ACOUSTIC PRODUCTS

Abstract

The invention relates to a method of making an acoustic product and a novel acoustic product, wherein the acoustic product is made by adhering a facing to a first major surface of an acoustic insulation element by the use of an adhesive and curing the adhesive. The adhesive is an aqueous adhesive composition which comprises a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; a component (iii) in form of one or more plasticizers.

Claims

1. A method of making an acoustic product, the method comprising: providing an acoustic element comprising first and second major surfaces; providing a first facing; fixing the first facing to a first major surface of the acoustic element by the use of an adhesive; and curing the adhesive, wherein the adhesive is an aqueous adhesive composition which comprises a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; a component (iii) in form of one or more plasticizers.

2. The method according to claim 1, wherein the acoustic element is a man-made vitreous fibre (MMVF) panel.

3. The method according to claim 2, wherein the man-made vitreous fibre panel is formed of man-made vitreous fibres that are bonded by a cured binder wherein the binder before curing is a composition which comprises: a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; and a component (iii) in form of one or more plasticizers.

4. The method according to claim 1, wherein the first facing is a glass fibre veil.

5. The method according to claim 1, wherein the first facing has two major surfaces and the method comprises applying adhesive to a major surface of the first facing and then applying said major surface of the first facing to a first major surface of the acoustic element.

6. The method according to claim 5, comprising applying the adhesive by use of rollers.

7. The method according to claim 1, wherein the step of curing the adhesive is carried out at a temperature of from 100 to 300° C., preferably 170 to 270° C., preferably 180 to 250° C., preferably 190 to 230° C.

8. The method according to claim 1, wherein the acoustic element has a density in the range of 40 to 180 kg/m.sup.3, such as 80 to 160 kg/m.sup.3, preferably 100 to 140 kg/m.sup.3.

9. The method according to claim 1, wherein the loss on ignition (LOI) of the acoustic element is within the range of 2 to 8 wt %, preferably 3 to 5 wt %.

10. The method according to claim 1, comprising fixing a second facing to the second major surface of the acoustic element.

11. The method according to claim 10, comprising cutting the cured element in a plane substantially parallel to the major surfaces and smoothing each cut surface by abrasion to form two acoustic products.

12. The method according to claim 1, wherein the acoustic product has a thickness in the range of 12 to 100 mm, such as 15 to 50 mm.

13. The method according to claim 1, wherein the acoustic product has a width in the range of 550 to 650 mm, preferably around 600 mm.

14. The method according to claim 1, wherein the acoustic product has a length in the range of 550 to 650 mm or 1100 to 1300 mm, preferably around 600 mm, preferably around 1200 mm.

15. The method according to claim 1, comprising applying the adhesive in an amount of 5 to 12 g/m.sup.2 dry.

16. The method according to claim 1, wherein the acoustic product is a ceiling panel.

17. The method according to claim 1, wherein the acoustic product is a wall panel.

18. The method according to claim 1, wherein the acoustic product is a baffle.

19. An acoustic product obtained by the method according to claim 1.

20. An acoustic product comprising an acoustic element comprising first and second major surfaces and a first facing, wherein the first facing is fixed to the first major surface of the acoustic element by an adhesive, wherein the adhesive before curing is an adhesive composition comprising: a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; a component (iii) in form of one or more plasticizers.

21. A suspended ceiling system comprising a plurality of acoustic products according to claim 19 suspended in a grid.

22. A wall system comprising a plurality of acoustic products according to claim 19 suspended on a wall.

23. The method according to claim 1, wherein component (i) is in form of one or more ammonia-oxidized lignins (AOL's).

24. The method to claim 1, wherein the component (ii) comprises one or more cross-linkers selected from β-hydroxyalkylamide-cross-linkers and/or oxazoline-cross-linkers.

25. The method according to claim 1, wherein the component (ii) comprises one or more cross-linkers selected from the group consisting of polyethylene imine, polyvinyl amine, fatty amines; and/or one more cross-linkers in form of fatty amides; and/or one or more cross-linkers selected from the group consisting of dimethoxyethanal, glycolaldehyde, glyoxalic acid; and/or one or more cross-linkers selected from polyester polyols, such as polycaprolactone; and/or one or more cross-linkers selected from the group consisting of starch, modified starch, CMC; and/or one or more cross-linkers in form of aliphatic multifunctional carbodiimides; and/or one or more cross-linkers selected from melamine based cross-linkers, such as a hexakis(methylmethoxy)melamine (HMMM) based cross-linkers.

26. The method according to claim 1, wherein the aqueous adhesive composition comprises component (ii) in an amount of 1 to 40 wt.-%, such as 4 to 20 wt.-%, such as 6 to 12 wt.-%, based on the dry weight of component (i).

27. The method according to claim 1, wherein component (iii) comprises one or more plasticizers selected from the group consisting of polyethylene glycols, polyethylene glycol ethers, polyethers, hydrogenated sugars, phthalates and/or acids, such as adipic acid, vanillic acid, lactic acid and/or ferullic acid, acrylic polymers, polyvinyl alcohol, polyurethane dispersions, ethylene carbonate, propylene carbonate, lactones, lactams, lactides, acrylic based polymers with free carboxy groups and/or polyurethane dispersions with free carboxy groups.

28. The method according to claim 1, wherein component (iii) comprises one or more plasticizers selected from the group consisting of fatty alcohols, monohydroxy alcohols, such as pentanol, stearyl alcohol; and/or one or more plasticizers selected from the group consisting of alkoxylates such as ethoxylates, such as butanol ethoxylates, such as butoxytriglycol; and/or one or more plasticizers in form of propylene glycols; and/or one or more plasticizers in form of glycol esters; and/or one or more plasticizers selected from the group consisting of adipates, acetates, benzoates, cyclobenzoates, citrates, stearates, sorbates, sebacates, azelates, butyrates, valerates; and/or one or more plasticizers selected from the group consisting of phenol derivatives, such as alkyl or aryl substituted phenols; and/or one or more plasticizers selected from the group consisting of silanols, siloxanes; and/or one or more plasticizers selected from the group consisting of sulfates such as alkyl sulfates, sulfonates such as alkyl aryl sulfonates such as alkyl and/or sulfonates, phosphates such as tripolyphosphates; and/or one or more plasticizers in form of hydroxy acids; and/or one or more plasticizers selected from the group consisting of monomeric amides, such as acetamides, benzamide, fatty acid amides such as tall oil amides; and/or one or more plasticizers selected from the group consisting of quaternary ammonium compounds such as trimethylglycine, distearyldimethylammoniumchloride; and/or one or more plasticizers selected from the group consisting of vegetable oils such as castor oil, palm oil, linseed oil, tall oil, soybean oil; and/or one or more plasticizers selected from the group consisting of hydrogenated oils, acetylated oils; and/or one or more plasticizers selected from acid methyl esters; and/or one or more plasticizers selected from the group consisting of alkyl polyglucosides, gluconamides, aminoglucoseamides, sucrose esters, sorbitan esters; and/or one or more plasticizers selected from the group consisting of polyethylene glycols, polyethylene glycol ethers.

29. The method according to claim 1, wherein component (iii) is present in the aqueous adhesive composition in an amount of 0.5 to 50, preferably 2.5 to 25, more preferably 3 to 15 wt.-%, based on the dry weight of component (i).

30. The method according to claim 1, wherein the aqueous adhesive composition comprises a further component (iv) in form of one or more coupling agents, such as organofunctional silanes.

31. The method according to claim 1, wherein the aqueous adhesive composition further comprises a component (v) in form of one or more components selected from the group of ammonia, amines or any salts thereof.

32. The method according to claim 1, wherein the aqueous adhesive composition comprises a further component in form of urea, in particular in an amount 5 to 40 wt.-%, such as 10 to 30 wt.-%, such as 15 to 25 wt.-%, based on the dry weight of component (i).

33. The method according to claim 1, wherein the aqueous adhesive composition consists essentially of a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; a component (iii) in form of one or more plasticizers; a component (iv) in form of one or more coupling agents, such as organofunctional silanes; optionally a component in form of one or more compounds selected from the group of ammonia, amines or any salts thereof; optionally a component in form of urea; optionally a component in form of a more reactive or non-reactive silicones; optionally a hydrocarbon oil; optionally one or more surface active agents; water.

Description

FIGURES

[0537] FIG. 1 shows a section from a possible lignin structure.

[0538] FIG. 2 shows examples of lignin precursors and common inter-unit linkages.

[0539] FIG. 3 shows the at least four groups of technical lignins available in the market.

[0540] FIG. 4 shows a summary of the properties of some technical lignins.

[0541] FIG. 5 is a perspective view of an acoustic product according to the invention;

[0542] FIG. 6 is a diagrammatic illustration of a method of the invention up to the curing oven stage;

[0543] FIG. 7 is a diagrammatic continuation of FIG. 6 beyond the curing oven.

[0544] The acoustic product 1 of FIG. 5 has a smooth, flat, sound-absorbing front face 2 extending in what is referred to as the XY plane, a back face 3 and side edges 4 extending in the Z direction between the front and rear faces. The acoustic product consists of an acoustic element which is a bonded MMVF matrix, together with a facing on the front face 2 and also on the rear face 3. The side edges 4 may be square or may have some other profile.

[0545] As shown in FIG. 6, a typical apparatus for making the product comprises a cascade spinner 6 having a plurality of rotors 7 mounted on the front face positioned to receive melt from a melt gutter 8 whereby melt which falls on to the rotors is thrown from one rotor to the next and from the rotors as fibres. These fibres are entrained in air from in and around the rotors 7 whereby the fibres are carried forward into a collecting chamber 9 having a perforated collector conveyor 10 in its base. Air is sucked through the collector and a web 11 forms on the collector and is carried out of the collecting chamber 9 and on to another conveyor 12. The primary web 11 is led by conveyor 12 into the top of a cross-lapping pendulum 13 by which layers of the primary web are cross-lapped on one another as they are collected as a secondary web 15A beneath the pendulum on conveyor 14.

[0546] The secondary web 15A is led by conveyor 14 to a pair of conveyors 16 for applying vertical compression to the secondary web from its natural depth, at point A, to its compressed depth at point B. The secondary web at point A has a weight per unit area of W.

[0547] The compressed secondary web 15B is transferred from point C to point D by conveyors 17. Conveyors 16 and 17 usually all travel at substantially the same speed so as to establish a constant speed of travel of the secondary web from the vertical compression stage AB to point D.

[0548] The web is then transported between a pair of conveyors 18 which extend between points E and F. Conveyors 18 travel much more slowly than conveyors 16 and 17 so that longitudinal compression is applied between points D and F.

[0549] Although items 14, 16, 17 and 18 are shown for clarity as conveyor belts spaced apart from one another in the X direction, in practice they are normally very close to one another in the X direction.

[0550] Points D and E are preferably sufficiently close to one another or are interconnected by bands, to prevent the secondary web escaping from the desired line of travel. As a result, substantial longitudinal compression has occurred when the web emerges at point F. Restraining guides can be provided, if necessary, between D and E to prevent break out of the web if D and E are not close together.

[0551] The resultant longitudinally compressed batt 15C is then carried along conveyor 19 between points G and H at a higher speed than by the conveyors 18. This applies some longitudinal decompression or extension to the longitudinally compressed web and prevents the web breaking out from the desired line of travel and, for instance, buckling upwards due to internal forces within the web. If desired or necessary, a conveyor or other guide (not shown) may rest on the upper surface of the batt (above conveyor 19) so as to ensure that there is no breakout.

[0552] When vertical compression is to be applied to the longitudinally compressed web, this is done by passing the web, after it leaves point H, between conveyors 20, which converge so as to compress the web vertically as it travels between the conveyors and points I and J.

[0553] The resultant uncured batt 15D has first and second major faces 3A and 3B. A glass fibre veil 22 from rolls 23 is then contacted with faces 3A and 3B. The glass veil 22 has been provided with adhesive as required by the invention, to bond the veil to the batt. The resultant assembly then passes through a curing oven 25 where just sufficient pressure is applied by conveyors 24 to hold the sandwich of two layers of veil 22 and the batt 15D together while curing of the binder for the MMVF and the adhesive occurs.

[0554] The bonded batt 15E emerges from the curing oven and is sliced centrally by a band saw 26 or other suitable saw into two cut batts 27 each having an outer face 3 carrying the veil 22 and an inner cut face 2. Each cut batt 27 is supported on a conveyor 28 and travels beneath an abrading belt 29 where it is abraded or ground to a flat configuration, and a further facing 22 is applied from roll 30 and bonded to the abraded surface 2. The abraded or ground cut batt 27 is then divided by appropriate cutters 31 into individual batts 1 which are carried away on conveyor 32.

[0555] Paint may be applied to either or both faces.

[0556] Throughout this description, conveyor bands or belts are illustrated but any or all of the conveyors can be replaced by any suitable means of causing the relevant transport with acceleration, deceleration or vertical compression as required. For instance roller trains may be used instead of belts.

EXAMPLES

[0557] Testing was undertaken to determine the peel strength of a glass veil that had been applied to an MMVF acoustic element using an adhesive as required by claim 1. The acoustic element had the properties defined in Table 1 below:

TABLE-US-00011 TABLE 1 Density of batt of Loss on ignition MMVF in a matrix of the batt of comprising binder MMVF bonded by Binder kg/m.sup.3 the binder % composition Glass veil 145 3.8 See details I50 U (Owens below Corning). Base weight 50 g/m2, binder content 18% (modified urea formaldehyde resin)

[0558] Determination of LOI (binder content) is performed according to DS/EN13820:2003 Determination of organic content, where the binder content is defined as the quantity of organic material burnt away at a given temperature, here using (590±20° C.) for at least 10 min or more until constant mass. Determination of ignition loss consists of at least 10 g wool corresponding to 8-20 cut-outs (minimum 8 cut-outs) performed evenly distributed over the test specimen using a cork borer ensuring to comprise an entire product thickness.

[0559] Peel strength is determined as follows:

[0560] Veil adhesion measurement is made using a 5 cm wide metal punch and a small manual weight with a hook [g].

[0561] Measuring Method:

[0562] Place the product on an even flat surface,

[0563] Using a cutter, cut the surface of the veil for a length of approx. 50 cm,

[0564] Attach the torn end to the grip of a dynamometer and pull.

[0565] At the same time the maximum and minimum scale deflection should be read.

[0566] Results

TABLE-US-00012 Length direction (g) Cross direction (g) Board 1 A 151 B 141 C 145 D 103 Board 2 A 252 B 116 C 101 D 134 Average 159 127

[0567] It is generally considered that a peel strength at least 100 g is necessary for commercial production. It can be seen that the products of the invention comfortably meet that standard.

[0568] Details of Binder Composition:

[0569] 3267 kg of water is charged in 6000 l reactor followed by 287 kg of ammonia water (24.7%). Then 1531 kg of Lignin UPM BioPiva 100 is slowly added over a period of 30 min to 45 min. The mixture is heated to 40° C. and kept at that temperature for 1 hour. After 1 hour a check is made on insolubilized lignin. This can be made by checking the solution on a glass plate or a Hegman gauge. Insolubilized lignin is seen as small particles in the brown binder. During the dissolution step the lignin solution will change color from brown to shiny black.

[0570] After the lignin is completely dissolved, 1 liter of a foam dampening agent (Skumdmper 11-10 from NCA-Verodan) is added. Temperature of the batch is maintained at 40° C.

[0571] Then addition of 307.5 kg 35% hydrogen peroxide is started. The hydrogen peroxide is dosed at a rate of 200-300 liter/hour. First half of the hydrogen peroxide is added at a rate of 200 l/h where after the dosage rate is increased to 300 liter/hour.

[0572] During the addition of hydrogen peroxide the temperature in the reaction mixture is controlled by heating or cooling in such a way that a final reaction temperature of 65° C. is reached.

[0573] After 15 min reaction at 65° C. the reaction mixture is cooled to a temperature below 50° C. Hereby a resin is obtained having a COOH value of 1.2 mmol/g solids.

[0574] From this ammonia oxidized lignin (AOL) resin, a binder was formulated by addition of 270 kg polyethylene glycol 200 and 281 kg of a 31% solution of a 3-hydroxyalkylamide (Primid XL-552) in water.