Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter
Reexamination Certificate
2001-10-05
2004-02-10
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Particulate matter
C523S212000, C523S213000, C523S214000, C523S209000, C524S261000, C524S263000, C428S404000, C428S405000, C428S406000, C428S407000
Reexamination Certificate
active
06689468
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to organosilicon nanocapsules having a nanoscale core A, and a substantially complete organosilicon shell B, processes for preparing, and uses of same. Such compounds are particularly suited for use in scratch-resistant coatings.
2. Discussion of the Background
It is known that the surface properties of sol or gel particles or of metal or semimetal oxides can be modified by treatment with a hydrolyzable organosilane or organosiloxane, which generally involves the attachment of just a single-ply silane layer to the oxide or sol gel particle. Oxides or sol or gel particles treated in this way, examples being inorganic pigments or fillers, may be incorporated into a polymer matrix, films, coating compositions and coatings producible therewith. In general, however, the scratch resistance of such polymer systems is low.
DE 198 46 660 discloses nanoscale, surface-modified oxide or mixed-oxide particles enveloped by organosilicon groups bonded covalently to the oxide particle, the organofunctional groups being described as reactive groups and normally being oriented outward, so that by means of polymerization they are bound into the polymer matrix with the polymer material when the prepolymer is cured. The process of preparing such coating compositions is complicated, since the organosilane and the oxide component are incorporated separately into the prepolymer.
DE 198 46 659 possesses the same priority as DE 198 46 660 and relates to a laminate provided with a scratch-resistant synthetic-resin layer which likewise contains nanoscale, surface-modified oxide particles. DE 198 46 659 teaches specifically the use of acryloyloxyalkylsilanes to produce a shell around nanoscale oxide particles that possess reactive, radiation-crosslinkable groups. The preparation of the coating composition in this case is likewise via a time-consuming reaction of a nanoscale silica with methacryloyloxypropyltrimethoxysilane (DYNASYLAN® MEMO) in an acrylate formulation in the presence of water, an acid, and a wetting agent. Again, the components must be brought together separately and in a specific sequence.
Hydrolyzable silane components having ethylenically unsaturated organic groups are usually high-priced starting materials, however. In addition, DYNASYLAN® MEMO tends to react in the presence of even slight traces of a polymerization initiator or radiation with the undesirable result that the viscosity of a corresponding formulation may rise drastically. To avoid the unwanted polymerization, stabilizers must be added. It is therefore often difficult to master the handling of the starting materials and the preparation of such coating systems.
The coating compositions described above are frequently of high viscosity, and usually contain only a small fraction of oxide particles, which impacts the scratch resistance of the subsequent coating. It is difficult to apply such highly viscous coating compositions to a substrate, especially when the substrate in question is thin and can be destroyed by tearing. The scratch resistance of coatings obtainable in this way is in need of improvement, and with such highly viscous systems, a specific, complex application apparatus is required. In many cases, as well, solvents are added to coating compositions of such high viscosity, but this undesirably leads to an increase in the organic emissions (VOC problem; VOC=volatile organic compounds).
SUMMARY OF THE INVENTION
It is an object of the present invention to provide organosilicon-modified nanoparticles and a process for their production.
Another object is to provide a process for preparing coating compositions for scratch-resistant coatings in as simple and economic a manner as possible.
Another object of the invention is to provide articles with a corresponding scratch-resistant synthetic-resin coating.
Another object of the invention is to provide nanocapsules that are directly available in a composition for scratch resistant coatings.
These and other objects have now been achieved by the present invention, the first embodiment of which provides an organosilicon nanocapsule, which includes:
a nanoscale core A, which includes:
at least one particle including at least one oxide or mixed oxide, KA—O, of at least one metal or semimetal selected from the group including main groups 2 to 6 of the Periodic Table, transition groups 1 to 8 of the Periodic Table, lanthanides, and mixtures thereof; and
an organosilicon shell B, which includes:
at least one organosilicon compound having the formula (Ia):
(Si′O—)
x
Si—R (Ia)
wherein R is a linear, branched, cyclic or substituted alkyl group having from 1 to 50 carbon atoms;
wherein x is a number from 0 to 20;
wherein remaining free valences of Si are each independently (KA—O)—, SiO— or —Z;
wherein remaining free valences of Si′ are each independently (KA—O)—, SiO—, —R, or —Z;
wherein the Z's are each independently hydroxyl or alkoxy radicals; and
wherein each Si and Si′ in the shell B have not more than one R group attatched thereto.
Another embodiment of the present invention provides a composition, which includes the above nanocapsule and at least one selected from the group including a liquid, a curable synthetic resin, a precursor of a synthetic resin, and a mixture thereof.
Another embodiment of the present invention provides a process, which includes applying the above composition according to a substrate.
Another embodiment of the present invention provides a composition, which includes the above nanocapsule and a cured resin, wherein the cured resin includes at least one selected from the group including acrylate, methacrylate, epoxide, epoxy resin, polyurethane, polyurethane resin, unsaturated polyester, unsaturated polyester resin, epoxy acrylate, polyester acrylate, urethane acrylate, silicone acrylate, and mixtures thereof.
Another embodiment of the present invention provides a coated article, which includes the above composition in contact with a substrate.
Another embodiment of the present invention provides n organosilicon nanocapsule prepared by a process, which includes reacting:
(i) at least one nanoscale oxide and/or mixed oxide (KA—O) particle of at least one metal or semimetal selected from the group including main groups two to six of the Periodic Table of the Elements, transition groups one to eight of the Periodic Table of the Elements, lanthanides, and combinations thereof, with
(ii) at least one alkyltrialkoxysilane having the formula (II)
(Z)
3
Si—R (II)
wherein the Z's are identical or different and are each independently hydroxyl or alkoxy radicals;
wherein R is a linear, branched, cyclic or substituted alkyl group having from 1 to 50 carbon atoms; and
(iii) optionally, a monomeric and/or oligomeric silicic ester which carries at least one selected from the group including methoxy, ethoxy, n-propoxy, i-propoxy group, and combinations thereof and has an average degree of oligomerization of from 1 to 50, and
(iv) optionally, an organofunctional siloxane whose functionalities are identical or different and in which each silicon atom carries at least one functionality selected from the group including n-alkyl, i-alkyl, cycloalkyl, fluoroalkyl, chloroalkyl, bromoalkyl, iodoalkyl, alkoxyalkyl, mercaptoalkyl, aminoalkyl, and combinations thereof, and remaining free valences of the silicon atoms in the siloxane are satisfied by methoxy or ethoxy or hydroxyl groups, and
(v) optionally, a further organofunctional silane selected from the group including aminoalkylalkoxysilane, mercaptoalkylalkoxysilane, epoxyalkoxysilane, alkoxyalkylalkoxysilane, fluoroalkylalkoxysilane, chloroalkylalkoxysilane, bromoalkylalkoxysilane and iodoalkylalkoxysilane, in situ in a liquid, a curable synthetic resin or a precursor of a curable synthetic resin. Another embodiment of the present invention provides a process for preparing an organosilicon nanocapsule, which includes reacting:
(i) at least one nanoscale oxide and/or mixed oxide (KA—O
Edelmann Roland
Monkiewicz Jaroslaw
Degussa - AG
Kiliman Leszek
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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