Culinary utensil provided with a hybrid coating and process for producing such a utensil

Abstract

Provided is a utensil including a support having two opposite faces, at least one of which is provided with a sol-gel coating including at least one sol-gel layer that is present in the form of a continuous film of a sol-gel material including a matrix of at least one metal polyalkoxylate. Said utensil additionally includes a hybrid sol-gel coating including at least one screen-printed sol-gel layer completely or partially covering said sol-gel coating, said first hybrid sol-gel layer consisting of a hybrid sol-gel material including a matrix formed from a first hybrid sol-gel composition including at least one silicone resin and at least one silane and/or at least one metal alkoxide. Also provided is a process for producing such a utensil.

Claims

1. Method for producing a utensil said method comprising the following steps: a) providing a metallic support having at least two opposite surfaces; b) preparing a sol-gel composition comprising b1) the preparation of an aqueous sol-gel composition consisting of at least one metal alkoxide sol-gel precursor, b2) the hydrolysis of said sol-gel precursor in the presence of water and an acid or base catalyst, and finally b3) a condensation reaction resulting in the formation of an alcohol to produce the sol-gel composition; c) preparing a hybrid sol-gel composition comprising c1) the preparation of a mixture comprising, in a solvent medium, at least one silicone resin and at least one silane and/or at least one metal alkoxide, in which the solvent medium comprises at least one light organic solvent used as a diluent and at least one heavy organic solvent used as a humectant, wherein the light solvent has a boiling point of less than or equal to 150 C., and the heavy solvent has a molecular mass of greater than or equal to 100 g.Math.mol.sup.1 and a boiling point of greater than or equal to 150 C., and c2) a condensation reaction to produce the hybrid sol-gel composition; d) applying onto at least one of the support surfaces of at least one layer of the sol-gel composition resulting from step b) to create a sol-gel coating consisting of at least one sol-gel layer in the form of a continuous film; e) applying by partial or continuous serigraphy onto said coating of at least one layer of the hybrid sol-gel composition resulting from step c) to form an initial hybrid serigraphic sol-gel layer; and finally f) heating the applied coatings of steps d) and e) at a temperature between 150 C. and 350 C. wherein the hybrid sol-gel composition comprises from 40 to 70% by weight of the silicone resin based on the total weight of the hybrid sol-gel composition.

2. Method as in claim 1, in which the silane and/or metal alkoxide are pre-hydrolyzed.

3. Method as in claim 1, that further includes a step c) of adjusting a viscosity of the hybrid sol-gel composition to a value ranging from 0.2 Pa.Math.s to 5 Pa.Math.s, immediately following step c).

4. Method as in claim 3, wherein the step c) is carried out by the addition of a cellulose, whether modified or not.

5. Method as in claim 1, that further includes, immediately following step c) a step one of adding one or both of a pigment load and a reinforcing load to the hybrid sol-gel composition.

Description

BRIEF DESCRIPTION OF THE INVENTION

(1) Other advantages and particularities of the present invention will result from the following description, provided by way of example and therefore non-limiting, and referencing the examples in the annexed corresponding figures:

(2) FIG. 1 is a schematic cross-sectional view of a culinary utensil according to one embodiment of prior art;

(3) FIG. 2 is a schematic cross-sectional view of a culinary utensil according to another embodiment of prior art;

(4) FIG. 3 is a schematic cross-sectional view of a culinary utensil consistent with the present invention according to a first embodiment variant;

(5) FIG. 4 is a schematic cross-sectional view of a culinary utensil consistent with the present invention according to a second embodiment variant; and

(6) FIG. 5 is a schematic cross-sectional view of a culinary utensil consistent with the present invention according to a third embodiment variant.

DETAILED DESCRIPTION OF THE INVENTION

(7) The identical elements represented in FIGS. 1 and 2, and in FIGS. 3 through 5 respectively are identified by the same reference numbers.

(8) FIG. 1 (corresponding to the conditions of Comparative Example 3) is a cross-sectional view of a culinary utensil (110) according to one embodiment of prior art. Said culinary utensil (110) consists of an aluminum support (120) with two opposite surfaces (121) (interior surface) and (122) (exterior surface). The interior surface (121) is coated with an anti-adhesive coating (160), for example a coating made of fluorocarbon resin, enamel or a sol-gel material.

(9) The exterior surface (122) is covered with a first sol-gel coating (130) comprising a sol-gel layer (131) in the form of a continuous film of a sol-gel material comprising a matrix of at least one metal polyalkoxylate. Then, the first sol-gel coating (130) is covered by a second sol-gel coating (140) comprising a sol-gel layer (141) in accordance with the instructions provided in Example 13 of patent document U.S. Pat. No. 6,863,923.

(10) FIG. 2 (corresponding to the conditions of Comparative Example 4) is a cross-sectional view of a culinary utensil (110) according to a second embodiment of prior art. Said culinary utensil (110) consists of an aluminum support (120) with two opposite surfaces (121) (interior surface) and (122) (exterior surface). The interior surface (121) is coated with an anti-adhesive coating (160), for example a coating made of fluorocarbon resin, enamel or a sol-gel material.

(11) The exterior surface (122) is covered with a first sol-gel coating (130) comprising a sol-gel layer (131) in the form of a continuous film of a sol-gel material comprising a matrix of at least one metal polyalkoxylate. Then, the first sol-gel coating (130) is covered, using serigraphy, by a second sol-gel coating (140) comprising a sol-gel layer (141) in accordance with the instructions provided in patent document FR 2973390 that incorporates stainless steel beads (151, 152), a portion of which (152) protrude beyond the surface of the second sol-gel coating (140).

(12) The utensil illustrated in the annexed FIG. 3 is a culinary utensil 1 according to a first embodiment of the invention. The culinary utensil (1) illustrated in FIG. 3 corresponds to the conditions in examples 2 and 7.

(13) This culinary utensil (1) consists of an aluminum support (2) with two opposite surfaces (21) (interior surface) and (22) (exterior surface). The interior surface (21) is coated with an anti-adhesive coating (6), for example a coating made of fluorocarbon resin, enamel or a sol-gel material.

(14) The exterior surface (22) is covered with a sol-gel coating (3) comprising a sol-gel layer (31) in the form of a continuous film of a sol-gel material comprising a matrix of at least one metal polyalkoxylate. Finally, the sol-gel coating (3) is covered, with serigraphy, by a hybrid sol-gel coating (4) comprising a hybrid sol-gel layer (41) according to the present invention.

(15) The utensil illustrated in the annexed FIG. 4 is a culinary utensil (1) according to a second embodiment of the invention. The culinary utensil (1) illustrated in FIG. 3 corresponds to the conditions in examples 3, 5, 6, and 8 through 10.

(16) In the embodiment illustrated in FIG. 4, the hybrid sol-gel layer (41) of the hybrid sol-gel coating (4) comprises metal beads (51, 52) of which a portion (52) protrude beyond the surface of this hybrid sol-gel layer (41).

(17) The utensil illustrated in the annexed FIG. 5 is a culinary utensil (1) according to a third embodiment of the invention.

(18) In the embodiment illustrated in FIG. 5, the hybrid sol-gel coating (4) comprises two hybrid sol-gel layers (41, 42). The first hybrid sol-gel layer (41) is applied continuously with serigraphy onto the sol-gel coating (3). The second hybrid sol-gel layer (42) is applied discontinuously with serigraphy onto the first hybrid sol-gel layer (41). These two hybrid sol-gel layers (41, 42) comprise metal beads (51, 52, 53, 54) of which a portion (52, 54) protrude beyond the surface of the hybrid sol-gel layers, (41, 42) respectively.

EXAMPLES

(19) In these examples, except as indicated, all percentages and proportions are expressed by weight.

(20) Tests

(21) Flame Resistance:

(22) The coatings prepared in the following examples were exposed to the flame of a Bunsen burner for 20 seconds, then quench cooled in cold water. Following the flaming, the general appearance of each coating was assessed. Particular note was taken of any traces of oxidation (typically white/brown) or carbonization (typically black).

(23) Adhesion Test (Based on the Test in Standard EN 10209):

(24) The Erichsen test standard EN 10209 related to enameling was applied to sol-gel coatings prepared in the examples below. An ogive propelled by potential energy is used to strike the surface of each coating. Following the test, the residual adhesion of each coating to its metal support was evaluated.

(25) Abrasion Test (Based on the Test in Standard NFD 21-511):

(26) The abrasion resistance of the sol-gel type coatings prepared in the following examples was assessed by subjecting each coating to the action of a green SCOTCH BRITE or similar scouring pad. The abrasion resistance of each coating was qualitatively estimated with respect to the number of times the scouring pad had to be passed across the surface to create the first scratch (meaning the metal material forming the support could be seen).

(27) Scratch Test with Glass-Ceramic Cooktop:

(28) This test is designed to characterize the non-deterioration of glass-ceramic cooktops. It makes it possible to verify that a pan will not scratch the cooktop (test conducted on a cold cooktop). This test is intended for culinary utensils to be used with glass-ceramic and induction surfaces. The equipment used includes a pan, a clean and unscratched glass-ceramic cooktop, and a 100 gram weight.

(29) The 100 g weight is placed in the center of the pan, while the pan is positioned on the glass-ceramic cooktop. The pan is then moved horizontally over the glass-ceramic cooktop from A to B to C (see figure above) for 10 cycles.

(30) The condition of the glass-ceramic cooktop is then assessed and the presence of any scratches noted where applicable.

(31) Gloss (DIN EN ISO 2813)

(32) Use of a gloss meter (for example, the BYK Gardner Micro tri gloss) that is applied to the surface of an article and that emits a flash of light at a 60 angle (other angles possible, 20 and 85) to define surface reflection. Based on a scale of 100 GU (=gloss units measured against a black glass polished to the standard refractive index) where the resulting measurement is proportional to the refractive index of the surface (thus a measurement >100 GU is possible).

Examples Produced (Compositions and Experimental Conditions)

Example 1

Preparation of a Sol-Gel Coating on a Support

(33) A sol-gel composition SG1 of metal alkoxide precursors was prepared according to the composition specified below in Table 1.

(34) This composition SG1 was applied by spraying onto the aluminum supports to form, on each, a sol-gel coating.

(35) TABLE-US-00001 TABLE 1 Mass fraction Components (%) Sol-gel precursor with the 80 to 97% general formula M.sub.2(OR.sub.2).sub.(n1)R.sub.2 Sol-gel precursor with the 0 to 20% general formula M.sub.3(OR.sub.3).sub.(n2)R.sub.3.sub.2 Acid or basic catalyst 0.1 to 5% Water 1 to 10% Chelating agent (for example, an alcohol) 0 to 10%

Example 2

Hybrid Sol-Gel Composition According to the Invention, with Silanes but No Reinforcing Beads

(36) A hybrid sol-gel composition SGH1 according to the invention, containing a silicone resin and a silane but no reinforcing beads, was prepared according to the composition specified below in Table 2.

(37) This composition SGH1 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(38) The whole was cooked at a temperature between 200 C. and 300 C.

(39) TABLE-US-00002 TABLE 2 Mass fraction Components (%) Silicone resin: SILRES 610 resin 40 to 70% marketed by WACKER Silane: aminopropylsilane 5 to 20% Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Cellulosic rheology additive 0 to 5%

Example 3

Hybrid Sol-Gel Composition According to the Invention, with Silanes and Reinforcing Beads

(40) A hybrid sol-gel composition SGH2 according to the invention, containing a silicone resin, reinforcing beads and a silane, prepared according to the composition specified below in Table 3.

(41) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(42) This composition SGH2 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(43) The whole was cooked at a temperature between 200 C. and 300 C.

(44) TABLE-US-00003 TABLE 3 Mass fraction Components (%) Silicone resin: SILRES 610 resin 40 to 70% marketed by WACKER Silane: aminopropylsilane 5 to 20% Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Stainless steel beads 2 to 5% Cellulosic rheology additive 0 to 5%

Example 4

Chelation and Pre-Hydrolysis of a Metal Alkoxide

(45) A composition comprising a metal alkoxide was prepared according to the composition specified below in Table 4 for the purposes of chelating and pre-hydrolyzing said metal alkoxide.

(46) TABLE-US-00004 TABLE 4 Mass fraction Components (%) Chelating agent: acetylacetonate 5 to 20% CAS 123-54-6 Metal alkoxide: titanium isopropoxide 40 to 60% CAS 548-68-9 Water 15 to 30% Acetic acid 1 to 6%

Example 5

Hybrid Sol-Gel Composition According to the Invention, with Metal Alkoxides and Reinforcing Beads

(47) A hybrid sol-gel composition SGH3 according to the invention, containing a silicone resin, reinforcing beads and the prehydrolyzed metal alkoxide from Example 4, was prepared according to the composition specified below in Table 5.

(48) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(49) This composition SGH3 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(50) The whole was cooked at a temperature between 200 C. and 300 C.

(51) TABLE-US-00005 TABLE 5 Mass fraction Components (%) Silicone resin: SILRES 610 resin 40 to 70% marketed by WACKER Metal alkoxide: prehydrolyzed titanium 5 to 25% isopropoxide CAS 548-68-9 (example 4) Solvent: butyl glycol 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Stainless steel beads 2 to 15%

Example 6

Hybrid Sol-Gel Composition According to the Invention, with Silanes, Metal Alkoxides and Reinforcing Beads

(52) A hybrid sol-gel composition SGH4 according to the invention, containing a silicone resin, reinforcing beads as well as a silane and the prehydrolyzed metal alkoxide from Example 4, was prepared according to the composition specified below in Table 6.

(53) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(54) This composition SGH4 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(55) The whole was cooked at a temperature between 200 C. and 300 C.

(56) TABLE-US-00006 TABLE 6 Mass fraction Components (%) Silicone resin: SILRES 610 resin 40 to 70% marketed by WACKER Metal alkoxide: prehydrolyzed titanium 1 to 15% isopropoxide CAS 548-68-9 (example 4) Silane: 3-aminopropyltriethoxysilane 1 to 15% Solvent: butyl glycol 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Stainless steel beads 2 to 15%

Example 7

Hybrid Sol-Gel Composition According to the Invention, with Silanes but No Reinforcing Beads

(57) A hybrid sol-gel composition SGH5 according to the invention, containing a silicone polyester resin and a silane, but no reinforcing beads, was prepared according to the composition specified below in Table 7.

(58) This composition SGH5 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(59) The whole was cooked at a temperature between 200 C. and 300 C.

(60) TABLE-US-00007 TABLE 7 Mass fraction Components (%) Silicone polyester resin: SILIKOFTAL 40 to 70% resin marketed by TEGO Silane: aminopropylsilane 5 to 20% Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Cellulosic rheology additive 0 to 5%

Example 8

Hybrid Sol-Gel Composition According to the Invention, with Silanes and Reinforcing Beads

(61) A hybrid sol-gel composition SGH6 according to the invention, containing a silicone polyester resin, reinforcing beads and a silane, was prepared according to the composition specified below in Table 8.

(62) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(63) This composition SGH6 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(64) The whole was cooked at a temperature between 200 C. and 300 C.

(65) TABLE-US-00008 TABLE 8 Mass fraction Components (%) Silicone polyester resin: SILIKOFTAL 40 to 70% resin marketed by TEGO Silane: aminopropylsilane 5 to 20% Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Stainless steel beads 0 to 5% Cellulosic rheology additive 2 to 15%

Example 9

Hybrid Sol-Gel Composition According to the Invention, with Metal Alkoxides and Reinforcing Beads

(66) A hybrid sol-gel composition SGH7, according to the invention, containing a silicone polyester resin, reinforcing beads and the prehydrolyzed metal alkoxide from Example 4, was prepared according to the composition specified below in Table 9.

(67) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(68) This composition SGH7 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(69) The whole was cooked at a temperature between 200 C. and 300 C.

(70) TABLE-US-00009 TABLE 9 Mass fraction Components (%) Silicone polyester resin: SILIKOFTAL 40 to 70% resin marketed by TEGO Metal alkoxide: prehydrolyzed titanium 5 to 25% isopropoxide CAS 548-68-9 (Example 4) Solvent: 5 to 20% butyl glycol Load: alumina 5 to 20% Mineral pigments: 5 to 20% iron oxide, FeCrCu oxide Stainless steel beads 2 to 15%

Example 10

Hybrid Sol-Gel Composition According to the Invention, with Silanes, Metal Alkoxides and Reinforcing Beads

(71) A hybrid sol-gel composition SGH8, according to the invention, containing a silicone polyester resin, reinforcing beads as well as a silane and the prehydrolyzed metal alkoxide from Example 4, was prepared according to the composition specified below in Table 10.

(72) The reinforcing beads used were stainless steel beads marketed by HOGANAS under the name 316 HIC 15 m.

(73) This composition SGH8 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer according to the invention.

(74) The whole was cooked at a temperature between 200 C. and 300 C.

(75) TABLE-US-00010 TABLE 10 Mass fraction Components (%) Silicone polyester resin: SILIKOFTAL 40 to 70% resin marketed by TEGO Metal alkoxide: prehydrolyzed titanium 1 to 15% isopropoxide CAS 548-68-9 (Example 4) Silane: 3-aminopropyltriethoxysilane 1 to 15% Solvent: butyl glycol 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Stainless steel beads 2 to 15%

Comparative Example 1

Hybrid Sol-Gel Composition, with No Silanes, Metal Alkoxides or Reinforcing Beads

(76) A hybrid sol-gel composition SGHc1, containing a silicone resin but no silanes, metal alkoxides or reinforcing beads, was prepared according to the composition specified below in Table 11.

(77) This composition SGHc1 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer.

(78) The whole was cooked at a temperature between 200 C. and 300 C.

(79) TABLE-US-00011 TABLE 11 Mass fraction Components (%) Silicone resin: SILRES 610 resin 40 to 70% marketed by WACKER Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Cellulosic rheology additive 0 to 5%

Comparative Example 2

Hybrid Sol-Gel Composition, with No Silanes, Metal Alkoxides or Reinforcing Beads

(80) A hybrid sol-gel composition SGHc2, containing a silicone polyester resin but no silanes, metal alkoxides or reinforcing beads, was prepared according to the composition specified below in Table 12.

(81) This composition SGHc2 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a hybrid sol-gel coating comprising a hybrid sol-gel layer.

(82) The whole was cooked at a temperature between 200 C. and 300 C.

(83) TABLE-US-00012 TABLE 12 Mass fraction Components (%) Silicone polyester resin: SILIKOFTAL 40 to 70% resin marketed by TEGO Solvents: xylene and butyl acetate (80/20) 5 to 20% Load: alumina 5 to 20% Mineral pigments: iron oxide, FeCrCu oxide 5 to 20% Cellulosic rheology additive 0 to 5%

Comparative Example 3

(84) A sol-gel composition SGc1 of metal alkoxide precursors that does not contain metal beads was prepared according to the composition specified in the patent document U.S. Pat. No. 6,863,923 as in Example 3.

(85) This composition SGc1 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a sol-gel coating.

(86) The whole was cooked at a temperature between 200 C. and 300 C.

Comparative Example 4

(87) A screen-printed sol-gel composition SGc2 of metal alkoxide precursors containing stainless steel beads, was prepared according to the instructions of patent document FR 2973390, according to the composition specified below in Table 13.

(88) This composition SGc2 was applied in a single screen-printed layer to the sol-gel coating obtained in Example 1, to form a sol-gel coating.

(89) The whole was cooked at a temperature between 200 C. and 300 C.

(90) TABLE-US-00013 TABLE 13 Mass fraction Components (%) Resin or terpene derivatives 20 to 50% Modified sol-gel composition (cf. below) 30 to 50% Mineral pigments 0 to 10% Stainless steel spherical loads 5 to 30%

(91) The modified sol-gel composition for the screen-printed SGc2 composition was obtained as follows: As with the SG1 sol-gel composition, an initial sol-gel composition of a metal alkoxide precursor was prepared as previously defined; This metal alkoxide was then hydrolyzed in a reactor in the presence of water and either an acid or a base (preferably sodium hydroxide, potassium alkalines and alkaline earth metals) followed by a condensation reaction yielding alcohol; Filtration of the resulting sol-gel composition may be necessary if granules have formed during the hydrolysis-condensation reaction (for example, if agglomerates were formed in situ during the hydrolysis-condensation reaction of the metal alkoxide precursors, particularly if the reaction took place under alkaline conditions). The alcohol created via the hydrolysis-condensation reaction was evaporated/distilled out of the sol-gel composition (aided by vacuum evacuation) and was then replaced with a glycol or terpene derivative (terpineol) to form the modified sol-gel composition.

(92) The modified sol-gel composition was then mixed with cellulose (Dow Ethocel STD 20) to increase viscosity and facilitate the screen-printing application. A viscosity ranging from 0.5 to 5 Pa.Math.s (5 to 50 poise) was targeted. The addition of other binders, such as a CMC-type organic binders or xanthan gum, may be used to modify the desired rheology of the serigraphy paste.

(93) In a final step, the metal loads (Hoganas 316 HIC 15 m) are added by dispersion to produce the SGc2 composition.

(94) Results of Conducted Tests

(95) The coated supports produced in Examples 2, 3, and 5 through 10 and in Comparative Examples 1 through 4 were tested for flame resistance, adhesion, abrasion, glass cooktop scratching and gloss, as described above. The results of these various tests are summarized in Table 14 below.

(96) TABLE-US-00014 TABLE 14 (Results): Glass Gloss Suitability cooktop (in points at for scratch a 60 Examples serigraphy Adhesion Flame Abrasion test angle) 2 Acceptable Acceptable Good Very good Light 110 SG1 + SGH1 scratching 3 Acceptable Acceptable Good Very good Good 80 SG1 + SGH2 5 n/d Very good n/d Good Good 60 SG1 + SGH3 6 n/d Very good n/d Good Good 80 SG1 + SGH4 7 Excellent Very good Good Very good Light 100 SG1 + SGH5 scratching 8 Excellent Very good Good Good Good 80 SG1 + SGH6 9 n/d Very good n/d Good Good 60 SG1 + SGH7 10 n/d Very good n/d Good Good 80 SG1 + SGH8 Comparison 1 Acceptable Acceptable Good Good Some 110 SG1 + SGHc1 scratching Comparison 2 Excellent Good Good Good Some 110 SG1 + SGHc2 scratching Comparison 3 Excellent Excellent Excellent Not good Scratching 15 SG1 + SGc1 Comparison 4 Excellent Excellent Excellent Scratch Good 15 SG1 + SGc2

(97) The results in Table 14 show that the hybrid sol-gel coatings according to the invention (Examples 2, 3, and 5 through 10) may be applied by serigraphy and globally have acceptable adhesion to the underlying sol-gel coating. Their flame resistance properties are equally good. However, unlike traditional sol-gels made with metal alkoxide precursors (Comparative Examples 3 and 4), they are resistant to abrasion and may therefore be used on glass-ceramic cooktops, even without necessarily adding metal beads (cf. Examples 2 and 7).

(98) The comparisons of Example 2 with Comparative Example 1 (simple silicone resin) and Example 7 with Comparative Example 2 (silicone polyester resin) demonstrate that the addition of silane to the hybrid coating composition improves resistance to abrasion.

(99) The comparisons of Examples 2 and 3 (simple silicone resin with silanes) with Examples 7 and 8 (silicone polyester resin with silanes) demonstrate that the addition of reinforcing beads to the hybrid sol-gel coating composition that already contains silanes further improves resistance to abrasion.

(100) The comparison of Example 2 (simple silicone resin) to Example 7 (silicone polyester resin) demonstrates that switching from a simple silicone resin to a silicone polyester resin further improves suitability for serigraphy.