WO2018109619A1

WO2018109619A1 - Method for coating a base element for a household appliance component and household appliance component

Info

Publication number: WO2018109619A1
Application number: PCT/IB2017/057684
Authority: WO
Inventors: Jorge Alaman Aguilar; Raquel ALICANTE SANTIAGO; Maria Carmen Artal Lahoz; Carlos Gimeno Asin; Carlos Sanchez Somolinos
Original assignee: BSH Hausgeräte GmbH
Priority date: 2016-12-12
Filing date: 2017-12-06
Publication date: 2018-06-21
Also published as: EP3551779A1; CN110050087A

Abstract

The invention relates to a method for coating a base element (1) for a household appliance component. The method comprises at least the steps of depositing at least one silicon dioxide containing layer (2) onto at least one surface of the base element by combustion chemical vapour deposition and coating at least a portion of the at least one silicon dioxide layer using at least one fluorosilane. The invention further relates to a household appliance component comprising a coated base element (1) and to a household appliance comprising at least one household appliance component (1).

Description

METHOD FOR COATING A BASE ELEMENT FOR A HOUSEHOLD APPLIANCE COMPONENT AND HOUSEHOLD APPLIANCE

COMPONENT

The invention relates to a method for coating a base element for a household appliance component. The invention further relates to a household appliance component comprising a coated base element, and to a household appliance comprising said household appliance component.

Hydrophobic surfaces are a topic of increasing importance in household appliances and are required in many applications. A hydrophobic surface property is especially useful if water or other hydrophilic substances are required to be kept away from certain surface areas. Examples comprise water repellent surfaces on cooktops, easy to clean surfaces, anti-fingerprint properties, and the prevention of water from conductive or capacitive areas. However, currently known coatings either exhibit rather low degrees of hydrophobicity or require complex and expensive materials and coating methods to achieve sufficiently large contact angles.

It is the task of the present invention to provide a method for coating a base element for a household appliance component with an inexpensive hydrophobic coating. A further task of the invention consists in providing a household appliance component comprising a base element with an inexpensive hydrophobic coating. Still further, it is an object of the current invention to provide a household appliance comprising at least one household appliance component with an inexpensive hydrophobic coating.

These tasks are solved by a method for coating a base element for a household appliance component, a household appliance component, and a household appliance according to the independent claims. Advantageous developments of the invention are specified in the respective dependent claims, wherein advantageous developments of a specific aspect of the invention are to be regarded as advantageous developments of all other aspects of the invention and vice versa. A first aspect of the invention relates to a method for coating a base element for a household appliance component, comprising at least the steps of depositing at least one silicon dioxide containing layer onto at least one surface of the base element by combustion chemical vapour deposition and coating at least a portion of the at least one silicon dioxide layer using at least one fluorosilane. The method according to the invention allows the manufacturing of hydrophobic and even superhydrophobic surfaces through the combination of one or more silicon dioxide containing layers, which are deposited onto at least one surface of the base element by combustion chemical vapour deposition, and the subsequent coating of the silicon dioxide containing layer(s) using at least one fluorosilane as coating agent. The deposition by combustion chemical vapour deposition comprises the flame-pyrolytic deposition of (usually amorphous) silicon dioxide onto the base material to create a type of silicate coating. The surface to be treated is fed through a gas flame which is doped with a silicon-containing material, the so called pyrosil. The pyrosil burns in the flame and deposits as nanoparticles of silica on the surface in a firmly adhering coating. Due to the short flame-substrate interaction the material's surface temperature remains low. Thus, the first deposition step is suitable not only for base materials made of glass, ceramics, or metal but also for base materials made of plastics, wood, or other materials, so that any kind of household appliance component may be provided with a hydrophobic coating. Freshly deposited silica layers are highly reactive and thus serve as adhesion promoting layers for the following coating with fluorosilane. Adhesion can be further improved by application of additional silane-based adhesion promoters. Alternatively it may be provided that the layer consists of silicon oxide. Further, the present invention is based on the insight that the deposition of said one or more silicon dioxide containing layer(s) increases significantly the hydrophobicity, effectiveness, and controllability of the subsequent coating step with one or more fluorosilanes. It may be provided that the resulting layer consists of said one or more fluorosilanes. Alternatively, the resulting layer may comprise or consist of reaction products of the fluorosilane(s) and/or contain one or more further components. This allows for a fast and easy manufacturing of coatings with a higher degree of hydrophobicity than conventional coatings. Still further, the necessary base materials, i.e. the silicon-containing precursor material and the fluorosilane, are commercially available so that no expensive high performance materials are needed to achieve hydrophobic or even superhydrophobic surface properties with water contact angles of at least 150° or more. Both steps, i.e. the deposition and the coating step, may independently of each other generally be carried out once or multiple times to adjust the respective layer properties. Instead of the silicon dioxide contained layer, it might be also used a titanium contained based layer.

In an advantageous development of the invention it is provided that the base element is at least in portions cleaned and/or pretreated before depositing the at least one silicon dioxide containing layer. This improves the adherence of the deposited silicon oxide layer(s).

In a further advantageous development of the invention it is provided that the base element is cleaned by applying a cleaning medium and/or by ultrasonic cleaning and/or that the base element is pretreated by drying and/or ozone treatment. For example, the base material may be cleaned with water and a detergent or with an alcohol such as ethanol or isopropanol. Alternatively or additionally, the base material may be immersed in water and treated with ultrasounds for up to several minutes, e. g. 10 minutes. This may be repeated several times with optional intermediate rinsing steps. Alternatively or additionally, the base material may be dried by heating and/or by applying compressed air. Alternatively or additionally, an ozone treatment removes residuals from the surface and improves the adherence of the silicon dioxide containing layer(s) especially in the case of glass surfaces and other surfaces with free OH groups.

In a further advantageous development of the invention it is provided that an organosilane precursor, in particular tetraethoxysilane and/or tetramethylsilane, is used for depositing the at ntaining layer. Tetraethoxysilane has the chemical formula (I)

(I),

while tetramethylsilane has the chemical formula (II)

(II). During the combustion chemical vapor deposition step, the organic groups of the organosilane precursor are decomposed in the flame which leads to the formation of silanol R-Si(OH)₃. Subsequently, due to condensation reactions, the layer of siloxane (Si0₂) is created and adheres to the surface of the base material. This layer is highly hydrophilic and has a nanoporous structure.

In a further advantageous development of the invention it is provided that at least two layers of silicon dioxide are deposited on the base element. This means that 2, 3, 4, 5, 6, 7, 8, 9, 10 or more layers may be deposited onto the base material in order to achieve desired surface properties. Additionally or alternatively it is provided that the deposited silicon dioxide has an aggregated particle size of between 25 nm and 300 nm, for example 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 1 10 nm, 1 15 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 165 nm, 170 nm, 175 nm, 180 nm, 185 nm, 190 nm, 195 nm, 200 nm, 205 nm, 210 nm, 215 nm, 220 nm, 225 nm, 230 nm, 235 nm, 240 nm, 245 nm, 250 nm, 255 nm, 260 nm, 265 nm, 270 nm, 275 nm, 280 nm, 285 nm, 290 nm, 295 nm or 300 nm, and/or a roughness root mean squared value of between 40 nm and 100 nm, for example 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm as well as respective intermediate values. This allows for a precise adjustment of the hydrophobic properties and the resulting water contact angle and water sliding angle (roll-off angle) of the coated base material. For most applications, aggregated particle sizes between 100 nm and 200 nm and a roughness root mean squared value (R_q, R_RMs) between approximately 50 nm and 80 nm ensure a superhydrophobic effect with water contact angles of up to 160 ° and more and slinding angles of 5° or less.

In a further advantageous development of the invention it is provided that 1 H,1 H,2H,2H- perfluorooctyltriethoxysilane and/or trichloro(1 H,1 H,2H,2H-perfluorooctyl)silane is used as said fluorosilane. 1 H,1 H,2H,2H-perfluorooctyltriethoxysilane (PFOTESi) has the chemical formula (III)

-perfluorooctyl)silane (PFOTCSi) has the chemical formula (IV)

(IV). Both substances exhibit excellent hydrophobic properties in combination with the one or more silicon dioxide containing layer(s) due to their extreme low surface energy and the fast and easy reaction of their silane groups with hydroxyl groups of the silicon dioxide containing layer(s).

In a further advantageous development of the invention it is provided that the base element is coated with said at least one layer of fluorosilane by immersing at least a part of the base element one or multiple times for a predetermined time in a coating agent comprising said at least one fluorosilane. This so called dip coating step allows for a fast and easy coating of large base materials and of base materials with complex geometries. This step may of course be repeated once or multiple times with the same or different coating agents, allowing a series of thin layers to bulk up to a relatively thick final layer system. In a further advantageous development of the invention it is provided that a concentration of the at least one fluorosilane in the coating agent is between 0.5 vol% and 50 vol%, for example 0,5 vol%, 0,6 vol%, 0,7 vol%, 0,8 vol%, 0,9 vol%, 1 ,0 vol%, 2 vol%, 3 vol%, 4 vol%, 5 vol%, 6 vol%, 7 vol%, 8 vol%, 9 vol%, 10 vol%, 1 1 vol%, 12 vol%, 13 vol%, 14 vol%, 15 vol%, 16 vol%, 17 vol%, 18 vol%, 19 vol%, 20 vol%, 21 vol%, 22 vol%, 23 vol%, 24 vol%, 25 vol%, 26 vol%, 27 vol%, 28 vol%, 29 vol%, 30 vol%, 31 vol%, 32 vol%, 33 vol%, 34 vol%, 35 vol%, 36 vol%, 37 vol%, 38 vol%, 39 vol%, 40 vol%, 41 vol%, 42 vol%, 43 vol%, 44 vol%, 45 vol%, 46 vol%, 47 vol%, 48 vol%, 49 vol% or 50 vol%. This allows for a precise adjustment of the coating step and the resulting layer properties. Additionally or alternatively it is provided that the coating agent contains a solvent, in particular a fluorinated solvent, to dilute the fluorosilane as needed. The solvent may be or comprise for example methoxyperfluorobutane (HFE-7100). Additionally or alternatively it is provided that the predetermined time is between 10 seconds and 120 minutes, for example 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, 2 min, 4 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, 42 min, 44 min, 46 min, 48 min, 50 min, 52 min, 54 min, 56 min, 58 min, 60 min, 62 min, 64 min, 66 min, 68 min, 70 min, 72 min, 74 min, 76 min, 78 min, 80 min, 82 min, 84 min, 86 min, 88 min, 90 min, 92 min, 94 min, 96 min, 98 min, 100 min, 102 min, 104 min, 106 min, 108 min, 1 10 min, 1 12 min, 1 14 min, 1 16 min, 1 18 min or 120 min. This also allows for a precise adjustment of the coating step and the resulting layer properties.

In a further advantageous development of the invention it is provided that the base element is coated by chemical vapor deposition using said at least one fluorosilane. Thus, the base element, which is already provided with the deposited silicon dioxide containing layer(s), is exposed to one or more volatile fluorosilanes, which react and/or decompose on the substrate surface to produce the hydrophobic top layer. The fluorosilane may for example be hydrolyzed, which leads to the formation of silanols that are further condensated, thereby creating hydrogen bridges with the molecules of their same species and/or with OH groups of the silicon dioxide containing layer. In this way, the fluorosilane(s) decomposes and becomes covalently linked to the silicon dioxide containing base layer, thus providing the base material with durable hydrophobic surface characteristics.

In a further advantageous development of the invention it is provided that the at least one fluorosilane is exposed to water, in particular to humid air. This promotes the hydrolyzation of the fluorosilane and thus the condensation reactions with the silicon dioxide containing layer.

In a further advantageous development of the invention it is provided that the base element is post-treated after the coating step. This allows the removal of water, solvents, or unreacted compounds and/or the curing of unreacted compounds in the layers.

In a further advantageous development of the invention it is provided that the post-treatment comprises thermal treating of the coated base element at a predetermined temperature for a predetermined time and/or cleaning of the coated base element. The base material may for example be heated for up to 10 minutes to temperatures between 100 °C and 120 °C (1 10 °C) in order to evaporate water and to promote the condensation of unreacted silanol groups. The post-treatment may also comprise the cleaning of the coated base element, for example with acetone, to remove silanes or other impurities. A second aspect of the invention relates to a household appliance component comprising a base element, wherein at least one surface of the base element is at least partly coated with at least one combustion chemical vapor deposited silicon dioxide containing layer and at least one layer, which is manufactured by coating at least a portion of the at least one silicon dioxide layer using at least one fluorosilane. The household appliance component according to the invention thus comprises one or more hydrophobic or even superhydrophobic surfaces through the combination of one or more silicon dioxide containing layers, which are deposited onto at least one surface of the base element by combustion chemical vapour deposition, and the subsequent coating of the silicon dioxide containing layer(s) using at least one fluorosilane as coating agent. The deposition by combustion chemical vapour deposition comprises the flame-pyrolytic deposition of (usually amorphous) silicon dioxide onto the base material to create a type of silicate coating. The surface to be treated is fed through a gas flame which is doped with a silicon-containing material, the so called pyrosil. The pyrosil burns in the flame and deposits as nanoparticles of silica on the surface in a firmly adhering coating. Due to the short flame- substrate interaction the material's surface temperature remains low. Thus, any kind of base material, for example base materials made of glass, ceramics, or metal but also base materials made of plastics, wood, or other materials, may be provided with a hydrophobic coating. Freshly deposited silica layers are highly reactive and thus serve as adhesion promoting layers for the following coating with fluorosilane. Adhesion can be further improved by application of additional silane-based adhesion promoters. Alternatively it may be provided that the layer consists of silicon oxide. Further, the present invention is based on the insight that the deposition of said one or more silicon dioxide containing layer(s) increases significantly the hydrophobicity, effectiveness, and controllability of the subsequent coating step with one or more fluorosilanes. It may be provided that the resulting layer(s) consists of said one or more fluorosilanes. Alternatively, the resulting layer(s) may comprise or consist of reaction products of the fluorosilane(s) and/or contain one or more further components. This allows for a fast and easy manufacturing of coatings with a higher degree of hydrophobicity than conventional coatings. Still further, the necessary base materials, i.e. the silicon-containing precursor material and the fluorosilane, are commercially available so that no expensive high performance materials are needed to achieve hydrophobic or even superhydrophobic surface properties with water contact angles of at least 150° or more. The base material may generally comprise one or more silicon dioxide containing layers and one or more layers made from fluorosilane(s) to adjust the respective layer properties. In an advantageous embodiment of the invention it is provided that the at least one coated surface of the base element is superhydrophobic. According to the present invention, the term "hydrophobic" relates to coatings having water contact angles of 90° to 149° while the term "superhydrophobic" relates to coatings having water contact angles of more than 149° and preferably of 160° or more, for example 150 °, 151 °, 152 °, 153 °, 154 °, 155 °, 156 °, 157 °, 158 °, 159 °, 160 °, 161 °, 162 °, 163 °, 164 °, 165 °, 166 °, 167 °, 168 °, 169 °, 170 ° or more. This ensures surfaces that are extremely difficult to wet. A third aspect of the invention relates to a household appliance comprising at least one household appliance component with at least one base element, which is manufactured by a method according to the first aspect of the invention and/or at least one household appliance component according to the second aspect of the invention. The resulting features and their advantages can be gathered from the description of the first and second aspect of the invention. It is envisaged that the household appliance may be configured as a dishwasher, a dryer, a washing machine, a microwave oven, and/or a steam oven.

Further features of the invention are apparent from the claims, the figures and the description of figures. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations without departing from the scope of the invention. Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures and explained, but arise from and can be generated by separated feature combinations from the explained implementations. Implementations and feature combinations are also to be considered as disclosed, which thus do not have all of the features of an originally formulated independent claim. Moreover, implementations and feature combinations are to be considered as disclosed, in particular by the implementations set out above, which extend beyond or deviate from the feature combinations set out in the relations of the claims. The figures show in: Fig. 1 a schematic sectional view of a base element for a household appliance component, onto which a silicon dioxide layer is deposited by combustion chemical vapour deposition; and Fig. 2 a schematic sectional view of the base element, which is further coated using a fluorosilane.

Fig. 1 shows a schematic sectional view of a base element 1 made of glass for a household appliance component. For the preparation of a superhydrophobic surface, the following steps are carried out. First, the base element 1 is cleaned with water and soap, immersed in a water bath and charged with ultrasound for approximately 10 minutes. After rinsing the base material 1 , it is immersed once again in clean water and charged with ultrasound for further 10 minutes. The next cleaning step comprises immersing the base material 1 in ethanol and charging it with ultrasound for further 10 minutes. Finally, the base material 1 is dried with compressed air. Next, the base material 1 is treated with ozone to remove any organic residuals and to expose the OH groups of the glass material.

Subsequently, one or more silicon dioxide containing layer(s) are deposited onto the base element 1 by combustion chemical vapour deposition. This step creates an amorphous layer 2 of Si0₂ via a so called pyrosil process. The pyrosil is an organosilane precursor, which is injected into a flame (air+propane) in an amount sufficient to saturate the flame with the vapour of the organosilane. The pyrosil may for example be tetraethoxysilane (Si(OC₂H₅)₄) or tetramethylsilane (Si(CH₃)₄). Other organosilanes may be used as well as pyrosil/precursor.

The presently used system for depositing the pyrosil comprises an evaporator to create the organosilane vapour. For this purpose, air passes through the evaporator and is saturated by the organosilane vapour and mixed with propane for combustion. The parameters of the system are: temperature of organosilane in chamber is approximately 26

pyrosil flux 839 ml/min

pyrosil concentration 99 vol%

flux of air 100 l/min and

flux of propane 5.5 l/min. Good results are obtained if the surface of the base element 1 is placed between the internal and external part of the flame, i. e. in the oxidant part (not luminescent part) of the flame. The distance between the burner and the base element 1 is approximately 64 mm. The speed at which the base element 1 is moved along the flame is 100 mm/s. To increase the deposition of pyrosil on the surface, multiple passes using the same conditions are performed with breaks of approximately 15 seconds between different passes.

During the combustion, the organic groups of the organosilane are decomposed inside the flame, thereby forming silanol (R-Si(OH)₃) molecules.

The newly formed silanol melcules undergo condensation reactions with other silanol molecules and the OH groups of the glass surface of the base element 1 whereby the silanol molceules are covalently bonded to the surface of the base element 1. Consequently, a highly hydrophilic base layer 2 of siloxane (Si0₂) with a nanoporous structure is formed, which is firmly adhering to the base element 1. This step of depositing a silicon dioxide containing layer 2 may be repeated once or several times.

Due to the used system, the amount of deposited Si0₂ is directly related to the number of passes or repeats. However, it has to be stressed that the key factor is not necessarily the number of passes but the amount of deposited pyrosil/Si0₂. In other words, the number of passes and therefore the number of layers 2 depends on the subsequent purpose of the base element 1 , the desired properties of the layer(s) 2, and the system and parameters used to create the layer(s) 2. With the help of for example field emission scanning electron microscopy (FESEM), it is possible to measure the roughness of the surface of the layer 2 and to analyze the amount of deposited Si0₂ by evaluating the size and amount of the Si0₂ grains.

For 1 pass, Si0₂ particles of approximately 20 nm diameter and aggregations of 5 to 10 particles are formed. As long as more pyrosil is added in subsequent passes, a thicker layer 2 is deposited whereby the particles conglomerate to bigger particles. For 2 passes, the medium size of these aggregated particles is about 100 nm and for 4 passes around 200 nm. If different pyrosils are used for different passes, several different layers 2 can be deposited. Fig. 2 shows a schematic sectional view of the base element 1 , which is further coated using a fluorosilane. The fluorosilane (or fluorinated silane) is applied to reduce the surface tension of the surface. Two different fluorosilanes were deposited by using two different methods. Generally, both methods may be used alternatively or additionally, although the use of chemical vapour deposition (CVD) is usually preferred.

1) PFOTESi drop coating

The base material 1 was immersed in 1 H, 1 H,2H,2H-perfluorooctyltriethoxysilane (PFOTESi) containing solutions with different concentrations (1 vol%, 5 vol%, and 10 vol% in a fluorinated solvent (HFE-7100)) for different times (10 or 60 minutes). Thereby, one or more superhydrophobic top layer(s) 3 with different thicknesses is/are formed.

2) PFOTCSi CVD coating

The base material 2 is placed in a dissecator with 10 drops of trichloro(1 H, 1 H,2H,2H- perfluorooctyl)silane (PFOTCSi) during 1 hour under a vacuum of approximately 100 mbar. Due to the reaction of PFOTCSi with the humidity of the remaining atmosphere, the fluorosilane is hydrolyzed, thereby forming silanols that undergo subsequent condensation reactions with other silanol molecules and free OH groups of the Si0₂ layer 2. The fluorosilane is thus covalently linked to the amorphous Si0₂ layer 2 previously produced by the pyrosil reaction and forms a superhydrophobic top layer 3. The fluorosilane layer 3 is a thin layer that follows the topography of the pyrosil granulate layer 2.

As a final post-treatment, the coated base material 1 is heated up to approximately 1 10 °C for about 10 minutes to promote the evaporation of water and the condensation of unreacted silanol groups. Finally, the base material 1 is cleaned with acetone in order to eliminate any unreacted silanes, silanols, or other compounds.

Apart from FESEM, the topography of the resulting layers 2, 3 can be analyzed by atomic/scanning force microscopy (AFM) in order to determine the size of the Si0₂ particles and to determine the roughness of layer 2 or layer 3. In the following table 1 , the quadratic average roughness values RRMS of the coated base material 1 are shown. It can be seen that the roughness of the surface increases with the number of passes of pyrosil depositions. For 4 passes of pyrosil depositions, the roughness is about 5 times bigger compared to 1 pass. Table 1 : root mean squared roughness depending on the passes of pyrosil depositions

The roughness of the surface is related to the amount and size of the Si0₂ particles and thus to the water contact angle and the wettability of the surface. In summary, the use of the controlled pyrosil deposition(s) by varying the number of passes and thus the amount of pyrosil/Si0₂ and the size and surface concentration of grains and roughness not only improves the adherence of the subsequent layer 3 but also leads to highly hydrophobic, even superhydrophbic surface properties. This effect is maximized if 3-4 passes of pyrosil are deposited and/or if the aggregated particles size of the desposited Si0₂ is approximately 100 nm to 200 nm and if the quadratic average roughness value R_RMs is between approximately 50 nm and 80 nm.

With 1 pass of pyrosil, the water contact angle increases significantly although the surface is still "just" hydrophobic. With 2 passes, there is a second increase that makes the surface superhydrophobic, and with 3 to 4 passes, the water contact angle stabilizes at around 167 °. Further, the superhydrophobic surfaces made with 3 to 4 pyrosil passes show an extremely low sliding angle. In the following table 2, the results of the water contact angle and the sliding angle are shown in comparison with the number of pyrosil passes (directly linked with the amount of pyrosil).

Table 2

Ozone + 1 pass pyrosil 2 passes pyrosil + 3 passes 4 passes PFOTCSi + PFOTCsi PFOTCsi pyrosil + pyrosil +

PFOTCsi PFOTCsi

Water 1 09.81 ± 1 .01 1 35.73 ± 1 .46 1 62.53 ± 8.56 1 67.60 ± 1 66.32 ± contact 4.14 5.82

angle (°)

Sliding Water drop Water drop Inhomogeneous 3.1 1 .0

angle (°) adheres to adheres to surface with varying

surface surface angles It will be understood by those skilled in the art that while the present invention has been disclosed above with reference to preferred embodiments, various modifications, changes and additions can be made to the foregoing invention, without departing from the spirit and scope thereof. The parameter values used in the claims and the description for defining process and measurement conditions for the characterization of specific properties of the invention are also encompassed within the scope of deviations, for example due to measurement errors, system errors, weighing errors, DIN tolerances and the like.

LIST OF REFERENCES base element

layer

Claims

A method for coating a base element (1 ) for a household appliance component, comprising at least the steps of

depositing at least one silicon dioxide containing layer (2) onto at least one surface of the base element by combustion chemical vapour deposition; and

coating at least a portion of the at least one silicon dioxide layer using at least one fluorosilane.

The method according to claim 1 , wherein the base element (1 ) is at least in portions cleaned and/or pretreated before depositing the at least one silicon dioxide containing layer (2).

The method according to claim 2, wherein the base element (1 ) is cleaned by applying a cleaning medium and/or by ultrasonic cleaning and/or wherein the base element (1 ) is pretreated by drying and/or ozone treatment.

The method according to any one of claims 1 to 3, wherein an organosilane precursor, in particular tetraethoxysilane and/or tetramethylsilane, is used for depositing the at least one silicon dioxide containing layer (2).

The method according to any one of claims 1 to 4, wherein at least two layers (2) of silicon dioxide are deposited on the base element (1 ) and/or wherein the deposited silicon dioxide has an aggregated particle size of between 25 nm and 300 nm and/or a roughness root mean squared value of between 40 nm and 100 nm.

The method according to any one of claims 1 to 5, wherein 1 H,1 H,2H,2H- perfluorooctyltriethoxysilane and/or trichloro(1 H,1 H,2H,2H-perfluorooctyl)silane is used as said fluorosilane.

The method according to any one of claims 1 to 6, wherein the base element (1 ) is coated with at least one layer (3) of fluorosilane by immersing at least a part of the base element (1) one or multiple times for a predetermined time in a coating agent comprising said at least one fluorosilane. The method according to claim 7, wherein a concentration of the at least one fluorosilane in the coating agent is between 0.5 vol% and 50 vol% and/or wherein the coating agent contains a solvent, in particular a fluorinated solvent, and/or wherein the predetermined time is between 10 seconds and 120 minutes.

The method according to any one of claims 1 to 8, wherein the base element (1 ) is coated by chemical vapor deposition using said at least one fluorosilane.

The method according to any one of claims 1 to 9, wherein said at least one fluorosilane is exposed to water, in particular to humid air.

The method according to any one of claims 1 to 10, wherein the base element (1) is post- treated after the coating step.

The method according to claim 7, wherein the post-treatment comprises thermal treating of the coated base element (1) at a predetermined temperature for a predetermined time and/or cleaning of the coated base element (1).

A household appliance component comprising a base element (1 ), wherein at least one surface of the base element (1 ) is at least partly coated with at least one combustion chemical vapor deposited silicon dioxide containing layer (2) and at least one layer (3), which is manufactured by coating at least a portion of the at least one silicon dioxide layer using at least one fluorosilane.

The household appliance component according to claim 13, wherein the at least one coated surface of the base element (1) is superhydrophobic.

A household appliance comprising at least a household appliance component with at least one base element (1), which is manufactured by a method according to any one of claims 1 to 12 and/or at least one household appliance component according to claim 13 or 14.