Sprayable non-stick coating agent

Abstract

In order to provide a sprayable agent for improving the non-stick properties of surfaces and which is food-safe, the invention discloses a non-stick coating agent which comprises the following ingredients: up to 15 wt.% silicone oil, 15 to 35 wt.% methyltriethoxysilane, 10 to 30 wt.% C2-C6 alkanol, ≤ 1 wt.% C1-C4 alkanoic acid and the remainder water, wherein said non-stick coating agent has a dynamic viscosity of < 3500 mPas.

Description

[0001] Sprayable non-stick coating agent

[0002] The present invention relates to a non-stick coating agent and its use for improving the non-stick properties of a surface of a cooking, baking or roasting utensil or a small electrical appliance.

[0003] Currently, PTFE-based non-stick coatings are predominantly used in the market for pans, pots, baking pans, and small electrical appliances that require non-stick surfaces, as well as for industrial applications. However, the European Union plans to restrict the use of per- and polyfluoroalkyl substances (PFAS) in the future. A PFAS-free alternative is sol-gel coatings, often colloquially referred to as ceramic coatings, such as the GREBLON-CK product series from Weilburger Coatings GmbH.

[0004] A disadvantage of this technology is the limited longevity of the non-stick properties. While the non-stick properties of a ceramic coating deteriorate over time, other properties, such as corrosion resistance and abrasion resistance, remain fully intact even after long periods of use. However, due to the lower long-term non-stick properties compared to PTFE-based coatings, the product often no longer meets expectations after extended use and must therefore be disposed of.

[0005] There is therefore a need for a means of restoring the non-stick properties of ceramic coatings.

[0006] According to the invention, a non-stick coating agent for improving the non-stick properties of surfaces is therefore proposed, which is characterized in that the non-stick coating agent contains the following components

[0007] 5 to 15 wt.% silicone oil,

[0008] 15 to 35 wt.% methyltriethoxysilane,

[0009] 10 to 30 wt.% C2-C6 alkanol,

[0010] < 1 wt.% C1 -C4 alkane acid and

[0011] Rest water, whereby the non-stick coating agent has a dynamic viscosity of < 3500 mPas.

[0012] The non-stick coating agent according to the invention is sprayable due to its special composition and viscosity and can therefore be easily applied to the surface to be treated. For this purpose, the non-stick coating agent can be supplied in commercially available containers with a spray nozzle. The non-stick coating agent according to the invention can be purchased commercially in this form by the end user and used in the home, for example, to improve the non-stick properties of the surfaces of used cookware, bakeware, or roasting utensils, or of small electrical appliances that have been in use for a long time.

[0013] Coating with the non-stick coating agent according to the invention leads to a significant improvement in non-stick properties and is food-safe even when dried at room temperature. The drying process can be accelerated and optimized by baking at a temperature of 150°C or more for approximately 30 minutes, for example, by drying the sprayed object in an oven or on a stovetop.

[0014] Sol-gel coatings are particularly suitable as substrates, but conventional PTFE coatings are also suitable. Even use on stainless steel, cast iron, or enamel surfaces improves the non-stick properties.

[0015] The reaction which leads to the formation of the non-stick coating can be briefly described as follows, without, however, limiting the invention to the specific reaction process.

[0016] Methyltriethoxysilane is a trifunctional alkyltrialkoxysilane with three ethoxy groups. The acid contained in the non-stick coating agent according to the invention hydrolytically generates silanol groups, which form highly stable siloxane bonds (-Si-O-Si-) during the subsequent condensation reaction. The condensation reaction proceeds in parallel with the hydrolysis.

[0017] The term silicone oil refers here to unbranched diorganopolysiloxanes, whose chain structure is characterized by the general molecular formula [R1 R2SiO] n can be expressed. Silicone oils are clear liquids at room temperature (20°C) with a molecular mass of up to 150,000 g / mol.

[0018] Preferably, the silicone oil component contained in the non-stick coating agent according to the invention has a dynamic viscosity of > 100 mPas. In some embodiments, the silicone oil component of the non-stick coating agent according to the invention consists of 40 to 60 wt.% hydroxy-functional silicone oil, preferably 50 to 60 wt.%. The term hydroxy-functional silicone oil refers to silicone oils whose chain structure is characterized by the general molecular formula OH[R1 R2SiO] n H. Accordingly, hydroxy-functional silicone oils have terminal OH groups at both ends of the chain.

[0019] The C2-C6 alkanol contained in the non-stick coating composition according to the invention can be selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, and mixtures thereof. Depending on the specific application, ethanol, n-propanol, and isopropanol, as well as mixtures thereof, are preferred in certain embodiments. Some non-stick coating compositions are characterized in that the C2-C6 alkanol component consists of 60 to 100 wt. % propanol, preferably isopropanol.

[0020] The C2-C4 alkanoic acid contained in the non-stick coating composition according to the invention can be selected from formic acid, acetic acid, propionic acid, butyric acid, and mixtures thereof. Depending on the specific application, acetic acid and propionic acid, as well as mixtures thereof, are preferred in certain embodiments. Some non-stick coating compositions are characterized in that the C1-C4 alkanoic acid component consists of 60 to 100 wt.% acetic acid.

[0021] The proportions of the chemical components of the non-stick coating composition according to the invention are made up to 100 parts, with water as the remainder. In certain embodiments, deionized or distilled water is used for this purpose.

[0022] Preferably, the non-stick coating composition according to the invention consists exclusively of the components silicone oil, methyltriethoxysilane, C2-C6 alkanol, alkanoic acid, and water. In certain embodiments, the non-stick coating composition according to the invention consists of at least 95% by weight, at least 96% by weight, at least 97% by weight, at least 98% by weight, or at least 99% by weight of the aforementioned components, with the remaining portion being selected, for example, from diluents, wetting agents, propellants, dyes, pigments, and fragrances.

[0023] The non-stick coating agent according to the invention is sprayable due to its chemical composition and viscosity. The term "sprayable" is to be understood as meaning that the liquid mixture of the non-stick coating agent according to the invention can be atomized into fine droplets that form an aerosol in the ambient air. Atomization can be achieved, for example, with a single-component pressure nozzle, a pneumatic atomizer, or a rotary atomizer. In addition to atomization systems established in industrial production, conventional aerosol spray cans and pump atomizers can be used to generate aerosols, particularly for domestic use when reconditioning previously used cooking, baking, and frying appliances.

[0024] The atomization quality of a spray can be characterized by the Weber number We, which describes the ratio of inertial force to the stabilizing surface force. Particularly fine droplets can be achieved with liquids whose Weber number is > 8. Therefore, the Weber number in the present invention is preferably > 8.

[0025] One factor influencing the sprayability of the non-stick coating composition according to the invention is viscosity. In the context of the present invention, dynamic viscosity is determined using a rotational viscometer in accordance with the EN ISO 3219 standard and is expressed in mPas (millipascal second). The measurement is carried out at room temperature (23±0.2°C) with four different velocity gradients selected from the values ​​specified in the standard.

[0026] The non-stick coating agent according to the invention exhibits a high storage stability of at least 12 months and up to 24 months. Storage stability means, in particular, that the viscosity and atomization quality required for the sprayability of the non-stick coating agent according to the invention are within the above-mentioned ranges during the respective storage period. The high storage stability of the non-stick coating agent according to the invention is achieved by its special composition and, in particular, by the fact that the composition is free of silica sol (polysilicic acid).

[0027] The non-stick coating agent according to the invention is food-safe, meaning that food that comes into contact with the coating during the intended use of the coated product is still safe for consumption. Preferably, the coating produced with the non-stick coating agent according to the invention meets the food contact requirements of Regulation EC 1935 / 2004. Particularly preferably, the coating complies with the requirements of Section 31 of the German Food and Feed Code (LFGB) for the production of coatings for frying, cooking, and baking appliances.

[0028] The advantages of the present invention are achieved with a non-stick coating agent that contains the above-mentioned components in the proportions specified above. In some embodiments, the proportions of the respective components can be within the specified proportion ranges, depending on the specific application of the non-stick coating agent, but also in somewhat more specific proportions. In specific embodiments, the proportion of silicone oil is, for example, greater than 8 wt.% or even greater than 10 wt.%. In some embodiments, the proportion of silicone oil is less than 12 wt.%.

[0029] In specific embodiments, the proportion of methyltriethoxysilane is greater than 18 wt.% or even greater than 20 wt.%. In some embodiments, the proportion of methyltriethoxysilane is less than 30 wt.%.

[0030] In specific embodiments, the proportion of the C2-C6 alkanol is greater than 15 wt.% or even greater than 20 wt.%. In some embodiments, the proportion of the C2-C6 alkanol is less than 25 wt.%.

[0031] In specific embodiments, the proportion of C1-C4 alkanoic acid is greater than 0.1 wt.% or even greater than 0.2 wt.%. In some embodiments, the proportion of C1-C4 alkanoic acid is less than 0.5 wt.%.

[0032] Preferably, the non-stick coating agent is in the form of a ready-mixed product and can be applied as a 1-component system directly to the object to be coated, without the need for the addition or prior, simultaneous or subsequent application of another substance to form the coating, as is the case with 2- or multi-component systems.

[0033] The non-stick coating agent is particularly preferably in the form of a non-stick coating spray, which is preferably contained in a container with a spray device. In certain embodiments, the spray device is selected from a single-component pressure nozzle, a pneumatic atomizer, or a rotary atomizer. The spray device and container can be part of a handheld device for the consumer, such as conventional aerosol spray cans and pump atomizers. However, they can also be part of an industrial production plant. Alternatively, the non-stick coating agent can also be applied industrially using conventional spraying, dipping, or rolling processes.

[0034] The non-stick coating agent is preferably used to improve the non-stick properties of a surface of food preparation equipment, such as the surface of a cooking, baking, or roasting utensil. However, the non-stick coating agent can also be used to improve the non-stick properties of a surface of a small electrical appliance.

[0035] Appliances for preparing food include pots, pans, roasting pans, baking pans, baking sheets, and the like. Small electrical appliances include rice cookers, waffle irons, sandwich makers, milk frothers, coffee machines, electric grills, egg cookers, deep fryers, and the like—i.e., electrically operated appliances that also have surfaces that come into contact with food. Small electrical appliances also include appliances used for other applications, such as hair straighteners, irons, razors, and the like.

[0036] The non-stick coating agent is preferably used to improve the non-stick properties of a surface of previously used equipment of the aforementioned type, which has, for example, already been used as intended at least 50 times, at least 100 times, or even at least 1000 times. Alternatively, the non-stick coating agent can also be used to improve the non-stick properties of a surface of previously unused equipment of the aforementioned type.

[0037] The present invention also encompasses a method for improving the non-stick properties of a surface of a food preparation utensil or a small electrical appliance, wherein the non-stick coating agent according to the invention is applied to the surface to be treated and then dried.

[0038] The treated surface can be an unused or used conventional non-stick coating or a surface made of stainless steel, cast iron or enamel that has not previously been treated with a non-stick coating.

[0039] In some embodiments of the process according to the invention, the non-stick coating agent is applied to the surface once or several times, preferably to a dry film thickness in the range of 1 to 5 mm. Particularly preferably, the non-stick coating agent is sprayed onto the surface.

[0040] The applied non-stick coating can be dried either at room temperature (20°C) or at an elevated temperature in the range of 150°C to 250°C. Depending on the temperature used, the drying time can be 24 hours (room temperature) or 30 to 60 minutes (150°C to 250°C).

[0041] The equipment obtained by the process with a correspondingly treated surface and improved with regard to non-stick properties is also encompassed by the present invention.

[0042] For the purposes of original disclosure, it is pointed out that all features as they become apparent to a person skilled in the art from the present description and the claims, even if they were specifically described only in conjunction with certain other features, can be combined both individually and in any combination with other features or groups of features disclosed herein, unless this has been expressly excluded or technical circumstances make such combinations impossible or pointless. A comprehensive, explicit presentation of all conceivable combinations of features is omitted here solely for the sake of brevity and readability of the description.

[0043] Furthermore, it should be noted that it is obvious to those skilled in the art that the following exemplary embodiment serves merely as an example of a possible embodiment of the present invention. Those skilled in the art will therefore readily understand that all other embodiments that have the inventive features or combinations of features recited in the claims are also within the scope of protection of the invention. A comprehensive, explicit presentation of all conceivable embodiments within the scope of protection of the claims is omitted here solely for the sake of brevity and readability of the description.

[0044] Example

[0045] This example describes the use of the non-stick coating agent according to the invention to improve the non-stick properties of a used pan with a conventional ceramic coating (GREBLON CK2). The non-stick coating agent used had the following composition:

[0046] 11.0 wt.% silicone oil

[0047] 25.0% by weight methyltriethoxysilane

[0048] 23.0 wt% isopropanol

[0049] 0.3 wt% acetic acid

[0050] 40.7 wt% distilled water

[0051] Before treatment, the pan was thoroughly cleaned and dried. The pan was then sprayed thinly with the non-stick coating agent until fine droplets were evenly distributed over the surface. After a brief contact time of 60 seconds, the droplets were evenly distributed over the surface with a dry cloth and rubbed in. After a waiting time of 10 minutes, the pan was then baked for 30 minutes at a convection temperature of 100°C, 150°C, or 220°C. The pan treated in this way was compared with an untreated new pan and an untreated used pan in the household goods use test (test standard ST115) and the egg-baking test (test standard ST055).

[0052] The household goods use test (test standard ST115) comprises a total of 10 individual tests in the following categories: cross-cut test with 10 adhesive tape tears, egg-baking test, sugar test, boiling test, detergent test, abrasion test followed by a milk burn-in test. Depending on the results, 0 to 10 points are awarded, resulting in a maximum score of 100.

[0053] The egg-baking test (test standard ST055) was conducted after a temperature load of 350°C for 30 minutes. Five eggs were tested, each for 110 seconds at 180°C + / -10°C. Scores range from 0 to 10 depending on the egg's performance.

[0054] The results of the household goods use test (test standard ST115) and the egg baking test (test standard ST055) are presented in the table below. a) Household goods use test b) Egg-baking test

[0055] The coating structure obtained through the treatment meets the food contact requirements according to Regulation EC 1935 / 2004 and, with regard to the tested parameters, complies with the requirements of Section 31 of the German Food and Feed Code (LFGB) for the production of coatings for frying, cooking, and baking appliances, as well as thermally controlled small electrical appliances. When used as intended, the coating can be heated to temperatures up to 230°C, and briefly (15 minutes) to 250°C.

Claims

PATENT CLAIMS 1. Non-stick coating agent for improving the non-stick properties of surfaces, characterized in that the non-stick coating agent contains the following components 5 to 15 wt.% silicone oil, 15 to 35 wt.% methyltriethoxysilane, 10 to 30 wt.% C2-C6 alkanol, < 1 wt.% C1 -C4 alkane acid and The remainder being water, wherein the non-stick coating agent has a dynamic viscosity of < 3500 mPas.

2. The non-stick coating agent according to claim 1, characterized in that the silicone oil component has a dynamic viscosity of > 100 mPas.

3. Non-stick coating agent according to one of claims 1 and 2, characterized in that the silicone oil component consists of 40 to 60 wt.% hydroxy-functional silicone oil.

4. Non-stick coating agent according to one of claims 1 to 3, characterized in that the C2-C6 alkanol component consists of 60 to 100 wt.% propanol, preferably isopropanol.

5. Non-stick coating agent according to one of claims 1 to 4, characterized in that the C1-C4 alkanoic acid component consists of 60 to 100 wt.% acetic acid.

6. Non-stick coating agent according to one of claims 1 to 5, characterized in that it is in the form of a non-stick coating agent spray, which is preferably contained in a container with a spray device.

7. Use of a sprayable non-stick coating agent according to any one of claims 1 to 6 for improving the non-stick properties of a surface of a cooking, baking or roasting utensil or of a small electrical appliance.

8. Use according to claim 12, characterized in that it is an unused cooking, baking or roasting utensil or small electrical appliance.

9. Use according to claim 13, characterized in that it is a used cooking, baking or roasting utensil or small electrical appliance.

10. A method for improving the non-stick properties of equipment for preparing food, characterized in that a non-stick coating agent according to one of claims 1 to 6 is applied to a surface of a cooking, baking or roasting utensil or a small electrical appliance and then dried.

11. A method according to claim 10, characterized in that the non-stick coating agent is applied to the surface to a dry film thickness in the range of 1 to 5 mm.

12. Method according to one of claims 10 or 11, characterized in that the non-stick coating agent is sprayed onto the surface.

13. Method according to one of claims 10 to 12, characterized in that after the application of the non-stick coating agent to the surface, drying is carried out for a period of at least 30 minutes at at least 20°, preferably at a temperature in the range of 150°C to 250°C.

14. A method according to any one of claims 10 to 13, characterized in that the surface to which the non-stick coating agent is applied consists of stainless steel, cast iron, enamel or a conventional non-stick coating.

15. Cooking, baking or roasting utensils or small electrical appliance with a surface having a coating obtained by applying a non-stick coating agent according to one of claims 1 to 6, preferably by applying it by a method according to one of claims 10 to 14.

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