EP1180186B1 - Flexible polymer material sheet for stretched constructions, method for producing the same and false ceiling comprising this sheet - Google Patents

Abstract

A flexible sheet material of thickness less than half a millimeter for making tensioned structures such as false ceilings, in particular, the material including microprojections formed by displacing the material from which it is made, said material presenting an acoustic absorption coefficient which is higher than that of the same material without said projections.

Description

The invention relates to the technical field of sheet materials relatively thin, typically less than half a millimeter, used for the realization of under ceilings, false ceilings, false walls, wall coatings, by energizing these sheet materials.

We already know, in the prior art, a large number of achievements such materials, as well as their uses in false ceilings strained.

As examples, reference can be made to patent applications France published under the following numbers: 2 767 851, 2 751 682, 2 734 296, 2,712,006, 2,707,708, 2,703,711, 2,699,211, 2,699,209, 2,695,670, 2. 691,193, 2,685,036, 2,645,135, 2,630,476, 2,627,207, 2,624,167, 2,623,540, 2,619,531, 2,597,906, 2,611,779, 2,592,416, 2,587,447, 2,561,690, 2,587; 392, 2 552 473, 2 537 112, 2 531 012, 2 524 922, 2 475 093, 2 486 127, 2 523,622, 2,310,450.2 270,407, 2,202,997, 2,175,854, 2,145,147, 2,106,407, 2 002 261, 1 475 446, 1 303 930, 1 287 077. Reference can also be made to as examples, to the following documents: US-A-5,058,340, US-A-4,083,157, EP-A-643,180, EP-A-652,339, EP-A-588,748, EP-A-504,530, EP-A-338,925, EP-A-281 468, EP-A-215 715, EP-A-089 905, EP-A-043 466, WO-A-94/12741, WO-A-92/18722. Reference may also be made to requests for patent in France following from the plaintiff: 2,736,615, 2,756 600, 2,727,711, 2,712,325, 2,699,613, 2,695,670, 2,692,302, 2,658,849.

The materials known in the prior art for making false stretched ceilings or false stretched walls are most often materials polymers with many qualities such as: resistance fire, airtightness, dust, moisture, ease maintenance.

False ceilings obtained using such materials may incorporate thermal insulators, various spots or lighting, as well as ventilation or ventilation openings or sprinklers. Removable, they allow, if necessary, an intervention in the plenum.

Polymeric materials for stretch ceilings known in the art previous, translucent or opaque, tinted or unstained, matt, lacquered, marbled, suede or satin, can thus be used both in the middle in hospitals, for public facilities, laboratories or dwellings.

The lacquered finish allows a mirror effect often implemented in malls, a matte finish quite close to a plaster aspect being more usual to traditional decorations.

Despite their many advantages that led to their increasing use in various environments, false ceilings and false walls in canvas stretched polymer of the prior art have the major disadvantage of presenting poor acoustic properties, the reverberation of sounds on such stretch ceilings being particularly high.

The attenuation of the sound reverberation on the walls and ceilings is a technical problem in itself known for a long time.

Several technical solutions could be envisaged.

According to a first technique, soundproofing panels include a perforated metal or plastic plate attached to a support of mineral wool type or polyurethane foam. For this first Passive sound absorption technique using fibrous or porous materials, can refer, for example, to the following documents: EP-A-013 513, EP-A-023 618, EP-A-246,464, EP-A-524,566, EP-A-605,784, EP-A-652,331, FR-A-2 405 818, FR-A-2 536 444, FR-A-2 544 358, FR-A-2 549 112, FR-A-2 611 776, FR-A-2,611,777, FR-A-2,732,381, US-A-4,441,580, US-A-3,948,347. This technique leads to a set in which the counter-facing phonetically absorbing is integral with an apparent perforated facing. The perforations are intended to allow attenuation of the waves by the acoustic absorbent material, the latter can not be left visible because it is too fragile, sometimes messy and has a rough appearance unsightly.

According to a second technique, the panels forming the walls such that for example suspended ceilings are provided with cavities whose volume is calculated to tune them on certain frequency ranges, these cavities being protected by a porous facing. For this second type of technique, using Helmholtz resonators, one can see, for example, DE-PS-36 43 481, FR-A-2 463 235.

According to a third technique, employed in the field of suspended ceilings, the apparent surface of the ceiling panels is embossed or provided with grooves or deep cavities. We can refer to for example, FR-A-2 381 142, FR-A-2 523 621, FR-A-2 573 798, WO-A-80/01 183, WO-A-94/24382.

According to a fourth technique, honeycomb webs form absorbent membranes. This technique, expensive, is sometimes used in the recording studios.

US 3,782,495 discloses false ceilings acoustic slabs suspended comprising a metal foil or perforated plastic with removal of material, sheet stuck on a frame below a block sound insulating glass wool, the plastic sheet being able to be felted, coated, printed, dyed or colored to achieve a decorative effect.

EP 0 816 583 discloses a device for reducing the levels acoustics in buildings, with attenuation elements acoustically formed of several sheets located at a distance from one another and parallel to each other, suspended vertically, these sheets being rigid polymeric material such as polycarbonate or polyethylene, these sheets can be wound on a storage cylinder.

The document EP 0 399 935 describes an air distribution device, for heating, ventilation or air-conditioning purposes, the walls of the air distribution network being constituted by false ceilings made of stretched fabric at least partly permeable to the air for a pressure drop of about 1Pa for a nominal flow rate of 10 m ³ per hour per m ² of permeable surface.

Document DE 197 54 107C describes acoustic panels in polyester or metal such as steel or aluminum, placed parallel to each other others in suspension.

None of the technical solutions known in the prior art for the improvement of the phonic properties of walls or suspended ceilings is not adapted to the particular technique of ceilings or walls stretched.

A first object of the invention is to provide a flexible polymeric material, sheet, suitable for use in taut decorative structures, masking or display, such as in particular false ceilings, false walls, this material with greatly improved acoustic properties.

A second object of the invention is to provide a material such as this above, whose visual aspect remains perfectly adapted to its use, both in an industrial environment than in a hospital environment for equipment collective or modern or historic dwellings.

For these purposes, the invention relates, in a first aspect, to a polymeric material of flexible sheet, less than half a millimeter thick, for realization of tensile structures such as in particular false ceilings, this material having micro-reliefs extending from a height of a few microns to 100 microns and formed by embossing the material constituent of the material which thus has an acoustic absorption coefficient higher than the same material devoid of said reliefs.

• la hauteur des micro-reliefs, mesurée suivant une direction perpendiculaire au plan de ladite feuille au droit de ces micro-reliefs est inférieure à trois fois l'épaisseur de ladite feuille ;
• ses micro-reliefs forment des saillies sur une seule face de ladite feuille ;
• chacun de ses micro-reliefs est disposé suivant tes noeuds d'un motif régulier ;
• tous ses micro-reliefs sont disposés suivant les noeuds d'un seul motif, par exemple à maille carrée ;
• ses micro-reliefs forment des saillies sur les deux faces de ladite feuille, chacun de ses micro-reliefs étant disposé suivant les noeuds d'un motif régulier, tous ses micro-reliefs étant le cas échéant disposés suivant les noeuds d'un seul motif, par exemple à maille carrée ;
• ses micro-reliefs se présentent sous la forme de cuvettes dont le fond sensiblement plan est relié à l'ouverture par une bande de matériau d'épaisseur inférieure ou égale à celle des parties de la feuille séparant les micro-reliefs ;
• ses cuvettes sont de symétrie de révolution par rapport à un axe sensiblement perpendiculaire à leur paroi de fond ;
• la bande de matériau reliant la paroi de fond des cuvettes et leur ouverture est discontinue ;
• le matériau est pourvu de micro perforations, d'ouverture inférieure à quatre dixièmes de millimètre, au moins une partie des micro-reliefs étant pourvue desdites perforations, lesdites micro perforations étant le cas échéant également disposées entre les micro-reliefs ;
• les micro perforations sont disposées suivant les noeuds d'un motif ;
• les micro perforations sont disposées suivant les noeuds d'un motif identique à celui des micro-reliefs et décalé par rapport à celui ci ;
• les micro perforations sont obtenues par aiguilletage ou tout autre procédé équivalent ;
• les micro perforations sont obtenues sans enlèvement de matière ;
• le matériau est choisi parmi le groupe comprenant les chlorures de polyvinyle plastifiés, chlorure de vinylidène et copolymères chlorure de vinyle / chlorure de vinylidène ;
• la surface occupée par les micro-reliefs est comprise entre 0,5% et 10% de la surface de ladite feuille ;
• la densité de micro-reliefs et/ou de micro-perforations est comprise entre 2 et 60 par centimètre carré, de préférence 15 à 35 par centimètre carré, et plus particulièrement entre 20 et 30 par centimètre carré.

According to various embodiments, this material also has the following characters, possibly combined:

• the height of the micro-reliefs, measured in a direction perpendicular to the plane of said sheet at the right of these micro-reliefs is less than three times the thickness of said sheet;
• its micro-reliefs project on one side of said sheet;
• each of its micro-reliefs is arranged according to your knots of a regular pattern;
• all its micro-reliefs are arranged according to the nodes of a single pattern, for example square mesh;
• its micro-reliefs form projections on both sides of said sheet, each of its micro-reliefs being arranged along the nodes of a regular pattern, all its micro-reliefs being optionally arranged according to the nodes of a single pattern , for example square mesh;
• its micro-reliefs are in the form of cuvettes whose substantially plane bottom is connected to the opening by a strip of material of thickness less than or equal to that of the parts of the sheet separating the micro-reliefs;
• its cuvettes are of symmetry of revolution with respect to an axis substantially perpendicular to their bottom wall;
• the strip of material connecting the bottom wall of the cuvettes and their opening is discontinuous;
• the material is provided with micro perforations, opening less than four tenths of a millimeter, at least a portion of the micro-reliefs being provided with said perforations, said micro perforations being optionally also arranged between the micro-reliefs;
• the micro-perforations are arranged according to the nodes of a pattern;
• the micro-perforations are arranged according to the nodes of a pattern identical to that of the micro-reliefs and offset with respect thereto;
• the micro-perforations are obtained by needling or any other equivalent method;
• micro perforations are obtained without removal of material;
• the material is selected from the group consisting of plasticized polyvinyl chlorides, vinylidene chloride and vinyl chloride / vinylidene chloride copolymers;
• the surface occupied by the micro-reliefs is between 0.5% and 10% of the surface of said sheet;
• the density of micro-reliefs and / or micro-perforations is between 2 and 60 per square centimeter, preferably 15 to 35 per square centimeter, and more particularly between 20 and 30 per square centimeter.

According to a second aspect, the invention relates to a method of making a sheet of material as presented above, this method comprising a needling step, locally repelling the material constitutive of the sheet until its micro perforation, in a pattern predetermined. The needling step is carried out without the sheet being subjected to removal of material. The needles used in the process needling have an extreme diameter of less than one tenth of a millimeter, example of the order of four hundredths of a millimeter. In a mode of realization, the needling step is conducted while the sheet of material is placed under a voltage of the order of that of its end use in a tense structure.

The invention relates, in a third aspect, to a false ceiling, characterized in that it comprises a sheet of a material as presented herein above, energized relative to support means.

• les figures 1a, 1b et 1c illustrent différents modes de réalisations d'un matériau pour toile tendue selon l'invention ;
• la figure 2 est un graphe représentant les valeurs de coefficient d'absorption acoustique mesurées, en fonction de la fréquence moyenne tiers d'octave dans quatre conditions expérimentales 1b,2b,3 et 4, ainsi que pour un échantillon de référence étalon ;
• la figure 3 est un graphe analogue à celui de la figure 2, pour les conditions expérimentales 5, 6 et 7 ;
• la figure 4 est un graphe analogue à celui de la figure 3, pour les conditions expérimentales 8, 8b, 9, les résultats obtenus pour les conditions 1b, 2b étant reportées sur le graphe de cette figure 4 afin de comparaison ;
• la figure 5 est un graphe analogue à celui de la figure 2, pour la condition expérimentale 10, les résultats obtenus pour les essais 3, 6 étant reportés sur ce graphe de la figure 5, afin de comparaison ;
• la figure 6 est un graphe analogue à celui de la figure 2, pour la condition expérimentale 11, les résultats obtenus pour les conditions 4 et 5 étant reportés sur ce graphe de la figure 6, afin de comparaison ;
• la figure 7 est un graphe analogue à celui de la figure 2, pour les conditions expérimentales 12, 13 et 14 ;
• la figure 8 est un histogramme des valeurs de coefficient d'absorption sonore en fonction de la valeur de fréquence tiers d'octave, pour les conditions expérimentales A ;
• la figure 9 est un histogramme analogue à celui de la figure 8, pour les conditions expérimentales B ;
• la figure 10 est un histogramme analogue à celui de la figure 8, pour les conditions expérimentales C.

Other objects and advantages of the invention will become apparent from the following description of embodiments, which description will be made with reference to the appended drawings in which:

• FIGS. 1a, 1b and 1c illustrate various embodiments of a stretched canvas material according to the invention;
• Fig. 2 is a graph showing the measured sound absorption coefficient values, as a function of the average third octave frequency in four experimental conditions 1b, 2b, 3 and 4, as well as for a reference standard sample;
• Figure 3 is a graph similar to that of Figure 2, for the experimental conditions 5, 6 and 7;
• FIG. 4 is a graph similar to that of FIG. 3 for the experimental conditions 8, 8b, 9, the results obtained for the conditions 1b, 2b being plotted on the graph of this FIG. 4 for comparison;
• FIG. 5 is a graph similar to that of FIG. 2, for experimental condition 10, the results obtained for tests 3, 6 being plotted on this graph of FIG. 5, for comparison;
• FIG. 6 is a graph similar to that of FIG. 2, for experimental condition 11, the results obtained for conditions 4 and 5 being plotted on this graph of FIG. 6, for comparison;
• Figure 7 is a graph similar to that of Figure 2, for the experimental conditions 12, 13 and 14;
• Fig. 8 is a histogram of the sound absorption coefficient values as a function of the third octave frequency value, for the experimental conditions A;
• Fig. 9 is a histogram analogous to that of Fig. 8 for experimental conditions B;
• FIG. 10 is a histogram analogous to that of FIG. 8, for experimental conditions C.

We first refer to Figure 1.

FIG. 1a is a front view of a material 1 of thickness of the order one-tenth of a millimeter, provided with substantially identical micro-reliefs 2 regularly distributed on a network with square mesh. In Figure 1b is shown in greatly enlarged view the shape of these reliefs 2, when seen in perpendicular to the plane of figure 1. The dimensions of the micro reliefs are such that they appear almost punctual in Figure 1. These reliefs 2 are present, in the embodiment considered here, in the form of cups substantially of revolution shape around an axis 3 perpendicular to the middle plane of the sheet of material 1 laid flat. These reliefs extend over a shallow height h, of the order of a few microns to a few tens of microns, and have an apparent aperture of the order of two tenths of a millimeter.

In the embodiment shown, these micro reliefs are provided a bottom wall 4 with a hole. These through holes 19 are derived, in a particular embodiment, needling with needles whose tips have a diameter of the order of a few hundredths of a millimeter, for example 4 hundredths of a millimeter.

In one embodiment, this needling is performed while the sheet of material 1 is energized. This tension is, in one embodiment particular, of the order of that suffered by the leaf at its place of use, by example in a suspended false ceiling.

The holes through 19, of diameter of the order of a few hundredths millimeters, are obtained without removal of material.

The bottom wall 4 of the micro-perforated reliefs 2 is connected to the edge of the cups by an annular wall 5 of revolution about the axis 3. The case where appropriate, this wall 5 may have a thickness e5 less than that e1 measured between the reliefs for the sheet of material 1. This difference thickness will be even more marked than the height h micro-reliefs 2 is important, given thickness e1.

In certain particular embodiments, not shown, for at least a portion of the reliefs 2, the annular wall 5 is discontinuous.

Alternatively, the bottom wall of at least a portion of the micro reliefs can be substantially full, that is to say devoid of through hole.

• pas p entre les micro-reliefs : 1 mm ;
• densité de micro-reliefs, par centimètre carré : 25 ;
• hauteur des reliefs : de quelques microns à 100 microns.

By way of example, the following values can be implemented:

• not p between micro-reliefs: 1 mm;
• density of micro-reliefs, per square centimeter: 25;
• height of the reliefs: from a few microns to 100 microns.

Other embodiments may be envisaged.

According to a first type of embodiment variant, the reliefs are not all identical, two or more populations of landforms that can be distinguished, these reliefs being of different shapes.

According to a second type of embodiment variant, possibly combined with the first type above, the reliefs are not all substantially punctually, but extend along at least one direction to form micro grooves and micro grooves.

According to a third type of variant, possibly combined with one or both types above, all the reliefs are not symmetrical to revolution with respect to an axis substantially perpendicular to the mean plane of the sheet of material 1.

So, for example, the bowl bottoms, when seen in plan, can be square, rectangular, oval, shaped like a regular polygon or not. The mesh of the network of micro-reliefs is square, in the embodiment of In other embodiments, this mesh is not square. but rectangular.

In some embodiments, at least two micro-relief networks, of mesh and / or not p1, p2, p'2 different are arranged on the sheet of material 1, as shown in Figure 1c.

Depending on the density of micro-reliefs, the pattern of their distribution, of their height, the inventors found that the visual impact of the implementation these reliefs are more or less marked, as is the impact on the acoustic properties of the sheet of material 1, an improvement spectacular acoustic properties that can be achieved without noticeable visual impact, the realization of micro-reliefs perforated micro-reliefs especially all at once effective in terms of acoustics and almost undetectable to the look. While keeping a conventional aspect of stretched canvas, clearly demarcating perforated suspended ceilings or mesh, the invention makes it possible in particular to achieve acoustic properties similar to suspended noise ceilings.

In some embodiments, as mentioned above, the sheet is provided with micro-reliefs but is not perforated or micro-perforated. The fact of realize micro-reliefs, without perforations, allows to improve the properties acoustic properties of the material without affecting its barrier properties fluids. Compared to perforated sheets, any traces of passage such as dark markings can also be avoided. Similarly, perforations with irregular edges obtained when the perforation tool is worn can be avoided. The material is also easily washable.

When a sheet of material with micro perforations is seen according to the arrow F of FIG. 1b, the micro-perforations 19 do not alter substantially its visual appearance. The inventors have notably found that the production of micro-perforations 19 as represented in FIG. 1b is almost undetectable when combined with a matte finish for the visible side 20 of the material sheet 1. The improved acoustic properties for the material prevent the introduction of fibrous insulation, which can generate dust and microfibers whose impact on health could be discussed.

The improvement of the acoustic properties of the sheets of material, by implementation of micro-perforated micro-reliefs will now be illustrated in using some experimental results. Before presenting these results, the following acoustics should be recalled, as long as these elements are not in the field of knowledge of the person skilled in the art ceilings and walls in stretched canvas.

The sound waves are derived from the propagation of pressure variations in the elastic media, by wave fronts, at a rate depending in the solids, of the modulus of elasticity and the density of the solid (of the order of 500 m / s in a cork and 3100 m / s in a common concrete for example). The spectrum audible by the human ear is formed by the frequencies of the vibrations of the sounds between 16 Hertz and 20 000 Hertz, when these sounds are emitted beyond a certain acoustic pressure (threshold of audibility equal to four phones). The frequency domain of the speech is between 10 and 10 kHz approximately, understandable speech being focused on frequencies between 300 Hz and 3 kHz. The domain of musical frequencies is between about 16Hz and 16kHz, an octave corresponding to a doubling of frequency. Instrument or voice Low frequency (Hz) High frequency (Hz) Violin 200 3000 Piano 30 4000 Flute 250 2500 Cello 70 800 Bass 40 300 Tuba 50 400 Trumpet 200 1000 Organ 16 1600 Low 100 350 Baritone 150 400 Tenor 150 500 Alto 200 800 Soprano 250 1200

• les matériaux poreux rigides, tels que bétons poreux et mousses rigides, dans lesquels les réseaux de capillaires forment résistance acoustiques ;
• les matériaux poreux élastiques tels que laines minérales, feutres, polystyrènes, dans lesquels l'énergie acoustique est dissipée par friction solide ;
• les matériaux à résonance acoustique, agissant selon le principe des résonateurs d'Helmholtz, tels que panneaux perforés ;
• les matériaux à résonance mécanique, fonctionnant sur la base de l'oscillateur amorti.

The sound absorption can be obtained by converting acoustic energy into deformation work or internal friction in a porous absorbent material of low acoustic impedance, or by means of dissipating resonator, in the form of heat by internal friction, the acoustic energy of the sounds of frequencies close to the eigenfrequencies of the resonator. In a conventional manner, there are four types of phonic insulators:

• rigid porous materials, such as porous concretes and rigid foams, in which the capillary networks form acoustic resistance;
• elastic porous materials such as mineral wools, felts, polystyrenes, in which acoustic energy is dissipated by solid friction;
• acoustic resonance materials, acting on the principle of Helmholtz resonators, such as perforated panels;
• mechanical resonance materials, operating on the basis of the damped oscillator.

An absorption index of sounds α (without units) is defined, this index α being the normalized difference of the incident and reflected acoustic energy. This index depends on the frequency of the incident sounds. As the sound attenuation in air is a function of temperature, pressure and relative humidity, the measurements of the absorption index must be carried out at known temperature, pressure and humidity (see French standard NF S 30,009). With regard to the measurement standards of this index, reference may be made, for example, to the following documents: international standard ISO 354, French standard NF EN 20354, NF S 31 065, standard ASTM C423 of the United States of America. The table below gives some values of this sound absorption index α. α
for 125 Hz α
for 500 Hz α
for 2000 Hz Rough on masonry 0.02 0.02 0.03 Crimped with lime 0.03 0.03 0.04 Lightweight concrete 0.07 0.22 0.10 Mortar 0.03 0.03 0.07 Acoustic plate thickness 2.5 cm with 3 cm of air 0.25 0.23 0.74 drawn on a wall 0.15 0.23 0.73 Insulating panels thickness 2 cm applied on a wall 0.13 0.19 0.24 with 3 cm of air 0.15 0.23 0.23 with 3 cm of glass wool 0.33 0.44 0.37 wood door 0.14 0.06 0.10 parquet 0.05 0.06 0.10 plywood 3mm air 2cm 0.07 0.22 0.10 plywood 3 mm on a wall 0.07 0.05 0.10

In the same way, a reflection index of the sounds p, an index sound dissipation δ and a sound transmission index.

At the interface between two environments, the principle of conservation of energy acoustic implies that: ρ + τ + δ = 1, ρ + α = 1.

The more acoustic energy dissipated by acoustic insulation is large, minus the reflected acoustic energy will be high, decreasing the effect echo.

The echo or reverberation due to the reflection of sounds on an obstacle generates interference that can greatly increase the noise level in a local and make conversations difficult to follow.

For this reverb, we define a reverberation time T, according to Sabine's formula T = 0.163 V / αA where V is the volume of the free space; A is the absorbent surface; α is the absorption index defined above.

This formula of Sabine is established on the assumption of a perfectly homogeneous distribution of the reverberated field. Time to reverberation is the time after which the acoustic energy has decreased by 60dB, ie 1 ppm compared to its initial value.

These notions of acoustics having been recalled, will be presented here. below some experimental results obtained in conditions standardized.

In a first series of tests, twelve strips of material made the subject of sound absorption tests.

The sheets of material, of dimensions 9'x8 'were fixed on the surface of a parallelepiped box of glass wool, with a thickness of wall 3/4 ', dimensions 9'x8'x4', the box being placed on a plate in corrugated steel.

The glass wool box was removed from the room reverberation for the so-called empty chamber measurements. The results of tests are given in Table I below.

The frequencies mentioned in Table I are the center frequencies of the normalized third octave bands. First series of tests Frequencies (Hz) Test 1b Test 2b Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Test 10 Test 11 Test 8b 125 0.43 0.71 0.77 0.77 0.37 0.43 0.47 0.80 0.46 0.33 0.42 0.90 160 0.31 0.70 0.68 0.60 0.43 0.45 0.49 0.97 0.59 0.61 0.59 1.01 200 0.18 0.69 0.69 0.66 0.41 0.41 0.40 0.89 0.42 0.49 0.55 0.93 250 0.21 0.63 0.73 0.72 0.49 0.51 0.43 0.88 0.51 0.63 0.61 0.97 315 0.29 0.79 0.87 0.88 0.68 0.73 0.65 0.90 0.70 0.79 0.75 0.94 400 0.39 0.87 1.00 1.03 0.81 0.83 0.70 0.82 0.76 0.83 0.83 0.76 500 0.41 0.82 1.02 1.03 0.82 0.85 0.70 0.75 0.74 0.92 0.93 0.69 630 0.39 0.73 0.98 0.99 0.87 0.87 0.68 0.69 0.69 0.91 0.90 0.65 800 0.37 0.69 1.00 1.00 0.93 0.93 0.67 0.68 0.68 0.94 0.93 0.67 1000 0.34 0.61 1.01 1.00 0.97 0.99 0.61 0.63 0.60 0.95 0.93 0.67 1250 0.35 0.58 1.06 1.06 1.02 1.04 0.59 0.61 0.57 1.01 1.00 0.62 1600 0.37 0.56 1.09 1.09 1.05 1.07 0.54 0.57 0.53 1.02 1.00 0.59 2000 0.35 0.48 1.08 1.04 1.07 1.07 0.50 0.50 0.44 0.97 0.97 0.52 2500 0.34 0.43 1.07 1.01 1.07 1.07 0.44 0.43 0.34 0.91 0.88 0.49 3150 0.30 0.36 1.01 0.91 1.01 1.01 0.38 0.36 0.24 0.76 0.70 0.45 4000 0.27 0.32 0.93 0.78 0.97 0.98 0.37 0.33 0.10 0.57 0.46 0.43 CAA 0.35 0.65 0.95 0.95 0.85 0.85 0.55 0.70 0.55 0.85 0.85 0.70

The conditions of these tests are presented in Table II. Experimental conditions for the first series of tests Test number Sheet type support Sona Spray Acoustical Finish coating from K13 Spray-On Systems Fiberglass from Owens Coming on steel plate 1b Smooth Steel plate No No 2b Smooth Steel plate No 6 "R19 3 Perforated NLM41 Steel plate No 6 "R19 4 Perforated NL601 Steel plate No 6 "R19 5 Perforated NL601 Steel plate 1 " No 6 Perforated NLM41 Steel plate 1 " No 7 Smooth Steel plate 1 " No 8 Smooth - No 6 "R19, 3" from the sheet 8b Smooth - No 3-7 / 8 "RA24 (1.5 #) to 5.75" from the sheet 9 Smooth Steel plate 2.25 " No 10 Perforated NLM41 Steel plate 2.25 " No 11 Perforated NL601 Steel plate 2.25 " No

The leaves called "perforated NLM41" are of the type of those sold by the Applicant under the reference NewLine NLM41. These sheets are provided with large perforations (holes diameter of four millimeters), obtained by removal of material, the hole density being less than one per square centimeter. These circular holes are intended to allow ventilation of the plenum and a possible smoke extraction: this range of NLM41 products is classified M1 / B1 / Fire 1.

The sheets called "perforated NL601" are of the type of those sold by the applicant under the reference NewLine NL601. These leaves are also provided with large perforations (holes circular diameter of one millimeter), perforations obtained by removal of matter. These circular holes are intended, just like those of the leaves NLM41, to allow ventilation of the plenum and possible smoke extraction, this range of NL601 products being classified M1 / B1 / Fire 1.

• la figure 2 donne les résultats pour les essais 1b, 2b, 3, 4, par rapport à cinq valeurs obtenues pour un étalon de référence ;
• la figure 3 donne les résultats pour les essais 5, 6, 7, par rapport audit étalon de référence ;
• la figure 4 est un graphe rassemblant les résultats des essais 8, 8b et 9, comparés à ceux obtenus pour les essais 1b, 2b, et 7 ;
• la figure 5 est un graphe représentant les résultats obtenus pour l'essai 10, comparés à ceux des essais 3 et 6 ;
• la figure 6 est un graphe représentant les résultats obtenus pour l'essai 11, comparés à ceux obtenus pour les essais 4 et 5.

The curves corresponding to these results are given in FIGS. 2 to 7:

• Figure 2 gives the results for tests 1b, 2b, 3, 4, compared to five values obtained for a reference standard;
• Figure 3 gives the results for tests 5, 6, 7, with respect to said reference standard;
• FIG. 4 is a graph summarizing the results of tests 8, 8b and 9, compared with those obtained for tests 1b, 2b, and 7;
• Fig. 5 is a graph showing the results obtained for test 10, compared to those of tests 3 and 6;
• FIG. 6 is a graph showing the results obtained for test 11, compared with those obtained for tests 4 and 5.

The comparison of curves 1b and 2b shows the impact of the implementation instead of conventional fibrous sound insulation, as can be done in the plenum.

The comparison of the curves 3 and 4 on the one hand with the curves 1b 2b on the other hand shows that the placement of perforations on the stretched sheet makes it possible to increase the sound absorption properties, in particular at the high frequencies, the domain in which the introduction of the fibrous insulation is not very effective. The inventors have sought an explanation for this observation. It turns out that, in the field of acoustics, it is known that a rigid perforated panel of thickness h situated at a distance e from a wall and comprising a number n of cylindrical perforations of radius a, this panel being supported by four orthogonal cleats, has a maximum efficiency pulse of ω = c (nπ / a 2 e (h + 8a / 3π)) 1/2 this panel behaves as a set of Helmholtz resonators, its maximum sound absorption value remaining dependent on the value of the damping coefficient and the perforation rate. This type of mechanism is implemented in perforated suspended ceilings.

In the case of the stretched cloths considered here, the leaves of stretched materials are likely to vibrate and are therefore not rigid and indeformable, in addition the thicknesses h are very small compared to phonic insulating panels, so that the model presented above does not can be used. Other models, known in the field of acoustics, aim at predicting the behavior of perforated diaphragm panels, account of the proper stiffness of the panel and the compression of the air in the back of the panel, as well as its flow through the perforations, which can play a dissipative role.

These very complex models could possibly be invoked with respect to the results obtained in the 3,4,5,6,10,11 tests.

Curves 5, 6 and 7 illustrate the impact of setting up a acoustic spray coating on stretched sheets. The effect of this coating is especially marked in high frequencies. Conversely, as the shows Figure 4, for a smooth stretched sheet, the placement of insulation fibrous (tests 2b, 8, 8b) or the placement of an acoustic coating in spray (tests 7 and 9) gives, for frequencies above 400 Hz, results lower than those obtained with perforated sheets with or without acoustic coating spray. In all cases presented by tests 1b, 2b, 3,4,5,6,7,8,8b, 9,10 and 11, the attenuation properties acoustics had a great dissymmetry between low frequencies and high.

The inventors have found that, unexpectedly, and without that a simple explanation can be invoked, the realization of micro-reliefs and micro perforations led to results as favorable as the making large perforations. The results obtained with micro-perforations are even better in the field of high frequencies, compared to those obtained by large perforations.

Essays 12, 13 and 14 illustrate these amazing results. The conditions of these tests were as follows: temperature = 70F (about 21.2 ° C.), humidity = 64%, atmospheric pressure. A sheet of micro-perforated material of 9'x8 'was tested in an assembly type E 1219. By "micro-perforated" is meant here, with reference to tests 12, 13 and 14, a sheet of PVC material of 17 hundredths of a millimeter of thickness, provided with micro perforations formed by needling, without removal of material, the needles used having an end diameter of the order of 4 hundredths of a millimeter, the density of micro perforations obtained being of the order of three per square centimeter, the perforations being distributed over a mesh as shown in FIG. 1a. The sheet was stretched on the upper face of a parallelepiped box unpainted wall glass fiber thickness of 3/4 ", with a volume equal to 10154.72 cu.ft. The results said to" empty chamber "were obtained without placing the box, the sheet of material being placed on a steel plate For these empty chamber tests, the T60 values correspond to the average reverberation times The Acoustic Absorption Coefficient (CAA) and the accuracies The values of NRC and AAC were obtained according to ASTM C423, while for test 12 a 6 "thick layer of polyester wool was obtained in accordance with ASTM C423-90a. R19 glass from Owens Coming was suspended in the box, 3.75 "from the stretched sheet of material For test 13, a 1" thick layer of RA24 fiberglass from Owens Corning was suspended in the box at 8.75 "of the sheet of material t For test 14, no material was placed in the box. Tests N ° 12 13 and 14. Sound absorption measurements using a reverberation chamber Freq. (Hz) Empty room T60 (s) Incert. % Test 14 T60 (s) Incert. % CAA Prev. Sabins / sq.ft Test 13 T60 (s) Incert% CAA Prec Sabins / Sq.ft Test 12 T60 (s) Incert. % CAA Prev. Sabins / Sq.ft 50 1.63 5 1.31 3.23 0.76 0.26 1.37 2.59 0.52 0.26 1.88 15.29 0.84 0.61 63 1.37 7.56 0.96 4.48 2.15 0.50 0.90 3.25 2.59 0.46 1.01 4.61 1.80 0.50 80 1.60 5.44 1.17 14.97 1.61 0.92 1.12 6.42 1.88 0.48 1.15 4.52 1.71 0.36 100 2.40 5.74 2.21 6.64 0.24 0.32 1.96 9.18 0.64 0.36 1.70 2.44 1.17 0.19 125 3.16 2.37 2.81 3.90 0.27 0.11 2.57 3.86 0.51 0.12 2.37 2.67 0.73 0.09 160 3.56 3.22 3.06 1.99 0.32 0.08 2.63 1.95 0.69 0.08 2.56 4.01 0.76 0.13 200 4.01 2.53 3.55 2.31 0.22 0.06 2.94 2.38 0.63 0.07 2.58 2.07 0.96 0.07 250 5.62 1.34 4.37 2.16 0.35 0.04 3.45 2.53 0.77 0.05 3.18 2.06 0.94 0.05 315 6.67 1.77 5.02 1.43 0.34 0.03 3.81 1.58 0.78 0.03 3.54 1.19 0.91 0.03 400 6.25 0.90 4.53 1.65 0.42 0.03 3.64 1.62 0.80 0.03 3.39 1.77 0.93 0.04 500 7.05 0.62 4.82 1.08 0.45 0.03 3.93 1.28 0.78 0.02 3.85 1.43 0.81 0.03 630 7.23 0.73 4.85 1.29 0.47 0.02 3.99 1.44 0.78 0.03 3.95 1.43 0.79 0.03 800 7.23 0.41 4.65 1.01 0.53 0.02 3.89 0.71 0.82 0.01 3.87 0.84 0.83 0.02 1000 7.17 0.45 4.47 1.06 0.58 0.02 3.85 0.59 0.83 0.01 3.88 0.93 0.82 0.02 1250 6.92 0.45 4.17 0.55 0.66 0.01 3.72 0.51 0.86 0.01 3.70 0.52 0.87 0.01 1600 6.25 0.34 3.83 0.61 0.70 0.01 3.50 0.49 0.87 0.01 3.49 0.61 0.88 0.01 2000 5.29 0.43 3.45 0.73 0.70 0.02 3.21 0.47 0.85 0.01 3.21 0.52 0.85 0.01 2500 4.06 0.49 2.90 0.41 0.68 0.01 2.76 0.42 0.80 0.01 2.76 0.59 0.81 0.02 3150 3.37 0.57 2.54 0.59 0.57 0.02 2.45 0.40 0.78 0.02 2.44 0.48 0.78 0.02 4000 2.80 0.48 2.23 0.46 0.63 0.02 2.17 0.36 0.72 0.02 2.17 0.48 0.72 0.02 5000 2.20 0.55 1.85 0.50 0.59 0.03 1.82 0.40 0.66 0.02 1.80 0.48 0.69 0.03 6300 1.67 0.38 1.48 0.44 0.54 0.03 1.45 0.39 0.62 0.02 1.43 0.44 0.68 0.03 8000 1.21 0.53 1.11 0.50 0.50 0.04 1.09 0.68 0.58 0.05 1.08 0.60 0.65 0.05 10000 0.89 0.78 0.83 0.85 0.51 0.09 0.83 0.61 0.58 0.08 0.82 0.64 0.70 0.08

The values of AAC and NRC obtained are given in Table IV below: Tests N ° 12 13 and 14, NRC and AAC values obtained NRC AAC Trial 12 0.85 0.87 Trial 13 0.8 0.8 Trial 14 0.5 0.51

The sound absorption values obtained during the tests 12,13 and 14 are shown on the graph of Figure 7, only the frequencies between 125 and 4000 Hz being taken into account, in order to ensure homogeneity presentation with the graphs of Figures 2 to 6.

The combination of a micro-perforated membrane with an insulator fibrous placed at a distance from the rigid wall makes it possible to obtain an attenuation homogeneous acoustics over the entire frequency range considered.

Tests carried out for the first and second series mentioned above implemented an acoustic chamber with fiber walls of glass, which does not correspond to the actual layout of stretch ceilings.

To better evaluate the impact of the presence of the sheet support tense on the overall sound attenuation properties, a third series of tests was carried out under the following conditions.

Test A:

8 'x 9' fiberglass panels with a total weight of 0.25psf, 1 "thick (density 3 Ib / cu.ft) surrounded by a tubular metal frame of 4 "in height and 1-1 / 2" in nominal thickness were directly attached on the base wall of the reverberation chamber (assembly A of the standard ASTM E 795).

These frames formed support for strips of smooth material stretched PVC

Test B:

8 'x 9' panels of smooth PVC (5mil) were placed using a harpoon / rail assembly at 4 "from the bottom wall of the reverberation chamber (E90 fitting of ASTM E 795).

The support frame of smooth PVC panels is made of metal tubes height 4 "and nominal thickness 1-1 / 2".

This frame is fixed from the outside on the base wall of the chamber of reverberation.

2 "thick fiberglass board (density 3 lb / cu.ft) being placed directly on the bottom wall of this chamber.

The total weight of this fiberglass panel is 0.49 psf, the PVC tape weighing 0.05 psf.

Test C:

8 'x 9' panels of smooth PVC (5mil) were placed using a harpoon / rail assembly at 4 "from the bottom wall of the reverberation chamber (E90 fitting of ASTM E 795).

The support frame of smooth PVC panels is made of metal tubes height 4 "and nominal thickness 1-1 / 2".

This frame is fixed from the outside on the base wall of the chamber of reverberation.

1 "thick fiberglass board (density 3 lb / cu.ft) being placed directly on the bottom wall of this chamber.

The total weight of this fiberglass board is 0.25 psf, the PVC tape weighing 0.05 psf.

The results obtained are shown in Table V below. Results obtained for tests AB and C. Sound absorption coefficient Sabins Trial A Sound absorption coefficient Test B Sabins Trial B Sound absorption coefficient Test C Sabins Test C 100 0.05 3.6 0.17 12.5 0.09 6.6 125 0.07 5.3 0.28 20.0 0.14 9.8 160 0.12 8.3 0.47 33.8 0.24 17.2 200 0.21 15.3 0.75 54.3 0.34 24.7 250 0.30 21.6 1.02 73.5 0.52 37.1 315 0.45 32.6 1.11 80.0 0.70 50.3 400 0.66 47.5 1.08 77.9 0.87 62.5 500 0.69 49.6 0.84 60.7 0.69 50.0 630 0.71 50.9 0.66 47.3 0.52 37.1 800 0.72 52.0 0.52 37.3 0.39 27.9 1000 0.74 53.3 0.42 29.9 0.30 21.3 1250 0.78 56.4 0.34 24.8 0.25 18.2 1600 0.83 60.1 0.30 21.3 0.28 19.9 2000 0.87 62.6 0.25 18.2 0.31 22.4 2500 0.92 65.9 0.22 15.7 0.25 17.9 3150 0.94 67.7 0.18 13.2 0.21 14.8 4000 0.98 70.2 0.15 11.0 0.18 13.3 5000 1.01 72.5 0.13 9.3 0.18 13.0

The average NRC and NRC values obtained for these AB and C tests are specified below in Table VI. NRC values obtained for tests AB and C. Test A Test B Test C NRC Medium 0.65 0633 0455 NRC 0.65 0.65 0.45

The values of the sound absorption coefficients have been obtained according to the terms of ASTM C 423-90a, by a Bruel analyzer Kjaer type 2133.

The histograms of Figures 8, 9 and 10 represent the evolutions sound absorption coefficients for frequencies between 100 and 5000 Hertz, for tests A, B and C.

Flexible polymeric sheet material with acoustic properties improved which has just been described is suitable to be used for structures tense decoration or masking such as in particular false ceilings, false walls.

This material can also be used for panels display, fixed or scroll type, the attenuation of the reverb to reduce the noise nuisance generated by these panels.

The visual appearance of the material is not significantly modified by the these micro-reliefs, this material remains perfectly adapted to a use in both industrial and hospital settings as well as for public facilities or modern or historic housing.

The acoustic properties obtained using these materials are quite comparable to those of conventional suspended ceilings, as shown in the table below, given as an indication. Comparison of the acoustic properties of a micro-perforated sheet according to the invention and conventional ceiling plates. Product 125Hz 250Hz 500Hz 1000Hz 2000Hz 4000Hz CAA Suspended ceiling plate (Armstrong) 0.23 0.32 0.40 0.87 0.74 0.83 0.55 Suspended ceiling plate b (Armstrong) 0.34 0.32 0.40 0.64 0.71 0.76 0.55 Suspended ceiling plate c (Armstrong) 0.33 0.31 0.53 0.68 0.62 0.52 0.55 New Matte micro-perforated stretch fabric (assai 14) 0.27 0.35 0.45 0.58 0.70 0.63 0.50

Claims (23)

1. Polymer material (1) in a flexible sheet of a thickness (e1) of less than a half-millimetre, for the production of stretched constructions such as in particular suspended ceilings, characterised in that it comprises micro-reliefs extending over a height (h) from a few microns to 100 microns, micro-reliefs (2) formed by embossing the constituent matter of the material (1) which thus has a higher co-efficient of acoustic absorption than the same material without said reliefs.
2. Material according to claim 1, characterised in that the height (h) of the micro-reliefs (2) measured in a direction perpendicular to the plane of the said sheet at the level of these micro-reliefs (2) is less than three times the thickness (e1) of said sheet.
3. Material according to claim 1 or 2, characterised in that the micro-reliefs (2) form projections on a single face of said sheet.
4. Material according to claim 3, characterised in that each of these micro-reliefs (2) is arranged following the nodal points of a regular pattern.
5. Material according to claim 4, characterised in that all these micro-reliefs (2) are arranged following the nodal points of a single pattern.
6. Material according to claim 5, characterised in that the pattern has a square mesh.
7. Material according to claim 1 or 2, characterised in that the micro-reliefs (2) form projections on both sides of said sheet.
8. Material according to claim 7, characterised in that each of these micro-reliefs (2) is arranged following the nodal points of a regular pattern.
9. Material according to claim 8, characterised in that all these micro-reliefs (2) are arranged following the nodal points of a single pattern.
10. Material according to claim 9, characterised in that the pattern has a square mesh.
11. Material according to any of claims 1 to 10, characterised in that these micro-reliefs (2) take the form of cups, the approximately flat base (4) of which is linked to the opening by a strip of material (5) of thickness less than or equal to that of the parts of the sheet separating the micro-reliefs (2).
12. Material according to claim 11, characterised in that the cups are symmetrical in revolution in relation to an axis (3) approximately perpendicular to their base wall (4).
13. Material according to claim 12, characterised in that the strip of material (5) linking the base wall (4) of the cups and their opening is discontinuous.
14. Material according to any of claims 1 to 13, characterised in that it is fitted with micro-perforations of opening less than four-tenths of a millimetre.
15. Material according to claim 14 characterised in that at least some of the micro-reliefs (2) are fitted with said micro-perforations.
16. Material according to claim 14 or 15, characterised in that the density of the micro-perforations is between 2 and 60 per square centimetre.
17. Material according to any of claims 1 to 16, characterised in that it is selected from the group comprising plasticized polyvinyl chloride, vinylidene chloride and co-polymers of vinyl chloride / vinylidene chloride.
18. Material according to any of claims 1 to 17, characterised in that the surface occupied by the micro-reliefs (2) is between 0.5% and 10% of the total surface of said sheet.
19. Process for production of a sheet of material as presented in any of claims 1 to 18, characterised in that it comprises a needling stage, locally embossing the constituent material of the sheet in a predetermined pattern until its microperforation.
20. Process according to claim 19, characterised in that the needling stage is produced without the sheet suffering a loss of material.
21. Process according to claim 19 or 20, characterised in that the needles used in the needling process have an extreme diameter of less than one-tenth of a millimetre.
22. Process according to any of claims 19 to 21, characterised in that the needling stage is carried out when the material sheet is placed under a tension of an order of that of its final use in the stretched construction.
23. Suspended ceiling, characterised in that it comprises a sheet of material as presented in any of claims 1 to 18, tensioned in relation to the support means.

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