U.S. patent application number 13/354976 was filed with the patent office on 2012-07-19 for anti-soil silicone varnish compositions and support substrates treated therewith.
This patent application is currently assigned to Rhodia Chimie. Invention is credited to Laurent DUMONT, Francis LAFAYSSE, Marilyne QUEMIN.
Application Number | 20120183698 13/354976 |
Document ID | / |
Family ID | 32480204 |
Filed Date | 2012-07-19 |
United States Patent
Application |
20120183698 |
Kind Code |
A1 |
QUEMIN; Marilyne ; et
al. |
July 19, 2012 |
ANTI-SOIL SILICONE VARNISH COMPOSITIONS AND SUPPORT SUBSTRATES
TREATED THEREWITH
Abstract
Silicone compositions, particularly for the production of
anti-fouling varnishes which may be applied to flexible or bulk
supports to provide an anti-fouling silicone varnish for textiles
coated with elastomeric silicones which is economical, adhesive,
low-slip and glossy; these are crosslinked silicone compositions
comprising: A. at least one alkenylsilane, B. at least one
catalytic system which comprises: B/1 at least one organometallic
condensation catalyst, B/2 at least one metal M chelate and/or one
metal alkoxide of general formula M(OJ).sub.n, wherein n=valence of
M and J=linear or branched C.sub.1-C.sub.8 alkyl radical, M being
selected from among: Ti, Zr, Ge and Al, C. at least one ultrafine
filler, D. optionally, at least one arylsilane other than A. E.
optionally, at least one other silane other than A. and other than
D., F. optionally, at least one thickening agent and G. optionally,
at least one functional additive.
Inventors: |
QUEMIN; Marilyne; (Lyon,
FR) ; DUMONT; Laurent; (La Motte Servolex, FR)
; LAFAYSSE; Francis; (Lyon, FR) |
Assignee: |
Rhodia Chimie
Boulogne-Billancourt-Cedex
FR
|
Family ID: |
32480204 |
Appl. No.: |
13/354976 |
Filed: |
January 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12068453 |
Feb 6, 2008 |
8153206 |
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13354976 |
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11166218 |
Jun 27, 2005 |
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12068453 |
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PCT/FR2003/003616 |
Dec 8, 2003 |
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11166218 |
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Current U.S.
Class: |
427/386 ;
427/387 |
Current CPC
Class: |
D06M 15/3568 20130101;
Y10T 428/31663 20150401; C09D 4/00 20130101; C09D 183/04 20130101;
D06N 3/183 20130101; C09D 4/00 20130101; Y10T 442/2279 20150401;
D06N 3/128 20130101; D06M 15/643 20130101; C08K 5/0091 20130101;
C09D 183/04 20130101; C08G 77/20 20130101; C08L 2666/52
20130101 |
Class at
Publication: |
427/386 ;
427/387 |
International
Class: |
B05D 3/10 20060101
B05D003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2002 |
FR |
02/16710 |
Claims
1. A process for varnishing a support substrate other than an
architectural textile, the process comprising: (a) forming a top
coat layer of a varnish composition onto a surface of a support
substrate comprising a silicone or silicone elastomer, wherein the
varnish composition comprises: (A) at least one alkenylsilane; (B)
at least one catalytic system comprising: (B)/1 at least one
organometallic condensation catalyst; (B)/2 at least one metal M
chelate and/or at least one metal alkoxide of formula M(OJ).sub.n,
wherein n=valence of M, J=linear or branched C.sub.1-C.sub.8 alkyl
radical, and M is selected from the group consisting of Ti, Zr, Ge
and Al; wherein said catalyst system comprises (B)/2 or a
combination of (B)/1 and (B)/2; (C) at least one ultrafine filler
having a mean particle diameter of less than or equal to 0.5 .mu.m;
(D) optionally, at least one arylsilane other than (A); (E)
optionally, at least one other silane other than (A) and other than
(D); (F) optionally, at least one thickening agent; and (G)
optionally, at least one functional additive; and (b) cross-linking
the top coat layer of the varnish composition to form an outer
layer of cross-linked varnish on said substrate; wherein the
varnish composition forming the top coat layer has a dynamic
viscosity .eta. expressed in mPass at 25.degree. C.) of between 2
and 500, inclusive.
2. The process as defined by claim 1, wherein the at least one
alkenylsilane is selected from the group consisting of: (a)
organoalkenylsilane monomer(s) comprising, per molecule, at least
one alkenyl group; (b) the oligomers or condensates of said
monomer(s) (a); (c) the hydrolyzates obtained from said monomer(s)
(a); and (d) mixtures thereof.
3. The process as defined by claim 2, wherein the
organoalkenylsilane monomer is selected from the group consisting
of vinyl alkoxysilanes, allylalkoxysilanes,
(meth)acryloyloxy(alkoxy)silanes and an organoalkenylsilane monomer
having the formula: ##STR00003## in which: the radicals R.sup.10,
R.sup.20 and R.sup.30, which may be identical or different, are
each hydrogen, or a hydrocarbon radical; L is an alkylene radical;
L.sub.1 is a valency bond or oxygen; R.sup.40 and R.sup.50, which
may be identical or different, are each an alkyl radical; x'=0 or
1; and x=0 to 2.
4. The process as defined by claim 1, wherein at least one of the
following conditions (a)-(c) is met: (a) said at least one
ultrafine filler having a mean particle diameter of less than or
equal to 0.5 .mu.m is selected from the group consisting of
siliceous fillers which comprise silica powders, colloidal silicas,
combustion and precipitated silicas and mixtures thereof,
suspensions of nanometric fillers, other inorganic fillers which
comprise TiO.sub.2, Al.sub.2O.sub.3 mica, and mixtures thereof; (b)
said at least one arylsilane other than (A) is selected from the
group consisting of phenyltrialkoxysilanes,
phenylalkyldialkoxysilanes and mixtures thereof; and (c) said at
least one other silane other than (A) and other than (D) is
selected from the group of the functionalized silanes comprising,
per molecule, one or more functional groups which are identical to
or different from one another and which are selected from the group
consisting of the following functional groups: hydroxyl, amino
(primary, secondary and tertiary amine, optionally included in a
ring, in isocyanurate groups and HALS groups of the piperidine and
other type), epoxy, (meth)acrylo and ureido.
5. A process for varnishing a support substrate other than an
architectural textile, the process comprising: (a) forming a top
coat layer of a varnish composition onto a surface of a support
substrate comprising a silicone or silicone elastomer, wherein the
varnish composition comprises: (A) at least one alkenylsilane; (B)
at least one catalytic system comprising: (B)/1 at least one
organometallic condensation catalyst; (B)/2 at least one metal M
chelate and/or at least one metal alkoxide of formula M(OJ).sub.n,
wherein n=valence of M, J=linear or branched C.sub.1-C.sub.8 alkyl
radical, and M is selected from the group consisting of Ti, Zr, Ge
and Al; wherein said catalyst system comprises (B)/2 or a
combination of (B)/1 and (B)/2; (C) at least one ultrafine filler
having a mean particle diameter of less than or equal to 0.5 .mu.m;
(D) optionally, at least one arylsilane other than (A); (E)
optionally, at least one other silane other than (A) and other than
(D); (F) optionally, at least one thickening agent; and (G)
optionally, at least one functional additive; and (b) cross-linking
the top coat layer of the varnish composition to form an outer
layer of cross-linked varnish on said substrate; wherein the
varnish composition forming the top coat layer has a dynamic
viscosity .eta. (expressed in MPass at 25.degree. C.) of between 5
and 200, inclusive.
6. The process as defined by claim 5, wherein the at least one
alkenylsilane is selected from the group consisting of: (a)
organoalkenylsilane monomer(s) comprising, per molecule, at least
one alkenyl group; (b) the oligomers or condensates of said
monomer(s) (a); (c) the hydrolyzates obtained from said monomer(s)
(a); and (d) mixtures thereof.
7. The process as defined by claim 6, wherein the
organoalkenylsilane monomer is selected from the group consisting
of vinyl alkoxysilanes, allylalkoxysilanes,
(meth)acryloyloxy(alkoxy)silanes and an organoalkenylsilane monomer
having the formula: ##STR00004## in which: the radicals R.sup.10,
R.sup.20 and R.sup.30, which may be identical or different, are
each hydrogen, or a hydrocarbon radical; L is an alkylene radical;
L.sub.1 is a valency bond or oxygen; R.sup.40 and R.sup.50, which
may be identical or different, are each an alkyl radical; x'=0 or
1; and x=0 to 2.
8. The process as defined by claim 5, wherein at least one of the
following conditions (a)-(c) is met: (a) said at least one
ultrafine filler having a mean particle diameter of less than or
equal to 0.5 .mu.m is selected from the group consisting of
siliceous fillers which comprise silica powders, colloidal silicas,
combustion and precipitated silicas and mixtures thereof,
suspensions of nanometric fillers, other inorganic fillers which
comprise TiO.sub.2, Al.sub.2O.sub.3 mica, and mixtures thereof; (b)
said at least one arylsilane other than (A) is selected from the
group consisting of phenyltrialkoxysilanes,
phenylalkyldialkoxysilanes and mixtures thereof; and (c) said at
least one other silane other than (A) and other than (D) is
selected from the group of the functionalized silanes comprising,
per molecule, one or more functional groups which are identical to
or different from one another and which are selected from the group
consisting of the following functional groups: hydroxyl, amino
(primary, secondary and tertiary amine, optionally included in a
ring, in isocyanurate groups and HALS groups of the piperidine and
other type), epoxy, (meth)acrylo and ureido.
9. A process for varnishing a support substrate other than an
architectural textile, the process comprising: (a) forming a top
coat layer of a varnish composition onto a surface of a support
substrate comprising a silicone or silicone elastomer, wherein the
varnish composition comprises: (A) at least one alkenylsilane; (B)
at least one catalytic system comprising: (B)/1 at least one
organometallic condensation catalyst; (B)/2 at least one metal M
chelate and/or at least one metal alkoxide of formula M(OJ).sub.n,
wherein n=valence of M, J=linear or branched C.sub.1-C.sub.8 alkyl
radical, and M is selected from the group consisting of Ti, Zr, Ge
and Al; Wherein said catalyst system comprises (B)/2 or a
combination of (B)/1 and (B)/2; (C) at least one ultrafine filler
having a mean particle diameter of less than or equal to 0.5 .mu.m;
(D) optionally, at least one arylsilane other than (A); (E)
optionally, at least one other silane other than (A) and other than
(D); (F) optionally, at least one thickening agent; and (G)
optionally, at least one functional additive; and (b) cross-linking
the top coat layer of the varnish composition to form an outer
layer of cross-linked varnish on said substrate; wherein the
varnish composition forming the top coat layer has a dynamic
viscosity .eta. (expressed in MPass at 25.degree. C.) of between 10
and 150, inclusive.
10. The process as defined by claim 9, wherein the at least one
alkenylsilane is selected from the group consisting of: (a)
organoalkenylsilane monomer(s) comprising, per molecule, at least
one alkenyl group; (b) the oligomers or condensates of said
monomer(s) (a); (c) the hydrolyzates obtained from said monomer(s)
(a); and (d) mixtures thereof.
11. The process as defined by claim 10, wherein the
organoalkenylsilane monomer is selected from the group consisting
of vinyl alkoxysilanes, allylalkoxysilanes,
(meth)acryloyloxy(alkoxy)silanes and an organoalkenylsilane monomer
having the formula: ##STR00005## in which: the radicals R.sup.10,
R.sup.20 and R.sup.30, which may be identical or different, are
each hydrogen, or a hydrocarbon radical; L is an alkylene radical;
L.sub.1 is a valency bond or oxygen; R.sup.40 and R.sup.50, which
may be identical or different, are each an alkyl radical; x'=0 or
1; and x=0 to 2.
12. The process as defined by claim 9, wherein at least one of the
following conditions (a)-(c) is met: (a) said at least one
ultrafine filler having a mean particle diameter of less than or
equal to 0.5 .mu.m is selected from the group consisting of
siliceous fillers which comprise silica powders, colloidal silicas,
combustion and precipitated silicas and mixtures thereof,
suspensions of nanometric fillers, other inorganic fillers which
comprise TiO.sub.2, Al.sub.2O.sub.3 mica, and mixtures thereof; (b)
said at least one arylsilane other than (A) is selected from the
group consisting of phenyltrialkoxysilanes,
phenylalkyldialkoxysilanes and mixtures thereof; and (c) said at
least one other silane other than (A) and other than (D) is
selected from the group of the functionalized silanes comprising,
per molecule, one or more functional groups which are identical to
or different from one another and which are selected from the group
consisting of the following functional groups: hydroxyl, amino
(primary, secondary and tertiary amine, optionally included in a
ring, in isocyanurate groups and HALS groups of the piperidine and
other type), epoxy, (meth)acrylo and ureido.
Description
CROSS-REFERENCE TO PRIORITY/PCT APPLICATIONS
[0001] This application is a continuation of earlier U.S.
application Ser. No. 12/068,453, filed Feb. 6, 2008, now allowed,
which is a continuation of U.S. application Ser. No. 11/166,218,
filed Jun. 27, 2005, now abandoned, which is a continuation of
PCT/FR 2003/003616, filed Dec. 8, 2003 and designating the United
States (published in the French language on Aug. 12, 2004 as WO
2004/067613 A1; the title and abstract were also published in
English), which claims priority under 35 U.S.C. .sctn.119 of FR
02/16710, filed Dec. 26, 2002, each hereby expressly incorporated
by reference and each assigned to the assignee hereof.
CROSS-REFERENCE TO COMPANION APPLICATIONS
[0002] Our application Ser. No. 11/166,380 [Attorney Docket No.
1022702-000126], filed Jun. 27, 2005 concurrently with our
application Ser. No. 11/166,218, now U.S. Pat. No. 7,790,785, and
its continuation application Ser. No. 12/318,843, filed Jan. 9,
2009, now U.S. Pat. No. 7,868,056.
BACKGROUND OF THE INVENTION
[0003] 1. Technical Field of the Invention
[0004] The present invention relates to polymer coatings or
varnishes capable of conferring resistance to soiling on supports
which may be at least partially composed of silicone.
[0005] The support substrates concerned are various and can, in
particular, be composed:
[0006] of flexible supports, in particular fibrous supports, which
may or may not be woven, coated with at least one layer for
mechanical strengthening or protection based on the coating
polymer, for example of the silicone elastomer type;
[0007] of supports in the massive form made of silicone and/or
coated with one or more silicone layers, for example components
made of metal, of plastic or ceramic (composite components, such as
electrical insulators, e.g.,);
[0008] or else of polymer or elastomer supports, in particular
plastic films, such as, for example, protective packaging
films.
[0009] The present invention also relates to processes for the
application to various supports of an anti-soil varnish.
[0010] Too, this invention relates to supports coated with such
anti-soil varnishes and in particular flexible supports, such as
textile cloths optionally coated with a layer of silicone
elastomer, the anti-soil varnish being applied to the layer of
silicone elastomer, such cloths being useful for the
manufacture:
[0011] 1. of architectural textiles (components of textile
architecture);
[0012] 2. or else of flexible supports other than architectural
textiles.
[0013] As regards the field of application 1., it should be
appreciated that, throughout the present account and within the
meaning of the present invention, the term "architectural textile"
means a woven fabric or nonwoven fabric and more generally in the
fibrous support intended, after coating, for the preparation:
[0014] of shelters, of mobile structures, of textile constructions,
of partitions, of flexible doors, of tarpaulins, of tents, of
stands or of marquees;
[0015] of furniture, of cladding, of advertising displays, of
windbreaks or of filter panels;
[0016] of solar protection devices, of ceilings and of blinds.
[0017] As regards the field of application 2., it will be
appreciated that these flexible supports other than architectural
textiles can, for example, be those intended for the manufacture,
of in particular:
[0018] airbags used for the protection of the occupants of a
vehicle,
[0019] glass braids (woven glass sheaths for thermal and dielectric
protection for electrical wires),
[0020] conveyor belts, fire barrier fabrics or thermal insulation
fabrics,
[0021] clothes,
[0022] compensators (flexible sealing sleeves for pipe work).
[0023] Silicone elastomer coatings on textile supports, due to the
intrinsic properties of silicones, already impart numerous
advantages on the composites thus formed, namely, inter alia:
[0024] flexibility,
[0025] mechanical strength,
[0026] thermal stability,
[0027] release properties,
[0028] and longevity.
[0029] However, in the field of textile architecture, which
constitutes an important application for the above said composites,
other requirements have been formulated, which are in particular
the following:
[0030] resistance to soiling substances,
[0031] good characteristics with regard to appearance,
[0032] especially with respect to the coloring and the gloss,
[0033] ability to adhesively bond, to make it possible to easily
assemble the composites two by two,
[0034] low sliding coefficient in order to favor the handling of
the composite,
[0035] good cohesion of the composite.
[0036] These properties can be provided by an appropriate surface
coating. The general problem and the basis of the invention is thus
the development of a silicone varnish capable of fulfilling this
role, in particular as regards the anti-soil properties.
[0037] However, before satisfying the requirements relating to the
final applications targeted for the composite, it is important for
this varnish to furthermore meet upstream specifications, namely,
in particular:
[0038] to be able to be easily spread over a silicone layer, indeed
even a nonsilicone layer (for example polyvinyl chloride,
polyurethane or polyamide),
[0039] to adhere perfectly to this silicone or nonsilicone
layer,
[0040] and more generally to be easy and economical to employ
industrially.
[0041] 2. Description of Background and/or Related and/or Prior
Art
[0042] WO-A-00/59992 discloses silicone compositions for use in
particular for the preparation of varnishes which can be applied to
supports for which it is desired to reduce the coefficient of
friction. One of these compositions comprises at least one
polyorganosiloxane A (POS) which can be crosslinked via
crosslinking functional groups (CFGs) by the cationic and/or
radical route and an initiator C selected from among onium borates,
wherein it additionally comprises POS D molecules substituted by
secondary functional groups (SFGs) carried by silicon atoms and
selected from those comprising at least one alkoxy and/or epoxy
and/or carboxyl unit, and optionally a filler (e.g., silica).
##STR00001##
[0043] These compositions can additionally comprise fillers and in
particular siliceous fillers, which can, for example, be:
[0044] combustion or pyrogenic silicas treated with
hexamethyldisilazane or with octamethylcyclotetrasiloxane (specific
surface up to approximately 300 m.sup.2/g), fumed silicas, ground
synthetic or natural fibers (polymers), calcium carbonates, talc,
clays, titanium dioxides, and the like.
[0045] Such compositions are used as anti-soil varnishes for RTV
silicone coatings of fabrics for air bags, for thermal transfer
ribbons or for packaging films.
[0046] Such varnishes are not the most effective in terms of
anti-soil properties and can be improved in terms of sliding
coefficient. In addition, they require the use of specific
silicones which can be crosslinked by cationic routes under UV
activation, which leaves a margin for improvement economically and
with regard to simplifying the means employed.
[0047] It is thus apparent that the prior art is essentially devoid
of anti-soil varnishes compatible with coatings, in particular
silicone elastomer coatings, for supports, in particular textile
supports, and even less in anti-soil varnishes which meet the above
specifications.
SUMMARY OF THE INVENTION
[0048] Novel anti-soil varnish compositions for various supports
have now been developed, optionally silicone supports, in
particular flexible supports (textiles), especially those coated
with silicone elastomers, or supports in the massive form made of
silicone elastomer, such varnish compositions having the quality of
having good resistance to soiling, of being economical, of being
fully attached to the support and in particular to the coated
elastomer layer and of introducing the desired low surface slip, as
well as a sufficiently glossy appearance.
[0049] Another aspect of the present invention is the provision of
an anti-soil varnish which can be easily applied to various types
of supports.
[0050] Another aspect of the invention is the provision of an
anti-soil varnish which can be crosslinked, which is easy to employ
and which is economical.
[0051] Another aspect of the present invention is the provision of
a varnish composition based on silyl-comprising entities compatible
with silicone elastomers and useful, in particular, in the
preparation of anti-soil varnishes, these compositions having a
reasonable price and being simple to prepare.
[0052] Another aspect of the invention is the provision of a
process for the simple and economical varnishing of various
silicone-comprising supports or silicones formed, for example, by
woven or nonwoven fibrous substrates coated with a layer of
crosslinked silicone elastomer or by supports in the massive form
at least partially composed of silicone, using anti-soil varnish
based on silyl-comprising entities compatible with the silicone
elastomers.
[0053] Another aspect of the invention is the provision of a
composite comprising a support coated with at least one layer of
elastomer and covered with a silicone varnish as defined above, for
example a cloth (architectural textile) coated with crosslinked
silicone elastomer, with high resistance to soiling substances.
[0054] Thus, to satisfy the above objectives, the present invention
first features crosslinkable silyl-comprising varnishes having, in
particular, anti-soil properties and comprising:
[0055] A. at least one alkenylsilane;
[0056] B. at least one catalytic system comprising: [0057] B/1 at
least one organometallic condensation catalyst; [0058] B/2 at least
one metal M chelate and/or one metal alkoxide of general formula
M(OJ).sub.n, wherein n=valence of M and J=linear or branched
C.sub.1-C.sub.8 alkyl, M being selected from the group consisting
of: Ti, Zr, Ge and Al;
[0059] C. at least one ultrafine filler;
[0060] D. optionally, at least one arylsilane other than A;
[0061] E. optionally, at least one other silane other than A and
than D;
[0062] F. optionally, at least one thickening agent;
[0063] G. optionally, at least one functional additive.
BRIEF DESCRIPTION OF THE DRAWING
[0064] The sole FIGURE of Drawing shows the standard used in the
soiling test for the inventive coating.
DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED
EMBODIMENTS OF THE INVENTION
[0065] The silicone varnishes according to the invention are
advantageous in that they make it possible to very greatly increase
the resistance to soiling while having a glossy appearance and a
low sliding coefficient.
[0066] The mechanical qualities and the usual properties of the
supports coated using the composition according to the invention
are not affected.
[0067] In addition, this varnish composition has a stability
sufficient for use delayed with respect to its manufacture by a
storage tank compatible with marketing criteria.
[0068] The combination of components A, B and C, and optionally D
and/or E and/or F and/or G provide exceptional results. This is
because it could not have been predicted that this combination of
carefully selected components could contribute all of the
advantageous results above indicated.
[0069] The term "alkenyl" means a substituted or unsubstituted,
unsaturated, linear or branched, hydrocarbon chain having at least
one olefinic double bond and more preferably a single double bond.
Preferably, the "alkenyl" group has from 2 to 8 carbon atoms,
better still from 2 to 6. This hydrocarbon chain optionally
comprises at least one heteroatom, such as O, N or S.
[0070] Preferred examples of "alkenyl" groups are the vinyl, allyl
and homoallyl groups, vinyl being particularly preferred.
[0071] The term "alkyl" denotes an optionally substituted (e.g., by
one or more alkyls), saturated, cyclic, linear or branched,
hydrocarbon chain preferably of 1 to 10 carbon atoms, for example
of 1 to 8 carbon atoms, better still of 1 to 4 carbon atoms.
[0072] Examples of alkyl radicals are in particular methyl, ethyl,
isopropyl, n-propyl, tert-butyl, isobutyl, n-butyl, n-pentyl,
isoamyl and 1,1-dimethylpropyl.
[0073] The "alkyl" moiety of the "alkoxy" radical is as defined
above.
[0074] The "alkyl" can be perfluorinated and the term
"perfluorinated alkyl" denotes an alkyl comprising at least one
perfluoroalkyl group, preferably having the formula:
--(CH.sub.2).sub.p--C.sub.qF.sub.2q+1
in which p represents 0, 1, 2, 3 or 4, q is an integer from 1 to 10
and C.sub.qF.sub.2q+1 is linear or branched. Preferred examples of
this radical are: --(CH.sub.2).sub.2--(CF.sub.2).sub.5--CF.sub.3
and --(CF.sub.2).sub.7--CF.sub.3.
[0075] The term "alkylene" denotes an optionally substituted (e.g.,
by one or more alkyls), saturated, cyclic, linear or branched,
divalent hydrocarbon chain preferably of 1 to 10 carbon atoms, for
example of 1 to 8 carbon atoms, better still of 1 to 4 carbon
atoms.
[0076] The expression "aryl" denotes a monocyclic or polycyclic,
and preferably monocyclic or bicyclic, aromatic hydrocarbon group
having from 6 to 18 carbon atoms. It should be understood that, in
the context of the invention, the term "polycyclic aromatic
radical" means a radical having two or more aromatic nuclei fused
(ortho-fused or ortho- and peri-fused) to one another, that is to
say having, in pairs, at least two carbons in common.
[0077] Mention may be made, as an example of "aryl", of phenyl
radicals.
[0078] In accordance with the invention, preferred alkenylsilanes A
are selected from the group of products consisting of:
[0079] 1. the monomers selected from among organoalkenylsilanes
comprising, per molecule, at least one alkenyl group, preferably
from alkoxylated organoalkenylsilanes and more preferably still
from the products of the following general formula:
##STR00002##
in which:
[0080] R.sup.10, R.sup.20 and R.sup.30 are each hydrogen or
hydrocarbon radicals which are identical or different from one
another and preferably represent hydrogen, an alkyl or a phenyl
radical optionally substituted by at least one alkyl radical,
[0081] L is an alkylene radical,
[0082] L.sub.1 is a valency bond or oxygen,
[0083] R.sup.40 and R.sup.50 are identical or different radicals
and are each an alkyl radical,
[0084] x'=0 or 1,
[0085] x=0 to 2, preferably 0 or 1 and more preferably still 0;
[0086] 2. the oligomers (or condensates) of monomer(s) 1.;
[0087] 3. the hydrolyzates obtained from monomer(s) 1.;
[0088] 4. and mixtures thereof.
[0089] According to a first preferred characteristic of the
invention, the monomers A1. are selected from the subgroup
consisting of vinyl- or allylalkoxysilanes and
(meth)acryloyloxy(alkoxy)silanes, such as vinyltrialkoxysilanes and
methacrylolyoxypropyltrialkoxy-silanes, vinyltrimethoxysilane
(VTMO) being particularly appropriate.
[0090] According to a second preferred embodiment of the invention,
the oligomers (of condensates) A2. are selected from the group
consisting of those obtained from the monomers A1. and preferably
from vinyltrimethoxysilane (VTMO) or from vinyltriethoxysilane
(VTEO).
[0091] Mention may be made, as examples of oligomers (or
condensates) A2., of oligomeric vinylsilanes of the type Of those
sold by Degussa under the registered trademark Dynasilan.RTM. 6490,
6498 or 6598 or else oligomeric methacryloyloxysilanes, such as
Dynasilan.RTM. 5821 and Dynasilan.RTM. 5823.
[0092] According to a third preferred embodiment of the invention,
the hydrolyzate A3. comprises a mixture of at least one monomer A1.
with acidic aqueous solution, the water/alkenylsilane monomer A1.
molar ratio being less than or equal to 1.5, preferably less than
or equal to 1.2, and more preferably still between 0.8 and 1.1.
[0093] In practice, the acidification of the medium comprising the
hydrolyzate A3. is such that the pH is, for example, between 2 and
4, preferably in the region of 2.5.
[0094] Advantageously, this acidic aqueous solution comprises at
least one acid preferably selected from the acids corresponding to
the group consisting of: HCl, H.sub.3PO.sub.4, CH.sub.3COOH and
their mixtures.
[0095] When it is present, the organometallic condensation catalyst
B/1 is preferably a catalytic tin compound, generally an organotin
salt, preferably introduced in the form of an aqueous emulsion. The
organotin salts which can be used are described in particular in
the text by Noll, Chemistry and Technology of Silicones, Academic
Press, (1968), page 337.
[0096] Use may also be made, as catalytic tin compound, either of
distannoxanes or of polyorganostannoxanes or of the reaction
product of a tin salt, in particular of a tin dicarboxylate, with
ethyl polysilicate, as disclosed in U.S. Pat. No. 3,862,919.
[0097] The reaction product of an alkyl silicate or of an
alkyltrialkoxysilane with dibutyltin diacetate, as disclosed in
BE-A-842,305, may also be suitable.
[0098] According to another possibility, recourse may be had to the
tin(II) salt, such as SnCl.sub.2 or stannous octoate.
[0099] The preferred tin salts are tin bischelates (EP-A-147,323
and EP-A-235,049), diorganotin dicarboxylates and in particular
dibutyl- or dioctyltin diversatates (GB-A-1-289,900), dibutyl- or
dioctyltin diacetate, dibutyl- or dioctyltin dilaurates or the
hydrolyzis products of the above-mentioned integers (e.g.,
diorgano- and polystannoxanes).
[0100] This catalyst B/1 can also be selected from among the
carboxylic acid salts and the halides of metals other than B/2,
such as, for example, lead, zinc, zirconium, titanium, iron,
barium, calcium and manganese.
[0101] Use is made of 0.01 to 3, preferably of 0.05 to 2, parts of
salt B/1 per 100 parts of the silanes of the composition.
[0102] As regards other component B/2 of the catalytic system B,
the preferred products are those in which the metal M is selected
from the following list: Ti, Zr, Ge, Li and Mn. It should be
emphasized that titanium is more particularly preferred. It can be
combined, for example, with an alkyl radical of butyl type.
[0103] The varnishes according to the invention additionally
comprise at least one ultrafine filler C. which may or may not be
siliceous.
[0104] This ultrafine filler C is selected from inorganic fillers
having a mean particle diameter .phi.me in the region of,
preferably less than or equal to, 0.5 .mu.m, advantageously less
than or equal to or in the region of 0.1 .mu.m; preferably
from:
[0105] siliceous fillers belonging to the group of silica powders
(colloidal silicas, combustion and precipitated silicas, or their
mixtures),
[0106] nanometric fillers presented as suspensions, such as, for
example, colloidal silica suspensions,
[0107] other inorganic fillers selected from the group consisting,
inter alia, of: TiO.sub.2, Al.sub.2O.sub.3 (aluminum hydrate) and
mica,
[0108] or their mixtures.
[0109] It may be advantageous to employ, in accordance with the
invention, at least one arylsilane D preferably selected from
phenylsilanes and more preferably still from the group consisting
of phenyltrialkoxysilanes, phenylalkyldialkoxysilanes and their
mixtures.
[0110] According to another advantageous alternative embodiment,
the varnish composition according to the invention comprises one or
more other silanes E other than the silanes A and D. These silanes
E, when they are functionalized, comprise, per molecule, one or
more functional groups which are identical to or different from one
another and which are selected from the group consisting of the
following functional groups: hydroxyl, amino (primary, secondary or
tertiary amine, optionally included in a ring or in isocyanurate
groups or HALS groups of the piperidine or other type), epoxy,
(meth)acrylo and ureido. Nonfunctionalized silanes are another
option.
[0111] Mention may be made, as examples of other silanes E, of
glycidoxypropyltrialkoxysilanes,
epoxycyclohexylethyltrialkoxysilanes, aminopropyltrialkoxysilanes,
aminoethylaminopropyltrialkoxysilanes, ethyl silicate,
methyltrimethoxysilane or methyltriethoxysilane.
[0112] The preferred varnish composition is of the type of those
which can be crosslinked by polycondensation and comprises:
[0113] A. 100 parts by weight of alkenylsilane;
[0114] B. 0.1 to 10 parts by weight of a catalytic system including
from 0 to 80% by weight, preferably from 5 to 60% by weight, of
organometallic condensation catalyst B/1;
[0115] C. 2 to 50 parts by weight of ultrafine filler;
[0116] D. 0 to 30 parts by weight of at least one arylsilane;
[0117] E. 0 to 30 parts by weight of at least one other silane
other than A and D;
[0118] F. 0 to 5 parts by weight of at least one thickening
agent;
[0119] G. 0 to 5 parts by weight of at least one functional
additive.
[0120] The viscosity of the noncrosslinked liquid varnish as
applied to the support is an important parameter of the invention.
Thus, the dynamic viscosity .eta. (expressed in mPas at 25.degree.
C.) of the A, B and C, optionally D and/or E and/or F and/or G,
varnish is such that: [0121] 2.ltoreq..eta..ltoreq.500 [0122]
preferably 5.ltoreq..eta..ltoreq.200 [0123] and more preferably
still 10.ltoreq..eta..ltoreq.150.
[0124] The dynamic viscosity .eta. at 25.degree. C. can be measured
via the well known trade test referred to as the Ford cup No. 4
test, which entails measuring the flow time in seconds of a given
amount of the product through a given orifice. This flow time is
converted to a kinematic viscosity in centistokes using a Ford cup
calibration curve well known to one skilled in the art and given in
particular in a technical flow commercial brochure from Byk
Gardner, p. 152, which company is a supplier of the Ford cup
measuring equipment.
[0125] Details with regard to the nature of the various
constituents of the silicone varnish composition according to the
invention include:
[0126] A1.=VTMO;
[0127] A2.=VTMO oligomers;
[0128] A3.=VTMO hydrolyzate;
[0129] B1.=tin salt (e.g., dibutyltin diacetate);
[0130] B2.=TetraButOxyTitanium (TBOT);
[0131] C.=treated or untreated pyrogenic silica;
[0132] D.=phenyltrimethoxysilane;
[0133] E.=other silane.noteq.A.noteq.D=for example, ethyl
silicate;
[0134] F.=wax(es) based on micronized polyamide.
[0135] The varnishes according to the invention can comprise
functional additives G. They can be covering products, such as, for
example, pigments/dyes (G.1), stabilizing agents (G.2), in
particular with regard to UV radiation, or diluents {solvents}
(G.3).
[0136] According to an advantageous embodiment of the invention,
the varnish is provided in the form of a single-component system
capable of rapidly crosslinking under hot conditions by
polycondensation.
[0137] In view of its ease of preparation, its low cost and its
anti-soil properties, the silicone varnishes according to the
invention are capable of having outlets in numerous fields of
application and in particular in the field of the coating:
[0138] of supports with a woven or nonwoven fibrous core optionally
comprising silicone (i.e., coated over at least one of its faces
with at least one layer of elastomer);
[0139] or else of supports composed of components in the massive
form made of silicone and/or comprising silicone.
[0140] According to another of its aspects, the invention relates
to a varnishing process, wherein the composition as defined above
is applied, as anti-soil varnish, to the silicone surface of a
support composed at least in part of silicone, preferably silicone
elastomer. It can be a support at least partially coated with at
least one layer of elastomer or a component made of silicone.
[0141] According to an alternative embodiment, this varnishing
process is carried out on a support, the surface of which comprises
at least nonsilicone (co)polymer preferably selected from the group
consisting of: polyamides, polyolefins, polyesters, their blends
and the copolymers.
[0142] Preferably, this process consists essentially:
[0143] in coating the support using the varnish composition A, B
and C, optionally D and/or E and/or F and/or G, as defined
above,
[0144] and in crosslinking the layer of varnish, optionally by
thermally activating the crosslinking.
[0145] According to an advantageous embodiment of the invention,
the varnish composition is applied to the support according to a
level of deposition of less than or equal 35 g/m.sup.2, preferably
of between 2 and 25 g/m.sup.2.
[0146] As regards use of the varnish composition according to the
invention, it can, for example, be applied to a support by any
appropriate coating or transfer means (for example, doctor blade,
coating roll, gravure printing, dynamic screen printing, brush,
spraying: gun, and the like).
[0147] The crosslinking of the varnish liquid silicone composition
applied to the support to be coated is generally activated, for
example, by heating the surface of the support thus coated to a
temperature of between 50 and 200.degree. C., taking into account,
very clearly, the maximum resistance of the support to heat.
[0148] The activation means are of the type of those known and
appropriate for this purpose, for example thermal activation or
activation by IR radiation.
[0149] Other details will be given in the examples which
follow.
[0150] The above defined varnishing process can relate either to
architectural textiles or to supports other than architectural
textiles.
[0151] The present invention also features the varnished support
(or composite), with or without the exception of the composites
intended to form architectural textiles as defined above, having
anti-soil properties and a low sliding coefficient which is capable
of being obtained by the process as described above. This composite
is characterized in that it comprises:
[0152] a support, preferably a flexible support, more preferably
still selected from the group consisting of: [0153] textiles,
[0154] nonwoven fibrous supports, [0155] polymer films, in
particular polyester, polyamide, polyolefin, polyurethane,
poly(vinyl chloride) or silicone films,
[0156] a coating integral with at least one of the faces of the
support and composed of at least one layer of silicone elastomer
and/or of at least one other (co)polymer,
[0157] at least one layer of varnish as defined above.
[0158] According to an alternative embodiment, the composite
capable of being obtained by the process described above can
comprise:
[0159] a support which is massive or block in form optionally made
of silicone and/or at least partially coated with silicone, the
silicone preferably being a silicone elastomer,
[0160] and at least one layer of varnish as defined above.
[0161] The silicone coating is optional, for example when the
support is itself silicone.
[0162] Advantageously, the support of the composite according to
the invention comprises at least one material selected from the
group consisting of:
[0163] glass, in the massive form or in the form of fibers,
[0164] ceramics, in the massive form or in the form of fibers,
[0165] natural or synthetic polymers which are provided in the
massive form, in the form of fibers or in the form of films, in
particular of polyester, polyamide, polyolefin, polyurethane,
poly(vinyl chloride) or silicone,
[0166] cellulose or lignocellulose materials in the massive or
fibrous form, in particular paper, board or the like,
[0167] and their combinations.
[0168] The flexible supports to which the invention relates can be,
inter alia, architectural textiles.
[0169] Thus, this invention also features an architectural textile,
same comprising a composite capable of being obtained by the
varnishing process described above and applied to an architectural
textile, said composite comprising:
[0170] a support, preferably a flexible support, more preferably
still selected from the group consisting of: [0171] textiles,
[0172] nonwoven fibrous supports, [0173] polymer films,
[0174] optionally a coating integral with at least one of the faces
of the support and which comprises at least one layer of silicone
elastomer and of at least one other (co)polymer,
[0175] at least one layer of varnish as defined above.
[0176] Advantageously, the support included in this architectural
textile comprises at least one material selected from the group
consisting of:
[0177] glass in the form of fibers,
[0178] ceramics in the form of fibers,
[0179] natural or synthetic polymers which are provided in the form
of fibers or in the form of films, in particular of polyester,
polyamide, polyurethane, poly(vinyl chloride) or silicone,
[0180] cellulose or lignocellulose materials in the massive or
fibrous form, in particular paper, board or the like.
[0181] Other flexible supports to which the invention relates and
which are different from the "architectural textiles" can be, inter
alia, those intended for the manufacture of:
[0182] airbags used for the protection of the occupants of a
vehicle,
[0183] glass braids (woven glass sheaths for thermal and dielectric
protection for electrical wires),
[0184] conveyor belts, fire barrier fabrics or thermal insulation
fabrics,
[0185] clothes,
[0186] compensators (flexible sealing sleeves for pipe work), and
the like.
[0187] According to another of its aspects, the present invention
features:
[0188] manufactured articles comprising the composite as defined
above which are different from those included in the composition of
architectural textiles,
[0189] and manufactured articles comprising architectural textiles
based on the composite also defined above.
[0190] The fibrous supports intended to be coated and then
varnished in accordance with the invention can, for example, be
woven fabrics, nonwoven fabrics or knitted fabrics or more
generally any fibrous support comprising fibers selected from the
group of materials consisting of: glass, silica, metals, ceramics,
silicon carbide, carbon, boron, natural fibers, such as cotton,
wool, hemp or flax, artificial fibers, such as viscose, or
cellulose fibers, synthetic fibers, such as polyesters, polyamides,
polyacrylics, chlorofibers, polyolefins, synthetic rubbers,
poly(vinyl alcohol), aramids, fluorofibers, phenolics, silicones,
and the like.
[0191] Mention may be made, as preferred examples of fibrous
supports, of glass, polyester, polyamide, polyurethane, polyolefin,
poly(vinyl chloride) or silicone fabrics or else paper, board or
the like.
[0192] In addition to textile flexible supports coated with
silicone, the anti-soil varnish according to the invention can be
applied to plastic films (for example, protective packaging films),
e.g., made of polyester, polyurethane, polyamide, polyolefin
(polyethylene, polypropylene), poly(vinyl chloride) or
silicone.
[0193] The present invention furthermore also features the use of a
composition as defined above as anti-soil varnish on a silicone or
nonsilicone surface, preferably on a silicone surface, for example
for coating a fibrous support, with or without the exception of any
architectural textile.
[0194] The supports which are massive or block in form to which the
invention relates can, inter alia, be components selected from the
group consisting of:
[0195] furniture,
[0196] cladding,
[0197] advertising displays,
[0198] windbreaks,
[0199] compensators (flexible sealing sleeves for pipework),
[0200] or filter panels.
[0201] Finally, the present invention features any manufactured
article comprising the composite as defined above.
[0202] The silicone capable of forming the coating or the component
which is massive in form to which the varnish composition according
to the invention is capable of being applied can be an elastomer
based on polyorganosiloxane(s) which can be crosslinked or which is
at least partially crosslinked and which is preferably selected
from:
[0203] polyaddition or polycondensation, RTV silicones,
[0204] and/or peroxide-cured or polyaddition HCE silicones,
[0205] and/or polyaddition LSR silicones.
[0206] The anti-soil varnish obtained from the composition as
defined above is applied to the upper layer(s) of silicone
elastomer.
[0207] The expressions "RTV", "LSR" and "HCE" are well known to one
skilled in the art: RTV is the abbreviation for "Room Temperature
Vulcanizing", LSR is the abbreviation for "Liquid Silicone Rubber"
and HCE is the abbreviation for "Heat Curable Elastomer".
[0208] In practice, the invention more specifically features
supports (for example textiles, such as those used for the
manufacture of airbags), coated on one and/or other of their faces
with a layer of RTV, HCE or LSR crosslinked silicone elastomer,
itself coated with an anti-soil silicone varnish coating as defined
above.
[0209] The problem of the introduction of anti-soil properties is
particularly acute regarding these crosslinked silicone elastomer
coatings since, as has already been indicated above, the latter
have the characteristic of having a tacky feel.
[0210] The polyorganosiloxanes which are the main constituents of
the tacky layers of crosslinked elastomers or of the
supports/components which are massive in form on which the varnish
according to the invention is capable of being applied can be
linear, branched or crosslinked and can comprise hydrocarbon
radicals and/or reactive groups, such as, for example, hydroxyl
groups, hydrolyzable groups, alkenyl groups and hydrogen atoms. It
should be noted that polyorganosiloxane compositions are fully
described in the literature and in particular in the test by Walter
Noll: Chemistry and Technology of Silicones, Academic Press, 1968,
2nd edition, pages 386 to 409.
[0211] More specifically, these polyorganosiloxanes which can be
varnished are comprised of siloxyl units of general formula:
R n 1 .smallcircle. SiO 4 - n 1 2 ( I ' ) ##EQU00001##
and/or of siloxyl units of formula:
Z x 1 .smallcircle. R y 1 .smallcircle. SiO 4 - x 1 - y 1 2 ( II '
) ##EQU00002##
in which formulae the various symbols have the following
meanings:
[0212] the R.degree. symbols, which are identical or different,
each represent a group of nonhydrolyzable hydrocarbon nature, it
being possible for this radical to be:
[0213] an alkyl or haloalkyl radical having from 1 to 5 carbon
atoms and comprising from 1 to 6 chlorine and/or fluorine
atoms,
[0214] cycloalkyl and halocycloalkyl radicals having from 3 to 8
carbon atoms and comprising from 1 to 4 chlorine and/or fluorine
atoms,
[0215] aryl, alkylaryl and haloaryl radicals having from 6 to 8
carbon atoms and comprising from 1 to 4 chlorine and/or fluorine
atoms,
[0216] cyanoalkyl radicals having from 3 to 4 carbon atoms;
[0217] the Z.degree. symbols, which are identical or different,
each represent a hydrogen atom, a C.sub.2-C.sub.6 alkenyl group, a
hydroxyl group, a hydrolyzable atom or a hydrolyzable group;
[0218] n.sub.1=an integer equal to 0, 1, 2 or 3;
[0219] x.sub.1=an integer equal to 0, 1, 2 or 3;
[0220] y.sub.1=an integer equal to 0, 1 or 2;
[0221] the sum x+y is between 1 and 3.
[0222] Mention may be made, by way of illustration, among the
R.degree. organic radicals directly bonded to the silicon atoms, of
the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-pentyl,
t-butyl, chloromethyl, dichloromethyl, .alpha.-chloroethyl,
.alpha.,.beta.-dichloroethyl, fluoromethyl, difluoromethyl,
.alpha.,.beta.-difluoroethyl, 3,3,3-trifluoropropyl,
trifluorocyclopropyl, 4,4,4-trifluorobutyl,
3,3,4,4,5,5-hexafluoropentyl, .beta.-cyanoethyl,
.gamma.-cyanopropyl, phenyl, p-chlorophenyl, m-chlorophenyl,
3,5-dichlorophenyl, trichlorophenyl, tetrachlorophenyl, o-, p- or
m-tolyl, .alpha.,.alpha.,.alpha.-trifluorotolyl or xylyl, such as
2,3-dimethylphenyl or 3,4-dimethylphenyl, groups.
[0223] The R.degree. organic radicals bonded to the silicon atoms
are preferably methyl or phenyl radicals, it being possible for
these radicals optionally to be halogenated, or else cyanoalkyl
radicals.
[0224] The Z.degree. symbols can be hydrogen atoms, hydrolyzable
atoms, such as halogen atoms, in particular chlorine atoms, vinyl
groups, hydroxyl groups or hydrolyzable groups, such as, for
example, amino, amido, aminoxy, oxime, alkoxy, alkenyloxy or
acyloxy.
[0225] The nature of the polyorganosiloxane and thus the ratios of
the siloxyl unit (I') and (II') to one another and the distribution
of the latter is, as is known, selected according to the
crosslinking treatment which will be carried out on the curable (or
vulcanizable) composition for the purpose of converting it to
elastomer.
[0226] It is possible to use a great variety of single-component or
two-component compositions which crosslink by polyaddition or
polycondensation reactions in the presence of a metal catalyst and
optionally of an amine and of a crosslinking agent.
[0227] Two-component or single-component polyorganosiloxane
compositions which crosslink at ambient temperature (RTV) or under
hot conditions (HCE) by polyaddition reactions, essentially by
reaction of hydrosilyl groups with alkenylsilyl groups, in the
presence of a metal catalyst, preferably a platinum catalyst, are
disclosed, for example, in U.S. Pat. Nos. 3,220,972, 3,284,406,
3,436,366, 3,697,473 and 4,340,709. The polyorganosiloxanes
participating in these compositions are generally composed of pairs
based, on the one hand, on a linear, branched or crosslinked
polysiloxane composed of (II') units in which the Z.degree. residue
represents a C.sub.2-C.sub.6 alkenyl group and where x.sub.1 is at
least equal to 1, optionally in combination with (I') units, and,
on the other hand, on a linear, branched or crosslinked
hydropolysiloxane composed of (II') units in which the Z.degree.
residue then represents a hydrogen atom and where x.sub.1 is at
least equal to 1, optionally in combination with (I') units.
[0228] Two-component or single-component polyorganosiloxane
compositions which crosslink at ambient temperature (RTV) by
polycondensation reactions under the effect of moisture, generally
in the presence of a metal catalyst, for example a tin compound,
are disclosed, for example for single-component compositions, in
U.S. Pat. Nos. 3,065,194, 3,542,901, 3,779,986 and 4,417,042 and in
FR-A-2,638,752 and, for two-component compositions, in U.S. Pat.
Nos. 3,678,002, 3,888,815, 3,933,729 and 4,064,096. The
polyorganosiloxanes included in these compositions are generally
linear, branched or crosslinked polysiloxanes comprising (II')
units in which the Z.degree. residue is a hydroxyl group or a
hydrolyzable atom or group and where x.sub.1 is at least equal to
1, with the possibility of having at least one Z.degree. residue
which is equal to a hydroxyl group or to a hydrolyzable atom or
group and at least one Z.degree. residue which is equal to an
alkenyl group when x.sub.1 is equal to 2 or 3, said (II') units
optionally being used in combination with (I') units. Such
compositions can additionally comprise a crosslinking agent which
is in particular a silane carrying at least three hydrolyzable
groups, such as, for example, a silicate, an alkyltrialkoxysilane
or an aminoalkyltrialkoxysilane.
[0229] These RTV organopolysiloxane compositions which crosslink by
polyaddition or polycondensation reactions advantageously have a
viscosity at 25.degree. C. at most equal to 100,000 mPas and
preferably of between 5,000 and 50,000 mPas.
[0230] It is possible to employ RTV compositions which crosslink at
ambient temperature by polyaddition or polycondensation reactions
having a viscosity at 25.degree. C. of greater than 100,000 mPas,
such as that within the range from a value of greater than 100,000
mPas to 300,000 mPas; this form is recommended when it is desired
to prepare filler-comprising curable compositions in which the
filler(s) used has(have) a tendency to separate by
sedimentation.
[0231] It is also possible to employ compositions which crosslink
under hot conditions by polyaddition reactions and more
specifically polyaddition compositions said to be of HCE type
having a viscosity at 25.degree. C. at least equal to 500,000 mPas
and preferably of between 1 million mPas and 10 million mPas and
even more.
[0232] The compositions can also be compositions which can be cured
at high temperature under the action of organic peroxides, such as
2,4-dichlorobenzoyl peroxide, benzoyl peroxide, t-butyl
perbenzoate, cumyl peroxide or di(t-butyl) peroxide. The
polyorganosiloxane or gum included in such compositions (referred
to simply as of HCE type) is then composed essentially of (I')
siloxyl units, optionally in combination with (II') units in which
the Z.degree. residue represents a C.sub.2-C.sub.6 alkenyl group
and where x.sub.1 is equal to 1. Such HCEs are disclosed, for
example, in U.S. Pat. Nos. 3,142,655, 3,821,140, 3,836,489 and
3,839,266. These compositions advantageously have a viscosity at
25.degree. C. at least equal to 1 million mPas and preferably of
between 2 million and 10 million mPas and even more.
[0233] Other polyorganosiloxane compositions which can be varnished
by the silicone varnish composition according to the invention are
those, single-component or two-component, which crosslink under hot
conditions by polyaddition reactions, referred to as LSR
compositions. These compositions correspond to the definitions
given above with respect to the preferred compositions referred to
as RTV compositions, except as regards the viscosity, which this
time is within the range from a value of greater than 100,000 mPas
to more than 500,000 mPas.
[0234] Without this being limiting, the silicone elastomer coatings
on which the anti-soil varnish according to the invention can be
applied are more especially coatings obtained from room temperature
vulcanizable, RTV silicone elastomer compositions, in particular of
two-component type (RTV 2), by polyaddition.
[0235] In order to further illustrate the present invention and the
advantages thereof, the following specific examples are given, it
being understood that same are intended only as illustrative and in
nowise limitative. In said examples to follow, all parts and
percentages are given by weight, unless otherwise indicated.
EXAMPLES
[0236] Tests:
[0237] Resistance to Soiling:
[0238] Soiling Test:
[0239] Carbon black is deposited on the varnish coating and the
ability of the support to be more or less easily cleaned is
recorded on a scale of 0 to 5 (cf. single appended FIGURE): [0240]
0=remains black; 5=a few black marks remain
[0241] As good wetting is the necessary condition for uniform
coating by the varnish, this covering is assessed by an evaluation
of the resistance to soiling which it introduces.
[0242] The resistance is the resistance to the deposition of a
carbon black soiling substance; the reference chart shown in the
single appended FIGURE serves for the grading. This FIGURE gives
the scale of resistance to soiling: classification from 0 to 5,
from the most to the least soiling.
[0243] Visual Appearance:
[0244] It is recorded whether the varnish confers a glossy or matt
appearance.
[0245] Support:
[0246] 1. The support sample is an RTV II coating applied to a
polyester fabric.
[0247] This RTV II coating is prepared as follows:
[0248] 40 kg of an .alpha.,.omega.-divinylated silicone oil with a
viscosity of 1.5 Pas, which assays 0.1 meq of vinyl (Vi) per gram
of oil, 0.24 kg of drinking water and 0.24 kg of
hexamethyldisilazane are introduced into a 100 l arm mixer. After
homogenizing, 13.9 kg of a combustion silica characterized by a
specific surface of 200 m.sup.2/g are added portionwise over
approximately 2 hours. After mixing for approximately 1 hour, 2.27
kg of hexamethyldisilazane are added over approximately 1 hour. 2
hours later, a heating phase is begun, during which the mixture is
placed under a stream of nitrogen (30 m.sup.3/h); the heating
continues until approximately 140.degree. C. is reached, which
stationary temperature is maintained for 2 hours in order to remove
the volatile materials from the composition. The suspension is then
allowed to cool.
[0249] Starting from this suspension, a part A and a part B are
formulated in appropriate reactors.
[0250] The Part A Comprises:
[0251] 320 g of the suspension,
[0252] 111 g of an .alpha.,.omega.-divinylated oil with a viscosity
of 100 Pas which assays 0.03 meq Vi per gram of oil,
[0253] 35 g of ground quartz with a mean particle size (d50) of
approximately 2.5 .mu.m,
[0254] 12 g of a polyhydro oil with a viscosity of 0.3 Pas which
assays 1.6 meq SiH per gram of oil,
[0255] 12 g of an .alpha.,.omega.-dihydro oil which assays 1.9 meq
SiH per gram of oil,
[0256] 5 g of y-methacryloyloxypropyltrimethoxysilane,
[0257] 5 g of y-glycidoxypropyltrimethoxysilane,
[0258] 0.7 g of ethynylcyclohexanol.
[0259] The Part B Comprises:
[0260] 480 g of the suspension,
[0261] 20 g of butyl orthotitanate,
[0262] 1.1 g of a Karstedt catalyst quantitatively determined at
10% of platinum.
[0263] The parts A and B are mixed in the ratio of 100 to 10 and,
after removal of bubbles, the test specimens necessary for the
measurement of the mechanical properties and of the adhesion
properties are prepared.
[0264] The crosslinking on the support under consideration is
carried out by leaving for 10 minutes in a ventilated oven
maintained at 150.degree. C.
[0265] The thickness of the coating is sufficient (approximately
300 .mu.m) for the coated surface to be smooth and for the nature
of the fabric used to become completely concealed.
[0266] 2. The varnish is deposited using a Meyer rod; under these
conditions, the amount deposited is of the order of 15-20
g/m.sup.2. The combined product is subsequently introduced into an
oven to bring about the drying and the crosslinking of the
varnish.
Example 1
[0267] The following compositions are prepared:
[0268] Alkenylsilane A.1: Vinyltrimethoxysilane (VTMO),
[0269] Alkenylsilane A.2: Dynasilan.RTM. 6490 is a
vinyltrimethoxysilane (VTMO) condensate sold by Degussa,
[0270] Component B.1 of the catalytic system: DBTDA; dibutyltin
diacetate,
[0271] Component B.2 of the catalytic system: TBOT; butyl
titanate,
[0272] Ultrafine filler C: R812 is a treated pyrogenic silica sold
by Degussa.
TABLE-US-00001 TABLE 1 Reference 1-1 1-2 1-3 A.1--VTMO 100 --
A.2--Dynasilan .RTM. 6490 -- 100 100 B.1--DBTDA 2 2 2 B.2--TBOT 2 2
2 C--Silica R812 2
[0273] The properties evaluated are combined in Table 2 below.
[0274] It shows:
[0275] the advantage of the condensed silane in terms of gloss,
[0276] the reduced reactivity of this silane,
[0277] the necessary presence of silica in order to provide the
wetting of the silicone support,
[0278] the good resistance to soiling in the case of the varnish
1-3.
TABLE-US-00002 TABLE 2 1-1 1-2 1-3 Wetting Inadequate Inadequate
Correct Time for 1 min 120.degree. C. 3 min 120.degree. C. 3 min
120.degree. C. crosslinking Appearance Matt Glossy Glossy
Resistance to 1 1 3 soiling
Example 2
[0279] The following compositions are prepared in a stirred
laboratory reactor with a capacity of 500 cm.sup.3 operating at
ambient temperature and under enclosed conditions:
[0280] Alkenylsilane A.1: Vinyltrimethoxysilane (VTMO),
[0281] Alkenylsilane A.2: Dynasilan.RTM. 6490 is a
vinyltrimethoxysilane (VTMO) condensate sold by Degussa,
[0282] Alkenylsilane A.3: hydrolyzate of A.1=A.1+acid,
[0283] Component B.1 of the catalytic system: DBTDA; dibutyltin
diacetate,
[0284] Component B.2 of the catalytic system: TBOT; butyl
titanate,
[0285] Ultrafine filler C: R812 is a treated pyrogenic silica sold
by Degussa, Arylsilane D,
[0286] Thickening agent F: micronized polyamide C Super.RTM. is the
CrayVallac.RTM. Super distributed by Cray Valley.
TABLE-US-00003 TABLE 3 Reference 2 A.1--VTMO 27.34 A.2--Dynasilan
.RTM. 6490 2.66 A.3--Hydrochloric acid, 10.sup.-2 M 10 B.2--TBOT 60
B.1--Dibutyltin diacetate 2 C--Silica, R 812 0.2
D--Phenyltrimethoxysilane 1.75 F--Thickening agent, C Super 1
[0287] The hydrolysis of the VTMO A.1 is first carried out by
contact with the acid with stirring.
[0288] At the same time, the silica C and the thickening agent F C
Super, are energetically dispersed in the alkenylsilane A.2,
Dynasilan 6490.
[0289] The mixture is subsequently brought to completion.
[0290] As in example 1, the varnish 2 is deposited on the RTV II
silicone coating.
[0291] The wetting of the support is good.
[0292] The viscosity measured is 15 mPas under a gradient of 100
s.sup.-1.
[0293] The crosslinking is effective in 1 minute at 120.degree.
C.
[0294] The film produced has a glossy to satiny appearance.
[0295] The resistance to soiling lies between 3 and 4.
[0296] Each patent, patent application, publication and literature
article/report cited or indicated herein is hereby expressly
incorporated by reference.
[0297] While the invention has been described in terms of various
specific and preferred embodiments, the skilled artisan will
appreciate that various modifications, substitutions, omissions,
and changes may be made without departing from the spirit thereof.
Accordingly, it is intended that the scope of the present invention
be limited solely by the scope of the following claims, including
equivalents thereof.
* * * * *