METHOD OF RECYCLING FIBERGLASS AND/OR CARBON FIBERS FOR THERMAL INSULATION AND/OR SOUND INSULATION, USE OF

PARTICLES FOR THERMAL CAVITY WALL INSULATION,

AND A SOUND BARRIER PANEL

TECHNICAL FIELD

^" he present invention pertains generally to re-use ^; of fiberglass products, and in partic- ilar to a sound barrier pane! comprising reused fiberglass products,

BACKGROUND OF THE INVENTION

Iberglass and fiber-reinforced materials are generally used for a variety of eempa- lents and products such as wind turbine blades, ship hulls, building materials, piping, *G. This use of fiberglass is furthermore increasing rapidly. This- ever increasing tie- land for fiberglass products has also became problematic both in consumer and ornrnercial markets due to negative- environmental effects. The negative environ-- lental effects arise mainly from the fact that fiberglass is not biodegradable. This irh- ifies thai waste fiberglass often needs be disposed with at a landfill. Waste- fiberglass ■roducts are therefore also some of the most expensive waste material- to dispose. iberglass and other fiber-reinforced materials have long been difficult to recycle info sew and useful products. Some- manufacturers of fiberglass ^' goods are, for example, ^■ yiog to- dramatically increase the use. of reclaimed fiberglass in the. production pro- esses. Some manufacturers have done this by burning the. polymers and reclaiming e glass fibers for use in the- roduction- of new fiberglass products. These reclaimed :l,ass fibers are however severely weakened by the hea generated during the burning <f the polymers,, and can therefore only _, foe reused ^' in small amounts in some types of berglass products. Furthermore, this method of reusing the glass fibers is economically .unfavorable, for the manufacturer.. i WO 2011/116030 is disclosed a method of reusing waste wind turbine blades made ^• om fiberglass into new solid fiberglass products.

I US 7,913,812 is disclosed a sound barrier panel made from concrete, wherein one f the sides of the concrete panel is covered with a mix of concrete and fiberglass gra- u!ate, and in US 7,879,433- is disclosed an acoustical panel comprising layer of oarse particles. Despite prior attempts to reu e: was e fiberglass, there has been a long felt - and ever increasing - need for an alternative and eco- oraicaily more favorable wa of reducing the detrimental environmental effects related to waste fiberglass products.

One attempt to solve this problem is- disclosed-: in WO 00/70147, wherein: a method of manufacturing plates: tram reused fiberglass is disclosed. The fiberglass is shredded into a size of between 2-5 nd 76 mm, and then formed into, a plate, and a phenol resin is added:. Then the excess resin is removed and the plate Is dried, and cured in an oven. The plates have a density between 0.05 grams per cubic centimeters and 0,19 grams per cubic centimetres. The plates are relied into a desired thickness, which requires them to have a hard surface.

SU ARY OF THE INVENTION.

It is thus an object of th present invention to provide an; economically favorable method of reusing wast material comprising fiberglass and/or carbon fibers _. . if is a _. further object of the Invention to provide a sound barrier panel ..comprising mainly waste fiberglass.

According -to the present invention, the above-mentioned and other objects- are fulfilled by a first; aspect of the Invention pert.ain.ing to a; method of recycling fiberglass -and/or carbon fibers for thermal insulation and/or sound insulation, the method comprising the steps of

- providing waste materia!, at least in part formed by fiberglass- and/or c rbon fibers, and then

- shredding and/or granulating said waste material into particles having a certain average size, wherein said average particle size is between 2, mrn and -80- mm, preferably between 5 mrn and 60 mm, even more preferably between. 2 mhi and 35 mm, or 5 mrn and 2S mm, and then

- sieving the particles-, whereby inevitable dust-parfides and smaller debris formed during the shredding are- removed, and then

- forming the particles into -a coherent mat having a porous self supporting structure by binding the particles together using art adhesive. It Is understood that by the wording fiberglass is understood what is also known as so called glass reinforced plastic or glass fiber reinforced piastic. Essentially fiberglass is a fiber reinforced: polymer made of a plastic matrix, which is reinforced by fine fibers of glass. Fiberglass is a lightweight, extremely strong:, and robust material. Although strength properties are somewhat lower than in carbon fibers and. it is less stiff, the material is typically far less bottle, and the raw materials are muc less expensive. Its bulk strength and weight properties are also very favorable when compared to metals, and it can be easil formed using molding processes, the plastic matrix ma be a thermosetting piastic (most often epcsy, phenolics, polyester or vinyl ester) or thermoplastic.

Furthermore, it is understood that by the wording carbon fibers is understood what is also known as so called cgrbon-fi ^t-reinforced polymer or carhon-fiher-reinforced plastic. Carbon fiber is a very strong and light fiber-reinforced polymer which contains carbon fibers, The polymer is most .often epox , but other polymers, such as polyester, vinyl ester or nylon, are sometimes used. The composite ma also contain other fibers such as evlar, aluminium _* glass fibers as well a:s. carbon fiber.

Other terms used to refer to the material are graphite-reinforced polymer or graphite fiber-reinforced polymer (graphite fiber-reinforced polymer is less common since It clashes with giass-(fiber)Hreinforced polymer). In product advertisements it is sometimes referred to simply as graphite fiber, for short.

By shredding and/or granulating said waste material into particles having a certain average size., a form of the material is. achieved, which according to scientific investigations has excellent thermal and sound insulating properties. Furthermore, the waste material is transformed into a form where it is easily handled. For example it may be packed -compactly for transport to its place of intended! use or place of furthe processing before final use.

For shredding and/or granulating the waste material, a portable shredder and/or gran-qiator may be used, which a be transported to the place wherein the waste- material is disposed, whereby shredding granulation ca be carried out at the place of disposal -of said material and then transported: in shredded and/or granulated form to its place of use or place of further processing. By sieving the particles, whereby inevitable dust-particles and smaller Ceteris formed during the shredding are removed, it is achieved thai a more porous mat may be produced and with fees adhesive thai; otherwise would have to be used - without sieving.

Accordingly, by the invention a renewed use of a material, which otherwise would have to be disposed wit in a landfill :is achieved. As described more thoroughly in the detailed description, a mat is achieved-, which processes excellent sound dampening, and thermal insulating properties.

According to a preferred em&Odirnertf of the fi st aspect of the invention, the mat has a density of between 0,2 § per cubic cm and 0.8 g per cubic cm - more preferably between 0.2 g per cubic cm and 0.5-0.6 g per cubic cm. Investigations {see the detailed description for more information) have shown ^' , that particularly good sound dampening properties and thermal Insulation properties are achieved ^' if ^' mats having densities ^' in these ranges are achieved.

The waste material may in an .embodiment of the first, aspect of the invention be any of the following or parts of any of the following: wind turbine: blades or ship hulls or other construction parts.

The wast material may in an embodiment of the firs aspect of the invention foe divided into pieces, of a suitable siz before commencing the step of shredding and/or granulating said waste material. This is advantageous if the waste material is provided in piece -of a size which is too large for fitting into a shredder and/or granulator,

In an embodiment of the first aspeet of the Invention, the method further comprises the step of applying a flame and or fire refardani substance: lb the particles. Hereby the particles: can- foe used as parts of building material for buildings, wherein fire reguSativas require a certain level of flame and/or fir retardancy of the building materials used. in a embodiment of the first aspect of the invention, the method further comprises the step of treating the outer surface of the mat with a flame and/or fire reiardanl substance ^' . Hereby is achieved a mat that may .be used as a thermal insulation panel in houses and/or structures, where the fire regulative require usage of fireproof materials. According to ^' an embodiment of the first aspect of the invention, the fiarne and/or fire refardant substance may comprise a mix of the following constituents: ammonium phosphate, a source of citrate ion, and a source of enzoate ion. Hereby is achieved non-poisonous and non-hazardous fire and flame retardant particles of said waste material, which therefore -. also may be used as thermal insulation a.hd/ατ sound insulation in residential buildings. The flame refardant may for example be a;n embodiment of the flame refardant described in US 7,735s 549. _. Preferably, such particles treated with a flame and/or fire refardant may be used as thermal cavity wall Insulation. in an embodiment of the first aspect of the invention, the flame: and/or fire refardant substance comprises Sodium Silicate, investigations have shown thai Sodium Silicate is particularly good in reducing the flarwm ability of the mats according to the invention. For more details _* se for exampl the discussio of the fiammability tests reported in the detailed description.

The adhesive could for example be based on epoxy, phenolic formaldehyde resin or water soluble polymers.

In an embodiment of the first aspect of the Invention, the method further comprises the ^• Step of forming th coherent mat by mixing the particles wit an eiastomerie material, such a polyurethane. Thereby, a good sound and thermal insulating product is achieved, -which is much cheaper than using pure poiyurethane, which Is rather expensive. in another embodiment of the first aspect of th invention, the method: further comprises the step of forming said mat as an aggregate; of particles of the above mentioned kind and ^' particles of a second material in order To impart to the mat certain acoustical properties. These certain acoustical properties could for example be attenuation of -sound in certain frequency regions. Thus, the amount of and type of said second particles are preferably chosen in dependence of the kind- of noise which: needs to be attenuated by usage of said mat.

In a preferred embodiment of the first aspect of the invention, the method further comprises the step of forming the mat from a mixture of particles having different sizes. This mixture may also be chosen in order to impart to the mat certain acoustical prop- erties. These certain acoustical properties could for example be attenuation of sound in certain frequency regions.

In a preferred embodiment of the first aspect of the invention, th method further comprises the step of forming the mat by arranging the particles n a particular pattern according to sfce, This arrangement may also be chosen in order to Impart to the mat. certain acoustical properties.

In a preferred embodiment of the first aspec o the invention, the method further comprises: the ste of forming a composite panel, by arranging a plurality of mats in a particular pattern, wherein, eac mat is formed by particles of a particular size and/or material, wherein each mat is attached to a neighboring shee by an adhesive. Hereby is achieved a practical way of ma ufacturing larger panels -from smaller mats. in a preferred embodiment of the first aspect of th invention, the method. further comprises the step of forming the panel by several layers of said mats.

In a preferred embodiment of the first aspect of the invention, the method further comprises the st of equipping the mat(s) and/or composite panel with stiffening support elements, e.g. braces. By using stiffening support elements, a larger mat ca be produced and/or a mat having a looser structure can foe used, and/or a -mat, wherein less adhesive is used in binding the particles together.

In an embodiment of the f irst aspect of .the invention, the support elements are pliable or possess an Inherent resilience. Hereby is achieved a mat, whic can be bent in order to fit in/on a non-fiat mounting place. Furthermore, if such a mat is used in a road, e.g. a Highway sound harrier panel, then the resilience and/or pliability of the supporting elements reduces the risk of injury of a driver (or his/her passeng rs during a .collision ^' with said panel At the same time the resilience and/or pliability of the supporting elements reduces th risk of severe damage of the mat. in a preferred embodiment of the first aspect of: the invention, the method comprises she step of forming the stiffening support elements: as a frame around the periphery of the mat or composite panel..Hereby is achieved a mat, which is easy to handle without risking breaking pieces from the periphery of the mat during handling of it, e.g. during stacking -for transport and unloading after transport, as well as handling: during mount- ing of the mat in its intended use position. The frame will further allow a tight assembl of adjacent panels when installed for its intended purpose .

In an embodiment of the first aspect of the invention, the met od further comprises the step of attaching a substantially rigid plate to the frame on one of the two sides of the mat or composite panel. Alternatively, the rigid plate- ma be attached to the mat itself, e.g. by using an adhesive. In an embodiment of the first aspect of the invention, the plate covers substantially all of the side of the mat which is bounded by it. The plate is ih an embodiment of the first aspect of the invention perforated. This- perforation ^' reduces substantially the risk of back scattering of sound from the plate, whereby such an element (mat and plate) may for example be used inside buildings, wherein absorption -of sound generated wi hin said building may be of importance,, which for example is the case in ceilings.. Hence such an element may be used to cover otherwise bare ceilings and/or walls of a room in a building, e.g. a factory building, wherein back-scattering noise- from machines ma be a problem, or in offices, wherein reverberation of talking and/or babble noise may be a problem.

In an embodiment of the first aspect of the invention, the method, further comprises the step of attaching, a substantially rigid plate to the frame on each of the two sides of the mat or composite panel. Alternatively, a plate is attached to each- side of the mat or composite panel, thereby creating a cartridge, e.g. using an adhesive, in- ah embodiment of the first aspect of the invention, each of the plates covers substantially all of the side of the mat which is bounded by it. For the same reasons as mentioned above at least one of the plates may be- perforated. This embodiment may preferabl be used as a partition wall ^' in for exampl ah open office environment, and in such a case embodiments wherein both, plates are perforated may be advantageous. At least one of said plates may be perforated.

According to preferred embodiment of the first aspect of the invention, the support elements and/of the piate(s) are made from a material comprising any of the following; fiberglass, glass fiber reinforced plastic or polymer materials. Hereby is achieved a product, which may be eompieteiy recycled into another product of the same kind, if damaged, for exam le in. a car collision. The support elements and/or the piate(s ^' ) ma alternatively be made from a material comprising metal alloys or wood. In a preferred embodiment of the first aspect of ^" the- invention, the method ^' further ^■ corn- prises the ste of covering the mat or composite panel with a ^' water-impermeable membrane made from e.g. polymer. Hereby is. obtained a product which is especially adapted for outdoor use, for example as a sound barrier. Furthermore, the prevention of entrance of water into the structure of the mat precludes the detrimental effects It •would have on the acoustic and thermal insulating properties of said product hi an: embodiment of the first aspect of the invention, the method further comprises the ste of embedding the mat or composite panel into a fiberglass o glass: fiber reinforced plastic cartridge. Hereby is obtained an element, which is light in weight, compact, easy to handle and mount, and which also can be completely .recycled into a new mat according to the method -description above.

According to an embodiment, the invention also pertains to the use of a mat or composite pane I manufactured according to a method in accordance with ny of- the above mentioned .embodiments, as a. sound barrier, e.g. a traffic sound barrier.

According -to a further embodiment, the method further comprises the step of forming a traffic sound barrier panel, comprising at least two layers of mats and/or composite panels,: wherein- the mat and/o composite panels, of each layer have different densities. Traffic noise has primarily frequency components in the interval betwee : 500 Hz and 2000 Hz, and investigations performed by the Delta for the applicant, indicate that good sound dampening properties, in. the. frequency regio wherein traffic noise is most prominent, is achieved if two different densities are used of material is used Instead of one (These and other test results are reported in the detailed description of the present specification).

According to a further embodiment of the inventive method., the density of one of the layers is in the range from 0.2 g .per cubic cm to 0.4 g per cubic cm _i: and the density of another adjacent layer is. in the range from 0.4 g per cubic: cm to: 0,6 g per cubic cm. nvestigations have shown that a particularly good dampening of traffic noise is achieved with such a layered: structure, wherein the layers have densities in the above mentioned range.

Preferably, the at least two different densities are in the range from 0.2 g per cubic cm to 0.4 g per cubic cm and 0.8 g per cubic era to 0.8 g per cubic em. According to a further e bodiment, the mats in each layer have the same, thickness.

According to a further embodiment eac layer has thickness of between 4 crn and 1.0 cm, preferably between 4 cm and S em

According, to a yet further embodiment, the combined thickness: of the all the layers of the traffic sound barrier panel is between 8 cm and 30 cm, preferably between 8 em and 20 cm, even more preferably between 8 cm and 15 cm.

The above mentioned and furthe objects are achieved by a second aspect of the invention pertaining to the use of particles for thermal _. cavH wa.ll insulation, the particles being produced by a method comprising the steps of;

- providing waste material at least in part formed fay fiberglass and/or carbon fibers, and then

- shredding and/or granulating said waste material into particles having a certain average size., wherei said average particle size is between 2 mm and 35 mm, more preferably between 5 mm and 25 mm, and. then

- sieving the particles, whereby inevitable dust-particles and smaller debris formed during the shredding are removed.

As mentioned earlier the fairly good thermal insulation properties (The heat insulation is roughly 80% of that of mineral wool) of the material makes it suitable as being used in cavity wall insulation, whereby several environmental problems are solved simultaneously ~ excessive heating, is precluded and a material, which otherwise needed to be disposed with at a landfill, _. Is reused in an _. environmentally friendly manner

According to an embodiment of the second aspect, of the invention* the method further comprises the step of applying a flame and/or fire retardanf substance to the particles.

According to a further -embodiment sf the second aspect of the invention, said flame and/or fire re ardant substance comprises Sodium silicate. According to a further embodiment of the second aspect of the invention,, said flame and/or fire reiardarst substance comprises a mix of the following constituents: ammonium phosphate, a source of citrate ion, and a source ofbenzoat© ion.

The above mentioned and further objects are also achieved by third aspect of the invention pertaining to a sound barrier pane! comprising particles of shredded and/or granulated waste material at least in part formed by any of the - following constituents: fiberglass, glass fiber reinforced plastic and carbon fibers, the average size of said particles being between 2 mm and 80 mm, preferably between 5 mm and 60 mm, even more- preferably- etween: :2 mm and 35 mm, or S mm and 25 mm, the particles being bonded together by an adhesive into t least two coherent mats- having a self- supporting porous structure having a porous outer surface, wherein said sound barrier panel is build up of at least two layers of said mats, wher adjacent mats are fastened to each oilier using a fastener, and wherein the densities of the mat(s) in one layer Is different from the density of the mat(s) of the other layer(s).

According to a preferred embodiment of the third aspect of the invention, the mats have a density of between 0.2 g per eubio cm and: 0.8 g per cubic cm, or between 0,2 g per cubic cm and -0.5-0.6 g per cubic cm.

According to further embodiment ef the: third aspect of the invention; the density of one of the layers is in the range from 0.2 g per cubic cm to 0.4 g. per cubic meters, and the density of another adjacent layer is in the range from 0.4 g per cubic cm to 0.6 g per cubic meters.

According to further embodiment of the third aspect of the invention,, the at least two different densities are in the range from 0,2 g per cubic cm _. to 0.4 g per cubic cm and 0.6 g per cubic cm to 0.S g per cubic cm.

According to a further embodiment of the third aspect of the Invention, the mate in each layer have the same thickness.

According to a further embodiment of the third aspect of the. invention, each layer has a thickness of between 4 cm and 1.0 cm, preferably between 4 cm and 8 cm. According to a further -embodiment of th third aspect of the Invention, the combined thickness of the all the layers, of the sound, barrier, panel is between 8 cm and 30 cm, preferably between 8 cm and 20 cm, even more preferably between 8 cm and 15 -cm.

According to a further embodiment of the third aspect of the invention, the outer surface of said panel has been treated with a flame and/or fire reiardanf substance.

According to a further embodiment of the third aspect of the Invention, the flame and/or fire retardant substance comprises Sodium silicate.

^• According to a further embodimen of .the third aspect of the invention, the flame and/or fire retardant substance comprises a mix of the -following constituents; ammonium phosphate,- a source of citrate ion., and a source of benzoate ion. in a preferred embodiment of the third aspect of the invention, the- waste material -is any of the following or parts of any of the following : wind: turbine blades or ship hulls or other construction parte.

In an embodiment of the third aspect of the invention, the adhesive Is an elastorneric material, such as polyurethane,

In an embodiment, of the third aspect of the invention, said mat furthe comprises particles of a second -material in order to impart to the coherent porous mat certain acoustical properties.

In an embodiment -of the third aspect of the invention,, the mat{s) _: of each layer is formed from a mixture of particles having different sizes,.

In an -embodiment of the _. third aspect of the invention, the mat(s) in each, layer is formed by arranging the particles in a particular pattern according to- size- In an embodiment of the third aspect of the invention, _, the pattern Is formed by a particular arrangement of smaller sheets, each formed by said particles of a particular -si¾e and/or material, wherein each sheet is attached to a neighboring sheet by an adhesive. In an embodiment of the second aspect of the invention, the coherent porous mat is- formed by several layers of said sheets. According to a preferred embodiment of the third ^' aspect of the invention, the sound barrier panel further comprises stiffening support elements, e g. braces, for supporting the coherent porous mat. According to a preferred embodiment of the third aspect of the invention, the support elements are pliable or possess an inherent resilience.

According to a preferred embodiment of the third aspect of the invention, the stiffening support: elements ar formed as a frame around the peri hery of said sound barrier panel

•According to an embodiment of the third aspect of the invention, the sound barrier panel further comprises a substantially rigid plate, which is connected io the frame on one of the two sides of said sound barrier pane!. in an embodiment of the third aspect of the invention, th plate covers substantially all of the side of the sound barrier panei, _; which is bounded by if. Preferably, the plate is perforated.

According to an -alternative embodiment of the third aspect of the invention, the sound ^' barrier panel further comprises a substantially rigid ^" plate, which is connected to the frame on each of th two sides of said sound barrier panel., in an embodiment of the third aspect of the invention., each of the plates ^' covers- substantially all of the side Of the sound barrier panel, which is bounded by It Preferably, at least one of said plates is perforated.

According to a- preferred embodiment of the third aspect of the Invention, the support elements and/or the plaie(s) are made from a material comprising any of the following: fiberglass,, glass fiber reinforced plastic or polymer materials. Alternatively,- the support elements and/or th piate{s) are made from a material comprising a metal alloy or vVOOO,

According to a preferred embodiment of the third aspect of the. Invention., _, the sound barrier panel is covered with a .water-impermeable membrane, made f om: e.g. polymer ^• or a woven glass fiber dew. According to a preferred -embodiment of th third aspect of the invention, the sound barrier pane! is embedded in a cartridge embedding the panel in a cartridge being formed, by fiberglass or glass fiber reinforced plastic.

According to a preferred embodiment of the third aspect, of th invention, the sound barrier pane! is a traffic sound barrier panel.

According to a preferred embodiment of the third aspect of the invention, the sound barrier panel forms part of a traffic sound barrier.

The above mentioned and further objects are also achieved by a forth aspect of the invention pertaining to a traffic sound barrier which comprises a plurality of insulating panels in accordance with any of the above mentioned embodiments.

BREI.F - DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings, ^" in the following, preferred embodiments of the invention are explained in more detail with reference to. the drawings, wherein

Fig, 1 shows an embodiment of an insulating pane.!,

Fig, 2 shows an embodiment of an insulating panel,

Fig, 3 shows an embodiment of a insulating pane!,.

Fig, 4 shows an embodiment of an Insulating panel.

Fig. 5 shows an embodiment of an insulating panel,

Fig, 8 shows an embodiment of an insulating panel

Fig. 7 shows an embodiment of an insulating panel,

Rig, 8 shows an embodiment of an insulating panel,

Fig. 9 shows an embodiment of an insulating panel,

Fig. 10 shows an embodiment of an traffic sound barrier comprising a plurality of

insulating panels as described with reference ΐο any of the figures 1 - 9,

Fig 1 shows sound absorption curves for single mats of various densities, and

Fig. 12 shows sound absorption curves for combination of mats of various densities and fineness/coarseness in the particle, str ctu e:: DETAILED DESCRIPTION

The present invention will ne be described more fully hereinafter with reference to the accompanying drawings, in which exemplary- mbodiments of the invention are -shown. The invention may- however be embodied in different forms and should not be const ued as limited to he- embodiments set forth herein. Rather:, these embodiments are provided so that, this disclosure will be thorough, and complete, and fully convey the scope of the Invention to those .skilled in the art, Like referenc numerals refer to like elements throughout Like elements will, thus, not he described in detail with respect to the descri tion of each figure.

Fig. shows an embodiment of an insulating panel 2 comprising -particles of shredded and/or granulated waste, material at least i part formed by any of the following constituents: Fiberglass-, glass fiber reinforced plastic and carbon fibers. The particles are bonded together by an adhesive as a coherent mat.4 having a porous structure. The illustrated panel 2 has a rectangular shape., but Other shapes may be envisioned. In the illustrated insulating panel 2 the particles are bonded together as a self-supporting porous structure. The waste material from which the particles are formed may be wind turbine blades or ship hull® or other construction, parts, and the average size of the particles Is between 2 mm and 35 mm, preferably between 5 mm and 25 mm.

The coherent mat 4 or the particles itself may have been treated wit a flame and/or fire refardant substance. Said flame and/or fire refardant substance comprises a mix of the following constituents: Ammonium -phosphate., a- source of citrate ion, and a source of benzbate ion. The flame and/or fire refardant substance may ^' be an- embodiment of the- flame retard ant described in US 7,736,549.

The adhesive which is used to bond the particles together may be an elastorneric material,, such as polyurethane. The coherent porous mat. 4 may further comprise particles of a second material in order to impart to the coherent porous mat certain acoustical properties.

Fig, .2 shows -an. embodiment of an insulating panel 2, wherein the coherent porous .mat 4 Is formed from a mixture of particles having different sizes. The mat ^' comprises six different sheets 8 _: 8., 10, 12, 14-, 16 arranged in a- pattern. In the illustrated example th sheets 6, 8 and 14, 16 are formed f om particles of a size that is larger than the ^• particles, from., which t e sheets 10 and 12 are formed. Mem afive!y, Or in combination with this., the pattern may be formed by sheets 8, 8, 10, 12, 14, 16 comprising particles made frorrs different material _s wherein each sheet 8, 8, 10, 12, 14, 18 is attached to a neighboring sheet 6, 8, 10, 12, 14, 16 by an adhesive.

Fig. 3: shows an embodiment of an insulating panel 2, wherein the coherent porous mat 4 is also formed from a mixture of particles having different sizes. In the illustrated embodiment, the insulating panel 2 comprises a coherent porous mat 4. which is formed by several layers of sheets 18, 20, 22. In the illustrated example, the sheets 18 and 22 are thinner than the sheet 20. Furthermore, the sheet 20 is formed by particles having a large average size that the particles from which the sheets 18 and 22 is formed. In an embodiment the individual sheet 18, 20, 22 could also comprise par- tides made from a different material than at feast one of the sheets 18, 20, 22 in the same, mat 4,

Fig. 4 shows an alternative embodiment of an insulating panel 2, wherein the coherent porous mat 4 is also formed from a mixture of particles having different sizes. The illustrated mat 4 comprises a plurality of smaller sheets 24, 26, 28, 30, 2, 34, 3§, 38, 40 arranged/stacked in a plurality of layers (thre and two layers, respectively), each Stack of sheets -24, 26, 28, and 30, 32, 34, and 30, 40 being attached to a neighboring stack of sheets 24 _; , 28, 28, 30, 2, 34, 36, 38, 40 in order to form a complete mat 4.

Fig. 5 shows an alternative embodiment of an, insulating panel 2, wherei the coherent porou mat 4 further comprises stiffening support elements (braces) 42 and 44 for supporting the coherent porous mat 4. Preferably, the- support elements 42, 44 are pliable or posses an inherent resilience. Th illustrated mat could i an embodiment he a mat as described in accordance with any of the figures 1. - 4.

F¾. 6 shows an alternative embodiment of an insulating panel 2, wherein the stiffening support element are formed as a frame 46 around the periphery of the coherent porous mat -4. The mat 4 illustrated in Fig. 6 could in an; embodiment be a mat 4 ^' as. described In accordance with any of the figures 1 - 5..

Fig. 7 shows an alternative embodiment of an insulating panel 2, wherein the coherent porous mat 4 further comprises a substant lly rigid plate: 48, which is connected to the frame 46 on one of the .two sides of the coherent porous mat 4. In the illustrated era- odimeni the plate 48 covers substantially all of the: side of the coherent parous mat 4, which is bounded by it. The plate could for example be made from wood. The piste 48 comprises a plurality of perforations 50 in order to enhance the sound dampening effect .of the panel 2. M .a ^' preferred- embodiment of the illustrated panel % there could also he a similar plate attached to the other side of the mat 4. At leas one; hut preferably -both -of said plates are perforated as illustrated. Such an insulating, panel 2 could advantageously be used in partition walls in ope office environments, in which case the plates could be chosen to be decorative wood plates.

Alternatively, and especially if the insulating pane! 2 is for outdoor use, then herein the plate(s) may be made from a material comprising any of the following: .Fiberglass, glass fiber reinforced plastic- or polymer materials. The support, elements, described above may also be made from a materia! comprising any of the following-: Fiberglass, glass fiber reinforced plastic or polymer materials.

Fig. S shows an alternativ embodiment of an insulating panel 2-, wherein the coherent porous mat 4 is- covered with a front cover 52, made frorr? e.g. polymer or- fiberglass. Between the mat and the front cover 52 there is (optionally) placed a water imp rmeable membrane 54, This water imperfneablewernbrane 54 is preferably made from a. paiymer(s). The front cover 52 is- preferably replaceable-,, so that, it cart be replaced with a hew one in case of damage e.g. to vandalism such as graffiti paintings.

Fig. 9 shows -art .-embodiment of an insulating panel 2, wherein the mat 4 ^" is embedded In -.a cartridge 58, being formed by fiberglass or glas fiber reinforced plastic. An insulating panel 2 of this kind will be extremely weatherproof and could advantageously be used tn a traffic sound barrier e.g. along a. road, such as a highway. A further advantage of such- an insulating panel is. that, in case of unrepairable, damage for example due to a car collision, the damaged panel could be shredded and/or granulated as described above and reused for manufacturing new panels of the sam kind.

Fig. 10 show a traffic sound barrier 58 next to a road -80, wherein said traffic sound barrier 58 comprises a pluralit of Insulating panels 2 as described above in with reference to any of the figures i - 9. TEST RESULTS

-A ariety of tests ave been performed on samples of mats manufaciured according the invention. These tests, include, sound dampening properties, thermal _, insulation properties* mechanical -strength tests, water and moisture absorbanoe properties, and fismmabiljiy tests. These tests and the achieved results are described be! C , and whereve possible reference is made to known ISO standards for performing said tests.

Sound dampening properties

The sound dampening properties of the materia? is tested in a so called absorption lube with perpendicular sound incidence. The measurements were conducted in accordance with the standard DS/E ISO 10534-2, The dimension of the tube has the effect that only th frequency region between 50 Hz and 2000 Hz can be tested/ However, since traffic noise primarily, has frequency components in the: region between 50 Hz and 2000 Hz, the measurements would give a fairly -good indication of how good traffic noise is dampened.

The measurements were conducted with frequency resolution of 2 Hz in the frequency region 50 Hz - 2000 Hz, and the absorption coefficient determined . was recalculated info 1/3 octave levels. The test samples were, divided into 4 categories;

PL denoting samples made from fine particles, said samples having, a diameter of 90 mm and thickness of 50 mm and density of 0/19 g per cubic cm.

FT denoting samples made from fine particles, said samples having a diameter of 90 mm and thickness of 50 mm and density of 0.37 g per cubic cm.

GL denoting samples made from coarse particles, said, samples having a diameter of 90 mm and thickness of 50 mm and density of Q..1.Q g pe cubic cm.

GT denoting samples made from coarse particles, said samples having a diameter of 90 mm and thickness -of- 50 mm and densit of 0.40 g per cubic cm.

These -were compared to measurements made on Rockwool (M samples having a diameter of 90 mm and thickness of 50 mm. in table 1 below and Fig. 11 is shown the results for single samples, and in tabte 2 and Fig. 12 Is shown results for combinations of samples. The- calculations ^" of the acoustical dampening are- based on the standard for determining the dampening of traffic noise- (D8/E - 1793-1:1997).

Table 1; Showing calculated mean values: at center frequencies for 1/3 octaves from 50 Hz to 2000 Hz; and categorized n accordance with the standard DS/EN 1793:1997. FL+afr fcrFT 2xFT 2 0 ^' ·!· FL-s-FT PL* FT FL+air+FT

Hz air air * air

50 0,08 0.12 0.18 0.18 0.06 0.11 0.08

63 0.11 0.15 0.25 0.28 0.10 0: 16 0.13

80 0.14 0.21 0,37 0.33 0.12 0 22 0,15

100 0.22 0.31 0 51 0,49 0.18 0.31 0,21

128 0.29 0.42 0.64 0,66 0.20 0.43 0.27

160 0.44 0.57 0.74 0.80 0 27 0.83 0.37

200 0.61 0.71 0.79 0.87 0.41 0.77 0,53

250 0 76 0,79 0.77 0.84 0,55 0.88 0.70

315 0.85 0,80 0,72 0.78 0.74 0 92 0,87

400 0.88 0.78 0.69 0.09 0.90 0.80 0 97

500 0.83 0.74 o 0.69 0.97 0.88 0.98

630 0.76 0.72 0 74 0,70 0.98 0,88 0.97

800 0,70 0.75 0.80 0,82 0.97 0.93 0.98

1000 0.67 0 79 0.81 0.77 0.38 0.98 0.90 250 0.74 0,83 0.79 0.76 1 0,97 0.81

1600 0,89 0.84 0.85 0.84 0,95 0 95 0.81

2000 0.91 0.89 0.88 0.88 0.92 .0.95 0 97

DLaSp a 6 7 7 _. 7 10 11 9

Category A2 A2 m A2. A3 A3 A3

Table 2 Showing calculated mean values at _. the center frequencies for 1/3 octanes from 50 Hz to 2000 Hz, and categorized in accordance with the standard ^' DS EN 1793: 1997. Here ¾ i means a 50 mm. air gap.

According to the guidelines of ^' the Danish Road Directorate, traffic sound barriers mus have a dassifiestion of at least A3, From the above measurements- ¾ _{. ·} & seen that a pane! according to the invention: comprising mats having two different densities fulfills an A3 classification ~ thereby making them suitable traffic sound barriers.

Acoustical, tests In a: diffuse: sound field were also conducted and gives qualitatively similar results to those: referred to above, which indicates that the results obtained from the sound tu.be- measurements gives a valici indication of the sound dampening effect of the panels according to the invention. The heat conductivity of 8 samptes of mats according to the invention was conducted. The measurements have been conducted as a series of 8 single measurements with 5 minutes between each measurement using an iSOMET 2104 iambda-measurement equipment The samples and achieved results are listed in the table below:

As can be seen from these measurements, the heat- conductivity of the mats is roughly 20% higher than for mineral wool, which implies that same insulation properties can be achieved if; a roughly 20% thicker mat is used. The production of mineral wool is highly energy demanding, and in the long run it creates a waste disposal problem. Sinc the present invention actually solves a waste disposal, problem and provides a product almost as good as mineral wool, gives promising venues for the application of the mats according to the invention as insulation material.

Mechanical strength

The mechanical strength of the mats has been tested in accordance with the; standard testing methods DS E.N 826(1996) for -compressibility, and PS/EN 12089(1998} for feending. The results of these tests show that the mats have an average compression stress of between 95(8} kPa and 102(12} kPa at 10% deformation. The numbers in parenthesis is the standard deviation (n-l). The flexurai strength was deter ined to be on average: between 230(34) kPa and 284(35} kPa, Also here the numbers in parenthesis Is the standard deviation in-!)..

Water and moisture- fcserbarice Moisture sbsorbahce was measured by placing lest sampies in a container haying 100% relative humidity during- a period: of 100 days and periodically weighing- the .samples-.

Water absorbance was- tested b immersing test samples in water In a closed container during a period of 100 days and periodically weighing the samples.

Trie results shows a relativel low:- moisture and water absorbance and thai absorbed water arid moisture, relatively quickly drains from the samples. Furthermore, no mechanical disintegration of the samples was observed at the- termination of the period of exposure.

.Flamrnability

Samples of mats manufactured according to- the invention have also been investigated regarding to flammabiliiy in accordance with the principles: described In DIN 4102 "Brandverhalie.n von Baustoffen und Bauteileri', classification 2. The test sampies were categorized in the following- categories:- "Standard" - samples without any surface treatment.

"Burnbloek" - samples sprayed with Burnbloek -flame retardant.

"M gma" - sampies sprayed with .Mag a Firestop P flame retardant.

"Water glass" - samples sprayed with Sodium _. Silicate.

The tests- have shown that ail. samples tested show a rather low flammabiliiy. However, holes or other unevenness ruggedness;- in the surface structure of the samples- had a great influence on the flammabiliiy. in all five samples within each category were tested and the results are given in the table below:

The results show that surface treatment with Sodium Silicate is particularly efficient in reducing the fia msbili y of the mats according \a the invention.

L IST OF REFERENCE NUMBERS

In the fallowing ^' is given a list of reference nurnbets that are used in the delai ed description of the invention.

2 sound barrier panel

coherent porous mat,

6 40

42 _t 44 s up porting ele m ernts,

46 frame,

48 substantially rigid plate,

50 perforations In the substantially rigid plate

52 front cover.

54 water impermeable membrane,

56 fiberglass cartridge,

58 traffic sound barrier; and

60 road.