WO2013092422A1

WO2013092422A1 - Component of a domestic appliance with a coating

Info

Publication number: WO2013092422A1
Application number: PCT/EP2012/075572
Authority: WO
Inventors: Andreas Bischof; Marcus Heyer-Wevers
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2011-12-20
Filing date: 2012-12-14
Publication date: 2013-06-27
Also published as: EP2794975A1; EP2794975B1; DE102011089114A1

Abstract

A component (1) of a domestic appliance, which component (1) is wetted by a liquid, is provided with an at least hydrophobically acting coating on the surface thereof which comes into contact with the liquid. Said at least hydrophobically acting coating (6) is configured as a liquid boundary layer which consists of a substrate (9) and a boundary liquid (10) which is incorporated therein. Here, with respect to the liquid which wets the component (1), the boundary liquid (10) has a sliding layer (11) which repels the liquid.

Description

Component of a household appliance with a coating

The invention relates to a component of a household appliance which is wetted by a liquid and is provided on its surface which comes into contact with the liquid with a coating which is at least hydrophobic.

Hydrophobic surfaces are known from nature, in which they are particularly adapted to plants. The purging of liquids from these surfaces is commonly referred to as a "lotus effect." For example, hydrophobicity is achieved on leaf surfaces by being composed of natural wax, which is in a particular waxy scale structure.

It is already being attempted to utilize this effect for industrially produced components which come into contact with liquids, the correspondingly wetted surfaces being provided with coatings, which are preferably produced from fluoropolymers, silicone resins, polysiloxanes or polysilanes. Care must always be taken to ensure that the liquid, which may contain dust, oily dirt or aggressive components, can flow off due to an inclined arrangement of the surface. If liquid residues accumulate on the surface and last for a longer time at these locations, there is a risk that the coating will be destroyed despite the hydrophobic surface coating. Then, the liquid can come into contact with the surface of the corresponding component, so that there form residues or corrosion occurs on the component. In addition to a hydrophobing of the surface, depending on the application, its oleophobization is generally also desired, and the corresponding coating is then also suitable for preventing oils and fats from adhering to the surface. Depending on their type and viscosity, these oils, fats and oily or fatty emulsions will bead on the oleophobic surface.

Such an oleophobic surface coating is described in the scientific article "Bio-inspired self-repairing slippery surfaces with pressure-stable omniphobicity" published in the journal "Nature", Volume: 477, Pages: 443-447 of 22 September 201 1 , A component of a household appliance with a hydrophobic coating circumscribed in the preamble of the independent claim genus is known from the document DE 10 2008 055 093 A1. It is a screen to be used inside a duct to clean the process air of a tumble dryer or the exhaust air of a vacuum cleaner. In addition, this relatively fine-mesh sieve can also be used for cleaning a liquid process medium in a dishwasher or a washing machine. In all these applications, in addition to moisture, the screen is also exposed to lint, dirt particles and, in some cases, detergent residues that may stick to the mesh of the screen, provided that it only consists of a corresponding base material, such as wire or plastic. Since these dirt components, lint and detergent residues very persistently adhere to the screen, it is intended to provide the Siebgrundmaterial with a hydrophobic coating. It can thereby be achieved that, for example, when using the sieve in a tumble dryer, the lint can be easily removed from the sieve by means of a sieve cleaning device having a spray head. The hydrophobic coating should be designed as nanolack, which consists of mixed under a coating base nano-ceramic particles, said nanolack cures after being applied to the Siebgrundmaterial by the action of a temperature. It is an object of the present invention to provide a surface coating for a wetted with a liquid component of a household appliance, which is universally applicable to household appliances and stably adhered to the surface of the corresponding component of the household appliance. Furthermore, the surface coating should be insensitive to mechanical damage and permanently ensure drainage of the surface flowing past, mostly heavily contaminated liquid.

This object is achieved on the basis of the preamble of the independent claim by the connection with its characterizing features. The subsequent dependent claims each represent advantageous developments of the invention.

According to the characterizing part of the independent claim, the at least hydrophobic coating should be formed as a liquid boundary layer, wherein it consists of a substrate with a boundary liquid embedded therein and this boundary liquid forms a repellent lubricating layer with respect to the liquid wetting the component. Fluid-carrying components in household appliances are often not completely emptied for a long period of time or can not dry. There are also surfaces of components where residues of dissolved or suspended components, such. As lime, lint, filter residues, etc. deposit. Finally, organic residues in the liquid can be a breeding ground for germination and the formation of biofilms. This is due to interactions of the liquid or its components with the surface.

By the invention, the surfaces of components of the household appliances, where these problems occur, be provided with a technical surface, which causes the residue-free emptying or discharge of such liquids and their undissolved constituents. This can be reliably prevented that form deposits or biofilms on the corresponding surface, and it is achieved that liquid operating media for household appliances are used efficiently and completely in the respective work process. In this case, a self-repairing, slippery surface is formed by means of the embedded in a substrate boundary liquid, which acts both hydrophobic and oleophobic.

At the liquid boundary layer, which acts both hydrophobic and oleophobic, no residues from the passing liquid can adhere. The liquid boundary layer of the boundary liquid is a perfect structure for immiscible substances (liquids). This coating, which is formed from the substrate and the stored boundary liquid, is also not impaired in its effect by passing by-passing surfactant-containing alkalis. In addition, components that are abrasive in the fluid can not damage the surface coating. Therefore, such a surface coating is particularly suitable for components of household appliances that are wetted by liquids.

In contrast, the hydrophobic coating according to DE 10 2008 055 093 A1 is designed as a nano-lacquer which is applied to the corresponding sieve base material with a thickness of 1-10 μm. As already stated, this nano-lacquer should consist of a lacquer base, into which nanoceramic particles are mixed. The nanolack should harden after application to the sieve base material by the action of temperature, so form a solid surface coating. With such surface coatings, on which surfactant-containing alkalis or liquids with abrasive constituents are guided, experience has shown that they are not permanent and lose their effect, in particular in the case of mechanical damage.

In a development of the invention, the substrate should have a nanoporous structure. The boundary liquid adheres stably to the substrate having the nanoporous structure according to the principle of wick lubrication, so that the boundary liquid does not mix with the outflowing liquid. On the surface of the boundary liquid, a sliding layer is formed so that the liquid impinging on this sliding layer easily expands at a certain inclination angle of the corresponding surface without sticking. The particles contained in the liquid can not be deposited on the sliding layer.

The substrate may also be formed as a porous network, in particular in the form of a braid, in which the boundary liquid is embedded. It is also possible to produce the substrate by etching, laser structuring, corroding, plasma processing or structured growth on the surface of the component. The liquid boundary layer should act both hydrophobic and oleophobic, so that in addition to water, other liquids can come into contact with the coating and do not adhere to this surface.

In household appliances, the surface coating according to the invention can be used in all liquid-carrying components to improve residue-free emptying. When constructing components, it must be taken into account that a certain angle of inclination must be maintained in order to ensure drainage of the liquid. Typically, in household appliances in the running liquids to water and surfactant-containing rinses or wash liquors with and without solid ingredients such as lime, zeolites, fluff, food particles, etc.

For example, silicone oils, ionic liquids or polar or nonpolar organic solvents can be selected as boundary fluid. The choice of the liquid pairing must be exactly adapted to the purpose and possibly requires experimental measurement dates. The substrate must be chosen so that the repulsive boundary liquid can be stably embedded in the near-surface network.

Particularly advantageous are applications of surface coating in components that may absorb lime-containing water and thus tend to calcify. This may, for example, be a water tank of a steam iron, a water tank of a kettle or a heating bag of a washing machine. The use of the surface coating according to the invention prevents lime deposits from precipitating in these components.

Furthermore, the coating can advantageously be provided in dishwashing dishes of dishwashers or washing machines, in which residues of dishwashing or washing agents are always deposited on conventionally formed surfaces. This problem can be avoided if the surface coming into contact with the rinsing or washing agent is designed in accordance with the invention, so that these means are completely rinsed out of the dispensing tray via the water supplied to the household appliance.

In addition, there are further possibilities of using this surface coating on components of household appliances:

For example, in a washing machine, the insides of a suds container and in a condensation dryer the heat exchanger serving as a heat sink or the condensate container may be provided with a corresponding coating. In household appliances in which liquids are passed through pumps and a hose or pipeline system, the interior of the hoses or pipes or also the interior of the corresponding pump components such as pump housing and the wheels can be coated according to the invention. In refrigerators can be avoided by the coating according to the invention that condensation condenses on the cooling surfaces and permanently leads to their icing.

Particular advantages for the use of this surface coating according to the invention is primarily the avoidance of biofilm formation, which is hygiene-relevant. Furthermore, the deposition of lime, which leads to a reduction in the life of the corresponding household appliance, of lint or detergent components that the Function of the household appliance influence, be prevented. Otherwise, in all liquid-carrying systems, over the lifetime of such deposits can occur, which close in the worst case openings or piping systems. This can lead to the failure of the household appliance or performance losses. The coating according to the invention can significantly reduce or completely prevent these malfunctions and performance losses with appropriate use in household appliances.

Another advantage is the self-cleaning property of the surface, as it is constantly freed of residues by running-off liquid. Due to the achieved self-cleaning effects in household appliances can be largely dispensed with prescribed manual equipment cleaning cycles.

The invention is not limited to the specified combination of the features of the independent patent claim and the claims dependent thereon. In addition, there are further possibilities for combining individual features, in particular if they result from the patent claims, the following description of an exemplary embodiment or directly from the drawing. In addition, reference to the drawings by the use of reference numerals is not intended to limit the scope of the claims to the illustrated embodiments.

Incidentally, further features of the invention emerge from the following description of a preferred exemplary embodiment and from the attached drawing referred to therein, in which this exemplary embodiment is shown in simplified form. Show it:

FIG. 1 shows a schematic representation of a dispenser tray provided with a surface coating, which is preferably used for a washing machine or dishwasher,

2 shows an enlarged detail according to view II in Figure 1 and

Figure 3 is a schematic representation of a conventionally designed Einspülschale. In the figure 1, the dispenser 1, the side walls 2 and 3 and a sloping bottom 4. The dispenser 1 is provided with an outlet opening 5 which is formed at the end of the inclined bottom 4 of this together with the side wall 3. Furthermore, the bottom 4 is provided over its entire surface facing the interior of the dispensing dish 1 with a coating 6 which is both hydrophobic and oleophobic. The interior of the dispensing dish is usually filled with a prescribed amount of a washing or rinsing agent, and after the start of the washing or rinsing process, as shown symbolically by an arrow, water is supplied via a water inlet 7. This water then rinses the washing or rinsing agent from the dispenser 1 and this mixture of water and Waschbzw. Rinsing agent then enters for the outlet opening 5, as shown with a further arrow, as Laugenstrom 8 in the interior of a non-illustrated tub or the interior of a dishwasher, also not shown. It can be seen in detail from FIG. 2 that the bottom 4 consists of a wall 8 made of stainless steel, a substrate consisting of a porous, mesh-like network 9, which receives a boundary liquid 10, being formed on this wall 8. This embedded in the substrate 9 boundary liquid 10 forms on the surface facing away from the wall 8 a sliding layer 1 1, which avoids that present in the dispenser 1 washing or rinsing agent or residues of water to connect to the surface of the wall 8 and adhere to this.

In contrast, FIG. 3 shows a conventional embodiment of an induction bowl 12, which has an uncoated, inclined bottom 13. In this case, deposited on this floor 13 residues 14 of the washing or rinsing agent, the amount of these deposited residues 14, which can not be removed by the entering into the dispenser 12 water, increases with each operation of the household appliance. This problem is avoided by the coating according to Figures 1 and 2 on the wetted with a liquid surface of the household appliance in a secure manner. Since a hydrophobic and oleophobic coating of the soil is accordingly provided, the washing or rinsing agent introduced into the dispensing bowl is completely transported into the household appliance with the water flowing into it. reference numeral

dispenser tray

Side wall

ground

outlet opening

coating

water inlet

wall

substratum

border liquid

Overlay

dispenser tray

ground

arrears

Claims

claims

Component (1) of a domestic appliance, which is wetted by a liquid and is provided on its coming into contact with the liquid surface with an at least hydrophobic coating, characterized in that the at least hydrophobic coating (6) as a liquid boundary layer, the a substrate (9) and a boundary liquid (10) embedded therein, is formed, wherein the boundary liquid (10) relative to the liquid wetting the component (1) forms a sliding layer (1 1) repelling the liquid.

Component according to claim 1, characterized in that the substrate (9) has a nanoporous structure.

Component according to claim 1, characterized in that the substrate (9) is formed as a porous, mesh-like network, in which the boundary liquid (10) is embedded.

Component according to Claim 1, characterized in that the substrate (9) is produced by etching, laser structuring, corrosion, plasma processing or structured growth.

Component according to claim 1, characterized in that the liquid boundary layer acts both hydrophobic and oleophobic.

Component according to one of the preceding claims, characterized in that the wetted with a liquid component is a water tank of a steam iron, a water-absorbing component of a kettle or a heating pocket of a washing machine.

7. Component according to one of claims 1 to 5, characterized in that the wetted with a liquid component is a dispenser shell (1) of a dishwasher or washing machine.

8. Component according to one of claims 1 to 5, characterized in that the wetted with a liquid component is a door seal, a pump component, a heat exchanger component or a Dosiereinrichtungsbauteil.

9. Component according to one of the preceding claims, characterized in that the wetted with a liquid component is a cooling surface of a refrigerator or freezer cabinet.