MXPA99007998A - Method and device for coating a substrate to provide it with antiadhesive properties, using a cross-linkable silicon composition - Google Patents

Abstract

The invention concerns a method for antiadhesive treatment by continuous coating of a paper strip, said coating containing a silicon composition with base of polyorganosiloxanes (POS) of the FC/LTC type. Said method consistsin the use of a POS A, a crosslinking agent B (hydrosilylation and/or dehydrogenation-polycondensation), a catalyst C, and optionally, an inhibitor D, an adherence modulator E and other compounds F. Said constituents A to F are continuously mixed in measured amounts, the mixing conditions being selected such that the bath average life DVB is<10H, that the bath homogeneity is such that its DSC (Differential Scanning Calorimetry) curve comprises a Gaussian peak, and such that the production flow rate of the A to F mixture is such that the duration d separating the moment when the constituents A, B and C are brought into the presence of one another and the moment when the mixture is applied to the unwinding strip, is not more than DVB. Said method also comprises the step (2) of conveying the composition to the coating site, the step (3) of coating the paper strip with the composition and the heat curing step (4).

Description

PROCEDURE AND DEVICE FOR JOINING A SUPPORT FOR CONFERING ANTI-ADHERENT PROPERTIES, THROUGH A COMPOSITION OF RETICULABLE SILICONE DESCRIPTION The field of the present invention is that of the silicone compositions crosslinkable by activation, which can be used above all to form a coating or an anti-adhesion film for fibrous support or not, for example paper or similar, or then polymer natural or synthetic More precisely, the invention relates to a method of continuously smearing a passing support strip (for example of paper, fabric, polymer), in order to confer anti-adherent properties; This smearing is carried out with the help of a silicone composition based on polyorganosiloxane (POS). The anti-adherent POS in which one is interested in the framework of the invention, are of the type of those that are crosslinkable, by hydration or by dehydrogen-polycondensation / thermally or by association of heat and radiation (UV radiation or beam of electrons). More specifically still, the POSs that are considered are, for example, those that are fast-curing and low-temperature (low temperature cure) -POS FC / LTC. The present invention also relates to the device and the silicone composition involved in the process of continuous baking, which is its main object. Classically, the anti-adherent silicone compositions comprise at least one POS A, a crosslinker B which is a POS and a catalyst. These ternary compositions may exist only in an ephemeral way to the non-crosslinked state. In fact, whatever the mechanism of crosslinking in question: hydrolyzation or dehydrogenpolycondensation, the POS of the SiH type put in the presence, in the first case, of POS of SiVi type and of hydrosilylation catalyst to platinum or put in presence , in the second case, of POS of SiOH or SiOR type and of condensation catalyst to platinum or tin, crosslink more or less short term. The speed depends above all on the reaction temperature.

On the other hand, it should be remembered that the POS that constitute these compositions can be presented, to the non-crosslinked state, to the pure state or in the form of crosslinkable liquid solutions or emulsions. As a result, for the anti-adherent treatments of supports (paper, fabric or polymer film), which consist of spreading the surface of these supports with the help of the above mentioned silicone compositions, it is imperative to carry out the application and the staggering of those compositions when they are in the form of non-crosslinkable liquids and therefore totally suitable for those operations. Once the supports are smeared with silicone compositions, they are subjected to heating in order to accelerate their crosslinking. Therefore, with regard to the above, two difficulties are easily noticed, among others that will arise as soon as anti-adhesion treatments are planned by smearing silicone, that is to say thermoplastic paper or film, of cadence and industrial scale. The first difficulty is related to the fact that the silicone systems (which put in pure POS, emulsion or solvent phase, etc. ..) that crosslink thermally and that are used customarily, need crosslinking temperatures between 100 ° C and 200 ° C. It is clear that at certain temperatures, it is difficult, even impossible, to plan the coating of certain supports such as thermoplastic films such as polyethylene, propylene, PVC and, to a lesser extent, polyethylene glycol terephthalate. These silicone systems are also characterized by lifetimes of DVB bath life greater than or equal to 10 hours and, in practice, between 12 and 24 hours. By DVB, the time required to double the dynamic viscosity measured at 30 ° C is designated. The dynamic viscosity can be measured with the aid of a BROOKFIELD viscometer according to the indications of the AFNOR NFT 761102 standard of May 1982. DVBs equal to or greater than 10 hours, leave the industrialists a sufficient margin to put into operation the smeared cadence and industrial scale, placing at the same time the limitations at a tolerable level. Unfortunately, the limitation imposed by the high crosslinking temperatures, in regard to the variety of the supports treatable by smearing anti-stick silicone, constitutes a major difficulty.

In addition, these high temperatures are harmful to the productivity and profitability of the spreadable treatments, due to the high cost of energy and the time required. To try to solve these difficulties, solvent-free silicone systems for anti-adhesion, thermally crosslinkable and claiming an application behavior called LTC (low temperature crosslinking) were proposed. These thermal silicone systems crosslink at temperatures between 60 ° C and 110 ° C. But unfortunately, the corollary of this advantageous decrease in crosslinking temperature represents a significant drop in DVB that can fall very clearly below 10 hours. These DVB are incompatible with the current industrial use limitations inherent to the treatment of silicone anti-adhesion by greasing. In fact, the preparation of the mixture forming the composition is generally carried out in batch mode (BATCH). In these techniques, the feeding of the spreading head from the mixing tank (s) necessarily implies stagnation times of the liquid silicone composition: before its application on the support. Therefore, it is easily conceived that, with short DVBs, gelling and mass-loading problems can intervene and be harmful to the quality of the spread.

In addition, the fact of being limited to preparing relatively large quantities of BATCH, can cause great economic damage as soon as it intervenes on the chain of greasing, any incident of a nature to interrupt the procedure. To summarize, the industrial procedures for silicone coating are not completely adapted to the LTC anti-adhesion silicone compositions, which correspond to what is best done today in the field of crosslinkable silicone systems for anti-adhesion. Its maladjustment is translated in terms of heavyness of method, low productivity and profitability, high cost and lower quality of the anti-adherent coatings that are obtained. More generally, manufacturers applying anti-adhesion silicone systems are waiting for a more universal spreading process in relation to the scale of substrates that can be coated with a coating obtained through thermal crosslinking. the conjugate effect of heat and radiation, that is to say that they authorize lower crosslinking temperatures, while preserving bath life durations for the non-crosslinked silicone composition, which are of an acceptable level and compatible with the industrial requirements of large-scale production and high cadences. It is also desirable to have crosslinkable silicone compositions well endowed with a high kinetics of crosslinking, so as to realize even more gains in productivity and profitability. The basic problem of the invention, therefore, can be summarized in the setting of a compromise between the temperature parameters of cross-linking / the life of the bath. In a more pragmatic way, the objective to be achieved would also be to develop an astute and optimal mixing technique, in relation to the industrial delays in the matter of caulking anti-adherent silicone and on an industrial scale. There is another brake to the optimization of the industrial processes of anti-stick silicone coating, which is linked to the fact that these compositions require very precise and reliable dosages of various ingredients. This is all the more complicated, as are the relationships between those ingredients - to - they are very important: base POS in relation to the crosslinker and in relation to the catalyst. Confronted with this problem, the inventors had the same merit: - on the one hand to show that it was convenient to simplify the management of the cross-linking / kinetic / DVB temperature parameters, no longer needing one of these parameters, namely the DVB; and - on the other hand, having put in place a continuous process of smearing which involves dosing steps, homogeneous mixing and feed of the smear head on the machine, whose procedure allows, surprisingly and unexpectedly, no longer need the DVB parameter. In this way, the present invention relates to a process of continuous greasing of a support strip that is passed to confer anti-adherent properties; this smearing is carried out with the aid of a silicone composition comprising: at least one polyorganosiloxane A, at least one crosslinker B crosslinkable by hydrosilylation and / or by dehydrogen-polycondensation and an effective amount of catalyst C, characterized in that it consists essentially of: 1) - in continuously mixing and in dosed quantities, in particular, the POS A or carriers carrying reactive groups GRa, the crosslinking agent (s) B carrying reactive groups GRb, and the catalyst C; 2) - to optionally carry out at least one premix AB and / or AC and / or BC when the latter can be made; 3) - to select the mixing conditions so that: * the DVB Bath Life is less than 10 hours, preferably 4 hours, and even more preferably 2 hours; * the homogeneity of the bath is such that its signature by differential DSC scanning calorimeter comprises at least one Gaussian peak that has: a peak-point CT temperature; a temperature T2 of highest peak part; a peak end temperature T3; that peak is characterized by: (i) T3 smaller or equal to 100 ° C, preferably smaller or equal to 90 ° C, and still more preferably smaller or equal to 80 ° C; (ii) ta -T = T3 smaller or equal to 20 ° C and more preferably smaller or equal to 15 ° C; T3 may eventually not satisfy the preceding parameter (i); and (iii) of ta-T = of ta-T ± 10 ° C; preferably = from ta-T ref ± 8 ° C; and more preferably = from ta-T ref ± 4 ° C; of the ta-T ref corresponds to T3 ref-TI ref, which is obtained from the DSC signature peak of a reference ABC mixture that is made according to the Pr protocol defined hereinafter; * the production flow of the homogeneous mixture is between a value that corresponds to the consumption rate of the mixture that determines the constitution of a buffer reserve; this value of the flow is such that the duration d separates the putting in the presence of the components A, B, and C and the moment of application of the composition ABC on the support strip that is passing, is less than or equal to the DVB; 2) - to route, simultaneously or not, the composition directly from the mixer to the spreading site (s); 3) - to spread the support strip that is going through, with the composition; 4) - in allowing thermal reticulation, if it occurs. The analysis by DSC (Differential Scanning Calor imetry) is carried out, in a manner known per se, with the aid of a METLER apparatus type A 4000, using the following operating parameters: increased temperature speed 10.0 ° C / minute; mass of the test tube: 15 mg; I work in an open aluminum crucible. One of the essential principles that govern the present invention, refers to the combination of a process of dosing and homogeneous mixing of the compounds according to the composition of anti-stick silicone glue, putting into action appropriate means and taking into account the obligation to act on judiciously selected parameters. These parameters are: - the duration of the bath that is lowered beyond 10 hours and that acts on the nature and / or the proportions of the components A, B, C, and / or of their possible premixes; - the homogeneity of the mixture that is mastered through the DSC signature, which allows a staggering in relation to a reference mixture; - and the production flow of homogeneous mixture that adjusts to the consumption rate with or without formation of buffer reserve of greasing. The mixture provided and homogenized in this way, is sent directly on the spreading head of the machine, so that only the amount of mixture necessary to feed the spreading head is prepared (for example with a buffer reserve of 10 to 30). minutes of consumption). The advantages of the method according to the invention are numerous. Above all, mention may be made of: reducing the crosslinking temperature of the mixtures used, resulting in the possibility of thermally spreading and crosslinking thermosensitive supports such as, for example, PE, PP, PVC PET films. possibility of working with silicone systems whose DVB is less than 10 hours and by lowering to values as low as those that are less than 2 hours; - continuous preparation of the minimum amount of mixture necessary for feeding the greasing head, which leads to the reduction of losses in the event of an incident that interrupts the greasing treatment; - Reliability and precision of the dosing of the components in proportions that can descend to 1 to 100 or below 1 to 100 and this same when operating with small flow rates; the accuracy can be of the order of 2% of which results an increased regularity of the quality of the finished products; elimination of the risks of dosage error that come from the methods of preparation of the mixture in BATCH by heavy manuals; - Elimination of the risks of contamination of the gels that come from the automatic systems of preparation of the mixtures in BATCH; - improvement of productivity: decrease in labor time and loss of material. Simplification of the flow of silicone raw materials; - easy preparation of the mixture: less maintenance and less hard work, therefore reduced risk of incidents; - flexibility of use in the change of dosing ratio and speed of putting into operation on the machine; less loss of material, rapidity in manufacturing changes; gain of operator time on the machine for non-productive tasks. The inventors have the merit of having put in place a method of continuous greasing, which allows to use industrially, systems of thermal silicones that crosslink (polyaddition or dehydrogenpolicondensation) at such low temperatures and with DVB as short as those that are inferior 10 hours This innovation requires both the expertise of the chemistry of silicones and a mastery of precise dosing technologies in the proportions, that is to say of the order of 1 to 100 and continuous intimate mixing of the more or less viscous products that can be used at a small flow rate. On the other hand, this process has an interest for the implementation of all silicone systems without solvent, with solvent, or with the type of emulsion thermally crosslinkable (polyaddition or dehydrogenating condensation) possibly associated with radiation, intended for Thin layer of anti-stick coating on any support: paper, polymer or textile. Advantageously, the protocol Pr that allows to establish the reference mixture ABC to reach the comparative parameter of delta-R-ref of the DSC peaks of the mixture, consists of mixing the same constituents A, B, C, in the same proportions to perform in a container, a mixture of 250 cm3, under moderate agitation with the help of a rotating propeller that rotates at 1000 revolutions per minute for at least 15 minutes, at room temperature (25 ° C). In practice, the buffer can be determined by the two cylinders together, operable in rotation in the opposite direction and constituting the spreader head. For example, this reserve is comprised between 10 and 30 minutes of consumption of the composition that serves to effect the greasing. The rate of consumption in the greasing depends on the speed of passage of the support strip, the width and the nature of the latter (absorbent power), as well as the viscosity of the crosslinkable silicone composition and the importance of the deposit (g / m2) desired. According to step 2 of the process, the routing of the composition, at least partially mixed, tos the spreading head, is carried out simultaneously or not, as it is possible to plan the implementation of static mixing means or dynamic, traveled by a flow of matter; this flow is produced by means of feeding or routing, such as for example pumps, and in particular volumetric pumps, or storage containers under pressure.

According to a preferred arrangement of the invention relating to stage 1, mixing conditions A, B, C are put into operation, such as the homogeneity that is obtained, is translated by a DSC peak in which the parameters (i), ( ii) and (3i) are cumulatively satisfied. This corresponds to a LTC / FC silicone system, knowing that such systems, if preferred according to the invention, are not for that reason exclusive of other silicone systems that crosslink at a higher temperature and / or a little less quickly. In order to optimize the smelling conditions as much as possible, the dynamic viscosity at 25 ° C of the homogeneous mixture must be less than or equal to 10 000 MPa.s, preferably less than or equal to 1000 mPa.s. In accordance with a preferred embodiment of the invention, the method of smearing comprises a previous stage 0 consisting of: * premixing A and B and / or A and C when it can be made; * And / or put in place an AB premix.

A, B, C are the base compounds of the composition proper to the process according to the invention. But in fact, it is preferable to add other ingredients, adopting or not the method variants consisting of premixing of these supplementary ingredients with the compounds A, B, C. In this way, it can be advantageously incorporated: at least one of the compounds of game A, B and C; - and / or to premix AB and / or BC when the latter can be made; - or in the bath containing the compounds A, B and C; M at least one D-inhibitor for cross-linking (this is particularly the case when silicone systems that cross-link by hydrosilylation are put into operation); * and / or at least one adhesion modulator E; * and / or at least one other component F. It should be understood that: - when the composition according to the method of the invention contains, beside the compounds A, B and C, the optional ingredients D and / or E and / or F; - the analysis by DSC as well as the protocol Pr, which have been mentioned in the foregoing, will then be related to the mixture constituted by A, B and C and D and / or E and / or F. According to a mode still More preferred embodiment of the invention, is acted in such a way that stage 1 is decomposed as follows: - 1 'premix (stage 0) of compounds A, B + possibly D and / or E and / or F; - 1"then homogeneous mixture of the premix (ie AB, ABD, ABDE, ABDEF, ABE, ABF, ABDF, ABEF) with compound C. Without this being limiting, POS A is preferably selected: in the group comprising: - the POSs that have, per molecule, at least two GRa groups, located in the chain and / or in the (the) end (s) of the chain, each consisting of an alkenyl group in c2 ~ c10 bonded to the silica, preferably vinyl; - and its mixtures; while the crosslinker B consists of at least one POS having, per molecule, at least two and, preferably, at least three GRb groups each consisting of a hydrogen atom bonded to the silica, located in the chain and / or at the end (s) of the chain; A reacts with B for hydrosilylation. For this type of compounds A and B, it could be shown that the GRb / GRa molar ratio should advantageously be in the range from 1 to 5, preferably from 1.1 to 3 and more preferably still from 1. 5 to 2.5. Here, it is the framework in which the man of the trade is in a position to find the ideal molar proportions to respect the operative parameters of the invention, as defined in the foregoing and in applying them in the case of compounds A and B crosslinkable by hydrosilylation. Examples of POS A are the (dimethyl) -polysiloxanes of di-ethylvinylsilyl ends, the copolymers (methyl) - (dimethyl) -siloxanes of trimethylsilyl ends, the copolymers (methyl) - (dimethyl) -siloxanes of dimethylvinylsilyl ends, the (methylvinyl) ) - cyclic polysiloxanes. Examples of the crosslinker B are dimethyl (dimethyl) -siloxanes, dimethylhydrogenosilyl, (methylhydrogen) -polylysiloxanes of trimethylsilyl termini, copolymers (dimethyl) - (methylhydrogen) -poly-siloxanes of trimethylsilyl ends, cyclic (methyl-hydrogeno) -polysiloxanes, M'Q resins constituted by motifs (CH3) ) 2HSiO.¡ / 2 And Yes? 2. Polyaddition silicone composition bases may only comprise linear POS such as for example that described in the patents: US No. 3 229 172, 3 697 473, 4 340 709 or also include branched or network POS as for example that which is described in US Pat. Nos. 3 284 406, 3 434 366. According to a variant, POS A is selected from: - polydiorganosiloxanes carrying at least two condensable or hydrolysable GRa groups, located in the chain and / or in the chain end (s), each consisting of an OR group linked to the silica wherein R is a hydrogen atom or an alkyl radical at C-j_-C6; - and its mixtures; whereas the crosslinking agent is of type POS B carrying GRb = H; A reacts with B by dehydrogen polycondensation; and wherein the molar ratio GRb / GRa is in the range from 1 to 5, preferably from 1 to 3. Examples of POS A crosslinkable by dehydrogenpolycondensation are the (dimethyl) -polysiloxanes of hydroxydimethylsilyl or alkoxydimethylsilyl ends or dialkylmethylsilyl with alkoxy which is methyloxy, ethyloxy or propyloxy. The POS, which can consist of the compounds A and B of the dehydrogenating-polycondensation ring systems can also present, in this case, a linear, possibly branched, cyclic or network structure. In the case of the effective amount of catalyst C in relation to other components A and B, it is understood a concentration in C necessary and sufficient to allow crosslinking according to the kinetics required by the method according to the invention and to achieve the characteristics of use, expected in the application of anti-adherent coating. In the case of a silicone system crosslinking by hydrosilylation, all conventional hydrosilylation catalysts can be put into operation in the process according to the invention. Particular preference is given to platinum-based catalysts, in particular catalysts of the Karstedt type. In this way, the polyaddition catalyst C is preferably selected from the platinum and rhodium compounds. In particular, the complexes (Karstedt) of platinum and of an organic product which is described in US Pat. Nos. 3,159,601, 3,159,602, 3,202,972 and European patents EP No. 0 057 978 and EP 0 can be used. 1190 530, or else the complexes (Karstedt) of platinum and vinyl organosiloxanes which are described in US Pat. Nos. 3 419 593, 3 715 334, 3 337 432 and 3 814 730. To fix the ideas, it can be indicated that it is preferable that the amount or concentration of C be between 10 and 250 ppm of catalyst taken to the metallic state, preferably 30 to 200 ppm and more preferably still 50 to 150 ppm, relative to the amounts of compounds A and eventually D and / or E, which are put into work. The catalysts C which are put into operation in the type of crosslinking by dehydrogen polyacondensation, are either platinum-based catalysts such as those mentioned above, or are the classical condensation catalysts composed of at least one metal that belongs to the tin group; this last metal is particularly preferred. For example, it may be dilaurate, dibutyl tin. Catalyst C, when it is platinum based, is put into operation in the proportions indicated in the foregoing, when it is tin-based, its quantity, expressed in ppm of tin metal in relation to the amounts of compounds A and eventually D and / or E, is comprised between 1000 and 5000 and preferably between 2000 and 4000. In the preferred variant of the invention, according to which an inhibitor D is made to intervene in a system where the cross-linking between A and B intervenes at least in part, according to a hydrosilylation mechanism, privileges are given to selected D-inhibitors in the group comprising: alpha-acetylenic alcohols, azodicarboxylates; preferred are maleic esters, and mixtures thereof, trimethyl-7, 7, l-dodecin-l-ol-3 (TMDDO) and ethynyl-cyclohexanol (ECH). As an example of a hydrosilylation reaction inhibitor, which may be employed, there may be mentioned those described in French patent application No. 2 207 553 which relates to the long chain alpha-acetylenic alcohols. On the other hand, the content of this patent application is integrally incorporated herein by reference. In the case of D-inhibitors of the azodicarboxylate type, one will refer to the European patent application No. 0 1184 965 which describes in detail such type of cross-linking reaction inhibitors by polyaddition. The content of this patent application is also included entirely in the present application by reference. As examples of azodicarboxylate-type inhibiting compounds, ethyl azodicarboxylate can be mentioned. In the case of inhibitors D of the maleic ester type, one will refer to the French patent application No. 2 456 767 which describes in detail the inhibitors of that type. The content of this patent application is also included entirely in the present application by reference. As an example of an inhibitor compound of this type, mention may be made of di-n-butyl maleate, diallyl maleate. In the case of another optional compound of the silicone composition specific to the process of the invention, namely the adhesion modulator E, it is preferably selected from the group of compounds formed by: - the POS-modulating resins of the Si-alcentyl function described in French patent application No. 2 704 553 (resins referred to in that document; RM "Si alcenilo") '; - POS modulating resins of SiH function which are described in French patent application No. 2 704 553 (resins referred to in that document; "SiH" RM); - POS modulating resins of Si-OH function, consisting of at least two different siloxy types "M" (R3SÍO- 2), "Q" (Si02) and / or "T" (RSi o) and possibly "D" »(R2SÍO2 / 2); the organic radicals are identical or different and represent alkyl or cycloalkyl groups in C ^ -C ^ g or phenyl, at least 80 mol% of organic radicals representing a methyl group; that resin contains at least 0.1 mole%, preferably from 0.5% to 5 mole% of hydroxyl groups bonded to silicon with a ratio number of "M" motifs / number of "Q" and / or "T" motives of 0.6-1; the number of possible "D" motifs is 0.5-10 per 100 moles of resin; - mixtures of two or more of the two above-mentioned resins, each other; - mixtures of at least one of the above-mentioned resins with the solvents called "reagents" described in French patent application No. 2 704 553 (it is recalled that the content of this patent application No. 2 704 553 is fully included in the present application by reference).

As examples of resins that enter into the constitution of the adhesion modulator E according to the present invention, the following resins will be cited: MDVlQ wherein the vinyl groups are included in the D motifs; MMVlQ where the vinyl groups are included in a part of the M motifs; MD 'Q where the hydrogen atoms bonded to silicon are included in the D motifs; MM'Q where the hydrogen atoms bonded to silicon are included in the M motifs; MQ (OH) where the hydroxyl groups bonded to silicon are included in the M motifs; As already indicated above, the mixture prepared according to the process of the invention may advantageously comprise at least one other compound F constituted: (i) by an organic aliphatic and / or aromatic solvent not participating in the reaction; this solvent is preferably that in which A and / or B are dissolved to form a solution representing the form under which A and / or B are put into operation in the process; and / or (2i) by water in the case of the implementation of an emulsion system. According to a preferred feature of the invention, the concentration of inhibitor D is less than or equal to 0.5% by weight, preferably 0.2% by weight and more preferably still 0.15% by weight, relative to the amount of compounds A and eventually E. The possibility of using such small concentrations of inhibitor D is a great advantage above all on the economic plane. Obviously, this advantage is well inherent in the continuous process according to the invention. The presence of a supplementary additive of the organic type, which does not participate in the reaction, preferably aliphatic or aromatic, is to be related to the possibility offered by the invention of putting the starting compounds into use in the form of a solution. In fact, the POS A or B resins, even the compounds C, D and E can be fed dosed, mixed and routed to the spreading head, in the form of a solution. According to an alternative, the compounds A, B, C, D, E can be used in the form of an emulsion. In accordance with an interesting provision of the invention, the action is taken in such a way that the admission of dosed quantities of the constituents A, B, C, possibly D and / or E and / or F, to the level of the eventual site or sites. Premix and / or of the mixing sites of C with the other components, is carried out sequentially and interatively. Thus, in the case where it is for example in accordance with a previous step 1 ', of a premix of the compounds A, B, C, it is foreseen that the supply of the circuits with these 3 compounds, is operated from successively according to for example A / B / D, or AD / B / A, repeated during the continuous operation of the procedure. According to another feature of the invention, the operations of mixing and possibly premixing, are subdivided into a stage of mixing behind the flow and a stage ahead of the flow. The step of mixing back of the flow corresponds to a contacting of all or part of the compounds, while the step of mixing in advance of the flow, constitutes in fact an operation of intimate and homogeneous mixing of the mentioned compounds with eventual addition of the (of the) missing compound (s). In practice, the organization of the material flow according to repeated sequences of several stratifications of each compound, for example A, B, D or A, B, D, C, advantageously finds its place behind the flow or of the premixing sites or mixed forward of the flow. As already stated in the foregoing, one of the elements of the invention is related to the continuous dosing of the compounds of the composition. To carry out this operation, recourse is made in a privileged manner for each constituent A, B, C, possibly D and / or E and / or F of the composition, to a dosing means, especially volumetric ones that can ensure the feeding in dosed amount of each one of them as well as, at least partially, its circulation according to a continuous flow, along each operative chain. In the case of the mixing operations of even possible pre-mixes, there is advantageous recourse to static or dynamic mixing means. The inventors selected, in addition to the main parameters of this procedure mentioned above, other parameters of which it is wise to take into account to ensure a good development of the procedure. Thus, advantageously, the parameters that must also be considered for the premix and / or the mixture are: - the speed of passage of the support strip; the rate of consumption of the composition when greased; - the lifetime of the DVB bathroom; the feed rates of the constituents A to F at the level of the mixing sites even of premix; - the flow rates at the outlet of the premix mixture; - the flow velocity of the mixture even of the premix flow; - the duration that separates the presence of C with the necessary constituents to the reaction and the deposit of the mixture on the support strip. According to another of these aspects, the present invention relates to a device especially for the implementation of the procedure as defined above. This device is characterized in that it comprises: - Metering means, especially volumetric, of the components A, B, C, possibly D and / or E and / or F; optional means of premixing the components other than C, means of homogeneous mixing of the components A, B, C, possibly D and / or E and / or F; - at least one greasing organ of the support strip passing through; - means for routing the homogeneous mixture of the mixing site (s) (means) to the spreading organ, and optionally of the premixing site (s) (means) to the mixing means; and heating means of the support strip; these means preferably consist of at least one tunnel kiln. Advantageously, the optional premixing means comprise at least one premixing chamber behind the flow and static pre-mixing means in advance of the flow, and the homogeneous mixing means comprising at least one mixing chamber behind the flow and static mixing means forward of the flow. As a greasing organ, all the systems that can spread a thin layer can be used; for example, the systems will be cited; «Size press», sheet air, Meyer bar, «direct gravure» head, «multi-cylinder» head. Advantageously, the greasing organ consists of a "direct gravure" or engraved cylinder head or a "multi-cylinder" head, well-known in the paper industry: The structure and operation of that device will be better understood upon reading the description below, which is given by way of non-limiting example, of a preferred embodiment of that device, as well as of the examples of putting into operation the process of continuously smeared according to the invention, with the help of that device. The description of the device is made referring to the appended figure 1 which represents a synoptic diagram of the preferred embodiment of the device according to the invention. The latter comprises means 1 for volumetric dosing of compounds A, B, D and E, which are respectively a POS, a crosslinking agent, an inhibitor and a catalyst for example of platinum or tin, depending on whether the systems are of the polyaddition type. or dehydrogenpolycondensation. The device also comprises means 2 of premixing the non-C components, means 3 of homogeneous mixing of the constituents A, B, D, C, a smearing organ 4, roughening means 5 of the premix or homogeneous mixture. of the premixing and mixing sites respectively towards the smear organ 4, and heating means 6 of the passing support strip 7.

For example, a metering means 1 are volumetric counters, that is mechanical gear elements that allow accurate measurement of a volume of product. Each volumetric counter 1 is arranged between a power supply of compounds A, B, D, or C and the pre-mixing means 2, for which it refers to the constituents A, B, D, and the means 3 of homogeneous mixing, for what refers to the catalyst C. Each volumetric counter 1 behaves like a dosing pump that takes the right amount of compounds to inject into the mixing circuit. An electro-valve 8 is provided on the connection connecting each volumetric counter 1 to the pre-mixing and mixing means 2 and 3, respectively. The latter comprise a premix chamber 2. 1 at the rear of the flow and mixing 3.1 in the same part of the flow, each connected by a duct 5 forming the routing means, to a static premix chamber at the front of flow 2.2 and to a mixing chamber static in the front forward part of flow 3.2, respectively. The chambers located in the back of flow 2.1 and in the front of flow 2.2, allow the premixing of compounds A, B, D, while the chambers in the back of flow 3.1 and in the front of flow 3.2 , they allow the homogenous and intimate mixture of premix A, B, D with catalyst C. Each chamber in the rear part of streams 2.1 and 3.1, is an organ: (i) of static mixing known per se, constituted for example by a cylinder comprising toric, coaxial channels; and (2i) transit of the introduced materials. Each channel can be equipped with mixing blades. Such an organ makes it possible to ensure the first contact of the products.

The chambers of the front part of streams 2.2 and 3.2 are static mixers of a type known per se consisting of a hollow cylinder, provided at the interstate with mixing stators (vanes) and through which, the silicone composition A, B, D , or A, B, D, C, can migrate at the same time that is agitated and mixed, in a homogeneous and intimate way. A solenoid valve 8 is provided on the duct 5 between the chamber at the front of the flow 2.2 and the chamber at the rear of the flow 3.1. The static mixers that are put into operation in this device, are arranged in line in the routing means 5 (channeling) constituted for example by a flexible element.

Advantageously, the greasing member 4 is a multi-cylinder head constituted by two smooth cylinders 9.1 and 9.2 defining the greasing head in front of which the end of the routing means 5 opens. The cylinders 9.1 and 9.2 are glued and can be operated in rotation according to opposite directions. The organ 4 also comprises a relay cylinder 10 bonded to the pair of cylinders 9.1 and 9.2 and ensure the union of that pair with a pair of cylinders 11.1 and 11.2, in the air gap, of which the support strip 7 circulates to eventually receive the one smeared on that site, of a silicone composition A, B, D, C, crosslinker. This ointment body 4 is known per se. According to a preferred feature of the invention, the end of the roughening means 5 of the mixture is subdivided into two branches 12.1 and 12.2 which make it possible to ensure a feed at two points of the dosing cylinders 9.1 and 9.2, with the intimate homogeneous mixture A , B, D, C, crosslinkers. Preferably, each of these two feed points is disposed in the vicinity of one end of the injection head 9.1 / 9.2. According to some variants, injection points could be provided along the air gap of the dosing cylinders 9.1 and 9.2.

The latter define a damping reserve of the intimately and homogeneously mixed composition A, B, D, C. Thanks to the cylinder 10 and the press 11.1 / 11.2, this composition is transferred and applied to the support strip 7, which it is passing at a given speed in the direction indicated by the arrows in the drawing. This strip smeared on one side then passes through the heating means 6, which are advantageously a tunnel kiln of the type known in the technical field under consideration. The volumetric counters 1, the electrovalves 8, the smear organ 4, the passing strip 7, and the tunnel-oven 6, can be attached to a central control and calculation unit that allows the programming of the dosing parameters. , flow rate, consumption rate in reactive bath and crosslinking temperature, among others. According to variants of the invention, thermal crosslinking means, other means for activating crosslinking, for example actinic irradiation or electron beam, could be provided as a complement. By way of non-limiting example of the dosing and continuous mixing means that can be used in the device according to the invention, those described in the French patent application No. 2 508 635 and in the utility model can be cited. German N ° 296 06 710 (DOPAG).

EXAMPLES EXAMPLE 1: JOINT TESTS IN CONTINUOUS OF A COMPOSITION OF RETICULABLE ANTI-ADHERENT SILICONE THERMALLY BY HIDROSILILATION OF A GROUP POS REAGENT GRa = Si-Vi, WITH THE HELP OF A REAGENT GROUP POS GRb = Si-H. 1.1.- Material and raw materials: The device that is put into work is the one that is represented in figure 1 and that is described above.

More precisely, there is recourse in this example to a dosing and continuous mixing apparatus of the VOLUMIXR type marketed by the DOPAG Company. The greasing organ consists of a five-cylinder greasing head. The tunnel kiln has the following characteristics: hot air blown by nozzle on the greased face according to 3 zones of 2 meters long each, with an air flow of 1800 m3 per hour and per zone. The compounds A, B, D, C, which are put into operation are the following: - premixed compounds A and D: POS A formed by an oil consisting of a copolymer (methylvinyl) - (imethyl) -polysiloxane ends dimethyl-vinylsilyl containing 0.031 mol of vinyl per 100 grams; this oil is charged at the height of 0.15% by weight of inhibitor D constituted by an alpha-acetylenic alcohol: trimethyl-3-7-11 dodecin-l-ol-3 (TMDDO); - compound A: this is the vinyl POS oil that is put in place to prepare the AD premix; - crosslinker B: mixture comprising 70% by weight of POS of the type (methylhydrogen) -polylosiloxanes of trimethylsilyl ends and of 30% by weight of resin M'Q constituted by motifs (CH - ^^ HSi? - / 2 and SiO2) This mixture contains 1.35 mol of SiH functions per 100 grams, - Catalyst C: Platinum catalyst of the Karsdedt type consisting of a 2000 μm solution of platinum metal in a dimethylvinylsilyl polydimethylsiloxane oil, this solution contains 0.041 mol vinyl per 100 grams Therefore, the device comprises 4 power sources as constituent of the composition, namely, AD, POS B, POS A, and catalyst C. 1.2.- Calibration of volumetric counters: The volumetric counters 1 affected to the power supplies AD, B and A, on the one hand, and power supply C, on the other hand, are regulated in such a way that the proportions that are put into work are the following: (AD + B + A): C - 100 in weight: 6 parts by weight, be 1 20 ppm of Pt in relation to A + D. In the same way the volumetric counters 1 that correspond to AD, B and A are regulated in such a way that the proportions between these constituents are the following: AD: A - 66 parts by weight : 33 parts by weight; (AD + A): B - 100 parts by weight: 4.5 parts by weight; With these proportions: the SiH / SiVinil molar ratio is equal to 1.8; the amount of inhibitor D is equal to 0.10% in relation to the total mass of A. It is still found that the DVB of the mixture is only 35 minutes. 1.3.- Other parameters: The following parameters are also set as indicated below: Output flow of the mixer: 51 grams per minute; Capacity of the cushioning reserve of the greasing organ: 200 grams; Consumption rate of the crosslinking composition: 3 kilograms per hour; Speed of passage of the strip; 150 meters per minute; Temperature gradient in furnace-tunnel: 110 ° C, 2nd zone: 100 ° C and 3rd zone: 100 ° C. 11.4.- Operation The device is put into operation and the 5-cylinder greasing head is fed continuously for 3 hours with the mixture of AD, B, A and C products. The greased paper with the help of this greasing organ is a glasin type paper. The deposit is made at a rate of 1 g / m2. It is reticulated in line by step in an oven-tunnel, at a temperature of the order of 100 ° C, the speed of passage is 150 meters per minute. This continuous operation is carried out without any notable problem. In particular there is no gelation. The quality of the anti-stick coating obtained is completely satisfactory. The feeding of compounds AD, B and A was carried out by the volumetric meters and / or by a pump, for example pneumatic and / or by providing the pressure under the tanks that constitute the power sources of the various constituents.

Regulation of an opening of electrovalves 8 is programmed in such a way that the feeding of the pre-mixing 2 and mixing 3 means is done according to iterative sequences AD / B / A, on the one hand and ADB / C, on the other hand, respectively. The programming of the control unit of course integrates the variations or the regulation parameters of the volumetric counters and the solenoid valves. 1.5.- Evaluation of the procedure: The characterization of the homogeneous mixture obtained from the ingredients A, B, D, C, is carried out by differential thermal analysis DSC with the help of a METLER device type TA 4000: the curve that is given in Figure 2, allows access to the following values (which also gives the device): - Peak temperature TI: 60.5 ° C; - Temperature T2 of highest part of peak: 70.3 ° C; - T3 temperature of peak end: 80.4 ° C; - From ta T = T3-T1: 19.9 ° C; It is also found: - Del ta T ref: 18.7 ° C; - From ta T = Del ta T ref: + 1.2 ° C; The visual quality of the mixture obtained from the ingredients A, B, D, C is also appreciated, initially having colored the catalyst C. It is observed that the result obtained is satisfactory since the coloration of the mixture is homogeneous EXAMPLE 2: TESTS TO DIFFERENT CONCENTRATIONS OF INHIBITOR D: The conditions are the same as in the previous example 1, except in what relates to the parameters given in table 1 below.

TABLE 1 TMDDO 5% in relation to A 0.15% 0.05% Pt = = 120 pp TI 72.9 ° C 43.6 ° C T2 (5) 80.6 ° C 56.9 ° C T3 88.4 ° C 72.3 ° C DVB 4 hours 15 minutes Comments: Very reactive systems of silicates with very short DVB can be put into operation, which lead to a satisfactory final product with the required requirements.

Claims (6)

1. R E I V I N D I C N O N S 1.- Continuous smearing process of a support strip that is being passed to confer anti-adherent properties; This smearing is carried out with the aid of a silicone composition comprising at least one polyorganosiloxane A carrying reactive groups GRa, at least one crosslinking crosslinker B carrying reactive groups GRb and crosslinkable by hydrosilylation and / or by dehydrogenpolycondensation and an effective amount of catalyst C, and optionally a crosslinking inhibitor D and / or at least one adhesion modulator E and / or at least one other constituent F, characterized in that it consists essentially of: 0) in carrying out continuously at least one premix AB and / or AC and / or BC when the latter can be done; and then 1) - in continuously carrying out a homogeneous mixture of constituents A, B, and C; stages 0 and 1 are conducted: (Ij) by selecting the nature and proportions of constituents A, B. and C; (2j) optionally incorporating at least one of the starting constituents A, B, and / or in the pre-mix and / or in the bath containing the constituents AB and C, at least one constituent D and / or F, and (3j) ) putting in conditions of pre-mixing and homogenous mixing, where the precise dosing of the constituents is carried out continuously, so that: * the DVB Bath Life is such that its signature by means of differential calorimetry DSC sweep, understand at least one Gaussian peak that presents: a peak-point CT temperature; a temperature T2 of highest peak part; a peak end temperature T3; that peak is characterized by: (i) T3 equal to or less than 110 ° C; (ii) From ta-T = T3 - Ti equal to or less than 30 ° C; AND (iii) From ta-T = from ta -T ref ± 10 ° C; The ta-T ref corresponds to T3 ref - TI ref, which is obtained from the DSC signature peak of a reference mixture A, B, C and possibly D and / or E and / or F which is made according to the Pr protocol; * the flow rate of production of the homogeneous mixture is between a value that corresponds to the consumption rate of the mixture on the (or) site (s) of smearing and a value that determines the constitution of a buffer reserve; this value of the flow is such that the duration d separates the putting in the presence of the components A, B, and C and possibly D and / or D and / or F, and the moment of homogeneous application on the support strip that is passing, is less than or equal to the DVB; 2) - to route, simultaneously or not, the homogeneous mixture directly from the mixer to the spreading site (s); 3) - to spread the support strip that is going through, with the composition; 4) - in allowing thermal reticulation, if it occurs.
2. 2. Method according to claim 1 characterized in that the dynamic viscosity at 25 ° C of the homogeneous mixture is less than or equal to 10 000 MPa.s.
3. 3. Method according to claim 1 or 2, characterized in that a pre-mixing stage of A and B and optionally D and / or E and / or F is provided, followed by a step 1 of homogeneous premix mixing with C.
4. 4. Method according to any of claims 1 to 3, characterized in that the POS A is selected in the group comprising: - the POS having, per molecule, at least two groups GRa, located in the chain and / or in the end (s) of the chain, each consisting of an alkenyl group at C2-C-I_Q bonded to the silica; - and its mixtures; while the crosslinker B consists of at least one POS having, per molecule, at least two GRb groups each consisting of a hydrogen atom bonded to the silica, located in the chain and / or at the end (s) ) of the chain; A reacts with B for hydrosilylation. and wherein it is acted in such a way that the molar ratio GRb / GRa is in the range from 1 to 5.
5. 5. Process according to any of claims 1 to 4, characterized in that the POS A is selected in the group comprising: - the polyorganosiloxanes carrying at least two condensable or hydrolysable GRa groups, located on the chain and / or chain end (s), each consisting of an OR group linked to the silica where R is an atom of hydrogen or an alkyl radical in cl-c6- - and mixtures thereof; and in that the crosslinker B is of the type POS B carrying GRb = H; A reacts with B by dehydrogenpolycondensation; and wherein the molar ratio GRb / GRa is in the range from 1 to 5.
6. 6. The method according to any of claims 1 to 4, characterized in that the crosslinking between A and B intervenes at least in part according to a hydrosilylation mechanism, and wherein the inhibitor D is selected from the group comprising: the alpha-acetylenic alcohols, the azodicarboxylates; the maleic esters, and their mixtures. 1 - Method according to any of claims 1 to 6, characterized in that at least one adhesion modulator E is put into operation, which is selected from the group of following compounds: POS modulating resins of function Si alcenyl; - POS modulating resins with SiH function; - POS modulating resins of Si-OH function, consisting of at least two different siloxy types "M" (R3SÍO-L / 2), "Q" (Si02) and / or "T" (RSiO) and possibly " D »(R2SÍO2 / 2); the organic radicals are identical or different and represent alkyl or cycloalkyl groups in C 1 -C-LQ O phenyl, at least 80 mol% of organic radicals representing a methyl group; that resin contains at least 0.1 mol%, of hydroxyl groups bonded to silicon with a ratio of "M" motifs / number of "Q" and / or "T" motives of 0.6-1; the number of possible "D" motifs is 0.5-10 per 100 moles of resin; the mixtures of two or more of two of the abovementioned resins, each other; - or mixtures of at least one of the above-mentioned resins with the so-called "reactive" solvents. 8. Process according to any of claims 1 to 7, characterized in that the mixture that is prepared comprises at least another compound F constituted: (i) by an organic aliphatic and / or aromatic solvent that does not participate in the reaction; this solvent is preferably that in which A and / or B are dissolved to form a solution representing the form under which A and / or B are put into operation in the process; (2i) and / or with water 9- ~ Process according to any of claims 1 to 8, characterized in that it acts in such a way that the admission of dosed quantities of constituents A, B, C, possibly D and / or E and / or F, at the level of the eventual premixing sites and / or the mixing sites of C with the other components, is carried out sequentially and iteratively. 10. Process according to any of claims 1 to 9, characterized in that for each constituent A, B, C, possibly D and / or E and / or F of the composition, a means of dosing is placed on the all volumetric that can ensure the feeding of dosed quantities of each one of them as well as, at least partially, their circulation according to a continuous flow, along each operative chain. 11. Device for the implementation of the method according to any of claims 3 to 10, characterized in that it comprises: - Metering means, especially volumetric, of the components A, B, C, possibly D and / or E and / or F; - means for premixing the components other than C; means for homogeneously mixing components A, B, C, possibly D and / or E and / or F; - at least one greasing organ of the support strip passing through; - means for routing the homogeneous mixture of the mixing site (s) (means) to the spreading organ, and optionally of the premixing site (s) (means) to the mixing means; and - means for heating the greased support strip. 12. Device for the implementation of the process according to claim 11, characterized in that the possible pre-mixing means, comprise at least one premixing chamber behind the flow and static premixing means in advance of the flow; and wherein the homogeneous mixing means comprises at least one mixing chamber behind the flow and static mixing means in advance of the flow. 13.- Crosslinkable silicone composition, characterized in that it is constituted by the homogeneous product mixture obtained at the end of the stage, as it exists before spreading in the process according to any of claims 1 to 10.