Acoustic panel

Abstract

Acoustic panels, grids for acoustic panels, suspended ceiling systems and a method for producing an acoustic panel, especially a man-made vitreous fibre (MMVF) panel, having a first major face and an opposite second major face, with the first major face comprising a facing with a surface coating. To provide high light reflection the coating comprises microspheres.

Claims

1. Acoustic panel, especially a man-made vitreous fibre (MMVF) panel, having a first major face and an opposite second major face, with the first major face comprising a facing with a surface coating, wherein the surface coating comprises microspheres, wherein the average diameter of the microspheres is in the interval of 10-200 μm; wherein the facing is a non-woven or a felt having an air permeability of 400-900 l/m.sup.2/s; wherein the surface coating includes pinholes.

2. Acoustic panel according to claim 1, wherein the microspheres are made of silica, ceramic or glass.

3. Acoustic panel according to claim 1, wherein the average diameter of the microspheres is in the interval of 10-120 μm.

4. Acoustic panel according to claim 1, wherein the panel is a MMVF panel having a density in the range of 40-150 kg/m.sup.3.

5. Acoustic panel according to claim 1, wherein the facing is based on glass fibres.

6. Suspended ceiling system comprising an acoustic panel according to claim 1 and a grid comprising a surface coating on surfaces visible in the installed state of the suspended ceiling, wherein the surface coating comprises microspheres.

7. Method for producing an acoustic panel comprising the steps of: providing an acoustic panel, especially a MMVF panel, attaching a front facing to a first major face of the panel, applying a surface coating on the front facing, wherein the surface coating comprises microspheres and pinholes, wherein the facing is a non-woven or felt having an air permeability of 400-900 l/m.sup.2/s and wherein prior to applying the surface coating, the surface coating is conditioned to have a viscosity of 20-40 s DIN CUP4.

8. Method according to claim 7, wherein the surface coating is applied using a low viscosity coating technique.

9. Suspended ceiling system according to claim 6 wherein the average diameter of the microspheres of the surface coating of the grid is in the interval of 10-200 μm.

10. Acoustic panel according to claim 1, wherein the microspheres include a pigment.

11. Acoustic panel according to claim 1, having an NRC value of at least 0.95.

12. Acoustic panel according to claim 1, wherein the facing is white with an L-value of at least 95.

13. A highly-reflective, low gloss acoustic panel comprising: a man-made vitreous fibre (MMVF) panel having a first major surface and a second major surface; a facing attached to the first major surface, the facing comprising a non-woven or a felt having an air permeability of 400-900 l/m.sup.2/s; and a coating applied to the facing, the coating including microspheres having an average diameter of 10-200 μm and pinholes, which collectively provide the panel with high light diffusivity and low gloss.

Description

(1) The invention will be described in the following by way of example with reference to the drawings in which:

(2) FIG. 1 is a sketch of a panel,

(3) FIG. 2 is a close-up photo of a coated surface,

(4) FIG. 3 is a photo of a coated surface,

(5) FIG. 4 is a sketch showing the principles in room acoustics, and

(6) FIG. 5 is a sketch showing the principles in sound absorption of acoustic panels.

(7) FIG. 6 is a sketch showing a ceiling system comprising an acoustic panel, as shown in FIG. 1, and a grid comprising a surface coating on surfaces visible in the installed state of the suspended ceiling.

(8) In the sketch of FIG. 1 is seen a panel (1) having a first major face (2) and an opposite second major face. The first major face (2) is provided with a facing, such as a non-woven or felt.

(9) Microspheres (3) of the coating can be seen in the close-up photo of FIG. 2. As can be seen a number of the microspheres are situated in the surface providing the optical effect and giving a high light reflection and robustness of the surface coating.

(10) FIG. 3 is a photo of the surface of the panel, and it can be seen that the coating covers the surface in a way to conceal any directional nature of the facing or subsurface. Further it can be seen that the surface is highly irregular and matt. Irregularity of the surface and the existence of small pinholes in the surface coating safeguards the acoustic performance of the panel.

(11) In the sketch of FIG. 4 is illustrated how the acoustic performance of a room is influenced by external sound sources, and further by sound in the room reflected by the floor, walls and ceiling.

(12) FIG. 5 shows how incident sound may be absorbed in an acoustic panel if the incident sound is allowed to penetrate into the panel through the first major face (2), whereas some of the sound may be reflected back into the room.

Scrub Testing

(13) A test to determine wet-scrub resistance of coated ceiling panels was carried out. Test samples were 430×110×6 mm panels of MMVF with a facing and coating including microspheres. The test was performed on an Erichsen scrub resistance tester in compliance with PN-EN ISO 11998:2007 requirements, however a soft PU sponge and not a brush, was used as a scrub body. The appearance of the coatings was assessed after 100, 200 and 500 cycles. Rating scale 1-5 was used to describe test results (1=Best, 5=Worst): Class 1—minute changes visible, Class 2—small thickness loss overall entire surface, no clearances to the surface, visible gloss loss, minute runs, Class 3—visible thickness loss and clearances to the surface, significant gloss changes and runs, Class 4—significant loss of a coating thickness and in some areas a panel surface becomes visible, Class 5—the panel surface damages (up to 100%).

(14) As can be seen in the table below the sample showed excellent scrub resistance.

(15) TABLE-US-00001 TABLE 4 Results after 100 Results after 200 Results after 500 scrub cycles scrub cycles scrub cycles Quality Quality Quality Sample Appearance class Appearance class Appearance Class Acoustic panel No changes 1 Shine, minute 2 Shine, minute 2 thickness thickness loss loss

Sound Absorption Test

(16) A sample measuring 1200×600×20 mm was tested for sound absorption according to BS EN ISO 354:2003 with very favourable results. Sound absorption coefficient of α.sub.w=1.00 was reached (Class A), calculated to EN ISO 11654:1997 and NRC 0.95 calculated to ASTM C 423-01.

Light Reflection Testing

(17) Measurement of light reflection of a sample of a panel provided with a coating with microspheres was performed. Spectral reflection was measured using a Perkin-Elmer Lambda 900 spectrophotometer equipped with an integrating sphere, geometry 8°/d. Reflection values, including and excluding specular components, was measured in steps of 5 nm from 380 up to and including 780 nm. From the results the X, Y, Z, x, y and L*, a* and b* coordinates were derived for a light source D65 and an observer of 10° (ISO 7724).

(18) Additionally diffusivity measurements were executed with calibration in “including specular component” modus, while the actual measurement were executed in the “excluding specular components” modus. By doing so the amount of diffuse reflected light compared to the total amount of reflected light is measured.

(19) Gloss was measured using a BYK-trigloss multiangle gloss measuring device. This device projects a light beam onto the sample's surface and measures the intensity of the specular reflected light. The angle can be chosen 20°, 60° or 85°. The intensity of the reflected light beam is expressed in gloss units.

(20) TABLE-US-00002 TABLE 1 Sample, acoustic panel L* Reflection, including specular 94.91 gloss, average Reflection, excluding specular 94.57 gloss, average

(21) TABLE-US-00003 TABLE 2 Sample, acoustic panel L*/L* incl gloss (%) Diffuse reflection, average 99.78

(22) TABLE-US-00004 TABLE 3 Sample, acoustic panel Gloss (gloss units) Measuring angle Average 20° 1.2 60° 1.7 85° 0.2

(23) Diffusivity is very high, and the very high diffusivity is confirmed by the results of the gloss measurements, which show extremely low values.

(24) With the high light reflection and low gloss the panels provide more light in a room equipped with the panels, and thereby the cost of lighting may be reduced, and further the living conditions are improved with a positive influence on the mood and productivity of people in the room.