Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/541—Silicon-containing compounds containing oxygen
  • C08K5/5415—Silicon-containing compounds containing oxygen containing at least one Si—O bond
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
  • D21H19/24—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/32—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming a linkage containing silicon in the main chain of the macromolecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
  • C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/04—Polysiloxanes
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/59—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon

Definitions

• the invention relates to the general field of silicone coating on high speed cylinders of various flexible substrates, such as sheets of paper or of synthetic polymer (polyolefin, polyester, etc.), or else of textile.
• the invention relates to the coating of flexible materials with liquid compositions containing one or more polyorganosiloxanes crosslinkable by polyaddition, dehydrogenation, polycondensation, cationic or free radical to form a film or protective coating having in particular anti-adhesion and / or hydrophobic properties.
• Flexible media can be paper, cardboard, plastic film, or metal film.
• the applications of these silicone-coated substrates are for example: food paper (baking molds, packaging), label / adhesive tape, seal, etc.
• These flexible supports with crosslinkable liquid silicones is carried out on coating devices operating continuously, and at a very high speed.
• These devices comprise coating heads consisting of several cylinders including a pressure roll and a coating roll, which is fed continuously in crosslinkable liquid silicone composition, by means of a series of rollers contiguous to each other.
• the flexible support strip travels at a high speed between the pressure roll and the coating roll to be coated on at least one of its faces with a silicone film intended to crosslink by means of crosslinking means arranged downstream of the roll head. coating.
• These crosslinking means may be emitters of heat, radiation (e.g. ultraviolet) or electron beams for example.
• This phenomenon results first of all in a loss of consumable, and especially a deposit of droplets of coating liquid on the support downstream (for example at the oven), which seriously affects the quality of the coating.
• the "misting" causes rapid fouling of the roll coating device, resulting in maintenance constraints and premature wear.
• this fog generally has around the coating head, a suction system for capturing said fog.
• Another approach to combat the formation of fog in roll coating machines is to act on the formulation of the liquid silicone coating composition.
• the process for the preparation of these star-shaped silicone polymers consists in reacting (by hydrosilylation) incompletely a polyorganosiloxane comprising ⁇ SiH reactive units with a long-chain olefin in order to obtain a partially substituted polyhydrogenoorganosiloxane which is then reacted with hydrosilylation with an MQ-type vinyl silicone resin and a long-chain diolefin. It is clear that such compositions are relatively complex and therefore expensive to obtain. Moreover, they are still perfectible with regard to the fight against the formation of fog in silicone coating on rolls, at high speed.
• European Patent EP-0 716 115 discloses a method of manufacturing a high speed silicone coating composition with rolls, this composition being presented as allowing the reduction of the fog density. According to this process, a trimethylsilyl-terminated polydimethylmethylhydroxyl-methylsiloxane with a degree of polymerization of 12 is used, as well as 0.01% of a polydimethylsiloxane substituted with perfluoroethylbutyl and methylvinyl functions, the ends of which are of the dimethylvinylsiloxyl type. and of degree of polymerization equal to 300, as well as polypropylene glycol and optionally a stearic or oleic alcohol.
• polydimethylsiloxanes functionalized with polyoxypropylene groups are combined with other functionalized polydimethylsiloxanes, e.g., with hexene units as well as with a platinum-based hydrosilylation catalyst, to form silicone coating compositions to reduce fogging.
• the functionalization units may be hydrophobic residues such as residues of stearic or oleic acid.
• US Pat. No. 4,808,391 relates to inks and varnishes based on silicone, and more specifically to a process for applying these inks / varnishes to a substrate, using a roller coating machine operating at a high speed. speed.
• This patent notably discloses compositions comprising polydimethylsiloxanes with vinyl ends with a viscosity at 25 ° C. of between 15,000 and 50,000 mPa.s.
• These liquid coating compositions also comprise a platinum-based catalyst and a rheological additive consisting of silica with a high specific surface area, in particular combustion silica.
• US Pat. No. 6,057,033 discloses silicone compositions intended to be coated on flexible substrates to form, after cationic cross-linking under UV, with a non-stick coating.
• these compositions comprise cellulose fibers having an average length of between 15 and 100 ⁇ m and an average thickness of between 5 and 40 ⁇ m.
• the polyorganosiloxanes used are polyorganosiloxanes functionalized with crosslinking groups of the acryloxy or methacryloxy type, allowing radical cross-linking under UV.
• the cellulose fibers incorporated in the composition make it possible to provide a solution to the technical problem which is to obtain a non-brittle cross-linked non-stick silicone coating.
• the cellulose fibers are presented as providing improvements in the transfer of the silicone coating film to the substrate, the cutting resistance, the mechanical properties (tensile and tear resistance), the fastening of the coating on paper, the reduction of the absorption of the coating liquid within the paper, and incidentally the reduction of the formation of fog.
• Japanese patent application JP-62 64 011 which describes a coating liquid containing a film-forming resin and a solvent, and which also contains wax particles with a diameter of between 1 and 10 ⁇ m, the diameter of the particle, is also mentioned for the record. the largest being at most equal to 150% of the thickness of the wet coating film applied to the support.
• Such a coating liquid would allow an increase in coating speed of at least 10 to 30 m / min, a priori through a limitation of fogging. The teaching of such a document is to be rejected because it does not concern silicone coatings.
• one of the essential objectives of the invention is to propose an effective method of combating the appearance of fog when coating flexible substrates with a liquid silicone precursor composition of crosslinked coatings, this coating is performed using a cylinder coating device operating at high speed.
• Another essential objective of the invention is to propose an economical and simple method of combating the appearance of fog when coating flexible substrates with a silicone composition intended to crosslink, this coating being carried out in a device for cylinder coating operating at high speed.
• Another essential object of the invention is to provide a novel additive which makes it possible to reduce the formation of fog during high-speed coating on rolls, of flexible materials, by means of silicone compositions which can be crosslinked in non-stick coatings.
• Another essential objective of the invention is to propose a method for combating the appearance of fog in the context of the coating of flexible supports, with a silicone composition crosslinkable in anti-adherent coatings, using a roll coating device. All these objectives, among others, are achieved by the present invention which firstly relates to a method of combating the appearance of misting ("misting") during the coating of flexible supports comprising the following steps: ) preparing a silicone precursor silicone coating composition (s) comprising:
• At least one catalyst or photoinitiator C the nature of which is chosen according to the type of reaction envisaged for said polyorganosiloxane A,
• step a) adding to said silicone composition liquid X an anti-mist additive E ("antimisting" additive) having the following characteristics:
• At least one organosiloxane monomer, oligomer and / or polymer F having, per molecule, at least one reactive unit ⁇ SiH; with - at least one monomer, oligomer and / or organosiloxane polymer G having, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a C 40 carbinol radical, in the presence:
• this property of the anti-fog additive E according to the invention is due to the choice of this ratio and to the nature of the reaction involved (reaction of dehydrogeno- condensation) which make it possible to obtain branched polymers having viscoelastic properties that are useful for combating the appearance of fog in a high-speed cylinder coating system.
• the rheological behavior of the anti-mist additive E according to the invention can also be illustrated by the value of its elastic modulus (G ') and viscous (G ") .
• the anti-fog additive E according to the invention ) is in a liquid form, possibly following dilution with a diluent J 'or a solvent J ", and b) the tangent of the loss angle ⁇ (tan ⁇ ) of said anti-fog additive E, which is the ratio of the viscous modulus (G ") on the elastic modulus (G '), is> 1.
• the anti-fog additive E according to the invention is used in amounts sufficient to reduce the amount of misting during the coating.
• it can implement the additive according to the invention in amounts of between 0.1 to 15 parts by weight relative to the total weight of the liquid silicone composition X precursor coating (s) silicone.
• dehydrogeno-condensation is meant a reaction between ⁇ SiH units and on the other hand ⁇ SiOH units which leads to the formation of ⁇ Si-O-Si ⁇ bonds and the release of hydrogen gas. This reaction is catalyzed by an effective amount of a dehydrogenation condensation catalyst H.
• the term "effective amount” means the quantity that is sufficient to initiate the reaction. This quantity must be as small as possible in order to allow a better conservation in time of the composition.
• Useful catalyst concentrations are from about 1 to about 6 , preferably from about 1 to about 6, and from about 1 to about 10 parts by weight of the organosiloxane polymer solids to be reacted.
• Any catalyst capable of initiating a dehydrogen-condensation reaction may be suitable.
• rhodium complex (RhCI 3 [(C 8 H 1 y) 2 S] 3 ) cited in US Pat. No. 4,262,107, a platinum complex such as the Karstedt catalyst, catalysts platinum, rhodium, palladium, tin or iridium.
• iridium-based catalyst As iridium-based catalyst, mention may be made of the following compounds: Ir (CO) (TPP) 2 , Ir (CO) 2 (acac), H (Cl) 2 (TPP) 3 , and Cl (Cyclooctene) 2 ] 2 Ir 1 (CO) (TPP) 2 and Ir H (CO) (TPP) 3 formulas in which TPP signifies a triphenylphosphine group and acac an acetylacetonate group. You can also use catalysts such as dibutyltindilaurate or those cited in the book by Noll "Chemistry and Technology of Silicones", pages 205 and 307, Academic Press, 1968-2 nd Edition).
• FR-A-2 806 930 discloses in particular a chloroplatinic acid-based catalyst. (H 2 PtCl 6 , 6H 2 O)
• the crosslinking inhibitor D is generally used to give the ready-to-use composition a certain shelf life ("pot-life").
• pot-life By playing on the one hand on the nature of the catalytic set and y ⁇ . - its concentration in the composition (from which it derives a given crosslinking rate) and on the other hand on the nature of the retarder and ⁇ > h concentration, it is possible to adjust the length of pot life.
• the activity of the catalytic unit is restored by heating (thermoactivation).
• the retarder is preferably chosen from acetylenic alcohols (ethynylcyclohexanol: ECH) and / or diallylmaleates and / or triallylisocyanurates and / or dialkylmaleates (diethylmaleates and / or dialkylalcinyledicarboxylates) (diethylacetylene dicarboxylate) or else from polyorganosiloxanes. preferably cyclic and substituted by at least one alkenyl, with 1-tetramethylvinyltetrasiloxane being particularly preferred, or alkylated maleates.
• Acetylenic alcohols are useful retarders according to the invention.
• Examples include: ethynyl-1-cyclohexanol 1;
• phosphinic derivatives include for example tris (2,4-di-tert-butylphenyl) phosphite (marketed by CIBA under the lrgafos-168 ® reference) or those described in the international patent application WO2004 / 061003 and in particular the compound Irgafos ® P-EPQ of formula:
• Such a retarder is in particular present at 1 -100 molar equivalent / metal of the catalytic system.
• crosslinking inhibitors I and I 'contemplated for the process according to the invention are, for example, those described for inhibitor D.
• it is tris- (2,4-di-tert-butylphenyl) phosphite (marketed by CIBA under the reference Irgafos- 168 ®).
• silicone silicone precursor composition silicone coating (s) it may be advantageous to implement at least one adhesion modulator system K, to allow control of the anti-adhesion properties of the crosslinked silicone coating.
• EP-A-0 601 938 can be cited, the content of which is fully included in the present invention. present statement.
• the adhesion modulator system K is:
• a radiation-crosslinking formulation a polyorganosiloxane resin of formula MD'Q or MM'Q.
• J 'and J "mention may be made of aliphatic solvents, aromatic solvents, chlorinated solvents, eg: white spirit, ketones such as methyl ethyl ketone and acetone, alcohols such as isopropanol and n-butyl alcohol, saturated, unsaturated or aromatic hydrocarbons, advantageously pentane, hexane, heptane, octane, toluene, xylene , benzene, petroleum cuts "naphthas"; C 7 -C 8 petroleum cuts, halogenated hydrocarbons and mixtures thereof.
• polyorganosiloxanes A of the silicone precursor silicone liquid composition silicone they may be of the type which crosslink at room temperature or with heat by polyaddition reactions in the presence of a metal catalyst in this case. platinum-based.
• RTV Room Temperature Vulcanizing
• EVC polyorganosiloxane polyaddition compositions
• a metal catalyst preferably platinum
• the polyorganosiloxanes A may also be of the type which crosslink at room temperature by moisture-based polycondensation reactions, in the presence generally of a metal catalyst, for example a tin compound (RTV polycondensation).
• a metal catalyst for example a tin compound (RTV polycondensation).
• RTV polycondensation a metal catalyst
• the compositions employing this type of polyorganosiloxane are described, for example, in US Pat. Nos. 3,065,194, 3,542,901, 3,779,986, 4,417,042 and in patent FR-2,638,752 (monocomponent compositions) and in US Pat. US-3,678,002, 3,888,815, 3,933,729 and 4,064,096 (two-component compositions).
• the polyorganosiloxanes A entering these RTV polycondensation compositions are linear branched or crosslinked polysiloxanes bearing hydroxyl groups or hydrolyzable groups, for example alkoxy.
• Such compositions may further contain a crosslinking agent, which is, in particular, a compound bearing at least 3 hydrolyzable groups such as, for example, a silicate, an alkyltrialkoxysilane or an aminoalkyl trialkoxysilane.
• the liquid silicone composition X may also comprise one or more cationic or radical crosslinkable polyorganosiloxanes A:
• cationic initiator systems thermal initiators and / or photoinitiators
• initiators of the onium borate or organometallic complexes type proton-donating organic solvents (isopropyl alcohol, benzyl alcohol). .)
• proton-donating organic solvents isopropyl alcohol, benzyl alcohol. .
• a radical initiator via activation by actinic radiation (UV) or by electron beams.
• UV actinic radiation
• polyorganosiloxanes are for example epoxysilicones and / or vinyl ethersilicones, linear or cyclic.
• the epoxy functional polyorganosiloxanes can be prepared by hydrosilylation reactions between ⁇ SiH-type oils and epoxy-functional compounds such as vinyl-4-cyclohexenone or allyl-glycidyl ether.
• the vinyloxyfunctional polyorganosiloxanes may be prepared by hydrosilylation reaction between SiH-patterned oils and vinyloxy-functional compounds such as allylvinylether or allyl-vinyloxyethoxybenzene.
• the silicone precursor silicone precursor composition silicone to which the anti-mist additive E ("antimisting") is added comprises: at least one polyaddition-crosslinkable polyorganosiloxane A ,
• the polyorganosiloxane A is of the type of those cross-linking by polyaddition and which has siloxyl units of formula (III) with possibly at least a part of the other units being siloxyl units of average formula (IV):
• W is an alkenyl group, preferably vinyl or allyl
• the symbols Z identical or different, represent: a linear or branched alkyl radical containing 1 to 20 carbon atoms, optionally substituted by at least one halogen, preferably fluorine; the alkyl radicals being preferably methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl,
• polyaddition-crosslinkable polyorganosiloxanes A are dimethylvinylsilyl-terminated dimethylpolysiloxanes, trimethylsilyl-terminated methylvinyldimethylpolysiloxane copolymers, and dimethylvinylsilyl-terminated methylvinyldimethylpolysiloxane copolymers.
• the crosslinking organosilicon compound B is preferably of the type having units of formula (V) with possibly at least a part of the other units being units of average formula (VI): HL c Si 0 (3 -c) / 2 (V)
• alkyl radical containing 1 to 20 carbon atoms, optionally substituted by at least one halogen, preferably fluorine, the alkyl radicals preferably being methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl,
• crosslinking organosilicon compound B examples are, for example:
• dimethylpolysiloxane polymers with hydrogenodimethylsilyl ends the poly (dimethylsiloxane) (methylhydrogenosiloxy) ⁇ , ⁇ -dimethylhydrogensiloxane polymers,
• MDD ' dimethyl-hydrogenomethylpolysiloxane (dimethyl) -type copolymers with trimethylsilyl ends
• - M 1 DD ' copolymers with dimethyl-hydrogenomethylpolysiloxane units with hydrogenodimethylsilyl ends
• the polyaddition catalyst C1 is for example composed of at least one metal belonging to the platinum group.
• This catalyst may especially be chosen from platinum and rhodium compounds.
• platinum complexes and an organic product described in US-A-3 159 601, US-A-3 159 602, US-A-3,220,972 and European patents can be used.
• the most preferred catalyst is platinum.
• the amount by weight of the polyaddition catalyst C1 calculated by weight of platinum-metal, is generally between 2 and 400 ppm.
• liquid silicone composition X precursor silicone coating (s) may also contain at least one additive common in silicone compositions crosslinking by polyaddition, polycondensation, cationic or free radical.
• additives common in silicone compositions crosslinking by polyaddition, polycondensation, cationic or free radical.
• pigments for example, pigments, ...
• the anti-fog additive E (additive “antimisting") has the following characteristics:
• At least one monomer, oligomer and / or organosiloxane polymer G having, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a C 40 carbinol radical, in the presence:
• a dehydrogenation-condensation catalyst H preferably a platinum-based metal catalyst
• the nature and the amounts of the components F and G are determined so that: a) the ratio: [number of reactive unit ⁇ SiOH]: [number of reactive unit ⁇ SiH] ⁇ 1: 1, preferably ⁇ 1: 2 or even more preferably between 1: 3 and 1:50 and even more preferentially understood between 1: 3 and 1:15, and
• the anti-fog additive E is a branched polymer or a mixture comprising at least one branched polymer comprising, per molecule, at least one reactive unit ⁇ SiH. It is very advantageous to prepare the additive with a ratio: [number of reactive units
• dehydrogenation-condensation catalyst H makes it possible to improve the antimisting performance of the additive thus obtained.
• the particularly advantageous anti-fog additive E obtained according to the preparation method described above has the following mean formula:
• c and d are numbers> to 0, - b> 0, - 0.5 mole%, ⁇ c ⁇ 10 mole%,
• R a is a monovalent radical chosen from the group consisting of: halogens, hydrogen, a C 1 -C 6 hydrocarbon radical, a C 1 -C 6 polyester radical, a C 1 -C 6 nitrile radical or a C 2 -haloalkyl radical; -
• -C 6 o a radical comprising one or more silicon atom and a C 1 -C 6 polyether radical, and
• the anti-mist additive E (“antimisting" additive) is a branched polyorganosiloxane L or a mixture comprising at least one branched polyorganosiloxane L, said anti-mist additive E comprising at least one unit ⁇ SiOH and / or ⁇ SiR reagent; with R being a carbinol radical and having the following characteristics: - it is in a liquid form, possibly following dilution with a diluent
• At least one organosiloxane monomer, oligomer and / or polymer F having, per molecule, at least one reactive unit ⁇ SiH, with at least one monomer, oligomer and / or organosiloxane polymer G having, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a C 40 carbinol radical, in the presence:
• the nature and the amounts of the components F and G are determined in such a way that the ratio [number of reactive unit ⁇ SiH]: [number of reactive unit ⁇ SiOH and / or number of reactive unit ⁇ Si-carbinol] ⁇ 1: 1, preferably ⁇ 1: 2 and even more preferably between 1: 3 and 1: 50, and
• Component F is preferably a monomer, oligomer and / or organosiloxane polymer F which has, per molecule, at least one reactive unit ⁇ SiH and for general formula:
• R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 which may be identical or different, each independently represents one of the other: an alkyl radical linear or branched chain containing 1 to 20 carbon atoms, optionally substituted with at least one halogen, preferably fluorine, the alkyl radicals being preferably methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl, a cycloalkyl radical containing between 5 and 8 ring carbon atoms, optionally substituted, an aryl radical containing between 6 and 12 carbon atoms optionally substituted, and / or an aralkyl portion having an alkyl portion containing from 5 to 14 carbon atoms and an aryl portion containing from 6 to 12 carbon atoms, optionally substituted on the aryl portion by halogens and / or alkyls.
• component F By way of example of component F, mention may be made of polymethylhydrogensiloxanes with trimethylsiloxyl and / or hydrogenodimethylsiloxy ends.
• polymethylhydrogensiloxanes with trimethylsiloxyl and / or hydrogenodimethylsiloxy ends For example, the following compounds are particularly suitable for the invention:
• O ⁇ d ⁇ 500 preferably 1 ⁇ d ⁇ 50 and 0 ⁇ e ⁇ 500, preferably 1 ⁇ e ⁇ 150.
• the compound G is preferably a monomer, oligomer and / or organosiloxane polymer G which has, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a carbinol radical, and is selected from the group consisting of the structures of formulas (I) and (II): M 0 (D R ) P D q T r Q 5 (M R ), (II)
• R is a C 40 carbinol group
• R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 and R 21 which are identical or different, each independently represent one of the other: a linear or branched alkyl radical containing 1 to 20 carbon atoms, optionally substituted by at least one halogen, preferably fluorine, the alkyl radicals being preferably methyl, ethyl, propyl, octyl and 3,3,3 trifluoropropyl, a cycloalkyl radical containing between 5 and 8 cyclic carbon atoms, optionally substituted, an aryl radical containing between 6 and 12 optionally substituted carbon atoms, and / or an aralkyl part having an alkyl part containing between 5 and 14 atoms of carbon and an aryl part containing between 6 and 12 carbon atoms, optionally substituted on the aryl part by halogens and / or al
• the invention relates to a connected polyorganosiloxane
• the mixture comprising at least one branched polyorganosiloxane L ', characterized in that:
• At least one organosiloxane monomer, oligomer and / or polymer F having, per molecule, at least one reactive unit ⁇ SiH; with at least one monomer, oligomer and / or organosiloxane polymer G having, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a C 40 carbinol radical, in the presence:
• a dehydrogenation-condensation catalyst H which is a platinum-based metal catalyst
• the nature and the amounts of the components F and G are determined so that: a) the ratio: [number of reactive unit ⁇ SiOH]: [number of reactive unit ⁇ SiH] is between 1: 3 and 1: 50, and 2) isolating the anti-mist additive E, optionally after removal of the dehydrogenation condensation catalyst H and / or devolatilization and / or addition of a crosslinking inhibitor I '.
• the branched polyorganosiloxane L 'obtained according to the process described above contains reactive functions of the ⁇ SiH type and has the advantage of being in a liquid form which facilitates its use in the liquid silicone composition X precursor coating (s) silicone.
• the use of a platinum-based metal catalyst as dehydrogenation-condensation catalyst H makes it possible to obtain, surprisingly, a much more effective antimisting additive.
• R a is a monovalent radical selected from the group consisting of: halogen, hydrogen, a hydrocarbon radical -C 6O, a polyester radical -C 6O, a nitrile radical O -C 6 haloalkyl radical -C 6 O a radical comprising one or more silicon atom and a polyether radical -C 6 Q.
• the branched polyorganosiloxane L 'or mixture comprising at least one branched polyorganosiloxane L' has the average formula:
• M a D b Cdd with: - a, c and d are numbers> to 0, - b> 0,
• the invention also relates to a branched polyorganosiloxane L "or mixture comprising at least one branched polyorganosiloxane L" characterized in that: - said branched polyorganosiloxane L "comprises at least one reactive unit ⁇ SiOH and / or ⁇ SiR; carbinol
• At least one monomer, oligomer and / or organosiloxane polymer G having, per molecule, at least one reactive unit ⁇ SiOH and / or ⁇ SiR; with R being a C 40 carbinol radical, in the presence:
• the nature and the amounts of the components F and G are determined so that the ratio: [number of reactive unit ⁇ SiH]: [ number of reactive unit ⁇ SiOH and / or number of reactive unit ⁇ Si-carbinol] ⁇ 1: 1, preferably ⁇ 1: 2 and even more preferably between 1: 3 and 1: 50, and 2) isolating the anti-mist additive E, optionally after removal of the dehydrogenation condensation catalyst H and / or devolatilization and / or addition of a crosslinking inhibitor I '.
• Another subject of the invention relates to a liquid silicone composition X precursor coating (s) silicone comprising:
• At least one polyorganosiloxane A crosslinkable by polyaddition, by dehydrogenation, by polycondensation, cationically or by radical means and / or at least one K adhesion modulator system, and / or at least one crosslinking inhibitor D; and / or at least one crosslinking organosilicon compound B, and / or at least one catalyst or photoinitiator C the nature of which is chosen according to the type of reaction envisaged for said polyorganosiloxane A, and
• anti-mist additive E at least one anti-mist additive E ("antimisting") as described above.
• the last subject of the invention concerns the use of the anti-fog additive E as defined above to reduce the appearance of misting ("misting") during the coating of flexible supports with a liquid silicone composition X precursor coating (s) silicone.
• the invention proposes a simple, economical and reliable original means of combating the production of fog when coating flexible substrates (for example paper, film or polymer film) in coating devices. with cylinder operating at high speed.
• the practical industrial consequence is that the speeds of scrolling can be further increased without this phenomenon of fog harmful to the quality of the coating appearing.
• the control means proposed by the invention also has the significant advantage of not impairing the appearance qualities, the coverage, the anti-adhesion properties, and the mechanical properties (rub-off) of the cross-linked silicone coating that is sought to be obtained on at least one of the faces of the flexible support.
• the crude product formula determined by 29 Si NMR and 1 H is MD 52 from 3.4 to 16 M.
• Example 6 (Comparative to Example 5)
• a branched silicone of the empirical formula similar to Example 5 was prepared by redistributing 9.2 g of a resin of formula M OJ D 1 , 2 T 33 of 164.4 g of cyclic polysiloxane of formula D 4 (octamethylcyclotetrasiloxane), 16.6 g of a silicone oil of formula M 2 D 4 (tetradecamethylhexasiloxane) and 9.8 g of a polysiloxane with a SiH motif of formula MD'50M in the presence of Tonsil (montmorillonite sold by the company S ⁇ d-Chemie) at 75 ° C. for 20 h.
• Tonsil montmorillonite sold by the company S ⁇ d-Chemie
• the resultant silicone product obtained has a viscosity of 135 mm 2 / s.
• the crude formula of the product determined by 29 Si NMR and 1 H is MD 67 D ' 3. 6 T 0 , 5 M. It should be noted that the crude formula of this polymer is very close to that described for the polymer of the Example 5 Example 7 Post Functionalization
• a device (supplied by the company Ermap, Grenoble, France) with 2 rollers operating in a manner reproducible and able to scroll a strip of paper at a line speed of more than 900m / min.
• the two pressure / coating rollers have a diameter of 10 cm.
• the pressure roller is covered with rubber and the chromium casting cylinder.
• the coating roll has been dumbbelled so that the speed of the two rolls is synchronous.
• the pressure roller drivable by a motor is in constant pressure contact with the coating cylinder.
• the silicone coating liquid is poured directly into the gap between the two rollers.
• the amount of fluid used is 0.25 ml.
• compositions were then prepared by mixing a silicone polymer A1 (polydimethylsiloxane whose ends are blocked by a dimethylvinylsiloxy group whose viscosity is 220 mPa.s) and the products described above in Examples 4 to 7 at a rate of 2. parts by weight of product in 100 parts by weight of polymer.
• the compositions are homogenized with the roll-barrel the necessary time.
• the rotary system described above is then used on the rollers on which the preparation in question is spread.
• the rotational speed of the rollers is then gradually increased.
• the density of the fog is measured by placing a measuring instrument known as the particle counter marketed by the company ITS (France) near the point of contact between the cylinders.
• the result of the measurement of fog density is expressed in mg of silicone aerosol per m 3 of air at a given measuring speed.
• Example 5 invention
• Example 6 comparative
• the baths are obtained by successively mixing the following products: a silicone polymer of polydimethylsiloxane whose ends are blocked by a dimethylvinylsiloxy group whose viscosity is 220 mPa.s,
• the proportions of the mixture are calculated so that a ratio between the total number of moles of vinyl groups and the total number of moles of hydrogenosiloxane groups of 1.75, a platinum concentration of 1 10 ppm and ethynylcyclohexanol-1 level of the order of 0.15% by weight relative to the weight of the formulation.
• the anti-misting additive according to the invention is added to the polydimethylsiloxane silicone polymer whose ends are blocked by a dimethylvinylsiloxy group and whose viscosity is 220 mPa.s in a proportion of 2% by weight relative to the weight. total of the formulation.
• baths are then used successively to coat a paper support called "glassine" by means of a coating machine whose coating head is a head provided with four wet cylinders. Downstream of this head, a dryer in which circulates air at about 195 ° C is used to cure the silicone coating by bringing it to a maximum temperature of between 130 and I ⁇ O'C.

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