Compositions and Methods and Uses Relating Thereto

Abstract

A material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

Claims

1. A material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I) wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

2. A material of formula (I) according to claim 1 wherein M.sup.1 is caesium and M.sup.2 is selected from the group consisting of alkali metals, zinc and tin.

3. A material of formula (I) according to claim 1 wherein M.sup.1 is caesium; M.sup.2 is selected from sodium, potassium, tin or zinc; a is 0.22 to 0.4; b is 0.01 to 0.2; c is 1; d is 2.7 to 3; e is 0.05 to 0.25; n is 2; m is 1 and R is an unsubstituted alkyl or aryl group having 6 to 20 carbon atoms.

4. A method of preparing a material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I) wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group; the method comprising the steps of: (i) admixing: (a) a source of dopant species M.sup.1; (b) a source of tungsten; (ii) adding (c) an organophosphorus compound; and (iii) heating a mixture of (a) and (b) in a reducing atmosphere.

5. The method of claim 4, wherein (a) further includes a source of dopant species M.sup.2.

6. The method of claim 4, wherein the heating further includes heating (c) in the reducing atmosphere.

7. A composition comprising: the material of formula (I) of claim 1; and one or more additional components.

8. A composition according to claim 7 comprising a polymer having dispersed therein nanoparticles of a material of formula (I).

9. A method of preparing a composition according to claim 7, the method comprising combining a material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I) wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group; with the one or more further components.

10. A method according to claim 9 which involves directly admixing neat solid particles of a material of formula (I) with one or more further components.

11. An infrared absorbing material including the composition of claim 7.

12. A coating, powder coating, ink, or polymer containing the infrared absorbing material of claim 11.

13. A polymer film comprising particles of a material of formula (I) of claim 1.

14. A window that is at least partially covered by a composition comprising particles of a material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I) wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0140] FIG. 1 shows photographs of test plates used in Example 8, described below.

[0141] FIG. 2 shows the visible and infrared transmittance spectra of the plates used in Example 8.

[0142] FIG. 3 shows powder reflectance of the material of Example 4, described below.

[0143] FIG. 4 shows photographs of lasermarked plates of Example 8.

[0144] FIG. 5 shows the spectra for ink comprising material of the prior art.

[0145] FIG. 6 shows the spectra for ink comprising material according to an embodiment of the invention.

[0146] FIG. 7 shows the visible and infrared transmittance spectrum of a compound according to Example 7, described below.

[0147] It is believed that the present invention provides materials of formula (I) in which organophosphorus moieties are incorporated into the crystal structure of the tungsten oxide.

[0148] It is well known that tungsten oxides with a hexagonal or cubic or triclinic crystal structure are preferred for NIR absorbing material. In most cases the hexagonal structure seems to create the most efficient absorbing structure. The structure consists of tungsten-oxygen hexagonal lattice, which creates channels.

[0149] For stabilization of the structure the dopant metals are included. The dopant metals are enclosed in the channels. The ionic radius of the dopant metal is responsible for the degree of loading. For caesium as dopant metal the most widely described ratio between tungsten/caesium ratio is 3:1.

[0150] Without being bound by theory, based on solid state P-NMR evidence, it is believed that in the materials of formula (I), the organophosphorus moiety is incorporated onto and into the tungsten oxide lattice.

[0151] Incorporation of an organophosphorus compound onto or into the crystal lattice has also the effect that the particle size can be reduced and the degree of agglomeration is drastically reduced.

[0152] Compounds of formula (I) have been found to overcome problems relating dispersability and agglomeration that occur when using solid powders. Without being bound by theory, it is believed that the existence of a WOPR or WOPOR bond provides a more stable, readily deagglomeratable product. It can also believed that in the case where the oxidation state of phosphorus is +3, there is a beneficial effect on the oxidation stability of W.sup.5+.

[0153] The compounds of formula (I) therefore find considerable utility in a wide variety of applications.

[0154] According to a third aspect of the present invention there is provided a composition comprising a material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group; and one or more further components.

[0155] The composition of the third aspect comprises the material of formula (I) and one or more further components. The nature of the one or more further components will depend on the intended use of the material.

[0156] In some embodiments the composition of the third aspect comprises a polymer precursor composition. In such embodiments the composition suitably comprises a material of formula (I), and one or more monomers.

[0157] In such compositions the material of formula (I) is suitably present in an amount of from 0.001 to 10 wt %, preferably from 0.01 to 0.25 wt %.

[0158] In some preferred embodiments the polymer precursor composition does not comprise a solvent.

[0159] In some embodiments the polymer precursor composition further comprises a solvent.

[0160] Suitable solvents will depend on which monomers are present. Preferred solvents include water, alcohols (including glycols, ketones (for example methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK)), aromatic solvents (for example toluene) and aliphatic hydrocarbon solvents.

[0161] The nature of the monomer will depend on the desired polymer that will be prepared by the composition. In some preferred embodiments the monomer comprises an ester and the polymer produced is selected from polycarbonate, polyethyleneterephthalate, polybutylenterephthalate, and acrylate or methacrylate polymers or copolymers.

[0162] Other suitable monomers include vinyl and vinyl derived monomers, for example vinyl butyral.

[0163] Such polymer precursor compositions may comprise one or more further optional components. These are suitably selected from initiators, dispersants, stabilisers, UV-stabilisers, catalysts, flame retardants and other functional materials.

[0164] The material of formula (I) is suitably included in the composition of the third aspect, for example a polymer precursor composition as nanoparticles. Thus the third aspect of the present invention preferably provides a composition comprising nanoparticles of a material of formula (I) and one or more further components.

[0165] In some embodiments the composition of the third aspect may comprise a polymer. Thus the present invention may further provide a polymer having dispersed therein particles of a material of formula (I). Suitably the invention provides a polymer having dispersed therein nanoparticles of a material of formula (I).

[0166] A particular advantage of the material of the present invention is that it will suitably disperse into nanoparticles by regular production processes. No extra formulated dispersions, masterbatches or other intermediates are necessary to achieve a high performing NIR absorbing effect.

[0167] According to a fourth aspect of the present invention there is provided a method of preparing a composition of the third aspect the method comprising combining a material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group; with one or more further components.

[0168] In the method of the fourth aspect the material of formula (I) may be directly admixed in neat solid form with the one or more further components. The material of formula (I) can, for example, be directly mixed into a polymer precursor composition without the need for a diluent or carrier. Suitably nanoparticles can be directly incorporated into a composition.

[0169] Thus the fourth aspect of the present invention may involve directly admixing solid nanoparticles of a material of formula (I) with one or more further components.

[0170] The method of the present invention may further provide a method of preparing a polymer having dispersed therein particles, preferably nanoparticles, of a material of formula (I).

[0171] In some embodiments the method may comprise admixing particles, preferably nanoparticles, of a material of formula (I) with a polymer precursor composition comprising one or more monomers and then polymerising the monomers.

[0172] In such embodiments polymerisation may, for example, be carried out by condensation reactions or by UV induced polymerisation. The selection of an appropriate technique depending on the monomers involved will be within the competence of the skilled person.

[0173] In some embodiments the material of formula (I) may be mixed directly with polymers in an extrusion machine to make a masterbatch. In some embodiments the material of formula (I) may be mixed with the polymer to be used for injection moulding process to directly produce a transparent sheet, film, plate or other workpiece. Suitably no further treatment or particle size reduction processes are necessary.

[0174] A particular advantage of the present invention compared with processes of the prior art is that materials of the prior art have to be added to a polymer melt or monomer containing polymer precursor composition in the form of a paste or dispersion. This is not necessary in the case of the present invention in which the material of formula (I) can be directly added in particulate form and is self dispersing within a polymer film.

[0175] Thus the present invention may provide a method of preparing a polymer film having dispersed therein particles (especially nanoparticles) of a material of formula (I), the method comprising directly adding solid particles (especially nanoparticles) of a material of formula (I) into a polymer or polymer precursor composition. Suitably the particles (especially nanoparticles) of a material of formula (I) are not mixed with any other components (such as a diluent or carrier) prior to admixture with the polymer or polymer precursor composition.

[0176] According to a fifth aspect of the present invention there is provided the use of a material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group; as an infrared absorbing material.

[0177] The fifth aspect of the present invention relates to the use of the material of formula (I) to absorb infrared radiation. Preferably the use relates to the absorption in the near infrared region. Preferably the material absorbs light of at least one wavelength in the region from 780 nm to 2500 nm.

[0178] Preferably the material strongly absorbs light in the region from 780 nm to 2500 nm. Preferably the material transmits light in the region from 400 to 780 nm.

[0179] According to the fifth aspect the material of formula (I) can be used to absorb infrared radiation in a wide variety of applications.

[0180] In one embodiment the material of formula (I) may be used in films for protection against solar radiation for domestic windows or automotive glazing.

[0181] The material of formula (I) may be used in coatings, powder coatings, inks and in polymers for laser marking.

[0182] In one embodiment the material of formula (I) can be used as a spectral selective taggant for security printing and for anti-counterfeiting measures.

[0183] The material of formula (I) may be used in injection moulded parts.

[0184] In some preferred embodiments the fifth aspect involves the use of the material of formula (I) as an infrared absorbing material in a polymer film, especially a polymer film on a window.

[0185] According to a sixth aspect of the present invention there is provided a polymer film comprising particles of a material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

[0186] Suitably the sixth aspect of the present invention provides a polymer film having dispersed therein nanoparticles of a material of formula (I).

[0187] Preferably the polymer film absorbs infrared radiation and transmits visible radiation.

[0188] According to a seventh aspect of the present invention there is provided a window that is at least partially covered by a composition comprising particles of a material of formula (I)

M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e(I)

wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

[0189] In one embodiment the material of formula (I) is present in a film on the surface of the window.

[0190] In one embodiment the material of formula (I) is present in an organic or sol-gel coating on the surface of the window.

[0191] In another embodiment the material of formula (I) is present in a polymer film sandwiched between two glass panes. Suitably the window may be used as an automotive front window or as security glass.

[0192] The invention may further provide a building or a vehicle comprising a window of the seventh aspect.

[0193] Any feature of any aspect of the present invention may be combined with any feature of any other aspect of the invention as appropriate. In particular the material of formula (I) in the second, third, fourth, fifth, sixth, seventh and further aspects is as defined in relation to the first aspect.

[0194] The invention will now be further described with reference to the following non-limiting examples.

EXAMPLE 1

[0195] A clean reactor is filled with 100 kg DI-water and 18 kg caesium carbonate are dissolved with stirring. After the dissolution 82 kg of ammonium metatungstate are added with stirring at room temperature. Finally 45 kg of diphenylphosphate are added with stirring. Stirring is continued for 3 hours. After 3 hours the solution has turned turbid and the resulting slurry is dried with a spray drier. The resulting powder is transferred into saggars and is heated in an electric kiln under a nitrogen/hydrogen atmosphere at 600 C. for 2 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0196] The resulting dispersion is spray dried again and results in 86 kg of blue powder.

EXAMPLE 2

[0197] A clean reactor is filled with 100 kg DI-water and 18 kg caesium carbonate are dissolved with stirring. After the dissolution 82 kg of ammoniummetatungstate are added with stirring at room temperature. Finally 22 kg of phenylphosphonic acid are added with stirring. Stirring is continued for 3 hours. After 3 hours the solution has turned turbid and the resulting slurry is dried with a spray drier. The resulting powder is transferred into saggars and is heated in an electric kiln under a nitrogen/hydrogen atmosphere at 600 C. for 2 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0198] The resulting dispersion is spray dried again and results in 80 kg of blue powder.

EXAMPLE 3

[0199] A clean reactor is filled with 100 kg DI-water and 18 kg caesium carbonate are dissolved with stirring. After the dissolution 82 kg of ammoniummetatungstate are added with stirring at room temperature. Finally 35 kg of methylphosphonic acid dimethylester, dissolved in methanol are added with stirring. Stirring is continued for 3 hours. After 3 hours the solution has turned turbid and the resulting slurry is dried with a spray drier. The resulting powder is transferred into saggars and is heated in an electric kiln under a nitrogen/hydrogen atmosphere at 600 C. for 2 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0200] The resulting dispersion is spray dried again and results in 80 kg of blue powder.

EXAMPLE 4

[0201] A clean reactor is filled with 100 kg DI-water and 18 kg caesium carbonate are dissolved with stirring. After the dissolution 82 kg of ammonium metatungstate are added with stirring at room temperature. Finally 30 kg of 85% octylphosphonic acid dissolved in an water/ethanol mixture are added with stirring. Stirring is continued for 3 hours. After 3 hours the solution has turned turbid and the resulting slurry is dried with a spray drier. The resulting powder is transferred into saggars and is heated in an electric kiln under a nitrogen/hydrogen atmosphere at 600 C. for 2 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0202] The resulting dispersion is spray dried again and results in 85 kg of blue powder.

EXAMPLE 5

[0203] A clean reactor is filled with 150 kg DI-water and 82 kg of tungstic acid are added with stirring at room temperature. 22 kg of caesium carbonate are added with stirring. Stirring is continued for 3 hours at elevated temperatures of 80 C. The turbid dispersion is filtered and the filter cake is dried at 105 C. for 16 hours. After cooling to room temperature the yellow orange powder is dispersed in water again and 26 kg of phenylphosphonic acid are added and the mixture is continued to be stirred another 5 hours. The dispersion is filtered again, the filter cake dried again at 105 C. for 16 hours. The dry filter cake is crushed and heated in an electric kiln under a nitrogen/hydrogen atmosphere at 500 C. for 4 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0204] The resulting dispersion is spray dried and results in 98 kg of blue powder.

EXAMPLE 6

[0205] A clean reactor is filled with 150 kg DI-water and 82 kg of tungstic acid are added with stirring at room temperature. 22 kg of caesium hydroxide are added with stirring. Stirring is continued for 3 hours at elevated temperatures of 80 C. The turbid dispersion is filtered and the filter cake is dried at 105 C. for 16 hours. After cooling to room temperature the yellow orange powder is dispersed in water again and 30 kg of octylphosphonic acid in a water/ethanol mix are added and the mixture is continued to be stirred another 5 hours. The dispersion is filtered again, the filter cake dried again at 105 C. for 16 hours. The dry filter cake is crushed and heated in an electric kiln under a nitrogen/hydrogen atmosphere at 500 C. for 4 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0206] The resulting dispersion is spray dried and results in 98 kg of blue powder.

EXAMPLE 7

[0207] A clean reactor is filled with 150 kg DI-water and 82 kg of tungstic acid are added with stirring at room temperature. 22 kg of caesium hydroxide are added with stirring. Stirring is continued for 3 hours at elevated temperatures of 80 C. The turbid dispersion is filtered and the filter cake is dried at 105 C. for 16 hours. After cooling to room temperature the yellow orange powder is dispersed in water again and 54 kg of distearylphosphate in ethanol are added and the mixture is continued to be stirred another 5 hours. The dispersion is filtered again, the filter cake dried again at 105 C. for 16 hours. The dry filter cake is crushed and heated in an electric kiln under a nitrogen/hydrogen atmosphere at 500 C. for 4 hours. The resulting deep blue powder is dispersed in 200 l of DI water and ball milled until a surface area of at least 20 m.sup.2/gr is reached.

[0208] The resulting dispersion is spray dried and results in 98 kg of blue powder.

EXAMPLE 8

[0209] The inventive organophosphorus tungsten oxide of example 4 and a regular caesium tungstate powder compound were each mixed with polycarbonate in a dry blender and test plates were injection moulded under usual conditions. The level of each tungsten compound was 0.05 wt % in the polymer. No other additives were added.

[0210] A photograph of the test plates is provided in FIG. 1. The untreated test plates (A) were colourless. The visual inspection of the test plates showed that the test plates made with the regular caesium tungstate powder (B) were largely colourless, containing little black spots of undispersed material. The test plates made with the inventive tungsten composite material of example 4 (C) were a light green colour.

EXAMPLE 9

[0211] The visible and infrared transmittance spectra of the polycarbonate plates of example 8 were recorded. The results are shown in FIG. 2. Trace A is for a standard plate; trace B is for the plate with regular CWO; and trace C is for the plate having dispersed therein the material of example 4. The NIR analysis shows a very good result of the material of the invention: high transparency in the visible range, but much higher absorption in the 750-1200 nm range when compared with the non inventive CWO. FIG. 3 clearly shows that all plates transmit visible light at reasonable levels, but only the plate comprising the material of example 4 has a high absorption of infrared light.

EXAMPLE 10

[0212] The powder reflectance of the material of example 4 was recorded and is shown in FIG. 3. This spectrum shows that there is very little reflection in the range of 900-1800 nm, which means that there is a high absorption since there is no transmission in a powder sample.

EXAMPLE 11

[0213] The test plates generated in Example 8 were Lasermarked with a 1064 nm Laser and analysed. Pictures of the lasermarked plates are shown in FIG. 4. FIG. B1 shows the lasermarked plates with conventional CWO and FIG. B2 shows the Lasermarked plates of the inventive material of example 4.

[0214] The Lasermarking was done by exposing the test plates by a variation of the Laser Frequency versus the Line Displacement speed. The plates with the conventional CWO showed inhomogenous product distribution visible by the black spots. Due to the insufficient distribution only reasonable Laser Marking results were achieved with low line displacement speeds. At higher speeds no good results were obtained even at 1% content.

[0215] Plates containing the inventive material did not show any black spots indicating poor product distribution and showed better Laserresponse at a higher range of frequencies and line displacement speeds, which is visible by the increased number of coloured test field markings on the plates.

[0216] These results demonstrate that the organophosphorus modified tungsten oxide of the invention shows a higher degree of dispersion in the polymer than the CWO of the prior art.

EXAMPLE 12

[0217] As a further test the organophosphorus tungsten oxide compound of example 4 was incorporated into a printing ink and the effect on the infrared ray absorption tested.

[0218] Again state of the art CWO powder and the inventive organophosphorus tungsten oxide compound were blended at different levels into a non absorbing white base ink with the help of a speedmixer. The ready to use inks were applied via an orange proofer onto paper and polymer films.

[0219] The prints were dried and spectroscopically analysed. FIG. 5 shows the spectra for the ink comprising the material of the prior art. FIG. 6 shows the spectra for the ink comprising the inventive material.

[0220] It can be clearly seen that the organophosphorus tungsten oxide compound has a higher NIR absorption capability than the state of the art CWO powder. For example at 900 nm 5% CWO in the printing ink resulted in an absorption of 60%, whereas the same amount of organophosphorus tungsten composite resulted in a 75% absorption rate. At lower concentration rates the increase in NIR absorption is even bigger.

[0221] The spectra confirm that the organophosphorus tungsten oxide compound has a much better dispersability in the films and lead to a higher NIR absorption compared to state of the art materials.

EXAMPLE 13

[0222] The organophosphorus tungsten oxide compound of example 7 was dispersed in an organic aliphatic solvent at a concentration of 1 wt %. The visible and infrared transmittance spectrum of this dispersion is shown in FIG. 7.