KR20150096476A - Enamel coating comprising anisotropic particles and cooking item provided with such a coating - Google Patents

Abstract

The invention relates to an enamel layer (31) comprising at least one layer (31) of enamel in which particles (4) having an anisotropic shape are dispersed, said layer being characterized in that said anisotropic particles And at least one region (5) essentially comprising the particles (41) perpendicular to one another. The present invention also relates to articles comprising such coatings, for example cooking utensils, and methods of applying such coatings to substrates.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an enamel coating containing an anisotropic particle and a cooking article provided with such an enamel coating.

The present invention relates generally to articles comprising an enamel coating comprising anisotropic particles (flakes or fibers) which can be used on any type of substrate, especially a metal substrate.

The present invention also relates to a method of applying such a coating to a support.

The target area is mainly heating products.

For purposes of the present invention, a "heating article" may be an article comprising a self-heating system, an article heated by an external system to contact the article to transfer heat energy generated by the system to a third article or article ≪ / RTI > or an article designed to receive another preheated article.

Examples of heating appliances that may be used in accordance with the present invention include, but are not limited to, cooking utensils (e.g., sauce pan, casserole, wok, crepe pan, crock pot, cooking pot, casserole, etc.), heating covers and heating blender bowls of food or beverage making equipment . However, the present invention is also applicable to any other type of surface and article such as tableware such as trivets, iron base, curling iron, straightening iron, radiator, towel rail, wood stove, barbecue grill, barbecue box, It may be about kiln goods.

The enamel coating is particularly well suited for heating appliances, especially cooking utensils, and irons, and more particularly in the field of sole plates.

In the case of an iron base, the tribological, thermal and physiochemical properties of the coating are the basis for ensuring easier ironing. Thus, enamel coating is an ideal compromise for coating the metal frame of an iron base, since it has a low coefficient of friction that holds heat well and does not significantly change by temperature, and is hydrophilic and hydrolyzable. A disadvantage of enamel coatings for applications such as irons (especially steam irons, dry irons and steam generators) is its low impact resistance. In fact, small enamel fragments may appear on the coated edge of the enamel cap (more specifically around the coated cap), especially when the coating is impacted during use. Small enamel fragments may also appear through repeated contact with metal components (buttonholes, snaps, zippers, etc.) located on the textile to be ironed.

The enamel coating also makes it possible to obtain a colored coating with a basic decorative appearance that is well tolerated in a dishwasher and is highly resistant to flame and scratching as well as often a deciding factor in consumer choice, Particularly suitable. However, they have the disadvantage that the cooking utensils are easily peeled off in certain particularly sensitive areas, experiencing the greatest wear and tear. These areas are generally located on the curved portion of the article or on a connection close to the handle.

The sensitive areas for the cooking utensils include, in particular, the areas where the bottom and sidewalls of the article meet, the upper edge of the article rounded (deformed) to create a smooth, flat edge, the area supporting the connection of the handle , And a bottom that comes into contact with the burner.

In addition, the enamel coating also undergoes various degrees of thermal expansion depending on the location of the flame underneath the article. However, it is important for the coating to have uniform thermal expansion, otherwise micro-cracks will occur and resistance to dishwashing will be reduced.

In order to avoid the above-mentioned problems, Applicants have developed an enamel coating containing essentially vertically oriented flakes, generally anisotropic particles, for the coating formed in the sensitive area.

For purposes of the present invention, "essentially vertically oriented particles for coating" means that most of the particles are oriented at an angle of 20 to 90, preferably 45 to 90, and preferably 60 Means an inclined particle at an angle [alpha] to 90 [deg.].

It is well known to those skilled in the art to incorporate particles, such as flakes, into an enamel-type coating. Thus, for example, French patents FR 2472596 and FR 813737 describe enamel coatings for cooking utensils incorporating mica or nacreous flakes in an enamel coating.

International applications WO 2011/42886 and U.S. Patent 3,480,461 also relate to decorating an iron base using an enamel coating comprising a pigment or a filler.

However, none of these references describe any particular grain orientation (flake, pigment or filler) for a particular area of the coating, particularly for the purpose of reinforcing the area, Is achieved by using the magnetic field of the magnetic field.

More particularly, the present invention relates to a method of forming a protective layer comprising a support having two opposing faces, at least one of the opposing faces being covered by a protective coating, the protective coating comprising at least one enamel layer, The enamel layer being characterized in that the anisotropic particles comprise at least one region which is essentially perpendicular to the enamel layer in the form of a film.

The anisotropic particles may advantageously represent from 0.05 to 10% by weight, preferably from 0.1 to 7% by weight, optimally from 1 to 5% by weight of the total weight of the enamel layer. Ideally, the anisotropic particles represent 2 to 3% by weight of the total weight of the enamel layer 31.

In areas where the particles are essentially vertical, the resistance to scaling and impact is significantly improved. Also, the thermal expansion of the region is not different from that of the remainder of the coating.

For purposes of the present invention, "anisotropic particles" means particles, such as fibers (essentially one-dimensional shape) or flakes (essentially two-dimensional or flat shape) whose dimensional properties are not identical in all directions.

For purposes of the present invention, "particles essentially perpendicular to the film" means particles that are mostly inclined at an angle of 20 to 90 relative to the average plane of the film.

Depending on the type of anisotropic particles used, this orientation of the anisotropic particles can be obtained in a variety of ways.

Thus, in the case of particles (e.g., fibers) that can be oriented by mechanical means, orientation that is essentially perpendicular to the coating layer can be achieved, for example, by a coating application method (for example using a unidirectional applicator such as a micro- As shown in Fig.

In the case of particles that can be oriented by physical means (e. G., Electrical or magnetic), the essentially vertical orientation of the anisotropic particles relative to the coating layer can be controlled by, for example, Such as by orienting the dialyzable particles under the < RTI ID = 0.0 > a < / RTI >

For purposes of the present invention, "magnetizable particle" means a particle that can be oriented under the effect of a magnetic field.

Various types of magnetizable particles can be used.

In the present invention, the magnetizable particles may advantageously be particles comprising at least one ferromagnetic metal.

They can be homogeneous, i.e. they can consist of the same material or composite, i.e. the magnetizable particles have a core-shell structure in which the ferromagnetic metal is in the core and / or in the shell of the particle.

One specific example of composite magnetizable particles is a mica flake coated with a ferromagnetic material, such as a mica flake coated with a ferrite of the form (MO, Fe ₂ O ₃ ), where M is a divalent metal, For example, Fe ₃ O ₄ (magnetite) or Fe ₂ O ₃ or FeO. Other materials with ferromagnetic properties: Heusler alloys (61% Cu, 24% Mn and 15% Al) consisting solely of cobalt, nickel or non-ferromagnetic metals, or certain rare earths such as lanthanide, or Copper-manganese and aluminum oxide may also be used.

The advantage of the coated mica flakes is that they are particularly resistant to a high firing temperature of the enamel for the metal, i.e. from 550 DEG C for enamel on aluminum to 850 DEG C for steel or enamel on cast steel. In addition, these mica flakes are more resistant to alkalinity of the enamel slip generated by hydrolysis (e.g., in the case of aluminum, the enamel slip has a pH of 13). It may also refer to stainless steel fibers coated with a sol-gel material to provide corrosion protection during various stages of coating application, or flakes whose core consists of a ferromagnetic metal and whose shell is a sol-gel material.

Coatings according to the present invention may also advantageously include non-magnetizable particles to improve coating strength.

For purposes of the present invention, "non-magnetizable particles" means non-magnetizable or slightly magnetizable particles with zero or low magnetic moment (less than 1 uem / g).

These non-magnetizable particles can have any shape (spherical, fiber, flake or "irregular") and can be micrometers or even nanometers in size.

The non-magnetizable particles that can be used in the present invention are in particular mica flakes, or mica or silica flakes coated with titanium dioxide.

The protective coating of the present invention may also advantageously comprise at least one substantially parallel and / or random at least one substantially parallel to and / or adjacent to the enamel film layer, adjacent to an area essentially perpendicular to the enamel coating layer, As shown in FIG.

For purposes of the present invention, "essentially parallel to the enamel coating layer" means particles that are mostly inclined at an angle of 0 to 20 relative to the coating layer.

The alternation of areas where the particles are essentially parallel and / or random with respect to the enamel layer, and areas where the particles are essentially perpendicular to the enamel layer, can produce a pattern that the user can perceive as a three-dimensional fringe element.

According to a particularly advantageous first embodiment of the invention, the enamel layer of the protective coating according to the invention may comprise a single continuous layer designed to be applied to the support.

According to a particularly advantageous second embodiment of the present invention, the enamel layer of the protective coating according to the invention comprises

A transparent sublayer which is continuous and which is designed to be applied to a support, which does not contain magnetizable particles, and

- a continuous, partially or completely covering sublayer, of a self-assembled particle-dispersed finish layer

. ≪ / RTI >

For purposes of the present invention, "finish layer" means a layer designed to contact the environment.

According to a particularly advantageous third embodiment of the present invention, the enamel layer of the protective coating according to the invention comprises

A colored sublayer which is continuous and which is designed to be applied to a support and which does not contain magnetizable particles, and

- a continuous, partially or completely covering sublayer, of a self-assembled particle-dispersed finish layer

. ≪ / RTI >

According to a fourth aspect of the invention, which is particularly advantageous, the enamel layer of the protective coating according to the invention comprises

A transparent or colored sublayer which is continuous and which is designed to be applied to a support, which does not contain magnetizable particles,

A first finish layer which is continuous and completely covers the sublayer, in which magnetic particles are dispersed, and

Magnetic particles which are continuous and partially or fully covering the first finish layer are also dispersed in the second finish layer

. ≪ / RTI >

According to a particularly advantageous fifth embodiment of the present invention, the enamel layer of the protective coating according to the invention comprises

A colored sublayer in which magnetic particles are dispersed and designed to be continuous and applied to a support, and

- magnetic particles which are continuous and partially or completely cover the sublayer are also coated with a dispersed transparent finish layer

. ≪ / RTI >

One such embodiment has the advantage of mechanically strengthening the mechanical bond between each layer and each layer.

Advantageously, in embodiments having at least two layers (second through fifth embodiments), the sublayer may have a thickness of from 5 to 30 μm and the finish layer (s) may have a thickness of from 20 to 60 μm Lt; / RTI >

According to a particularly advantageous sixth embodiment of the present invention, the protective coating according to the invention comprises

연속적이고 지지체에 도포되도록 설계된, 자화성 입자를 함유하지 않는 투명 또는 착색 하위층, 및-

A transparent or colored sublayer which is continuous and which is designed to be applied to a support, does not contain magnetizable particles, and

착색 층 또는 자화성 입자(41)가 분산된 자화성 층이며, 연속적이고 상기 하위층(310)을 부분적으로 또는 완전히 덮는 적어도 하나의 중간층(313)

At least one intermediate layer 313 continuous and partially or completely covering the sublayer 310, the coloring layer or the magnetizable layer 41 being a dispersed magnetic layer,

An enamel layer comprising

A first layer of continuous magnetizable polish dispersed with magnetizable particles partially or completely covering the intermediate enamel layer, and

- a second layer of a non-colored transparent non-magnetizable continuous polish completely covering the first layer of magnetic polishes and ensuring chemical resistance and resistance to dishwashing;

. ≪ / RTI >

Advantageously, in this sixth embodiment, the sublayer may have a thickness of from 5 to 30 μm, and the middle enamel layer may have a thickness of from 20 to 60 μm. With respect to the polish layer covering the intermediate enamel layer, the magnetizable polish layer may advantageously have a thickness of from 15 to 40 μm and the protective polish layer may have a thickness of from 10 to 20 μm.

In all such embodiments, for the purposes of the present invention, a "colored layer" (whether sublayer, finish layer or polish layer) is a thermally stable pigment such as spinel, ceramic pigment, oxide, organometallic such as ultramarine, Quot; means a layer containing at least one opacifying pigment selected from the group consisting of (non-magnetizable) mica or silica flake pigment, metal salt, thermochromic semiconductor pigment or combinations thereof.

Advantageously, regardless of the embodiment, the enamel layer of the protective coating of the heating article according to the invention may also comprise a discontinuous outer enamel layer added by silk screening or pad printing.

If the heating article according to the invention is a cooking article, the outer enamel layer may also comprise a round filler, which is advantageously spherical with a diameter of from 5 to 40 μm, preferably from 15 to 20 μm, 32) varies from 10 to 30 占 퐉. These beads protrude from the surface of the outer enamel layer.

Circular fillers (or beads) suitable for use in the outer enamel layer according to the present invention include, in particular, stainless steel, copper, bronze or refractory steel beads.

Preferably, stainless steel beads are used. The round filler is advantageously present in the outer enamel layer at 1 to 5 weight percent of the total weight of the outer layer. These circular fillers increase the wear and tear resistance of the enamel coating and also provide a lower contact surface between the article and the cooking surface (when the filler is at the same height as the enamel layer surface) Hardness reduces the coefficient of friction. Thus, the coating may be easily cleaned and may not have the risk of scratching of sensitive surfaces, such as ceramic glass or induction cooktop.

The support of the article may be made of metal, glass or ceramic.

The metallic support according to the present invention comprises

- a single layer made of polished, brushed, micro-beaded, sanded or chemically treated aluminum or aluminum alloy, or cast aluminum, or polished, brushed, micro-beaded stainless steel or cast steel or aluminum Type structure, or

- Aluminum or aluminum cast aluminum, stainless steel / aluminum / copper / aluminum / austenitic stainless steel or stainless steel bottom lining, wholly or partly, from ferritic stainless steel to aluminum to austenitic stainless steel or from stainless steel to aluminum Or a layer of a cap of an aluminum alloy.

.

Examples of articles according to the present invention are, in particular, cooking utensils, heating covers, or cooking utensils such as heated blender bowls, iron base plates, trivets, radiator or wood stoves, curling irons and straightening irons, Towel rails or barbecue grills, boxes or tanks.

Finally, it is also an object of the present invention to apply a method of producing a coating comprising at least one enamel layer on which an anisotropic particle is dispersed, on a heating article support, which comprises applying the anisotropic particle to at least one (E.g., using an electric or magnetic field) or mechanical means (e.g., when the coating is applied using a unidirectional applicator, such as a micro-nozzle, for example) .

The support and anisotropic particles are as defined above.

Advantageously, the process according to the invention

a) providing a support;

b) applying on the one of the support surfaces at least one enamel composition dispersed with anisotropic particles, including magnetizable particles, by micronisation;

c) orienting the magnetizable particles by applying a magnetic field, said magnetizing step c) being effected during step b) of applying the enamel composition to a support, or immediately after said application step b); next

d) optionally, drying at a temperature of from ambient temperature to 150 캜; next

e) firing at a temperature of at least 500 < 0 > C

. ≪ / RTI >

The magnetizable particles are those defined above.

In this embodiment of the method according to the invention, anisotropic magnetizable particles are used; The orientation step d) of the magnetizable particles is thus a magnetization step carried out by applying a magnetic field, which is carried out either before or after the application step d), but just before the firing step e).

After drying and firing, a protective coating with high resistance to scaling and impact and homogeneous thermal expansion throughout the coating is obtained.

In this embodiment of the process according to the invention in which the anisotropic particles are magnetizable and oriented by magnetization, the enamel layer application step b)

- b1) a sub-step of forming an uncured sublayer on one of the support surfaces by micronisation of a transparent or colored sublayer enamel composition containing no magnetic particles; next

- b2) a sub-step of forming an uncured enamel finish layer on the uncured sublayer by milling of at least one enamel finish composition dispersed with magnetizable particles

. ≪ / RTI >

Preferably, the enamel layer application step b) further comprises, after step b2), but prior to the firing step e), on the uncured enamel finish layer, at least one second enamel finish composition in which magnetizable particles are also dispersed And b3) forming a second uncured enamel finish layer 312 by micronisation.

Finally, the process according to the invention is also characterized in that after the drying step d) of the formed finish enamel layer (s) (and thus the drying step in this embodiment is no longer optional and necessary) And applying a layer of enamel paste that may not be clear to the enamel finish layer.

These circular fillers (or beads) are those defined above.

Other advantages and particularities of the invention will be apparent from the following description, given by way of non-limiting example, and reference is made to the accompanying drawings, in which:

1 shows a schematic cross-sectional view of a part of the support of the article according to the invention according to the first embodiment;

2 shows a schematic cross-sectional view of a part of the support of the article according to the invention according to the second embodiment (which shows two sub-embodiments 2a and 2b);

3 shows a schematic cross-sectional view of a part of the support of the article according to the invention according to the third embodiment (which shows two sub-embodiments 3a and 3b);

4 shows a schematic cross-sectional view of a part of the support of the article according to the invention in accordance with the fourth embodiment;

5 shows a schematic cross-sectional view of a part of the support of the article according to the invention according to the fifth embodiment (which shows four sub-embodiments 5a to 5d);

6 shows a schematic cross-sectional view of a part of the support of the cooking utensil according to the invention according to the sixth embodiment;

7 shows a schematic cross-sectional view of a part of an iron base plate consistent with the invention according to the seventh embodiment;

8 is a bottom view of the bottom plate of the iron shown in Fig. 7; Fig.

9 shows a schematic cross-sectional view of the arrangement of the magnets under the support of the coated article for carrying out the magnetization step;

10 is a detail view of FIG. 9 showing area Z (defined by the edges and gaps of the two magnets); FIG.

11 is a top view (photograph) of a part of an iron base plate in which the lower permanent magnet is placed in the form of a triangular band;

12 is a detail view of FIG. 1 showing a particular area Z (defined by the edges and gaps of two magnets); FIG.

13 shows a series of three images 13a to 13b from a scanning electron microscope (SEM) of the section of the iron base plate of Fig. 3 showing a specific area Z. Fig.

Figure 1 shows a part of the support of the article according to the first embodiment. One of the faces 21 of the support 2 is provided with a continuous monolayer film 31 of enamel coating in which anisotropic particles 41 are dispersed.

Figure 1 shows that the film 31 comprises at least one region 5 in which the anisotropic particles 41 are essentially perpendicular to the film 31.

This particular orientation of the anisotropic particles 41 in the region 5 can be achieved, for example, by magnetization when the anisotropic particles 41 contain magnetizable particles. Actually, it proceeds as follows: adjacent to the uncoated surface 22 below the support 2 there is a permanent magnet, especially an elastomeric magnet (which limits the magnetization condition to a temperature below 80 ° C) or electromagnet. It is also possible to use ferrite or neodymium permanent magnets or electro-induction magnets. In this case, then the maximum temperature of the magnetizing conditions may exceed 80 ° C, but it should be kept below the Curie point of the magnet used. To obtain a particular holographic image, a magnet having the desired shape is used, which is cut and / or machined using permanent and electro-induced ferromagnetic materials.

Preferably, magnets having a magnetic field strength of 40 to 100 mT, preferably about 70 mT are used.

Figure 1 shows that the magnetizable particles 41 of the monolayer enamel film 31 are perpendicular to the film in the region 5 along a field line produced by a permanent magnet positioned directly below a specific region 5, Lt; / RTI >

 Figure 2 shows a schematic cross-sectional view of a part of the support 2 of the article according to the invention in accordance with the second embodiment, which shows two sub-embodiments as shown in Figures 2a and 2b, respectively. The two sub-embodiments shown in Figs. 2A and 2B differ from the embodiment shown in Fig. 1 in that the enamel coating in the form of film 31 is a bi-layer.

In the two sub-embodiments shown in Figures 2a and 2b, the bilayer coating 31 comprises a sublayer 310 (not containing anisotropic particles) layered on one of the faces 21 of the support 2 And one finish layer 311 in the form of a continuous enamel film that covers the lower layer 310, wherein the anisotropic particles 41 are contained within the finish layer 311. The lower layer 210 may be colored as shown in FIG. 2A, or may be transparent as shown in FIG. 2B. The orientation of the anisotropic particles 41 can be achieved by the magnetization of the anisotropic particles 41 in the case of containing magnetic particles in the same manner as in the first embodiment.

Figure 3 shows a schematic cross-section of a part of the support of the article according to the invention according to the third embodiment, which also has the two sub-embodiments shown in Figures 3a) and 3b respectively. Each of these sub-embodiments 3a) and 3b) is characterized in that the double-layer enamel coating 31 has a second finish layer 312 in which the anisotropic particles 41 are also dispersed, Lt; / RTI > embodiment.

Figure 3 also shows that the layered enamel coating 31 of Figure 3 has a region 6 with anisotropic particles 41 essentially parallel to the coating 31 and anisotropic particles 41 essentially perpendicular to the film Dimensional pattern generated by interchanging the region 5 having the light-shielding film 5 and the light-shielding film 5 having the light-shielding film 5.

Here again, the particular orientation of the anisotropic particles 41 in the region 5 will be achieved by magnetization if the anisotropic particles are magnetizable.

Thus, in the case of a cooking article in which the bottom of the support designed to be coated is generally circular, this magnetization is formed on the side of the uncoated side 22 below the support (generally circular) For example, by placing a plurality of concentric elastomer permanent magnets that independently emit a constant intensity or variable strength magnetic field of about 80 mT. Such a concentric magnet may advantageously be formed as a plurality of concentric rings located around the center disc with a small diameter (e.g., 15 mm or less) and a width of about 10-15 mm. Such a magnet can advantageously be placed on a substrate (e.g. a stainless steel plate) which is vertically movable relative to the article support. This movement can be accomplished using a jack that moves the substrate (or plate) to create a gap near the article to be magnetized.

In the case of an iron base with a generally triangular cap designed to be coated, for example, a band magnet (made, for example, of an elastomer) is provided on the side of the uncoated side 22 below the area to be strengthened of the support 2 Lt; / RTI > These bands may be continuous or discontinuous, and generally have a triangular cap. Which emits a magnetic field of constant intensity or variable intensity, measured independently, for example, approximately 80 mT.

The magnetically anisotropic particles are then oriented perpendicular to the support 2 (or the film 31) (the reverse line is perpendicular to the enamel coating 31) along the opposite line, And a progressive alignment continuum of magnetisable anisotropic particles between these two zones, parallel to the support 2 (and thus to the coating 31) in the region 6 parallel to the support 2, .

Figure 4 shows a schematic cross-sectional view of a portion of the support of the article consistent with the present invention according to the fourth embodiment, which is characterized in that the lower layer 310 contains anisotropic particles 41, Embodiment as shown in FIG. Layer enamel coating 31 of Figure 3 comprises a region 6 having anisotropic particles 41 essentially parallel to the coating 31. The layer 6 has an anisotropic particle 41 substantially parallel to the coating 31, And a region 5 having anisotropic particles 41 which are essentially perpendicular to the film. If the anisotropic particles 41 contain magnetic particles or are magnetic particles, the grain orientation in the region 5 can be achieved by including a magnet under the support 2.

Figure 5 shows a schematic cross-sectional view of a part of the support of the article according to the invention according to the fifth embodiment, the fifth embodiment showing four sub-embodiments in Figures 5a) to 5d respectively. These drawings

(As shown in Figures 5A and 5B) or colored (as shown in Figures 5C and 5D) sublayer 310 that does not contain magnetizable particles 41,

An intermediate layer 313 which is continuous and which covers the sublayer 310, is a magnetizable layer in which a coloring layer (as shown in Figures 5b and 5d) or anisotropic particles, preferably magnetizable particles 41,

(21) with one of the surfaces coated with an enamel layer.

The intermediate layer 313

- a first layer (321) of anisotropic particles (41), preferably transparent or colored continuous polish dispersed with magnetizable particles, and

- a second layer (322) of non-colored continuous polish completely and / or partially covering the first layer (321)

By itself.

Here again, the particular orientation of the anisotropic particles 41 in the region 5 can be achieved by magnetization if the anisotropic particles are magnetizable.

Fig. 6 shows a schematic cross-sectional view of a part of the support of the cooking utensil according to the invention in accordance with the sixth embodiment. In this embodiment specific to the cooking utensil, such as the fan 1, the support 2 comprises an inner surface 22 which is the surface facing the food which can be placed in the pan 1 and an outer surface 22, (21). The support 2 has an anti-adhesion coating 7 (e.g. a sol-gel or fluorocarbonated resin) on its inner side 22 and on its outer side 21

- a continuous colored enamel layer (31) containing magnetizable particles (41)

- a continuous uncolored varnish layer in which magnetizable particles (41) are dispersed,

A non-continuous outer enamel layer 33 produced by silk screening or pad printing, containing metallic beads 34 (copper, bronze or refractory steel)

(3). ≪ / RTI >

Fig. 7 shows a schematic cross-sectional view of a part of an ironing base consistent with the present invention according to the seventh embodiment, and Fig. 8 shows a bottom view of the ironing base shown in Fig.

In this specific embodiment of the iron base plate, the support 2 has a coating 3 essentially the same as that shown in Fig. 6 on its outer surface 21 designed to contact the garment to be ironed: It is the absence of the circular filler in the outer enamel layer 33.

Figures 9-13 are shown in greater detail in the following examples illustrating the invention without limiting its scope.

In this embodiment, unless otherwise stated, all percentages and parts are expressed in percent by mass.

Example

Testing resistance to scaling

The ability to withstand the scaling of various protective coatings of similar thickness (70-80 [mu] m) applied to the same metallic substrate was evaluated as follows.

These coatings were applied to scratches of 10 mm length produced by a diamond point calibrated to a diameter of 50 μm with a gradual increasing force from 0 to 5 Newtons. To do so, we used a device available from CSM Instruments under the name "Microscratch tester ".

After the scratches were formed, the minimum force required for the coating to scale until the metal was visible was determined under a microscope (see results in Table 3).

product

Support

- a cooking utensil support made of an aluminum alloy (e. G., Alloy 4917)

- an iron base plate made of aluminum alloy (for example, alloy 3003)

- a cooking utensil support that is cast steel or sheet steel

Ferromagnetic flake

In the present invention, the ferromagnetic flakes usable in the B1 and V1 compositions include:

- iron oxide coated mica flakes (magnetizable flakes) sold under the name STAPA TA Ferricon 200 by EKCART,

- iron oxide coated mica flakes (self-flaky flakes) sold under the name Blue or Green Color or Colorona Blackstar by Merck,

Uncoated mica flakes (non-magnetizable flakes) marketed under the name Iriodin 119 by Merck.

Filler

- Stainless steel bead.

Composition

A colored enamel slip composition B1 containing a magnetic filler for an aluminum substrate (e.g., a cooking article made of aluminum or cast aluminum, an iron base plate, etc.) B1

Enamel frit slip B1 of the composition given in Table 1 below was prepared.

<Table 1>

The values shown are parts by weight based on 100 parts by weight of frit (reference amount of slip composition).

The composition of enamel frit F1 is given in Table 2 below.

<Table 2>

The value shown is the mass percentage for frit mass.

Enamel slip composition B2 for the support of casting steel cooking utensils

Enamel frit slip B2 of the composition given in Table 3 below was prepared.

<Table 3>

The values shown are parts by weight based on 100 parts by weight of frit (reference amount of slip composition).

The composition of enamel frit F2 is given in Table 4 below.

<Table 4>

The value shown is the mass percentage for frit mass.

A colored brightener composition V1 containing a magnetic filler

Brightener compositions V1 of the compositions provided in Table 5 below were prepared.

<Table 5>

White cover enamel slip composition B3 for cast steel (containing magnetic filler)

A colored enamel frit slip B3 designed to produce a white cover enamel was prepared. Its composition is given in Table 6 below.

<Table 6>

Table 7 shows the composition of the frit F3 used in the white cover enamel.

<Table 7>

Silk screening paste composition (with and without a round filler)

A first silk screening paste composition P3 having the composition given in Table 8 below was prepared without containing filler.

The second silk screening paste composition P4 of the composition given in Table 8 below was also prepared containing the filler.

<Table 8>

Example 1: Preparation of a protective coating according to the invention on the outer surface of an aluminum alloy cooking utensil support.

Using finely pulverized slip B1 of the composition given in Table 1 was applied to the outer surface of the aluminum alloy cooking utensil support to form an enamel layer 31 (approximately 35 탆 thick). A varnish V1 of the composition given in Table 2 was then applied to the enamel layer 31 to produce a varnish layer 32 (approximately 35 um thick).

The magnetizable flakes contained in the enamel layer 31 and the gloss agent layer 32 are coated with two (preferably two), two or more, Immediately after being applied to these layers, permanent magnet (51, 52) was used, with a 70 mT magnetic field, to orient in certain areas of the protective coating using magnetization. Under the influence of the magnetic field, the mica flakes were oriented essentially perpendicular to the magnets, in particular in the regions P1 and P2 shown in FIG. 9, due to their magnetic iron oxide coating.

In order to promote this flake orientation, it is desirable that the viscosity of the applied layer is as low as possible. To this end, a small amount of heavy non-COV solvent such as hexylene glycol was added to reduce evaporation during milling and to increase the duration of application of the magnet to facilitate orientation after milling. Thus, any drying step of the enamel layer could be removed before orientation of the magnetic filler. However, magnets could be applied until the final drying of the coating to enhance orientation. This mode is especially recommended when a design with a clear relief effect is desired.

These layers were then dried at a temperature of less than 150 DEG C, preferably 60 to 80 DEG C to achieve a dry biscuit, and the enamel paste P3 (containing steel beads) of the composition given in Table 4 was silk screened to form a discontinuous outer enamel Layer 33 was formed. The article was then calcined in a standard convection or spinning oven at 500-1000 &lt; 0 &gt; C for 5-30 minutes, depending on the support to be coated.

This coating was observed under a scanning electron microscope (SEM) in the area Z to produce the SEM image shown in FIG. 13 (for the iron base plate), which showed:

The flakes tend to be oriented perpendicular to the support in the region C in which the reverse line is perpendicular to the support 2, i.e. in the region 5 corresponding to the region 5 Present at an inclination angle with respect to the support) (Fig. 13C)

- the flakes tend to be oriented parallel to the support (i.e., most of them are present at an inclination angle relative to the support of less than 20 [deg.]), Where the reverse line is perpendicular to the support 2 And the region B corresponding to the region 6).

Example 2: Preparation of the protective coating according to the invention on a cap on an iron base plate.

The same coating as in Example 1 was applied to the cap of the iron base plate, which did not contain steel beads in the outer enamel layer (this outer enamel layer was produced using silk screening paste P4 which does not contain steel beads).

The magnetizable particles are dispersed in two permanent magnets 51, 52 (in this case, below the surface of the support opposite to the coated surface) of the substrate as shown in Figures 9 and 10 and indeed in Figure 11 ) As in Example 1 under a 70 mT magnetic field. Under the influence of the magnetic field, the mica flakes were oriented perpendicular to the inverse line, i.e., essentially perpendicular, because they were coated with magnetic iron oxide (region C).

A scanning electron microscope (SEM) image of the region Z of this coating is shown in Fig. 13 (Figs. 13A to 13C show regions A to C, respectively).

An optical microscope image of the area Z of this coating is shown in Fig. 12, wherein the various areas A, B and C can be viewed sequentially. In this figure,

The area C (corresponding to reference numeral 5 in Figs. 1 to 7) which is the area between the two magnets 51 and 52, whose magnetic filament is perpendicular to the support, (Due to their vertical position relative to the support), it is a black area,

The area B (corresponding to reference numeral 6 in Figs. 1 to 7) located at the edge of the magnet 51, where the reverse line is parallel to the support, is a region where the reflection of the magnetizable particles is strongest, Area;

The area A essentially defined as the center part of the magnet 51 is such that the magnetizable particles are oriented at an intermediate angle (greater than 20 but less than that shown in area C) relative to the support, (Between those observed in region B and those observed in region C).

Example 3: Preparation of the protective coating according to the invention on the inner and / or outer surface of a cast steel serving article support.

This article will normally be made in two layers in two firing sessions.

The first layer of generally opaque enamel slip B2 (see Tables 5 and 6) was applied to the inner and outer walls of the foodstuff support made of cast steel, blasted and cleaned first, using micronization. This layer will be fired at 800 DEG C to 850 DEG C for 4 to 12 minutes.

It is possible to use ferromagnetic flakes for the first layer: if they are used, their orientation will be facilitated when the enamel is still liquid, i. E. When applying magnets before drying and firing. Drying will ensure that the orientation of the flakes applied to the magnetic field of the magnet is maintained.

The enamel article having the first layer was fired and cooled, then covered enamel slip B3 was applied.

This second layer will be 100-200 [mu] m thick. This layer will increase the mechanical strength to the flake orientation when a magnetic field is applied. This step will be enhanced and facilitated if the enamel slip is still liquid (enhanced mobility). This second firing should be from 750 ° C to 820 ° C for 4 to 12 minutes.

In the case of cast steel for cooking applications or small appliances applications, the enamel described above may be applied to the interior of the article or to the exterior of the article. Their mechanical properties may be enhanced on the inside of the article (to withstand a number of contacts with a foil, knife, spatula, etc.) or on the outside of the article (to withstand cooktop, sink, oven rack, etc.).

The coatings described above provided significant improvement compared to the same coating that did not contain magnetizable flakes oriented in slip B3. Optimized resistance to scaling has been beneficial, for example, when impacting metallic instruments during regular use.

The increase in resistivity could be measured using a non-standardization test using a 300 g hammer falling from the height of 15 cm to the surface of the casting enamel article in less than one second. In the case of using flakes on the slip, the impact did not cause scaling and scaling was present without flakes.

Comparative Example 4: Preparation of a protective coating containing no magnetic particles, applied to the outer surface of an iron base plate.

Similar to Example 2, a protective coating comprising an enamel layer 31 was produced, on which a silk-screen enamel layer 33 was added followed by a polish layer 32. The protective coating in Comparative Example 1 was different from the protective coating of Example 1 in that the enamel layer 31, polish layer 32 and the magnetizable flakes in the silk-screen enamel layer 33 were absent.

Example 5 Evaluation of Scaling Resistance for Aluminum Cookware

The ability of the protective coating to resist scaling in areas (B and C) in Example 2 as well as in Comparative Example 2 (no specific areas because there is no magnetization) was evaluated according to the test described above. The results are shown in Table 9 below.

<Table 9>

The delamination values shown in Table 5 correspond to the average metal fragment values of four measurements per sample.

The comparison of the delamination value measured in region B in Example 1 or 2 with the value from Comparative Example 2 indicates that horizontal flakes can facilitate interlayer delamination so that when no magnetizable flakes are present Indicates that the force required to obtain delamination reaching the metal during the test is low when the particles are oriented parallel to the coating.

Comparison of the values measured in region B of the same embodiment with the delamination values measured in region C of Example 1 or 2 indicates that when the particles are oriented perpendicular to the coating rather than when they are parallel, It clearly indicates that the force required to obtain delamination reaching the metal during the test is high, which means that the scaling resistance is higher when the coating contains oriented particles. In this case, they play a reinforcing role.

Claims (30)

Characterized in that it comprises a support (2) having two opposing faces (21, 22), at least one of which is covered by a protective coating (3)
Characterized in that the protective coating (3) comprises at least one enamel layer (31) in which anisotropic particles (4) are dispersed, the enamel layer being characterized in that the anisotropic particles (4) Characterized in that it comprises at least one region (5) which essentially comprises phosphor particles (41). The article of claim 1, wherein the particles (4) represent 0.05 to 10% by weight of the total weight of the enamel layer (31). 3. The article of claim 2, wherein the particles (4) represent from 0.1 to 7% by weight of the total weight of the enamel layer (31). 4. An article according to claim 3, wherein the particles represent from 1 to 5% by weight, preferably from 2 to 3% by weight, of the total weight of the enamel layer (31). 5. The article of any one of claims 1 to 4, wherein the particles comprise particles (41) that can be oriented by mechanical or physical means. 6. The article of claim 5, wherein the particles (41) that can be oriented are magnetizable particles. 7. The article of claim 6, wherein the magnetizable particles (41) comprise at least one ferromagnetic metal. 8. The article of claim 6 or 7, wherein said enamel layer (31) further comprises non-magnetizable particles. 9. An article according to any one of claims 6 to 8, wherein the magnetizable particles (41) and any non-magnetizable particles have a core-shell structure. The article of claim 9, wherein the ferromagnetic metal of the magnetizable particles (41) is within the core of the particles (41) and / or within the shell. The method of claim 10, wherein the chemical conversion character particles 41, the iron oxide is Fe ₃ O ₄ or Fe ₂ O ₃ flakes or the coated article to FeO. 12. A method according to any one of the preceding claims, characterized in that adjacent the region (5), the anisotropic particles (4) are randomly or at least one region (6) located essentially parallel to the enamel layer &Lt; / RTI &gt; 13. An article according to claim 12, wherein the alternating areas (5 and 6) produce a pattern. 14. A method according to any one of claims 6 to 13, characterized in that the enamel layer (31)
A transparent sublayer 310 that is continuous and free of magnetizable particles 41, designed to be applied to the support, and
- at least one finish layer (311) in which the magnetizable particles (41) are dispersed, which is continuous and partially or completely covers the sublayer (310)
(3). &Lt; / RTI &gt; 14. A method according to any one of claims 6 to 13, characterized in that the enamel layer (31)
- a colored sublayer (310) that is continuous and free of magnetic particles (41), designed to be applied to the support, and
A finishing layer 311 which is continuous and partially or completely covering the lower layer 310, in which the magnetizable particles 41 are dispersed,
(3). &Lt; / RTI &gt; 14. A method according to any one of claims 6 to 13, characterized in that the enamel layer (31)
A transparent or colored sublayer 310 that is continuous and free of magnetizable particles 41, designed to be applied to the support,
- a first finishing layer (311) in which the magnetizable particles (41) are dispersed, which is continuous and completely covers the lower layer (310), and
Magnetic particles 41 which are continuous and partly or completely covering the first finish layer 311 are also dispersed in the second finish layer 312,
(3). &Lt; / RTI &gt; 14. A method according to any one of claims 6 to 13, characterized in that the enamel layer (31)
A colored sublayer 310 in which magnetic particles 41 are dispersed and designed to be continuous and applied to a support, and
- at least one transparent finish layer (311) which is continuous and which partially or completely covers the sublayer (310), in which the magnetizable particles (41)
(3). &Lt; / RTI &gt; 18. The method according to any one of claims 14 to 17,
The lower layer 310 has a thickness of 5 to 30 [mu] m,
The finishing layer (s) 311, 312 have a thickness of 20 to 60 μm
Supplies (3). 14. The method according to any one of claims 6 to 13,
- The enamel layer (31)

A transparent or colored sublayer 310, which is continuous and free of magnetizable particles 41, designed to be applied to the support,

An interlayer 313 which is continuous and partially or completely covers the sublayer 310, and which is a magnetizable layer in which a coloring layer or magnetizable particles 41 are dispersed,
/ RTI &gt;
- the intermediate layer (313)

A first layer (321) of a continuous magnetic brightening agent in which magnetizable particles (41) are dispersed, and

A second layer 322 of uncolored, transparent, continuous polish completely covering the first layer 321 of the magnetic brightener,
Which is completely or partially covered by
Supplies (3). 20. The method of claim 19,

The lower layer 310 has a thickness of 5 to 30 占 퐉,

The intermediate layer 313 has a thickness of 20 to 60 mu m,

The layer 321 of the magnetic brightener has a thickness of 15 to 40 占 퐉,

The layer 322 of protective polish has a thickness of 10-20 [mu] m
Supplies (3). 21. An article (3) according to any one of claims 14 to 20, wherein the enamel layer (31) further comprises a silk screened or pad-printed discontinuous outer enamel layer (33). The article (3) of claim 21, wherein the outer enamel layer (33) comprises a circular filler, preferably stainless steel, copper, bronze or refractory steel beads. 23. An article according to any one of the preceding claims, wherein the support (2) is made of metal, glass or ceramic. 24. A device according to claim 23, characterized in that the support (2)

A single layer made of polished, brushed, micro-beaded, sanded or chemically treated aluminum or aluminum alloy, or cast aluminum, or polished, brushed, micro-bined stainless steel, or cast steel or aluminum Shaped metal support, or

Aluminum or austenitic stainless steel, or an outer stainless steel bottom casted aluminum, aluminum or aluminum alloy, either entirely or partially, from the exterior to the interior, or alternatively from ferritic stainless steel / aluminum / austenitic stainless steel or stainless steel / aluminum / copper / aluminum / austenitic stainless steel, A multi-layered metal support comprising a layer of aluminum alloy cap
. &Lt; / RTI &gt; 25. A method according to any one of claims 1 to 24, characterized in that the cooking utensil, the heating cover, or the heating blender bowl of a food or beverage production equipment, the tableware such as an iron base plate, a trivet, a radiator or a wood stove, Ning irons, towel rails or barbecue grills, boxes or tank inks. A method of applying a protective coating (3) to a support (2) of a heating article (1) having at least one enamel layer (31) with anisotropic particles (4)
Characterized in that it comprises the step of orienting said anisotropic particles (4) by physical or mechanical means in at least one region (5) of the enamel layer (31). 27. The method of claim 26,
a) providing a support (2);
b) applying at least one enamel composition dispersed in anisotropic particles comprising magnetizable particles (41) to one of the faces of the support (2) by micronisation;
c) applying a magnetic field to orient the magnetizable particles (41) by magnetization, the magnetizing step c) being performed during step b) of applying the enamel composition to the support or immediately after the application step b) In step; next
d) optionally, drying at a temperature of from ambient temperature to 150 캜; next
e) firing at a temperature of at least 500 &lt; 0 &gt; C
&Lt; / RTI &gt; 28. The process according to claim 27, wherein the applying step b)
- b1) forming an unfired sublayer (310) on one of the faces of the support (2) by micronisation of a transparent or colored enamel sublayer composition containing no magnetic particles; next
- b2) forming an uncured enamel finish layer (311) on the unfired sublayer (310) by milling of at least one finish enamel composition dispersed with magnetizable particles (41)
&Lt; / RTI &gt; Method according to claim 28, characterized in that step b) comprises, between the step b2) and the drying step d) or the calcining step e), on the uncured enamel finish layer 311, And b3) forming a second uncured enamel finish layer (312) by micronisation of at least one second finish enamel composition. 31. A method according to any one of claims 27 to 29, wherein after the drying step d) of the finish layers 311, 312, the enamel paste 33, which may or may not contain a round filler, is applied to the enamel finish layer 311 , 312). &Lt; / RTI &gt;

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