FIELD The application relates to a coating composi tion as defined in claim 1 and to a method for forming a coating as defined in claim 14, as well as to use of the coating composition as defined in claim 18 and to use of the method as defined in claim 19.

BACKGROUND

Different primer materials and coatings that may be used in the treatment and coating of an outer surface of a boat or blades of a wind turbine are known in the prior art. Currently, toxic paints that may dissolve in the water system are used in boat out er surfaces, such as bottom and sides.

OBJECT The object is to disclose a new type of coat ing composition and method for forming a coating, e.g. to an outer surface of a boat or to an outer surface of blades of a wind turbine. A further object is to disclose a new type of coating composition that does not dissolve to the environment from the surface being coated and that is non-toxic and colourless. A further object is to disclose a coating that makes the surface slippery and reduces friction. SUMMARY

The coating composition, the method, and the use of the coating composition and the method are characterized by features set forth in the claims. The coating composition comprises at least a first component, a siloxane-based component and a binder component.

DETAILED DESCRIPTION

The coating composition comprises at least the following components: a first component that com prises polytetrafluoroethylene or a derivative there of, a silicone-based substance or another suitable substance having a low coefficient of friction, a si loxane-based component and a binder component that comprises a polymer dispersion of styrene acrylate. In one embodiment the coating composition is in the form of a dispersion.

In one embodiment the siloxane-based compo nent is a siloxane compound, a silicone-based compound or a corresponding substance. In one embodiment the siloxane-based component is a siloxane or silicone ol igomer compound. In one embodiment the siloxane-based component is alkoxymethylsiloxane. In one embodiment the siloxane-based component is in the form of a dis persion, e.g. in the form of an oil dispersion.

In one embodiment the first component com prises at least polytetrafluoroethylene or a deriva tive thereof, a silicone-based substance or another suitable substance having a low coefficient of fric tion. In one embodiment the first component comprises polytetrafluoroethylene, a derivative thereof, a sili cone-based substance and/or a substance having a low coefficient of friction. In one embodiment the first component comprises polytetrafluoroethylene (PTFE), e.g. teflon, or a derivative thereof. In one embodi ment the first component comprises a substance having a low coefficient of friction. In one embodiment the first component comprises a silicone-based substance, such as silicone, e.g. polysiloxane, or a derivative of silicone. In one embodiment the first component comprises a ceramic. In one embodiment the coefficient of friction of the first component is lower than 0.15, and in one embodiment lower than 0.1.

In one embodiment the first component com prises polytetrafluoroethylene (PTFE), e.g. teflon or equivalent, as a main substance. Alternatively a de rivative of polytetrafluoroethylene or a polytetraflu- oroethylene-based substance suitable for the purpose of use may be used as the main substance of the first component. In one embodiment the first component com prises polytetrafluoroethylene or a derivative there of, and polyisobutylene and/or poly-alpha-olefin has been used as a carrier. In one embodiment the first component of the coating composition consists of A and B components, wherein the A component comprises poly tetrafluoroethylene and polyisobutylene has been used as a carrier and wherein the B component comprises polytetrafluoroethylene and poly-alpha-olefin (PAO) has been used as a carrier. In one embodiment the same substance is used as the main substance of the A and B component. In one embodiment a different substance is used as the main substance in the A and B components.

In one embodiment the first component com prises a silicone-based substance. The silicone-based substance may be silicone or a derivative thereof. In one embodiment the silicone-based substance is a sili cone that is a polysiloxane. In one embodiment the polysiloxane may be any polysiloxane suitable for the purpose of use, e.g. polyethylenesiloxane or polydi- methylenesiloxane . In one embodiment the silicone- based substance is in the form of a dispersion, e.g. an aqueous dispersion.

In one embodiment the coating composition comprises the first component in an amount of 1 - 40 % by weight, in one embodiment 2 - 30 % by weight and in one embodiment 5 - 20 % by weight. In one embodiment the coating composition comprises the first component in an amount of 1 - 20 % by weight, in one embodiment 3 - 15 % by weight, and in one embodiment 5 - 10 % by weight.

In one embodiment the coating composition contains the A component in an amount of 1 - 30 % by weight, in one embodiment 1 - 20 % by weight, and in one embodiment 1 - 10 % by weight. In one embodiment the coating composition contains the B component in an amount of 1 - 30 % by weight, in one embodiment 1 - 20 % by weight, and in one embodiment 1 - 10 % by weight. In one embodiment the coating composition contains the A component in an amount of 1 - 7 % by weight and the B component in an amount of 1 - 7 % by weight.

In one embodiment the coating composition contains the binder component in an amount of 20 - 80 % by weight, in one embodiment 30 - 70 % by weight, in one embodiment 40 - 67 % by weight, and in one embodi ment 50 - 65 % by weight. In one embodiment the coat ing composition contains the binder component in an amount of 57 - 63 % by weight.

In one embodiment the coating composition contains the siloxane-based component in an amount of 10 - 50 % by weight, in one embodiment 10 - 40 % by weight, in one embodiment 15 - 37 % by weight, and in one embodiment 17 - 35 % by weight. In one embodiment the coating composition contains the siloxane-based component in an amount of 20 - 32 % by weight.

In one embodiment the coating composition contains the first component in an amount of 2 - 15 % by weight, the binder component in an amount of 40 - 70 % by weight and the siloxane-based component in an amount of 15 - 40 % by weight. In one embodiment the coating composition contains the first component in an amount of 3 - 12 % by weight, the binder component in an amount of 45 - 68 % by weight and the siloxane- based component in an amount of 17 - 35 % by weight. In one embodiment the coating composition contains the first component in an amount of 5 - 10 % by weight, the binder component in an amount of 50 - 65 % by weight and the siloxane-based component in an amount of 20 - 32 % by weight.

In one embodiment the coating composition is applied onto a desired surface to form a coating. In one embodiment the surface to be coated may be washed, cleaned and/or ground before applying the coating com position. In one embodiment the surface to be coated is roughened or ground before applying the coating composition.

In one embodiment the coating composition ad ditionally comprises a primer substance that is a binder component and that is applied under the coating composition to the surface to be coated when using the coating composition.

In a method embodiment for forming a coating the method comprises the steps of a) applying a binder component that comprises a polymer dispersion of sty rene acrylate onto a surface to be treated as a primer and b) applying over the primer a coating composition that has been described in this specification and that is formed by mixing the components of the coating com position to form the composition. In one embodiment the coating composition is formed by mixing a first component that comprises polytetrafluoroethylene or a derivative thereof, a silicone-based substance or a substance having a low coefficient of friction, a si loxane-based component and a binder component that comprises a polymer dispersion of styrene acrylate.

In one embodiment the siloxane-based compo nent of the coating composition of step b) of the method is selected from a group of: a siloxane com pound, a silicone-based compound or a corresponding substance. In one embodiment the siloxane-based compo nent is alkoxymethylsiloxane. In one embodiment the first component com prises polytetrafluoroethylene or a derivative there of, and polyisobutylene and/or poly-alpha-olefin has been used as a carrier. In one embodiment the first component comprises a silicone-based substance. In one embodiment the first component comprises a substance having a low coefficient of friction.

Application of the primer may be done with a sprayer, a brush or in another suitable way. In one embodiment the primer is allowed to dry at an ambient temperature. In one embodiment the surface to be coat ed may be washed, cleaned and/or ground before apply ing the primer. In one embodiment the surface to be coated is roughened or ground before applying the pri mer. In one embodiment the surface to be coated may be warmed before applying the primer.

In one embodiment, after applying the coating composition the coated surface is warmed to dry the coating. In one embodiment, after applying the coating composition the coated surface is heated.

In one embodiment the coating composition is used in the treatment of an outer surface of a boat or blades of a wind turbine. In addition, the coating composition may also be used in other applications. In one embodiment the method and the coating formed therein are used in the treatment, e.g. coating, of an outer surface of a boat or blades of a wind turbine. In one embodiment the coating composition or the coat ing is used in making a desired surface slippery. Preferably, the desired surface, e.g. a metal surface, is treated with the coating composition to make the surface slippery, to reduce friction of the surface and/or to form a hydrophobic interface.

The coating composition and the coating formed from it provide significant advantages over the prior art. By means of the coating composition and the coating, friction of the coated surface may be reduced and the surface can be made more slippery. The coating composition holds very well to the surface being coat ed, and it does not dissolve to the environment from the coated surface. The coating makes the coated sur- face smooth and makes the surface slippery, and thus reduces friction, such as air resistance or resistance caused by water. In addition, the coating provides a hydrophobic interface in connection with the coated surface, whereby e.g. a hydrophobic film is formed be- tween the coating and a surrounding state of matter such as water. Thereby the surface repels water, and drops of water so to speak roll off the surface. Thus for example a boat glides well in water, whereby the consumption of fuel is also reduced. The coating com- position also prevents very well the adhesion of dirt to the coated surface, which also reduces friction. In addition, the coated surface can be easily washed with water without any chemicals, and possible dirt can be easily removed from the surface. The coating composi- tion can be easily applied to a desired surface to form a coating to that surface.

EXAMPLES

Example 1

In this example a coating composition was formed for use as a coating, for example in the bottom of a boat or blades of a wind turbine. The coating composition comprised a first component and a binder component. The first component of the coating composition consisted of A and B compo nents. The A component (25 % dispersion) comprised polytetrafluoroethylene (PTFE) in an amount of 25 %, and in the A component the carrier was polyisobutyl ene. The B component (30 % dispersion) comprised poly tetrafluoroethylene (PTFE) in an amount of 30 %, and in the B component the carrier was poly-alpha-olefin. The amount of the A component in the coating composi tion was 20 % by weight, and the amount of the B com ponent was 20 % by weight. The binder component con sisted of a polymer dispersion of styrene acrylate, and the amount of the binder component in the coating composition was 45 % by weight. In addition, the coat ing composition contained a siloxane-based component that was alkoxymethylsiloxane (100 %) in an amount of 15 % by weight.

The A component had a specific weight of 1 g/cm ³ and a particle size mean value of 0.4 - 0.8 pm. The B component had a particle size mean value of 0.4 - 0.8 pm and a viscosity of <2000 cps.

Example 2

In this example a coating composition was formed for use as a coating, for example in the bottom of a boat or blades of a wind turbine.

The coating composition comprised a first component and a binder component. The first component of the coating composition consisted of A and B compo nents. The A component (25 % dispersion) comprised polytetrafluoroethylene (PTFE), and in the A component the carrier was polyisobutylene. The B component (30 % dispersion) comprised polytetrafluoroethylene (PTFE), and in the B component the carrier was poly-alpha- olefin. The amount of the A component in the coating composition was 15 % by weight, and the amount of the B component was 15 % by weight. The binder component consisted of a polymer dispersion of styrene acrylate, and the amount of the binder component in the coating composition was 40 % by weight. In addition, the coat ing composition contained a siloxane-based component that was alkoxymethylsiloxane (100 %) in an amount of 30 % by weight. The A component had a specific weight of 1 g/cm ³ and a particle size mean value of 0.4 - 0.8 pm. The B component had a particle size mean value of 0.4 - 0.8 pm and a viscosity of <2000 cps.

Example 3

The coating composition according to Example 2 was used as a coating in the bottom of a boat.

An outer surface, i.e. the bottom, of the boat was treated by applying the binder component, that is a polymer dispersion of styrene acrylate, onto the outer surface of the boat being treated as a pri mer. The binder component was applied for example with a brush or by spraying. Alternatively the binder com ponent could be applied in another desired way. The binder component was allowed to dry at an ambient tem perature. The bottom of the boat was washed, cleaned and/or ground before applying the primer. Over the primer the coating composition according to Example 2 was applied, which coating composition was formed by mixing the constituents to form the coating composi tion.

In tests it was observed that the coating held very well to the bottom of the boat. The boat glided well in water, i.e. friction was reduced, and dirt did not adhere to the bottom of the boat. In ad dition, it was observed that the bottom of the boat was easily washable e.g. by means of a water spray or a pressure washer.

Example 4

In this example, coating compositions were formed for use as a coating in the bottom of a boat. The coating compositions formed were tested in the bottom of a boat at lake Saimaa.

The coating composition comprised a first component, a siloxane-based component and a binder component. The first component of the coating composi tion consisted of two component parts that both con tained polytetrafluoroethylene (PTFE), and in one of them the carrier was polyisobutylene and in the other one the carrier was poly-alpha-olefin. The first com ponent contained an equal amount of both component parts. The siloxane-based component was alkoxyme- thylsiloxane having a siloxane content of 100 %. The binder component was a polymer dispersion of styrene acrylate. The coating composition contained 5 - 10 % by weight of the first component, 20 - 35 % by weight of the siloxane-based component and 55 - 75 % by weight of the binder.

An outer surface or at least part of the out er surface of the boat was treated by applying the binder component, i.e. a polymer dispersion of styrene acrylate, onto the outer surface of the boat being treated as a primer. The binder component was applied for example with a brush or by spraying. The binder component was allowed to dry at an ambient tempera ture. The bottom of the boat was washed and cleaned before applying the primer. The bottom of the boat was slightly roughened by grinding before applying the binder component. Over the primer the above-described coating composition was applied, which coating compo sition had been formed by mixing the constituents to form the coating composition.

In tests it was observed that the coating formed from the coating composition held very well to the outer surface of the boat. It was observed that dirt and slime did not adhere to the parts of the out er surface of the boat that had been treated with the coating composition as described. Correspondingly, dirt and slime adhered very strongly to non-treated parts. When the boat was raised up from water, slime came off and fell down from the parts of the outer surface that had been treated with the coating as de- scribed. However, slime did not fall down from the non-treated parts, and the slime and dirt seemed to have stuck very fast. From the parts of the outer sur face that had been treated with the coating as de scribed it was easy to remove residual dirt by washing with tap water. When the whole bottom of the boat had been treated with the coating as described, the boat glided well in water, i.e. friction was reduced.

Example 5

In this example a coating composition was formed for use as a coating, for example in the bottom of a boat or blades of a wind turbine.

The coating composition comprised a first component, a siloxane-based component and a binder component. The first component of the coating composi tion consisted of a silicone-based substance that was a polysiloxane. The binder component was a polymer dispersion of styrene acrylate. The siloxane-based component was alkokxymethylsiloxane. The coating com position contained 5 - 20 % by weight of the first component, 20 - 35 % by weight of the siloxane-based component and 55 - 75 % by weight of the binder.

The coating composition and the coating are suitable for use as different embodiments in any kinds of applications for forming a coating to a desired surface.

The invention has been described above by way of example without limiting the invention in any way only to the compositions and applications as de scribed. Different embodiments of the invention are possible withing the scope defined by the claims.