EP2533909A2

EP2533909A2 - Metal component, method for producing a metal component, and fitting, furniture, and/or large household appliance

Info

Publication number: EP2533909A2
Application number: EP11705176A
Authority: EP
Inventors: Daniel Rehage; Lars Schrubke; Klaus-Dieter Kampmeier
Original assignee: Paul Hettich GmbH and Co KG; BAF Industrie und Oberflaechentechnik GmbH
Current assignee: Paul Hettich GmbH and Co KG; BAF Industrie und Oberflaechentechnik GmbH
Priority date: 2010-02-09
Filing date: 2011-02-03
Publication date: 2012-12-19
Also published as: WO2011098390A2; US20130017401A1; DE102010000344A1; WO2011098390A3; EP2612711A1

Abstract

The invention relates to a fitting, item of furniture, and/or large household appliance constructed of metal components, wherein the metal component comprises a coating at least in sections, comprising at least one perfluoralkoxy-copolymer (PFA), to a method for the production thereof, and to a fitting, an item of furniture, and/or a large household appliance.

Description

The present invention relates to a metallic component, in particular for a fitting, a furniture and / or a large household appliance and a method for its production and a fitting, a furniture and a metal component / or large household appliance.

Metallic components, in particular fittings in household appliances are subjected to extreme conditions, in particular grease and dirt deposits, which significantly affect the life and functioning of such components.

There are known fittings which are provided to improve their cleanability with a PTFE coating. However, PTFE is difficult to process and requires a great deal of labor and energy during the coating process. PTFE coatings also tend to flake off at higher surface tensions and under mechanical stress.

It is therefore an object of the present invention to provide a metallic component which is inexpensive to produce and also easy to clean, and a method for its production.

The invention solves this problem by the features of claim 1, 15, 21, 22 and 23.

In this case, a metallic component, in particular a fitting, a furniture and / or a household appliance according to the invention at least partially a coating which comprises at least one perfluoroalkoxy copolymer (PFA), formed from tetrafluoroethylene and a perfluoro (alkyl vinyl ether).

In this case, the copolymer may be formed as a random copolymer, gradient copolymer, block or graft copolymer, but preferably as an alternating copolymer. The coating has an excellent sliding property, a high alternating temperature resistance and, in addition to PTFE, improved non-stick properties. lower flaking tendencies and improved scratch resistance.

In an advantageous embodiment, the coating contains at least 80% of a polymer blend of the copolymer and a polyether ketone. On the one hand, polyether ketones are resistant to high temperatures, so that the operating temperature of the coated fitting is increased from about 300.degree. C. to about 350.degree. Polyether ketones also have excellent impact resistance and increase the hardness of the coating.

This is the case in particular when polyetheretherketone (PEEK) is advantageously used as the polyetherketone.

It has surprisingly been found that even a mass fraction of 10-40% of a polyether ketone leads to a multiplication of the scratch resistance of the PFA

Coating leads and a firmer adhesion of the coating on the metallic surface of the component.

It is advantageous if the fitting has a dynamic coefficient of friction between 0.15-0.4 by appropriate treatment of the coating. Thus, the coating can be advantageously applied for example on running surfaces of pullout guides, which improves the running quality of the pullout guides and at the same time allows the use of such pullout guides in ovens due to the high temperature resistant PFA coating.

It is furthermore advantageous if the surface of the coating has a ball-pressure hardness according to DIN 53456 between 30-95 N / mm ² . Fittings, furniture and / or household appliances are sometimes exposed to high mechanical loads. By appropriate formulation of a polymer blend or other treatment of the PFA copolymer of the coating, the ball pressure hardness can be optimized so that the metallic component has a high resistance to mechanical loads and abrasive forces.

It is advantageous if the coating is arranged in multiple layers. This is the case in particular if different areas of the metallic component, in particular of the fitting, are subjected to different forces and conditions. So are the outer surfaces of a drawer slide in one Oven, for example, a high degree of contamination of fat splashes and food residues, so that a high cleanability but also a corrosion protection must be made for these surfaces. The running surfaces of the pullout guide are subject to rather high mechanical loads. Depending on the surface, the coating according to the invention can be optimized by a multilayer structure in such a way that the advantageous properties of the copolymer are supplemented by further layers of polymer blends which, however, mainly contain PFA. In the case of drawer guides, for example, it is particularly advantageous if the coating has at least two layers, wherein the uppermost layer advantageously has a dynamic coefficient of friction of less than 0.3 and thus a high degree of lubricity. The layer arranged underneath has a ball-pressure hardness of at least 0.35 N / mm ² , preferably at least 0.8 N / mm ² , so that it represents increased scratch and corrosion protection on account of its hardness.

For a particularly effective corrosion protection, it is advantageous if the uppermost layer has a maximum of 20% of the layer thickness of the underlying layer.

It is for example to improve the running quality of drawer guides advantageous if lubricant is incorporated into the coating, in particular in the region of the running surfaces of drawer guides, so that the lubricant is determined by the coating on the surface of the fitting.

For improved optics, it is also advantageous if the coating is transparent or translucent. Alternatively or additionally, the coating at least partially color pigments, for example in the form of graphite, mica, titanium dioxide or the like, which color the coating, for example in the colors white, light gray or anthracite. Dark colors are preferred in ovens, cooking appliances and accessories used for them. In particular, for cooling equipment, the coating can also be colored white, for example by the use of titanium dioxide. Transparent coatings are used in fittings, furniture and household appliances Use. Coatings for furniture are dyed according to the customer's request and the chemical technical possibilities.

To prevent tarnish, improve the corrosion protection and to achieve a specific surface structure, it is advantageous if the metallic component has a metallic coating on which the coating is applied.

According to the invention, a method for producing a metallic component comprises the following steps:

Forming and / or forming the metallic component,

Pretreatment of the component,

Applying the coating comprising at least one copolymer formed from

Tetrafluoroethylene and a perfluoro (alkyl vinyi ether)

optionally curing and sintering the applied coating, and cooling the coated component.

This method can be integrated into the mass production of fittings, furniture and household appliances accordingly.

It is advantageous if by pretreatment of the metallic component, a degreasing and / or cleaning and / or washing and / or pickling of the surface of the component takes place, so that an improved adhesion of the coating is ensured on the surface. This can preferably be effected by wet-chemical cleaning processes, but can also be achieved, for example, by thermal treatment of the components.

It is advantageous if, after the forming and / or reshaping of the metallic component and / or after the pretreatment of the component, a smoothing of the surface takes place, so that even with small layer thicknesses the corresponding

Surface is fully coated with the coating and no bumps protrude from the surface and a uniform surface is formed for adhering to the coating. The smoothing of the surface can be done by grinding, polishing, blasting or other common methods.

To prevent tarnish it is advantageous if the curing and sintering of the coated component takes place under an oxygen-poor atmosphere. To improve the cleanability, it is advantageous if, after the coating of the component, a laser processing of the coated surfaces takes place. The hydrophobicity of the coating is increased and an increase in the contact angle of a drop of liquid on the coating surface of up to 10 ° is achieved. It has surprisingly been found that the laser processing can be particularly effective at a wavelength between 60 to 210 nm. It is also advantageous if the application of the coating by plastic flame spraying, since thus a higher coating density, strength binding forces to the metallic surface and between the polymer molecules, and a high coating efficiency can be achieved. According to the invention, at least one metallic component according to the invention is arranged on or in a fitting, a piece of furniture, a household appliance, in particular a refrigerator, dishwasher or oven. In particular, in the field of large household appliances prevail in some extreme conditions. Thus, a coating used in an oven must have a temperature resistance of 250 ° C. to 300 ° C. and be easy to clean from fat splashes and the like. Coatings in refrigerators and freezers must not become brittle or fragile at temperatures below zero and must be resistant to condensation and ice. Dishwasher coatings must be alkali resistant and moisture resistant at temperatures up to 100 ° C. All these conditions are met by the metallic component according to the invention, in particular a fitting, so that it can be used universally in all areas of household large appliances. Therefore, fittings for certain applications need not be produced separately, which brings a considerable advantage in terms of labor, equipment and material costs.

Furniture in the sense of this application are furniture components such as e.g. Drawers but also household appliances such. Ovens, dishwashers, refrigerators and freezers, washing machines and dryers.

The invention will be explained below with reference to several embodiments with reference to the accompanying drawings. Show it: several views of a first embodiment of a metallic component according to the invention as a pull-out guide, two views of a further embodiment of a metallic component according to the invention as a pull-out guide with splash guard,

two views of a third embodiment of a metallic component according to the invention as oven hinge, and two views of a fourth embodiment of a metallic component according to the invention as a refrigerator hinge.

Fig. 1-3 show a telescopic drawer guide in the form of a full extension. A pullout guide 1 comprises a guide rail 2 which can be fixed to a side rail in an oven, a side wall of a baking oven or a furniture body. On the guide rail 2, a center rail 3 is movably mounted on rolling elements 6. The middle rail 3 serves to support a running rail 4. For mounting the rails 2, 3 and 4, three raceways 8 for rolling elements 6 are respectively formed on the guide rail 2 and the running rail 4. The rolling elements 6 are held on a Wälzkörperkäfig 7 as a unit. Further, a total of six raceways 8 are formed on the center rail 3 for rolling elements 6, wherein in each case three raceways 8 of the guide rail 2 and three tracks 8 of the running rail 4 are assigned. Furthermore, telescopic drawer guides can also be designed as a partial drawer without middle rail or as a full or over extension with one or more middle rails.

For fixing the pullout guide 1 on a side rail of a baking oven two brackets 5 are fixed to the guide rail 2. Other fastening means may be provided on the guide rail 2. The pullout guide 1 is made of metal, preferably stainless steel. The pullout guide 1 is at least at the externally accessible areas, ie on the outside of the guide rail 2 and the running rail 4 with a

Perfluoroalkoxy copolymer (PFA) coating provided. The coating mainly contains a copolymer formed from

Tetrafluoroethylene and a perfluoro (alkyl vinyl ether), for example poly (perfluorovinyl methyl ether). This copolymer is known inter alia as Perfluoralkoxylalkan (PFA) and has over PTFE over advantageous properties in terms of its processing and also with regard to the adhesion of the polymer chains with each other.

The copolymer is accessible, for example, by spraying, in particular flame spraying, and can therefore be applied to a metallic surface both in a solvent-based dispersion and as a solvent-free polymer.

A stopper 10 fixed to the running rail 4 is likewise coated with the PFA-containing coating at its externally accessible areas. Also, a retaining pin 11 is equipped with a PFA-containing coating. The inside of the running rail 4 and the guide rail 2, on which the tracks 9 are formed for the rolling elements 6, has no coating. The middle rail 3, which is arranged completely in the inner region of the pullout guide 1 when the running rail 4 is arranged in the retracted position, has no coating at least in the region of the raceways 8. In this case, the raceways 8 may be formed by the material of the rails 2, 3 and 4. Most of the raceways 8 and 9 are made of a bent sheet steel. On the outside, the PFA-containing coating on the rails 2 and 4 enables easy cleanability. Since the range of application of the perfluoroalkoxy copolymer extends up to 300 ° C, the pullout guide 1 can be used particularly well in an oven, wherein in addition a long service life and a high running quality of the pullout guide is achieved.

To be used in the home, especially in the kitchen, the coated drawer slides must comply with FDA guidelines for contact with food. Since the coating material was classified according to various safety data sheets harmless to health, is a

Application for contact with food, for example in ovens and on food supports possible.

In a further embodiment, the inside of the running rail 4 and the guide rail 2, on which the raceways 9 are formed for the rolling elements 6, provided with a lubricant-containing PFA coating. The middle rail 3, which is completely arranged in the interior of the pullout guide 1 is net, when the running rail 4 is arranged in the retracted position, has at least in the region of the raceways 8, this lubricant-containing coating. The coating in the region of the running surfaces can consist, for example, of 90% PFA, 5% adhesion promoter and 5% molybdenum sulfide, based on a mass file.

Fig. 4 shows a cap 12, which can be fixed to the pullout guide 1. This cap is made of a metal sheet, preferably a steel sheet and is provided at least on the outside with the perfluoroalkoxy copolymer coating, which prevents fat deposits on the one hand on the metal surface, on the other hand causes a moisture protection at temperatures of 250 to 300 ° C. The locking means 13 also have the coating. Fig. 5 shows the definition of the pullout guide 1 with the cap 12 on the side rail 14 of a baking oven. For an advantageous cleanability, it is also recommended to provide the side rails 14 of a baking oven with the coating. Fig. 6-8 show an oven 20 with a hinge 21. The hinge 21 is composed of a housing 22 in which a linear lever 23 is arranged this linear lever 23 is connected by a rivet 33 with a transfer lift! 24 coupled. On the longitudinal axis of the linear lever 23 extends a compensating spring 30, which is wiggled around the shaft of the linear lever 23 and can be braced by movement of the linear lever 23. The transmission lever 24 is pivotally coupled to a door lever 25 via a rivet connection 32 which is coupled to an oven door. At the level of the transmission lever 24, a closing lever 29 is also arranged in the housing 22, which is defined by a rivet 26 and which has a latching nose which engages in a latching rivet 27 in a guide in the

Transmission lever 24 is movably mounted. The rivet 26 also has a pressure roller 31 for partially receiving a force by the

Door lever is exerted on the rivet connection 26. The shank of the closing lever 29 is provided with a closing spring 28, which is tensioned and relaxed by movement of the hinge 21. In the present embodiment, all components may be provided with a corresponding PFA-containing coating, but in particular the area areas, such as the housing 21 and the door lever 25. Fig. 8 shows a refrigerator 41 with hinges 42 which on the refrigerator door 43 and the Refrigerator body 44 are attached and allow the opening of the refrigerator 41. Here, Fig. 10 shows a possible embodiment of such a hinge 42, each with two base plates 45, 46 and a hinge arm 47 again. The surface of the hinge must be completely provided with the PFA-containing coating, in which case polymer blends with polyether ketones, in particular PEEK, are particularly preferably used. The coating provides protection against dirt and impurities, which accumulate on the metal surface and allow excellent cleanability of the fittings. Furthermore, the coating provides corrosion protection for iron components, which are not attacked by the harsh environmental conditions in refrigerators and freezers. In this case, PFA adheres to the metallic surface even at temperatures of -50 to 0 ° C, without splitting due to embrittlement or temperature-dependent material expansion.

The metallic component according to the invention, in particular as a fitting basically comprises all fitting variants, such as hinges, suspensions, furniture and decor fittings for the exterior and interior, but in particular drawer guides. Due to the high alternating temperature resistance, the coated fittings can be used universally in ovens at around 300 ° C as well as in refrigerators at -50 ° C. Furthermore, the coated fittings can also be used in furniture under extreme climatic conditions, such as sea climate with salty air high humidity. The coating offers metallic steel components excellent corrosion protection and is also more scratch-resistant than the previously known PTFE coatings. The coating can be applied in thicker layers than PTFE. In addition, the coating is more resistant to high surface stresses compared to a PTFE coating. This is due, inter alia, to the fact that the copolymer used is a thermoplastic in which the individual polymer compounds are fused and not merely glued with adhesion promoters, as in PTFE the case is. The coating has a critical surface energy of 17.0 mN / m and thus a better cleanability than PTFE (18 mN / m), wherein the cleanability of the coating according to the invention can be improved even better.

The production of a metallic component according to the invention, in particular a fitting, a piece of furniture and / or a household appliance, for example, according to the following method: First, a metallic component of a metal workpiece by bending, pressing, punching, casting and the like is brought into a predetermined shape.

Subsequently, the component is deburred and degreased and cleaned by wet-chemical pretreatment. The cleaning temperature is for example 50 to 100 ° C, preferably 60 to 80 ° C. After 3 to 10 minutes, preferably 4 to 6 minutes of cleaning treatment, the components are first flushed with normal water or city water (15 to 25 ° C) and then with demineralized water (15 to 25 ° C). The drying of the metallic components takes about 5-10 min at about 50 to 150 ° C. This can preferably take place at a continuously rising temperature from 80 to 150 ° C. in recirculation mode.

After completion of the pretreatment steps, a mixture of the copolymer, formed from tetrafluoroethylene and a perfluoro (alkyl vinyl ether), and a primer as a solvent-based dispersion is applied to the metallic surface. The primers serve as additional adhesion promoter between the coating and the metallic surface of the component. Both organic solvents and water are detected as solvents. The coating can also be applied in multiple layers, wherein each layer may have a different concentration of primers or different PFA-containing polymer biends. In addition, a cover layer can be applied in powder form to the layers applied as a dispersion and dried. A monolayer system can be produced by directly applying the cover layer or a combined layer of primer and top coat on the surface of the metallic component. A two-layer system may consist of a Haftvermittier and a cover layer. A multilayer system may comprise at least one layer of adhesion promoter and a cover layer and at least one intermediate layer consist. Adhesion promoter, topcoat and intermediate layer may contain, in addition to the mixture of the copolymer formed from tetrafluoroethylene and a perfluoro (alkyl vinyl ether), solvents, ceramic additives as fillers or to increase the layer hardness, color pigments, PEEK or PTFE.

A liquid adhesion promoter can also be combined with powdery intermediate and / or outer layers.

The layers are applied in a spraying process by means of HVLP spray guns (HVLP - High Volume Low Pressure), the metallic components preferably being suspended. The HVLP painting process is a low-pressure process that reduces the volatile organic compounds and thus reduces the environmental impact. Alternatively or additionally, the coating can also be effected by electrostatic systems, for example by powder or wet paint application.

The drying of the Beschi.ch.tung coating takes place at 50 to 180 ° C, preferably 80 to 150 ° C over a period of 5 to 15 min. The subsequent sintering process is carried out at a temperature of 390 to 450 ° C, preferably from 400 to 420 ° C at a time of 5 to 20 minutes, preferably 8 to 15 min.

The cooling is preferably carried out in different temperature ramps in order to achieve the most uniform possible formation and flow of the layer during cooling on the surface and to prevent stress cracks in the coating.

The applied dry film thickness is after sintering 5 to 50 μιη, preferably 15 to 35 μιη.

An alternative application method consists of PFA coating by plastic fiber scribing. By plastic flame spraying an advantageous application of PFA layers is possible. The powdery PFA copolymer or copolymer blend is melted over a suitable injection device in an acetylene-oxygen flame beyond 3000 ° C and sprayed onto the component to be coated Due to the high temperatures, the copolymer melts completely in the flame and spreads more uniformly on the surface than other application methods.

This results in a particularly high aterialdichte and improved binding forces of the individual polymer molecules with each other and to the metallic substrate. In addition, higher layer thicknesses of, for example, 00 to 700 pm can be achieved. The additional process step of sintering can advantageously be dispensed with in this coating process.

In a post-treatment step, the hydrophobicity or the non-stick effect of the coating can be additionally increased by laser irradiation. In this case, for example, an exciter laser (ArF) with a wavelength of 193 nm can be used. In the case of irradiation, superficial removal of unevenness occurs, whereby the non-stick properties are improved and superhydrophobic properties of the surfaces of the metallic component arise, so that once again an improvement in the cleanability can be achieved.

LIST OF REFERENCES

1 pullout guide r Pull-out guide

1 "pullout guide

2 guide rail

2 'guide rail

2 "guide rail

3 middle rail

3 'middle rail

4 track rail

4 'track

4 "track

5 clip

6 rolling elements

6 'rolling elements

7 rolling element cage

T rolling element cage

8 career

8 'career

9 career

9 "career

10 plugs

11 retaining bolts

12 cap

13 locking means

14 side rails

20 oven

21 hinge

22 housing

23 linear lever

24 Transfer fee

25 door lever

26 rivet connection

27 snap rivet

28 closing spring

29 closing lever

30 balancing spring

31 pressure roller

32 rivet connection

33 Rivet connection

34 Rivet connection Refrigerator hinge

Refrigerator door refrigerator carcass

Claims

claims

1. Metallic component, in particular for a fitting (1, 12, 14, 21, 42) a furniture and / or a household appliance, characterized in that the metallic component has at least in sections a coating comprising at least one perfluoroalkoxy copolymer (PFA).

2. Metallic component according to claim 1, characterized in that the coating contains at least 80% of a polymer blend of the copolymer and PTFE.

3. Metallic component according to claim 1 or 2, characterized in that the coating contains at least 80% of a polymer blend of the copolymer and a polyether ketone.

4. Metallic component according to claim 3, characterized in that the polyether ketone is polyetheretherketone (PEEK).

5. Metallic component according to one of the preceding claims, characterized in that the polymer blend has a mass fraction of 10 to 40%.

PTFE or a polyether ketone and contains 60 to 90% of the copolymer.

6. Metallic component according to one of the preceding claims, characterized in that the surface of the coating has a dynamic coefficient of friction between 0.15-0.4.

7. Metallic component according to one of the preceding claims, characterized in that the surface of the coating has a ball pressure hardness according to DIN 53456 between 30-95 N / mm ² .

8. Metallic component according to one of the preceding claims, characterized in that the coating is arranged in one or more layers.

9. Metallic component according to one of the preceding claims, character- ized in that the coating has at least two layers, wherein a first layer is arranged on the surface of the metallic component and has a ball pressure of at least 0.35 N / mm ² and a second layer is disposed above and has a dynamic coefficient of friction of less than 0.3.

10. Metallic component according to claim 9, characterized in that the second layer has a maximum of 20% of the layer thickness of the underlying first layer.

11. Metallic component according to one of the preceding claims, characterized in that the coating contains lubricant.

12. Metallic component according to one of the preceding claims, characterized in that the coating is transparent or translucent.

13. Metallic component according to one of the preceding claims, characterized in that the coating contains color pigments.

14. Metallic component according to one of the preceding claims, characterized in that the metallic component has a metallic coating.

15. A method for producing a metallic component, in particular for a fitting, a furniture and / or household appliance, the method comprising the following steps:

a) forming and / or forming the metallic component,

b) pretreatment of the component,

c) applying the coating comprising at least perfluoroalkoxy copolymer

(PFA)

d) If necessary Curing and sintering the applied coating, and e) cooling the coated component.

16. The method according to claim 15, characterized in that by pretreatment of the metallic component degreasing and / or cleaning and / or washing and / or pickling of the surface of the component takes place.

17. The method according to claim 15 or 16, characterized in that after the molding and / or forming of the metallic component and / or after the pretreatment of the component, a smoothing of the surface takes place.

18. The method according to any one of the preceding claims, characterized in that the curing and sintering of the component takes place under an oxygen-poor atmosphere.

19. The method according to any one of the preceding claims, characterized in that after cooling of the coated component, a laser processing of the coated surfaces takes place

20. The method according to any one of the preceding claims, characterized in that the application of the coating takes place by plastic flame spraying.

21, household large appliance, in particular refrigerator, dishwasher or oven, characterized in that arranged in or on the household large appliance at least one metallic component according to one of the preceding claims.

22 furniture, characterized in that arranged in or on the furniture at least one metallic component according to one of the preceding claims.

23. Fitting, characterized in that arranged in or on the fitting at least one metallic component according to one of the preceding claims.