FIELD OF THE INVENTION

[0001] The present invention relates to a flame retardant as well as to an intumescent compound that can be used e.g. alone or in form an intumescent coating. Provided are also a plastic material and a fabric that include the flame retardant. Further provided are a method of rendering solid matter flame-resistant and a method of forming a flame- resistant plastic material or fabric. Furthermore a method of forming a carbonized material is provided.

BACKGROUND OF THE INVENTION

[0002] A large majority of materials used in every day life are at risk of burning and thus need protection from fire in order to prevent injuries, loss of life and other material damages. One of the strategies often employed to avoid damages from fire is to prevent the spread of fire by using fire resistant materials including intumescents. Burnable material is doped or coated with a respective flame retardant in various dosages depending upon its effectiveness. Such additives decompose on severe heating to form an incombustible or low combustible residue and typically generate gases.

[0003] There are two major classes of additives which are commonly employed as flame retardants. The first and the earliest class of additives used were halogenated organic compounds, in particular brominated aromatic compounds like polybrominated biphenyls and diphenyl ethers. There are many disadvantages associated with this class of flame retardants, viz. they are toxic, they retard fire only in the vapour phase, they produce toxic and corrosive gases when exposed to fire, they do not suppress smoke, they act as plasticizers and some of them are classified as persistent organic pollutants. Because of these reasons, this class of additives are banned in many developed countries. In order to overcome some of the disadvantages associated with the halogenated organic compounds, the second class of additives based on phosphorus and nitrogen containing compounds was developed. These compounds retarded fire by forming char which acted as a blanket, thereby shielding fuel, which is the combustible surface, from oxygen and fire. The disadvantages of this class of additives are that the char formed is unstable and also that they liberate phosphorus and nitrogen containing toxic gases when exposed to fire. The phosphate esters also act as plasticizers thereby enhancing dripping hazard, which can lead to burn injuries. Thus, there is a demand for a suitable material which could form stable char without liberating toxic gases when exposed to fire.

[0004] High char forming materials are also useful in many ways, the char itself being useful as adsorbents, to make ceramic materials like carbides, to form fibers, to make composites and as electrode materials in energy storage devices like batteries. Intumescence, which is the ability of materials to expand against heat, is a result of high char forming tendency of materials. Coatings that display intumescence, which are known as intumescent coatings, have wide applications. Intumescent coating is a mixture of five performance additives. These additives are: acid generator, co-generator, char former, blowing agent and cooling agent. The commonly employed carbonisation compounds/ char formers are pentaerythritol, dipentaerythritol and cellulose. Halogenated organic compounds such as chlorinated paraffin are used as co-generators. Nitrogen containing compounds such as melamine are used as blowing agents. A commonly employed cooling agent is hydrated alumina. These additives have to act in conjunction in order to have a successful voluminous or expandable char formation. For example, the acid generator forms an acid, which induces a chemical reaction in the char former to generate char. The char thus formed is made voluminous or expandable by the blowing agent that decomposes to form gases. The cooling agent helps to cool the surface by sudden release of water. Thus, intumescence in such coatings is a result of intermolecular heterogeneous reaction taking place on a solid surface and hence there are many uncertainties in such a process. For example, the components could escape the surface even before combining with each other due to volatilization caused by fire. The intumescence may not occur to. the extent desirable due to the likelihood of component migration caused by the heat. Since some of the components used are nitrogen based, toxic gas evolution still occurs. It is advantageous to overcome these issues by rendering the process of char formation intramolecular. It is also advantageous if the char formation is induced due to the heat caused by the fire itself rather than by additional components.

[0005] Accordingly, in confined spaces like modem day buildings, there exist choking hazards because of the evolution of toxic gases from flame retardants and intumescent coatings when they are exposed to fire. It would therefore be desirable to have flame retardants and intumescent coatings which do not eliminate harmful gases when heated or when coming into contact with fire. It would further be advantageous if such flame retardants would prevent the spread of fire by char formation. It would also be advantageous to have a further method of forming polymers which are useful as intumescent additives. In this regard it would further be desirable to be able to make polymers which form char with variable surface areas.

[0006] It is therefore an object of the invention to provide a method of rendering solid matter flame resistant and a method of forming a flame resistant plastic material, fabric or wood/wood based material that avoids at least some of the above discussed drawbacks or shortcomings. This object is solved by the methods of the independent claims.

SUMMARY OF THE INVENTION [0007] In a first aspect the invention provides a flame retarding additive. The flame retarding additive includes or consists of a poly(arylalkyl ketone) as described in US Patent 7,034,187. The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ )n-C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ )n-C(0)-] n is 1 or 2. The flame-retarding additive is included in a plastic material, a fabric or a coating composition.

[0008] X may in some embodiments be one of H, -OH, -OR, -NH ₂ , -NHR, -NR ₂ and alkyl. In -OR, -NHR, -NR ₂ the moiety R is an alkyl group with a main chain of 1 to 6 carbon atoms.

[0009] In some embodiments the flame-retarding additive is included in the plastic material, the textile or the coating composition in an amount selected in the range from about 1 to about 20 wt%.

[0010] In a second aspect the inventions provides an intumescent coating. The intumescent coating includes or consists of a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2.

[0011] In some embodiments X may for example be one of H, -OH, -OR, -NH ₂ , -NHR, -NR ₂ and alkyl. In -OR, -NHR, -NR ₂ the moiety R is an alkyl group with a main chain of 1 to 6 carbon atoms.

[0012] In some embodiments the intumescent coating includes the poly(arylalkyl ketone) in an amount selected in the range from about 5 to about 15 wt%

[0013] In a third aspect the invention provides a plastic material. The plastic material includes a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ )n-C(0)-] n is 1 or 2.

[0014] In some embodiments X may for example be one of H, -OH, -OR, -NH ₂ , -NHR, -NR ₂ and alkyl. In -OR, -NHR, -NR ₂ the moiety R is an alkyl group with a main chain of 1 to 6 carbon atoms.

[0015] In some embodiments the plastic material includes the poly(arylalkyl ketone) in an amount selected in the range from about 1 to about 20 wt%.

[0016] In a fourth aspect the invention provides a fabric. The fabric includes a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2.

[0017] In some embodiments X may for example be one of H, -OH, -OR, -NH ₂ , -NHR, -NR ₂ and alkyl. In -OR, -NHR, -NR ₂ the moiety R is an alkyl group with a main chain of 1 to 6 carbon atoms.

[0018] In some embodiments the fabric includes the poly(arylalkyl ketone) in an amount selected in the range from about 1 to about 20 wt%. [0019] In a fifth aspect the invention provides a treated wood or wood based material. The wood or wood based material includes a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2.

[0020] In a sixth aspect the invention relates to the use of a poly(arylalkyl ketone) as/in a flame retardant or as/in an intumescent coating. The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ )n- in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2.

[0021] In some embodiments X may for example be one of H, -OH, -OR, -NH ₂ , -NHR, -NR ₂ and alkyl. In -OR, -NHR, -NR ₂ the moiety R is an alkyl group with a main chain of 1 to 6 carbon atoms.

[0022] In some embodiments the poly(arylalkyl ketone) is a flame-retarding additive in one of a plastic material, a textile, wood or wood based material or a coating composition.

[0023] In a seventh aspect the invention provides a method of rendering solid matter flame-resistant. The method includes providing a poly(arylalkyl ketone) or composition that includes the poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ )n- in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n - C(O)-] n is 1 or 2. The method also includes applying the poly(arylalkyl ketone), or the composition that includes the same, to the solid matter.

[0024] In some embodiments applying the poly(arylalkyl ketone) or the corresponding composition is or includes coating the solid matter with the poly- (arylalkyl ketone) or the composition that includes the same. Thereby an intumescent coating is formed.

[0025] In an eighth aspect the invention provides a method of forming a flame- resistant plastic material or fabric. The method includes providing a suitable organic polymer compound. The method further includes providing a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ )n-C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2. Furthermore, the method includes admixing the poly(arylalkyl ketone) to the organic polymer compound. Thereby a mixture is formed. The method also includes molding and/or extruding the mixture. Thereby the flame-resistant plastic material or fabric is obtained.

[0026] In a ninth aspect the invention provides a method of rendering a plastic material, fabric wood or wood based material flame-resistant. The method includes providing a poly (arylalkyl ketone) or composition that includes the poly (arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar- (CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2. The method also includes impregnating the plastic material, fabric wood or wood based material with the poly(arylalkyl ketone) or the composition that includes the same.

[0027] In a tenth aspect the invention provides a method of forming a carbonized material. The method includes exposing a poly(arylalkyl ketone) to pyrolysis. Exposure to pyrolysis is carried out under inert atmosphere, and at a temperature in the range from about 600 °C to about 3000 °C. The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula ar is an aromatic, arylaliphatic or arylalicyclic moiety with a main chain of 5 to about 36 carbon atoms and 0 to 2 heteroatoms. X is selected from a group of substituents so that the group -(CX ₂ ) _n - in this formula is an electron donating group providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. In general formula [-ar-(CX ₂ ) _n -C(0)-] n is 1 or 2.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings.

[0029] Figure 1 shows examples of poly(arylalkyl ketone) compounds suitable as according to the invention. G is one of C¾, O, S and NH. Y and Z are independently from each other one of CH, O, S, and N.

[0030] Figure 2 illustrates the TGA of polymers.

[0031] Figure 3 depicts the proposed char forming mechanism in substituted chloral (BPC) and deoxybenzoin (DOB) (Ellzey, KA, Macromolecules (2006) 39, 3553-3558).

[0032] Figure 4 depicts the TGA of poly(arylalkyl ketone).

[0033] Figure 5 is a table of a selected list of antiflammable polymers (Ranganathan, T, et al., Macromolecules (2006) 39, 5974; Walters, RN, et al., J. Appl. Polym. Sci. (2003) 87, 548).

[0034] Figure 6 shows a comparison of the TGA of PAK and APP.

[0035] Figure 7 depicts the elimination of water during pyrolysis of PAK. The curve depicts elimination of water.

[0036] Figure 8 depicts the results of the British Standard 476 Part 7 test.

[0037] Figure 9 depicts the proposed water and char forming mechanism in PAK.

[0038] Figure 10 depicts a comparative analysis of a fire retardant additive in terms of flame retardancy.

[0039] Figure 11 depicts a comparative analysis in terms of intumescent performance.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Halogen based flame retardants are banned in many parts of the world due to their deleterious effect on the environment. Organic compounds that undergo chemical transformations upon heating to yield highly unsaturated intermediates generally form char and are thereby useful as flame retardants. For example, polymers derived from the bisphenol of chloral, [l,l-dichloro-2,2-(4-hydroxyphenyl)ethane], (BPC) show exceptionally good fire resistance due to the formation of char (Stoliarov, SI, et al., Polymer (2003) 44, 5469; Mouries, V, et al. Synthesis (1998) 3, 271). Deoxybenzoin (DOB) has also been reported to form char in high quantities when heated in the presence of silica-alumina catalyst (van der Waals, ACLM, et al., J. Mol. Cat. A (1998) 134, 179). The mechanism given in Fig. 3 has been proposed for the formation of high amounts of char in BPC and DOB.

[0041] However, there are drawbacks in both cases. Since chloral is a chlorinated organic compound, it forms chlorine containing gases upon heating thereby creating a scenario which is similar to halogenated flame retardants. In the case of deoxybenzoin, even though it eliminates water upon heating which is not disadvantageous but desirable, the process requires some catalyst and is not spontaneous. Also, in both cases comonomers are required to form a polymer since they do not homo- or self- polymerize. Due to the presence of comonomers, the effective concentration of char forming component is lowered and thus also the quantity of char formed. Thus, there is a requirement for flame retardant materials which can self-polymerize and spontaneously form char in appreciable quantities upon heating or when exposed to fire without the elimination of toxic gases. Flame retardants act by interfering with the combustion process of polymers or other materials.

[0042] "To intumesce" means to "grow and to increase in volume against heat" or "to show an expanding effect by bubbling". When heating beyond a critical temperature, intumescent materials begin to swell and then to expand. The result of this process is a foamed cellular charred layer on the surface which protects the underlying material from the action of heat or flame. The charred layer acts as a physical barrier which slows down heat transfer. Intumescents are generally materials that undergo a series of chemical reactions when exposed to heat, in particular temperatures of more than about 200 °C. The reactions lead to the formation of incombustible carbonaceous residues called "char". Ideally a layer of char is formed. Due to the thermal insulation properties of char such a layer may be regarded as an insulating layer, which insulates the underlying substrate from conducted heat and thus, prevents or decreases thermal damage to the substrate. An intumescent system can be taken to interrupt self-sustained combustion of e.g. a polymer at its earliest stage, the thermal degradation with evolution of gaseous fuels. In addition, the char layer retards flame spread by hindering the flow of combustible gases about the substrate.

[0043] Intumescent materials presently used in the art typically contain a plurality of ingredients that undergo reactions with each other upon exposure to heat. Some of these components decompose on severe heating while others can act catalytically, e.g. a strong Branstedt acid, and yet others act as a blowing agent, forming gas that assists in the formation of a foam layer of char. The latter can, however, involve the release of toxic gases.

[0044] In the present invention a polymer is used as flame retarding matter, as an additive, as an impregnating agent, as a component, as well as a surface coating or in a formulation of a surface coating. In any embodiment, including use or method, of the invention the polymer may be employed in its pure form or in an at least essentially pure form. The polymer may for example be more than 95 %, more than 97 %, more than 98 %, more than 99 % or more than 99.5 % pure. The polymer may also be an ingredient of a composition. In either case the polymer or the respective composition may be used as a coating agent, as an impregnating agent or to be otherwise applied to a substrate, which is to be rendered flame resistant. Methods of impregnating a substrate, e.g. by techniques of immersion, dipping, trickling or casting, are well established in the art.

[0045] When used as/in a flame retardant or as/in an impregnating agent the polymer is in some embodiments included in a composition. In such a composition the polymer may, in some embodiments, be present in an amount of about 1 wt% to about 20wt%, including in the range from about 1 wt% to about 15 wt%, about 2 wt% to about 15 wt%, about 1 wt% to about 12 wt%, about 2 wt% to about 12 wt%, about 3 wt% to about 15 wt%, about 3 wt% to about 12 wt%, about 3 wt% to about 10 wt%, about 3 wt% to about 10 wt%, from about 3 to about 8 wt% and from about 3 to about 6 wt%. When used as a flame retardant the polymer can in some embodiments be used in doses that are low compared to conventional additives as a flame retardant. While commercial flame retardants are typically applied in the range of 10 to 15 wt%, a polymer of the invention can often be used in amounts below 10 wt%, such as in the range of about 3, about 4, about 5, about 6, about 7 or about 8 wt%, albeit it may also be applied in higher amounts.

[0046] A composition that includes the polymer may include one or more further components such as a synergist that increases the effectiveness of char formation, a spumific agent that will blow the char up into the form of a foam, or a charring catalyst that increases the rate of charring. Suitable synergists include melamine polyphosphate, ammonium polyphosphate and nitrogen gas emitting material. Illustrative examples of a suitable spumific agent (blowing agent) are an amine, an amide, melamine, dicyandi- amide, or urea. A suitable catalyst may be a material that emits boric, phosphoric or sulfuric acid during the burning process which combines with matter that is to be protected, e.g. a polymer, thereby forming char. Illustrative examples of a catalyst are phosphorous compounds, such as ammonium phosphate and phosphate esters, aromatic boronic acids and boron compounds. As also explained below, the use of a polymer according to the invention does not depend on any such additional components of a composition. A polymer according to the invention does for example not depend on the presence of an acid to cause dehydation. Hence ammonium polyphosphate and chlorinated paraffin need not be added to a composition that includes a polymer according to the invention. The high char forming nature (vide infra) also renders adding a polyol redundant in a respective composition. Further flame retardants present in the composition may, however, require such components to be included in order to be able to show a flame retarding effect themselves. A respective composition may accordingly also include a further flame retardant such as a condensed-phase active flame retardant or a volatile-phase active flame retardant. A condensed-phase active flame retardant facilitates charring by reducing or limiting the amount of fuel available to a fire. A volatile-phase active flame retardant inhibits the combustion process by reducing heat released during combustion.

[0047] When used as an intumescent additive or as a component in an impregnating composition the polymer is in some embodiments present in an amount of about 1 wt% to about 30wt%, including in the range from about 1 wt% to about 25 wt%, from about 2 wt% to about 25 wt%, about 2 wt% to about 23 wt%, about 2 wt% to about 20 wt%, about 3 wt% to about 25 wt%, about 3 wt% to about 20 wt%, about 3 wt% to about 15 wt%, about 4 wt% to about 15 wt%, about 5 wt% to about 15 wt%, from about 5 to about 12 wt% and from about 5 to about 10 wt% or from about 5 wt% to about 8 wt%, including about 6 wt% or about 7 wt%. Accordingly, when used as an intumescent additive the polymer can in some embodiments be used in doses that are low compared to conventional additives in intumescent coatings. Commercial additives in intumescent coatings are typically applied in the range of 15 to 25 wt%, whereas a polymer of the invention can often be used in amounts below 15 wt%, including in amounts below 10 wt%, albeit it may also be applied in higher amounts. It is noted that in commercial intumescent coatings, brominated compounds are mainly used as acid generators.

[0048] An intumescent coating composition that includes the polymer of the invention may, for example, be used to protect a steel supported structure such as structural steel components in buildings against the effects of any fire conditions known to the art, e.g. cellulosic, hydrocarbon and/or Jetfire conditions. The char formed (vide infra) greatly reduces the rate of heating experienced by the steel, thus extending the time before the steel loses its integrity and the building/structure collapses, thereby allowing additional time for safe evacuation.

[0049] The polymer used in the invention is a poly(arylalkyl ketone). The poly(arylalkyl ketone) has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. Without wishing to be bound by theory, the presence of the carbonyl group is believed to be somehow essential for char formation, as also explained below and depicted in Fig. 9. In conjunction with one or more units (CX ₂ ) the carbonyl group allows for an equilibrium with its enol form. As an illustrative example, the group -CH(Me)-C(0)- is in an equilibrium with the group -C(Me)=C(OH)-. Thereby, the formation of water upon exposure to fire is possible.

[0050] In the general formula above ar is one of an aromatic, an arylaliphatic and an arylalicyclic moiety. The term "aromatic" means, unless otherwise stated, an at least essentially planar cyclic hydrocarbon moiety of conjugated double bonds, which may be a single ring or include multiple condensed (fused) or covalently linked rings, for example, 2, 3 or 4 fused rings. The term aromatic also includes alkylaryl. Typically, the hydrocarbon (main) chain includes 5, 6, 7 or 8 main chain atoms in one cycle. Examples of such moieties include, but are not limited to, cyclopentadienyl, phenyl, napthalenyl-, [10]annulenyl-(l,3,5,7,9-cyclodecapentaenyl-), [12]annulenyl-, [8]annulenyl-, phenale- ne (perinaphthene), 1,9-dihydropyrene, chrysene (1,2-benzophenanthrene). An example of an alkylaryl moiety is benzyl. The main chain of the cyclic hydrocarbon moiety may, unless otherwise stated, be of any length and contain any number of heteroatoms, as for instance N, O and S. Such a hetero aromatic moiety may for example be a 5- to 7- membered unsaturated heterocycle that has one or more heteroatoms from the series O, N, S. Examples of such hetero aromatic moieties (which are known to the person skilled in the art) include, but are not limited to, furanyl-, thiophenyl-, naphtyl-, naphthofuranyl-, anthrathiophenyl-, pyridinyl-, pyrrolyl-, quinolinyl, naphthoquinolinyl-, quinoxalinyl-, indolyl-, benzindolyl-, imidazolyl-, oxazolyl-, oxoninyl-, oxepinyl-, benzoxepinyl-, azepinyl-, thiepinyl-, selenepinyl-, thioninyl-, azecinyl-, (azacyclodecapentaenyl-), diaze- cinyl-, azacyclododeca-1,3,5,7, 9,l l-hexaene-5,9-diyl-, azozinyl-, diazocinyl-, benzazo- cinyl-, azecinyl-, azaundecinyl-, thia[l l]annulenyl-, oxacyclotrideca-2,4,6,8,10,12- hexaenyl- or triazaanthracenyl-moieties.

[0051] Accordingly, in some embodiments the moiety ar may be benzole, imidazole, benzimidazole, 4H-pyran, pyrazole, pyrazine, pyridazine, furan, thiophen, benzofuran, pyridine, bipyridine, indole, 2H-iso indole, naphthalene, anthracene, 9,10- anthracenedione, quinoline, isoquinoline, quinazoline, cinnoline, quinoxaline, thiazine, thiazole, isothiazole, lH-azepine, dibenzopyridine, azocine, lH-azonine, oxepine, thiepine, thiaphanthrene (naphtho[2,3-b]thiophene), phenanthro[3,2-b]thiophene, 1-oxa- lH-benz[fJindene (naphtho[2,3-b]furan) and furo[3,2-b]pyridine.

[0052] The term "aliphatic" means, unless otherwise stated, a straight or branched hydrocarbon chain, which may be saturated or mono- or poly-unsaturated and include heteroatoms. The term "heteroatom" as used herein means an atom of any element other than carbon or hydrogen. An unsaturated aliphatic group contains one or more double and/or triple bonds (alkenyl or alkinyl moieties). The branches of the hydrocarbon chain may include linear chains as well as non-aromatic cyclic elements. The hydrocarbon chain may, unless otherwise stated, be of any length, and contain any number of branches. Typically, the hydrocarbon (main) chain includes 1 to about 5, to about 10, to about 15 or to about 20 carbon atoms. Examples of alkenyl radicals are straight-chain or branched hydrocarbon radicals which contain one or more double bonds. Alkenyl radicals generally contain about two to about twenty carbon atoms and one or more, for instance two, double bonds, such as about two to about ten carbon atoms, and one double bond. Alkynyl radicals normally contain about two to about twenty carbon atoms and one or more, for example two, triple bonds, preferably such as two to ten carbon atoms, and one triple bond. Examples of alkynyl radicals are straight-chain or branched hydrocarbon radicals which contain one or more triple bonds. Examples of alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, the n isomers of these radicals, isopropyl, isobutyl, isopentyl, sec-butyl, tert-butyl, neopentyl, and 3,3-dimethylbutyl. Both the main chain as well as the branches may furthermore contain heteroatoms as for instance N, O, S, Se or Si or carbon atoms may be replaced by these heteroatoms.

[0053] The term "alicyclic" may also be referred to as "cycloaliphatic" and means, unless stated otherwise, a non-aromatic cyclic moiety (e.g. hydrocarbon moiety), which may be saturated or mono-or poly-unsaturated. The cyclic hydrocarbon moiety may also include fused cyclic ring systems such as decalin. The cyclic hydrocarbon moiety may also be substituted with non-aromatic cyclic as well as chain elements. The main chain of the cyclic hydrocarbon moiety may, unless otherwise stated, be of any length and contain any number of non-aromatic cyclic and chain elements. Typically, the hydrocarbon (main) chain includes 3, 4, 5, 6, 7 or 8 main chain atoms in one cycle. Examples of such moieties include, but are not limited to, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl. Both the cyclic hydrocarbon moiety and, if present, any cyclic and chain substituents may furthermore contain heteroatoms, as for instance N, O, S, Se or Si, or a carbon atom may be replaced by these heteroatoms. The term "alicyclic" also includes cycloalkenyl moieties that are unsaturated cyclic hydrocarbons, which generally contain about three to about eight ring carbon atoms, for example five or six ring carbon atoms. Cycloalkenyl radicals typically have a double bond in the respective ring system. Cycloalkenyl radicals may in turn be substituted. Examples of such moieties include, but are not limited to, cyclohexenyl, cyclooctenyl or cyclodecenyl.

[0054] By the term "arylaliphatic" is meant a hydrocarbon moiety, in which one or more aromatic moieties are substituted with one or more aliphatic groups. Thus the term "arylaliphatic" also includes hydrocarbon moieties, in which two or more aryl groups are connected via one or more aliphatic chain or chains of any length, for instance a methylene group. Typically, the hydrocarbon (main) chain includes 5, 6, 7 or 8 main chain atoms in each ring of the aromatic moiety. Examples of arylaliphatic moieties such as alkylaryl moieties include, but are not limited, to 1 -ethyl-naphthalene, Ι,Γ- methylenebis-benzene, 9-isopropylanthracene, 1,2,3-trimethyl-benzene, 4-phenyl-2- buten-l-ol, 7-chloro-3-(l-methylethyl)-quinoline, 3-heptyl-furan, 6-[2-(2,5-diethyl- phenyl)ethyl]-4-ethyl-quinazoline or, 7,8-dibutyl-5,6-diethyl-isoquinoline.

[0055] The term "arylalicyclic" refers to an alicyclic moiety that is substituted with one or more aromatic groups. The term "arylalicyclic" also includes hydrocarbon moieties, in which two or more aryl groups are connected via one or more alicyclic ring(s), which may have any ring size and a main chain of any length. Generally the hydrocarbon (main) chain of an arylalicyclic moiety includes more than about 4 main chain atoms, and typically 5, 6, 7, 8 or 10 main chain atoms in each ring of the alicyclic moiety. Typically, the hydrocarbon (main) chain includes 5, 6, 7 or 8 main chain atoms in each ring of the aromatic moiety. Two illustrative examples of an arylalicyclic moiety are phenylcyclohexyl and phenylcyclopentyl.

[0056] Each of the terms "aliphatic", "alicyclic", "aromatic", "arylalicyclic" and "arylaliphatic" as used herein is meant to include both substituted and unsubstituted forms of the respective moiety. Substituents may be any functional group, as for example, but not limited to, amino, amido, azido, carbonyl, carboxyl, cyano, isocyano, dithiane, halogen, hydroxyl, nitro, organometal, organoboron, seleno, silyl, silano, sulfonyl, thio, thiocyano, trifluoromethyl sulfonyl, p-toluenesulfonyl, bromobenzene- sulfonyl, nitrobenzenesulfonyl, and methanesulfonyl.

[0057] A heteroatom is any atom that differs from carbon. Examples include, but are not limited to N, O, P, S, and Se. Where several heteroatoms are present within, for instance the one or more rings of the aromatic moiety or of a respective arylalicyclic, they are independently selected.

[0058] The aromatic, arylaliphatic or arylalicyclic moiety "ar" in the general formula [-ar-(CX ₂ ) _n -C(0)-] has in some embodiments a main chain of 5 to about 36 carbon atoms, such as 5 to about 30 carbon atoms, 5 to about 25 carbon atoms, 5 to about 20 carbon atoms, 5 to about 18 carbon atoms, 5 to about 16 carbon atoms, 5 to about 15 carbon atoms or 5 to about 12 carbon atoms, including e.g. 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 carbon atoms. The main chain of this aromatic, arylaliphatic or arylalicyclic moiety may further have 0 to about 8 heteroatoms, such as 0 to about 6, 0 to about 4, 0 to about 3 or 0 to 2 heteroatoms, including one heteroatom. A respective heteroatom may for instance be N, O, S, Se or Si.

[0059] As already indicated above, the aromatic, arylaliphatic or arylalicyclic moiety can also be optionally substituted, i.e. one or more hydrogen atoms of an aromatic ring can be replaced by other groups. Such other groups may be present on the aromatic ring as long as these groups do not interfere with the ketone forming polymerization reaction but having a positive influence on the reaction process. As disclosed in US Patent 7,034,187 the poly(arylalkyl ketone) can be formed reacting one or more arylalkanoic acids in the presence of an alkane or aryl sulfonic acid and a condensing agent. Without wishing to be bound by theory, it is believed that in terms of reaction mechanism the formation of a polymer according to the present invention proceeds by electrophilic attack on the aromatic ring of the arylalkanoic acids. It is well known in the art that in aromatic electrophilic substitution reactions, the aromatic ring would be more reactive if its electron density is increased. Electron donating substituents attached to the aromatic rings would make these rings more electron rich and thus make them more reactive. Such substituents are generally termed as +1 (inductively positive), +M (mesomeric) or +R (resonance) groups. Preferred electron donating substituents can be selected, but are not limited to, from ethers, alkyl, suitably substituted aryl and amino groups. Examples of presently preferred electron donating substituents are -OR, -OH,

-CH ₃ , -C ₂ H ₅ , -C ₃ H _7j -NR ₂ , -NHR, -NH ₂ or -NHCOR. R is typically an alkyl carbon chain with 1 to about 6 main chain carbon atoms and can be branched or straight chained. Examples of the substituent R include methyl, ethyl, propyl, isopropyl, and butyl, tertiary butyl, pentyl, isopentyl, hexyl and isomers thereof. Examples of such substituted aralkonic acids include 2-aminophenyl acetic acid, 3-aminophenyl acetic acid, 2-anilinophenyl acetic acid, 2-hydroxyphenyl acetic acid, 3-hydroxyphenyl acetic acid, 2-methoxyphenyl acetic acid, 3-methoxyphenyl acetic acid, 2,5-dihydroxyphenyl acetic acid, 2-aminophenyl propionic acid, 2,5-bis (trifluoromethyl) phenyl acetic acid, 3-aminophenyl propionic acid, 2-anilinophenyl propionic acid, 2-hydroxyphenyl propionic acid, 3-hydroxyphenyl proponic acid, 2-methoxyphenyl propionic acid or 3- methoxyphenyl propionic acid to new a few out of the numerous suitable acids. If free amino and hydroxyl groups are present as substituents in aralkanoic acids, these groups may suitably be protected before being subjected to polymerization. Suitable protective groups and respective reaction conditions are known to the person skilled in the art.

[0060] Groups like nitro, cyano, sulfonyl, haloalkyl and carbonyl are some of the groups which make the aromatic ring electron deficient and hence unreactive for the aromatic electrophilic substitution, as these groups are classified as -I (inductively negative), -M (mesomeric) or -R (resonance). In spite of their electron withdrawing nature these groups, however, can be presented on the aromatic ring or as substituents of other alkyl, aryl or amine groups which are present as substituents on the aromatic ring as long as the overall effect of all substituents is an electron donating effect and therefore support the polymerization reaction leading to the formation of the poly(arylalkyl ketone).

[0061] In some embodiments ar is an arylaliphatic moiety in which an aliphatic bridge connects two aromatic rings. Illustrative examples of such an arylaliphatic moiety are the formulas (I) - (IV)

In these formulas G is one of CH ₂ , O, S and NH. Each of the aromatic rings can be optionally substituted. In some embodiments ar is an arylaliphatic moiety in which an alicyclic bridge connects two aromatic rings. Illustrative examples of such an

Again, in these formulas G is one of CH ₂ , O, S and NH, and each of the aromatic rings can be optionally substituted. Further examples of suitable moieties ar are of the formul

In these moieties Y and Z are independently selected from the group consisting of -CH ₂ -, -CH-, O, S, and N. Again each of the aromatic rings can be optionally substituted.

[0062] In some embodiments of the invention the aromatic, arylaliphatic or arylalicyclic moiety "ar" can be taken to include aromatic subgroups, which may be designated ar'. The moiety ar may include 1 to 6, including 2, 3, 4 or 5 respective subgroups. Illustrative exam les of such subgroups are the following

In these moieties m is an integer from 1 to 6, such as from 1 to 4, including 1 or 2. Where monomers having more than one aromatic ring that is available for electrophilic substitution are used in forming a polymer used in the present invention (AB2 type) the polymer that is obtained upon polymerisation is typically non-linear branched. These types of non-linear polymers are commonly termed as hyperbranched polymers in the art. Suitable methods of forming polymers used in the present invention have been disclosed US patent application US7034187.

[0063] In case two or more aromatic subgroups are present in the aromatic, arylaliphatic or arylalicyclic moiety "ar", an oligomeric aromatic compound ar' _m is included in the monomeric units of the polymer in the invention. This oligomer can be a homo- or a heteropolymeric compound. The different aromatic subgroups may be present in succession as well as in alternating arrangement. An example of such a heteropolymeric moiety ar that is defined by different subgroups ar' _m is a moiety with alternating phenyl (Ph) and naphthyl (Np) residues which has the structure Ph-Np-Ph- Np-. Another example of an alternating arrangement is the residue Ph-Th-Ph-Th, if phenyl and thiophenyl (Th) are used as building blocks ar' _m for the moiety ar, which can be present in an aralkanoic acid such as Ph-Th-Ph-Th-CH ₂ -COOH or Ph-Th-Ph-Th- CH ₂ -CH ₂ -COOH. An example of a moiety ar defined by aromatic building blocks that are arranged in succession is Ph-Ph-Th-Th, or An-An-Ph-Ph, if anthracene (An) and phenyl are used. [0064] As noted above, the poly(arylalkyl ketone) used in a method according to the invention has monomer units of the general formula [-ar-(CX ₂ ) _n -C(0)-]. In this formula X is an electron donating group, including H, providing electron density to the aromatic ring of the aromatic, arylaliphatic or arylalicyclic moiety. Electron donating substituents attached to the aromatic rings would are known in the art as rendering these rings more electron rich, thereby also increasing their reactivity. Such substituents are generally termed as +1 (inductively positive), +M (mesomeric) or +R (resonance) groups. A respective electron donating substituent can be selected, but is not limited to, from an ether, an alkyl, as well as a suitably substituted aryl and amino group. Illustrative examples of electron donating substituents are -OR, -OH, -CH ₃ , -C ₂ H ₅ , -C ₃ H _7, -NR ₂ , - NHR, -NH ₂ or -NHCOR. R is typically an alkyl carbon chain with 1 to 6 main chain carbon atoms and can be branched or straight chained. Examples of the substituent R include methyl, ethyl, propyl, isopropyl, and butyl, tertiary butyl, pentyl, isopentyl, hexyl and isomers thereof.

[0065] A corresponding monomer unit may in some embodiments be 2- aminophenyl acetyl, 3-aminophenyl acetyl, 2-anilinophenyl acetyl, 2-hydroxyphenyl acetyl, 3-hydro yphenyl acetyl, 2-methoxyphenyl acetyl, 3 -methoxyphenyl acetyl, 2,5- dihydroxyphenyl acetyl, 2-aminophenyl propionic acid, 2,5-bis (trifluoromethyl) phenyl acetyl, 3-aminophenyl propionic acid, 2- anilino phenyl propionic acid, 2-hydroxyphenyl propionic acid, 3-hydroxyphenyl proponic acid, 2-methoxyphenyl propionic acid or 3- methoxyphenyl propionic acid to new a few out of the numerous suitable monomer units. The corresponding monomers for the formation of the polymer may be the aralkonic acids 2-aminophenyl acetic acid, 3-aminophenyl acetic acid, 2-anilinophenyl acetic acid, 2-hydroxyphenyl acetic acid, 3-hydroxyphenyl acetic acid, 2- methoxyphenyl acetic acid, 3 -methoxyphenyl acetic acid, 2,5-dihydroxyphenyl acetic acid, 2-aminophenyl propionic acid, 2,5-bis (trifluoromethyl) phenyl acetic acid, 3- aminophenyl propionic acid, 2-anilinophenyl propionic acid, 2-hydroxyphenyl propionic acid, 3-hydroxyphenyl proponic acid, 2-methoxyphenyl propionic acid or 3- methoxyphenyl propionic acid to name a few out of the numerous suitable acids. If free amino and hydro yl groups are present as substituents in aralkanoic acids, these groups may suitably be protected before being subjected to polymerization. Suitable protective groups and respective reaction conditions are known to the person skilled in the art.

[0066] X may for example be one of H, -OH, -OR, -NH2, -NHR, and -NR2. In groups -OR, -NR2 and -NHR the moiety R may be an aliphatic or an alicyclic group with a main chain of 1 to about 10 carbon atoms, such as 1 to about 8 carbon atoms or 1 to about 6 carbon atoms, including 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. As a few examples, R may be methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2- butenyl, 3-butenyl, n-pentyl, isopentyl, neopentyl, 3 -methyl-butyl, 2-pentenyl, 3-pente- nyl, 3-methyl-2-butenyl or tert-pentyl. X may also be an aliphatic or an alicyclic group.

[0067] In contrast thereto, groups like nitro, cyano, sulfonyl, haloalkyl and carbonyl are some of the groups which render the aromatic ring electron deficient and hence unreactive for the aromatic electrophilic substitution, as these groups are classified as -I (inductively negative), -M (mesomeric) or -R (resonance). In spite of their electron withdrawing nature these groups, however, can be included as substituents on the aromatic ring or as substituents of other alkyl, aryl or amine groups which are present as substituents on the aromatic ring as long as the overall effect of all substituents is an electron donating effect, thereby supporting the polymerization reaction leading to the formation of the polymer.

[0068] Degradation of matter can be reflected by a weight loss curve obtained in thermogravimetric analysis, as depicted in Fig. 4. The present inventors surprisingly found that poly(aralkyl ketone)s (PAK) disclosed in US7034187 yield char in high quantities upon heating as revealed by the thermogravimetric analysis (TGA) of the polymer (Fig. 4). As can be taken from the figure, the polymer has a high char yield, with 58.2 % residue being found at 800 °C. Fig. 5 (according to Ranganathan, T, et al. Macromolecules (2006) 39, 5974, and to Walters, RN, et al. J. Appl. Polym. Sci. (2003) 87, 548) shows the quantity of char formed in various aromatic polymers. A closer look at the table of Fig. 5 clearly indicates that even though PAK has aromatic/arylalipatic/ arylalicyclic as well as aliphatic units in its backbone, the extent to which char formation occurs is even greater than that of many of the polymers with fully aromatic backbones. A comparison of the TGA of PAK with an aromatic polymer such as polyimide also reveals that not only the char formed in the case of PAK is greater but also the char forming temperature is lower. In addition, thermal degradation occurs over a relatively broad temperature range (cf. Fig. 2). This effect is to be seen in the context of fire retardants developed to replace halogenated compounds, where the fire prevention occurs by the formation of char which acts as a blanket to prevent further spread of fire. Since organic compounds typically form volatiles and become flammable at about 300-400 °C, a means of flame protection and/or a flame retarding effect is/are required at such temperatures. Therefore, ideally, the char layer should be formed in this temperature range or below. This is not the case for polyimide or polystyrene (see Fig. 2), while char formation already occurs in the temperature range between 300 and 400 °C for a poly(aralkyl ketone) according to the invention (see e.g. Fig. 4). Broader thermal degradation further indicates char formation over the respective temperature range and thus the continued protection by char. In the case of other aromatic polymers, however, burnability of materials may have preceded the char formation thereby making the char formed redundant.

[0069] Further, no evolution of toxic gases is observed when a respective poly(aralkyl ketone) is exposed to fire. Nevertheless when used e.g. to form flame/fire protective matter or as an additive as a flame retardant it forms stable char. Preliminary results have also shown that the char formed in an intumescent coating according to the invention was denser and firmer than a char formed using conventional additives. Adding the poly(aralkyl ketone) as a flame retardant has further been found by the inventors not to have any plasticizing effect. Hence, when used as an additive, a PAK of the invention does not affect the properties of the plastic/fabric, in which it is used as an additive, accordingly. Likewise, when used in an intumescent coating the char formed is dense and firm.

[0070] Furthermore, a comparison of the TGA of a poly(arylalkyl ketone) of the invention with a phosphorus based flame retardant such as ammonium polyphosphate (APP) clearly indicates the transient nature of the char formed in the latter case (Fig. 6). The analysis of the volatiles emanating from a poly(arylalkyl ketone) also indicated that it is in fact water which is eliminated upon heating the polymer (Fig. 7). As shown in Figure 7, water begins to be eliminated above 100 °C and continues up to 500 °C. Above this temperature the curve shows a sharp drop.

[0071] Without wishing to be bound by theory the formation of high quantities of char in the case of PAK is thought to be due to its existence predominantly in the enol form as shown in Fig. 9. The process of char formation of a poly(arylalkyl ketone) according to the invention not only occurs at a lower temperature but also spontaneous, i.e. without the requirement of additional agents such as a catalyst. Accordingly it is, without being bound by theory, concluded that the heat caused by the fire is the catalyst for the liberation of water which leads to char formation. For all practical purposes, the char formation has to occur at a lower temperature preferably well before the organic materials begin to burn. In the case of a poly(arylalkyl ketone) of the invention, since it evolves water due to the action of heat caused by fire, the initially supplied heat will be taken up by the poly(arylalkyl ketone). Hence, the poly(arylalkyl ketone) not only forms a blanket against fire later but also forms a blanket against heat before, i.e. at an initial stage. In other words, the poly(arylalkyl ketone) acts as an insulating material against heat in the first instance, i.e. initially, before acting as flame retardant at a later stage. The char formation is expected to occur by reactions within the repeating unit, i.e. by an intramolecular reaction of the polymer chain. Therefore the uncertainties encountered in conventional intumenscent coatings are avoided by using a poly(arylalkyl ketone) according to the invention. Owing to the intramolecular nature and the high quantity of char formation, the amount of material required as flame retardant and intumescent additive is well below that of conventional additives.

[0072] Even if used in materials that per se have poor flame insulating properties and that release heat upon exposure to fire, the poly(arylalkyl ketones) of the invention are accordingly particularly useful as fire insulating additives and flame retardants since they reduce the heat release rate of matter that includes these poly(arylalkyl ketones). This effect is particularly advantageous since such matter releases less heat to neighbouring materials and diminishes fire propagation. As an illustrative example, if a fire is started in a warehouse where large quantities of materials are stored, the fire is prevented from getting out of control and can be extinguished much easier. The poly(arylalkyl ketones) of the invention are thus in one illustrative embodiment advantageously used for shipping pallets and shipping containers.

[0073] On a more general basis the poly(arylalkyl ketones) can be used whenever and wherever there are fire safety concerns. The poly(arylalkyl ketones) may for instance be used for automotive applications, such as for a fire shield for fuel tanks, car floors, bulk heads, wheel well covers or in other places in cars, trucks, boats, or airplanes to provide resistance to ignition or resistance to flame travel from the fire source to other areas. As a further example, applications in residential or commercial structures may help fire containment within each structure as well as slowing down the spread of fire from one structure to a neighbouring structure. Replacement of metal parts with such polymers that include the poly(arylalkyl ketones), in applications requiring fire integrity, can in addition lead to appreciable weight reduction.

[0074] Upon pyrolysis at a temperature in the range from about 300 °C to about 3000 °C, e.g. 600 °C to about 3000 °C carbonized material is formed from the poly(arylalkyl ketone) under inert atmosphere. The carbonized material has properties resembling those of graphite. The respective pyrolytic carbon material corresponds to other such pyro lytic carbon material in that it is an excellent planar thermal conductor. This material may be used as an adsorbent, as an electrode material, in forming a ceramic material, for forming carbon fibers, as a reinforcement material in forming a composite with a polymer, as a reinforcement material for matter of metal and as a black pigment. It may also be used in a coating of an orthopaedic implant or in a coating of a blood-contacting prosthesis. In the latter case it reduces the risk of thrombosis.

[0075] A poly (arylalkyl ketone) as defined above may be used to form a fire barrier or be applied on or to, embedded in or integrated with/in any solid material that is to be rendered flame resistant. In practice, the applicability of a polymer of the invention as an additive or as a coating will only be limited by the properties and the capability of matter to be protected to undergo a process, in particular without losing its integrity. As an illustrative example, a given matter with a consistency and absorptivity resembling that of natural stone will typically be treated with an intumescent coating as defined above - rather than e.g. be provided with an additive. It may be desired to select matter that is particularly at risk in case of fire, such as combustible matter. In some embodiments the poly (arylalkyl ketone) is applied to or included in fabric, plastic, wood and/or paper. The poly (arylalkyl ketone) may also be applied to or included in metal, glass, ceramic, concrete, composite building material such as breezeblock, tile or brickwork, china, or other vitreous ware. In some embodiments the solid matter comprises one of a fiber (which may be included in a woven or non-woven plurality of fibers), a film, a foam, a thread, a powder and a suspension. Where the solid matter is a foam, it may for instance be provided as a fine dust, i.e. as a powder or as a dispersion in a solvent, including water.

[0076] Applying the poly (arylalkyl ketone) to a substrate, i.e. solid matter, may include coating or impregnating the substrate, or printing. The substrate can, for instance be immersed into a solution or a composition that includes the poly (arylalkyl ketone). Where in a method or a use according to the invention matter is impregnated with a poly (arylalkyl ketone), this may for example be carried out as, or include carrying out, dip impregnation, vacuum impregnation and/or trickle impregnation. In the dip impregnation process, a substrate is dipped into the respective solution or composition for a preselected time interval, or pulled through the solution or composition. In a vacuum impregnation process, a substrate is placed into a closed container, vacuum is applied, whereafter the solution or composition can be flushed into the container. In a trickle impregnation process, the solution or composition can be trickled with e.g. a nozzle onto the rotating substrate. No curing in terms of a chemical reaction is required to finalize matter consisting of or including a poly(arylalkyl ketone), a coating that includes a poly(arylalkyl ketone) or a respective additive. If processed from solution or water based systems, in some embodiments adequate time may be given for the liquid portion i.e. water or solvent, to evaporate. Coating may be carried out using any process known in the art such as brushing, spraying, sputtering, sheet lamination or spin coating.

[0077] The poly(arylalkyl ketone) can thus serve as a flame retardant, a component of a flame-retardant composition, e.g. an at least essentially halogen- and phosphorus- free flame-retardant composition, an intumescent coating and a component of a coating composition, such as an at least essentially halogen- and phosphorus-free coating composition. Fig. 10 and Fig. 11 illustrate the potential of a polymer of the invention as a fire retardant and an intumescent coating in comparison to commercially available additives. In general intumescent additives are used in much higher dosages than fire retardants since the amount of char formed is proportional to the concentration of additives.

[0078] The present invention not only provides a flame retardant and flame retardant additive based on a poly(arylalkyl ketone) as a high char forming polymer, but also plastic material and fabric (typically as used in a textile). Any plastic material and fabric may be used for which the starting material is capable of integration a poly(arylalkyl ketone) as defined above. To name a few illustrative examples, polyvinyl chloride, polyester, polypropylene, polyethylene or polyurethane may include a corresponding poly(arylalkyl ketone). To the suitable organic polymer compound serving as a starting material for the formation of the plastic material or fabric, which may be synthetic, semi-synthetic or a naturally occurring polymer, the poly(arylalkyl ketone) may be admixed. Thereafter a standard technique for forming the respective plastic material or fabric such as molding and/or extruding may be employed. As an illustrative example, a plastic material that includes a flame retardant according to the invention may also be used in a fire barrier wrap for protecting electrical wires. A respective polymer may also be an epoxy resin, a phenolic resin, a urea resin, as well as e.g. a polyvinyl chloride, a polyethylene polymer, a polypropylene polymer, a polytetra- fluoroethylene, a polypropylene polymer or a polycyanurate based polymer.

[0079] The flame-retardant, smoke-suppressant, and heat-resistant properties of a plastic material, wood based material, fabric or other material according to this aspect of the invention may be further improved by the addition of inert additives such as fiberglass, including chopped fiberglass fibers, which can replace a portion of flammable components typically found in such products. In some embodiments the addition of inert additives such as fiberglass improves the physical and mechanical properties of matter such as plastic, including in the presence of heat.

[0080] Additional objects, advantages, and features of this invention will become apparent to those skilled in the art upon examination of the following examples thereof, which are not intended to be limiting. Thus, it should be understood that although the present invention is specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

[0081] In order that the invention may be readily understood and put into practical effect, particular embodiments will now be described by way of the following non- limiting examples.

EXAMPLES

Example 1: Preparation of Poly(araIkyl ketone) (PAK)

[0082] A 5L capacity Lara® glass reactor was charged with methane sulphonic acid (2 L) followed by phosphorus pentoxide (430 g, 1.5147 mol). The mixture was stirred by an overhead mechanical stirrer. Phenyl acetic acid (200 g, 1.47 mol) was then added followed by methane sulphonic acid (1 L). The reaction mixture was heated at 70°C with stirring under nitrogen atmosphere for 22 h. After cooling down, the reaction mixture was collected in a beaker and added slowly to large excess of ice cold water. The brown coloured solid precipitated was separated by filtration and washed with 10 wt% potassium carbonate solution followed by water and dried in a hot air oven. The dried solid was then subjected to Soxhlet extraction using acetone. The brown solid was then dried in oven to constant weight. Yield 165 g (95%).

[0083] IR (KBr) cm ^"1 : 3446 (b, v _0H of enol), 3060, 3029 (m, v _=CH ), 1759 (m, Vc=o of anhydride), 1670 (w, vc=o), 1635 (s, vc ₌ c of enol), 1601 (s, vc=c of aromatic backbone), 1495 (s), 1409 (s), 1374 (s), 1209 (s), 1194 (s), 1148 (s), 1109 (s), 1059 (s), 786 (s), 757 (s), 701 (s). [b - broad, m- medium, s - sharp, w - weak]. [0084] In the solid state ¹³ C-NMR analysis, the starting phenyl acetic acid showed signals at 39 ppm, 126.5-131.9 ppm and 179.6 ppm corresponding to the carbon nuclei of -CH ₂ -, aromatic carbon atoms of the phenyl group, ^H ₅ and -COOH respectively. The solid state ¹³ C-NMR analysis of the product showed very weak signals in the aliphatic region at 26.7 ppm and 37.27 ppm. A very strong aromatic signal centred at 126.38 ppm was also observed.

[0085] TGA (N ₂ atm, 10 °C/min): 5 % weight loss at 326 °C, 10 % weight loss at 389 °C, 20 % weight loss at 494 °C. Residue at 800°C was 62.32 %.

Example 2: Preparation of Poly(aralkyl ketone) (PAK) [0086] A 5 L capacity Lara ^® glass reactor was charged with methane sulphonic acid (2 L) followed by phosphorus pentoxide (430 g, 1.5147 mol). The mixture was stirred by an overhead mechanical stirrer. Phenyl acetic acid (200 g, 1.47 mol) was then added followed by methane sulphonic acid (1 L). The reaction mixture was heated at 70 °C with stirring under nitrogen atmosphere for 22 h. After cooling down, the reaction mixture was collected in a beaker and added slowly to large excess of ice cold water. The brown coloured solid precipitated was separated by filtration and washed with 10 wt% potassium carbonate solution followed by water and dried in a hot air oven. Yield 168 g (97 %).

[0087] IR (KBr) cm ^"1 : 3411 (b, v _0H of enol), 3057, 3027 (s, v _=CH ), 1761 (s, v _c =o of anhydride), 1710 (w, v _c =o of -COOH), 1680 (m, v _c =o), 1636 (s, v _c =c of enol), 1601 (s, v _c =c of aromatic backbone), 1495 (vs), 1409 (s), 1369 (s), 1221 (m), 1182 (s), 1148 (s), 1109 (s), 756 (s), 700 (vs). [b - broad, m - medium, s - sharp, vs - very sharp, w - weak].

[0088] TGA (N ₂ atm., 10 °C/min): 5% weight loss at 322 °C, 10% weight loss at 369 °C, 20% weight loss at 432 °C. Residue at 800°C was 57.98 %.

Example 3: Flame spread test by British Standard 476: Part 7

[0089] The BS 476 Part 7 test defines levels of irradiance to be used and determines the lateral spread of flame on the surface of a sample oriented in the vertical position. A specimen in form of an 885 mm long test panel is arranged in a holder with a vertical radiation panel and a pilot flame on one end. Based on the rate and extent of travel of a flame front across the test panel the surface spread of flame is classified. To achieve a class one classification the flame spread after 1.5 and 10 minutes must be less than 165 mm (details of the current version of the standard are published by the British Standards Institution and can be ordered from its website, under "Fire tests on building materials and structures", at http://shop.bsigroup.com).

[0090] A coating was formulated by doping of the additive of Example 1 as flame retardant at 6 wt%. The coating used was a water based nano-epoxy top coat available by the trade name Dr. Fixit Flame Shield (Pidilite Industries_Ltd., Mumbai, India), formulated with latex, inorganic pigments like Ti0 ₂ , fillers and (co)polymeric binders along with the flame retardant polymer (6 wt%). The coating contained water as a carrier and dispersing medium, allowing the coating process to be carried out in a manner resembling painting a wall. Thus, the coating flows before and during application like paint, and once applied it is allowed to dry. Hence, after applying the coating onto the surface water is completely evaporated, so that the coated surface is dry.

[0091] A rectangular cement board of the size 885 mm x 270 mm was coated with the composition. The board used was a fiber board made up of calcium silicate. The board as such is accordingly not combustible as it is made up of inorganic compounds but the coated surface is combustible. The combustible component is the organic polymers and other flammable materials used in the coating formulation. The test thereby allows an assessment of the properties of the coating without the need to take the combustibility properties of the substrate into account. The thickness and area bulk density of the sample were found to be approx. 4.8 mm and 6.8kg/m ² respectively. During the test, the coated surface is exposed to a pilot flame for 2 minutes (supra) and the surface catches fire during this exposure. A Bunsen burner was used for this purpose. The exposure to a red hot surface as a radiation panel (supra) serves in sustaining the flame. These details may available in the test manual as part of the test procedure).

[0092] In the comparative example a coating was used, which was a water based nano-epoxy top coat formulated with latex, inorganic pigments and binders along with inorganic polyphosphates and phosphate esters (9 wt%). The thickness and area bulk density of the sample were found to be approx. 4.9 mm and 7 kg/m respectively.

[0093] As mentioned above, a rectangular shaped cement board covered with this coating was subjected to British standard 476: Part 7: 1997. In the coating formulated with the flame retardant polymer of the invention, intense charring occurred when exposed to fire (Figure 8) and the surface did not burn. No smoke was detected in this test (ibid). Further, the extent of the flame spread was significantly smaller than in the comparative sample. In contrast thereto, in the case of coating formulated with inorganic and organo phosphates, the surface did burn because of the volatile nature of organophosphates and also due to the poor stability of char layer formed. According to the definitions specified in the test method, the sample coated with the PAK according to the invention was classified as Class One Surface Spread of Flame.

Example 4: BET adsorption studies using nitrogen as adsorbate on the char formed by pyrolysis

[0094] The polymer of Example 1 was subjected to pyrolysis under Argon gas. The following conditions were employed:

[0095] 1. Room temperature to 600 °C at a heating rate of 10 °C/min and then held at 600 °C for 30 minutes.

Char characteristics.

(i) . Surface area - Multipoint BET 50.8 m ² /g; Langmuir surface area 120 m ² /g.

(ii) . Total pore volume for pores with diameter less than 655.6A (at P P ₀ = 0.96973) 3.521 xl0 ^"2 cc/g.

(iii) . Average pore diameter 27.72-A.

[0096] 2. Room temperature to 800 °C at a heating rate of 10 °C/min and then held at 800 °C for 30 minutes.

Char characteristics.

(i). Surface area - Multipoint BET 409.4 m ² /g; Langmuir surface area 615.7 m ² /g.

(ii) . Total pore volume for pores with diameter less than 433.7 ^° A (at P/P ₀ = 0.95358)

2.435x10 ^" ' cc/g.

(iii) . Average pore diameter 23.8' ^° A.

[0097] A summary of the differences of the use of a poly(arylalkyl ketone)s in comparison to conventional compounds as flame retarding additives is given in Fig. 10.

[0098] One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. Further, it will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. The compositions, methods, procedures, treatments, molecules and specific compounds described herein are presently representative of preferred embodiments are exemplary and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention are defined by the scope of the claims. The listing or discussion of a previously published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[0099] The inventions illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising", "including," containing", etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied therein herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

[0100] The invention has been described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.

[0101] Other embodiments are within the following claims. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.