HK1120538A - Coating materials containing silane-modified nanoparticles - Google Patents
Coating materials containing silane-modified nanoparticles Download PDFInfo
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- HK1120538A HK1120538A HK08112165.6A HK08112165A HK1120538A HK 1120538 A HK1120538 A HK 1120538A HK 08112165 A HK08112165 A HK 08112165A HK 1120538 A HK1120538 A HK 1120538A
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Description
Background
Coatings comprising nanoparticles which are produced by hydrolytic (co) condensation of Tetraethoxysilane (TEOS) with other metal alkoxides without organic and/or inorganic binders by means of the sol-gel technique are known. It is known from DE 19924644 that sol-gel synthesis can also be carried out in a medium. Preferably, radiation-curable formulations are used. However, all materials made by means of the sol-gel process are characterized by a low solids content of inorganic and organic substances, an increased amount of condensation products (usually alcohols), the presence of water, and a limited storage stability.
One advancement is the high temperature resistant reactive metal oxide particles made by the hydrolytic condensation of metal alkoxides on the surface of nanoscale inorganic particles in the presence of a reactive binder. The temperature resistance of the fully reacted formulation is achieved by heterogeneous copolymerization of the reactive groups of the medium with the same kind of reactive groups of the binder. The disadvantage here is the incompleteness of heterogeneous copolymerizations, in which not all reactive groups on the particle surface participate in the copolymerization. Steric hindrance is the main cause. However, it is well known that incompletely reacted groups lead to unwanted secondary reactions which may cause discoloration, embrittlement or premature degradation. This is particularly true for high temperature applications. Even the process described in DE 19846660 results in a non-storage-stable system due to the acidic medium in the presence of condensation products, usually alcohols.
Furthermore, nanoscale, surface-modified particles (Degussa) are knownR7200) formed by condensation of metal oxides with silanes in the absence of binders and thus in the absence of strong shearing forces such as those generated in viscous media at stirring speeds ≧ 10 m/s. For this reason, these silica aerogels (aerosils) have particles which are larger than the starting materials used, their opacity being significantly higher and their activity being lower than the effect of the particles described in WO 00/22052 and of the varnishes prepared therefrom.
Disclosure of Invention
The object of the present invention is to eliminate the disadvantages of the prior art and to provide storage-stable and property-stable coating compositions comprising specifically prepared nanoscale, inorganic particles.
The present invention provides coating compositions comprising silane-modified nanoparticles and an organic binder and, if appropriate, additives, characterized in that the coating compositions comprise those silane-modified nanoparticles which are obtained by deagglomerating nanoparticle-containing agglomerates in the presence of an organic solvent and simultaneously or subsequently treating with a silane.
Preferred nanoparticles used according to the invention are particles having an average particle size of from 1nm to 200nm, preferably from 1 to 100nm, and consisting of oxides of elements of main group 3, in particular of aluminum.
These nanoparticles are prepared by deagglomerating larger agglomerates comprising or consisting of these nanoparticles in the presence of an organic solvent and simultaneously or subsequently treating with a silane. Such agglomerates are known per se and can be prepared, for example, by the following processes:
via chemical synthesis, which is usually a precipitation reaction with subsequent calcination (precipitation of hydroxides, hydrolysis of organometallic compounds). In this case, in order to lower the transition temperature to α -alumina, crystallization nuclei are often added. The sol thus obtained is dried and converted into a gel in the process. Then further calcination is carried out at a temperature of 350 ℃ to 650 ℃. To be converted into alpha-Al2O3Then, annealing must be performed at a temperature of about 1000 ℃. This process is described in detail in DE 19922492.
Another approach to obtaining nanomaterials is the aerosol method. In this case, the desired molecules are obtained by chemical reaction of the precursor gases or by rapid cooling via supersaturated gases. Particles are formed by collisions of molecular clusters or by continued evaporation and condensation in equilibrium. The newly formed particles grow by further collisions with product molecules (condensation) and/or further collisions with particles (agglomeration). If the agglomeration rate is greater than the newly formed rate and/or the growth rate, agglomerates of spherical primary particles are formed.
Flame reactors are a production variant based on this principle. In this case, the nanoparticles are formed by decomposition of the precursor molecules in a flame at 1500 ℃ to 2500 ℃. AsExamples may mention TiCl4；SiCl4And Si2O(CH3)6In methane/O2Oxidation in the flame, which produces TiO2And SiO2Particles. Using AlCl3Until now, only the corresponding aluminas had been formed. Flame reactors are currently used on an industrial scale for the synthesis of submicron particles, such as carbon black, pigmentary TiO2Silicon dioxide (a)) And alumina.
Small particles can also be formed even from liquid droplets by means of centrifugal force, compressed air, sound waves, ultrasound and other methods. The droplets are then converted to a powder by direct pyrolysis or by in situ reaction with other gases. Spray drying and freeze drying may be mentioned as known methods. In the case of spray pyrolysis, the precursor droplets are conveyed through a high-temperature field (flame, furnace), which leads to rapid evaporation of the volatile components or initiates decomposition reactions to produce the desired product. The desired particles are collected in a filter. Mention may be made here, as an example, of the preparation of BaTiO from an aqueous solution of barium acetate and titanium lactate3。
It is likewise possible to attempt to break up the corundum by grinding and in this case to produce crystallites in the nanometer range. The best grinding results can be obtained in wet grinding by means of a stirred ball mill. In this case, grinding beads made of a material having a hardness greater than corundum must be used.
Another way to prepare corundum at low temperatures is the conversion of aluminum chlorohydrate. For this purpose, it is likewise mixed with seed crystals, preferably seed crystals made of ultrafine corundum or hematite. To avoid crystal growth, the samples must be calcined at temperatures from about 700 ℃ up to 900 ℃. The duration of the calcination in this case is described as at least 4 hours. However, it has recently been found that under this method, calcination over a period of 0.5 to 10 minutes is entirely sufficient to produce nanocrystalline corundum. Preferred such methods in the context of the present invention are described in detail in Ber. (report) DKG 74(1997) No.11/12, pages 719-722.
Specifically, the preferred nano corundum preparation is carried out as follows:
starting from a compound of formula Al2(OH)xClyWherein x is a number from 2.5 to 5.5 and y is a number from 3.5 to 0.5, and the sum of x and y is always 6. The aluminum chlorohydrate is mixed as an aqueous solution with the crystallization nuclei, followed by drying and subsequent heat treatment (calcination).
It is preferred in this case to start from a 50% strength aqueous solution such as those which are commercially available. Mixing the solution with promoting Al2O3The crystal nuclei formed by the alpha-modification of (a) are mixed. More particularly, the crystal nuclei cause a reduction in the α -modification formation temperature during the subsequent heat treatment. Suitable nuclei include ultra-finely divided corundum, diaspore or hematite. Preference is given to using an ultrafine-dispersed alpha-Al having a mean particle size of less than 0.1. mu.m2O3And (4) a crystal nucleus. In general, 2 to 3 wt.%, based on the formed alumina, of the crystal nuclei is sufficient.
The starting solution may additionally comprise an oxide former. Particularly suitable in this connection are chlorides, oxychlorides and/or hydrochlorides of elements of main groups II to V and of subgroups of elements, more particularly chlorides, oxychlorides and/or hydrochlorides of the elements Ca, Mg, Y, Ti, Zr, Cr, Fe, Co and Si.
The suspension of aluminum chlorohydrate, nuclei and, if appropriate, oxide formers is then evaporated to dryness and subjected to a heat treatment (calcination). The calcination is carried out in an apparatus suitable for this purpose, for example in a horizontal pusher (Durchschub) furnace, a box furnace, a tube furnace, a rotary kiln or a microwave furnace or in a fluidized bed reactor. In a variant of the process according to the invention, it is also possible to inject the aqueous suspension of aluminum chlorohydrate and of the nuclei directly into the calcining apparatus without prior removal of water.
The calcination temperature should not exceed 1100 ℃. The lower temperature limit depends on the desired yield of nanocrystalline corundum, on the desired residual chlorine content and on the content of crystal nuclei. The formation of corundum already starts at about 500 ℃, however, in order to keep the chlorine content low and the yield of nanocrystalline corundum high, it is preferred to operate at temperatures of 700-.
It has been shown that generally 0.5 to 30 minutes, preferably 0.5 to 10 minutes, more particularly 0.5 to 5 minutes are sufficient for the calcination. After this short time, a sufficient yield of nanocrystalline corundum can already be achieved under the conditions of the preferred temperatures mentioned above. However, calcination may also be carried out at 700 ℃ for 4 hours or at 500 ℃ for 8 hours, according to the information in Ber.DKG 74(1997) No.11/12, page 722. During calcination, agglomerates of nanocrystalline corundum in the form of almost spherical nanoparticles are produced.
From these agglomerates, which comprise the desired nanoparticles in microcrystalline form or consist entirely of them, the nanoparticles have to be released. This is preferably done by grinding or by treatment with ultrasound. There are two possibilities for the modification according to the invention of these nanoparticles with silanes. According to a first variant, the deagglomeration can be carried out in the presence of silane, for example by adding silane to the mill during milling. A second possibility is to first destroy the nano-corundum agglomerates and then treat the nanoparticles, preferably in the form of a suspension in an organic solvent, with a silane.
Suitable silanes in this connection are preferably of the following type:
a)R[-Si(R’R”)-O-]nsi (R ') -R ' or ring [ -Si (R ') -O-]rSi(R’R”)-O-
Wherein
R, R ', R ' and R ' equal to or different from each other are each an alkyl group having 1 to 18 carbon atoms, or a phenyl group, or an alkylphenyl or phenylalkyl group having 6 to 18 carbon atoms, or of the formula- (C)mH2m-O)p-CqH2q+1Or of the formula-CsH2sA group of Y,Or of the formula-XZt-1The group of (a) or (b),
n is an integer defined as 1. ltoreq. n.ltoreq.1000, preferably 1. ltoreq. n.ltoreq.100,
m is an integer 0. ltoreq. m.ltoreq.12 and
p is an integer 0. ltoreq. p.ltoreq.60 and
q is an integer of 0. ltoreq. q.ltoreq.40 and
r is an integer of 2. ltoreq. r.ltoreq.10 and
s is an integer 0. ltoreq. s.ltoreq.18 and
y is a reactive group, examples being alpha, beta-ethylenically unsaturated groups such as (meth) acryloyl, vinyl or allyl, amino, amido, ureido, hydroxyl, epoxy, isocyanato, mercapto, sulfonyl, phosphonyl, trialkoxysilyl, alkyldialkoxysilyl, dialkylmonoalkoxysilyl, anhydride and/or carboxyl, imido, imino, sulfite, sulfate, sulfonate, phosphino, phosphite, phosphate, phosphonate, and
x is a t-functional oligomer, wherein
t is an integer of 2. ltoreq. t.ltoreq.8, and
z is again a radical of formula
R[-Si(R’R”)-O-]nSi (R ') -R ' or ring [ -Si (R ') -O-]rSi(R’R”)-O-。
The t-functional oligomer X is preferably selected from the following:
oligoethers, oligoesters, oligoamides, oligourethanes, oligopolyureas, oligoolefins, oligovinyl halides, oligovinylidene halides, oligoimines, oligovinyl alcohols, esters, acetals or ethers of oligovinyl alcohols, cooligomers of maleic anhydride, (meth) acrylic acid oligomers, (meth) acrylic acid esters oligomers, (meth) acrylamide oligomers, (meth) acrylimide oligomers, and (meth) acrylonitrile oligomers, with oligoethers, oligoesters, and oligourethanes being particularly preferred.
An example of an oligoether group is- (C)aH2a-O)b-CaH2a-or O- (C)aH2a-O)b-CaH2aCompounds of the type-O, where 2. ltoreq. a.ltoreq.12 and 1. ltoreq. b.ltoreq.60, for example diethylene glycol, triethylene glycol or tetraethylene glycol radicals, dipropylene glycol, tripropylene glycol, tetrapropylene glycol radicals, dibutylene glycol, tributylene glycol or tetrabutylene glycol radicals. An example of an oligomeric ester group is-CbH2b-(O(CO)CaH2a-(CO)O-CbH2b-)c-or-O-CbH2b-(O(CO)CaH2a-(CO)O-CbH2b-)cCompounds of the O-type, in which a and b are different or identical, 3. ltoreq. a.ltoreq.12, 3. ltoreq. b.ltoreq.12 and 1. ltoreq. c.ltoreq.30, for example oligoesters of hexanediol and adipic acid.
b)(RO)3Si(CH2)mOrganosilanes of the type-R
R ═ alkyl, such as methyl, ethyl, propyl,
m＝0.1-20，
r' is methyl, phenyl,
-C4F9、OCF2-CHF-CF3、-C6F13、-O-CF2-CHF2
-NH2、-N3、-SCN、-CH＝CH2、-NH-CH2-CH2-NH2，
-N-(CH2-CH2-NH2)2
-OOC(CH3)C＝CH2
-OCH2-CH(O)CH2
-NH-CO-N-CO-(CH2)5
-NH-COO-CH3、-NH-COO-CH2-CH3、-NH-(CH2)3Si(OR)3
-Sx-(CH2)3)Si(OR)3
-SH
-NR 'R "R'" (R '═ alkyl, phenyl; R "═ alkyl, phenyl; R'" H, alkyl, phenyl, benzyl
C2H4NR "" "R" ", wherein R" "═ a, alkyl, and R" "' ═ H, alkyl).
Examples of silanes of the above-defined type are, for example, hexamethyldisiloxane, octamethyltrisiloxane, SinOn-1(CH3)2n+2A series of other homologous and isomeric compounds, wherein
n is an integer of 2. ltoreq. n.ltoreq.1000, e.g. polydimethylsiloxaneLiquid (20 cSt).
Hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, (Si-O)r(CH3)2rA series of other homologous and isomeric compounds, wherein
r is an integer of 3. ltoreq. r.ltoreq.12,
dihydroxytetramethyldisiloxane, dihydroxyhexamethyltrisiloxane, dihydroxyoctamethyltetrasiloxane, HO- [ (Si-O)n(CH3)2n]-Si(CH3)2-OH or HO- [ (Si-O)n(CH3)2n]-[(Si-O)m(C6H5)2m]-Si(CH3)2Other homologous and isomeric compounds of the-OH series, in which
m is an integer of 2-1000,
preference is given to alpha, omega-dihydroxypolysiloxanes, such as polydimethylsiloxane (OH end groups, 90-150cST) or polydimethylsiloxane-co-diphenylsiloxane (dihydroxy end groups, 60 cST).
Dihydrohexamethyltrisiloxane, dihydrooctamethyltetrasiloxane, H- [ (Si-O)n(CH3)2n]-Si(CH3)2Other homologous and isomeric compounds of the H series, in which
n is an integer from 2. ltoreq. n.ltoreq.1000, preferably an alpha, omega-dihydropolysiloxane, for example polydimethylsiloxane (hydride end groups, M)n＝580)。
Bis (hydroxypropyl) hexamethyltrisiloxane, bis (hydroxypropyl) octamethyltetrasiloxane, HO- (CH)2)u[(Si-O)n(CH3)2n]-Si(CH3)2(CH2)uOther homologous and isomeric compounds of the-OH series, preferably alpha, omega-dimethanol-based polysiloxanes, where 3. ltoreq. u.ltoreq.18, 3. ltoreq. n.ltoreq.1000, or their polyether-modified derivatised (Nachfolge) compounds HO- (EO/PO) based on Ethylene Oxide (EO) and Propylene Oxide (PO) as homopolymers or copolymersv-(CH2)u[(Si-O)t(CH3)2t]-Si(CH3)2(CH2)u-(EO/PO)v-OH, preferably an alpha, omega-di (carbinol polyether) polysiloxane, wherein 3. ltoreq. n.ltoreq.1000, 3. ltoreq. u.ltoreq.18, 1. ltoreq. v.ltoreq.50.
Instead of the α, ω -OH groups, it is likewise possible to use the corresponding difunctional compounds with epoxy, isocyanato, vinyl, allyl and di (meth) acryloyl groups, for example polydimethylsiloxane having vinyl end groups (850-1150cST) or TEGORAD 2500 from Tego Chemie Service.
Also suitable are esterification products of ethoxylated/propoxylated trisiloxanes and higher siloxanes using acrylic copolymers and/or maleic copolymers as modifying compounds, for example BYK Silclean 3700 from Byk ChemieOr from Tego Chemie service GmbHProtect 5001。
Instead of the α, ω -OH groups, it is likewise possible to use the corresponding difunctional compounds with — NHR "", where R "═ H or alkyl groups, examples being the well-known aminosilicones from Wacker, Dow Corning, Bayer, Rhodia et al, which carry (cyclo) alkylamino or (cyclo) alkylimino groups randomly distributed over the polysiloxane chain in their polymer chain.
(RO)3Si(CnH2n+1) And (RO)3Si(CnH2n+1) Organosilane of type (I) in which
R is an alkyl group, such as methyl, ethyl, n-propyl, isopropyl, butyl,
n is 1 to 20.
R’x(RO)ySi(CnH2n+1) And (RO)3Si(CnH2n+1) Organosilane of type (I) in which
R is an alkyl group such as methyl, ethyl, n-propyl, isopropyl, butyl,
r' is an alkyl group such as methyl, ethyl, n-propyl, isopropyl, butyl,
r' is a cycloalkyl group,
n is an integer of 1 to 20,
x + y is 3, and x + y is,
x is 1 or 2, and the compound is,
y is 1 or 2.
(RO)3Si(CH2)mOrganosilanes of the type-R', in which
R is an alkyl group such as methyl, ethyl, propyl,
m is a number of 0.1 to 20
R' is methyl, phenyl, -C4F9、OCF2-CHF-CF3、-C6F13、-O-CF2-CHF2、-NH2、-N3、-SCN、-CH＝CH2、-NH-CH2-CH2-NH2，-N-(CH2-CH2-NH2)2、-OOC(CH3)C＝CH2、-OCH2-CH(O)CH2、-NH-CO-N-CO-(CH2)5、-NH-COO-CH3、-NH-COO-CH2-CH3、-NH-(CH2)3Si(OR)3、-Sx-(CH2)3Si(OR)3-SH-NR 'R "R'" (R '═ alkyl, phenyl; R "═ alkyl, phenyl; R'" ═ H, alkyl, phenyl, benzyl, C2H4NR "" "R" ", wherein R" "═ a, alkyl, and R" "' ═ H, alkyl).
Preferred silanes are the compounds listed below:
triethoxysilane, octadecyltrimethoxysilane, 3- (trimethoxysilyl) propyl methacrylate, 3- (trimethoxysilyl) propyl acrylate, 3- (trimethoxysilyl) methyl methacrylate, 3- (trimethoxysilyl) methyl acrylate, 3- (trimethoxysilyl) ethyl methacrylate, 3- (trimethoxysilyl) ethyl acrylate, 3- (trimethoxysilyl) pentyl methacrylate, 3- (trimethoxysilyl) pentyl acrylate, 3- (trimethoxysilyl) hexyl methacrylate, 3- (trimethoxysilyl) hexyl acrylate, 3- (trimethoxysilyl) butyl methacrylate, 3- (trimethoxysilyl) butyl acrylate, octadecyltrimethoxysilane, 3- (trimethoxysilyl) propyl methacrylate, 3- (trimethoxysilyl) propyl acrylate, 3- (trimethoxysilyl) methyl methacrylate, 3- (trimethoxysilyl) butyl methacrylate, and mixtures thereof, 3- (trimethoxysilyl) heptyl methacrylate, 3- (trimethoxysilyl) heptyl acrylate, 3- (trimethoxysilyl) octyl methacrylate, 3- (trimethoxysilyl) octyl acrylate, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutylsilaneTrimethoxysilane, isobutyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, hexadecyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, tridecafluoro-1, 1, 2, 2-tetrahydrooctyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, oligomeric tetraethoxysilane (from Degussa)40) Tetra-n-propoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, triaminofunctional propyltrimethoxysilane (available from Degussa, Inc.)TRIAMINO), N- (N-butyl) -3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane.
These silanes are preferably added in a molar ratio of corundum to silane of from 1: 1 to 10: 1. The amount of organic solvent in the deagglomeration is generally from 80 to 90% by weight, based on the total amount of corundum and solvent. Solvents which can be used are in principle all organic solvents. Preferably, C is suitable1-C4Alcohols, more particularly methanol, ethanol or isopropanol, and also acetone or tetrahydrofuran.
The deagglomeration by grinding and the modification with silanes at the same time are preferably carried out at temperatures of from 20 to 150 ℃ and particularly preferably from 20 to 90 ℃.
If deagglomeration is carried out by grinding, the suspension is subsequently separated from the grinding beads.
After deagglomeration, the suspension may be heated up to 30 hours to complete the reaction. Finally the solvent is removed by distillation and the remaining residue is dried.
It is also possible to suspend the corundum in a corresponding solvent and, after deagglomeration, to react with the silane in a further step.
The coating compositions of the invention, as ceramic coatings, electro-alumina (Eloxal) coatings, but preferably as varnishes, further comprise conventional and known binders, examples of which are those described below:
varnish binders for single-component and multi-component polymer systems, i.e. in the case of multi-component polymer systems, not only the resins but also the curing agents, can be filled with the particles described under a) and b), and can contain the above-mentioned components known from coating technology:
examples of mono-or polyfunctional acrylates are butyl acrylate, ethylhexyl acrylate, norbornyl acrylate, butanediol diacrylate, hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane triethoxy triacrylate, pentaerythritol tetraethoxytriacrylate, pentaerythritol tetraethoxytetraacrylate, polyether acrylates, urethane acrylates, for example from Cray Valley Kunstharze GmbHCN 925, CN 981 from UCB GmbHEB 1290, Laromer8987 from BASF AG, from Cognis6019 or6010 polyester acrylates, for example from Cray Valley Kunstharze GmbHCN 292 from BASF AGLR 8800 from UCB GmbHEB 800 from Cognis5429F and5960 F，
epoxy acrylates, e.g. from BASF AGEA 81 from UCB GmbHEB 604, from Cray Valley Kunstharze GmbHCN104D80，
Dendritic polyester/ether acrylates from Perstorp Speciality ChemicalAG or from Bayer AG,
polyurethane polymers and their precursors, in the form of polyisocyanates, polyols, polyurethane prepolymers, as blocked prepolymers and as fully reacted polyurethanes in the melt or solution. Specifically these are:
polyols in the form of polyethers, e.g. polyethylene glycol 400, available from Dow ChemicalsP400 andCP 3055, polyesters, e.g. fromOf GmbH8107、8109 from Bayer AG670、1300 from Degussa AGT1136 alkyd resins, e.g. from Worlse Chemie GmbHC625，
Polycarbonates, e.g.C200, hydroxy-containing polyacrylates, e.g. from Bayer AGA 365，
Polyisocyanates, e.g. from Bayer AGN 3300、VL、Z 4470、IL orL75 from Degussa AGT1890L from Rhodia Syntech GmbHWT 2102，
Polyurethane prepolymers, e.g. from Bayer AGE4280 from Degussa AGEP-U 423，
PMMA and other polyalkyl (meth) acrylates, e.g. from Degussa AGP550 andLP 50/01，
polyvinyl butyrals and other polyvinyl acrylates, e.g. from Clariant GmbHB 30 HH，
Polyvinyl acetates and copolymers thereof, e.g. from Wacker-Chemie GmbHB 100/20 VLE。
For all polymers, both aliphatic and aromatic variants are explicitly included. The binder may also be selected so that it is the same as the silane used for the functionalization.
The binder preferably has a molecular weight of 100-800 g/mol. The binder content in the total coating composition is preferably from 80 to 99% by weight, more particularly from 90 to 99% by weight.
The coating compositions of the invention may further comprise further additives customary in coating technology, examples being reactive diluents, solvents and cosolvents, waxes, matting agents, lubricants, defoamers, deaerators, levelling agents, thixotropic agents, thickeners, organic and inorganic pigments, fillers, adhesion promoters, corrosion inhibitors, anticorrosion pigments, UV stabilizers, HALS compounds, radical scavengers, antistatic agents, wetting agents and dispersants and/or catalysts, co-catalysts, initiators, radical generators, photoinitiators, photosensitizers and the like which are necessary depending on the curing mode. Suitable further additives also include polyethylene glycols and other water-retaining agents, PE waxes, PTFE waxes, PP waxes, amide waxes, FT paraffins, montan waxes, graft waxes, natural waxes, macrocrystalline and microcrystalline paraffins, polar polyolefin waxes, sorbitan esters, polyamides, polyolefins, PTFE, wetting agents or silicates.
It is intended to illustrate the subject matter of the invention in more detail in terms of the following examples without limiting the possible variations.
Detailed Description
Examples
Example 1:
an aqueous solution of aluminum chlorohydrate of 50% strength was mixed with 2% ultrafine corundum suspension crystallization nuclei. After homogenizing the solution by stirring, drying was carried out in a rotary evaporator. The solid aluminum chlorohydrate was pulverized in a mortar, wherein a coarse powder was produced.
The powder was calcined in a muffle furnace at 1050 ℃. The contact time in the hot zone was 5 minutes at the maximum. This results in a white powder with a particle size distribution corresponding to the feed material.
X-ray structural analysis showed that the material was phase pure alpha-alumina. Images taken of REM photographs (scanning electron microscopy) show crystallites of 10-100 nm. The residual chlorine content is only a few ppm. Nanoparticles were obtained by suspending 150g of the corundum powder in 110g of isopropanol and grinding the suspension in a vertical stirred ball mill for 3 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried at 100 ℃ for 20 hours.
Example 2:
150g of corundum powder with a particle size of 10-50 μm, consisting of crystallites < 100nm, are suspended in 110g of isopropanol. To the suspension, 40g of trimethoxyoctylsilane were added and fed to a vertical stirred ball mill from Netzsch (model PE 075). The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.3 to 0.5 mm. After 3 hours, the suspension was separated from the grinding beads and cooked under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 110 ℃ for a further 20 hours.
Images taken of REM photographs (scanning electron microscopy) show the presence of 10-100nm crystallites.
Example 3:
150g of corundum powder with a particle size of 50-200 μm, consisting of crystallites < 100nm, are suspended in 110g of isopropanol. To the suspension 40g of trimethoxyoctylsilane were added and fed into a horizontal stirred ball mill. The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.5 to 1.0 mm. After 6 hours, the suspension was separated from the grinding beads and cooked under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 110 ℃ for a further 20 hours.
Images taken of REM photographs (scanning electron microscopy) show the presence of 10-100nm crystallites.
Example 4:
50g of corundum powder with a particle size of 10-50 μm, consisting of crystallites < 100nm, are suspended in 180g of isopropanol. To the suspension, 20g of trimethoxyoctadecylsilane were added and fed to a vertical stirred ball mill from Netzsch (model PE 075). The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.3 to 0.5 mm. After 3 hours, the suspension was separated from the grinding beads and cooked under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 110 ℃ for a further 20 hours.
Example 5:
50g of corundum powder with a particle size of 50-200 μm, consisting of crystallites < 100nm, are suspended in 180g of isopropanol. To the suspension was added 20g of trimethoxyoctadecylsilane and fed into a horizontal stirred ball mill. The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.5 to 1.0 mm. After 6 hours, the suspension was separated from the grinding beads and cooked under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 110 ℃ for a further 20 hours.
Example 6:
40g of corundum powder with a particle size of 10-50 μm and consisting of crystallites < 100nm are suspended in 160g of methanol. To the suspension, 10g of 3- (trimethoxysilyl) propyl methacrylate were added and fed to a vertical stirred ball mill from Netzsch (model PE 075). The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.3 to 0.5 mm. After 3 hours, the suspension was separated from the grinding beads and cooked under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 80 ℃ for a further 20 hours.
Example 7:
40g of corundum powder with a particle size of 50-100 μm, consisting of crystallites < 100nm, are suspended in 160g of methanol. To the suspension, 10g of 3- (trimethoxysilyl) propyl methacrylate was added and fed into a horizontal stirred ball mill. The grinding beads used consist of zirconium oxide (stabilized with yttrium) and have a size of 0.5 to 1.0 mm. After 6 hours, the suspension was separated from the milling beads and boiled under reflux for a further 4 hours. The solvent was subsequently removed by distillation and the remaining wet residue was dried in a drying cabinet at 80 ℃ for a further 20 hours.
Application examples
The non-surface-modified nano-corundum from example 1 and the various surface-modified corundum samples from examples 2 to 7 were tested for abrasion resistance, gloss and scratch resistance in various varnish systems. The tests were carried out in a waterborne acrylic varnish system, a two-component polyurethane varnish system and a 100% UV varnish system.
I. Aqueous acrylic varnish system
Degree of gloss
The gloss of the clear paint film on the glass plate was measured at an angle of 60 ℃ with a micro-gloss meter (micro-gloss) from BYK-Gardner.
| Degree of gloss | |
| Without additives | 115 |
| 1% nano corundum | 107 |
| 2% nano corundum | 99 |
| 4% nanometer corundum | 81 |
| 6% nano corundum | 75 |
Hardness of pencil
The hardness of the clear coat film on the glass plates was determined by means of the Wolff-Wilborn pencil hardness according to the following scale.
| Soft |
| 6B |
| 5B |
| 4B |
| 3B |
| 2B |
| B |
| HB |
| F |
| H |
| 2H |
| 3H |
| 4H |
| 5H |
| 6H |
| 7H |
| 8H |
| 9H |
| Hard |
| Hardness of pencil | |
| Without additives | 2B |
| 1% nano corundum | B |
| 2% nano corundum | B |
| 4% nanometer corundum | HB |
| 6% nano corundum | HB |
Taber test-abrasion
The varnish samples were sprayed onto specific glass plates using an air gun. Haze was measured with Haze-Gard Plus after various revolutions using a Taber abrasion tester and the change in Haze was calculated.
| After 10 turns | After 20 turns | After 50 turns | |
| Without additives | 13 | 6 | 8 |
| 1% nano corundum | 13 | 7 | 10 |
| 2% nano corundum | 11 | 5 | 8 |
| 4% nanometer corundum | 2 | 1 | 1 |
| 6% nano corundum | 2 | 0 | 0 |
Two-component polyurethane varnish
The samples from examples 2 to 7 were dispersed into the first component of the 2K-PUR varnish system.
Wear and tear
The varnish samples were sprayed onto specific glass plates using an air gun. After various revolutions, the final mass is determined and the wear is calculated accordingly using a Taber wear tester.
| Final mass [ mg] | After 10 turns | After 20 turns | After 50 turns | After 100 turns |
| 4% corundum/example 6 or 7 | 0.0 | 0.5 | 1.4 | 3.3 |
| Additive-free varnish | 0.1 | 0.4 | 1.2 | 3.7 |
| 3％ NANOBYK-3610 | 0.6 | 0.8 | 1.7 | 3.8 |
| 4% corundum/example 2 or 3 | 0.0 | 0.5 | 1.1 | 3.8 |
| 4% corundum/example 4 or 5 | 0.0 | 0.5 | 1.7 | 4.1 |
| 10% corundum/example 2 or 3 | 0.3 | 0.8 | 2.2 | 4.8 |
Nanobyk is a dispersion of surface-modified nano-aluminum in methoxypropyl acetate as a solvent for improving scratch resistance.
Degree of gloss
The gloss of the clear paint film on the glass plate was measured at an angle of 60 ° using a micro gloss meter from BYK-Gardner. (Wet film thickness 60 μm)
| Gloss/60 ° | |
| Without additives | 145 |
| 4% Nano corundum/example 4 or 5 | 132 |
| 4% Nano corundum/example 6 or 7 | 131 |
| 4% Nano corundum/example 2 or 3 | 126 |
| 10% Nano corundum/example 2 or 3 | 120 |
| 6% Nano corundum/example 2 or 4 | 110 |
| 3％ NANOBYK-3610 | 94 |
Hardness of pencil
The hardness of the clear coat film on the glass plates was determined by means of the Wolff-Wilborn pencil hardness.
| Hardness of | |
| Without additives | F |
| 10% Nano corundum/example 2 or 3 | F |
| 6% Nano corundum/example 2 or 3 | F |
| 4% Nano corundum/example 4 or 5 | F-H |
| 3％ NANOBYK-3610 | H |
| 4% Nano corundum/example 2 or 3 | H |
UV varnish
The samples from examples 1 to 7 were dispersed into the first component of the 2K-PUR varnish system.
Wear and tear
The varnish samples were sprayed onto specific glass plates using an air gun. After various revolutions, the final mass is determined and the wear is calculated accordingly using a Taber wear tester.
| Final mass [ mg] | 50 turn | 100 turns | 200 turn |
| Corundum/example 6 or 7 | 1.1 | 2.4 | 6.7 |
| 2％ Nanobyk-3601 | 1.2 | 2.8 | 7.2 |
| Corundum/example 1 | 0.4 | 2.1 | 8.0 |
| Corundum/example 2 or 3 | 0.8 | 2.6 | 8.2 |
| Corundum/example 4 or 5 | 0.9 | 2.8 | 8.6 |
| Without additives | 1.0 | 3.5 | 11.7 |
Degree of gloss
The gloss of the clear paint film on the glass plate was measured at an angle of 60 ° using a micro gloss meter from BYK-Gardner. (Wet film thickness 60 μm)
| Gloss/60 ° | |
| Nano corundum/example 6 or 7 | 136 |
| Without additives | 135 |
| 2％ NANOBYK-3601 | 132 |
| Nano corundum/example 1 | 122 |
| Nano corundum/example 2 or 3 | 121 |
| Nano corundum/example 4 or 5 | 99 |
Hardness of pencil
The hardness of the clear coat film on the glass plates was determined by means of the Wolff-Wilborn pencil hardness.
Haze of clear coat film
Haze (wet film thickness 60 μm) was determined with Haze-Gard Plus, according to the varnish film layer drawn onto a glass plate.
| Resin/haze | |
| Without additives | 0.4 |
| Nano corundum/example 6 or 7 | 1.1 |
| NANOBYK-3601 | 2.2 |
| Nano corundum/example 4 or 5 | 9.4 |
| Nano corundum/example 2 or 3 | 14.1 |
| Nano corundum/example 1 | 17.0 |
Claims (6)
1. A coating composition comprising silane-modified nanoparticles and an organic binder and optionally additives, said coating composition comprising silane-modified nanoparticles obtained by deagglomeration of nanoparticle-containing agglomerates in the presence of an organic solvent and simultaneous or subsequent treatment with a silane.
2. The coating composition of claim 1, characterized in that the coating composition is a varnish.
3. The coating composition according to claim 1, characterized in that the coating composition comprises silane-modified nanoparticles obtained by deagglomeration of nanoparticle-containing agglomerates via milling or under the action of ultrasound.
4. The coating composition according to claim 1, characterized in that the coating composition comprises silane-modified nanoparticles obtained by deagglomeration of nanoparticle-containing agglomerates by grinding and simultaneous treatment with silane.
5. The coating composition according to claim 1, characterized in that the coating composition comprises silane-modified nanoparticles obtained by deagglomeration of nanoparticle-containing agglomerates via grinding and simultaneous treatment with a lower alcohol.
6. The coating composition according to claim 1, characterized in that the coating composition comprises silane-modified nanoparticles obtained by deagglomeration of nanoparticle-containing agglomerates via grinding and simultaneous treatment with silane in a lower alcohol at a temperature of 20 to 150 ℃.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102005039436.1 | 2005-08-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| HK1120538A true HK1120538A (en) | 2009-04-03 |
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