ES2589478A1 - Domestic appliance component comprising a base element with a functional coating (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The invention relates to a domestic appliance component (4), which comprises a base element (2), wherein at least one surface of the base element (2) is partially or completely covered with a functional covering (5) comprising at least one hybrid organic-inorganic compound. Also, the invention relates to a method for coating a domestic appliance component (4), a household appliance comprising at least one domestic appliance component (4), and the use of at least one hybrid organic-inorganic compound for partially or completely covering a surface of a base element (2) of a household appliance component (4). (Machine-translation by Google Translate, not legally binding)

Description

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COMPONENT OF DOMESTIC APPLIANCE THAT INCLUDES A BASE ELEMENT WITH A FUNCTIONAL COATING

DESCRIPTION

The invention refers to a domestic appliance component, which comprises a base element, where at least one surface of the base element is partially or completely covered with a functional coating. Also, the invention refers to a method for coating a domestic appliance component, and a domestic appliance.

The use of different metal alloys as raw materials in domestic appliances can lead to increased problems related to corrosion during the life of the appliances. Particularly washing machines and dishwashing machines comprise many surfaces that are in direct contact with water with and with chemical products. In those cases where both the properties of steel and corrosion resistance are required, stainless steel is usually used, which does not generally corrode with water, unlike normal steel. However, most stainless steel varieties are not totally resistant to corrosion in environments with low oxygen content, high salinity, or poor air circulation. In order to avoid the use of completely corrosion-resistant and very expensive materials, functional coatings are normally applied to critical areas of household appliances components, for example, in places where water and chemical products can remain after one cycle. of washing a washing machine or a dishwasher.

Different approaches have been developed to achieve better protection against corrosion in metals. These approaches depend on the type of metal (for example, steel, stainless steel, zinc, etc.), and the environment (for example, inside or outside) for which the domestic appliance is intended. In general, there are two methods for the protection of metals against corrosion, which are active and passive protection. In the case of domestic appliance components, passive corrosion protection is usually the simplest approach, since it allows the reduction of production costs as well! as a simpler technological implementation. In passive corrosion protection, corrosion is avoided or, at least, delayed, shielding the metal surface against the corrosive agent by means of a functional coating. By

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therefore, functional coatings should not present pores, be resistant to external mechanical stress, and adhere firmly to the surface of the respective metal. The thickness of the functional coatings depends largely on the process and the composition of the substances used. Inorganic functional coatings are usually composed of layers of oxide or phosphate with a thickness between 1 pm and 20 pm. The metallic functional coatings can be applied by different methods and can have a thickness that is in the range of 1 pm to 20 mm. Nonmetallic functional coatings, such as silicate or cement coatings, usually have a thickness in the range of 350 pm to 20 mm. Protective organic functional coatings, such as bitumen, rubber, or plastic coatings, as well as paints, can generally have a thickness in the range of 80 pm to 20 mm.

However, the functional coatings known at present have several disadvantages because they are very expensive, have a fairly high thickness, or cannot resist high pH values (pH> 9) or a humid atmosphere during the useful life of the respective domestic appliance.

The present invention solves the technical problem of providing a domestic appliance component with an economical functional coating for the protection of the domestic appliance component against moisture, aggressive chemical environments, and corrosion. Another technical problem that solves the invention is to provide a method for coating a domestic appliance component with a functional coating that can be economically applied and that protects the domestic appliance component from moisture, aggressive chemical environments, and corrosion. . In addition, another technical problem that solves the present invention is to provide a domestic appliance comprising at least one domestic appliance component with a high corrosion resistance.

These technical problems are solved by a domestic appliance component, a method for coating a domestic appliance component, a domestic appliance, and a utilization according to the independent claims. Advantageous developments of the invention are specified in the respective dependent claims, wherein the advantageous developments of the domestic appliance component are to be considered advantageous developments of the domestic appliance method and method, and vice versa.

A first aspect of the invention refers to a domestic appliance component,

which comprises a base element, where at least one surface of the base element is

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partially or completely coated with a functional coating, where the coating comprises at least one organic-inorganic hybrid compound. Organic-inorganic hybrid materials can be defined in general as molecular compounds or nanocomposites with organic and inorganic components, closely mixed, where at least one of the component domains has a dimension ranging from several A to several nanometers. Consequently, the properties of hybrid materials are not only the sum of the individual contributions of both phases, but the role of their interior interfaces may be predominant. The nature of the interface has been used to divide these materials broadly into two different classes. In class I materials, organic and inorganic components are embedded, and hydrogen bonds, van der Waals and / or ionic provide cohesion to the compound. In class II materials, the two phases are linked together through strong covalent or ionic-covalent bonds. Organic-inorganic hybrid compounds can be tailor-made for the respective base element, and show excellent protection against corrosion in highly corrosive and humid environments. In addition, the functional coating comprising the organic-inorganic hybrid compound may have a very small thickness to achieve effective and lasting corrosion protection. Thanks to this reduced thickness, the coating does not hamper the utilization and integration of the domestic appliance component in a respective domestic appliance. Also, only a very small amount of the organic-organic compound (s) is necessary, and can be easily applied to the base element, which effectively reduces production costs. In general, the base element coating may be composed of one or more organic-inorganic hybrid compounds. The coating may also comprise one or more additional components. The surface of the base element may be only partially coated, although it is also possible that the entire surface of the base element is coated. Also, the base element may comprise different coatings on different surface areas, where at least one of the coatings comprises or is composed of at least one organic-inorganic hybrid compound.

In an advantageous development of the invention, it is envisioned that the base element comprises or is composed of a metal alloy, in particular a stainless steel alloy. Thanks to the excellent corrosion protection provided by the coating, the base element can comprise or be composed of a cheaper metal alloy with a relatively low corrosion resistance, thus reducing! the production costs and / or the weight of the household appliance component.

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In another advantageous development of the invention, the coating is expected to have a thickness of less than 20 pm, in particular, less than 10 pm. The coating may, for example, have a maximum thickness of 20 pm, 19 pm, 18 pm, 17 pm, 16 pm, 15 pm, 14 pm, 13 pm, 12 pm, 11 pm, 10 pm, 9 pm, 8 pm , 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, or less. Thus, the coating has a thickness considerably below the thickness of normally used paints, and greatly reduces the utilization of coating material. Reduced thicknesses are also advantageous to meet strict tolerances.

In another advantageous development of the invention, the coating is expected to comprise silica nanoparticles. The silica nanoparticles, which can be precipitated within the coating, improve the mechanical properties of the coating, so that the coating can be applied as a non-porous thin layer.

In another advantageous development of the invention, it is envisioned that the domestic appliance component is configured as a cladding or wall element of a domestic appliance. This makes it possible to prevent corrosion on interior and / or exterior walls of domestic appliance surfaces.

A second aspect of the invention refers to a method for coating a domestic appliance component, where at least one surface of a base element of the domestic appliance component is partially or completely coated with at least one organic-inorganic hybrid compound. Organic-inorganic hybrid materials can be defined in general as molecular compounds or nanocomposites with organic and inorganic components, closely mixed, where at least one of the component domains has a dimension ranging from several A to several nanometers. Consequently, the properties of hybrid materials are not only the sum of the individual contributions of both phases, but the role of their interior interfaces may be predominant. The nature of the interface has been used to divide these materials broadly into two different classes. In class I materials, organic and inorganic components are embedded, and hydrogen bonds, van der Waals and / or ionic provide cohesion to the compound. In class II materials, the two phases are linked together through strong covalent or ionicocovalent bonds. Organic-inorganic hybrid compounds can be tailor-made for the respective base element, and show excellent protection against corrosion in highly corrosive and humid environments. In addition, the functional coating comprising the organic-inorganic hybrid compound may have a very small thickness.

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to achieve effective and lasting corrosion protection. Thanks to this reduced thickness, the coating does not hamper the utilization and integration of the domestic appliance component in a respective domestic appliance. Also, only a very small amount of the organic-organic compound (s) is necessary, and can be easily applied to the base element, which effectively reduces production costs. In general, the base element coating may be composed of one or more organic-inorganic hybrid compounds. The coating may also comprise one or more additional components. The surface of the base element may be only partially coated, although it is also possible that the entire surface of the base element is coated. Also, the base element may comprise different coatings on different surface areas, where at least one of the coatings comprises or is composed of at least one organo-inorganic hybrid compound.

In an advantageous development of the invention, it is envisioned that the organo-inorganic hybrid compound is applied by spray coating on the base element. In other words, it is envisaged that at least one section of the base element is partially or completely coated with one or more organic-inorganic hybrid compounds by means of a spray coating process. Coatings generated by spray coating have excellent mechanical and chemical properties and can be easily applied to all base materials and shapes commonly used. In addition, spray coating makes it possible for production costs to be low.

In another advantageous development of the invention, it is anticipated that the organo-inorganic hybrid compound employed will be synthesized through a sol-gel process using at least one inorganic component and at least one organic component as precursors. A sol-gel process is a method to produce solid materials from small molecules. The process involves the conversion of precursor monomers into a colloidal solution (sol) that acts as the precursor for a gel of discrete particles or crosslinked polymers. Organic-inorganic hybrid compounds that are synthesized through a sol-gel process form hard coatings with excellent corrosion protection, and present the advantages of both organic and inorganic precursors. In addition to this anti-corrosion property, several possibilities are opened for the creation of additional functionalities tailored by combining different organic and inorganic precursors.

In another advantageous development of the invention, it is envisioned that the inorganic component for the sol-gel process is selected from one or more of the colloidal silica, in particular, silica nanoparticles, and the tetraalkylortosilicate, in particular, the tetramethylortosilicate (TMOS ) and / or tetraethylorthosilicate (TEOS). The tailored selection of the chemical groups of the inorganic precursors allows to optimize the chemical resistance of the resulting organic-inorganic hybrid compound required for the functionality of the domestic appliance component in an aqueous and chemically aggressive environment.

In another advantageous development of the invention, it is envisioned that the organic component for the sol-gel process is selected from one or more of 3-glycidoxypropyltrimethoxysilane (GPTMS), methacryloxypropyltrimethoxysilane (MPTMS), vinyltriethoxysilane (VTES), methyltriethoxysilane (MTES), and

ROi

\

ROI ...... Yes-

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RO

H

-C-

H

l_ _l x

HO

-N ------ C ------ O-

H

C

H

! _ _iy

OH

-O ------ C ------- N-

H C H

Jz

OR

-If I OR

V

OR

15 where "x", "y" and "z" are integers independently selected from 1 to 30, and where "R" are independently selected from the group consisting of hydrogen and substituted or unsubstituted C1-C20 alkyl. The tailored selection of the chemical groups of the organic precursors allows to optimize the chemical resistance of the resulting organic-inorganic hybrid compound required for the functionality of the domestic appliance component in an aqueous and chemically aggressive environment.

A third aspect of the invention refers to a domestic appliance, which comprises at least one domestic appliance component according to the first aspect of the invention and / or at least one domestic appliance component that is partially or completely covered by a method according to the second aspect of the invention. Thus, the domestic appliance according to the invention comprises one or more economic functional coatings to protect the domestic appliance from moisture, aggressive chemical environments, and corrosion. Other features and their advantages can be extracted from the description of the first and second aspects of the invention.

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In another development of the invention, it is envisioned that the domestic appliance is configured as a washing machine or dishwasher. This allows the use of cheaper stainless steel raw materials in the domestic appliance, since the appearance of corrosion problems is not expected during the useful life of the appliance, although washing machines and dishwashing machines are in direct contact with water and aggressive chemical products.

A fourth aspect of the invention refers to the use of at least one organic-inorganic hybrid compound to partially or completely cover a surface of a base element of a domestic appliance component. The characteristics and their resulting advantages can be extracted from the description of the first, the second, and the third aspect of the invention.

Other features of the invention are drawn from the claims and the following embodiments. The features and combinations of features mentioned above in the description, as! as the characteristics and combinations of characteristics mentioned below in the embodiments, they are usable not only in the combination indicated in each case, but also in other combinations without abandoning the scope of the invention. Therefore, variations of the invention are also possible that are not explicitly shown and described in the embodiments but which, however, can be formulated through different combinations of features separate from the described embodiments. Variations and combinations of features that do not contain all the features of an independent revindication originally formulated are also possible. Next, the embodiments of the invention are described in more detail with reference to the schematic drawings. Here, they show:

Fig. 1 a conventional uncoated domestic appliance component; Y

Fig. 2 a household appliance component according to the invention, which comprises

a base element with a coating made of an organic-inorganic hybrid compound.

Figure 1 shows a conventional household appliance component 1, which comprises a base element 2 without any coating. The base element 2 is made of stainless steel, and is in contact with water 3. The rust is composed of different iron oxides and hydroxides, which are formed by the redox reaction of iron and oxygen in the presence of moisture water 3 from air. If there is no coating, or if the permeability of a given coating (not shown) is high, the

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Water molecules will come into direct contact with the base element 2 and several electrochemical reactions will take place, thus causing corrosion of the base element 2. The key reaction is the reduction of oxygen:

O2 + 4e- + 2H2O ^ 4OH-

The supply of electrons for the previous reaction is the oxidation of iron that can be described as follows:

Fe ^ Fe2 + + 2e-

The following redox reaction also occurs in the presence of water, and is essential for the formation of the rust:

4Fe2 + + O2 ^ 4Fe3 + + 2O2-

These reactions create a current that can be measured within a range of several seconds after contact with water. Corrosion weakens the base element 2 by making its metal structure fragile and brittle.

Figure 2 shows a domestic appliance component 4 according to the invention, which comprises a base element 2 with a coating 5 made of an organic-inorganic hybrid compound, and composed, in particular, of a stainless steel alloy. The organic-inorganic hybrid compound has been produced through a sol-gel process by reticulation of two types of organic and inorganic precursors. Additionally, silica nanoparticles were precipitated into the coating 5 to form a very thin non-porous layer. The customized selection of the chemical groups of organic polymers allows to achieve excellent chemical resistance to protect stainless steel from chromium in an aggressive aqueous environment. The organic precursor may have the formula,

RO.

\

............Yes-

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RO

H

-C

H

H O

N ------ C

l_ _l x

OR

H OH

C ------ O ------- C ------- N

image 1

H

C

H

OR

r

-Yes.......

V

OR

_ z

where "x", "y" and "z" are integers independently selected between 1 and 30, and where "R" are independently selected from the group consisting of

hydrogen and substituted or unsubstituted C1-C20 alkyl. Additionally or alternatively, the organic precursor may have the formula

image2

The inorganic precursor can be, for example, colloidal silica and / or a tetraalkylortosilicate. The coating 5 has a thickness of 10 pm or less, so that only a small amount of material is needed to protect the domestic appliance component 4.

To compare the corrosion protection of different coatings on chrome stainless steel, the cyclic voltameter curves based on "a percentage of protection" achieved by the coatings have been measured, although there are several 10 qualitative methods to evaluate the anti-corrosion properties of one layer, the cyclic voltameter has been chosen to provide fast and accurate results.The corrosion protection of various functional coatings has been calculated through the formula

Corrosion protection (%) =

J (reference) - J (coating) J (reference)

* 100

15 The coatings have been evaluated after supporting an aging test of more than 50 washing cycles with detergent (pH> 9 and T = 70 ° C). The quantification of the potential with the maximum current density shows that excellent corrosion protection is achieved by sol-gel coatings based on organic-inorganic hybrid compounds, providing a corrosion protection of 110% or more compared with 20 With the reference coating.

Those skilled in the art will understand that, while the present invention has been set forth with reference to the preferred embodiments, various modifications, changes and additions to the previous invention may be made without abandoning the spirit and scope thereof. The values of the parameters used in the 25 claims and in the description to define the process and measurement conditions to characterize the specific properties of the invention are also included.

within the framework of deviations, for example, as a result of measurement errors, system errors, weight errors, DIN tolerances, and the like.

LIST OF REFERENCE SLOTS

1 Conventional household appliance component

2 Base element

3 Water

4 Domestic appliance component according to the invention

5 Coating

Claims (13)

5 10 fifteen twenty 25 30 1. Domestic appliance component (4), which comprises a base element (2), where at least one surface of the base element (2) is partially or completely covered with a functional coating (5), characterized in that the coating ( 5) comprises at least one organic-inorganic hybrid compound. 2. Domestic appliance component (4) according to claim 1, wherein the base element (2) comprises or is composed of a metal alloy, in particular a stainless steel alloy. 3. Domestic appliance component (4) according to claim 1 or 2, wherein the coating (5) is less than 20 pm thick, in particular less than 10 pm. 4. Domestic appliance component (4) according to any of claims 1 to 3, where the coating (5) comprises silica nanoparticles. 5. Domestic appliance component (4) according to any of claims 1 to 4, which is configured as a lining or wall element of a domestic appliance. 6. Method for coating a domestic appliance component (4), characterized in that at least one surface of a base element (2) of the domestic appliance component (4) is partially or completely coated with at least one organic-inorganic hybrid compound . 7. Method according to claim 6, wherein the organic-inorganic hybrid compound is applied by spray coating on the base element (2). 8. Method according to claim 6 or 7, wherein the organo-inorganic hybrid compound used is synthesized through a sol-gel process using at least one inorganic component and at least one organic component as precursors. 10 fifteen twenty 9. Method according to claim 8, wherein the inorganic component for the sol-gel process is selected from one or more of the colloidal silica, in particular, silica nanoparticles, and tetraalkylortosilicate, in particular, tetramethylortosilicate (TMOS) and / or tetraethylorthosilicate (TEOS). 10. Method according to claim 8 or 9, wherein the organic component for the sol-gel process is selected from one or more of the 3-glycidoxypropyltrimethoxysilane (GPTMS), methacryloxypropyltrimethoxysilane (MPTMS), vinyltriethoxysilane (VTES), methyltriethoxysilane MTES), and RO „ \ ROI ......... RO H -C- H L Jx HO N ------ C OR

 H

   OR

 H

 C-

 —OR— —C— —N

 H

Jy H C H OR / -If I OR V OR z where "x", "y" and "z" are integers independently selected from 1 to 30, and where "R" are independently selected from the group consisting of hydrogen and substituted or unsubstituted C1-C20 alkyl. 11. Domestic appliance, which comprises at least one domestic appliance component (4) according to any one of claims 1 to 5 and / or at least one domestic appliance component (4) which is partially or completely coated by a method according to any one of claims 6 to 10. 12. Domestic appliance according to claim 11, which is configured as a washing machine or as a dishwasher. 13. Use of at least one organic-inorganic hybrid compound to partially or completely cover a surface of a base element (2) of a domestic appliance component (4).