquisition of a profile, to which mathematical formulas are applied to extract different parameters.

Depending on the profile chosen, the asperities and the (or) filters applied, it is possible to obtain different results: the average height of the different projections, the height of the largest projection, the greatest amplitude between the height of a projection and the depth of a hollow, or the number of projections that exceed a certain threshold, etc. Each formula gave rise to a unit of measure. For example, the average roughness difference, Ra, is the arithmetic mean of all the ordinates of the profile in a base length, the average profile height, and the total roughness,

Rt, is the distance between the highest projection and the lowest hollow over the entire base length.

These parameters are brought together in two international standards: ISO 4287 and ISO 12085.

Compared with the parameters Ra and Rt, which have certain limits, in particular because they do not make it possible to differentiate the projections from the valleys, parameters associated with the lift ratio precisely define the shape of the roughness profile by calculating the percentage of material that we observe at different levels of the profile on the base length. This percentage is plotted on a specific curve called a curve Abbot-Firestone that defines the actual shape of the profile. The parameters Rpk, Rk and Rvk which make it possible to describe the curve are described in the standard ISO 13565-1 and -2.

The Abbot curve is divided into three horizontal zones that allow to calculate these parameters: an upper zone, a median zone and a lower zone.

The parameter Rk, which corresponds to the median zone, is correlated with the depth of the active part of the surface: after an initial phase of friction during which the projections - corresponding to the upper zone and represented by the parameter Rpk - are worn, this active part of the surface bears the load and comes into closer contact with the wall covering surface. Rk therefore corresponds to the depth of the clipped profile.

The parameter Rvk, which corresponds to the lower zone, represents the average depth of the valleys exceeding the central part of the profile, and the parameter Rpk represents the average height of the protrusions exceeding the central part of the profile.

Parameters MR1 and MR2 are the bearing length ratios determined on the cutoff lines that separate the clipped profile respectively from the salient peaks and deep valleys.

Surprisingly, the Applicant has found that a roller having a surface whose Rk is between 0.35 microns and 6 microns has a satisfactory result of finishing the coating.

Specifically, a roller having a surface whose Rk is between 0.55 microns and 1 micron has a particularly satisfactory finish of the coating.

The measurements were carried out on different rollers in an air-conditioned room at 20 ^° C. ± 1 ° C. with a roughness tester No. CTE-PROF-01 valid until July 2006, a roughness standard No. CTE RUG 03 (No. 7314/96 series) and a COFRAC B111137-1 calibration certificate valid until January 2007. The pebbles used are:

^» A" natural "1 pebble made of carrara marble cut from a diamond disc and then polished for about five minutes with diamond discs with finer and finer grit, ^» a "natural" 2 pebble made of carrara marble cut from a diamond disc then polished for about ten minutes with increasingly fine grain diamond discs, ^" an aluminum alloy pebble made of AS13Y30 alloy polished with a fine grain for about five minutes, a ceramic" mulite "pebble whose cut, shaping and polishing together took about 20 minutes, and

"a ceramic" alumina "roller whose cutting, shaping and polishing took together about 30 minutes.

The alloy AS13Y30 has the following chemical composition: Fe: = 0.70%

If: 11 to 13.5%

Cu: = 0.10%

Zn: = 0.15%

Mg: = 0.10% Mn: 0.30%

Ni: = 0.05%

Pb: = 0.10%

Sn: = 0.05%

Ti: = 0.15% Co: 0.20%

Al: the rest

Due to the presence of abrasive particles in the tadelakt coating, it is preferable to perform a surface hardening treatment, such as anodic oxidation, of the aluminum alloy roller. The best results were obtained by oxidation anodic having allowed the deposition of an oxide layer thickness greater than 10 microns.

The rollers used are similar to the roller 1 shown in FIGS. 1 and 2: an ergonomic gripping part 2 comprises a dome 3 adapted to be housed in the hollow of a hand and a holding groove 4 in which the push of the hand stalls. A second holding groove may be provided to wedge the little finger of the hand. The finishing part 5 comprises a flat active face 6 adapted to the polishing of the material.

The edges of the flat surface 6 are bevelled to form a chamfer 7 in order to avoid any scratching of the coating by the edges of the surface 6.

Each roller was previously cleaned and measurements were made according to ISO 4287, 12085 and 13565. Each roller has five measurements in five different directions and a base length of 5.6 millimeters (0.2205 inches). The value of each parameter given below represents the average of the five measured values for each parameter.

The values are reported in Table 1 below.

Then each roller was used for the finishing phase of the tadelakt-like coating whose composition was described above.

The process for obtaining the coating comprises a first step (i) of applying, on a building surface, an inner coating layer consisting of a first water-based paste comprising absorbent elements which are capable of absorbing water and which comprise in combination cellulose particles and vermiculite, a second step (ii) of drying of said inner layer by evaporation of the water it contains, a third step (iii) of application on said inner layer of an outer coating layer based on a second water paste, for obtaining said coating in which the water of said outer layer is absorbed in a reduced time by said absorbent elements, a fourth step (iv) of partially drying said outer layer by evaporation of the water it contains, and finally a fifth step

(v) finishing polishing the outer layer with the polishing roller by performing a circular motion of small amplitude of about 20 cm 2 until reaching a hard surface and smooth, similar to marble.

By partial drying is meant a drying of between 55% and 75%, 100% representing a total drying.

In order to accelerate this drying step, it is possible to press the outer layer with a trowel so as to penetrate the water of the outer layer into the inner layer.

In a particular embodiment of the process, the first paste is prepared by mixing the cellulose particles in water with a dry fraction of 5%, and the vermiculite particles with a dry fraction of 1%.

The first paste may further be prepared by slurrying calcium carbonate and glass fibers in water, such as fibers having a nominal diameter of less than 1 mm and a length greater than 2 mm. Generally, said inner layer and / or said outer layer are applied to the trowel.

The experiments show that, whatever the circumstances, the "natural" roller 1 always pulls the coating while the mulite makes it possible to obtain a satisfactory result when the movement is delicate. Thus, a roller whose planar active surface has a mean Rk parameter - corresponding to the average of the five Rk parameter measurements made according to ISO 13565-1 and -2 - less than 2 μm provides a satisfactory result. The pebble of polished aluminum alloy treated with anodic oxidation has a parameter Rk of less than 2 μm and, more precisely, of the order of 0.8 μm. It gives excellent results of polishing the material tadelakt way, significantly higher than those obtained with a pebble "natural 2" with a grade of 9/10 for the pebble aluminum alloy against 7/10 for the pebble "natural 2 ".

The surface heterogeneity is correlated in particular with the parameter Rt which represents the height between the highest peak and the deepest hollow of a roughness profile. The values given in Table 1 above show that even if the "natural" roller 2 has a parameter Rk close to that of the aluminum alloy roller, the "natural" roller 2 has a significantly higher Rt parameter (10). , 14 μm) to that of the aluminum alloy roller (3 μm).

Thus, such a difference in rating is attributed to a disparity of surface heterogeneity between the "natural" roller 2 and the aluminum alloy roller because the more homogeneous the surface, the easier the polishing and the constant result.

In addition, the surface heterogeneity of the natural rollers causes a long and tedious sanding to achieve a surface state compatible with polishing. Similarly, the average score obtained by the mulite pebble due to tearing of the coating in case of vigorous use is attributed to a relatively high Rk parameter, combined with the relative surface heterogeneity of this roller translated by a parameter Rt of about 8.5 microns. This explains why such a roller can be used effectively only for delicate work. These observations are reinforced by the results of the Rvk parameter measurements which show that a surface providing satisfactory results has a Rvk parameter of less than 1.4 μm, preferably less than 1.1 μm, typically less than 0.3 μm.

The alumina roller has a Rk parameter of less than 2 μm but provides poor polishing since it strips off a substantial part of the coating. But this tearing is produced by a suction phenomenon generated by a plane surface "too" smooth.

Thus, the Applicant has found that satisfactory polishing can not be obtained with a planar active surface having a parameter Rk less than 0.35 microns.

Consequently, the results of the parameter measurements Rk show that a surface allowing a satisfactory finish of the wall covering has a parameter Rk of between 0.35 μm and 2 μm, preferably of between 0.4 μm and 1.8 μm, moreover preferably between 0.45 μm and 1.7 μm, more preferably between 0.5 μm and 1.65 μm, more preferably between 0.55 μm and 1.4 μm, more preferably between 0.6 μm and 1.3 μm. more preferably between 0.6 μm and 1.2 μm, the best results being obtained for a parameter Rk of between 0.7 μm and 1 μm. However, a "natural" roller 2 whose planar active surface has been polished sufficiently to present a Rk parameter of less than 2 μm gives good results, but its surface is rapidly altered and may cause the coating to tear.

Thus, a "natural" roller 2 must be changed every 500 to 1000 m ^2, so that, for example, an AS13Y30 aluminum alloy roller does not have to be changed before more than 2000 m ² d 'use. Such a difference is explained by a difference in resistance to abrasion. This is measured by the Capon method according to the ISO 10 545-6 standard and expressed in volume of material removed: 630 mm ³ for the "natural 2" roller against 35 mm ³ for the aluminum alloy roller. Various tests show that a planar active surface exhibiting an abrasion resistance measured according to the ISO standard 546-6 of less than 500 mm 3 is compatible with the polishing of the tadlakt coating.

Another parameter makes it possible to distinguish the rollers having a surface state allowing a good polishing of the wall covering of the rollers having a surface state unfit for polishing: the ratio (MR2-MR1) / Rk, denoted subsequently "p".

Indeed, the best polishing results are obtained with rollers having a ratio p between 40 and 140, preferably between 60 and 110, the best results being obtained for a ratio p between 80 and 105. By way of example , the aluminum alloy roller has a ratio p of about 92.

Thus the rollers according to the invention make it possible on the one hand to substantially reduce the losses, the costs and the production time, in particular by avoiding the expensive and tedious step of selection and, on the other hand, to obtain a finishing by polishing the wall covering of the same or even better quality than that obtained with a natural pebble.

However, for reasons of cost of materials and / or convenience and waste limitation, it may be preferable to use a two-part roller as shown in FIG.

Such a roller 10 comprises a gripping portion 11 and a finishing portion 12 comprising the plane active surface 13, fixed to each other removably by a fixing 14 Velcro type.

The gripping portion may be chosen from an inexpensive material and / or easy to model such as for example plastic polymers, rubbers, wood, metal, ceramics, or any other material. The material of the at least one active surface may be chosen from aluminum alloy treated by anodic oxidation for a time sufficient to deposit an aluminum oxide layer greater than 10 μm, ceramics, glass, alloys, and the like. titanium or steel. Preferably, the edges of the edges of the flat surface are bevelled to form a chamfer 15 to avoid marking the wall covering by digging.

One or more rollers according to the invention may be sold with the wall covering in the form of a coating kit comprising the roller or rollers, a coating tank.

If the coating of the kit is a tadelakt-like coating as described above, the kit comprises the roller or rollers, an inner coating tank and an outer coating tank.

According to other characteristics of the invention: the means for fixing the gripping portion and the active planar face may be an adhesive allowing successive gluing and peeling, a snap fastener, a magnet, etc. .

Other surface curing methods may be used such as laser treatment, heat treatment, thermochemical treatment, anodic deposition, cathodic deposition, metallization, or other treatments which allow the surface to exhibit compatible roughness. with the finish of the coating and sufficient hardness to prevent the deposition of material on the coating and / or the alteration of the surface by the abrasive particles of the coating.

The process for obtaining the surface coating may also comprise, prior to step (i), a step of creating irregularities on said surface to be coated by applying removable elements, such as adhesive tapes, and between the steps (ii) and (iii), a step of removing said removable elements, to obtain following step (iii) reliefs and depressions.

In addition, after applying said inner layer in step (i) and before the latter is dry, fractions are removed prior to step (iii) where said outer layer is applied.

• The polishing instrument can have different forms: a form of roller whose active surface, removable or not, is under the handle, a form of trowel, a form of knife to coat, etc. The important thing is that the active surface has the characteristics according to the invention.

Claims

A wall coating polishing instrument produced by an industrial process having a gripping portion (2, 11) and a plane active surface (6, 13), characterized in that the planar active surface (6, 13) has a average parameter Rk, corresponding to the average of the five Rk parameter measurements made according to the standards ISO 13565-1 and -2, between 0.35 μm and 2 μm, preferably between 0.4 μm and 1.8 μm, still preferably between 0.45 μm and 1.7 μm, more preferably between 0.5 μm and 1.65 μm, more preferably between 0.55 μm and 1.4 μm, more preferably between 0.6 μm and 1.3 μm. more preferably between 0.6 μm and 1.2 μm, typically between 0.7 μm and 1 μm.

2. The instrument of claim 1, wherein the planar active surface (6, 13) further has a mean Rvk parameter, corresponding to the average of five Rvk parameter measurements made according to ISO 13565-1 and -2, lower e 1.4 μm, preferably less than 1.1 μm, typically less than 0.3 μm.

3. The instrument of claim 1 or 2, wherein the planar active surface (6, 13) further has a mean Rt parameter, corresponding to the average of five Rt parameter measurements made according to ISO 4287 and 12085, between 1 micron and 10 microns, preferably between 1, 5 microns and 5 microns, 2 microns and 3 microns.

Polishing instrument according to any one of the preceding claims, wherein the edges of the flat surface (6, 13) are bevelled to form a chamfer (7, 17).

A polishing instrument according to any one of the preceding claims, wherein the gripping portion (11) and the planar active surface (13) are releasably secured to each other by a fastening means (14). ).

Polishing instrument according to one of the preceding claims, wherein the gripping portion (2, 11) is taken in the group of handles in polymer, wood, metal and ceramic.

A polishing instrument according to any one of the preceding claims, wherein the material of at least the planar active surface is selected from the group consisting of metals, metal alloys, ceramics, glass, and thermoplastic materials. ;

Polishing instrument according to any one of the preceding claims, wherein the material of at least the planar active surface has undergone surface hardening treatment;

A polishing instrument according to any one of the preceding claims, wherein the material of at least the planar active surface is taken from the group consisting of the aluminum alloy treated by anodic oxidation for a time sufficient to deposit a aluminum oxide layer greater than 10 μm, ceramics, glass, titanium alloys and steel;

10. Polishing instrument according to claim 9, whose planar active surface (6, 13) is composed of an aluminum alloy AS13Y30.

11. Polishing instrument according to any one of the preceding claims, wherein the material of at least the planar active surface (6, 13) has an abrasion resistance expressed as a volume of material removed measured according to ISO 10 546-6 less than 500 cubic millimeters.

12. Building surface coating kit characterized in that it comprises: an internal coating tank which is intended to be applied to said surface and which consists of a first water paste comprising absorbent elements capable of to absorb water, an external coating tank which is intended to be applied to said inner coating layer after drying thereof and which consists of a second paste, said absorbent elements comprise in combination particles of cellulose and vermiculite, and a polishing instrument (1, 10) according to any one of claims 1 to 11.

The coating kit of claim 12, wherein said first paste comprises: cellulose particles in a dry fraction of 5%, and vermiculite particles in a dry fraction of 1%.

14. A coating kit according to claim 12 or 13, wherein said first paste and said second paste each comprise calcium carbonate.

The coating kit of claim 14, wherein said first paste comprises said calcium carbonate in a dry fraction of 50%.

16. A coating kit according to any one of claims 12 to 15, wherein said first paste further comprises glass fibers, such as fibers having a nominal diameter of less than 1 mm and a length greater than 2 mm.

17. Coating kit according to any one of claims 12 to 16, wherein said second paste comprises a coalescing agent capable of promoting the joining of the water particles.

18. A coating kit according to any one of claims 12 to 17, wherein said second paste comprises micronized silica.

19. A method for obtaining a building surface coating from the kit according to any one of claims 12 to 18, characterized in that it comprises the steps of:

(i) applying, on a building surface, an inner coating layer consisting of a first water-based paste comprising absorbent elements which are capable of absorbing water and which comprise in combination cellulose particles and vermiculite, (ii) allowing said inner layer to dry by evaporation of the water contained therein,

(iv) allowing said outer layer to partially dry by evaporation of the water it contains, then

(v) polishing the outer layer with the polishing instrument (1, 10) by performing a circular motion of small amplitude of about 20 cm ² until a smooth, hard surface is obtained to the touch, similar to marble.

The method of claim 19, wherein the first slurry is prepared by slurrying the cellulose particles in a dry fraction of 5% in water, and the vermiculite particles in a dry fraction of 1%.

21. The method of claim 19 or 20, wherein the first paste is prepared by further mixing in water calcium carbonate and glass fibers, such as fibers having a nominal diameter of less than 1 mm and a length greater than 2 mm.

22. Method according to one of claims 19 to 21, further comprising the steps prior to step (i), creating irregularities on said surface to be coated by applying removable elements, such as adhesive tapes, and - between steps (ii) and (iii), removal of said removable elements to obtain following step (iii) reliefs and valleys.

The method of one of claims 19 to 22, wherein after applying said inner layer to step (i) and before the latter is dry, fractions are removed prior to step (iii) where the said outer layer is applied.

24. Method according to one of claims 19 to 23, wherein said inner layer and / or said outer layer are applied to the trowel.