Building compositions which comprise hydrophobicizing...

Details Building compositions which comprise hydrophobicizing... Building compositions which comprise hydrophobicizing...

1998-11-04

2001-07-31

Cain, Edward J. (Department: 1714)

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...

C524S493000

Reexamination Certificate

active

06268423

ABSTRACT:

TECHNICAL FIELD
The invention relates to building compositions which contain hydrophobicizing powders comprising organosilicon compounds.
BACKGROUND ART
Powders which comprise organosilicon compounds and are redispersible in water are known from DE-A-19535833. The powders are based on vinyl acetate copolymers and comprise on their surface not only dispersants but also, as hydrophobicizing agents, organosilicon compounds on water-insoluble support materials. This reduces the blocking tendency while maintaining the redispersibility of the redispersible powders. Blocking impairs the redispersibility and also the storage stability of the redispersible powders. When stored at high atmospheric humidity, such redispersible powders display a tendency toward caking, and do not hydrophobicize building compositions with which they have been mixed.
Powders which comprise organosilicon compounds and are not redispersible in water are known from GS-A-1217813. The powders are produced from lime and an emulsion of organopolysiloxane resin. The lime powders described there are used as hydrophobicizing agents for compositions comprising inorganic binders or consisting of such binders, and also as binders in mortars and renders.
The lime powders easily lead to caking and thickening of the compositions with which they have been mixed. In addition lime acts as a catalyst for reactive organosilicon compounds. Owing to their high alkalinity, the lime powders are only suitable for hydraulically setting compositions comprising lime and/or cement, or for gypsum plaster. The hydrophobicizing action is too low.
DISCLOSURE OF INVENTION
It is an object of the invention to make available building compositions which comprise pulverulent hydrophobicizing agents which do not have a tendency toward caking and can be metered easily.
BEST MODE FOR CARRYING OUT THE INVENTION
The invention provides building compositions which comprise hydrophobicizing powders whose essential components include:
A) silica as support material and
B) a hydrophobicizing component which is liquid at 10° C. and comprises
B1) organosilicon compound(s) and, if desired,
B2) solvent(s) and/or
B3) water and emulsifier,
with the proviso that the powders contain from 5 to 80% by weight of organosilicon compound, based on the total weight of the powder.
The building compositions quickly achieve high water repellency. In contrast to hydrophobicized redispersible dispersion powders, the present hydrophobicizing powders contain no reemulsifiable constituents, and thus the development of the water repellency is quicker and more distinct.
The hydrophobicizing powders are not dispersible and are therefore not coated with dispersants which display a tendency toward caking. The hydrophobicizing powders are free-flowing and do not form lumps even after prolonged storage in air saturated with water vapor.
The sum of (A) silica and organosilicon compound, organic solvent, water and emulsifier of the liquid hydrophobicizing component (B) is preferably at least 90% by weight, in particular at least 95% by weight, of the hydrophobicizing powder.
As support material (A), it is possible to use, for example, pyrogenic silica or precipitated silica. These types of silica are finely divided and preferably have a BET surface area of at least 50 m
2
/g, in particular at least 100 m
2
/g.
The organosilicon compounds (B1) present in the hydrophobicizing powders are preferably selected from the group consisting of
(B1.1) C
1
-C
20
-alkyl-C
1
-C
6
-alkoxysilanes,
(B1.2) organosiloxanes containing groups selected from among hydrocarbon, hydroxyl, C
1
-C
6
-alkoxy and aminoalkyl groups and
(B1.3) alkali metal siliconates.
Preferably, the C
1
-C
20
-hydrocarbon-C
1
-C
6
-aloxysilanes (B1.1) contain 1 or 2 identical or different, unsubstituted or halogen-substituted, SiC-bonded mono-valent C
1
-C
20
-hydrocarbon radicals 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, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl radical; 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 iso-octyl radicals such as the 2,2,4-trimethylpentyl radical; nonyl radicals such as the n-nonyl radical; decyl radicals such as the n-decyl radical and dodecyl radicals such as the n-dodecyl radical; cycloalkyl radicals such as the cyclopentyl, cyclohexyl, 4-ethylcyclohexyl, cycloheptyl, norbornyl 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-, p-tolyl radicals, xylyl radicals and ethylphenyl radicals; aralkyl radicals such as the benzyl radical and the &agr;- and &bgr;-phenylethyl radicals. Particular preference is given to unsubstituted C
1
-C
12
-alkyl radicals and the phenyl radical.
Examples of halogen-substituted C
1
-C
20
-alkyl radicals are fluorine-, chlorine-, bromine- and iodine-substituted alkyl radicals, e.g. the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2′,2′,2′-hexafluoroisopropyl radical and the heptafluoroisopropyl radical.
Particular preference is given to unsubstituted C
1
-C
20
-alkyl radicals and the phenyl radical.
Examples of C
1
-C
6
-alkoxy radicals are the methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy radicals; 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 organosiloxanes (B1.2) are preferably built up of units of the formula (I)
R
v
⁢
Si
⁡
(
OH
)
x
⁢
(
O
⁢
R
1
)
y
⁢
R
z
2
⁢
O
4
-
v
-
x
-
y
-
z
2
(
I
)
where
R is a monovalent, unsubstituted or halogen-substituted, SiC-bonded C
1
-C
20
-hydrocarbon radical,
R
1
is a hydrogen atom or a monovalent C
1
-C
6
-allyl radical,
R
2
is a monovalent, unsubstituted or halogen-substituted, SiC-bonded aminoalkyl radical having from 1 to 30 carbon atoms,
v is 0, 1, 2 or 3, on average from 0.3 to 2.0,
x is 0 or 1, on average from 0.0 to 1.0,
y is 0, 1, 2 or 3, on average from 0.0 to 1.5 and
z is 0, 1, 2 or 3, on average from 0.0 to 0.8,
with the proviso that the organosiloxanes (B1.2) have at least one unit of the formula (I) in which the sum of x, y and z is at least 1.
Preferably, the sum of v, x, y and z is on average from 0.01 to 3.0.
Examples of the C
1
-C
20
-hydrocarbon radicals R are the examples of C
1
-C
20
-hydrocarbon radicals given above for the C
1
-C
20
-hydrocarbon-C
1
-C
6
-alkoxysilanes (B1.1).
Although not indicated in the above formula, some of the radicals R can be replaced by hydrogen atoms bound 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 (B1.1).
Radical R
2
is preferably a radical of the formula (II)
R
2
3
NR
4
−  (II)
where
R
3
is a hydrogen atom or a monovalent, substituted or unsubstituted C
1
-C
10
-hydrocarbon radical or C
1
-C
10
-aminohydrocarbon radical and
R
4
is a divalent C
1
-C
15
-hydrocarbon radical.
Examples of radical R
3
are the examples of hydrocarbon radicals given for radical R and also amino-substituted hydrocarbon radicals such as aminoalkyl radicals, particular preference being given to the aminoethyl radical. Preferably, at least one hydrogen atom is bound to each nitrogen atom in the radicals of the formula (II).
Radical R
4
is preferably a divalent hydrocarbon radical having from 1 to 10 carbon atoms, particularly preferably from 1 to 4 carbon atoms; in particular, it is the n-propylene radical. Examples of radical R
4
are the methylene, ethylene, propylene, butylene, cyclohexylene, octadecylene, pheny

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