Note: Descriptions are shown in the official language in which they were submitted.
1 3362 1 5
Mouldinq and Sealinq Compound
The present invention relates to a one-component moulding
and sealing compound, which is storable on excluding
moisture, but which is crosslinkable to elastomers in the
case of water access, whilst having an improved stability.
Moisture-hardening one-component moulding and sealing
compounds are already known per se. A known group of such
compounds contains as prepolymers, which are crosslinkable
by atmospheric moisture, compounds with term; n~ 1 silyl
10 groups having at least one hydrolyzable substituent at the
Si-atom. Such prepolymers and sealing compounds produced
therefrom are e.g. known from US Patent 3 971 751 and EP
application 217 289 published April 8, 1987.
15 In particular on incorporating larger quantities of
inorganic fillers, particularly thixotropic fillers, such
as micro-fine silica, problems occur. Particularly in the
case of prolonged storage, the compounds have an inadequate
stability and this can lead to a complete collapse of the
20 thixotropic characteristics. However, for practical uses a
stable sealant is vital and it must have no flow or
levelling tendency.
It has surprisingly been found that the stability of the
25 known sealing compounds can be significantly improved if an
isocyanate or a carboxylic acid chloride is added as
stabilizer. Particular preference is given to p-toluyl
sulphonyl isocyanate of formula I
CH3 ~ S2 ~ NCO
, .
- - -
- 2 - 133~215
but it is also possible to use other isocyanates, such as
toluylene diisocyanate (TDI ), diphenyl methane-4,4-
diisocyanate (MDI), naphthalene diisocyanate (NDI ),
isophorone diisocyanate ( IPDI ), hexamethylene diisocyanate
5 (HDI), etc. Preferred acid chlorides are benzoylchloride
and 3,5-dinitrobenzoyl chloride. Based on the total weight
of the compound, added quantities of approximately 0.01 to
1 and preferably 0.05 to 0.10% by weight are adequate for
obt~ini~g the desired stability. Hitherto p-toluyl
10 sulphonyl isocyanate, which is commercially available
under the name "Zusatzmittel TI" from Bayer AG, Leverkusen,
has only been used as an agent for trapping water traces in
polyurethane materials. This problem does not occur in the
case of the materials or compounds according to the
15 invention and no explanation can be given as to why said
compounds lead to the observed increase in the stability of
the highly filled sealants, without impairing other
characteristics of the compounds.
20 The silyl-modified prepolymers are polyethers, polyesters,
ether-ester block copolymers, vinyl polymers, diallyl
phthalates and their prepolymers, as well as diallyl
phthalate copolymers, which can in each case contain at
least one silyl group of the following formula II in the5 molecule 1 2
(R )a I
X -Si~ H- , (II)
in which Rl and R2, independently of one another, can
30 represent hydrogen atoms or alkyl, aryl or aralkyl radicals
with up to 10 carbon atoms, X a hydrolyzable group and a 0,
1 or 2. X can be a halogen atom or an alkoxy, aminoxy,
phenoxy, thioalkoxy, acyloxy, acid amide, mercapto or
ketoximato group. It is preferably an alkoxy group with 1
35 to 5 carbon atoms in the alkyl radical. A particularly
preferred silyl terminal group is the dimethoxymethylsilyl
~ 3 ~ 1 33621 5
group.
The prepolymer molecular weight can be between 500 and
20,000, preferably between 500 and 15,000. A particularly
5 preferred molecular weight is 3000 t~ 12,000. Particularly
preferred prepolymers are silyl-modified polyethers, which
can be obtained by hydrosilylation of polyethers with
olefinically unsaturated terminal groups, cf. US Patent
3 971 751. Suitable silyl-modified polyethers are those of
10 formula III
CH3 CH3 CH3
3 (CH2)3 - (0CH2 - CH ~ )n -(CH2)3 ~ Si - OCH3 III
OCH ~~ OCH3
For producing moisture-hardening moulding and sealing
compounds, organometallic tin compounds are added as
catalysts to the known silyl-modified polymers, e.g.
tin(II)octoate or dibutyl tin laurate and dibutyl tin
2~ maleate (US Patent 3 971 751). However, the use charac-
teristics of the present compounds are also influenced by
the choice of the organometallic tin compound. Particularly
preferred catalysts are the reaction products obtained at
approximately 150C of dibutyl tin oxide with dioctyl
25 phthalate and dibutyl tin acetate. Surprisingly dibutyl tin
dialkylates of C3 to C6-alcohols, particularly dibutyl tin
dibutylate are particularly suitable.
In addition, inorganic fillers such as carbon black,
30 calcium carbonate, titanium dioxide and the like, as well
as plasticizers, particularly phthalates, such as dioctyl
phthalate and butylbenzyl phthalate or phosphates, such as
tricresyl phosphate are added.
35 The preferred inorganic fillers according to the invention
are highly disperse silica and in particular fumed or
_ 4 _ l 3 3 6 2 1 5
precipitated silica which have a thixotropic effect and
whose thixotropic characteristics are retained even after
prolonged storage in the compounds according to the
invention. Finally the compounds can contain conventional
5 W-stabilizers and antioxydants (anti-agers). Amino
silanes, such as e.g. ~-glycidyloxypropyl or Y-aminopropyl-
trimethoxysilane are in particular used for improving the
adhesion to glass, metals, etc. They simultaneously trap
any moisture in the fillers, ensure a good storage
10 stability and to a certain extent act as a co-catalyst.
It has proved particularly advantageous in the production
of the inventive compounds, if the organometallic tin
compounds and the stabilizer are jointly added following
15 the mixing of the remaining components. This avoids the
collapse of the thixotropy which is otherwise frequently
encountered on adding tin compounds.
The following examples further illustrate the invention
20 without restricting the same.
Example l
Within the scope of this example, various organometallic
tin compounds were checked as regards their catalytic
25 activity. For this purpose, a basic mixture of the
following components was prepared:
30.0% by weight of a polyether prepolymer with dimethoxy-
methylsilyl terminal groups (viscosity 100-260 P),
6.34% dioctylphthalate,
30 11.83% titanium dioxide paste (52% TiO2 in dioctyl-
phthalate),
0.30% antioxydant (anti-ager),
0.30~ W-protective agent,
45.39% calcium carbonate,
35 4.34% hydrogenated castor oil.
In each case 200 g of the above basic mixture were filled
_ 5 l 3 3 62 1 ~
into a 310 ml cartridge and mixed with 0.2 to 0.8 g of the
particular catalyst composition to be tested. The mixture
was then stirred under vacuum for`approximately 2 minutes
in a cartridge mixing apparatus.
The sealants were then applied to glass plates or poly-
ethylene film-covered boards for determin;ng the skin
formation time (in minutes) and the surface tackiness
(after 24 hours). The results obtained are given in the
10 following Table 1. Apart from the reaction product of
dibutyl tin oxide with dioctyl phthalate (at 150C),
dibutyl tin dibutylate was surprisingly found to be very
effective. The tests also revealed that, apart from the
organometallic tin compound, a silane such as y-glycidyl-
15 oxypropyl-trimethoxysilane or y-aminopropyl-trimethoxy-
silane is particularly useful for obtaining good adhesion
characteristics and also for the storage stability.
1 33621 5
_
-- 6 -- '
,
,t
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~o I ~ O '
O O ~ + + a ~
- 3
O o I
V ~3
O ~ + +~ 3
u
o O I~ r
~ ~ o co
I I I ~o + + u~
o o
a~ ta
o o .
o
o ~ ~ .,
r~ I I I I i I o c,~3 ~ ~ Qr~
r
~ I_ o I ~ 1' 1' 1'
c~ _( c~ o ~
co . . . I I ~ + + ~ +
o o o
u~ +
0
o o c~
o
I I I o~ + +
o o
o o
c~
~o I I I ~ I +
,t O O
~ I
E~ O O O
~ ~ ` ~ ~ ~ + + - o o o
o o o ~ r ,t c
O O O
~O ~CS` CJ~ I ~ + I O
I I ~ + + ~
O O O +
c"
o
cs~ .
O l l ~ l O
r
o - .,
o oo i -~
I I ~ I o o
o o ~ o
o a~ ~ ,-
O I I I J, I ~ t` ` '
c~ ~ . ,
~ ~ ,t
~ o
r - c r o J
~ r c~
. `" ., ,~', ,r .' ~ ~ 8 ~ 8 o
o ,- ,-~ E ~ r
z ~ rt ~ ._r ~ . O U~
JJ ~ C~ rt ~ C ~ U~
U~ rrt~ O r~ ~ rt E ~ ~ ,t
V ~rt rt~5 -
;,_ C~ ~ + ~ + + O
_ 7 _ l 33621 5
ExamPle 2
Sealants A to D were produced which differ from one another
in that the sealants B to D additionally contain an
isocyanate or acid chloride:
A B C D
MS polymer* 20 A 19.00 19.00 19.00 19.00
10 MS polymer* 300 13.00 13.00 13.00 13.00
Dioctylphthalate 29.03 28.53 21.09 21.09
Di(N-methylbenzamido)-
15 methyl-ethoxysilane 0.50 0.50 0.50 0.50
Y-Aminopropyl-trimeth-
oxysilane 0.80 0.80 0.80 0.80
20 Vinyltrimethoxysilane 0.60 0.60 0.60 0.60
Antioxydant
(Anti-ager) 0.30 0.30 0.30 0.30
25 W -protective agent 0.30 0.30 0.30 .30
Highly disperse silica4.50 4.50 4.50 4.50
Calcium carbonate 24.52 24.52 32.06 32.06
Butyl tin dibutylate 0.70
Intermediate 1 6.75 6.75 6.75 6.75
Intermediate 2 - 1.20
Intermediate 3 - - 1.20
35 Intermediate 4 - - - 1.20 -
100.00 100.00 100.00 100.00
Intermediate
Dioctylphthalate 43.530
Iron oxides 56.470
100 . 00
* Bis[3-(methyldimethoxysilyl)propyl]-polyoxypropylene
- - 1 3 3 ~ 2 1 5
Intermediate 2 3 4
Dioctylphthalate 34.723 34.723 34.723
Dibutyl tin dibutylate58.333 58.333 58.333
p-Toluol sulphonyl
isocyanate 6.944
Diphenylmethane-4,4'-
diisocyanate - 6.944
Benzoylchloride - - 6.944
100.00 100.00 100.00
All the sealants had a very short skin formation time of 10 to
20 15 minutes and showed a good adhesion to different substrates.
However, the formulations differed significantly as regards
their stability. Whereas even after prolonged storage sealants B
to D had an excellent stability, sealant A proved not to be
stable. Despite the addition of thixotropic highly disperse
25 silica, the thixotropic characteristics had disappeared after
only a short time, so that on a smooth substrate sealant A
flowed, i.e. had a levelling tendency.
