RU2799553C1 - Fluorinated, alkoxysilil functionalized polymer for non-soiled and non-scratch coatings - Google Patents

Abstract

FIELD: fluorinated polymers for coatings.

SUBSTANCE: fluorinated polymer with alkoxysilyl functional groups is proposed, obtained using a method comprising the steps of: a) reacting an OH-functional (per)fluoropolyether (PFPE) with a polyisocyanate under reaction conditions for forming urethane to obtain an isocyanate-functional intermediate B, b) reacting the intermediate B with a secondary alkoxysilyl functional monoamine C to obtain an alkoxysilyl functional polymer. A coating composition containing a fluorinated polymer, a method for coating a substrate using it, and a coated substrate are also proposed.

EFFECT: proposed polymer is used as an additive in the preparation of a coating with easy clean, stain and scratch resistance properties that can be advantageously used to coat various substrates in consumer electronics or automotive applications such as glass, metal, metal alloy, anodized substrates, plastics, composite. etc.

12 cl, 1 dwg, 2 tbl, 3 ex

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to an alkoxysilyl-functional fluorinated polymer useful in the preparation of anti-stain and anti-scratch coating compositions. These coatings are especially useful in the field of consumer electronics or automotive coatings.

BACKGROUND OF THE INVENTION

In the field of consumer electronic devices such as cell phones, tablets, laptops, as well as in automotive interiors, various substrates such as glass, metals, plastics, composites, etc. are used. It is often desirable to coat these substrates with easy to clean, stain and scratch resistant coatings. Easy to clean means that the surface repels water, oil and/or dirt. Easy clean coatings reduce or eliminate the need for surface cleaning.

It is known in the art that fluorinated polymers, in particular (per)fluoropolyether (PFPE), have non-tacky and lubricating properties and can be used to provide easy-to-clean and smudge-resistant coatings. However, such resins are only soluble in fluorinated solvents and thus are difficult to use in coating formulations without the use of special solvents. Another problem with PFPE-based polymers is that they generally do not have good soil and scratch resistance.

There is a need to provide stain-resistant coating compositions that are also durable and at the same time scratch-resistant. In addition, it is desirable that the coating adhere well to various substrates used in consumer electronics and the automotive industry, such as glass, metal, metal alloys, anodized substrates, plastics, composites, etc.

SUMMARY OF THE INVENTION

In order to satisfy the above desires, the present invention provides in a first aspect an alkoxysilyl-functional fluorinated polymer, which can be obtained by a process comprising the steps of:

a) reacting an OH-functional (per)fluoropolyether (PFPE) with polyisocyanate A under urethane reaction conditions to give isocyanate-functional intermediate B,

b) reacting intermediate B with a secondary alkoxysilyl functional monoamine C to form an alkoxysilyl functional polymer.

In a further aspect, the present invention provides a coating composition comprising an alkoxysilyl-functional fluorinated polymer according to any one of paragraphs. 1-5 of the claims, and/or a fluorinated silicone resin obtained by hydrolysis of the same polymer, and additionally a fluorine-free silicone resin.

The present invention also provides a method for coating a substrate, comprising applying a coating composition according to the present invention to a substrate and curing the coating composition.

In another aspect, the present invention provides a coated substrate obtained in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1(a) shows an uncoated glass substrate (top) and a coated glass substrate in accordance with the present invention (bottom).

Fig. 1(b) shows the same as FIG. 1(a), but after wiping with a cloth.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an alkoxysilyl-functional fluorinated polymer. This polymer is based on (per)fluoropolyether (PFPE) and contains alkoxysilyl groups at the ends of the polymer chain.

The alkoxysilyl-functionalized fluorinated polymer according to the present invention can be produced by a process comprising the steps of:

a) reacting an OH-functional (per)fluoropolyether (PFPE) with polyisocyanate A under urethane reaction conditions to give isocyanate-functional intermediate B,

b) reacting intermediate B with a secondary alkoxysilyl functional monoamine C to form an alkoxysilyl functional polymer.

Stage (a)

In step (a), the OH-functional (per)fluoropolyether is reacted with a molar excess of polyisocyanate A to form the isocyanate-functional intermediate B.

(Per)fluoropolyethers (PFPE) are fluorinated polymers containing a straight or branched fully or partially fluorinated polyoxyalkylene chain that contains repeating units having at least one catenary ether bond and at least one fluorocarbon functional group. PFPE can be divided into non-functional and functional; the former contain a PFPE chain, the ends of which have (per)haloalkyl groups, and the latter contain a PFPE chain, having at least two ends, with at least one end containing a functional group. Functional PFPEs, in particular mono- and bifunctional PFPEs, comprise a bi-terminal PFPE chain in which one or both ends carry a functional group. In some embodiments, it may be preferable to use a bifunctional PFPE. In other embodiments, a monofunctional PFPE is used. In addition, in the synthesis step (a), mixtures of mono- and bifunctional PFPEs can be used.

The PFPE used in the present invention is OH-functional, which means that at least one end of the polymer chain has a hydroxyl group (ending in hydroxyl). The end group can also be -CH ₂ OH. OH-functional PFPE preferably has either monohydroxy end groups (PFPE monohydric alcohols) or dihydroxy end groups (PFPE diols). In the case of monohydroxy functionality, the other end preferably has a fully fluorinated group, for example -CF ₃ .

The OH-functional (per)fluoropolyether preferably has a number average molecular weight of 400 to 4000. The Mn value can be determined by gel permeation chromatography (GPC) using a polystyrene standard with tetrahydrofuran as the mobile phase.

The dihydroxy-functional (per)fluoropolyether may have the general structure HO-(CF ₂ -CF ₂ -O) _n -OH or HO-(CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m -OH. It may also include blocks with ethylene oxide units and have the general structure:

HO-(CH ₂ CH ₂ O) _p -CH ₂ -CF ₂ -R _f -CF ₂ -CH ₂ -(OCH ₂ CH ₂ ) _q -OH,

where p and q are integers independently selected in the range of 0-50, preferably 1-50, R _f is a bifunctional radical having the structure of (per)fluoropolyether (CF ₂ CF ₂ O) _n , (CF ₂ O) _m or ( CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m , and n and m are integers independently selected in the range 1-100. When both p and q are non-zero, the resulting polymer has better water dispersibility. Preferably p is in the range of 1-5 and q is in the range of 1-5. Instead of the -OH group, the -CH ₂ OH group can also be used.

Hydroxyl terminated (per)fluoropolyethers are commercially available from Solvay, eg Fluorolink® PFPE or Fomblin® PFPE such as Fluorolink® 5174X, Fluorolink® E10H, Fluorolink® PEG45. Examples of commercially available monohydroxy terminated PFPEs (PFPE monohydric alcohols) include PFPE1600 and PFPE3200 from Tianjin Changlu Flurochemicals and PFPE AL-2 and PFPE AL-4 from Chemours.

Polyisocyanate A is a compound with reactive isocyanate groups and has an isocyanate functionality of at least 2. Diisocyanates are preferably used. Mixtures of polyisocyanates can also be used. The polyisocyanate may be aliphatic, cycloaliphatic or aromatic. Examples of suitable polyisocyanates include hexamethylene diisocyanate (HDI), 2,2,4- and/or 2,4,4-trimethylhexamethylene diisocyanate, p- and m-tetramethylxylene diisocyanate, methylene bis(4-cyclohexyl isocyanate) (hydrogenated MDI), 4, 4-methylene diphenyl isocyanate (MDI), p- and m-phenylene diisocyanate, 2,4- and/or 2,6-tolylene diisocyanate (TDI) and their additives, as well as isophorone diisocyanate (IPDI). Preferred polyisocyanates include aliphatic diisocyanates such as IPDI and HDI. More preferably, cycloaliphatic diisocyanates such as IPDI are used.

The reaction in step (a) is performed under reaction conditions for forming a urethane. Reaction conditions for forming a urethane compound are known to those skilled in the art. The reaction temperature may be in the range of 40-160°C, preferably in the range of 50-100°C. Conventional catalysts such as dibutyltin dilaurate (DBTDL), stannous octoate, diazobicyclo(2,2,2)octane (DABCO), Zn ACAC, tin octoate can be used. The amount of catalyst is preferably 0.005 to 1 ppm. per 100 m.h. urethane-forming monomers.

Reaction (a) preferably takes place in an organic solvent or mixture of solvents. Any suitable solvent that does not react with the reagents can be used. Examples include esters (such as ethyl acetate, propyl acetate), aromatic solvents (such as toluene), ketone solvents (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol); aliphatic hydrocarbons; ethers (such as diethyl ether, tetrahydrofuran), as well as mixtures thereof. Preferred organic solvents include n-butyl acetate, N-methylpyrrolidone, toluene, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), methoxypropyl acetate (PMA), or mixtures thereof.

The reaction in step (a) is preferably carried out in a molar excess of polyisocyanate A. As a result, intermediate B formed in this reaction is isocyanate-functional and can be used in the next reaction step. The molar ratio of PFPE to polyisocyanate A is preferably 1:1 to 3:1.

Intermediate B preferably has a number average molecular weight of 400 to 4000, more preferably 500 to 3000. The Mn value can be determined by gel permeation chromatography (GPC) using a polystyrene standard with tetrahydrofuran as the mobile phase. Intermediate B preferably has no carboxyl functionality. Intermediate B is also preferably free of -OH functionality.

Step (b)

In step (b), an isocyanate-functional intermediate B is reacted with a secondary alkoxysilyl-functional monoamine C to obtain an alkoxysilyl-functional polymer in accordance with the present invention.

Alkoxysilyl-functional monoamine C is a secondary aminosilane with one nitrogen atom, in which the nitrogen atom is replaced by two identical or different groups, at least one of which has the functionality of alkoxysilyl. The present inventors believe that the use of secondary aminosilanes in the preparation of the final polymer improves the stain and scratch resistance characteristics of the polymer-containing coating compared to virgin aminosilanes.

In some embodiments, it is preferred that both groups attached to the nitrogen atom of aminosilane C have alkoxysilyl functional groups. Such compounds may also be referred to as (bis-silyl)amines. In other embodiments, only one of the two substituent groups contains alkoxysilyl functional groups.

Suitable (bis-silyl)amines may have the following general formula:

HN-(Y-Si-(OR ₁ ) _x (R ₂ ) _3-x ) ₂ (I)

where Y is a covalent bond or a C1-C10 alkylene difunctional saturated group, R ₁ and R ₂ are independently a C1-C3 alkyl group, and x is an integer from 0 to 3. Y is preferably a C1-C4 alkylene group , more preferably ethylene or propylene. R ₁ and R ₂ are preferably a C1-C3 alkyl group, more preferably a methyl or ethyl group.

Examples of aminosilanes with two alkoxysilane functional groups include bis-(2-trimethoxysilylethyl)amine, bis-(2-triethoxysilylethyl)amine, bis(3-triethoxysilylpropyl)amine (available under the trade name Dynasylan® 1122 from Degussa), bis( 3-trimethoxysilylpropyl)amine (available under the tradename Dynasylan® 1124 from Degussa) and bis(4-triethoxysilylbutyl)amine. Preferably (bis-silyl)amine C is bis[3-(trialkoxysilyl)propyl]amine, more preferably bis[3-(trimethoxysilyl)propyl]amine.

Examples of single alkoxysilane functional aminosilanes include N-(n-butyl)-3-aminopropyltrimethoxysilane (available under the tradename Dynasylan® 1189 from Degussa), N-(n-butyl)-3-aminopropyltriethoxysilane, N-cyclohexyl-3 -aminopropyltrimethoxysilane (available under the tradename Geniosil® GF 92 from Wacker Chemie), N-cyclohexyl-3-aminopropyltriethoxysilane, N-cyclohexylaminomethylmethyldiethoxysilane (available from Wacker Chemie under the tradename Geniosil® XL 924), N-cyclohexylaminomethyltriethoxysilane (available from Wacker Chemie). Wacker Chemie under the tradename Geniosil® XL 926) and N-phenylaminomethyl-trimethoxysilane (available from Wacker Chemie under the tradename Geniosil® XL 973). They are also suitable in the present invention, although they may be less preferred.

The reaction in step (b) is preferably carried out in an organic solvent or solvent mixture. Suitable solvents are the same as those mentioned above for the reaction in step (a). Preferably, neither diamines nor diols are present during the synthesis, as their use will undesirably increase the molecular weight of the polymer.

The progress of the reaction in step (b) can be followed by analyzing the NCO content over time. The reaction is stopped when the NCO content is no longer detectable.

The resulting alkoxysilyl-functional polymer contains urethane bonds. This polymer preferably has a weight average molecular weight Mw in the range of 2000-20000, more preferably in the range of 4000-15000. This polymer preferably has a number average molecular weight Mn in the range of 1000-8000, more preferably in the range of 2000-6000. This molecular weight allows the use of the alkoxysilyl functional polymer as a (soluble) additive in solvent based systems.

The resulting polymer preferably has neither carboxyl nor hydroxyl groups. Therefore, the acid number is preferably less than 5 mg KOH/g, more preferably 0 mg KOH/g. The acid number can be measured by potentiometric titration, for example according to DIN EN ISO 3682. Preferably, the resulting polymer does not have the OH functional group. The hydroxyl value is preferably <5 mg KOH/g, more preferably 0 mg KOH/g. The hydroxyl number can be measured by potentiometric titration using the TSI method, for example according to ASTM E1899-08.

The alkoxysilyl functionality of the resulting polymer can be hydrolyzed in water or alcoholic solvents, optionally in the presence of a silanol condensation catalyst.

The resulting polymer or the fluorine-containing silicone resin obtained by its hydrolysis can be advantageously used in the preparation of coating compositions, in particular as an additive to a fluorine-free silicone resin.

Coating composition

In another aspect, the present invention provides a coating composition comprising the above-described alkoxysilyl-functional fluorinated polymer and/or its hydrolyzed product (fluorinated silicone resin) together with a fluorine-free silicone resin.

The coating composition preferably contains a fluorinated silicone resin, which can be obtained by hydrolysis of the above-described alkoxysilyl-functional fluorinated polymer, and a fluorine-free silicone resin.

The fluorinated silicone resin can be obtained by hydrolyzing the alkoxysilyl functional group of the above polymer in water and/or alcohol solvents. Preferably an alcohol or a mixture of alcohols is used. Suitable alcohols include, for example, methanol and ethanol. A mixture of water and alcohol (or a mixture of alcohols) may also be used.

Optionally, the hydrolysis is carried out in the presence of a silanol condensation catalyst. Such catalysts are known to those skilled in the art.

Suitable catalysts are, for example, metal salts (eg zirconium nitrate, aluminum chloride), organometallic compounds, in particular organotin compounds (eg dibutyltin dilaurate, dibutyltin acetoacetonate), acids and bases such as tertiary amines (eg triethylamine, triethyleneamine or 2,2 '-diazabicyclo[2.2.2]octane (DABCO)). By acids are meant both Brønsted acids and Lewis acids. Examples of acid catalysts include sulfonic acids and their derivatives, such as methanesulfonic acid, 1-propanesulfonic acid, 1-pentanesulfonic acid, dodecylbenzenesulfonic acid, and p-toluenesulfonic acid, for example. In some embodiments, it may be preferable to use an acid catalyst, in particular a sulfonic acid or a derivative thereof, in particular p-toluenesulfonic acid.

The fluorine-free silicone resin can be obtained by hydrolysis of the fluorine-free silane D. Preferably, the hydrolysis can be carried out in situ during preparation of the coating composition.

The fluorine-free silane D is preferably an alkoxy-functional silane. Optionally, it may further contain another functional group such as an amino group or an epoxy group. In some embodiments, the implementation of the alkoxy functional silane does not contain amine functional groups. Examples of such silanes include methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), phenyltrimethoxysilane (PTMS), phenyltriethoxysilane (PTES), bis[trimethoxysilylpropyl]ethane (BTES), methacryloxypropyltrimethoxysilane (MAPTS), mercaptopropyltrimethoxysilane (MPTES), tetraethyl orthosilicate (TEOS), tetramethylorthosilicate (TMOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS).

In some embodiments, the fluorine-free silane D is an alkoxy-functional aminosilane, such as primary or secondary aminosilanes. Primary alkoxy functional aminosilanes may have the following general formula:

NH ₂ -X ₃ -Si (R ₃ ) _y (OR ₄ ) _3-y (II)

where X ₃ is a covalent bond or a C1-C10 alkylene difunctional saturated group, R ₃ and R ₄ are independently a C1-C3 alkyl group, and y is an integer from 0 to 3. X ₃ is preferably a difunctional alkyl group C1-C4, more preferably propylene or butylene. R ₃ and R ₄ are both preferably ethyl groups. The alkoxyfunctional aminosilane may be, for example, N-(monoalkoxysilylalkyl)amine, N-(dialkoxysilylalkyl)amine or N-(trialkoxysilylalkyl)amine. As alkoxy groups, methoxy and ethoxy groups are preferred, ethoxy groups are particularly preferred. In one preferred embodiment, the alkoxy-functional aminosilane is N-(triethoxysilylpropyl)amine, also known as (3-aminopropyl)triethoxysilane (APTES).

The secondary aminosilanes may be the same as for the secondary alkoxysilyl functional monoamine C described above.

In some embodiments, it may be preferable to use a mixture of aminosilanes and non-aminosilanes.

The hydrolysis of silane D can be carried out in the presence of water and/or an alcoholic solvent(s) such as those described above for the hydrolysis of a fluorinated alkoxysilyl functional polymer. Optionally, silanol condensation catalysts such as those described above can be used.

In some embodiments, it may be preferable to hydrolyze both the alkoxysilyl-functional fluorinated polymer and the fluoro-silane-free polymer D in situ during preparation of the coating composition. In other embodiments, it may be advantageous to carry out the hydrolysis separately and then mix the resulting fluorinated and non-fluorinated silicone resins.

Accordingly, the coating composition can be prepared by mixing the above-described fluorinated alkoxysilyl functional polymer and silane D in the presence of water and/or an alcoholic solvent, preferably an alcohol or a mixture of alcohols. Alternatively, the coating composition can be prepared by mixing fluorinated and non-fluorinated siloxane resins that have been prepared separately.

The coating composition preferably contains 0.1-50 wt.% fluorinated silicone resin based on the total weight of the coating composition.

The coating composition preferably contains 50-99.9% by weight of a fluorine-free silicone resin based on the total weight of the coating composition.

Without wishing to be bound by any particular theory, the inventors of the present invention believe that the use of a non-fluorinated silicone resin in the same formulation results in a higher cross-link density after curing, resulting in a denser coating. As a result, the cured coating will have better wear and stain resistance. In addition, it is believed that the use of both fluorinated and non-fluorinated silicone resins in the same compositions leads to delamination during the curing process and separation of the resins into different layers or regions. This could lead to better compatibility of the coating composition with various substrates, such as glass, inorganic, metal and ceramic substrates.

In addition to the resins described above, other binder resins such as polyurethanes, polyethers, polyesters and polyacrylates may also be present in the coating composition.

The coating composition is preferably solvent soluble. Organic coating compositions contain an organic solvent or a mixture of organic solvents as the main liquid phase in the preparation and/or application of the coating composition. "Main liquid phase" means that organic solvents make up at least 50 wt.% of the liquid phase, preferably at least 80 wt.%, more preferably at least 90 wt.%, and in some embodiments, even 100 wt.% . Compared to waterborne coating compositions, solventborne compositions are believed to perform better in certain properties such as scratch resistance.

The coating composition preferably contains 10-70 wt.%, more preferably 20-60 wt.% organic solvents based on the total weight of the coating composition.

Examples of suitable organic solvents include alcohols (such as ethanol, isopropanol, n-butanol, n-propanol), esters (such as ethyl acetate, propyl acetate), aromatic solvents (such as toluene), ketone solvents (such as acetone, methyl ethyl ketone , methyl isobutyl ketone, cyclohexanone, diacetone alcohol); aliphatic hydrocarbons; chlorinated hydrocarbons (such as CH ₂ Cl ₂ ); ethers (such as diethyl ether, tetrahydrofuran, propylene glycol monomethyl ether), and mixtures thereof. Preferred organic solvents include butyl acetate, N-methylpyrrolidone, toluene, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), propylene glycol monomethyl ether and methoxypropyl acetate (PMA), or mixtures thereof.

The solids content of the coating composition according to the present invention may range from 1 to 90% by weight, preferably 5-65% by weight, more preferably 10-50% by weight.

The coating composition may additionally contain conventional additives such as fillers, antioxidants, matting agents, pigments, rub-resistant particles, flow regulators, surfactants, plasticizers, adhesion promoters, thixotropic agents, light stabilizers, etc.

The present invention also provides a method for coating a substrate, comprising applying a coating composition according to the present invention to a substrate and curing the coating composition.

The coating composition can be applied to a wide variety of substrates by conventional means, including spraying, rolling, scraping, pouring, brushing or dipping.

The coating composition is preferably thermally curable. Curing is preferably carried out at an elevated temperature, for example in the range of 40-190°C, more preferably 50-150°C. The curing temperature can be selected depending on the substrate. Suitable curing temperatures are known to those skilled in the art. Conventional heating methods can be used, such as placing in an oven.

The coating composition of the present invention can be applied to a wide variety of substrates including metallic and non-metallic substrates such as glass, metal, metal alloys, anodized substrates, plastics, composite, etc. Suitable substrates include polycarbonate/acrylonitrile butadiene styrene (PC/ABS), polycarbonate, polyacrylate, polyolefin, polyamide, polystyrene, glass, wood, stone, aluminium, anodized aluminium, aluminum alloys, magnesium aluminum alloy, copper, and carbon fiber reinforced polymer/plastic (CFRP). Preferably the substrate is glass or aluminum.

The coating composition according to the present invention can be used as a single layer applied directly to the substrate, or in multi-layer systems, for example as a primer, base or clear coat.

The coating composition according to the present invention can be used in various coating industries such as consumer electronics, automotive, packaging, wood floors and furniture, home appliances, glass and windows, sports equipment.

The present invention further provides a substrate coated with a coating obtained from the coating composition of the present invention. Coatings in accordance with the present invention have exceptionally good overall properties, including adhesion and scratch resistance. In addition to this, these coatings also have excellent easy-to-clean and stain-resistance properties, which can be tested with a permanent marker and chemicals.

Examples

Hereinafter, the present invention will be described with reference to the following examples. All parts and percentages are by weight unless expressly stated otherwise.

Fluorolink® E10-H is an ethoxylated double alcohol perfluoropolyether manufactured by Solvay, NMR: 1700 amu, kinematic viscosity at 20°C: 115 cSt.

Dynasylan® 1124 - bis(trimethoxysilylpropyl)amine from Evonik

IPDI - isophorone diisocyanate

DBTDL - dibutyltin dilaurate

MIBK - methyl isobutyl ketone

BAC - butyl acetate

PMA - methoxypropyl acetate

Example 1 Synthesis of Fluoride Additive

First, 60 g of Fluorolink® E10-H was added dropwise to 15 g of IPDI with 0.05 g of DBTDL at 60°C for about 1 hour. After half of the isocyanate had reacted, 25 g of Dynasylan® 1124 and 50 g of BAC were added dropwise to the reaction mixture over a period of approximately 30 minutes. The reaction was then continued until free NCO was no longer detectable.

Example 2: Anti-Fingerprint Coating

First, 80 g of Dynasylan® 1124 in 80 g of BAC were hydrolyzed with 3.6 g of water and 70 g of ethanol for about 3 hours at room temperature. Then, 1 g of the fluorine additive prepared in Example 1 and another 250 g of BAC were added to the reaction system. The reaction continued for approximately 2 hours and the product was collected after filtration through 25 µm filter paper.

Example 3: Coating Characteristics

The glass substrate was treated with plasma. The anti-fingerprint coating composition prepared in Example 2 was sprayed onto glass and aluminum substrates to a dry film thickness of 2-4 µm. The samples were cured at 150°C for 30 minutes and then kept at room temperature for continuous curing for 5 days.

Static contact angle, pencil hardness and coating adhesion were measured. The static contact angle was measured over the cured coatings, respectively, by the quiescent drop method. The droplets had a volume of 3 μl and the measurement temperature was approximately 20°C. Contact angles were measured using a DataPhysics instrument with SCA 20 software. Pencil hardness was measured according to a standard pencil test (9B to 9H hardness). Adhesion was measured using a tape test in accordance with ASTM D3359-02. The adhesion test result can vary from 0B - the worst result (more than 65% of the transverse notch area is removed with tape) to 5B - the best result (0% of the transverse notch area is removed).

The results are shown in Table 1.

Table 1. Surface properties

Static contact angle/° - water 108~111 - diiodomethane 85~88 - ethylene glycol 94~97 Pencil hardness (on glass) 9H Pencil hardness (on aluminum) 2H Adhesion (on glass) 5B Adhesion (on aluminum) 5B

Easy cleaning properties

Easy clean properties were tested by writing the word "stain" on the coated substrate with a ZEBRA black ink permanent marker.

Fig. 1(a) shows in the upper half the uncoated glass substrate and in the lower half the substrate coated with the coating prepared in Example 2.

Fig. 1(b) shows the same substrates as in FIG. 1(a), but after wiping off the ink with a cloth.

It can be seen that the black ink does not shrink on the uncoated glass substrate (FIG. 1(a), top half). In contrast, black ink is compressed into beads on the surface of the coating according to the present invention (FIG. 1(a), lower half). This means that the coated surface according to the present invention has ink repellent properties.

After wiping (FIG. 1(b), bottom half), the coated surface according to the present invention remains clean and shows no ink residue. It is not possible to erase ink from uncoated glass (Fig. 1(b), upper half). This demonstrates the easy cleaning properties of the coating according to the present invention.

Abrasion of wood by steel

Abrasion resistance was tested using the 5750 Linear Abraser (TABER®). The test was performed with a load of 0.5 or 1 kg on #0000 steel wool applied to a coated panel (friction area 1 cm x 1 cm). The abrasion rate was set to 60 cycles/min, distance 60 mm. After the test, the contact angle with water (WCA) was again measured. The results are shown in Table 2.

Table 2.

WCA before the test WCA after the test 1000T/500g 108-111° 105-107° 2000T/500g 108-111° 100-105° 3000T/500g 108-111° 95-101° 1000T/1kg 108-111° 95-105°

As can be seen from Table 2, the water contact angles did not decrease significantly after the test. This means that the coating has largely retained its dirt-resistant and easy-to-clean properties.

Claims (16)

1. Fluorinated polymer with alkoxysilyl functional groups for obtaining a coating obtained by a method comprising the steps: a) reacting an OH-functional (per)fluoropolyether (PFPE) with polyisocyanate A under urethane reaction conditions to form an isocyanate-functional intermediate B, b) reacting intermediate B with a secondary alkoxysilyl functional monoamine C to form an alkoxysilyl functional polymer. 2. The polymer of claim 1, wherein the OH-functional (per)fluoropolyether is a hydroxyl-terminated PFPE or a hydroxyl-terminated PFPE. 3. The polymer according to claim 2, wherein the PFPE with two hydroxyl end groups has the general structure HO-(CH ₂ CH ₂ O) _p -CH ₂ -CF ₂ -R _f -CF ₂ -CH ₂ -(OCH ₂ CH ₂ ) _q -OH, where p and q are integers independently selected in the range 0-50, R _f is a bifunctional radical having the structure of perfluoropolyether (CF ₂ CF ₂ O) _n , (CF ₂ O) _m or (CF ₂ -CF ₂ -O) _n -(CF ₂ -O) _m and n and m are integers independently selected in the range 1-100. 4. The polymer according to any one of paragraphs. 1-3, in which polyisocyanate A is a cycloaliphatic diisocyanate. 5. The polymer according to any one of paragraphs. 1-4, wherein the secondary, alkoxysilyl functional monoamine C is bis[3-(trialkoxysilyl)propyl]amine. 6. Soluble coating composition containing a fluorinated polymer with alkoxysilyl functional groups according to any one of paragraphs. 1-5 and/or a fluorinated silicone resin obtained by hydrolysis of the same polymer and additionally a fluorine-free silicone resin. 7. The coating composition according to claim 6, wherein the fluorine-free silicone resin is obtained by hydrolysis of the fluorine-free silane D. 8. Coating composition according to claim 7, wherein the fluorine-free silane D is selected from alkoxysilanes, alkoxyfunctional aminosilanes, and mixtures thereof. 9. The method of coating the substrate, including applying the coating composition according to any one of paragraphs. 6-8 onto the substrate and curing the coating composition. 10. Coated substrate to prevent contamination and scratching of the product, obtained in accordance with the method according to paragraph 9. 11. The substrate according to claim 10, which is selected from glass, metal, metal alloys, anodized substrates, plastics and composite. 12. The substrate according to claim 11, which is selected from the group consisting of polycarbonate / acrylonitrile butadiene styrene (PC / ABS), polycarbonate, polyacrylate, polyolefin, polyamide, polystyrene, polyamide, glass, wood, copper, aluminum, anodized aluminum, aluminum alloys, magnesium aluminum alloy, and carbon fiber reinforced polymer/plastic (CFRP).

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