DE102009039872A1 - Handle with surface coating and process for its preparation - Google Patents

Abstract

The invention relates to a handle, in particular for a door leaf or window leaf, with a surface coating. According to the invention, it is provided that the surface coating contains a glass-like layer. This is preferably produced by a sol-gel process.

Description

The present invention relates to a manually operable element, in particular for a door leaf or a window leaf, with a surface coating.

The wing elements of doors or windows have fittings that have to operate the wing elements manually operable elements. The manually operable elements can be, for example, door handles, door knobs, gripping elements, such as window handles, or planar control elements. These operable elements may preferably be made of a metallic material such as steel, aluminum or brass. In the following, a manually operable element is only briefly called "handle", but should not be limited to the meaning of a handle in the narrower sense, but includes all conceivable elements that can be attacked manually to open, such as a simple with metal clad surface, against which you only have to press to open without further complex steps.

Such handles are often painted for visual reasons, such as to adapt to a color of a door panel. A paint also serves to protect the handle, for example, against oxidation or corrosion of a metal handle.

Conventional coatings, such as coatings, have the disadvantage that their mechanical properties, such as abrasion resistance and scratch resistance, are too low for long-term use. Therefore, they can fulfill their task of corrosion protection only as long as it has not come to damage the paint, which are so deep that locally the layer is no longer available. In particular, objects such as rings and keys, which are brought by the handle-actuated persons against the handle, damage the coating layer heavily.

Another known surface layer on handles is an anodization. However, this electrically generated oxide layer can only be produced on aluminum and is particularly susceptible to scratching against metallic objects, such as rings or keys. In addition, the layer thickness is low and therefore again particularly susceptible to mechanical stress.

The object of the present invention is therefore to provide a handle, in particular a door or a window, with a surface coating which overcomes the disadvantages of the prior art. In particular, the handle should have a surface layer which has a high mechanical resistance and causes a very good corrosion protection. Another object is to propose a method of making such a handle.

The object is achieved with a handle according to the features of claim 1. Advantageous developments of the invention are specified in the dependent claims 2 to 7.

An inventive handle has a glassy layer as the surface layer.

In the context of the present invention, "glassy" refers to a substantially amorphous structure which to a large extent has inorganic constituents.

A vitreous layer has the advantage of being specifically transparent, having a high mechanical strength, in particular a high abrasion resistance and scratch resistance, and a high hardness. Furthermore, it hermetically seals a surface of the handle, which surprisingly results in very good hygiene properties, because cavities and depressions in which germs can settle are not or at least hardly present.

Furthermore, a vitreous layer has a high thermal stability. The connection to a metal handle is surprisingly high. Advantageously, at an interface between a metal (Me) of the handle and the vitreous layer, there are covalent bonds between Me and O of an oxide of the vitreous layer.

Preferably, the glassy layer is a glassy layer made by a sol-gel process.

The sol-gel process will be explained below.

In the glassy layer are preferably organic radicals, such as methyl groups (-CH ₃ ) before. These advantageously have the consequence that the glassy layer has a water-repellent property. This facilitates cleaning of the handle. The organic radicals can be introduced into the glassy layer, for example, by a sol-gel process.

The glassy layer preferably comprises glass formers which contain at least one element from a group consisting of Si, Al, B and P. This has the advantage that the glassy layer has a particularly good adhesion to a metal (Me) of the handle, because it has been shown that Me-O- (Si / Al / B / P) bonds are particularly stable.

In a particularly advantageous handle, a three-dimensional crosslinking in the glassy layer is suppressed. This results in a lower rigidity and thus a higher flexibility of the layer. Thus, the glassy layer can have a low brittleness despite a high hardness. This protects against breakage and flaking off of parts of the layer, which instead can flexibly avoid a load within certain limits under mechanical load and thus is less easily damaged.

Preferably, the glassy layer has a thickness between 1 and 10 microns, in particular between 2 and 5 microns. This is made possible by the sol-gel process and ensures a particularly high stability and abrasion resistance.

The object of the present invention is further achieved by a method according to the features of claim 8. Advantageous developments of the method according to the invention are specified in the dependent claims 9 to 14.

• – Bereitstellen eines Metallgriffkerns,
• – Bereitstellen eines Sols mit Prekursoren, das geeignet ist, in eine glasartige Schicht überführt zu werden,
• – Erzeugen eines Nassfilms auf dem Metallgriffkern durch Beschichten des Metallgriffkerns mit dem Sol,
• – Umwandeln des Nassfilms in eine Xerogel-Schicht durch einen Trockenschritt,
• – Umwandeln der Xerogel-Schicht in eine glasartige Schicht durch einen thermischen Verdichtungsschritt.

According to the inventive method, a handle, in particular a handle according to the invention, is produced by providing a metal grip core and producing a glassy layer on a surface of the handle with a sol-gel process. The method advantageously comprises the following steps:

• Providing a metal grip core,
• Providing a sol with precursors capable of being converted into a vitreous layer,
• Forming a wet film on the metal grip core by coating the metal grip core with the sol,
• Converting the wet film into a xerogel layer by a drying step,
• Converting the xerogel layer into a vitreous layer by a thermal densification step.

A sol is a colloidal dispersion of sol particles with sizes in the nanoscale, which arise in first basic reactions from precursors.

Prekursoren are advantageously metal alcoholates, such as tetraethoxysilane (TEOS) or methyltriethoxysilane (MTEOS). Also suitable are, for example, metal carboxylates. Such a precursor, preferably dissolved in a mixture of alcohol and water, hydrolyzes rapidly in acid or alkaline. Accordingly, the solution is preferably made acidic or alkaline. MOH groups of partially hydrolyzed precursor molecules condense with dehydration and thus grow to particles. By building up a network of sol particles, a gel is formed upon gelation. This is a viscoelastic solid, in the gel framework still solvent is included. By drying the gel, a xerogel is formed, the framework of which experiences a strong shrinkage with respect to the gel, while at the same time decreasing the porosity.

In the context of the invention, the handle is advantageously coated with a sol of suitable viscosity, the viscosity being adjusted as a function of the coating method to be used. The viscosity can be adjusted by the degree of condensation, the concentration and other parameters of the sol. Depending on the viscosity, for example, layer thicknesses in the range of several micrometers can be set up to 20 μm.

Advantageously, the sol layer is applied by a dipping method or a spraying method. These methods are simple and therefore inexpensive.

During drying, the thickness of the layer shrinks, whereby a compression of the porosity already occurs. After drying, the coated handle, whose layer is formed by a xerogel at this time of the process, is heated to temperatures at which compression sets in, preferably in the range of a glass transition temperature T _{g of} the glass formers, for example to temperatures between 450 ° C. and 1000 ° C, in particular between 500 ° C and 800 ° C, in particular between 500 ° C and 600 ° C.

In the course of compaction, the solid areas diffuse and / or flow together and the air in the pores migrates out of the layer. At the end of the densification step, a glassy layer is obtained, which only has a low porosity.

Furthermore, the sol layer and thus the glassy layer can be colored. This can advantageously be done by a pigment incorporation, for example with a spinel, iriodin and / or mullite, or by a Koiloideinbau, in particular with noble metal colloids.

The sol or xerogel layer can advantageously be converted into a glass-ceramic protective layer. This has the advantage of increased temperature resistance to, for example, about 1000 ° C, good tribological properties and good cleanability.

Advantageously, the solids content of the sol is increased, so that a lower shrinkage can be achieved until reaching the xerogel layer or the glassy layer. This reduces the pore volume even before compression. The solids content can be achieved for example by a higher number of nanoparticles in the sol.

Further advantageous embodiments and further developments of the invention are described with reference to a preferred embodiment in conjunction with two figures.

Showing:

1 : a schematic representation of a coating process of a door handle,

2 : a schematic representation of a sol-gel process.

According to a preferred embodiment, a door handle 1 with a metal handle core 8th made of steel with a glassy layer 2 Mistake. The steel in this example is a stainless steel (here 1.4301), but can be any other steel, the door handles 1 suitable is. The metal handle core 8th will, as in 1 shown schematically, by dip coating with a sol 3 Mistake. This is the metal handle core 8th into a vessel 4. with sol 3 dipped ( 1a ) and pulled out at a defined speed ( 1b and 1c ).

As sol 3 an alcohol-water mixture is used in which TEOS is dissolved. In addition to this silicon compound, alcoholates and / or carboxylates or other sol-gel type chemical compounds containing Al, B and / or P can be used.

During extraction of the metal handle core 8th from the sol 3 creates a wet film 5 as a layer on the latch 1 ( 1c ). By subsequent drying ( 1d ) solidifies the wet film 5 ,

In another embodiment, the wet film 5 applied by spraying (not shown). This allows a very thin and even wet film 5 to create.

In 2 the process is shown schematically during drying. The wet film 5 contains sol particles 6 with particle sizes in the nano range. By drying, preferably at elevated temperature, represented by "k · T", the solvent mixture of alcohol and water is removed and the sol particles 6 move closer together, reducing porosity and compacting the layer. The result is a xerogel layer 7 , This is then heated in the range of a glass transition temperature T _g , which is 500 ° C in this embodiment. The individual particles sinter together, the porosity escapes and the layer is densely compressed. Obtained is a high-density vitreous layer 2 whose main constituent is SiO ₂ . By introducing ions into the sol, the glass of the glassy layer can be modified. For example, alkalis as fluxes can reduce the necessary sintering temperature.

The glassy layer 2 has a high transparency, a high mechanical strength, abrasion resistance, scratch resistance, protects the steel of the door handle 1 Against corrosion, has a smooth surface that is easy to clean and therefore meets high standards of hygiene, has a high temperature and thermal shock resistance and adheres very well to the substrate made of stainless steel. This is due to the high number of Me-O-Si bonds that form at an interface between the steel and the glassy layer 2 have formed.

With the same coating method, sheets of the same stainless steel with the same sol under identical coating parameters as the doorknob were used for measurements 1 coated. The layer was dried and compacted with the same parameters. Measurements of hardness and abrasion resistance were made on the obtained layers. As universal hardness, a mean value of about 3000 MPa was measured, which is higher than that of the stainless steel itself. In another embodiment, 4% of potassium was used in the sol based on the content of TEOS. It then gave hardness of more than 3700 MPa.

Furthermore, a very good anti-adhesion effect was measured on the samples. Also, the samples were easy to clean.

In another example, aluminum plates were coated as described in the first embodiment for steel. A roughness depth R _t of 9.8 μm was measured for the uncoated aluminum surface. After coating and densification, a roughness R _t of 3.7 μm was measured for the aluminum plate provided with the glassy layer. It is believed that the lower roughness is a major reason that the surface has a better anti-adhesion effect and is easier to clean.

Furthermore, organic residues in the layer could be detected, such as -CH ₃ groups. These residues are also the reason why the layer is easy to clean.

In another embodiment, pigments are added to the sol which are incorporated into the network in the later glassy layer and color the glassy layer. These are spinel, iriodin and mullite in the embodiments.

In still other embodiments, the glassy layer is colored by using noble metal colloids.

In a further embodiment, a sol having a composition is used which allows the vitreous layer to form a glass ceramic during the compaction step and / or the subsequent temperature treatment.

This is black in this case. This may be desirable for a variety of applications for visual reasons. This glassy layer has very good tribological properties and has a temperature resistance up to about 1000 ° C.

Also, all the samples, ie both steel and aluminum plates, showed in the coated state after a salt spray test DIN 50021 a significantly lower corrosion, which proves the very good corrosion protection by a glassy layer.

The invention is not limited to the exemplary embodiments mentioned in the exemplary embodiments. In particular, glassy layers can be applied to handles with any metals and the composition of the glassy layer can be adjusted in coordination with the metal to be coated and the desired properties of the glassy layer. For this purpose, in particular the precursors and fillers used can be varied accordingly.

All features mentioned in the description, examples and claims may contribute to the invention in any combination.

LIST OF REFERENCE NUMBERS

1

Handle, doorknob

2

Glassy layer

3

Sol

4

vessel

5

wet film

6

sol particles

7

Xerogel layer

8th

Metal handle core

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN 50021 [0047]

Claims (14)

Handle ( 1 ), in particular for a door leaf or window leaf, having a surface coating, characterized in that the surface coating comprises a vitreous layer ( 2 ) having. Handle ( 1 ) according to claim 1, characterized in that the vitreous layer ( 2 ) is produced via a sol-gel process. Handle ( 1 ) according to claim 1 or 2, characterized in that the glassy layer comprises at least one glass former containing at least one element selected from the group consisting of Si, Al, B and P. Handle ( 1 ) according to one or more of the preceding claims, characterized in that the vitreous layer ( 2 ) contains a glass ceramic. Handle ( 1 ) according to one or more of the preceding claims, characterized in that the vitreous layer ( 2 ) contains organic radicals. Handle ( 1 ) according to one or more of the preceding claims, characterized in that present in the glassy layer pigments such as spinel, iriodin and mullite, and / or noble metal colloids. Handle ( 1 ) according to one or more of the preceding claims, characterized in that the glassy layer has a thickness between 1 and 10 microns, in particular between 2 and 5 microns. Method for producing a handle ( 1 ), in particular for a door leaf or window leaf, in particular a handle ( 1 ) according to one or more of claims 1 to 7, characterized by the steps - providing a metal handle core ( 8th ), - providing a sol ( 3 ) with precursors suitable for placing in a vitreous layer ( 2 ), - producing a wet film ( 5 ) on the metal handle core ( 8th ) by coating the metal handle core ( 8th ) with the sol ( 3 ), - converting the wet film ( 5 ) into a xerogel layer ( 5 ) by a drying step, - converting the xerogel layer ( 5 ) in a glassy layer ( 2 ) by a thermal densification step. A method according to claim 8, characterized in that is used as a precursor TEOS and / or MTEOS. Method according to claim 8 or 9, characterized in that the wet film ( 5 ) is produced by dip coating or spray coating. Method according to one or more of claims 8 to 10, characterized in that the thermal densification step in the range of a glass transition temperature of a glass former in the xerogel layer ( 5 ) is carried out. Method according to one or more of claims 8 to 11, characterized in that the thermal densification step between 450 and 1000 ° C, in particular between 500 and 800 ° C, in particular between 500 and 600 ° C is performed. Method according to one or more of claims 8 to 12, characterized in that a sol ( 3 ), the solids content of which is increased by the addition of nanoparticles. Method according to one or more of claims 8 to 13, characterized in that the xerogel layer ( 5 ) is converted into a glass ceramic layer.

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