EP1414831A1

EP1414831A1 - Fluoroalkyl-modified organosilanes and their use in coating compositions

Info

Publication number: EP1414831A1
Application number: EP02762416A
Authority: EP
Inventors: Christian Meiners; Ralf GROTTENMÜLLER; Helmut Zingerle; Ivan Cabrera
Original assignee: Celanese Emulsions GmbH; Clariant GmbH
Current assignee: Clariant Produkte Deutschland GmbH
Priority date: 2001-08-02
Filing date: 2002-07-31
Publication date: 2004-05-06
Also published as: MXPA04000983A; US20050038150A1; BR0211638B1; JP2004537601A; BR0211638A; WO2003014131A1

Abstract

The invention relates to organosilanes of general formula (I), in which R represents a fluorinated or partially fluorinated alkyl group of formula CnZ2n+1(CH2)m-, where n ≥ 1, m ≥ 1 and Z is either a hydrogen atom or a fluorine atom, with the proviso that at least one Z is a fluorine atom, Y represents a hydrogen atom or alkyl group comprising between 1 and 10 C atoms, X is either a hydrogen atom, a linear or branched alkyl group comprising between 1 and 10 C atoms, a group of formula ROC(O)(CHY)(CH2)-, a phenyl group or a benzyl group, R1 represents a linear or branched alkylene group comprising between 1 and 20 C atoms and R?2, R3 and R4¿ represent linear or branched alkyl groups comprising between 1 and 10 C atoms or linear or branched alkoxy groups comprising between 1 and 10 C atoms, which are linked to the silicon atom by means of the oxygen atom. The invention also relates to a method for producing said organosilanes and to the use thereof, in particular in coating compositions for reducing their tendency to accumulate dirt.

Description

description

FLUORALKY ODIFIZED ORGANOSILANES, USE IN COVERAGE COMPOSITIONS

The present invention relates to fluoroalkyl-modified organosilanes, processes for their preparation and their use, in particular as additives in coating compositions to reduce their tendency to become soiled. The resulting coating compositions also have increased water resistance compared to coatings in which surfactant-like comparative compounds have been incorporated. In addition, the impregnating effect is given even with repeated soiling with dirt dispersions.

It is known that the addition of low molecular weight compounds with

Perfluoroalkyl groups in coating compositions reduce their tendency to soiling.

Dust-repellent color compositions are known from US Pat. No. 4,208,496 which contain ionic emulsifiers of the formula F (CF ₂ ) _n CH ₂ CH ₂ SCr. ₂ CH ₂ COOLi included as a color component. However, these emulsifiers have no functional groups in the molecule which could lead to anchoring in the color film formed.

However, it is also known to be non-chemically covalently bound

Emulsifiers can be easily washed out of coatings. Furthermore, the water resistance of coatings is negatively influenced by non-chemically covalently bound emulsifiers.

Furthermore, low-molecular silane-modified perfluoroalkane compounds of the formula C _n F2n ₊ ι (CH ₂ ) 2Si (OR) 3 are known, such as C ₆ F ₁₃ (CH ₂ ) 2Si (OEt) 3. These compounds are used, among other things, to impregnate mineral Substrates used. The surfaces to be subsequently treated with these compounds must, however, be cleaned before application and the additive may have to be applied repeatedly. This high quality seal against pollution is very expensive due to the high cost of the additive and the multiple operations. The substances are expensive because of their synthesis by hydrosilylation, since noble metal catalysts have to be used.

JP-A-08/109580 describes the production of siloxane compounds containing amino groups for fiber impregnation. A diamine functionalized, oligomeric or polymeric siloxane on (meth) acrylic acid ester is used. added. However, the presence of diamines leads to an increase in

Points of attack for an oxidative degradation of the drug molecule and for increased polarity and hydrophilicity of the compounds.

Similarly, JP-A-09/279049 discloses silicon-containing compounds consisting of silicon group-containing polymers and adducts of diaminosilanes and per- or partially fluorinated alkyl radicals containing ethylenically unsaturated compounds. However, as stated above, the person skilled in the art is aware that diamines, owing to their higher polarity, lead to higher water absorption and higher yellowing, compared to compounds which are otherwise constitutively identical without a second amine group. The yellowing occurs due to oxidative attack on the nitrogen atoms. Furthermore, the complex di- or oligoamines are more expensive to produce than the simple aminosilanes. The presence of at least three free valences on the amino groups for adduct formation also results in a complex product mixture which cannot be worked up in diaminosilanes. The synthesis of a defined substance is therefore not economically possible. The same applies all the more to oligosilanes.

The production of hydrophilic organosilicon compounds by addition of amino groups-containing silanes or (poly) siloxanes with (oligo) hydroxy or Sugar residues modified (meth) acrylates are described in DE-A-198 54 186. Amino-organopolysiloxanes are preferably added to the (meth) acrylic esters. A disadvantage of such additives with hydrophilic residues to reduce the tendency to soiling is their increased water absorption.

Furthermore, the latest studies have shown that the addition of siloxanes to external coating compositions increases their tendency to become contaminated in outdoor weathering rather than reduces it. This is attributed, among other things, to the increased affinity of the hydrophobic dirt components (including soot) for the hydrophobic coating (Q. Wagner in "Farbe und Lack", 2001, 107, 105-134).

It was therefore an object of the present invention to develop additives for coating compositions and polymer dispersions in order to reduce their tendency towards soiling, which are characterized by moderate synthesis and raw material costs and low water absorption of the resulting coating compositions. In addition, the compounds should combine the advantages of both polymeric and low molecular weight additives, namely, on the one hand, they should have a high migration capacity during film consolidation in order to enrich the hydrophobic

Allow groups at the hydrophobic coating / air interface, and on the other hand, the additives should have an increased resistance to washout by rain in the coating, as is achieved by polymeric, fluorine-containing impregnation additives.

The present invention relates to general organosilanes

Formula 1),

where R is a fluorinated or partially fluorinated alkyl radical of the formula CnZ _2n + ι (CH ₂ ) m-, with n> 1, m> 1 and Z either a hydrogen atom or a fluorine atom, with the proviso that at least one Z is a fluorine atom,

Y is a hydrogen atom or alkyl radical with 1 to 10 C atoms, X is either a hydrogen atom, a linear or branched alkyl radical with 1 to 10 C atoms, a radical of the formula ROC (O) (CHY) (CH ₂ ) -, a phenyl - or a benzyl radical,

R ^{1 is} a linear or branched alkylene radical with 1 to 20 C atoms and R ² , R ³ and R linear or branched s alkyl radicals with 1 to 10 C atoms or linear or branched alkoxy radicals with 1 to 10 C atoms, Represent oxygen atom with the silicon atom represent.

Organosilanes of the general formula (I) are preferred, where R is a fluorinated alkyl radical of the formula C _n F ₂ n ₊ ι (CH ₂ ) _m -.

Also preferred are organosilanes of the general formula (I), where n = 1 to 30 and m = 1 to 4.

Also preferred are organosilanes of the general formula (I), where X is a methyl, an ethyl, a propyl, a phenyl or a benzyl radical,

Y is a hydrogen atom or a methyl radical,

R ^{1 is} a - (CH ₂ ) ₃ -, a -CH ₂ CH (CH ₃ ) CH ₂ - or a -C ₂ H4 radical, and

R ² , R ³ , R ^{4 represent} a CH ₃ O, a C ₂ H ₅ O or a CH (CH ₃ ) ₂ θ radical.

Organosilanes of the general formula (I) are particularly preferred, where R is a fluorinated alkyl radical of the formula C _n F2n + ι (CH2) m-, with n = 6 to 14 and m = 2. Alkyl residues of this formula, with n = 6 to 14 and m = 2, form the best compromise between synthesis and raw material costs, (unwanted) tendency to crystallize the fluoroalkane chain and impregnating effect. Are (meth) acrylic acid esters with fluoroalkane residues of the abovementioned fraction containing an ethyl spacer for oxygen-ester bonding as a coupling component used, the resulting fluoroalkylsilanes are liquid at room temperature and are therefore easy to incorporate into coating compositions or latex dispersions.

Organosilanes of the general formula (I) are particularly preferred, where X is an ethyl radical,

Y is a hydrogen atom or a methyl radical, R ^{1 is} a -CH ₂ CH (CH ₃ ) CH ₂ radical and

R ² ; R ³ , R ^{4 represent} a CH ₃ O radical; -, or -

X is a methyl radical,

Y is a hydrogen atom or a methyl radical, R ^{1 is} a - (CH ₂ ) ₃ radical and

R ² , R ³ , R ^{4 represent} a CH ₃ O radical.

The organosilanes according to the invention are both hydrophobic and oleophobic and contain no siloxane groups. The only silicon functionality of the organosilanes according to the invention, the silane group, serves to anchor the hydro- and oleophobic fluoroalkyl group on the substrate.

The present invention further relates to processes for the preparation of the organosilanes according to the invention.

The organosilanes according to the invention are preferably prepared by addition of the ω-aminoalkylsilanes with the amino group to the double bond of the (meth) acrylic acid esters with fluorinated side chain similar to the Michael reaction. (Meth) acrylic acid esters are understood to mean both the esters of acrylic and the esters of methacrylic acid.

The present invention thus also relates to a method for

Production of the organosilanes according to the invention, characterized in that is that a (meth) acrylic ester of the general formula (II) is reacted with an ω-aminoalkylsilane of the general formula (III),

where R is a fluorinated or partially fluorinated alkyl radical of the formula C _n Z2n + ι (CH ₂ ) _m -, with n> 1, m> 1 and Z either a hydrogen atom or a fluorine atom, with the proviso that at least one Z is a fluorine atom,

Y is a hydrogen atom or alkyl radical with 1 to 10 C atoms, X is either a hydrogen atom, a linear or branched alkyl radical with 1 to

10 carbon atoms, a radical of the formula ROC (O) (CHY) (CH ₂ ) -, a phenyl or a

benzyl

R ^{1 is} a linear or branched alkylene radical having 1 to 20 carbon atoms and

R ² , R ³ and R ^{4 are} linear or branched alkyl radicals having 1 to 10 carbon atoms or linear or branched alkoxy radicals having 1 to 10 carbon atoms, which have the

Represent oxygen atom with the silicon atom represent.

The reaction takes place either without solvent or with the addition of water, organic solvents or mixtures thereof. The

The reaction preferably takes place under atmospheric pressure (1 bar), but it can also be carried out under elevated or reduced pressure. Catalysts which accelerate the reaction can also be used.

If a solvent is used in the preparation, the reaction product is either used in the reaction solvent or the solvent used is removed. If necessary, the product obtained can be removed in another solvent after removal of the solvent be dissolved, or dispersed in water or another liquid. Emulsifiers can be used for this.

Another preferred object of the present invention relates to the use of the organosilanes according to the invention, in particular in

Coating compositions, for treating surfaces to reduce their tendency to become soiled.

In addition, the organosilanes according to the invention are also used as anti-blocking agents, in particular in coating compositions (e.g. clearcoats for wood coating) and polymer dispersions. Another object of the present invention thus relates to the use of the organosilanes according to the invention as anti-blocking agents, in particular in coating compositions, for the treatment of surfaces.

It has surprisingly been found that the organosilanes according to the invention as additives in polymer dispersions have blocking resistance, i.e. the resistance to sticking to similarly treated or other surfaces, the resulting coatings significantly increase. For example, in the case of styrene-acrylate dispersions with core-shell morphology, which normally have a moderate blocking resistance in the clear lacquer film on wooden substrates, even the smallest amounts of the organosilanes according to the invention (for example 0.5% by weight) lead to excellent blocking resistance (tendency to block) compared to similarly treated surfaces, determined at 50 ° C and room temperature).

The present invention also relates to the use of the organosilanes according to the invention for the hydrophobization and oleophobicization of surfaces.

The surfaces are preferably coated for all purposes by adding the organosilanes according to the invention in Sprayed substance, solution or dispersion on the surfaces to be treated, dipping the surface in the solution or dispersion of the additives, or applying with a brush or roller, or a coating composition to be applied, containing at least one polymeric binder, in substance, solution or dispersion adds and applies the coating composition to the surface.

The additives according to the invention can also be used as release agents for surfaces.

The present invention also relates to the coating compositions themselves.

Preferred coating compositions are a) at least one polymeric binder, b) at least one organosilane according to the invention, and c) optionally pigments, fillers, dispersants, thickeners, protective colloids, wetting agents, preservatives, algicides, rust protection pigments, UV filter materials, UV initiators and / or contain other auxiliary substances. -. , _, , '

The coating composition here contains the polymeric binder (s) in solution, dispersion or emulsion in liquids or in bulk (the latter, for example, in the case of powder coatings as a coating composition). All polymeric binders known to the person skilled in the art can be used as polymeric binders. Preferred polymeric binders are

Poly (acrylates), poly (styrene acrylates), poly (urethanes), poly (esters), polyester polyols, aminoplasts, epoxy resins, epoxy amine resins, alkyd resins, hybrid dispersions made of poly (styrene acrylates) or poly (acrylates) with poly (urethanes) or alkyd resins. Mixtures of these polymers can also be used.

The organosilanes according to the invention are particularly preferred for reducing the early tendency to dirt in pigment-containing ones Outer coatings with polymeric binders are used that contain UV initiators (such as benzophenone derivatives). The UV initiator can either be contained in the polymeric binder or can be added to the coating composition during its production. Preferred applications of these coatings are, for example, elastic exterior paints and road marking paints.

Coating compositions which additionally contain at least one UV initiator are therefore particularly preferred.

The dirt-repellent organosilanes migrate to the surface of the coating composition or the polymer film and prevent the soft, polymeric binder from sticking to dirt particles until the polymeric binder has hardened on the surface due to the UV initiators. Depending on the solar radiation, a considerable time may pass before the surfaces of the coatings have hardened by the UV initiator.

Furthermore, after the migration to the surface of the coating composition or the polymer film, the reactive groups of the organosilane react with the reactive groups of the polymer and, if present, with the reactive groups of the pigments and / or fillers. This can prevent the organosilane from being washed out from the surface of the coating.

In addition, it was surprisingly found that the dirt-repellent effect of the organosilanes according to the invention is enhanced if they are used in coating compositions (also clear coats) which contain polymer dispersions which contain ethylenically unsaturated ω-hydroxyalkyl acrylates or ω-hydroxyalkyl methacrylates (such as 2-hydroxyethyl methacrylate) and at the same time Epoxyalkylsilanes (e.g. ß- (3,4-

Epoxycyclo-hexyl) ethyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane) contain. In a further preferred embodiment, the at least one polymeric binder of the coating composition according to the invention contains at least one ω-hydroxyalkyl (meth) acrylate as a monomeric building block (comonomer) and at least one epoxyalkylsilane of the formula BSiR ₃ , where the radical B is an organic radical with at least one

Oxirane functionality and the radicals R are alkyl or alkoxy groups of the formula -C _n H2n + ι or -OCnH _2n + ι, where n = 1 to 10.

2-Hydroxyethyl methacrylate is particularly preferably used as ώ-hydroxyalkyl (meth) acrylate and ß- (3,4-epoxycyclohexyl) ethyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane is particularly preferably used as epoxyalkylsilane.

If the organosilanes are used in coating compositions, they can either be used directly in the polymeric binder (in solution or

Dispersion) are added, or added during the production of the coating or the color.

If the additives are used directly to impregnate surfaces, they are preferably applied in solution or dispersion.

The present invention is described in more detail below on the basis of exemplary embodiments, but without being restricted thereby.

A) Description of the test methods:

The hydra- and oleophobicity and dirt-repellent effect of the impregnated surfaces were determined as follows:

Determination of water absorption:

15 g of coating composition are mixed with 9 g of demineralized water and on the underside of a plastic cup with a rim (approx. 11 cm Diameter) poured out. It is dried for 7 days at room temperature, the coating film being peeled off and turned once a day. Then 3 x 3 cm specimens are cut out of the film and detached from the substrate. The films are weighed (double determination) and then stored in water in a petri dish for 24 hours. Then the water is dabbed off with a cellulose cloth and the film is weighed out again. The weight increase in percent on the sample weight corresponds to the first water absorption. The test specimens are then dried for 2 days and the film is then weighed, washed for 24 hours, blotted with a cellulose cloth and weighed again. The second water absorption in percent is determined analogously to the first.

Determination of whitening (water susceptibility):

The dispersion is squeegee on a glass plate (5 x 8 cm) with a 200 μm box doctor blade and dried for one hour at 4Q ° C, then overnight at

Room temperature dried further. The sample is then placed in a Petri dish filled with deionized water and after about 15 minutes the whitening of the polymer film is rated on a relative scale from 1 to 5 (1 = very good, 5 = poor).

Determination of the dry soiling tendency:

The coating is applied to a glass plate with a 200 μm box doctor blade and in the climatic room at 23 ° C and 50% rel. Humidity stored for 24 hours. Then the brightness value L * of the CIELAB color system is measured against an external white standard (L * = 94.33) using an Erichsen colorimeter model no. 526 (measuring geometry 45 °). The sample plate is then rubbed in with a dry brush with fly ash or a mixture of 99.5 parts by weight of fly ash and 0.5 part by weight of carbon black and then brushed off vigorously with the brush. The measurement of the brightness value L * is repeated with the soiled plate. The difference from the original L * value is referred to below as the ΔL * value. Determination of the wet soiling tendency:

Samples are prepared in the same way as for dry soiling, but a fiber cement board, Eterplan 300 x 150 x 4 mm, is used as the substrate. The wet layer thickness of the film is 300 μm. After the L * value has been measured (Erichsen Colorimeter No. 526, see above), the dried sample is fixed with the coating facing upwards over a collecting tray on a base at a 60 ° inclination to the horizontal.

500 ml of an aqueous dispersion of standard dirt is then circulated over the sample using a peristaltic pump. The delivery rate is approx. 500 ml / min. The dirt dispersion running off is collected in the bowl and passed over the sample again. The dispersion is stirred with a magnetic stirrer. After 30 minutes the cycle is interrupted and the sample is dried for 24 hours at room temperature. The brightness value L * is now determined using the Erichsen Colorimeter No. 526. Then the sample is subjected to soiling and drying cycles again. Each time the L * value is determined after the drying cycle. The ΔL * value results from the difference from the original L * value before soiling. A fresh dirt solution is used for each cycle. The dirt solution is produced as follows: 17 g of carbon black FW 200, 70 g of Japanese standard dust No. 8 and 13 g of Special Pitch No.5 (from Worlee) are weighed into a 1000 ml powder bottle and 400 cm ^{3 of} glass beads are added. It is mixed on the trestle for 24 hours and the glass beads are sieved. The powder is homogenized with a mortar and pestle. 1 g of standard dirt powder is placed in a glass vessel with 1 g of butyl glycol and 998 g of water are added. The dispersion is stirred with a magnetic stirrer.

B) Description of the examples:

Example 1 Preparation of the Fluoroalkyl Modified Organosilanes The course of the reaction is monitored analytically via the amine number and via ¹ H-NMR using the intensities of the protons of the acrylate double bond.

a) Product A 50 g Silquest ^® A-Link 15 (N-ethyl-3-trimethoxysilyl-2-methyl propane amine, Fa. Crompton) and 125 g of Fluowet ^® AC 812 (CH ₂ = CHCOOCH2CH ₂ (CF ₂ CF ₂₎ n _F> n = 3 to 6, from Clariant) are reacted in a 250 ml flask under an atmosphere at 75 ° C. with stirring for 6 hours. After cooling to room temperature, 175 g of the product are obtained in the form of an orange-brown mass with solid and liquid components.

b) Product B

50 g Silquest ^® A-Link 15 and 117 g Fluowet ^® AC 800

(CH ₂ = CHCOOCH ₂ CH ₂ (CF ₂ CF ₂₎ ₄ F, Fa. Clariant) are reacted in a 250 ml flask under N ₂ atmosphere at ^'75 ° C with stirring for 6 hours. After cooling to room temperature, 167 g of the product are obtained in the form of a partially crystalline, partly still flowable, orange-brown mass.

c) Product C 50 g Silquest ^® A-Link 15 and 125 g Fluowet ^® AC 812 are reacted in a 500 ml flask under ^ atmosphere in 150 g of anhydrous butyl acetate at 75 ° C with stirring for 8 hours. After cooling to room temperature, 325 g of the product are obtained in the form of a clear, orange-colored solution.

d) Product D

30 g Silquest ^® A 1100 (3-triethoxysilyl-1-propanamine, Fa. Crompton) and 153 g of Fluowet ^® MA 812 are reacted for 10 hours in a 250 ml flask under N ₂ atmosphere at 75 ° C with stirring. After cooling to room temperature, 183 g of the product are obtained in the form of a partially crystalline, partly still flowable, orange-brown mass. e) Product E

40 g Silquest ^® A 1100 and 152 g Fluowet ^® AC 600

(CH ₂ = CHCOOCH ₂ CH ₂ (CF ₂ CF ₂ ) ₃ F, from Clariant) are reacted in a 500 ml flask under an N ₂ atmosphere in 150 g of anhydrous butyl acetate at 75 ° C. with stirring for 8 hours. After cooling to room temperature, 342 g of the product are obtained in the form of a clear, yellow-orange colored solution.

f) Product F

50 g Silquest ^® A 1100 uncM42 ^"g Fluowet ^{® ~} AC ^~ 600 are in a 500 ml flask under N ₂ atmosphere in 150 g of anhydrous butyl acetate at 75 ° C

Stir reacted for 8 hours. After cooling to room temperature, 342 g of the product are obtained in the form of a clear, yellow-orange colored solution.

Table 1

* molar ratio of aminosilane to fluoroacrylate

Example 2

Manufacture of elastic facade coatings

In 100 g of water are successively added with stirring 5 g of a 10% solution of Calgon ^® N and 1, 4 g of Coatex P ^® 90 and 2 g Foammaster 111 ^® FA added. Then 80 g of titanium dioxide (Kronos ^® L 2310) and 380 g

Calcium carbonate (Durcal ^® 2) was added in succession and stirred with a dissolver at 5000 rpm for 15 minutes. Then 382.3 g of a dispersion (solids content approx. 60%) at 500 rpm and 1 g of 20% ammonia water and stirred for 5 minutes. Finally, 2 g of Mergal ^® K9, 2 g of butyl diglycol, 10 g of propylene glycol, 5 g of White Spirit ^® 17/18 and finally a solution of 7.5 g of Coatex ^® BR 100 and 23.2 g of water are added. The mixture is then stirred for a further 5 minutes.

Before use, the paint is stored at room temperature for at least one day.

The following additive is added to the dispersion before it is added to the color paste:

Table 2.

Example 3

Determination of the tendency of the facade coatings to become dry soiled

The fly ash-soot mixture described above as part of the measurement methods was used for soiling. Table 3

As can be seen in Table 3, even very small additional amounts show a significant improvement in the tendency to dry soiling.

Example 4

Determination of the water absorption of the facade coatings

Table 4

As Table 4 shows, the coatings with the organosilanes according to the invention have a reduced water absorption compared to those with a non-reactive fluorine emulsifier as an additive.

Example 5 Determination of the tendency for wet soiling of the facade coatings Table 5

As Table 5 shows, the organosilanes according to the invention lead to an improved early tendency towards wet soiling in the coatings compared to additives with a surfactant character but without reactive functionality.

Example 6

To a dispersion of Mowilith LDM 6636 ^® (Fa. Clariant) may be added various additives for reducing the soiling tendency and the mixture homogenized for 10 minutes with a paddle. Then the respective mixture is drawn onto a glass plate using a 300 μm box doctor blade and dried for 24 hours at room temperature.

Table 6

As Table 6 shows, the organosilanes according to the invention cause an increase and not, like the additives of the prior art, a reduction in the water resistance.

Example 7

Production of an exterior paint

In 130 g of water 2 g of Tylose ^® MH 4000 KG are successively 4 (Fa. Clariant), 3 g Mowiplus ^® XW 330 (Fa. Clariant), 11 g Calgon ^® N (10 wt .-%) and 2 g of 25% dissolved ammonia water. After addition of 2 Mergal ^® K10N g (Fa. Troy) 4 g of Agitan ^® 232 (Fa. Münzing), then 226 g titanium dioxide Kronos ^® 2065 (Fa. Kronos Titan), 168 g Omyacarb ^® 5 GU, 38 g Micro Tale AT1 and 20 g of china clay were added and sheared with the dissolver disc at 5000 rpm for 15 minutes. Then, at 500 rpm in 375 g of Mowilith LDM 6636 ^® (Fa. Clariant) was added. If necessary, a dirt-repellent additive is added to the dispersion, which is worked into the dispersion beforehand using a paddle stirrer. Finally, 11 g of white spirit and 8 g of butyl diglycol acetate are added and stirring is continued for about 10 minutes.

Table 7

The paint is stored for at least one day before use.

Example 8 Measurement of the tendency of the exterior paint to become dry and dirty (fly ash with added soot) Table 8

Example 9

Determination of the tendency to dry soiling (fly ash with added soot)

Styrene-butyl acrylate polymer dispersion in a clear bag

A styrene-butyl acrylate polymer dispersion (solids content: 50%, T _g : 20 ° C.) prepared by emulsion polymerization in water at 80 ° C. and polymerized in 3.8% by weight of 2-hydroxyethyl methacrylate (HEMA), based on the mpomers contains, a) with no additive, b) with 0.5% by weight, based on the solids content of the dispersion, γ-glycidyloxypropyltrimethoxysilane, and c) with 0.5% by weight, based on the solids content of the dispersion, Y-glycidyloxypropyltrimethoxysilane and 1% by weight, based on the solids content of the dispersion, of organosilane from Example 1b as additives.

The resulting dispersion mixtures are applied to glass plates with a box doctor (300 μm wet film thickness) and dried for 24 hours at room temperature. Then the dry soiling tendency (fly ash-soot mixture) is determined. The results are shown in Table 9. Example 10

Determination of the tendency to dry soiling (fly ash with added soot)

Styrene-butyl acrylate polymer dispersion in a clear coat

A styrene-butyl acrylate polymer dispersion of the same composition as that of Example 9, but which does not contain 2-hydroxyethyl methacrylate, is a) with no additive, b) with 0.5% by weight, based on the solids content of the dispersion, - γ -Glycidyloxypropyrtrimethoxysilane, and c) with 0.5 wt .-%, based on the solids content of the dispersion, γ-glycidyloxypropyltrimethoxysilane and 1 wt .-%, based on the solids content of the dispersion, organosilane of Example 1 b.

The resulting dispersions are applied to glass plates using a box doctor (300 μm wet film thickness) and dried for 24 hours at room temperature. Then the dry soiling tendency (fly ash-soot mixture) is determined. The results are shown in Table 9.

Table 9: Dry soiling tendencies of styrene butyl acrylate

Polymer dispersions in the clearcoat of Examples 9 and 10 (fly ash with 0.5% added carbon black)

As Table 9 shows, the combination of ω-hydroxyalkyl (meth) acrylates, γ-glycidyloxypropyltrimethoxysilane and the fluoroalkyl-modified organosilanes according to the invention increases the dirt-repellent effect.

Claims

claims

1. Organosilanes of the general formula (I)

where R is a fluorinated or partially fluorinated alkyl radical of the formula C _n Z ₂ n ₊ ι (CH ₂ ) m-, with n> 1, m ≥ 1 and Z either a hydrogen atom or a fluorine atom, with the

I

Provided that at least one Z is a fluorine atom, 10 Y is a hydrogen atom or alkyl radical with 1 to 10 C atoms,

X is either a hydrogen atom, a linear or branched alkyl radical with 1 to

benzyl

R ^{1 is} a linear or branched alkylene radical having 1 to 20 C atoms and 15 R ² , R ³ and R ^{4 are} linear or branched alkyl radicals having 1 to 10 C atoms or linear or branched alkoxy radicals having 1 to 10 C atoms, which have the

Represent oxygen atom with the silicon atom represent.

20 2. Organosilanes according to claim 1, characterized in that R is a fluorinated alkyl radical of the formula C _n F _2n + ι (CH2) m-.

3. Organosilanes according to claim 1 or 2, characterized in that n = 1 to 30 and m = 1 to 4.

25

4. Organosilanes according to at least one of the preceding claims, characterized in that

X is a methyl, an ethyl, a propyl, a phenyl or a benzyl radical,

Y is a hydrogen atom or methyl radical R ^{1 is} a - (CH ₂ ) 3-, a -CH ₂ CH (CH ₃ ) CH ₂ - or a -C ₂ H ₄ radical, and R ² , R ³ , R ^{4 is} a CH ₃ O-, a C ₂ H _{5 is} 0 or a CH (CH ₃ ) ₂ O radical.

5. Organosilanes according to at least one of the preceding claims, characterized in that n = 6 to 14 and m = 2.

6. organosilanes according to claim 4 or 5, characterized in that X is an ethyl radical,

R ^{1 is} a -CH ₂ CH (CH ₃ ) CH ₂ radical and R ² , R ³ , R ^{4 is} a CH ₃ O radical.

7. organosilanes according to claim 4 or 5, characterized in that X is a methyl radical,

R ^{1 is} a - (CH) ₃ radical and R ² , R ³ , R ^{4 is} a CH ₃ O radical.

8. A process for the preparation of organosilanes of the general formula (I) according to at least one of the preceding claims, characterized in that a (meth) acrylic acid ester of the general formula (II) is reacted with an ω-aminoalkylsilane of the general formula (III),

where R is a fluorinated or partially fluorinated alkyl radical of the formula C _n Z2n + ι (CH ₂ ) m-, m with n> 1, m> 1 and Z either a hydrogen atom or a fluorine atom, with the proviso that at least one Z is a fluorine atom , Y is a hydrogen atom or alkyl radical with 1 to 10 carbon atoms, X is either a hydrogen atom, a linear or branched alkyl radical having 1 to 10 carbon atoms, a radical of the formula ROC (O) (CHY) (CH ₂ ) -, a phenyl or a benzyl radical,

R ^{1 is} a linear or branched alkylene radical having 1 to 20 C atoms and R ² , R ³ and R ^{4 are} linear or branched alkyl radicals having 1 to 10 C atoms or linear or branched alkoxy radicals having 1 to 10 C atoms, which are via the Represent oxygen atom with the silicon atom represent.

9. Use of organosilanes according to at least one of claims 1 to 7 for reducing the tendency towards soiling of surfaces.

10. Use of organosilanes according to at least one of claims 1 to 7 as anti-blocking agents for the treatment of surfaces.

11. Use of organosilanes according to at least one of claims 1 to 7 for the hydrophobization and oleophobicization of surfaces.

12. A method for coating surfaces, characterized in that organosilanes according to at least one of claims 1 to 7 in

Spraying substance, solution or dispersion on the surfaces to be treated, immersing the surface in the solution or dispersion of the additives, or applying with a brush or roller, or adding a substance, solution or dispersion to a coating composition to be applied and adding the coating composition to the surface applying.

13. Use of organosilanes according to at least one of claims 1 to 7 in coating compositions for reducing the tendency towards soiling of surfaces.

14. Use of organosilanes according to at least one of claims 1 to 7 as anti-blocking agents in coating compositions for treating surfaces.

15. Use of organosilanes according to at least one of claims 1 to 7 in coating compositions for the hydrophobization and oleophobicization of surfaces.

16. Coating composition comprising: a) at least one polymeric binder, b) at least one organosilane according to at least one of claims 1 to 7, and c) optionally pigments, fillers, dispersants, thickeners, protective colloids, wetting agents, preservatives, algicides, rust-proofing pigments, UV Filter substances, UV initiators and / or other auxiliary substances.

17. Coating composition according to claim 16, characterized in that it contains at least one UV initiator.

18. Coating composition according to claim 16 or 17, characterized in that the at least one polymeric binder contains at least one ω-hydroxyalkyl (meth) acrylate as a monomeric building block (comonomer) and at least one epoxyalkylsilane of the formula BSiR ₃ , the remainder being B is an organic radical with at least one oxirane functionality and the radicals R are alkyl or alkoxy groups of the formula -CnH _2n + ι or -OC _n H ₂ n + ι, where n = 1 to 10.

19. Coating composition according to claim 18, characterized in that 2-hydroxyethyl methacrylate is used as the ω-hydroxyalkyl (meth) acrylate.

20. Coating composition according to claim 18 or 19, characterized in that β- (3,4-epoxycyclohexyl) ethyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane is used as the epoxyalkylsilane.