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...
Reexamination Certificate
2001-08-07
2004-08-17
Robertson, Jeffrey B. (Department: 1712)
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, C524S588000, C528S017000, C528S020000, C525S477000
Reexamination Certificate
active
06777471
ABSTRACT:
This application is an application under 35 U.S.C. Section 371 of International Application Number PCT/FR99/02933 filed on Nov. 26, 1999.
A subject-matter of the present invention is single-component organopolysiloxane compositions which are stable on storage in the absence of moisture and which crosslink to adherent and translucent elastomers in a thin layer (that is to say, within a thickness range in particular from 0.3 to 3 mm), the crosslinking being carried out from ambient temperature (that is to say, within a temperature range from 5° C. to 35° C.) and in the presence of moisture.
It is known to prepare compositions having these properties by blending mainly diorganopolysiloxane polymer(s) comprising end alkoxyl groups, inorganic filler(s) not generating opaqueness, silanes substituted by specific hydrolysable groups, agent(s) for improving adhesion and a curing (or crosslinking) catalyst.
Compositions of this type figure more especially in U.S. Pat. No. 5,674,936 and U.S. Pat. No. 5,698,653. The compositions in accordance with this prior art are formed by blending a diorganopolysiloxane polymer comprising end alkoxyl groups, a siliceous inorganic filler, a nonreactive diorganopolysiloxane polymer comprising end trialkylsiloxyl groups, a curing catalyst based on a tetraalkyl titanate and an agent for improving the adhesion consisting of a 1,3,5-tris(trialkoxysilyl)alkyl isocyanurate (in the case of U.S. Pat. No. 5,674,936) or of an epoxidized silane (in the case of U.S. Pat. No. 5,698,653).
The compositions in accordance with this prior art necessarily require the use, from the start, of an already functionalized diorganopolysiloxane polymer (comprising at least two alkoxyl groups at each chain end), which is obtained by reacting, in a separate preliminary stage, a tri- or a tetraalkoxysilane with a diorganopolysiloxane polymer comprising a hydroxyl group at each chain end in the presence of a catalyst. The compositions in accordance with this prior art necessarily also require the use of an agent for improving the adhesion.
An aim of the present invention is to provide novel single-component organopolysiloxane compositions which are obtained by starting directly from organopolysiloxane polymers comprising hydroxyl groups in their structures.
Another aim of the present invention is to provide single-component organopolysiloxane compositions of this type which will undergo in situ, during their preparation, a reaction for complete functionalization or functionalization which is as close as possible to the maximum degree of functionalization accessible and will exhibit, for this reason, a high level of stability on storage in cartons.
Yet another aim of the present invention is to provide single-component organopolysiloxane compositions which do not necessarily resort to the use of an agent for improving the adhesion and which make it possible to obtain, without use of such an agent, translucent elastomers with very good adhesion to various substrates, in particular plastics, such as, for example, poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA).
Yet another aim of the present invention is to provide single-component organopolysiloxane compositions which can be prepared by using, without distinction, a batchwise mode or a continuous mode.
The discovery has thus been made, and it is this which forms the subject-matter of the present invention, of single-component organopolysiloxane compositions which are stable on storage in the absence of moisture and which crosslink to translucent and adherent elastomers in the presence of moisture, characterized in that they are capable of being obtained by carrying out, in a single closed reactor with stirring, operating according to a batchwise mode or a continuous mode, successive stages 1 to 3 defined below:
stage 1: functionalization stage, during which:
(i) at least one reactive linear diorganopolysiloxane A comprising a hydroxyl group at each chain end, of formula:
in which:
the R
1
substituents, which are identical or different, each represent an aliphatic, or aromatic, saturated or unsaturated, substituted or unsubstituted, C
1
to C
13
monovalent hydrocarbonaceous radical;
n has a value sufficient to confer, on the diorganopolysiloxanes of formula (I), a dynamic viscosity at 25° C. ranging from 1 000 to 1 300 000 mPa·s;
(2i) and at least one hydroxylated organopolysiloxane resin B exhibiting, in its structure, at least two different units chosen from those of formulae (R
−
)
3
SiO
1/2
(M unit), (R
1
)
2
SiO
2/2
(D unit), R
1
SiO
3/2
(T unit) and SiO
2
(Q unit), at least one of these units being a T or Q unit and the R
1
radicals, which are identical or different, having the meanings given above with respect to the formula (I), the said resin having a content by weight of hydroxyl group ranging from 0.1 to 10%;
(3i) are reacted with at least one polyalkoxysilane C of formula:
(R
2
)
a
Si[(OCH
2
CH
2
)
b
OR
3
]
4−a
(II)
in which:
the R
2
substituent represents an aliphatic, cyclanic or aromatic, saturated or unsaturated, substituted or unsubstituted, C
1
to C
13
monovalent hydrocarbonaceous radical;
the R
3
symbols, which are identical or different, each represent a linear or branched C
1
to C
8
alkyl radical;
a is zero or 1;
b represents zero or 1;
(4i) the reaction of (i) and (2i) with (3i) being carried out in the presence of a catalytically effective amount of a functionalization catalyst D, with the exception of the use of an organic titanium derivative;
(5i) it being possible for the reaction medium of stage 1 additionally to comprise;
at least one aliphatic C
1
to C
3
alcohol &egr;; and/or
at least one nonreactive linear diorganopolysiloxane F of formula:
in which:
the R
1
substituents, which are identical or different, have the same meanings as those given above for the reactive diorganopolysiloxane A of formula (I);
m has a value sufficient to confer, on the polymers of formula (III), a dynamic viscosity at 25° C. ranging from 10 to 200 000 mPa·s;
stage 2: blending (or compounding) stage, during which:
(6i) an inorganic filler G based on amorphous silica in the form of a solid;
(7i) an effective amount of a curing catalyst H comprising at least one organic titanium derivative chosen from the group consisting of:
H1 monomers of formula:
Ti[(OCH
2
CH
2
)
c
OR
4
]
4
(IV)
in which:
the R
4
substituents, which are identical or different, each represent a linear or branched C
1
to C
12
alkyl radical;
c represents zero, 1 or 2;
with the conditions according to which, when the c symbol represents zero, the R
4
alkyl radical has from 2 to 12 carbon atoms and, when the c symbol represents 1 or 2, the R
4
alkyl radical has from 1 to 4 carbon atoms;
H2 polymers resulting from the partial hydrolysis of the monomers of formula (IV) in which the R
4
symbol has the abovementioned meaning with the c symbol representing zero;
(8i) optionally at least one nonreactive linear diorganopolysiloxane F corresponding to the formula (III) mentioned above; and
(9i) optionally at least one auxiliary agent I known to a person skilled in the art, which is generally chosen, when it is needed, according to the applications in which the compositions according to the present invention are employed;
are introduced in any order into the functionalization medium of stage 1, which is kept stirred;
stage 3: finishing stage, during which the base blend obtained, kept stirred, is subjected to a devolatilization operation carried out under a pressure below atmospheric pressure.
In accordance with a preferred arrangement of the invention, the following are used to prepare the single-component organopolysiloxane compositions, on the basis of 100 parts by weight of hydroxylated linear diorganopolysiloxane(s) A:
from 3 to 30 parts of hydroxlyated resin(s) B,
from 2 to 15 parts of polyalkoxysilane(s) C,
a catalytically effective amount of functionalization catalyst D,
from 0 to 2 parts of alcohol(s) E,
from 0 to 30 parts of nonreactive linear diorganopolysiloxane(s) F,
fr
Dalbe Bernard
Michiels Sylvie
Rhodia Chimie
Robertson Jeffrey B.
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