Aqueous emulsions of functional alkoxysilanes and condensed oligomers thereof, their preparation and use for surface treatment

An aqueous oil-in-water emulsion, comprising:

• from 1 to 70% by weight, based on the total weight of the emulsion, of a condensed oligomer of a functional alkoxysilane;
• an organoalkoxysiloxane;
• a combination thereof;
• or a mixture of a functional alkoxysilane and at least one of a condensed oligomer thereof and an organoalkoxysiloxane;
• an emulsifier;
• and
• water,
• wherein
• the emulsion has a pH of from 5 to 9;
• the emulsion has a disperse phase having a mean droplet size of from 0.1 to 0.3 μm;
• the width of the droplet size distribution, expressed as
• D
• ⁢
• ⁢
• 90
• -
• D
• ⁢
• ⁢
• 10
• D
• ⁢
• ⁢
• 50
• ,
• is from 0.6 to 1.2;
• said D50 has a value of from 0.1 to 0.3 um, wherein the D50 represents the diameter of that droplet is larger than 50% by weight of all droplets and smaller than 50% by weight of all droplets;
• said emulsifier comprises a silicon-functional surfactant represented by
• where
• each R1and R2 is identical or different and is a straight-chain or branched C1-C20-alkyl group or a phenyl group,
• R3 is an C1-C10-alkyl group,
• p is an integer of from 0 to 3, and
• Ts is a surfactant radical represented by
• where
• n is an integer of from 3 to 15,
• m is an integer of from 3 to 50,
• l is an integer of from 3 to 25,
• R4 is H, a C1-C20-alky group, a C2-C36-alkenyl group, a C5-C8-cycloalkyl group, or a C7-C36-aralkyl group;
• said emulsifier optionally further comprises is at least one member selected from the group consisting of
• an alkylsulfate having a C8-C18-alkyl radical,
• an alkyl ether sulfate having a C8-C18-alkyl radical as hydrophobic radical and from 1 to 40 ethylene oxide (EO) or propylene oxide (PO) units,
• an alkaryl ether sulfate having a C8-C18-alkyl radical as hydrophobic radical and from 1 to 40 ethylene oxide (EO) or propylene oxide (PO) units,
• an alkylsulfonate having a C8-C18-alkyl radical,
• an alkarylsulfonate having a C8-C18-alkyl radical,
• a monoester of sulfosuccinic acid with a monohydric alcohol having from 5 to 15 carbon atoms,
• a monoester of sulfosuccinic acid with an alkylphenol having from 5 to 15 carbon atoms,
• an alkali metal salt of a carboxylic acid having from 8 to 20 carbon atoms in the alkyl, aryl, alkaryl or aralkyl radical,
• an ammonium salt of a carboxylic acid having from 8 to 20 carbon atoms in the alkyl, aryl, alkaryl or aralkyl radical,
• an alkylphosphate having from 8 to 20 carbon atoms in the organic radical,
• an alkarylphosphate having from 8 to 20 carbon atoms in the organic radical,
• an alkyl ether phosphate having from 8 to 20 carbon atoms in the alkyl radical and from 1 to 40 EO units,
• an alkaryl ether phosphate having from 8 to 20 carbon atoms in the alkaryl radical and from 1 to 40 EO units,
• an addition product of an alkylamine having C8-C22-alkyl radicals with ethylene oxide or propylene oxide, and
• an alkyl polyglycoside having a linear or branched, saturated or unsaturated C8-C24-alkyl radical and an oligoglycoside radical having from 1 to 10 hexose or pentose units;
• and
• said condensed oligomer of the functional alkoxysilane is at least one compound represented by
• where
• each R1group is, independently, a C3-C18-alkyl group, a halogen- or amino-substituted C3-C18-alkyl group, a vinyl group, a mercaptoalkyl group, a methacryloxyalkyl group, an acryloxyalkyl group, an alkylaminoalkyl group, a dialkylaminoalkyl group, a diethyleneaminoalkyl group, a triethyleneaminoalkyl group, a glycidyloxyalkyl group, a bisalkoxysilylalkyl group, a monosulfane or a polysulfane,
• each R2 group is, independently, a hydrogen atom or an alkyl radical having from 1 to 6 carbon atoms, and
• n represents the degree of oligomerization and is an integer of from 2 to 20, or
• is at least one compound represented by
• where
• m and n are identical or different and are each from 0 to 20, with the proviso that (n+m)≧2,
• each R and R2 group is, independently, hydrogen, a C1-C18-alkyl group, a halogen- or amino-substituted C1-C18-alkyl group, a phenyl group, a vinyl group, a mercaptoalkyl group, a methacryloxyalkyl group, an acryloxyalkyl group, an alkylaminoalkyl group, a dialkylaminoalkyl group, a diethyleneaminoalkyl group, a triethyleneaminoalkyl group, a glycidyloxyalkyl group, a bisalkoxysilylalkyl group, a monosulfane or a polysulfane, and
• each R1group is, independently, a hydrogen atom or an alkyl radical having from 1 to 6 carbon atoms.