Method for non-structural work, with plaster panels and coatings for filling and finishing seams

0001The present invention relates to the construction of second artwork. More particularly, the invention relates to any process of construction, according to which there is, on one hand, prefabricated plates, comprising a plaster body and at least one sheet of paper or cardboard facing, at least one outer layer has a front Outdoor apparent, ready to be decorated, and secondly, at least one complementary pointing coat which can be used in particular for the finishing of a joint. Then assembling said flat elements to each other, with the essential component sealing coat joints between different plates and the joints are finished with said complementary coat, applied to the sealing coat, so as to obtain a surface overall external and apparent, relatively uniform or plane, there including at the joints. Such a process is implemented by example to define spaces within a building, including partitions.

0002According to EP-A-0521804, the paper siding may have a top layer called upper jet, comprising white cellulose fibers, mainly chemical, and a mineral filler of light color, preferably white, and a pigment layer revêtissant the upper layer, comprising a mineral filler of light color, preferably white, and a binder.

0003In general, the overall surface, external and apparent, obtained according to the process defined above needs to be prepared, before receiving any surface decoration, whether one or more layers of a film coating, the type paint or lacquer, or whether a thickness of wallpaper. This preparation is made necessary, including the differences in color or existing color between the visible outer face of one hand plasterboard, and visible outer face of the other seals. this preparation consists, after termination of the second work, coating the surface Overall obtained, that is to say the face of the plates over the joints with one or more layers of a printing or coating or painting primer.

0004The preparation operation represents an additional cost, significant in a complete process of construction of a building for example. And yet, is not sufficient in some cases, get an overall surface decorated with uniform appearance, given by particular physico-mechanical differences remaining between the seals on the one hand and the plates on the other side.

0005The present invention aims to remedy the aforementioned drawbacks. More specifically, the invention relates to a construction process breaking with the traditional approach adopted to solve the problem discussed above, that is to say, removing the need for a preparation of the overall surface, before any decoration. However, the invention relates to a method which remains compatible with the practices of construction professionals, including those of the finishing work.

0006Furthermore, the method is more preferably characterized in that in addition to the absorption of surface water, at least one of following physical characteristics are homogenized or matched between plates and complementary coat, namely:<ul><li>the color or shade;</li><li>the surface appearance, the reflectance;</li><li>discoloration or coloration under the effect of light natural;</li></ul>

0007Advantageously, these different characteristics physical are defined as follows:<ul><li>the reflectance factor of the overall surface, including that of the outer visible surface of the joints, is between 70% and 80%, and preferably between 72% and 76%, for a wavelength of 457nm;</li><li>discoloration or coloration of the overall surface, including that of the visible outer face of the joints, a difference of color (delta E *) at most equal to 3 after exposure for 72 hours at a UV radiation source, positioned 15cm from the surface of wavelength of at least 290nm.</li></ul>

0008According to the present invention, the method differentiates from the traditional approach in that on the one hand, the structure and / or composition of the facing paper, and on the other hand, the composition of the additional coat are adjusted relative to each other, for obtain, in the dry state of the additional coat, an overall surface having a surface water absorption substantially homogeneous in practically the entire overall surface, including at the front Outdoor apparent joints.

0009For example, the surface water absorption of the surface Overall, including that of the outer face of the joints, is not less than to 60 minutes and / or is at most equal to 15g / m² according to the COBB test, to 23 ° C.

0010The present invention provides decisive advantages following, consecutive to homogeneity surface of the overall surface obtained according to the present invention, not only in terms of color or hue, but also in terms of certain physical characteristics or physico-chemical, including surface water absorption.

0011Thus, by homogenizing the surface absorption capacity facing paper and additional joint, an aspect can be obtained Almost perfect or the layers of paint, but also a membership almost uniform wallpaper which subsequently promotes its homogeneous detachment.

0012According to an advantageous embodiment of the invention, and a structure and / or composition, pre-existing, the facing sheet of paper, adjusting the composition of the coating complementary.

0013According to another variant of the invention, and in contrast to what above, to a pre-existing composition of complementary coat, it adjusts the composition of the facing paper.

0014In practice, by routine tests, the skilled competent knows adjust the structure and / or composition of a sheet of facing paper and / or the composition of a coating, so as to meet the technical principles defined above, such that the examples described below are in no way limiting.

0015The present invention will now be described with reference to prefabricated drywall. These plates are typically composed of a plaster cast body at the factory between two sheets of paper constituting both its face and its armature.

0016Usually, one of the sheets of paper used to make the drywall is dark in color, which can vary between a gray color and a chestnut color, since it is made of fibers cellulose which have not undergone treatment to particular purification. Conventionally, this paper says gray is made from chemical pulp not bleached, and / or mechanical pulp and / or thermomechanical pulp, and / or of semi-chemical pulp. By mechanical pulp is usually meant a pulp obtained entirely by mechanical means from various raw materials, essentially wood, which can be made by recovery of timber products such as old cardboard, kraft paper clippings and / or old newspapers. For dough thermomechanical pulp obtained by a heat treatment means followed by mechanical treatment of the raw material. Semi-chemical pulp, is meant a pulp obtained by eliminating the first material a part of its non-cellulosic components by means of a treatment chemical, and requiring a subsequent mechanical treatment to disperse fibers.

0017The other sheet has a visible face of said face to generally lighter in color than the gray sheet. For this lighter color, the layer or layers of this face are based on pulp chemical optionally bleached, composed of cellulose fibers recycled and / or new and / or optionally bleached mechanical pulp. By chemical pulp is meant a pulp obtained by eliminating the material first by a chemical treatment, as by cooking in the presence Suitable chemical agents such as sodium hydroxide or bisulfites, a very large proportion of its non-cellulosic components. when this Chemical treatment is completed by bleaching, is eliminated Much of the colored substances, and substances that might deteriorate with age and giving unpleasant yellow shades related to the presence, for example lignin.

0018In a preferred embodiment of the method of the invention and according to EP A 0,521,804, paper siding has a top layer called upper jet, including white cellulose fibers, mainly chemical, charge mineral light color, preferably white, and a layer pigment revêtissant the upper layer, also comprising a mineral filler of light color, preferably white, and a binder. In correspondence according to the present invention, the additional coat comprises a mineral filler of light color, preferably white, whose particle size is between 5 and 35μm.

0019The fineness of particle size of the mineral filler of the coating complementary provides a smooth surface corresponding to that of facing the plate. Too big size of the filler causes all surface defects, such as reverberation light radiation on the surface of the coating, different from that on the plate surface, resulting in differences in tone and brightness of the hue. Too large particle size also leads to differences physical aspect, related to differences in roughness between the plate and the coating.

0020The mineral filler represents preferably between 50% and 85% of the total weight of the complementary coat.

0021Furthermore, the coating may comprise a hydrophobic agent, example between 0.2% and 5%, and preferably between 0.5% and 3% by weight total of the coating, for example a silicone derivative. This agent enables including slowing the kinetics of drying of the coating, which promotes its non-cracking, but also its better resistance to the aggression of water vapor during removal operations Paper painted this without harming the good adhesion of paint or paper glue, on the overall surface, the apparent surface area of joints. In fact, the hydrophobic agent levels out power absorbent surfaces of the coating and the paper facing of the plate. Thus, all paints or paper adhesives applied to the surface Overall obtained unfamiliar absorption kinetics lag between the coating and the plate, which prevents the appearance of ghosts or hue of inhomogeneities.

0022The coating also comprises an organic binder dispersible in aqueous phase, in a proportion of between 1 and 20%, and preferably between 2 and 12% of the total weight of the coating Further, for example polyvinyl acetates and / or esters of acrylic acid. The choice of this binder is important because it should give the coating sufficient flexibility to withstand the mechanical stresses, and must submit both a tack for good hangs on the overall surface and good resistance to attacks of UV light.

0023In addition, there is provided in the composition of the coating agent of handling, particularly a water retaining agent and thickener, by example methylhydroxyethylcellulose, in a proportion of 1 to 15%, and preferably from 2 to 12% of the total weight of the coating complementary.

0024Finally, there may be included in the composition of the coating at least a glidant, in particular a clay, in the proportion of 0.1 to 2%, and preferably from 0.1 to 0.6% of the total weight of the coating complementary. These clays are preferably silicate derivatives and more preferably clays of the attapulgite.

0025Other components, such as biocides, dispersants, anti-foaming agents and pigments may also be incorporated in the composition of the coating in the usual manner.

0026The invention will be better understood by the following detailed example, given as indicative and not limiting.

0027We share similar gypsum board in Example 5 Document EPA O 521 804, which are assembled with a sealing gasket vector, for example, a seal coating sold under the trademark filed "PREGYLYS" ® Company PLATRES LAFARGE. The upper jet the cladding plate is obtained from 65% cellulosic fibers bleached chemical and 35% talcum and is covered with a layer pigment comprising, as mineral filler, 85% by weight of CaSO₄ , 2H₂O as needles of length between 3 and 5 microns, and as a binder, 10.3% by weight of styrene-butadiene copolymer. The sealing gasket then receives a thin layer of a coating complementary jointing according to the invention having the following composition:<ul><li>50 to 85% by weight of calcium carbonate, grain size from 5 to 35 microns, as mineral filler;</li><li>2 to 12% by weight of a binder comprising polyvinyl acetates and acrylic acid esters in aqueous dispersion;</li><li>0.5 to 3% by weight of a silicone derivative as a hydrophobic agent;</li><li>0.1 to 0.9% of a methyl hydroxyethyl cellulose derivative type; </li><li>0.1 to 0.6% of a slip agent attapulgite;</li><li>1 to 12% of another silicate derivative as an agent sliding complementary ;</li><li>0.1 to 5% of a polycarboxylic acid ammonium salt as dispersant;</li><li>0.001 to 0.015 iron oxide as a pigment;</li><li>0.1 to 0.3% of a preparation of N-formol and isothiazolinones as a biocide;</li><li>0.1 to 0.3% of a conventional anti-foaming agent;</li><li>Water qs 100%.</li></ul>

0028given weight percentages are based on the weight total of the coating, unless otherwise indicated.

0029For comparison purposes, standard plates only in accordance with the French standard NF P 72-302, and not comprising the upper ply and pigment layer defined above, are assembled with a coated gasket for plasterboard of the range coatings "PREGYLYS" ®, marketed by PLATRES LAFARGE.

0030The characteristics of the two surfaces together and formed are compared by applying the following tests:<sl><li>A - Degree of whiteness or reflectance factor R obtained according to standard NFQ 03038 with a wavelength of 457nm. this degree represents the ratio in percentage between the reflected radiation body and considered that of a perfect diffuser under the same conditions.</li><li>B - Surface water absorption, obtained for example by the COBB test. In this test, a ring defining a surface 100cm²is filled with distilled water at 23 ° C over about 10mm high. The water is left in contact with the overall surface forming the bottom of the ring for a minute, then the water is drained and squeezed surplus. Gain weight of the surface is then determined, and reduced to a surface 1m². Alternatively, depositing a drop volume of approximately 0,05cm³, of distilled water at 23 ° C on the surface. It is important that the drop is filed and not dropped a variable height which thereby the roughly crush, which would falsify the result. The time in minutes is representative of the surface absorption of the tested surface. </li><li>C - UV radiation resistance, obtained by exposing the overall surfaces, in a chamber having eight lamps high pressure mercury 400 watts each at a wavelength which is not less than 290nm. The surfaces are maintained at a 15cm away lamps and at a temperature of 60 ° C for 72 hours. The color deviations delta E * are measured on a spectrocolorimeter, according to the standard DIN 6174 at an angle of 8 °, D65 glossy specular included in the L *, a *, b * where L * is the luminance, a * represents the transition from green red, and b * represents the transition from blue to yellow. A point E * in this system, which is a function of L *, a *, b *, defines the colorimetry of a sample and the standard is measured relative to a reference point. Of Generally, a color deviation beyond 2 becomes discernible to the naked eye.</li></sl>

0031Test results (A) and (B) are shown in Table I and those of the test (C) in Table II below.<tables><table><tgroup cols="5"><tbody><row><entry namest="1" align="center" /><entry namest="2" nameend="3" align="center">standard overall surface</entry><entry namest="4" nameend="5" align="center">overall surface according to the invention</entry></row><row><entry morerows="1" align="left">Reflectance R (%)</entry><entry align="left">Plate</entry><entry align="right">50-60</entry><entry align="left">Plate</entry><entry align="right">72-76</entry></row><row><entry namest="2" align="left">coating</entry><entry namest="3" align="right">65-85</entry><entry namest="4" align="left">coating</entry><entry namest="5" align="right">72-76</entry></row><row><entry align="left">Absorption</entry></row><row><entry align="left">COBB (g / m²)</entry><entry align="right" /><entry align="right">19</entry><entry align="right" /><entry align="right">13</entry></row><row><entry morerows="1" align="left">Variant (min)</entry><entry align="left">Plate</entry><entry align="right">50</entry><entry align="left">Plate</entry><entry align="right">> = 60</entry></row><row><entry namest="2" align="left">coating</entry><entry namest="3" align="right">15</entry><entry namest="4" align="left">coating</entry><entry namest="5" align="right">> = 60</entry></row></tbody></tgroup></table></tables>

0032This shows that the overall surface according to the present invention is clearly more homogeneous than that of an assembly according to usual technique. Moreover, the more homogeneous absorption time of the overall surface enables a paint coverage less than that required with the plates and coatings traditional, and also promotes the painting.<tables><table><tgroup cols="5"><tbody><row><entry namest="1" align="center">before exposure</entry><entry namest="2" nameend="3" align="center">Standard</entry><entry namest="4" nameend="5" align="center">Invention</entry></row><row><entry morerows="2" align="left">Initial measurements of the passover</entry><entry align="left">L * =</entry><entry align="right">82.94</entry><entry align="left">L * =</entry><entry align="right">90.41</entry></row><row><entry namest="2" align="left">a * =</entry><entry namest="3" align="right">- 0.43</entry><entry namest="4" align="left">a * =</entry><entry namest="5" align="right">- 0.03</entry></row><row><entry namest="2" align="left">b * =</entry><entry namest="3" align="right">4.64</entry><entry namest="4" align="left">b * =</entry><entry namest="5" align="right">3.13</entry></row><row><entry morerows="2" align="left">Initial measurements of the initial joint measures</entry><entry align="left">L * =</entry><entry align="right">90,70</entry><entry align="left">L * =</entry><entry align="right">89,70</entry></row><row><entry namest="2" align="left">a * =</entry><entry namest="3" align="right">0.73</entry><entry namest="4" align="left">a * =</entry><entry namest="5" align="right">0.50</entry></row><row><entry namest="2" align="left">b * =</entry><entry namest="3" align="right">5.28</entry><entry namest="4" align="left">b * =</entry><entry namest="5" align="right">3.60</entry></row><row><entry morerows="2" align="left" /><entry namest="2" align="left">Deviation of color</entry><entry namest="3" align="right" /><entry namest="4" nameend="5" align="left">Deviation of color</entry></row><row><entry namest="2" align="left">Plate / Joint</entry><entry namest="3" align="right" /><entry namest="4" nameend="5" align="left">Plate / Joint</entry></row><row><entry namest="2" align="left">Delta E * =</entry><entry namest="3" align="right">= 7.87</entry><entry namest="4" align="left">Delta E * =</entry><entry namest="5" align="right">1</entry></row><row><entry align="left">UV exposure for 72 hours</entry><entry namest="2" nameend="3" align="right" /><entry namest="4" nameend="5" align="right" /></row><row><entry morerows="2" align="left">Measurements of the plate after exposure</entry><entry align="left">L * =</entry><entry align="right">81.10</entry><entry align="left">L * =</entry><entry align="right">90.38</entry></row><row><entry namest="2" align="left">a * =</entry><entry namest="3" align="right">0.69</entry><entry namest="4" align="left">a * =</entry><entry namest="5" align="right">-0.91</entry></row><row><entry namest="2" align="left">b * =</entry><entry namest="3" align="right">12,93</entry><entry namest="4" align="left">b * =</entry><entry namest="5" align="right">7.40</entry></row><row><entry morerows="2" align="left" /><entry namest="2" align="left">Deviation of color</entry><entry namest="3" align="right" /><entry namest="4" nameend="5" align="left">Deviation of color</entry></row><row><entry namest="2" align="left">Delta E * =</entry><entry namest="3" align="right">8.56;</entry><entry namest="4" align="left">Delta E * =</entry><entry namest="5" align="right">4.36;</entry></row><row><entry namest="2" nameend="3" align="left">very sensitive, more brown spots yellowing</entry><entry namest="4" nameend="5" align="left">sensitive yellowing</entry></row><row><entry morerows="2" align="left">Measures of the joint after exposure</entry><entry align="left">L * =</entry><entry align="right">88.90</entry><entry align="left">L * =</entry><entry align="right">89.17 0.50</entry></row><row><entry namest="2" align="left">a * =</entry><entry namest="3" align="right">0.91</entry><entry namest="4" align="left">a * =</entry><entry namest="5" align="right">0.50</entry></row><row><entry namest="2" align="left">b * =</entry><entry namest="3" align="right">3.83</entry><entry namest="4" align="left">b * =</entry><entry namest="5" align="right">3.19</entry></row><row><entry morerows="2" align="left" /><entry namest="2" align="left">Deviation of color</entry><entry namest="3" align="right" /><entry namest="4" nameend="5" align="left">Deviation of color</entry></row><row><entry namest="2" align="left">Delta E * =</entry><entry namest="3" align="right">2.32;</entry><entry namest="4" align="left">Delta E * =</entry><entry namest="5" align="right">0.67;</entry></row><row><entry namest="2" nameend="3" align="left">slight yellowing over a few brown spots</entry><entry namest="4" nameend="5" align="left">very low color difference</entry></row></tbody></tgroup></table></tables> This table shows that the color deviation before exposure to UV is much lower for an overall surface of the invention, that for an overall surface as obtained traditionally.

0033This table also shows that the evolution of the color difference after exposure to UV is much less in the surface assembly according to the invention than traditionally. Indeed, it is necessary that the color deviation before exposure and after exposure is as small as possible so that the overall surface does not give the impression to the naked eye being spotted, or covered with shade areas and different gloss.

0034This is not possible with an overall surface obtained with drywall and traditional products, but the very low deviation of the overall surface according to the invention enables overcome this drawback.