WO2012091557A1

WO2012091557A1 - Composite materials and shaped articles

Info

Publication number: WO2012091557A1
Application number: PCT/NL2011/050855
Authority: WO
Inventors: Pieter Jan DWARSHUIS; Ronald Edward VAN RIEMSDIJK
Original assignee: Holland Composites Innovation B.V.
Priority date: 2010-12-31
Filing date: 2011-12-16
Publication date: 2012-07-05
Also published as: NL2005946C2

Abstract

The present invention relates to a process for the preparation of a composite material from a particulate binder material having an average particle size (D90) of from 15 to 850 µm and a particulate polyisocyanurate and/or polyurethane foam having a closed cell content of at or above 90%, as determined according to ASTM D 2856,Procedure A, comprising the steps of: a) blending the particulate binder material and the particulate foam material, preferably in a volume ratio of 60:40 to 10:90, and b) subjecting the blended material obtained in a) to a curing step under increased temperature and pressure to obtain a composite material. The invention further relates to the composite material thus obtained, and to its use as building materials or as panelling.

Description

Composite Materials and Shaped Articles

The present invention relates to composite materials prepared from particulate binder materials and from particulate filler rigid polyurethane material. The present invention further relates to a method for the preparation of the composites and shaped articles therefrom, and to their use as building materials, for furniture and for other structural and decorative applications. Background of the invention

Composite materials, in particular shaped articles such as panels are used in various applications, for instance as outer claddings for buildings, as visual displays in advertising activities, and in structural applications. Such materials usually comprise a binder material and a solid filler material, typically a woven and/or non-woven fibre material that offers structural integrity and/or insulation value, as well as external layers facing the environment.

Specifically for outdoor applications, the composites have to be durably resistant to the different weathering conditions, including variations in humidity and temperature, exposure to UV and other radiation, and exposure to chemicals (micro)biological growth.

Composite materials for outdoor use have been developed based on fibre-enforced concrete material. However, these materials are difficult to shape or affix due to the low mechanical strength of the composites.

Furthermore, the materials have a high density, which in combination with the low mechanical strength requires comparatively thick panels, which in turn makes them difficult to attach them for instance exterior building surfaces, limiting their use to applications and constructions that can bear the high weight. A further issue with these materials is the leaching of highly corrosive salts.

In order to reduce weight and/or to improve mechanical performance, composites based on plywood sheet materials and/or wood chips have been developed. Plywood usually consists of sheets of wood that are glued or cemented together, using for instance thermosetting polyurethane or thermosetting unsaturated polyester and styrene binders, or epoxy resin and amino curing agent binders. To reduce the cost of composites, recycled materials are often used as at least part of the filler material. US-A-6,044,604 for instance discloses a composite roofing board having a paper layer made of recycled paper fibers. US-A-5, 718,096 discloses using recycled materials and glass fibers in composite panel elements for use in building structures. US-A-6,322,731 discloses the use of rice husks, wheat husks and sawdust in forming constructions panels.

However, while these materials show better mechanical properties as compared to fibre enforced concrete, they tend to emit organic compounds such as for example formaldehyde. For environmental reasons, there is a trend to use materials that emit low levels of organic volatiles.

Further, the process requires the handling of liquid binder materials that may emit volatile components even after the curing stage, while exposing the applier to toxic or irritant chemicals.

EP0528456 discloses composite materials for car interiors prepared from car interior polyurethane parts such as seats, head and arm rests, and a particulate binder comprising epoxy resins in combination with polyesters. Typically, such foams are not comprising an amount of at or more than 90% of closed cells. Furthermore, the thus obtained composite materials are only described as suitable as sound proofing material, but not structurally stable.

WO-A-2008/020768 discloses a process for manufacturing a composite board material from wood fibre does not, or only to a limited scale involve handling of toxic or irritant liquid materials. The process includes mixing together from 15% to 30% of waste powder coating powder, typically a polyester thermosetting resin, with sawdust having a particle size typically below 3 mm, there being from 40% to 75% of sawdust in the mix, and from 0.1 % to 30% of a water based acrylic paint. Furthermore, the composite materials disclosed in WO-A-2008/020768 are inherently highly flammable, and hence not suitable as building materials without further modification, such as addition of fire retardants. Furthermore, the use of liquid paint alongside powdered particles will result in a cumbersome handling, and coalescing particles with inhomogeneous distribution of acrylic polymer, as well as causing issues due to encapsulated water that will gasify during the curing stage, leading to composite defects. Moreover, wood fibre, sawdust and/or acrylic paints will release volatile organic compounds, which will reduce the applicability of the obtained composite materials to areas where fogging out is not considered an issue. Yet a further disadvantage is the low hydrolytic stability of such composite products, since saw dust and woodchips are particularly vulnerable to moisture, potentially resulting in wood deterioration and rot.

In view of the foregoing, it should be apparent that there exists a need for a low-cost and highly stable composite building material that can be formed into building structural panels using a relatively simple and

inexpensive manufacturing process, such that the panels have adequate dimensional stability, durability and flexibility.

Applicants have now surprisingly found that composite materials can be prepared from a particulate binder material and a fibrous material that is inherently fire retardant and resistant to humidity and/or rot. Furthermore, the materials can advantageously be sourced from recycling materials that otherwise has little other uses than fuel purposes.

Accordingly, the present invention relates to a process for the preparation of a composite material from a particulate binder material having an average particle size (D90) of from 15 to 850 pm and a particulate polyisocyanurate or polyurethane foam having a closed cell content of at or above 90%, as determined according to ASTM D 2856, Procedure A, comprising the steps of: a) blending the particulate binder material and the particulate foam material, preferably in a volume ratio of 60:40 to 10:90 , and b) subjecting the blended material obtained in a) to a curing step under increased temperature and pressure to obtain a composite material.

The present invention further provides a composite material that comprises primarily a particulate polyisocyanurate or polyurethane foam

(further referred to as polyurethane or PU) waste material and a particulate binder material obtainable by the process. More particularly, the composite material preferably comprises waste powder or dust polyurethane material and waste powder coating binder, optionally with additives and fillers. The recycled ground rigid polyurethane foam particles were found to increase the insulation properties, while not affecting fire retardancy negatively. It is still another object of the present invention to provide a composite material that includes various amounts of other natural or synthetic recycled or virgin substances in proportions that will contribute to the structural integrity or other features of the material.

Accordingly, there remains a need for composite materials that inherently have a higher fire retardancy and a higher resistance to water and/or deterioration.

The particulate binder material may be a thermoset or a thermoplastic binder material. The use of such materials allows to avoid toxic or

environmentally harmful emissions of volatile compounds, as well as reduced exposure for the applicator to small molecules. Preferably, the particulate binder material comprises waste powder coating material obtained from overspray and/or powder coating production. Preferably, the binder is a thermoset binder; more preferably the binder comprises waste powder coating material.

While both thermoset or thermoplastic binders may be employed, preferably, the particulate binder material comprises a thermoset polymeric material due to the higher strength obtainable by these components.

Suitable particulate thermoplastic materials according to the present invention may advantageously comprise one or more functionalized

polyolefins chosen among functionalized polyethylenes, functionalized polypropylenes, ethylene acid copolymers, ionomers, functionalized ethylene vinyl acetate (EVA) copolymers, functionalized ethylene alkyl (meth)acrylate copolymers, polyethylene terephthalate (PET), poly-ethylene-furanoate (PEF) and mixtures thereof. Preferably, the thermoplastic material comprises polypropylene, further preferably comprising one or more functionalized polyolefins, preferably ethylene copolymers and/or ionomers for improved adhesion. The thermoplastic binder polymer preferably has a melt flow index less than 500 g/10 min according to ASTM Method No. D1238 at 190°C and a load of 2160 g. However, particularly suitable thermoplastic binders are recycled thermoplastics as disclosed in US-A-6191228, however in particulate form suitable for the present process, including HDPE and PET or PEF, polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and mixtures thereof. Suitable particulate thermoset binder materials according to the present invention are typically used for powder coating processes. The process for production of powder coatings compositions is well-known in the art and need not be described herein. Reference is e.g. made to the following books:

Powder Coatings, T.A. Misev, Wiley, 1991 (particularly Chapter 5); Surface Coatings, S. Paul, Wiley, 1985 (particularly Chapter 8.4); Surface Coatings, vol. 2, OCCA, TAFE Educational Books, 1984 (particularly Chapter 42); and The Science of Powder Coatings, D.A. Bate, SITA Technology, London.

Most thermoset powders have a molecular weight lower than that of thermoplastic materials, yet higher than that of liquid coatings. Thermoset materials are typically solid resinous materials that, when heated, melt, flow, and - unlike thermoplastics - will then, or at the same time crosslink with one another, or other reactive substances present in the particles, so-called curing agents, to form compounds with higher molecular weights. The crosslinking reaction is usually known as curing step. After curing, a thermoset coating remains thermally stable, meaning it cannot be melted back into a liquid from further heating due to the high average molecular weights of the crosslinked polymers, and the three-dimensional network formed that usually results in gel formation.

In order to prepare such particulate thermoset powders, one or more thermoset resins are intimately mixed with suitable curing or crosslinking agents, to form a so-called master batch. The thus obtained reactive blends are cooled down immediately, and subsequently conveniently shaped into a very fine powder that can be applied as a thin powdery film on substrates to be coated. Alternatively, the resin and curing agents, optionally together with additives such as pigments, flow enhancers, UV stabilizers, catalysts and fillers are added and blended in suitable extruders prior to the shaping step. The shaping step usually involves milling. Suitable mills include ball mills.

The most commonly applied thermoset powder coating materials are derived from resins having epoxy, hydroxyl or carboxyl, acrylic, urethane and/or silicone functionality. These generally require lower curing

temperatures than thermoplastics, and curing conditions are often tailored by additives to accelerate or delay the curing reaction. The powder coating material is usually applied through electrostatic deposition. The powder-coated product are then thoroughly heated to a first temperature to allow the thermosetting resin to flow evenly over the targeted surface because once crosslinking is completed, the resin binder material cannot be returned into a liquid state to correct any flaws in the coating under normal conditions. Subsequently, the temperature is increased until the curing temperature is a reached. Accordingly, for successful coating and/or

compounding results, it is necessary to employ an appropriate formulation with well-defined curing cycle, particularly with respect to melting and curing temperatures.

One of the most significant developments in thermoset powder coating involves the capacity to engineer resin types with variable properties designed to complement metal finishing treatments. This broader range of

characteristics has led to an increase in specialized roles for thermoset powders, with polyesters and acrylics finding greater use in the automotive and appliance industries despite the traditional reliance on epoxy-based coatings. Most thermoset powders can provide a high level of corrosion, temperature, and impact resistance. They can also be designed with a wide range of colours, glosses, and surface finishes. Coating texture can be wrinkled, smooth, or matte, while film thickness is highly adjustable. Powder coatings can be effectively applied through electrostatic spraying

Epoxy resin based thermoset resins are widely used in industrial powder coating, and they offer a wide range of formulation options. Different types of epoxy resins can be fabricated into functional thick film or more decorative thin film, while their crosslinking properties are similar to those of epoxy adhesives and paints. Most epoxy-based materials are crafted to be thermally stable at room temperature.

Epoxy resins are usually produced from bisphenol A and

epichlorohydrin. Epoxy resin grades employed as powder coating resins typically have an epoxy content of about 1350 mmol/kg, a molecular weight of about 1500 and a viscosity of about 3.5 Pa.s at 150 °C and 0.7 Pa.s at 175 °C. Typical curing (cross-linking) agents include polyamines.

A different thermoset powder advantageously employs epoxy resins but cured with or polycarboxylated polyester resins. A typical coating resin would for instance comprise 70 wt% of the above epoxy resin, and 30 wt% of a saturated carboxylated polyester resin having an acid number of about 77 and a viscosity of about 1 .3 Pa.s at 165°C. An epoxy resin cross-linked with a reactive acid polyester will form a blend, or hybrid, material that has flexibility and impact resistance qualities similar to those of other epoxies, but provides a higher level of ultraviolet light protection. These blends are effective when applied as an electrostatic spray and have a range of applications similar to those of thin film epoxies.

A further family of resins used for powder coating applications beneficial for their high level of exterior durability and relative ease of application are acrylic powder coatings. Acrylic resins require curing temperatures close to those of hydroxyl polyesters, and they combine high quality surface aesthetics with flexibility and impact resistance. They also exhibit excellent alkali resistance, making them well-suited for use on appliances, such as ovens and washing machines. Acrylic powder coatings can be effectively applied through electrostatic spraying and have adjustable thin film characteristics. However, acrylics are more responsive to substrate attributes than most other powder coatings, making them incompatible with certain chemical compounds. Aside from their use in appliances, acrylic powder coatings are often employed for aluminum extrusions, automotive trim components, and tractors.

Urethane powders provide both a high quality surface finish and resistance to wear. It is usually fabricated as thin film because its thick film form exhibits lower impact resistance and flexibility. A urethane coating has aesthetic qualities comparable to those of liquid paint, and it is commonly used for coating light fixtures, furniture, automotive components, wheels, and appliances.

Carboxyl polyesters have durability characteristics similar to those of epoxy-polyester blends and weathering resistance comparable to urethane. They have consistent mechanical properties across a range of standard coating thicknesses and provide a high level of flow, glossiness, and material strength. However, their resistance to chemical solvents can be lower than that of hydroxyl coatings. Carboxyl polyester powder coating is commonly used on irrigation pipes, outdoor furniture, fences, aluminium extrusions, and steel wheels. Preferably, the subject process employs as waste powder coating compositions (hereinafter waste powders or waste powder coatings) as particulate thermoset resin binder.

Such waste powders are usually obtained during the preparation or application of powder coating compositions. Waste powders may be obtained at various stages in the preparation or application process.

An important source of waste powder is also found during preparation of the powder: the fines left after the milling and separation step, usually by cyclone extraction, cannot be used as powder coating since they, among factors, tend to block the spraying lines, which can only operate successfully with powders of a narrow particle size distribution. Suitable thermoset powder coating materials for electrostatic application usually have an average particle size (D90) of from 15 to 250 pm. Coatings of high quality of appearance are usually formed from even narrower particle size distribution, and more preferably at the lower end of the above range. Examples of an average particle size (D90) as narrow as from 15 to 50 pm are found in this area.

However, coagulation and partial gelling of the particles during the process will render them unsuitable for the initial purpose.

A further source of waste powder coatings are powders resulting from overspray during application that may no longer be suitable, for instance by inclusion of dust or formation of fines due to abrasion, or coagulates; or colour change on application lines that apply multiple colours in succession.

Waste powders thus obtained usually are contaminated, and will not have the narrow particle size distribution required for the electrostatic application process. The direct recycling of waste powder is possible only subject to stringent conditions and limited to second-rate uses, such as primer coatings in two-layer systems or as coatings in applications with a lower demand on coating appearance, such as for instance scaffoldings or structures that are usually hidden from the eye of the beholder.

Although a number of processes have been devised to reprocess and recycle waste powder as feed material in the production of powder coatings, such as for instance disclosed in DE-A-4028567, these only usually allow a limited amount of the recycled powder material to be employed, since they usually involve re-extrusion and/or re-milling of collected waste powder. The thus obtained reprocessed powders are however limited in the amount of recycled powder on virgin powder, and largely dependent on the powder composition and reactivity, which may be negatively affected by crosslinking during the extrusion and/or milling steps, resulting in application and flow problems due to larger particles and gelling. Accordingly, the disclosed process does not suffice for the recycling of the whole amount of waste powder generated. Further, powders prepared partly with recycled waste tend to give more defects in the final coatings. Accordingly, it would be highly beneficial to recycle waste powder to the process according to the present invention.

Suitable particulate polyurethane foam materials are those typically obtained from cutting or milling or otherwise shaping rigid polyurethane foams. These are preferably obtained by A) contacting an isocyanate and an active hydrogen containing compound, such as a polyol in the presence of a catalyst, a foam stabilizer and a blowing agent to obtaing a foam, and

B) cutting or milling the foam to obtain shaped foam articles and the

particulate foam material as cutting or milling waste.

The organic polyisocyanate compounds are usually of the R(NCO)_n type, wherein n > 2 and R represents an aliphatic or aromatic group.

Preferably, use is made of diisocyanates or polyisocyanates, having an average of 2 to 4 isocyanate groups per molecule. A typical example hereof is diphenylmethane-4,4-diisocyanate, further referred to as MDI and mixtures of the latter with its polymeric forms, which are usually applied for rigid

polyurethane foam manufacture. In certain cases, use can also be made of prepolymerized forms of MDI. In principle, each molecule containing active hydrogen groups such as : R-OH, R-COOH, R-SH, R₂-NH, R-NH₂, R-SH and others can serve as reaction substrate. Preferably, polyalcohols of the polyetherpolyol or the polyesterpolyol type or mixtures thereof serve as starting compounds, whereby polyetherpolyols, based on aromatic chain initiators, are furthermore preferred. These typically have a weight average molecular weight of at least 150, and preferably between 500 and 5000. The functionality is always higher or equal to 2 and typically have a hydroxyl number (OH) comprised between 25 and 1000. For the polyurethane preparation, typically an isocyanate is used with an index approaching the stoechiometric ratio, i.e. from 95 to 1 10 on active H functionality, whereas the polyisocyanurate preparation requires a much higher index in order to allow the trimerization reaction of the isocyanate as such. This isocyanate index is usually higher than 150. In order to obtain the foam structure, a chemical or physical blowing agent is employed. Usually water is added as chemical blowing agent, which liberates carbon dioxide in situ by reaction with the isocyanate. Typical physical blowing agents include low boiling organic liquids are used, which evaporate as a result of the urea, urethane and trimerisation reactions and contribute to the formation of the typical foam structure.

As foam stabilizers, ionic or non-ionic stabilizers are typically employed, such as N-vinyl-2-pyrrolidinone, dibutylmaleate, condensation products of alkylphenols with ethylene oxide, mono-, di- or tri-esters of condensation products of sorbitan with ethylene oxide. Preferably laurate, palmitate, stearate or oleate esters, condensation products of fatty acids with ethylene oxide, such as for example the condensation products of stearic acid with ethylene oxide; condensation products of alcohols with ethylene oxide, condensation products of amides with ethylene oxide, such as for example the

diethanolamine monostearate derivative condensed with 2 moles ethylene oxide; condensation products of amines with ethylene oxide, such as for example the products starting from oleylamine and ethylene oxide;

condensation products of mercaptane derivatives and ethylene oxide, preferably in amounts of 0.1 -10 parts by weight and more specifically 0.1 to 4 parts by weight per 100 parts by weight polyol.

Besides the non ionic stabilizers, also anionic or cationic stabilizers are appropriate. Suitable cationic components include amine acetate or

chlorohydrate salts, quaternary ammonium salts, pyridine and quinoline derivatives and derivatives of ethanolamines.

Suitable catalysts include tertiary amine compounds, such as for example N,N min -dimethylcyclohexylamine, diaminobicyclo-octane (DABCO), or metal , alkali metal or alkaline-earth metal salts of organic or anorganic origin, such as for example potassium octoate, dibutyltin dilaurate, and/or Sn- mercaptides. The amounts which are used here are dependent on the catalytic activity and are typically comprised between 0.01 and 10 parts by weight, and more specifically between 0.01 and 4 parts by weight, per 100 parts by weight polyol.

Extra additives, such as for example fire retardants, such as phosphor and halogen containing additives or polyols, smoke suppressors, additional cross-linkers, fillers, and/or diluents can always be added in order to give the final product certain specific features.

Preferably, the density of the particulate foam material is higher than 33 kg/m³, as determined according to ASTM D1622, more preferably above, 37, 60, 80, and most preferably above 120 kg/m³. It preferably has a thermal conductivity at +10°C (ASTM C 518) of at least 0.021 , preferably 0.029, 0.030, and more preferably 0.032 W/mK

Preferably, the particulate foam material is obtained by A) contacting an isocyanate and an active hydrogen containing compound, such as a polyol in the presence of a catalyst, a foam stabilizer and a blowing agent to obtaing a foam, and B) cutting or milling the foam to obtain shaped foam articles and the particulate foam material as cutting or milling waste.

Preferably, the particulate polyurethane foam has a closed cell content of at or above 90%, more preferably above 95%, as determined according to ASTM D 2856, Procedure A. It further preferably has a thermal conductivity of below according to ASTM C581 of Initial (10°C) 0,021 +/- 0,001 W/mK

and Aged (10°C) 0,026 +/- 0,001 W/mK.

It further preferably has a Compressive Strength (ASTM D1621 ) of above 160 kPa. It further preferably has a Tensile Strength (ASTM D1623) of above 180 kPa, all measured at the foam prior to cutting or grinding it to particulate matter.

The present invention thus makes use of only, or mostly state materials that otherwise might have to be incinerated, thereby improving the carbon footprint of the related chemical processes, while delivering a particularly good product with very low requirements.

A further particularly interesting component for use in the composite blends according to the present invention is fibrous material obtained from recycled car interiors Preferred suitable fibrous materials are the light fractions SLF (Shredder-Leichtfraktion); Rohflusen and/or Leichtflusen LF1 , LF2, and /or LF1 -LG disclosed in WO-A-2009/124651 , and/or Shredderflusen as disclosed in DE-A-19755629. These materials are fibrous fractions obtained from recycling automobiles after removal of metals and thermoplastics. The disclosed process comprises several steps: I) A first step in the recovery cycle removal of all suitable parts that may be refurbished or recycled selectively, such as e.g. the accumulator, tyres; catalytic converters and panes of glass where applicable, and optionally, thermoplastic and/or thermoset polymeric parts; II) a step for the removal of the automotive operating fluids, such as fuel; engine, gear, power steering and shock absorber oil; air conditioning

refrigerants as well as brake and coolant fluids; III) crushing the remaining bodywork and subjecting it to a grinding operation, preferably in a so-called shredder. This suitably grinds the remaining bodywork into pieces of just a few centimetres in size. At this stage, in a further step ferrous and non-ferrous metal parts are removed. In these first steps I to III, up to 80 % wt. of the scrap vehicle has been removed for recycling purposes, to obtain a fraction further referred to as shredder residue, which represents 20 %wt of the recycled car. This shredder residue is then subjected to a so-called the "VW- SiCon Process", wherein several fractions are gained from the shredder residue. The process thus further comprises subjecting the shredder residue is subjected to at least one further grinding step (IV), and to at least one separation step (V). The latter may advantageously be performed using one or more cyclones that separate material according to density. This process results in one or more fibrous fractions, all of which are suitable as fibrous material according to the subject process.

Preferably, the density of the fibrous material is of from 200 to 450 kg/m³ The density of the fibrous material is measured prior to incorporation into the composite. Preferably, the fibrous material comprises recycled car interior material.

More preferably, the fibrous material is produced in process comprising the steps of A) shredding a car body, and B) removing ferrous and/or non- ferrous metal, and C) separating the fibrous material from a heavier fraction and a lighter particulate fraction. Preferably, the fibrous material has a

Carbon content of above 45% wt., and a hydrogen content of above 5 %wt.. The thus obtained composite materials have a density of typically in between 800 and 1600 kg/m³, preferably of from 1 150 to 1500 kg/m³, and yet more preferably of from 1300 to 1400 kg/m³, such as 1350 kg/m³.

The composite material may further comprise further components, such as glass fibres, e.g. of 3 to 5 cm length. The composite material may also comprise additives, such as pigments, fillers, flow improvers, catalysts, wetting agents and other usually applied additives. These are suitably added in blending step a).

A particularly useful additive in the process and composites of the present invention is recycled ground hard polyurethane foam particles. These were found to improve the smoothness of the material and to improve the insulation properties, as well as to reduce density and weight while not affecting the mechanical strength.

The blending step (a) may be performed by any suitable method, including mechanical methods, and/or advantageously the use of cyclone technology, which may equally allow to pre-heat binder and fibrous material, as may be required for a continuous production. In such a line-up, the two materials, together with any additive or other material as required may be advantageously be blended and premixed from e.g. two silos, and then mixed intensively while already pre-heating to allow for an improved flow if a homogenous composite with a thermoset binder is desired. Alternatively, the process may be performed batch-wise. The benefit of such a batch production is the relative ease of heating and shaping, but equally also the fact that a less homogenous material may be obtained, which can be advantageous if porous matrix materials are present as well, whereby a full saturation of cavities in the matrix may be avoided, thereby maintaining high insulation values and low density.

In the process according to the invention, the blended material obtained in step (a) is preferably shaped prior to, or during the curing step, to obtain a shaped composite article.

Preferably, the process further comprises adding one or more woven or non-woven sheet material to at least one side of the composite blend prior to step (b). This maybe for simply decorative purposes, as well as UV filtration by using a pigmented or printed foil, or functional such as the use of glass or carbon fibre mats for increased strength.

Preferably the process further may comprise adding at least one porous polymeric matrix layer, preferably a rigid urethane foam layer, and applying the blended material to at least one side of the foamed polymeric matrix layer, prior to step (b). This will result in less dense composites with high insulation values.

The process according to the invention further preferably comprises heating the blended composite material such that the particulate binder material at the core of the blended material is flowing and curing.

The heating of the blended composite material may be done by any suitable heating means. According to a continuously operating embodiment of the invention, the blend of powder binder and powder PU material is pressed and heated from one or both sides, preferably pressed between a heated roll and a transportation belt, or more preferably, between heated rolls. According to another preferred embodiment, the composite to be cured is passed through a heating area, preferably through a furnace.

The composites may be formed by either a batch process or a continuous process. In a batch process, the components in the form are suitably blended together dry in the desired weight percentages. Blending may preferably occur within an extruder feed hopper or prior to the materials being introduced into the hopper via an appropriate mixing device, for example, a blender. The materials can also be fed into the hopper using vibratory feeders. The hopper then advantageously feeds the mixed material into a suitable extruder. Within the blender or extruder, the material may already be heated up, in particular in the case of thermoplastic binders, such that the binder enters a molten state. In the case of thermosetting binders, The blended material is then preferably discharged into a mold.

The composite material further preferably comprises a porous polymeric matrix layer, for increased thermal insulation. Preferably, when shaped into panels, the edges of the composite panel comprise a higher amount of the composite material to increase mechanic strength. The composite material preferably further comprises at least one woven or non-woven sheet layer, to improve the mechanical properties such as tensile strength and surface resilience. The composite material may further comprise a cover sheet material to create an exterior expression, such as coloured films, preferably also comprising a UV filter, printed films, printed paper or carton box, woven or non-woven fabrics.

According to a further preferred embodiment of the invention, the powder is heated by radiation, such as microwaves to ensure that the core of the composite material also is heated. Alternatively, and most easily, the process may be performed in a batch-wise operation, wherein the mold with the composite material is heated, advantageously in an oven. Preheating of the binder material or the blended material prior to introduction into the mold may also be performed, provided that in case of a thermoset binder, the heat supply should be limited to not allow the material to cure completely. This allows adapting the curing cycle to the particulate binder material. In the case of thermoplastic binders, the heat supply may be removed, and the mold may be cooled once the composite has been formed.

In the case of the thermoset binders the cure cycle requires that the particulate binders first melts and flows, while at the same time the curing begins.

Accordingly, the heating of the thermoset binder composite material will require a more cautious approach, and may require longer curing times with a temperature profile going to different temperature levels. One skilled in the art will easily determine the operating conditions, such as heating time, heating temperature, pressure, etc, as may be applicable. Preferably, the

increased temperature refers to a temperature in the range of from 190 to 350°C, preferably 120 to 280°C, yet more preferably 140 to 250°C. The pressure may be any pressure that is suitably applied, and may range from ambient pressure or slightly above that, such as the pressure exerted by a vacuum bag, to a pressure of several tons per square meter, as suitably applied by e.g. a hydraulic press. Preferably the pressure ranges of from 0.1 MPa to 10 MPa, preferably from 1 to 7 Mpa., again more preferably from 2 to 6.5 Mpa. The unit pressure applied to the molding material in a mold. The area is calculated from the projected area taken at right angles to the direction of applied force and includes all areas under pressure during the complete closing of the mold. The unit pressure, expressed in kg per square centimetre, is calculated by dividing the total force applied by this projected area. This is particularly suitable as a high-volume, high-pressure method suitable for a semi-continuous or continuous mode of operation. The time required to achieve a suitable strength and appearance depends largely on the kind of particulate binder used, but may range from several seconds, e. g. at high pressure and temperature, to several hours. Preferably, the time wherein the increased temperature and pressure are applied ranges of from 1 s to 10 hours, more preferably from 5 s to 5 h, yet more preferably from 30 s to 3 h, again more preferably from 1 min to 1 h. Furthermore, the material may be pre-heated, and/or postcured as required.

The process of the invention is applicable to any kind of powder coating composition. As far as mixtures of two or more compositions are concerned, their compatibility should be evaluated first.

The present invention further relates to the use of the optionally shaped composite article as building or sheet material, as decorative and/or functional panelling, e.g. as noise suppression walls.

The present invention also relates to the composite material comprising a particulate polyurethane foam material and a particulate binder, wherein the PU material preferably has a density of above 33 kg/m³, according ASTM 1622, more preferably a compressive strength of at or above 210 kPA according to ASTM D17623 prior to incorporation into the composite material, and wherein the binder material is a particulate binder having an average particle size (D90) of from 15 to 850 pm prior to incorporation into the composite, as obtainable by the subject process. The composite material preferably has a flame spread index of B-S3 or better according to EN 13501 - 1 :2007.

The composite material is resistant to attack by microbes and insects and thus does not require expensive chemical treatments. Also, the material is resistant to degradation from exposure to ultraviolet light as well as damp, freezing conditions. The present invention further preferably relates to a shaped article comprising the composite material according to the invention, such as advantageously in the form of a flat, square-shaped panel module for use in assembling building structures. Such panels may also advantageously be employed as replacement for fibre enforced concrete panels in structural or other outdoor applications, such as sound proofing, as at the side of highly frequented roads.

The following examples are provided to exemplify the invention.

Example 1

As a particulate binder material, waste epoxy powder coating material was employed, further referred to as powder waste. As a particulate foam material, dust and flakes obtained as waste material from cutting and sawing a polyurethane foam according to Table 1 was employed, further referred to as PU waste.

Table 1 : Polyurethane - polyisocyanurate foam blown

The two materials were intimately blended in a bucket, using a paint blender mounted on an electric drill, in a volume ratio of 3 volume parts of the PU waste on 1 volume part powder waste. All ratios or measures herein, if not otherwise indicated, are by weight. A simple metal mold comprising two metal plates was employed.

The metal plates were covered with siliconized paper, then the blended composite material. The mold was placed in a vacuum bag.

Subsequently, the thus layered material was pressed between two metal plates by applying vacuum to a layer thickness of about 18 mm, at a pressure equivalent to 4.5 kg/cm². Then the assembly was heated to a temperature of 140°C, and then maintained at this temperature for a period of 60 minutes.

After allowing the plates to cool, the thus obtained composite panel of about 600 kg/m³ density was subjected to a number of tests, including a flame propagation test according to NEN 6065 and a humidity test by submersing the plates in boiling water and measuring the weight gain.

The plates had sufficient mechanical properties and showed no significant weight gain upon immersion for several hours.

Example 2

A second plate was prepared, however using 1 ,5 volume parts of PU waste, 1 ,5 volume parts of a fibrous material as described herein below, and 1 volume part powder waste. The process resulted in a strong plate of 18 mm thickness and a density of from 900-1000 kg/m³ .

The fibrous material was obtained according to a process as disclosed in WO- A-2009/124651 , specifically fraction LF1 , i.e. the light fraction after removal of metals and thermoplastics. The fibrous material had the following properties (table 2): Table 2: Compositional data of the fibrous material (AAS)

Unit Component

Ppm Aluminium 14,637

Ppm Antimony 301

Ppm Arsenic 10

Ppm Barium 1 ,249

Ppm Beryllium 0.1

Ppm Bismuth 5.2

Ppm Boron 90

Ppm Cadmium 16

Ppm Calcium 13,700

Ppm Chromium 187

Ppm Cobalt 17

Ppm Copper 9, 189

Ppm Gallium 2

Ppm Iron 27,400

Ppm Kalium n.d.

Ppm Lanthanum 6

Ppm Lead 2,572

Ppm Lithium 12

Ppm Magnesium 2, 157

Ppm Manganese 524

Ppm Mercury 0.8

Table 2 (continued): Compositional data of the fibrous material (AAS)

Ppm Molybdenum 25

Ppm Natrium n.d.

Ppm Nickel 151

Ppm Niobium 3

Ppm Potassium 733

Ppm Rubidium 4.9

Ppm Scandium 0.8

Ppm Selenium 0.3

Ppm Sodium 1 ,641

Ppm Strontium 89

Ppm Silver 9

Ppm Silicon 14,050

Ppm Thallium 0

Ppm Thorium 1

Ppm Tin 151

Ppm Titanium 914

Ppm Tellur n.d.

Ppm Tungsten 1 1

Ppm Uranium 0

Ppm Vanadium 16

Ppm Yttrium 2

Ppm Zinc 5,634

Ppm Zirconium 42

Weight %ds Bromine 0.03

Weight %ds Fluorine 0.01

weight%ds Chlorine 1 .61

weight%ds Sulphur 0.23 Table 2 continued: Physical measurements

All ratios or measures herein, if not otherwise indicated, are by weight. Example 3: Fire retardancy

This test is performed according to EN-13501 -1 :2007, a standard test method for flame propagation in building materials. This test serves to determine the relative surface flammability and smoke performance of various materials under specific test conditions as well as the some development. The test results showed that all composite panels prepared according to example 1 and 2 obtained a B-S3 classification or better.

The examples above clearly show the advantages of the process and materials of the present invention. Although several specific embodiments of the present invention have been described in the detailed description above, this description is not intended to limit the invention to the particular form or embodiments disclosed herein since they are to be recognised as illustrative rather than restrictive, and it will be obvious to those skilled in the art that the invention is not limited to the examples.

Claims

1 . A process for the preparation of a composite material from a particulate binder material having an average particle size (D90) of from 15 to 850 pm and a particulate polyisocyanurate and/or polyurethane foam having a closed cell content of at or above 90%, as determined according to ASTM D 2856, Procedure A, comprising the steps of:

a) blending the particulate binder material and the particulate foam material, preferably in a volume ratio of 60:40 to 10:90 , and

b) subjecting the blended material obtained in a) to a curing step under increased temperature and pressure to obtain a composite material.

2. Process according to claim 1 , wherein the density of the particulate foam material is higher than 33 kg/m³, as determined according to ASTM D1622.

3. Process according to claim 1 or claim 2, wherein the particulate foam material is obtained by

A) contacting an isocyanate and an active hydrogen containing compound, such as a polyol in the presence of a catalyst, a foam stabilizer and a blowing agent to obtain a foam, and

B) cutting or milling the foam to obtain shaped foam articles and the particulate foam material as cutting or milling waste.

4. Process according to any one of claims 1 to 3, wherein the particulate binder material comprises a thermoset polymeric material, preferably a powder coating material that was collected as overspray from at least one powder coating application.

5. A process according to any one of the previous claims, wherein the particulate binder material comprises waste powder coating material obtained from overspray and/or powder coating production.

6. A process according to any one of the previous claims, further comprising shaping the blended material obtained in step (a) prior to or during the curing step, to obtain a shaped composite article.

7. A process according to any one of the previous claims, further comprising adding a woven or non-woven sheet material to at least one side of the composite blend prior to step (b).

8. Process according to any one of the previous claims, further comprising providing at least one porous polymeric matrix layer, preferably a rigid urethane foam layer, and applying the blended material to at least one side of the foamed polymeric matrix layer, prior to step (b).

9. A process according to any one of the previous claims, further comprising heating the blended composite material such that the particulate binder material at the core of the blended material is flowing and curing. 9. A process according to any one of the previous claims, further comprising adding and a fibrous material having a density of from 150 to 550 kg/m³ to the particulate binder material and the particulate foam material.

10. A process according to claim 9, wherein the fibrous material is obtained comprising the steps of

A) shredding a car body, and

B) removing at least part of the ferrous and/or non-ferrous metal, and

C) separating the fibrous material from a heavier fraction and a lighter particulate fraction.

1 1 . Process according to claim 9 or 10, wherein the fibrous material has a carbon content of above 45% wt., and a hydrogen content of above 5 %wt..

12. Use of the shaped composite article according any one of the previous claims as building or sheet material.

13. A composite material comprising a binder and a particulate

polyisocyanurate foam, and preferably, a fibrous material having a density of from 150 to 550 kg/m³, wherein the binder material is a particulate binder having an average particle size (D90) of from 15 to 850 pm prior to

incorporation into the composite.

14. A composite material according to claim 13, having a flame spread index of B-S3 or better according to EN 13501 -1 :2007.

15. The composite material according to claim 13 or 14, wherein the particulate polyurethane foam material comprises waste polyurethane powder material.

16. The composite material according to any one of claims 13 to15, wherein the binder is a thermoset binder.

17. The composite material according to claim 16, wherein the binder comprises waste powder coating material.

18. The composite material according to any one of claims 13 to 17, further comprising a porous polymeric matrix layer.

19. The composite material according to any one of claims 13 to 18, further comprising at least one woven or non-woven sheet layer.

20. A shaped article comprising the composite material according to any one of claims 13 to 19.

21 . A flat, square-shaped panel module for use in assembling building structures according to claim 20.

22. Use of a composite material according to claims 13 to

19 or a shaped article according to claims 20 or 21 as building material or panelling.