Emulsions of organosilicon compounds for imparting water...

Details Emulsions of organosilicon compounds for imparting water... Emulsions of organosilicon compounds for imparting water...

1998-09-30

2001-09-25

Wilson, Donald R. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C524S837000, C106S287110, C106S287160

Reexamination Certificate

active

06294608

ABSTRACT:

TECHNOLOGICAL FIELD
The invention relates to aqueous emulsions of organosilicon compounds containing alkoxy groups and organosilicon compounds containing aminoalkyl groups, and to a process for imparting water repellency to porous mineral building materials, building coatings, and to wood.
DESCRIPTION OF THE RELATED ART
Aqueous emulsions of organosilicon compounds are used in building protection, especially because of their outstanding action against impregnation by water and dirt, their environmental compatibility, and their physiological safety.
U.S. Pat. No. 4,757,106 describes the impregnation of neutral mineral building materials with an aqueous emulsion of polyorganosiloxanes having ammonium groups and polyorganosiloxanes having ethoxy groups. The water repellent effect is smaller on alkaline building materials since the ammonium groups are neutralized and the emulsion breaks. The polyorganosiloxane then scarcely penetrates into the building material.
Emulsions which contain, as an active ingredient, resin-like polyorganosiloxanes having alkoxy groups penetrate readily into porous building materials and impart good surface water repellency to them. However, dense building materials are only superficially and temporarily protected.
Although emulsions of alkylalkoxysilanes penetrate readily into building materials, these emulsions do not have a long shelf life. U.S. 4,877,654 describes buffered emulsions of alkylalkoxysilanes which, although exhibiting a long shelf life, are deposited too slowly, in particular in neutral building materials, and therefore impart water repellency poorly. This poor water repellency is noted particularly in the zone close to the surface.
Emulsions which contain resin-like polyorganosiloxanes having alkoxy groups and low molecular weight alkylalkoxysiloxanes or alkylalkoxysilanes as active ingredients are disclosed in U.S. Pat. No. 5,039,724. These emulsions are a compromise between a long shelf life and a water repellent action at the surface.
U.S. Pat. No. 5,196,054 describes an emulsion which, in addition to siloxanes and silanes containing alkyl and alkoxy groups, also contains a mixture or a reaction product of a silane containing aminoalkyl groups and &agr;,&ohgr;-hydroxypolydialkylsiloxane. Although these components result in more rapid formation of the hydrophobic character on the surface of the building material, they impede the penetration of the other active components into the deep pores of the building material.
SUMMARY OF THE INVENTION
It is the object of the invention to provide aqueous emulsions of organosilicon compounds for imparting water repellency to porous mineral building materials and building coatings, these emulsions exhibiting a long shelf life, and to provide a process for imparting water repellency to porous mineral building materials and coatings, a process which is particularly effective in the case of neutral and basic building materials and coatings, and which does not have the disadvantages of the emulsions described above. These objects are achieved by employing aqueous emulsions of organosilicon compounds containing alkoxy groups and organosilicon compounds containing aminoalkyl groups.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention relates to an aqueous emulsion which contains the components
(A) organosilicon compounds which are selected from
(A1) C
1
-C
20
-hydrocarbon-C
1
-C
6
-alkoxysilanes and
(A2) branched organopolysiloxanes containing C
1
-C
6
-alkoxy groups,
(B) organosilicon compounds which are selected from
(B1) C
1
-C
6
-alkoxysilanes containing aminoalkyl groups and
(B2) branched organosiloxanes containing aminoalkyl groups, and
(C) an emulsifier.
Preferably, the C
1
-C
20
-hydrocarbon-C
1
-C
6
-alkoxy-silanes (A1) have 1 or 2 identical or different, optionally halogen-substituted, monovalent C
1
-C
20
-hydrocarbon radicals bonded via SiC, and the other radicals are identical or different C
1
-C
6
-alkoxy radicals.
Examples of C
1
-C
20
-hydrocarbon radicals are alkyl radicals such as the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, and tert-pentyl radicals; hexyl radicals such as the n-hexyl radical; heptyl radicals such as the n-heptyl radical; octyl radicals such as the n-octyl radical and isooctyl radicals such as the 2,2,4-trimethylpentyl radical; nonyl radicals such as the n-nonyl radial; decyl radicals such as the n-decyl radical; and dodecyl radicals such as the n-dodecyl radical; cycloalkyl radicals such as cyclopentyl, cyclohexyl, 4-ethylcyclohexyl, and cycloheptyl radicals, norbornyl radicals and methylcyclohexyl radicals; alkenyl radicals such as the vinyl, allyl, n-5-hexenyl, 4-vinylcyclohexyl and 3-norbornenyl radicals; aryl radicals such as the phenyl, biphenylyl, naphthyl, anthryl, and phenanthryl radicals; alkaryl radicals such as o-, m-, and p-tolyl radicals, xylyl radicals and ethylphenyl radicals; aralkyl radicals such as the benzyl radical and the &agr;- and &bgr;-phenylethyl radicals. The unsubstituted C
1
-C
12
-alkyl radicals and the phenyl radical are particularly preferred.
Examples of halogen-substituted C
1
-C
20
-alkyl radicals are alkyl radicals substituted by fluorine, chlorine, bromine and iodine atoms, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2′,2′,2′-hexafluoroisopropyl radical and the heptafluoroisopropyl radical.
Examples of C
1
-C
6
-alkoxy radicals are the methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy radical; pentyloxy radicals such as the n-pentyloxy radical, and hexyloxy radicals such as the n-hexyloxy radical. The ethoxy radicals are particularly preferred. The alkoxy radicals may be substituted by halogen atoms, but this is not preferred.
The emulsion may contain a branched organopolysiloxane (A2) containing C
1
-C
6
-alkoxy groups or a mixture of a plurality of organopolysiloxanes (A2). The organopolysiloxanes (A2) may additionally contain hydroxyl groups, which facilitate binding to the building materials.
The organopolysiloxanes (A2) are preferably composed of units of the general formula (I)
R
x
⁢
Si
⁡
(
O
⁢
R
1
)
y
⁢
(
OH
)
z
⁢
O
4
-
x
-
y
-
z
2
,
(
I
)
in which
R denotes identical or different monovalent optionally halogen-substituted C
1
-C
20
-hydrocarbon radicals bonded via SiC,
R
1
denotes identical or different monovalent C
1
-C
6
-alkyl radicals,
x denotes the values 0, 1, 2 or 3, on average 0.8 to 1.8,
y denotes the values 0, 1, 2 or 3, on average 0.01 to 2.0, and
z denotes the values 0, 1, 2 or 3, on average 0.0 to 0.5, with the proviso that the sum of x, y and z is on average not more than 3.5, the organopolysiloxanes (A2) having at least one unit of the general formula (I) in which the sum of x, y and z has the values 0 or 1.
The organopolysiloxane (A2) preferably has a viscosity of 5 mm
2
/s to 50,000 m
2
/s, in particular 10 mm
2
/s to 5000 mm
2
/s, at 25° C.
Examples of the C
1
-
20
-hydrocarbon radicals are the examples of C
1
-C
20
-hydrocarbon radicals mentioned above in the case of the C
1
-C
20
-hydrocarbon-C
1
-C
6
-alkoxysilanes (A1).
Although not shown in the above formula, some of the radicals R may be replaced by hydrogen atoms bonded directly to silicon atoms. However, this is not preferred.
Examples of the radicals OR
1
are the C
1
-C
6
-alkoxy radicals mentioned above for C
1
-C
20
-hydrocarbon-C
1
-C
6
-alkoxysilanes (A1).
Preferably, x has an average value of 0.9 to 1.1. Preferably, y has an average value of 0.4 to 1.2. Preferably, z has an average value of 0.0 to 0.2.
Since the organopolysiloxanes (A2) are branched, they have at least one unit of the general formula (I) in which the sum of x, y and z has the values 0 or 1. Preferably, the organopolysiloxanes (A2) have at least 10 mol %, and in particular at least 30 mol % of units of the general formula (I) in which the sum of x, y and z has the values 0 or 1.
Examples of organosiloxanes (A2) are those which are obtainable by reacting methyltrichlorosilane and optionally a C
1
-C
8
-alkyltrichlorosilane or phenyltrich

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