Self-cleaning composite material for producing molded kitchen and bathroom interior decoration items

Abstract

A self-cleaning composite material including the following composition: 50%-85% in weight of alumina trihydrate (ATH)-based mineral charges; 10%-30% of cross-linking polymer comprising polyester resin; photocatalytic Titanium Dioxide (TiO2) dispersed in the cross-linking polymer in a weight percentage from 0.05% to 5% with respect to the weight of the cross-linking polymer; compatibilizing agent for anchoring between the photocatalytic TiO2 and the cross-linking polymer, wherein the anchoring compatibilizing agent of the TiO2 is silane; and cross-linking monomers in order to obtain the reticulation of the cross-linking polymer by thermal or chemical polymerization.

Claims

1. A self-cleaning composite material comprising: 50-85% by weight of mineral charges; 10-30% by weight of polymer; photocatalytic titanium dioxide (TiO2); a compatibilizing agent for anchoring between the photocatalytic TiO2 and the polymer, wherein said anchoring compatibilizing agent of the photocatalytic TiO2 is silane; and cross-linking monomers that cross-link the polymer, wherein said mineral charges comprise alumina trihydrate (ATH), and said cross-linking polymer comprises polyester resin, wherein the photocatalytic titanium dioxide is dispersed in the cross-linked polymer in a weight percentage of 0.05%-5% with respect to a weight of the cross-linked polymer.

2. The self-cleaning composite material of claim 1, wherein said alumina trihydrate (ATH) has a grain size of 10-50 microns.

3. The self-cleaning composite material of claim 1, wherein methyl methacrylate (MMA) is added to said polyester resin in a weight percentage lower than 15% of the weight of the polyester resin and a methyl methacrylate (MMA) mixture.

4. The self-cleaning composite material of claim 1, wherein said silane is 3-(trimethoxysilyl) propyl methyl methacrylate and said silane is in a double quantity with respect to the photocatalytic TiO2.

5. The self-cleaning composite material of claim 1, further comprising: silanization catalysts.

6. The self-cleaning composite material of claim 1, wherein said photocatalytic titanium dioxide is in an anatase form and in a powder with a grain size lower than 300 nm.

7. The self-cleaning composite material of claim 1, wherein said crosslinking monomers comprise ethylene glycol dimethacrylate (EGDM), tetraethylene glycol methacrylate (TEGDM) and trimethylolpropane trimethacrylate (TMPTMA).

8. The self-cleaning composite material of claim 1, further comprising: fine particles of a silicate with a grain size lower than 0.1 mm, in a weight percentage between 2% and 15% with respect to the weight of the total composite material.

9. A production process for a self-cleaning composite material, the production process comprising: preparing a polyester resin in a quantity corresponding to 10%-30% of a final product weight; dispersing silane in the polyester resin; agitating the polyester resin and the silane; dispersing photocatalytic titanium dioxide (TiO2) in the polyester resin and the silane, in a weight percentage of 0.05%-5% with respect to a weight of the polyester resin; agitating the polyester resin, the silane and the titanium dioxide (TiO2); adding 50%-85% in weight of alumina trihydrate (ATH)-based mineral charges and cross-linking monomers to the polyester resin, the silane and the photocatylitic titanium dioxide in order to obtain a reticulation of the polyester resin; agitating the final mixture; and polymerizing the mixture in a mold.

10. The process of claim 9, wherein said silane is added in a double quantity with respect to the photocatalytic TiO2.

11. The process of claim 9, wherein the agitating of the polyester resin and the silane the agitating of the polyester resin, silane and titanium dioxide (TiO2) mixture are made with a screw agitator at a speed of between 900 rpm and 1800 rpm respectively for a time of 30 minutes and 2.5 hours before the step of adding.

12. The process of claim 9, wherein step of polymerizing in the mold is made at an initial temperature of 50 C. that increases gradually to 100 C. for a time of 8 hours.

13. The process of claim 9, wherein step of polymerizing is performed chemically, at room temperature, by one or more of TBPM (Tert-Butyl Peroxymaleate) in a percentage from 0.5% to 2.0%, Ca(OH)2 (calcium hydroxide) in a percentage from 0.5% to 1.0%, PETMP Pentaerythritol Tetra(3-mercaptopropionate) in a percentage from 0.1% to 1.0%.

Description

(1) Additional features of the invention will appear clearer from the following description, which refers to the merely illustrative, not limiting embodiments shown in the examples and in the attached Figures, wherein:

(2) FIG. 1 shows the anchoring of TiO.sub.2 to polyester resin;

(3) FIG. 2 is a chart that shows the trend of E of methylene blue, measured with colorimeter in three samples, after exposure to a Xenon lamp;

(4) FIG. 3 is a chart that shows the trend of E of eosin, measured with colorimeter, in three samples after exposure to a Xenon lamp; and

(5) FIG. 4 is a chart that shows the viscosity trend in three samples over time.

(6) The production process of the self-cleaning material provides for a first step in which the TiO.sub.2 active principle is added to polyester resin. This step provides for an exclusive anchoring process, by means of covalent bond, of the TiO.sub.2 active principle to the composite structure of the polyester resin, by means of a compatibilizing anchoring agent composed of the anchoring silanizing agent that determines the formation of the covalent bond between the photocatalytic TiO.sub.2 and the polyester resin.

(7) Silane is the cause of a silanization reaction that produces a covalent bond between TiO.sub.2 and the polyester substrate. Such a bond guarantees the anchoring of the TiO.sub.2 to the structure by means of a strong irreversible bond.

(8) Silane is perfectly dispersed in the polyester resin by means of agitation at 900 rpm for 10 minutes. Successively, the photocatalytic TiO.sub.2 is added to the polyester resin in order to obtain the best dispersion possible. Such a formulation is kept in dispersion with a screw agitator at a speed of 900 rpm for 2.5 hours. Then the speed is increased to 1800 rpm for 30 minutes, in such manner to guarantee a complete dispersion of the TiO.sub.2 in the polyester resin.

(9) The time necessary for the functionalization, that is to say for the silanization of the photocatalytic titanium, is approximately 3 hours. After such a reaction time the remaining components can be added.

(10) FIG. 1 shows the anchoring of TiO.sub.2 to the polyester resin.

(11) All the other components are added after anchoring the TiO.sub.2 to the silossanic function of the silane, starting from alumina trihydrate (ATH) mineral charges, followed by crosslinkers.

(12) Such a charged dispersion is kept homogeneously in agitation with a screw agitator at a speed of 900 rpm for 2.5 hours and at a speed of 1800 rpm for 30 minutes.

(13) The final dispersion is placed in a mold and polymerization is carried out either thermally or chemically at ambient temperature.

(14) Thermally, the material is heated starting from an ambient temperature of 25-30 C. for a time comprised between 30 and 40 minutes, then the temperature is increased with heating ramps up to 100 C. and cooled according to the type of dispersion and to the thermostatation system of the mold.

(15) Table 1 shows an example of a typical heating cycle for a strongly charged polyester dispersion.

(16) TABLE-US-00001 TABLE 1 TIME (min) Temperature 0 30 C. 0-60 65 C. For 8 hours 100 C.

(17) Chemically, using the same formulation/chemical composition, polymerization occurs by means of a series of suitable catalysts that start the reaction at ambient temperature. TBPM terbutyl peroxymaleate produced by Pergan PEROXAN PM-25 Ca(OH)2 THIOCURE PETMP Pentaerythritol tetra (3-mercaptopropionate) produced by BRUNO BOCK.

(18) The same aesthetic, mechanical and chemical results are achieved in the two different chemical and thermal polymerizations.

(19) The polyester resins functionalized with photocatalytic TiO.sub.2 showed excellent results in terms of degradation of various organic molecules, such as oleic acid and coloring agents, like eosin Y, methylene blue and red methyl. It was possible to obtain a charged polymeric material with self-cleaning surface by means of TiO.sub.2 mass dispersion in presence of the 3-(trimethoxysilyl)propyl methacrylate silossanic function.

(20) The silossanic group allows for anchoring TiO.sub.2 to the polyester resin structure and at the same time acts as disgregating agent; in this way, TiO.sub.2 is completely dispersed in the material both on the surface and in the mass.

(21) The alumina trihydrate (ATH) mineral charge particles with size lower than 0.1 mm provide a suitable homogeneity to the dispersion composition and favor a homogeneous surface upon molding.

(22) Advantageously, TiO.sub.2 is in anatase form and in powder, with a nanometric grain size lower than 300 nm.

(23) Advantageously, the polymeric part is only composed of polyester resin.

(24) A methacrylic monomer, such as methyl methacrylate (MMA), can be added to the polyester resin, in weight percentage lower than 15% compared to the weight of the polyester resin and MMA mixture.

(25) Preferably, the compatibilizing anchoring agent is silane, which is added to the mixture in a quantity equal to TiO.sub.2; silane can be added up to a double quantity compared to TiO.sub.2 in order to guarantee a complete disgregation of the photocatalyist (TiO.sub.2).

(26) If the compatibilizing agent is trimetoxisilane, silanization catalysts, isopropilamine (IPA) and methacrylic acid (AMA) are used in equal quantity.

(27) The peculiarity of the invention is represented by the dispersion of photocatalytic titanium dioxide (TiO.sub.2) inside the polyester resin and polyester with methyl methacrylate and mineral charge that is successively polymerized. For this reason, the following comparative studies and tests were made both on cross-linked resins and on resins containing the photocatalytic TiO.sub.2, both after adding inorganic material, such as alumina trihydrate (ATH) mineral charges that represent the majority of the final product.

(28) The photocatalytic degradation is exclusively carried out by the TiO.sub.2 that is found on the surface of the polymeric material. TiO.sub.2 is a heterogeneous catalyst that, when activated by light, can generate a series of oxigenated active species, such as O.sub.2..sup., .OH, and H.sub.2O.sub.2, which are suitable for degrading most organic agents. Therefore, TiO.sub.2 only acts as catalyst and does not participate in the degradation process directly.

(29) Based on the above considerations, the preparation of the material functionalized with TiO.sub.2 was carried out by mixing various organic components as indicated below:

(30) Organic Part methacrylic syrup: metylmethacrylate (MMA)/polymetylmethacrylate (PMMA) or polyester resin of POLYLITE 32166-16 REICHHOLD type or polyester resin of POLYLITE 32166-16 REICHHOLD type and methyl methacrylate MMA

(31) Cross-Linking Agents: dietylenglicoledimethacrilate (EGDM); tetraetylenglicoledimethacrilate (TEGDM); trimetylolpropane trimethacrylate (TMPTMA);

(32) Anchoring Molecule 3-metacriloxipropyltrimetoxisilane (SILANE);

(33) Silanization Catalysts isopropylamine (IPA); methacrylic acid (AMA);

(34) Releasing agents: stearic acid; Zn-stearate;

(35) Families of Mineral Charges Silicates (quartz, cristobalites, silicons, glass, glass full and/or empty enlightened glass microspheres), of either virgin or recovered type Aluminas (alumina trihydrate ATH, aluminum oxides) of either virgin or recovered type.

(36) Recovery can be of both internal and external type. It is of internal type by re-using ground sinks as GREEN recovery mineral charge or of external type by using mineral charges recovered from other industries, such as ceramic and mine industries instead of quartz, or ATH or other virgin mineral charges.

(37) Following are three examples of the samples used for various comparative tests with the prior art. The sample compositions are characterized by a different content of organic part, mineral charges and TiO.sub.2, but with the same amount of cross-linking agents and silane.

EXAMPLE 1 (PMMA/MMA (Syrup)+0.3% TiO2+Quartz) (Composition Described in WO2013/017651)

(38) The following components are mixed in a 1000 cc high-density polyethylene container using a screw agitator (speed from 900 to 1800 rpm): 305.00 grams of high-purity methyl methacrylate; 45 grams of methyl methacrylate polymer.

(39) The mixture was agitated until the complete dissolution of the PMMA polymetylmethacrylate polymer was obtained.

(40) Then the following components were added: 6 grams of silane DYNASYLAN MEMO 3 (Trimethoxysilyl)propyl methacrylate; 3 grams of TiO.sub.2 P-25 produced by DEGUSSA;

(41) Minimum mixing time is 2.5 hours and then the following components are added: 620.36 grams of quartz-type mineral charge with 0.1-0.6 mm size and white color 4.00, 3.00, 12.00 grams of cross-linking agents, respectively of EGDM-TEGDM-TMPTM; 0.60 grams of zinc stearate.

(42) Variable quantities of methacrylic acid (AMA) and isopropylamine (IPA) mixtures of 0.22 grams respectively were used as silanization catalysts.

(43) Preparation is made by mixing the aforementioned components in the following order; firstly, methyl methacrylate is mixed with polymetylmethacrylate (PMMA). Then cross-linking agents (EGDM, TEGDM, TMPTM) and Zn-stearate are added and the dispersion is agitated for at least 2.5 hours. In this way, only the organic part is mixed, then DYNASYLAN MEMO (3-(Trimethoxysilyl)propyl methacrylate) is added, followed by the addition of P-25 TiO.sub.2, AMA and IPA; in such way, it is guaranteed that the TiO.sub.2 interacts with the silossanic function before adding the mineral charge which is provided in excess with respect to TiO.sub.2; the TiOSi bond is sufficiently strong and this excludes competition phenomena between quartz and the silossanic function (Si(OCH.sub.3).sub.3), thus guaranteeing the anchoring of the photocatalytic TiO.sub.2 to the polymeric structure.

(44) Then, the mineral charge and the Zn-stearate are added and the dispersion is agitated or rolled for at least 6 hours, which is the time needed by the recovery mineral charge for bonding with the silossanic functions that are still free.

(45) Then, 0.5% of Perkadox 16 polymerization catalyst and 0.15% of stearic acid as releasing agent are added and the solution is agitated at 1800 rpm for 30 minutes.

(46) The final dispersion is placed in a mold and polymerization is made thermally: the material is heated starting from an ambient temperature of 25-30 C., which is gradually increased with heating ramps up to 100 C. and cooled, for an average time comprised between 20 and 40 minutes according to the type of dispersion and to the thermostatation time of the mold.

(47) Then, the mineral charge and the Zn-stearate are added and the dispersion is agitated or rolled for at least 6 hours, which is the time needed by the mineral charge for bonding with the silossanic functions that are still free.

(48) Then, 0.5% of Perkadox 16 polymerization catalyst and 0.15% of stearic acid as releasing agent are added and the solution is agitated at 1800 rpm for 30 minutes. Then the material is cast in the molds and polymerization is carried out according to the prior art.

EXAMPLE 2 (Polyester+0.3% TiO2+ATH) (Invention)

(49) The following components are mixed in a 1000 cc high-density polyethylene container using a screw agitator (900-1800 rpm): 420.00 grams of polyester POLYLITE 32166-16 REICHHOLD; 6 grams of silane DYNASYLAN MEMO 3(Trimethoxysilyl)propyl methacrylate;

(50) Then the following components are added: 3 grams of TiO.sub.2 P-25 produced by DEGUSSA;

(51) Minimum mixing time is 2.5 hours and then the following components are added: 559.2 grams of ATH (alumina trihydrate) mineral charge with size lower than 50 micron 4.00, 3.00, 12.00 grams of cross-linking agents, respectively of EGDM-TEGDM-TMPTM; 1.5 g of zinc stearate.

(52) Variable quantities of methacrylic acid and isopropylamine mixtures of approximately 0.06 and 0.07 grams respectively are used as silanization catalysts.

(53) Then, the mineral charge and the Zn-stearate are added and the dispersion is agitated or rolled for at least 6 hours, which is the time needed by the mineral charge for bonding with the silossanic functions that are still free.

(54) Then, 0.5% of Luperox MEKP (Methyl Ethyl Ketone peroxide) polymerization catalyst at 1.5% and 0.15% of stearic acid as releasing agent are added and the solution is agitated at 1800 rpm for 15 minutes. The material is cast in the molds and polymerization is carried out at constant temperature with water at 65 C. for 1 hour; successively, post-curing is made at 90 C. for 8 hours with polymerization according to Table 1.

EXAMPLE 3 (Polyester and MMA Solution+0.3% TiO2+ATH) (Invention)

(55) The following components are mixed in a 1000 cc high-density polyethylene container using a screw agitator (900-1800 rpm): 370.00 grams of POLYLITE 32166-16 REICHHOLD polyester; 60 grams of high-purity methyl methacrylate; 6 grams of silane DYNASYLAN MEMO 3(Trimethoxysilyl)propyl methacrylate; 3 grams of TiO.sub.2 P-25 produced by DEGUSSA;

(56) Minimum mixing time is 2.5 hours and then the following components are added: 549.92 grams of ATH (alumina trihydrate) mineral charge with size lower than 50 micron 2.25, 1.5, 6 grams of cross-linking agents, respectively of EGDM-TEGDM-TMPTM; 1.20 grams of zinc stearate.

(57) Variable quantities of methacrylic acid and isopropylamine mixtures of approximately 0.06 and 0.07 grams respectively are used as silanization catalysts.

(58) Then, the mineral charge and the Zn-stearate are added and the dispersion is agitated or rolled for at least 6 hours, which is the time needed by the mineral charge for bonding with the silossanic functions that are still free.

(59) Then, 0.5% of Luperox MEKP (Methyl Ethyl Ketone Peroxide) polymerization catalyst at 1.5% and 0.15% of stearic acid as releasing agent are added and the solution is agitated at 1800 rpm for 15 minutes. The material is then cast in the molds and polymerization is carried out at constant temperature with water at 65 C. for 1 hour; successively, post-curing is made at 90 C. for 8 hours with polymerization according to Table 1.

(60) As it can be seen, in all samples of examples 1, 2 and 3, Silane was added in double percentage than TiO.sub.2. The TiO.sub.2 dispersion and the catalyst disgregation is guaranteed both by the nanometric size of the TiO.sub.2 P-25 (average diameter is approx. 21 nm) and by the presence of the silossanic group provided in excess compared to the TiO.sub.2.

(61) It was possible to obtain a polymeric material with self-cleaning surface by means of mass dispersion of the TiO.sub.2 in the presence of the 3(Trimethoxysilyl)propyl methacrylate silossanic function. The silossanic group allows for anchoring the TiO.sub.2 to the structure of the polymeric material, and at the same time acts as disgregating agent.

EXAMPLE 4 (PMMA/MMA (Syrup)+0.3% TiO2+Quartz) (Composition Described in WO2013/017651) with Chemical Catalysis)

(62) The same formulation of EXAMPLE 1 is chemically polymerized with a series of suitable catalysts that start the reaction at ambient temperature. They are: TBPM terbutyl peroximaleate produced by Pergan PEROXAN PM-25 in percentage from 0.5% to 2.0%, namely 1% Ca(OH)2 in percentage from 0.5%-1.0%, namely 0.6% THIOCURE PETMP Pentaerythritol tetra (3-mercaptopropionate) produced by BRUNO BOCK in percentage from 0.1% to 1.0%, namely 0.2%

EXAMPLE 5 (Polyester and MMA Solution+0.3% TiO2+ATH) (Invention) with Chemical Catalysis)

(63) The same formulation of EXAMPLE 3 is chemically polymerized with a series of suitable catalysts that start the reaction at ambient temperature. The catalysts can be: TBPM terbutyl peroximaleate produced by Pergan PEROXAN PM-25 in percentage from 0.5% to 2.0%, namely 1% Ca(OH)2 in percentage from 0.5-1.0%, precisely 0.6% THIOCURE PETMP Pentaerythritol tetra (3-mercaptopropionate) produced by BRUNO BOCK in percentage from 0.1% to 1.0%, namely 0.2%
Comparative Tests on Polymerized-Composite Samples

(64) 1. TiO.sub.2 Photocatalytic Activity

(65) The photocatalytic activity was checked by assessing the decoloration of the following organic coloring agents, such as eosin and methylene blue, which simulate the natural coloring agents that are mostly used in cooking, such as wine, vinegar, strawberries, and other staining agents, which are placed on the composite surface.

(66) a) Self-cleaning of surfaces stained with eosin;

(67) b) Self-cleaning of surfaces stained with methylene blue;

(68) The self-cleaning of surfaces stained with eosin and methylene blue allows for assessing the degradation capacity of TiO.sub.2 against some coloring agents, such as eosin and methylene blue.

(69) The photocatalytic activity of the composite of examples 1 and 4, 2 and 3 and 5 (0.3% of photocatalytic TiO.sub.2 and mineral charges) was checked. The photocatalytic activity was checked by immersing the composite of examples 1 and 4, 2 and 3 and 5 (0.3% of photocatalytic TiO.sub.2) in a 0.0025 M solution of methylene blue and eosin Y and measuring the time needed to degrade said coloring agents. Degradation was made using a Xenon lamp (SolarBox 1500 and 25 mW/cm.sup.2, =280-400 nm, outdoor filter) and coloring was monitored with colorimetric measurements (Color I7 X-Rite). Measurements were made after 60, 90, 150, 210, and 270 minutes of exposure and the colorimetric variation was expressed in function of E.

(70) TABLE-US-00002 TABLE 2 E E E E E E METHYLENE time time time time time time BLUE 0 50 100 150 200 250 DEGRADATION min min min min min min EXAMPLE Syrup composite + 0 10 12 13 14 15 1 and 4 0.3% TiO2 + QUARTZ EXAMPLE Polyester 0 11 13 14 15 16 2 composite + 0.3% TiO2 + ATH EXAMPLE Polyester-MMA 0 12 13 15 16 17 3 and 5 composite + 0.3% 0.3% TiO2 + ATH

(71) Table 2 and FIG. 2 show the degradation of methylene blue of a composite sample from example 1 and 4, of a sample from example 2 and of a sample from example 3 and 5 (0.3% of photocatalytic TiO.sub.2 and mineral charges).

(72) TABLE-US-00003 TABLE 3 E E E E E E time time time time time time DEGRADATION 0 50 100 150 200 250 WITH EOSINE min min min min min min EXAMPLE Syrup composite + 0 15 20 22 25 28 1 and 4 0.3% TiO2 + QUARTZ EXAMPLE Polyester 0 13 15 20 22 25 2 composite + 0.3% TiO2 + ATH EXAMPLE Polyester-MMA 0 11 16 20 21 24 3 and 5 composite + 0.3% TiO2 +ATH

(73) Table 3 and FIG. 3 show the eosin degradation of a sample from example 1 and 4, of a sample from example 2 and of a sample from example 3 and 5 (0.3% of photocatalytic TiO.sub.2 and mineral charges).

(74) Based on the test results, coloring agents are degraded by TiO.sub.2; this is a very important result because it allows for defining the surface of material from examples 1 and 4, 2 and 3 and 5 as self-cleaning; moreover, it confirms that TiO.sub.2 had bonded to the structure of the polyester resin of examples 2 and 3 and 5, according to the invention, because TiO.sub.2 emerges to the surface as in example 1 on methacrylic syrup, according to the prior art.

(75) In all tests the materials that contained TiO.sub.2 showed a high dispersion and homogeneity of TiO.sub.2, without decantation phenomena, as shown by the chromatic coordinates, that is to say the color variation of the dispersion to assess the dispersion homogeneity in the tests of Table 4 below.

(76) TABLE-US-00004 TABLE 4 E EXAMPLE 1 Syrup composite + 0.3% TiO2 + 0.50 WO2013/017651 QUARTZ EXAMPLE 2 Polyester composite + 0.3% TiO2 + 0.60 Invention ATH EXAMPLE 3 Polyester-MMA composite + 0.3% 0.40 Invention TiO2 + ATH EXAMPLE 4 Syrup composite + 0.3% TiO2 + 0.50 WO2013/017651 QUARTZ chemical catalysis EXAMPLE 5 Polyester-MMA composite + 0.3% 0.40 Invention TiO2 + ATH chemical catalysis

(77) 2. Viscosity Variation with Silane Addition

(78) The viscosity of samples from examples 1, 2 and 3 with Silane and TiO2 in 1:2 ratio, at 0 time, at 60 minutes and at 120 minutes was measured in order to assess the chemical bond of Silane with the polyester resin.

(79) An evident variation of the resin viscosity is found after adding silane to a polyester resin or to a polyester resin and MMA with the addition of TiO.sub.2. Such a variation confirms the presence of direct interaction phenomena between TiO.sub.2 and silane. The measurement of TiO.sub.2 silanization time through the viscosity value of dispersions with different addition of silane gave the results shown in Table 5 and in FIG. 4 below.

(80) TABLE-US-00005 TABLE 5 Cps Cps Cps Viscosity Viscosity Viscosity time time VISCOSITY time 0 60 min 120 min EXAMPLE Syrup dispersion + 8,000 7,100 6,400 1 0.3% TiO2 + QUARTZ EXAMPLE Polyester dispersion + 4,000 3,500 3,300 2 0.3% TiO2 +ATH EXAMPLE Polyester dispersion 9,000 7,800 6,800 3 MMA + 0.3% TiO2 + ATH

(81) The viscosity values were measured at a temperature of approximately 20 C. As shown in Table 5 and FIG. 4, all the examples show a clear variation of viscosity when silane is added, this being an evident sign that a chemical bond is established. Data shows that the higher viscosity reduction is more evident after the first 60 minutes, this being a clear sign that the chemical bond is established within such a period of time.

(82) 3. Visible Cross-Linking on the Surface of the Finished Product

(83) In this test the finished products are sinks obtained from the dispersions of examples 1, 2 and 3. Cross-linking is visible with the naked eye in the three finished products because the sink surfaces show a very reticulated and very matt surface with a very high aesthetic appeal. Such a surface is very different from the surfaces that do not contain titanium dioxide bonded with silence, which are on the contrary very polished, with non-homogeneous opacity and poor cross-linking.

(84) 4. Hardness and Thermoformability

(85) Hardness and thermoformability tests were carried out on the samples of examples 1, 2, 3, 4 and 5, as respectively shown in Table 6 and 7 below. Hardness was measured in HRM.

(86) TABLE-US-00006 TABLE 6 HARDNESS HRM EXAMPLE 1 Syrup composite + 0.3% TiO2 + QUARTZ 105.00 EXAMPLE 2 Polyester composite + 0.3% TiO2 + ATH 90.00 EXAMPLE 3 Polyester-MMA composite + 0.3% TiO2 + 92.00 ATH EXAMPLE 4 Syrup composite + 0.3% TiO2 + QUARTZ 104.00 chemical catalysis EXAMPLE 5 Polyester-MMA composite + 0.3% TiO2 + 93.00 ATH chemical catalysis

(87) As shown in Table 6, the samples of examples 2 and 3 and 5 according to the invention have low hardness features compared to the sample of example 1 according to the prior art. For this reason, samples 2 and 3 and 5 are easy to work, whereas samples 1 and 4 are difficult to work.

(88) TABLE-US-00007 TABLE 7 Bending THERMOFORMABILITY degree EXAMPLE 1 and 4 Syrup composite + 0.3% 0 TiO2 + QUARTZ EXAMPLE 2 Polyester composite + 25 0.3% TiO2 + ATH EXAMPLE 3 and 5 Polyester-MMA 24 composite + 0.3% TiO2 + ATH

(89) As shown in Table 7, the samples of examples 2 and 3 and 5 according to the invention have a bending degree higher than 20, whereas the sample of example 1-4 has no bending degree. The bending degree is the angle that can be formed from a flat surface that is considered as angle 0.

(90) Therefore, samples 2a and 3 and 5 are thermoformable, whereas samples 1 and 4 are not thermoformable.

(91) Numerous variations and modifications can be made to the present embodiments of the invention, which are within the reach of an expert of the field, falling in any case within the scope of the invention as disclosed by the attached claims.