Method for acylating a hydroxylated solid material

Abstract

The invention relates to a method for chromatogenic acylation of a solid material (1, 2) carrying hydroxyl groups capable of reacting with fatty acid chlorides in the gaseous state, wherein: a reactive fatty acid chloride composition (20, 21, 22) is applied to the surface of the solid hydroxyl material (1, 2) by means of an applicator capable of releasing the composition (20, 21, 22) on the surface of the material (1, 2). According to the invention, the composition (20, 21, 22) is applied to the surface of the solid hydroxyl material (1, 2) at an acylation temperature lower than the vaporisation temperature of at least one fatty acid chloride of the composition (20, 21, 22) to allow acylation of the material (1, 2) by reaction of at least one fatty acid chloride in the gaseous state of the composition (20, 21, 22) with at least one of the hydroxyl groups of the material (1, 2), the acylation temperature being between 160°C and 250°C.

Description

Description Title of the invention: PROCESS FOR ACYLATING A HYDROXYLATED SOLID MATERIAL

[0001] The invention relates to a process for the chromatogenic acylation of a hydroxylated solid material, i.e. a solid material carrying reactogenic hydroxyl groups (-OH), accessible and capable of reacting with a fatty acid chloride in the gaseous state.

[0002] Throughout the text, the term "chromatogenic" and the expression "by chromatogeny" qualifying the acylation reaction, indicate and recall that this acylation reaction or more simply "acylation" occurs between a hydroxylated solid material such as a paper support considered in the field of separative gas chromatography (GC), as the stationary phase and a fatty acid chloride reagent at least partially in the gaseous state and considered as an eluate entrained in liquid / vapor equilibrium by the mobile gas phase consisting of a flow of a hot gas phase.

[0003] W02012 / 066015 discloses a semi-industrial process for the chromatogenic acylation of a strip of a cellulosic substrate such as paper, driven in unwinding between an upstream unwinder and a downstream winder. According to this semi-industrial process, fatty acid chloride (R-CO-Cf) in the liquid state is deposited at a fixed upstream station by means of a cylinder, called an anilox, on the paper of the paper strip driven in unwinding and is then heated downstream of the deposition to a temperature allowing acylation. A fraction of fatty acid chloride passes into the gaseous state due to the increase in the saturated vapor pressure of the fatty acid chloride, linked to the increase in the heating temperature. Gaseous fatty acid chloride reacts with reactogenic hydroxyls in the paper to form ester bonds between the paper and the hydrocarbon chain (R) of the fatty acid chloride, according to the following equation (I): Paper-OH + R-CO-Cf Paper-O-CO-R + HCC (I).

[0004] Chromatogenic acylation is advantageously carried out without organic solvents or catalysts so that their removal is not necessary at the end of the reaction. Acylation is promoted by the removal of gaseous hydrochloric acid (HC C) produced due to acylation, which is driven by the application of a flow of hot air to the cellulose substrate during acylation. The entrainment of the gaseous hydrochloric acid formed makes it possible to shift the reaction equilibrium in the direction of the formation of the acylated cellulose substrate.

[0005] The inventor has however found that the method of WO2012 / 066015 is not optimized. On the one hand, the acylated cellulose substrate according to WO2012 / 066015 has a hydrophobicity that is qualitatively inferior to that of an acylated cellulose substrate obtained by impregnating the substrate with a chloride solution. of fatty acid in pentane and then heating the impregnated substrate by applying a hot gas flow. This process does not make it possible to give the cellulosic substrate optimal hydrophobicity and, where appropriate, water impermeability^) and sufficiently durable over time. He found that the contact angle of a drop of pure water deposited on the surface of an acylated cellulosic substrate according to the process of W02012 / 066015 is certainly greater than 90°, but remains lower than the optimal value of 150° obtained by applying the solution of fatty acid chloride in pentane. This results in unsatisfactory hydrophobicity properties.On the other hand, it does not allow the paper of a paper web - in particular a web of heavy-weight special paper and / or porous paper with a high specific surface area and / or paper with a surface layer of polyvinyl alcohol - to be effectively acylated when driven at a speed greater than 50 meters per minute. The process of W02012 / 066015 is in reality incompatible with implementation on an industrial scale. Indeed, optimal acylation of such a paper web could only be obtained at the cost of excessive deposition of fatty acid chloride and / or excessive heating of the paper which would (in)evitably lead to deterioration and / or browning of the latter.

[0006] The invention aims to overcome the aforementioned drawbacks of the method of WO2012 / 066015.

[0007] Also known from WO2022 / 033698 is a process for the solvent-free chromatogenic acylation of a piece of paper heated to a temperature of 160°C and on which stearic acid chloride in the liquid state is deposited by means of an applicator roller whose applicator surface is formed of a velvet. In this process, neither the velvet nor the applicator roller are heated, so that the stearic acid chloride loaded on the velvet is necessarily at a temperature lower than the acylation temperature during deposition, in particular at a temperature between room temperature and the acylation temperature. The piece of paper is then subjected to a subsequent heat treatment to finalize the acylation. The process of WO2022 / 033698 makes it possible to confer satisfactory hydrophobic properties on the acylated piece.On the other hand, the method of WO2022 / 033698 is not fully developed to allow the acylation of the paper of a paper web driven in unwinding at very high speed, in particular at a running speed greater than 100 meters per minute. Despite the improvements made by WO2022 / 033698, ungrafted liquid fatty acid chloride necessarily remains on the paper. On the one hand, such an excess is not economically acceptable. Such an excess is also not functionally acceptable. The residual liquid fatty acid chloride is likely to be hydrolyzed during prolonged storage of the acylated paper, releasing hydrochloric acid. The acid. The released hydrochloric acid can deteriorate cellulose fibers and cellulosic material, affecting its mechanical strength. In addition, the fatty acid released as a result of this hydrolysis reduces the hydrophobicity and water impermeability of the acylated paper. This excess must therefore be eliminated. The process of WO2022 / 033698 must be optimized and its economic efficiency must be improved.

[0008] The invention aims to overcome this drawback.

[0009] The invention therefore aims to propose an improved process for the chromatogenic acylation of a solid material bearing hydroxyl groups accessible to at least one fatty acid chloride in the gaseous state and capable of being able to react with this / these fatty acid chloride(s) in the gaseous state.

[0010] The invention therefore aims to propose such a chromatogenic acylation process whose acylation yield is improved.

[0011] The invention also aims to propose such an improved method making it possible to increase the speed of chromatogenic acylation.

[0012] The invention also aims to propose such a chromatogenic acylation process making it possible to give a hydroxylated solid material satisfactory hydrophobic properties.

[0013] In particular, the invention aims to provide such a chromatogenic acylation process making it possible to confer satisfactory hydrophobicity properties on a hydroxylated solid material with a reduced quantity of fatty acid chloride.

[0014] But the invention also aims to propose such a process for the chromatogenic acylation of a hydroxylated solid material and for transforming this hydroxylated solid material into an acylated material of substantially the same porosity as the starting hydroxylated solid material.

[0015] The invention aims to propose such a method for the chromatogenic acylation of a hydroxylated solid material which can be implemented in a traditional manner by any individual using commonly available means.

[0016] But the invention also aims to propose an industrial process for acylation of a strip of paper during its movement between an upstream reel of said strip of paper and a downstream winding device of a strip of acylated paper.

[0017] In particular, the invention therefore aims to propose such an industrial chromatogenic acylation process which is compatible with the technical constraints relating to the movement of the solid material and to a high production rate of such an acylated solid material.

[0018] The invention aims in particular to propose such a method making it possible to deposit the desired quantity - in particular a significant quantity, in the case of special solid materials - of fatty acid chloride, while allowing the solid material to move at high speed.

[0019] Furthermore, the invention also aims to provide such a chromato-acylation method genetic which does not require the use of an environmentally toxic organic solvent, particularly an apolar organic solvent, for its implementation.

[0020] But the invention also aims to propose such a chromatogenic acylation process making it possible to limit the quantity of residual fatty acid chloride at the end of the acylation.

[0021] The invention also aims to propose such a chromatogenic acylation process making it possible to deposit an optimal quantity of reactive fatty acid chloride, relative to the number and / or density of reactogenic hydroxyls, accessible and capable of being able to react with the fatty acid chloride in the gaseous state.

[0022] The invention thus aims to propose such a chromatogenic acylation process allowing a substantially stoichiometric acylation of the reactogenic hydroxyls of the solid material.

[0023] The invention also aims to propose such a chromatogenic acylation process allowing acylation of different solid materials, in particular special solid materials such as corrugated cardboard and / or papers coated with polyvinyl alcohol.

[0024] The invention also aims to propose such a chromatogenic acylation process making it possible to reduce or even completely eliminate the step of eliminating excess fatty acid chloride.

[0025] The invention therefore aims in particular to propose such a simplified process since it does not require a final step of eliminating residual ungrafted fatty acid chloride.

[0026] To this end, the invention relates to a method for the chromatogenic acylation of a solid material bearing hydroxyl groups accessible to at least one fatty acid chloride in the gaseous state and capable of being able to react with this(these) fatty acid chloride(s) in the gaseous state, in which: at least one composition, called reactive composition, of at least one fatty acid chloride is applied at least to the surface of said hydroxylated solid material by means of at least one device - in particular an applicator roller - having an applicator surface formed of filiform elements which are non-reactive with said reactive composition and capable of being able to release - and apply - said reactive composition at least on the surface - that is to say on the surface and, where appropriate,in depth over at least part of the thickness of said hydroxylated solid material by contact of the filiform elements - in particular by contact of the filiform elements driven in rotation by the roller - and of the hydroxylated solid material; characterized in that said reactive composition applied - in particular released upon contact with said hydroxylated solid material - by the applicator device at least on the surface of said hydroxylated solid material is, during its application, at a temperature, called acylation temperature, lower than the temperature of, vaporization of at least one - in particular of each - fatty acid chloride of said reactive composition and chosen to allow acylation of said solid material by reaction of at least one - in particular of each - fatty acid chloride in the gaseous state of said reactive composition on at least one of the hydroxyl groups of said solid material, said acylation temperature being between 160°C and 250°C.

[0027] The inventor has discovered that, in a completely surprising and counter-intuitive manner, it is in fact advantageous to apply, i.e. to deposit and distribute, said reactive composition on the hydroxylated solid material by providing that said applied reactive composition is at said acylation temperature of between 160°C and 250°C during application, i.e. at a temperature high enough to allow acylation of the hydroxylated solid material by acid chloride in the gaseous state, without going through a prior step of depositing said reactive composition in the liquid state, by means of an applicator device necessarily chosen and intended to allow the application of a liquid composition.It was realized that the filiform elements forming the applicator surface of the device - in particular of a roller or a brush - applicator used in the context of the present invention, when it is impregnated with said reactive composition brought to said acylation temperature of between 160°C and 250°C - higher than the deposition and distribution temperature described in WO2022 / 033698 - and brought briefly into contact with the surface of the hydroxylated solid material, itself brought to said acylation temperature, allows a more efficient acylation of the hydroxylated solid material than when said liquid reactive composition is deposited at low temperature in essentially liquid form and then heated subsequently to the deposition at said acylation temperature.The inventor observed that bringing the hydroxylated solid material and said reactive composition into contact at said acylation temperature makes it possible to increase the speed of the acylation reaction, making it compatible with implementation of the process on an industrial scale, by allowing the acylation of the hydroxylated solid material of a strip of hydroxylated solid material, in particular of the paper of a strip of paper, driven in unwinding.Although said high acylation temperature shifts the liquid / vapor equilibrium of the fatty acid chloride(s) of said reactive composition in the direction of an increase in the gaseous fraction of said reactive composition, this gaseous fraction, which could be expected to diffuse freely away from the filiform elements of the applicator device and the hydroxylated solid material, making it non-reactive with respect to this hydroxylated solid material, appears to remain in reality confined within the filiform elements and appears to react efficiently and very quickly with the hydroxylated solid material. The filiform elements forming the applicator surface of the applicator device appear to behave as a reservoir of chloride(s). of fatty acid(s) in the gaseous state, the fatty acid chloride(s) in the gaseous state appearing to be retained by the threadlike elements. Furthermore, the increase in the reaction rate of the fatty acid chloride in the gaseous state with the hydroxyls of the hydroxylated solid material makes it possible to shift, with an equivalent time constant, the liquid / vapor equilibrium of the fatty acid chloride in the direction of vaporization. The reaction is, therefore, also improved and accelerated.

[0028] This increase in the acylation reaction rate makes it possible to produce a plurality of successive deposits of fatty acid chloride(s) on the hydroxylated solid material and at said acylation temperature, in particular on the paper of a moving paper web, each deposit of the plurality of deposits providing a sub-stoichiometric quantity of fatty acid chloride(s) relative to the reactogenic hydroxyls of the hydroxylated solid material. In these embodiments, the stoichiometric quantity of fatty acid chloride(s) can be achieved due to the multiplicity of successive deposits. In addition, each sub-stoichiometric deposit of fatty acid chloride(s) makes it possible, during each deposit, to promote the dispersion of the fatty acid chloride(s) deposited at said acylation temperature on the surface of the hydroxylated solid material, thus promoting its reactivity.

[0029] But even more surprisingly, without this observation being able to be supported by a known theory, the retention of the fatty acid chloride(s), in particular the fatty acid chloride(s) in the gaseous state, at the level of the filiform elements does not seem to prohibit the interaction of the fatty acid chloride(s) in the gaseous state and the hydroxylated solid material. The fact that the filiform elements trapping the fatty acid chloride(s) in the gaseous state, come into contact with the surface of the hydroxylated solid material seems to break the confinement of said reactive composition, in particular its gaseous fraction, in the filiform elements and allows a rapid reaction, favored by the high temperature of said reactive composition, with the hydroxyls of the hydroxylated solid material. According to the inventor's expression, the gaseous fraction of the fatty acid chloride(s) of said reactive composition appears to be "sucked up" by the hydroxylated solid material.

[0030] This apparent phenomenon of suction of the fatty acid chloride(s) in the gaseous state confined in the filiform elements actually seems to make it possible to overcome the effect of a layer, called the boundary layer, gaseous extending on the surface of the hydroxylated solid material and limiting, or even opposing, the approach by diffusion of the fatty acid chloride(s) in the gaseous state to the reactive hydroxyls of the hydroxylated solid material. The use of a device - in particular a roller or a brush - applicator having an applicator surface formed of filiform elements seems to make it possible to de- applying and distributing fatty acid chloride(s) in the gaseous state in contact with the hydroxylated solid material, bypassing the effect of said boundary layer. The applicator device heated to said acylation temperature makes it possible to solve the hitherto unsolved problem of the existence of said boundary layer on the surface of the hydroxylated solid material.

[0031] The method according to the invention makes it possible to give the solid material satisfactory or even excellent hydrophobic properties, in particular as evaluated by measuring the Cobb index and / or by measuring the contact angle formed by a drop of water deposited on the surface of the acylated solid material and / or by the leaktightness test of a pocket of water.

[0032] But it also allows, in the context of the chromatogenic acylation of a hydroxylated solid material of great thickness and / or great porosity and / or great specific surface area, such as a high-grammage paper material, corrugated cardboard or a solid material coated with polyvinyl alcohol, to carry out a plurality of successive hot deposits allowing a substantially stoichiometric acylation of the hydroxylated solid material of great thickness and / or great porosity and / or great specific surface area.

[0033] According to certain embodiments of a method according to the invention, at least one part of the applicator surface of the applicator device being in contact with a part of the surface of the hydroxylated solid material, at least this part of the surface of the hydroxylated solid material is at said acylation temperature during the application of said reactive composition to the hydroxylated solid material. According to these embodiments of a method according to the invention, the solid material is heated prior to the application of said reactive composition. In these embodiments, the solid material is heated in the absence of said reactive composition. Advantageously, the heating of the solid material prior to the application of said reactive composition allows for - at least partial - dehydration of the solid material.

[0034] According to certain embodiments of a method according to the invention, the filiform elements forming the applicator surface are at said acylation temperature during the application of said reactive composition to the hydroxylated solid material.

[0035] According to certain embodiments of a method according to the invention, said reactive composition is applied at least to the surface of said hydroxylated solid material, in a thermoregulated enclosure adapted to maintain said reactive composition released by the applicator device at said acylation temperature.

[0036] According to certain embodiments, the method according to the invention comprises at least one step of redistribution of fatty acid chloride(s) deposited on the hydroxylated solid material, without further addition of said reactive composition, the redistribution step being carried out by means of at least one distributor device having an applicator surface formed of filiform elements which are non-reactive with the fatty acid chlorides of said reactive composition and capable of being charged with fatty acid chloride deposited on the hydroxylated solid material, by contact of the filiform elements of the distributor device and the hydroxylated solid material and to release at least a portion of the charged fatty acids, upon contact with said hydroxylated solid material by contact of the filiform elements and the hydroxylated solid material, the distributor device being at a temperature of between 160°C and 250°C. Such a high-temperature redistribution step promotes the gaseous state of the fatty acid chloride(s) previously supplied and their reactivity.

[0037] Advantageously, the filiform elements of the applicator device and / or the distributor device are flexible and deformable in contact with the hydroxylated solid material and adapted to be able, due to this flexibility, this deformation and the movement of the applicator device and / or the distributor device relative to the hydroxylated solid material, to release fatty acid chloride on the surface and in depth over at least part of the thickness of the hydroxylated solid material or to take fatty acid chloride from this surface.

[0038] According to certain embodiments of a method according to the invention, the applicator surface of the applicator device and / or the distributor device is formed of a velvet provided with the filiform elements. The material forming the filiform elements is further chosen to withstand said acylation temperature, without loss of its adsorbent and / or applicator properties.

[0039] According to certain embodiments of a method according to the invention, said acylation temperature is between 160°C and 250°C, in particular between 165°C and 240°C, particularly between 170°C and 230°C, more particularly between 180°C and 220°C, preferably between 190°C and 220°C, more preferably between 200°C and 220°C. Said acylation temperature is adapted according to the solid material to be acylated. In particular, said acylation temperature is chosen to be lower than the browning temperature of the solid material. That being said, according to the invention, taking into account the acylation speed due to the hot deposition of said reactive composition and the reduced duration of exposure of the solid material to high temperature, the risks of browning of the solid material due to the high temperature are reduced.

[0040] According to certain embodiments of a method according to the invention, at least one - in particular each - reactive composition comprises at least one fatty acid chloride chosen from the group formed by palmitic acid chloride (C10), stearic acid chloride (C18), arachidic acid chloride (C20) and behenic acid chloride (C22). Nothing prevents the provision that said reactive composition comprises a small proportion of acetyl chloride (CHs-CO-Cf). The inventor has discovered that acetyl chloride, which is not a fatty acid chloride within the meaning of the invention, is capable of reacting spontaneously and rapidly with free water molecules present in the solid material, preserving from possible hydrolysis the fatty acid chlorides intended for acylation. The inventor has also observed that, surprisingly, acetyl chloride does not react with the free and accessible hydroxyl groups of the solid material, nor with said reactogenic hydroxyls of other hydroxylated polymers such as polyvinyl alcohol. Furthermore, advantageously, the acetic acid produced by hydrolysis of acetyl chloride is sufficiently volatile to be removed from the solid material. Advantageously, acetyl chloride is used as a protector of the fatty acid chloride(s) of said reactive composition.Advantageously, acetyl chloride is used as a trans-chlorination reagent to restore fatty acid chlorides from hydrolyzed free fatty acids.

[0041] According to certain embodiments of a method according to the invention, the hydroxylated solid material is a paper material. It may be a solid material - that is to say a material that is neither liquid nor gaseous - hydroxylated, consisting essentially of cellulose and having free, accessible hydroxyl groups that are reactive with respect to fatty acid chlorides in the gaseous state. The hydroxylated solid material may also be a hydroxylated solid material - in particular a paper or a cardboard, for example a corrugated cardboard - having an outer surface layer formed of polyvinyl alcohol.

[0042] Said reactive composition(s) may be applied to the hydroxylated solid material with a total quantity chosen so that the hydroxylated solid material has a surface quantity of deposited fatty acid chloride(s) of between 1 mg and 500 mg per square meter (mg / m 2 ) of geometric surface of said hydroxylated solid material. The quantity of fatty acid chloride(s) applied to the hydroxylated solid material is between 1 mg / m 2 and 500 mg / / m 2 of hydroxylated solid material. Advantageously, a plurality of successive deposits are carried out at said acylation temperature so as to achieve a substantially stoichiometric acylation of the hydroxylated solid material.

[0043] In certain embodiments, the applicator device is an applicator brush whose filiform elements are chosen to withstand said acylation temperature. In these embodiments, the method according to the invention can be implemented manually in an artisanal manner.

[0044] According to certain methods of implementing on an industrial scale a process according to the invention, the hydroxylated solid material is formed from a strip of paper driven in a scrolling direction parallel to the most large dimension of the strip, between an upstream reel of said paper strip and a downstream winder of a strip of acylated paper. The increased reactivity of the acid chloride(s) deposited at high temperature allows the implementation of the method according to these embodiments. In these embodiments, the paper of the paper strip can be driven at high speed, in particular greater than 50 m / min, preferably greater than 100 m / min. In these embodiments, at least one - in particular each - reactive composition is applied at a fixed station(s) at least on one main face of the paper driven in unwinding. According to these modes of implementation on an industrial scale of a method according to the invention, the reactive composition(s) is (are) applied on the fly by means of an applicator device fixed and immobile relative to the paper driven in unwinding.According to these methods of implementing on an industrial scale a method according to the invention, at least one - in particular each - applicator device is a roller with an axis of rotation parallel to the plane of the paper web and not parallel - in particular orthogonal - to the direction of travel. According to some of these methods of implementation, the paper web being a low-grammage paper web, said reactive composition(s) is(are) applied to the paper web with a total quantity chosen so that the paper web has an average surface quantity of fatty acid chloride(s) of between 1 mg and 50 mg per square meter (mg / m. 2) of flat (geometric) surface of the paper strip. However, according to certain other embodiments, the paper strip being a cardboard strip - in particular corrugated cardboard - or a paper strip coated with polyvinyl alcohol, said reactive composition(s) is (are) applied to the paper strip with a total quantity chosen so that the paper strip has an average surface quantity of fatty acid chloride(s) greater than 50 mg per square meter (mg / m 2 ) of flat surface of the paper strip - in particular up to 500 mg / m 2 , and adapted to allow (stoichiometric) acylation of almost all reactogenic hydroxyls.

[0045] In certain embodiments, the method according to the invention comprises at least two applications of reactive composition(s) at fixed stations on the paper web being driven while moving, each reactive composition(s) being at said acylation temperature during its application. According to this embodiment of a method according to the invention, a small quantity of fatty acid chloride(s) is applied at said acylation temperature so as to allow rapid and substantially quantitative acylation and this application is repeated several times to achieve substantially stoichiometric acylation of the paper of the paper web.

[0046] In some embodiments, the solid material is a paper material coated with polyvinyl alcohol. The increased reactivity of the chloride(s) of acid(s) deposited at high temperature allows the implementation of the method according to these embodiments, including when the surface polyvinyl alcohol is at a temperature above its melting temperature and is in a sticky state.

[0047] According to certain embodiments of a method according to the invention, the filiform elements are formed from at least one material chosen from the group formed by aramid fibers and microfibers - in particular Kevlar® (micro)fibers - and inorganic fibers and microfibers - in particular glass (micro)fibers and carbon (micro)fibers. The filiform elements are formed from at least one fibrous or microfibrous material that is resistant to temperature, resistant to acidic environments and resistant to abrasion caused by the running of the paper web. The filiform elements are formed from at least one fibrous or microfibrous material that is inert with respect to the fatty acid chloride(s) of said reactive composition.

[0048] According to certain embodiments of a method according to the invention, at least a portion of gaseous hydrochloric acid formed due to the chromatogenic acylation is entrained by a flow of a gaseous composition circulating in contact with the solid material - in particular countercurrent to the paper web being driven as it moves - at said acylation temperature. The remote entrainment of the gaseous hydrochloric acid formed due to the chromatogenic acylation reaction makes it possible to shift the equilibrium of the reaction in the direction of acylation of the hydroxylated solid material and / or the paper material.The displacement of the hydrochloric acid formed makes it possible to avoid deterioration of the cellulose fibers of the paper material and more generally of the solid cellulosic material and a deterioration of its mechanical strength qualities, the hydrochloric acid formed and not displaced being likely to promote hydrolysis of ester bonds and a release of acylation groups in the form of free fatty acids. The displacement of the hydrochloric acid formed also makes it possible to prevent the fatty acids released due to this hydrolysis from affecting the barrier properties of the acylated solid material.

[0049] According to certain other embodiments of a method according to the invention, the filiform elements of at least one applicator roller are supplied by centrifugal diffusion of said reactive composition from an axial lumen of this applicator roller driven in rotation on itself. In certain of these embodiments, said reactive composition is introduced into the axial lumen of the applicator roller by means of a ramp for distributing said reactive composition over substantially the entire length of the axial lumen, the distribution ramp extending over substantially the entire length of the axial lumen. According to certain embodiments, the distribution ramp is mounted so as to oscillate along the longitudinal axis of the distribution ramp and along the axis of rotation of the applicator roller.

[0050] In these embodiments, the axial lumen of the applicator roller is adapted to accommodate a ramp for supplying the applicator roller with reactive composition and for distributing said reactive composition over the entire length of the axial lumen. The distribution ramp may be provided with dispersive orifices for said reactive composition, distributed along the distribution ramp so as to be able to distribute said reactive composition over the entire length of the axial lumen of the applicator roller.

[0051] Any other method of feeding the filiform elements is possible. According to certain other embodiments of a method according to the invention, the filiform elements are adapted to be able to be loaded with said reactive composition by contact between the (external) applicator surface - in particular driven in rotation - of the applicator device and a dispensing device for said reactive composition. In certain of these embodiments, the dispensing device may comprise a printing device comprising a cylinder, called an anilox roll, having a plurality of hollow cells formed on the external surface of said anilox roll and of predetermined dimensions and volumes adapted to control the quantity of said reactive composition transferred onto the applicator device.

[0052] In certain advantageous embodiments, at least one applicator roller is provided with means for heating said reactive composition to said acylation temperature. In these advantageous embodiments, the filiform elements forming the applicator surface of the roller advantageously act as an applicator reservoir for fatty acid chloride(s), in particular fatty acid chloride(s) in the gaseous state.

[0053] According to certain embodiments of a method according to the invention, at least one applicator roller is rotated with an angular rotational speed chosen so that the peripheral ends of the filiform elements are rotated with a linear speed of a value distinct from the value of the running speed of the paper strip. In these other embodiments, the linear running speed of the free ends of the filiform elements and the running speed of the paper strip are not synchronized. The application of said reactive composition on the surface and in depth of the solid material by touching said surface and projecting said reactive composition in depth is improved.

[0054] According to certain embodiments of a method according to the invention, at least one applicator roller is rotated in a direction of rotation chosen so that the peripheral ends of the filiform elements are driven counter to the movement of the paper strip.

[0055] According to certain other embodiments of a method according to the invention, at least one applicator roller is driven in rotation in a direction of rotation chosen so that the peripheral ends of the filiform elements are driven in concurrent scrolling relative to the scrolling of the paper strip.

[0056] According to certain embodiments of a method according to the invention, a sample of fatty acid chloride(s) - in particular excess fatty acid chloride(s) - on the paper strip is carried out by means of a recovery device having a rotating recovery surface and provided with filiform elements, non-reactive with said reactive composition and capable of being able to: take on fatty acid chloride(s) by contact between the recovery surface and the paper strip, and - releasing fatty acid chloride(s) by applying a flow of gaseous composition heated to a temperature higher than said acylation temperature - in particular to a temperature between said acylation temperature and the vaporization temperature of each fatty acid chloride of said reactive composition -,

[0057] According to certain embodiments, the flow rate of gaseous composition is applied in contact with the recovery surface of the recovery device and / or in contact with the moving paper web.

[0058] A solid material - in particular a paper web - is formed which is acylated and substantially free of residual fatty acid chloride(s) and hydrochloric acid. The flow of gaseous composition is applied in contact with the paper web and countercurrently to the direction of travel of the paper web so as to entrain at least a portion of hydrochloric acid in the gaseous state formed due to the acylation.

[0059] According to the invention, said reactive composition is free from any solvent medium (with the exception of possible traces), in particular from any apolar solvent medium distinct from the fatty acid chloride(s).

[0060] The invention also relates to an acylated solid material that can be obtained by a method according to the invention. The invention also relates to an acylated solid material obtained by a method according to the invention.

[0061] The invention also relates to a process for the chromatogenic acylation of a solid material bearing hydroxyl groups accessible to at least one fatty acid chloride in the gaseous state and capable of being able to react with this / these fatty acid chloride(s) in the gaseous state, characterized in combination by all or part of the characteristics mentioned above or below. Whatever the formal presentation given thereof, unless explicitly indicated otherwise, the different characteristics mentioned above or below must not be considered as closely or inextricably linked to each other, the invention being able to relate to only one of these structural or functional characteristics, or only part of these characteristics structural or functional, or only part of one of these structural or functional characteristics, or any grouping, combination or juxtaposition of all or part of these structural or functional characteristics.

[0062] Other aims, characteristics and advantages of the invention will appear on reading the following description which refers to the appended figures and to the examples given solely as a non-limiting example of the invention, and in which:

[0063] [Fig 1] Figure 1 is a block diagram illustrating a chromatogenic acylation process known from the prior art (WO2022 / 033698) and presented solely for comparison with a process according to the invention,

[0064] [Fig 2] Figure 2 is a block diagram illustrating a first embodiment of a chromatogenic acylation method according to the invention,

[0065] [Fig 3] Figure 3 is a block diagram illustrating a second embodiment of a chromatogenic acylation method according to the invention, and

[0066] [Fig 4] Figure 4 is a schematic representation of a device for implementing an industrial process for chromatogenic acylation of a width of paper according to the invention.

[0067] The known process of WO2012 / 066015, for the chromatogenic acylation of a paper material comprising depositing liquid fatty acid chloride on the paper material by means of a cylinder, called an anilox roll, designed for printing, is not satisfactory. The paper material obtained by such a known process contains a significant residual quantity of free fatty acid chloride, despite the implementation of a final blowing (or "flushing") step. Residual fatty acid chloride can decompose by hydrolysis in the form of free fatty acid and hydrochloric acid which can degrade the solid material. In addition, the free fatty acids formed impair the barrier properties of the solid material and the residual fatty acid chlorides pose a toxicity problem for applications in particular in the field of food packaging and in the biomedical field.

[0068] Also known from WO2022 / 033698 is a process for the chromatogenic acylation of a paper handkerchief. According to this known process, stearic acid chloride is deposited by means of a lacquer roller impregnated with stearic acid chloride at room temperature, on one of the faces of the handkerchief heated to a temperature of 160°C. The quantity of stearic acid chloride impregnated on the lacquer roller and the quantity deposited on the handkerchief are adjusted by successive applications, without reloading the roller, and exhausting the stearic acid chloride until the optimal quantity of acid chloride impregnated on the roller is obtained. The handkerchief having received the optimal quantity of stearic acid chloride is then placed in an oven at a temperature of 160°C. Such a known process is not applicable as it stands on an industrial scale.

[0069] The known chromatogenic acylation process described above is illustrated in Figure 1. Such a known process comprises a step 2' of heating a paper material 1' in an oven heated to a temperature, called the acylation temperature, lower than the vaporization temperature of the fatty acid chloride, but sufficient to allow acylation of the paper material 1' by reaction of a gaseous fatty acid chloride 5' with reactogenic hydroxyls of the paper material 1'. In this known process, a hot paper material 6' is formed at said acylation temperature. In parallel, a 3' lacquer roller having an applicator surface formed of a 4' velvet is impregnated by rolling 7' in 5' acid chloride in the liquid state at atmospheric temperature under rolling conditions adapted to obtain an 8' lacquer roller in an optimal state of impregnation allowing a deposit of an optimal quantity of 5' stearic acid chloride in the liquid state.In this known method, a step 9' of applying stearic acid chloride 5' in the liquid state and at atmospheric temperature to the hot paper material 6' is carried out by rolling the impregnated lacquer roller 8' over the hot paper material 6', allowing acylation of the hot paper material 6' by stearic acid chloride in the gaseous state, at a temperature necessarily lower than said acylation temperature and the formation of an acylated and hydrophobic material 10'. According to this known method, stearic acid chloride at room temperature and essentially in liquid form is deposited on a paper material heated to a temperature sufficient to allow chromatogenic acylation of the paper material by stearic acid chloride in the gaseous state formed due to the temperature of the paper material.

[0070] A block diagram of a process according to the invention for the chromatogenic acylation of a solid material 1 bearing hydroxyl groups accessible to at least one fatty acid chloride in the gaseous state and capable of being able to react with this / these fatty acid chloride(s) is represented in figure 2.

[0071] The hydroxylated solid material 1 may be a cellulosic material. The solid material 1 may also be formed from a fabric, in particular a fabric comprising cotton fibers. The solid material 1 may be a paper material. However, any type of hydroxylated solid material may be used. The hydroxylated solid material 1 may have an irregular surface condition. It may have significant roughness. However, the hydroxylated solid material 1 may also be a material - in particular calendered paper - having a regular surface condition and low roughness. The hydroxylated solid material 1 may be porous or non-porous. The hydroxylated solid material 1 may be a non-porous material having hydroxyl groups carried by a polymer - in particular PVA (polyvinyl alcohol) forming the free surface of the hydroxylated solid material. The hydroxylated solid material 1 may be a paper material made non-porous and airtight by surface application of a layer of PVA, as described in FR2925910. The hydroxylated solid material 1 may be a disposable paper handkerchief formed from a plurality of cellulosic sheets with a grammage of less than 30 g / m 2 -notably less than 20 g / m 2 preferably between 10 g / m 2 and 30 g / m 2 , more preferably between 10 g / m 2 and 20 g / m 2-. The paper material may be formed from crosslinked cellulose fibers whose rotational mobility is restricted, giving the paper material improved properties of mechanical strength in general and mechanical strength in wet conditions ("wet-strength") in particular. The cellulose fibers are then linked together by hydrogen bonds and by covalent bonds formed with at least one group of crosslinking atoms, such as for example a derivative of l-chloro-2,3-epoxypropane or epichlorohydrin. The hydroxylated solid material 1 may be a flexible material, that is to say it is deformable under the effect of its own weight. The hydroxylated solid material 1 may be a paper material in the form of a sheet of paper called "paper towel", toilet paper, a paper napkin, or filter paper. The hydroxylated solid material 1 may be cardboard.It may be rigid, that is to say that it does not deform significantly under the effect of its own weight. The solid hydroxylated material 1 may be a piece of corrugated cardboard formed from at least one sheet of fluted paper and at least one sheet of cardboard with a weight greater than 160 g / m. 2 .

[0072] In the method according to the invention shown in Figure 2, an applicator device 3 is chosen having an applicator surface provided with filiform elements 4 which are non-reactive with the fatty acid chlorides of a composition, called reactive composition 20, of at least one fatty acid chloride. Such an applicator device 3 is chosen which is adapted to be able to be subjected to a temperature between 160°C and 250°C without loss of its adsorbent and applicator functionalities. It may, for example, be an applicator device 3 whose applicator face is formed of filiform elements 4 of inorganic fibers or microfibers, such as glass fibers or microfibers or carbon fibers or microfibers, or of filiform elements 4 of aramid fibers or microfibers, such as aramid fibers or microfibers known under the brand name kevlar®.The applicator device 3 may be an applicator roller, an applicator pad or an applicator brush provided with the filiform elements 4. The applicator device 3 may have an applicator surface formed of oleophilic filiform elements 4 (having an affinity for fatty substances). Any type of suitable oleophilic material may be used. However, the applicator device 3 may have an applicator surface formed of 4 fi- elements. oleophobic liformes. In particular, these may be filiform elements 4 coated with a perfluorinated coating, in particular Teflon®. The applicator surface of the applicator device 3 is formed from a chemically stable material resistant to abrasion and temperature, in particular to said acylation temperature. Preferably, the filiform elements have a free end adapted to be able to cooperate with the surface of the solid material hydroxylated by brushing. The applicator device 3 may be a roller, in particular a roller of the “lacquer roller” type and adapted to be able to withstand said acylation temperature, without loss of its adsorbent and applicator properties. The filiform elements 4 are flexible and adapted to be able to be loaded with fatty acid chloride(s) and to be able to release at least a portion of the loaded fatty acid chloride(s), in particular by elastic deformation.The 4-filiform elements may have a length of between 1 mm and 100 mm or more. The filiform elements may have a cross-section with a diameter of between 1 μm and 1000 μm. The applicator device may be a lacquer roller whose applicator surface is formed of a velvet provided with filiform elements having an implantation density greater than 10 filiform elements per mm. 2 of applicator surface, in particular between 50 and 500 filiform elements per mm 2of applicator surface. The filiform elements are chosen to have - in particular during rotation of the applicator roller - a rigidity conferred due to the rotation of the applicator roller, which is sufficient to allow application of fatty acid chloride(s) over at least part of the thickness of the hydroxylated solid material, without damaging it. The filiform elements have a flexibility chosen so as not to damage the hydroxylated solid material, by contact.

[0073] In a method according to the invention, a composition, called a reactive composition, of at least one fatty acid chloride is chosen or prepared. At least one fatty acid chloride is chosen from the group formed by fatty acid chlorides of formula R-CO-C£ in which R is a hydrocarbon chain having a number of carbon atoms between 13 (inclusive) and 29 (inclusive), in particular between 15 (inclusive) and 29 (inclusive). At least one fatty acid chloride is chosen from the group formed by palmitic acid chloride (C10), stearic acid chloride (C18), arachidic acid chloride (C20) and behenic acid chloride (C22). At least one fatty acid chloride is behenic acid chloride (C22H4 OCC) whose vaporization temperature at atmospheric pressure is around 385°C.At least one fatty acid chloride is palmitic acid chloride (CiôEbiOCb) whose vaporization temperature at atmospheric pressure is around 330°C. At least one fatty acid chloride is chloride. stearic acid (CisHisOCC) whose vaporization temperature at atmospheric pressure is of the order of 350°C. Nothing prevents the use of a fatty acid chloride capable of being prepared by transchlorination of a fatty acid by a transchlorination agent such as, for example, acetyl chloride. The fatty acid chlorides chosen for the implementation of a method according to the invention are liquid at room temperature. In a method according to the invention, an impregnation 5 of the filiform elements 4 of the applicator device 3 is carried out with at least one liquid fatty acid chloride. This impregnation step 5 is carried out by bringing the filiform elements 4 and said reactive composition 20 into contact at room temperature, that is to say at a temperature reached without using means for regulating this temperature.However, nothing prevents the provision that the filiform elements 4 are during this impregnation 5 at a temperature higher than ambient temperature but also necessarily lower than or at most equal to said acylation temperature. The temperature of the filiform elements 4 is adapted to allow their loading with said reactive composition 20 essentially in the liquid state. Nothing prevents the provision that said reactive composition 20 is brought during this impregnation step 5 to a temperature higher than ambient temperature, but adapted, depending on the fatty acid chloride(s) used^), so that the fatty acid chloride(s) used are essentially in liquid form and capable of being impregnated in the liquid state on the filiform elements 4 of the applicator device 3. An applicator device 6 impregnated and loaded with said liquid reactive composition 20 is formed at the end of this impregnation step 5.

[0074] In a method according to the invention, a step 7 of heating said reactive composition 20 impregnated on the filiform elements 4 of the applicator device 3 is carried out and adapted so that said reactive composition 20 reaches said acylation temperature. This heating 7 is carried out by any suitable means. This may be radiative heating means (for example by radiation in the infrared range), inductive heating means, or convective heating means. It may also be heating means specific to the applicator device 3 and adapted to heat at least the filiform elements 4 and said reactive composition 20. At the end of this heating step 7, an applicator device 3 is formed provided with filiform elements 8 loaded with said reactive composition 20 brought to said acylation temperature.

[0075] In a method according to the invention, a step 9 of heating the solid material 1 is implemented so as to form a hot hydroxylated solid material 10 - in particular at said acylation temperature -, prior to a step 11 of applying the filiform elements 8 loaded with - and retaining - said corn- reactive position 20. Step 11 of application is carried out by rolling the applicator device 3 onto the hydroxylated solid material 1. Advantageously, the hot hydroxylated solid material 10 is at least partly dehydrated due to this heating 9. Furthermore, the fact that the hot hydroxylated solid material 10 is at said acylation temperature makes it possible to contribute to maintaining said reactive composition 20 at said acylation temperature, to promote chromatogenic acylation and to form the acylated solid material 12.

[0076] Surprisingly, the inventor found that the heating 7 of said reactive composition 20 adsorbed by impregnation in the filiform elements 4 of the applicator device 3 allows an application of fatty acid chloride to the hydroxylated solid material 1 and an acylation of this hydroxylated solid material 1 by acid chloride in the gaseous state. According to the invention, the application of said reactive composition 20 heated to said acylation temperature of between 160°C and 250°C does not lead to a loss of fatty acid chloride in the gaseous state by dissipation in the atmosphere surrounding the filiform elements 4,8. On the contrary, the filiform elements 4,8 seem to behave as a reservoir of fatty acid chloride - in particular in the gaseous state -, making it possible to release / form fatty acid chloride in the gaseous state in contact with the hydroxylated solid material 1 and acylate it.

[0077] The invention goes against the teaching provided by the prior art, which describes distributing the fatty acid chloride(s) in a preferentially liquid state and necessarily at low temperature in contact with the cold or hot solid material, then heating the cold hydroxylated solid material to said acylation temperature or maintaining the hot hydroxylated solid material at said acylation temperature. According to this teaching, the fatty acid chloride(s) essentially in the liquid state deposited^) in contact with the hydroxylated solid material constitute(s) a reservoir of fatty acid chloride(s) essentially in the liquid state placed in contact with the hydroxylated solid material. According to this teaching, fatty acid chloride(s) in the gaseous state is formed near the accessible hydroxyls of the hydroxylated solid material, due to the heating of the hydroxylated solid material to said acylation temperature.According to this teaching, the formation of fatty acid chloride(s) in the gaseous state near accessible hydroxyls of the hydroxylated solid material makes it possible to overcome the disadvantages of said boundary layer. That being said, the teaching provided by the prior art does not make it possible to solve the problem of the persistence on the hydroxylated solid material of quantities of fatty acid chloride(s) in the liquid state which have not been heated for a sufficiently long time to be vaporized and to be able to react in the gaseous state with the hydroxylated solid material, in particular due to the movement of the strip of hydroxylated solid material.

[0078] Of course, nothing prevents us from providing, in a variant not shown of a chromatogenic acylation process according to the invention implemented on an industrial scale, that the hydroxylated solid material is in the form of a strip of paper wound on itself in a reel, the paper being driven in scrolling between an upstream reel and a downstream device for rewinding a strip of acylated paper. In such a process implemented on an industrial scale, the paper has a scrolling speed of between 30 and 100 meters per minute. An example of a device suitable for implementing such a process is shown in Figure 4. In such a process, said reactive composition is applied at a fixed station to at least one main face of the strip of paper driven in scrolling. In such a process, the applicator device comprises an applicator roller having an applicator surface provided with filiform elements and arranged over the entire width (or width) of the strip of paper.The roller has an axis of rotation parallel to the plane of travel of the paper strip and not parallel - in particular orthogonal - to the direction of travel of this strip. The roller is placed vertically at a distance from the paper strip, so that the filiform elements brush against the paper strip as it travels, without damaging it. Advantageously, the roller may be of the type having an axial lumen for receiving said reactive composition and for distributing - assisted by a centrifugal force - said reactive composition conveyed along the filiform elements until it is brought into contact with the paper strip.

[0079] In certain advantageous embodiments, the roller is provided with means for heating said reactive composition to said acylation temperature. In these advantageous embodiments, the filiform elements forming the applicator surface of the roller act as an applicator reservoir for fatty acid chloride(s) in the gaseous state at said acylation temperature. In these advantageous embodiments, the volume in which the fatty acid chloride(s) are at saturated vapor pressure at said acylation temperature is limited to the free volume provided by the filiform elements of the roller heated to said acylation temperature. According to these advantageous embodiments, it is not necessary to provide a thermostatically controlled enclosure at said acylation temperature in which the partial pressure of the fatty acid chloride(s) is maintained at saturated vapor pressure throughout its entire volume.That being said, nothing prevents the provision of at least one fairing wall for the applicator roller(s) and for confining the fatty acid chloride(s) in gaseous state in contact with the paper strip.

[0080] In certain advantageous embodiments of a chromatogenic acylation method according to the invention implemented on an industrial scale, the roller having an axial lumen for receiving said reactive composition and centrifugal distribution of said reactive composition guided along the filiform elements until contact with the paper web, the roller - in particular the heating roller - is supplied with fatty acid chloride by supplying said reactive composition into the axial lumen of the roller. In these embodiments, the impregnation of the filiform elements is less partly ensured by the centrifugal stress produced due to the rotation of the roller, to which said reactive composition is subjected in the applicator roller.

[0081] In other embodiments, the applicator device may comprise, in addition to the roller, a device for distributing fatty acid chloride onto the roller. This may be a cylinder, called an anilox roller, for feeding the roller by licking the surface of said anilox roller with the filiform elements. Any type of anilox roller may be used. It may be used by adapting the dimensions of its cells and their surface density to the quantity of fatty acid chloride to be deposited on the applicator roller. Said anilox roller may have an angular rotation speed identical to or different from the rotation speed of the applicator roller. Said anilox roller may be supplied with liquid fatty acid chloride by a doctor blade chamber itself supplied - in particular continuously - with fatty acid chloride.

[0082] The roller can be rotated with an angular rotational speed chosen so that the free ends of the filiform elements are rotated with a linear speed of a value distinct from the value of the running speed of the paper strip. The linear speed of the free ends of the filiform elements and the running speed of the paper strip are not necessarily identical and can be adjusted so as to produce the desired touch. That being said, the roller can be rotated in a direction of rotation chosen so that the free ends of the filiform elements of the velvet are driven countercurrently or concurrently with the running of the paper strip.

[0083] In a chromatogenic acylation process according to the invention implemented on an industrial scale, nothing prevents the roller and the dispensing device from being arranged in a thermoregulated enclosure maintained at said acylation temperature.

[0084] In an advantageous variant, not shown, of a chromatogenic acylation process according to the invention implemented on an industrial scale, a flow of gaseous composition capable of being charged with hydrochloric acid in contact with the paper strip during acylation is formed so as to move the hydrochloric acid formed as a result of this acylation away from the paper strip.

[0085] A block diagram of a variant of a process according to the invention, for the chromatogenic acylation of a solid 1,2-material carrying hy- groups droxyls accessible to at least one fatty acid chloride in the gaseous state and capable of being able to react with this(these) fatty acid chloride(s) is represented in figure 3. In this variant represented, a plurality of phases 40,50,60 of acylation of a solid material 1,2 are carried out, each of the phases 40,50,60 comprising a step 11,24,34 of application of a reactive composition 20,21,22 on the solid material 1,2. The phases 40,50,60 of this plurality of phases can be implemented in a traditional manner successively on the same piece of a solid material 1, in particular a paper material. But the phases 40, 50, 60 of this plurality of phases can be implemented during an industrial process of chromatogenic acylation of a strip 2 of paper driven in scrolling between an upstream reel of the strip 2 of paper and a downstream device 36 for rewinding the strip 12, 25, 35 of acylated paper.During this implementation on an industrial scale, each reactive composition 20, 21, 22 is applied by means of a device 3, 15, 28 applicator of reactive composition(s) 20, 21, 22 respectively. The applicator devices 3, 15, 28 are arranged at a distance from each other, along a running zone of the strip 2, 12, 25, 35 of paper, extending in the thermoregulated enclosure 39. Each reactive composition 20, 21, 22 may be formed from a single fatty acid chloride or comprise a plurality of fatty acid chlorides. Advantageously, each reactive composition is free of any organic solvent. The reactive compositions 20, 21, 22 may comprise the same fatty acid chloride or different fatty acid chlorides and different fatty chain lengths.

[0086] The block diagram shown in Figure 3 also illustrates a method according to the invention implemented on an industrial scale, for the chromatogenic acylation of a strip 2 of a paper material 1 driven in scrolling between an upstream reel and a downstream device for rewinding a strip of acylated paper. In this industrial method, the strip 2 of paper is driven in scrolling by any means known to those skilled in the art, so that the paper of the strip 2 of paper successively passes, due to this scrolling, through a plurality of successive treatment zones.A first phase 40 of acylation of the paper of the paper strip 2 is carried out in an upstream zone (relative to the direction of travel from upstream to downstream of the paper strip) of the plurality of successive treatment zones, then a second phase 50 of acylation is carried out in an intermediate zone of this plurality of successive zones, then a third phase 60 of acylation is carried out in a downstream zone of this plurality of successive zones. For example, nothing prevents the provision of carrying out the first phase 40 of acylation at an acylation temperature T1, the second phase 50 of acylation at an acylation temperature T2 and the third phase 60 of acylation at an acylation temperature T3, T1 < T2 < T3.

[0087] During the first phase 40, the applicator device 3 has a surface applicator formed of filiform elements 4 which are not reactive with the fatty acid chlorides of said reactive composition 20. The applicator device 3 and the filiform elements 4 are adapted to be able to be placed without deterioration at a temperature between 160°C and 250°C and without loss of their applicator functionalities. In a method according to the invention implemented on an industrial scale, the applicator device 3 may be a roller arranged so that its axis of rotation on itself extends in a plane parallel to the plane of the strip 2 of paper driven in scrolling and not parallel - in particular orthogonal - to the direction of scrolling of this strip 2 of paper. The applicator device 3 is chosen and arranged so as not to damage the paper of the strip 2 of paper in scrolling. During the first phase 40, an impregnation 5 of the filiform elements 4 of the applicator device 3 with at least one liquid fatty acid chloride is carried out.This impregnation step 5 is carried out at low temperature (i.e. at a temperature lower than the envisaged acylation temperature) by bringing the filiform elements 4 forming the applicator surface of the applicator device 3 and said reactive composition 20 into contact at ambient temperature, i.e. at a temperature reached without using means for regulating this temperature. However, nothing prevents provision being made for the filiform elements 4 to be brought during this impregnation 5 to a temperature higher than ambient temperature but also necessarily lower than or at most equal to said acylation temperature.Nothing prevents the provision that said reactive composition 20 itself is brought during this impregnation step 5 to a temperature higher than ambient temperature, but adapted, depending on the fatty acid chloride(s) used^), so that the fatty acid chloride(s) used are essentially in liquid form and can be loaded in the liquid state onto the filiform elements 4 of the applicator device 3. An applicator device 6 loaded with said liquid reactive composition 20 is obtained at the end of this impregnation step 5.

[0088] In a method according to the invention, a step 7 of heating said reactive composition 20 adsorbed on the filiform elements 4 of the applicator device 3 is carried out, this heating step 7 being adapted so that said reactive composition 20 reaches an acylation temperature T1. This heating 7 is carried out by any suitable means. Following this heating step 7, an applicator device 3 is formed, provided with filiform elements 8 loaded with said reactive composition 20 at said acylation temperature T1.

[0089] In a method according to the invention, a step 9 of heating the paper of the strip 2 of paper driven in scrolling is implemented so as to form a hot paper 10 at said acylation temperature T1, prior to a step 11 of applying the hot filiform elements 8 retaining said reactive composition 20, by rolling the applicator device 3 on the hot paper 10 of the strip 2 of paper. Furthermore, the fact that the hot paper 10 is at said acylation temperature Tl makes it possible to contribute to maintaining said reactive composition 20 at said acylation temperature Tl, to promote chromatogenic acylation and to form the acylated solid material 12.

[0090] During a second phase 50 of chromatogenic acylation, an applicator device 15 is used having an applicator surface formed of filiform elements 16 which are non-reactive with the fatty acid chlorides of a second reactive composition 21. The applicator device 15 and the filiform elements 16 are adapted to be able to be placed, without deterioration, at a temperature between 160°C and 250°C and without loss of the applicator functionalities. In a method according to the invention implemented on an industrial scale, the device 15 applicator can be a roller with a rotation axis extending in a plane parallel to the plane of the strip 2 of paper driven in scrolling and not parallel - in particular orthogonal - to the direction of scrolling of the paper. The applicator device 15 is chosen and arranged so as not to damage the paper 1, 2, 14 in scrolling. During the second phase 50, an impregnation 17 of the elements 16 filiform elements of the applicator device 15 with at least one liquid fatty acid chloride is carried out. This impregnation 17 is carried out at a temperature lower than the envisaged acylation temperature T2, by bringing the filiform elements 16 into contact with said reactive composition 21 at room temperature, that is to say at a temperature reached without using means for regulating this temperature. However, nothing prevents provision being made for the filiform elements 16 to be at a temperature higher than room temperature during this impregnation 17. This being the case, the filiform elements 16 are at a temperature necessarily lower than or at most equal to said acylation temperature T2.Nothing prevents provision being made for said reactive composition 21 to be brought during this impregnation step 17 to a temperature above ambient temperature, but adapted, depending on the fatty acid chloride(s) used, so that the fatty acid chloride(s) used are essentially in liquid form and can be loaded in the liquid state onto the filiform elements 16. An applicator device 18 loaded with said liquid reactive composition 21 is formed at the end of this impregnation step 17. A step 19 of heating said reactive composition 21 adsorbed on the filiform elements 16 of the applicator device 15 is then carried out and adapted so that said reactive composition 21 reaches the acylation temperature T2. This heating 19 is carried out by any appropriate means.From this heating step 19, an applicator device is formed, the filiform elements 23 of which, loaded with said reactive composition 21, are brought to said acylation temperature T2.

[0091] A step 13 of heating the paper of the strip 12 of paper driven in scrolling is implemented so as to form a hot paper 14 at said acylation temperature T2, prior to a step 24 of applying said reactive composition 21 on the hot paper 14, by rolling the applicator device 15 on the paper 14 and bringing the filiform elements 23 into contact with the hot paper 14. Furthermore, the fact that the paper 14 is at said acylation temperature T2 makes it possible to contribute to maintaining said reactive composition 21 at said acylation temperature T2, to promote chromatogenic acylation and to form an acylated paper 25 carrying acyl groups of the first and second reactive compositions 20, 21.

[0092] In the embodiment shown, during a third phase 60, an applicator device 28 is used having an applicator surface formed of filiform elements 29 which are not reactive with the fatty acid chlorides of a reactive composition 22. The applicator device 28 and the filiform elements 29 are adapted to be able to be placed without deterioration at a temperature T3 of between 160°C and 250°C and without loss of the applicator functionalities. In a method according to the invention implemented on an industrial scale, the applicator device 28 is preferably an applicator roller 28 with an axis of rotation on itself extending in a plane parallel to the plane of the paper of the strip 25,2 of paper driven in scrolling and not parallel - in particular orthogonal - to the direction of scrolling of the paper. The applicator device 28 is chosen and arranged so as not to damage the paper of the strip 2.25 as it unwinds.During the second acylation phase 60, an impregnation 30 of the filiform elements 29 with at least one liquid fatty acid chloride is carried out. This impregnation 30 is carried out at a temperature below a envisaged acylation temperature T3, by bringing the filiform elements 29 of the applicator device 28 into contact with said reactive composition 22 at ambient temperature, that is to say at a temperature reached without using means for regulating this temperature. However, nothing prevents provision being made for the filiform elements 29 to be at a temperature above ambient temperature during this impregnation 30 but also preferably below said acylation temperature T3.Nothing prevents the provision that said reactive composition 22 is brought during this impregnation step 30 to a temperature higher than ambient temperature, but adapted, depending on the fatty acid chloride(s) used, so that the fatty acid chloride(s) used^) are essentially in liquid form and chargeable by adsorption in the liquid state on the filiform elements 29 of the applicator device 28. An applicator device 31 loaded with said liquid reactive composition 22 is formed at the end of this impregnation step 30. A step 32 of heating said reactive composition 22 adsorbed / impregnated in the filiform elements 29 of the applicator device 28 and adapted so that said reactive composition 22 reaches the acylation temperature T3 is then carried out. This heating 32 is carried out by any appropriate means. At the end of. this heating step 32, filiform elements 33 loaded by impregnation with said reactive composition 22 brought to said acylation temperature T3.

[0093] A step 26 of heating the paper of the strip 2, 25 of paper driven in scrolling is implemented so as to form a hot paper 27 at said acylation temperature T3, prior to a step 34 of applying the filiform elements 33 of the applicator device 28 retaining said reactive composition 22, by rolling the applicator device 28 on the paper 27. Furthermore, the fact that the paper 27 is at said acylation temperature T3 makes it possible to contribute to maintaining said reactive composition 22 at said acylation temperature T3, to promote chromatogenic acylation and to form an acylated solid material 35 bearing acyl groups of the first, second and third reactive compositions 20, 21, 22. Other subsequent acylation phases may be provided.

[0094] In an embodiment not shown, nothing prevents the provision of carrying out a final phase of extraction of fatty acid chloride likely to be present in excess on the moving paper strip. To do this, a recovery device comprising an extractor roller, in particular a lacquer roller having a recovery surface formed of a velvet, can be applied to the paper strip to collect in return fatty acid chloride in the liquid state from the paper.

[0095] An example of an acylation device 100 that can be used for implementing a method according to the invention is shown in Figure 4. The acylation device 100 comprises an upstream reel 66 for a strip 2 of paper to be acylated and a downstream device 36 for rewinding a strip 35 of acylated paper. The acylation device 100 is provided with means 37 for guiding the strip 2 of paper as it moves between the upstream reel 66 and the downstream reel 36. The guiding means 37 comprise a plurality of rollers for guiding the strip 2, 10, 12, 25, 35 of paper driven as it moves, positioned so as to guide the strip 2, 10, 12, 25, 35 of paper as it moves in a thermoregulated enclosure 39 of the acylation device 100.The thermo-regulated and, where appropriate, compartmentalized enclosure 39 has a first upstream zone 41 (along the direction 42 of travel of the strip 2 of paper 1) for the entry of the paper 1 of the strip into the first upstream zone 41 and into the thermo-regulated enclosure 39. This first upstream zone 41 is provided with at least one heating roller 38 and means for guiding the strip 2 of paper, adapted to heat the strip 2 of paper to a temperature allowing its dehydration, at least partially during its travel and prior to its acylation. The thermo-regulated enclosure 39 has, extending downstream of the first upstream heating zone 41, a first acylation zone 43 adapted to be able to be crossed by the strip 2 of paper in travel. The first zone 43. acylation zone may be provided with means (not shown) for heating and / or maintaining the atmosphere of this first acylation zone 43 at a chromatogenic acylation temperature T1. It also comprises a device 45 for dispensing a reactive composition 20 of at least one - in particular a single - fatty acid chloride on the surface of the strip 2 of paper. The dispensing device 45 comprises a support roller 44 and an applicator roller 3 having an applicator surface formed of filiform elements 4, in particular filiform elements 4 forming a velvet. The applicator roller 3 is adapted to be able to be rotated on itself so that the filiform elements 4 sweep by touching the surface of the strip 2, 10 of paper driven in scrolling. The support roller 44 and the filiform elements 4 of the applicator roller 3 cooperate to guide the strip 2, 10 of paper into contact with the filiform elements 4 of the applicator roller 3.

[0096] The thermoregulated enclosure 39 has, extending downstream of the first acylation zone 43, a second acylation zone 48 adapted to be able to be crossed by the strip 2 of paper 12 driven in scrolling and treated in the first acylation zone 43. The second acylation zone 48 can be provided with means (not shown) for heating and / or maintaining the atmosphere of this second acylation zone 48 at a chromatogenic acylation temperature T2. It also comprises a device 51 for dispensing a reactive composition 21 of at least one - in particular a single - fatty acid chloride.The dispensing device 51 comprises a support roller 49, an applicator roller 15 having an applicator surface formed of filiform elements 16, in particular filiform elements 16 forming a velvet, and adapted to be able to be driven in rotation so that the filiform elements 16 sweep by touching the surface of the strip 2 of paper 12 driven in scrolling. The support roller 49 and the applicator roller 15 cooperate to guide the strip 2 of paper 12 by applying it in contact with the filiform elements 16 of the applicator roller 15.

[0097] The thermoregulated enclosure 39 has, extending downstream of the second acylation zone 48, a third acylation zone 54 adapted to be able to be crossed by the moving strip 2 of paper treated in the second acylation zone 48. The third acylation zone 54 may be provided with means (not shown) for heating and / or maintaining the atmosphere of this third acylation zone 54 at a chromatogenic acylation temperature T3. It also comprises a device 56 for dispensing a reactive composition 22 of at least one - in particular a single - fatty acid chloride. The dispensing device 56 comprises a support roller 55 and an applicator roller 28 having an applicator surface formed of filiform elements 29, in particular filiform elements 29 forming a velvet, and adapted to be able to be en- dragged in rotation so that the filiform elements 29 lightly sweep the surface of the strip 2 of paper driven in scrolling. The support roller 55 and the applicator roller 28 cooperate to guide the strip 2 of paper by applying one of the faces of the strip 2 of paper in contact with the applicator roller 28.

[0098] In certain advantageous embodiments, at least one - in particular each - of the applicator rollers 3, 15, 28 is provided with means for heating said corresponding reactive composition 20, 21, 22 to the acylation temperature T1, T2, T3. In these embodiments, the first, second and third acylation zones 43, 48, 54 of the thermoregulated and / or compartmentalized enclosure 39 are not necessarily each heated to said corresponding acylation temperature T1, T2, T3. In addition, at least one - in particular each - of the applicator rollers 3, 15, 28 advantageously has an axial lumen for centrifugal supply - in particular continuously - of the filiform elements 4, 16, 29 with reactive compositions 20, 21, 22.

[0099] Nothing also prevents provision being made for at least one - in particular each - of the support rollers 44, 49, 55 to be a heating roller adapted to contribute to the heating of the strip 2 of paper to said acylation temperature.

[0100] In certain other embodiments not shown, at least one - in particular each - of the distributor devices 45, 51, 56 may comprise a cylinder, called an anilox roll, for supplying the applicator roll 3, 15, 28 with a reactive composition 20, 21, 22. Said anilox roll is arranged to be able to be touched tangentially by the corresponding applicator roll 3, 15, 28. In these embodiments, the temperature of said anilox roll and of the reactive composition 20, 21, 22 presented by said corresponding anilox roll are substantially at the same temperature as the applicator roll 3, 15, 28. Said anilox roll may be supplied with liquid fatty acid chloride by means of a doctor blade chamber itself supplied - in particular continuously - with fatty acid chloride.In these embodiments, the doctor blade chamber forms a wall covering said anilox roller opposite its peripheral surface, with the exception of an open strip allowing contact between said anilox roller and the applicator roller 3, 15, 28.

[0101] The thermoregulated enclosure 39 has, extending downstream of the third acylation zone 54, a zone 59 for extraction and return exchange of fatty acid chloride likely to be present in excess on the moving paper strip. The extraction zone 59 is provided with a support roller 61 arranged to be able to cooperate with an extractor roller 62 having a recovery surface formed of filiform elements 63 and guide the moving paper strip 35. The recovery surface of the extractor roller 62 may be a velvet provided with filiform elements 63 capable of being loaded with excess fatty acid chloride(s) on the surface of the paper strip 35. Advantageously, a flow 64 of gaseous composition - in particular a flow of atmospheric air - heated to a temperature higher than said acylation temperature - in particular between said acylation temperature and the vaporization temperature of at least one - in particular of each - fatty acid chloride of said reactive composition -, is applied in contact with the strip 2 of paper so as to entrain residual fatty acid chloride, vaporized under the effect of the flow 64 of gaseous composition. The flow 64 of gaseous composition loaded with fatty acid chloride is entrained successively in acylation zones 54, 48, 43, in countercurrent - from downstream to upstream - of the direction of travel of the strip 2 of paper and also allows entrainment of the gaseous hydrochloric acid formed due to the acylation reaction in the thermoregulated enclosure 39.

[0102] In some embodiments, the extractor roller 62 is heated to a temperature—particularly a temperature between 250°C and 400°C—that promotes the vaporization of fatty acid chloride(s). In other embodiments, the flow of gaseous composition heated to the vaporization temperature is applied to the filiform elements of the extractor roller.

[0103] In certain embodiments, the gaseous atmosphere of the thermoregulated and / or compartmentalized enclosure 39 and / or the gaseous atmosphere extending into the lumen of at least one applicator roller 3, 15, 28 is depleted in gaseous oxygen. In these embodiments, a flow of at least one inert gas is introduced into the thermoregulated and / or compartmentalized enclosure 39 and / or into the gaseous atmosphere extending into the lumen of at least one applicator roller 3, 15, 28.

[0104] EXAMPLE 1 - Conditions of application An applicator device is made using glass microfibers bonded together to form an applicator pad or brush. The glass microfibers are chosen to be resistant to temperatures between 160°C and 250°C. They are advantageously neutral with respect to the fatty acid chlorides used. The applicator brush is loaded by briefly contacting the applicator brush with a piece of fabric measuring 100 mm x 100 mm of microfibers impregnated with 4 mL of undiluted liquid fatty acid chloride. It has been shown that this qualitative approach makes it possible to deposit on a solid material by contact of the brush on the solid material held for a fraction of a second, the minimum quantity of fatty acid chloride allowing to confer a hydrophobicity of the treated paper material which is acceptable after development of the acylation reaction.

[0105] The applicator brush thus loaded with fatty acid chloride is used to apply fatty acid chloride to a hydroxylated solid material. The applicator brush can be applied to the paper material with a contact time of the tip of the applicator brush and the hydroxylated solid material of the order of magnitude of 1 / 1 O eme second and so that the tip of the microfiber brush deforms on contact, generating intimate physical contact between the microfibers of the brush and the surface of the paper material, promoting the transfer of fatty acid chloride.

[0106] That being said, it is possible to apply the fatty acid chloride by sliding the tip of the applicator brush over the surface of the paper material, like a paint. The application of fatty acid chloride by means of a brush thus made makes it possible to mimic an application of fatty acid chloride on a paper driven in scrolling as it can be carried out by means of a lacquer roller provided with filiform elements, favoring an instantaneous application of reagent rather than a continuous application.

[0107] EXAMPLE 2 - Application conditions - Variable temperature of the applicator brush - Paper material at room temperature Example 2 describes the application of a fatty acid chloride using a hot acid chloride applicator brush to a paper material at room temperature. Palmitic acid chloride (CisEEi-CO-Cf) or stearic acid chloride (CnEEs-CO-Cf) is applied to a piece of blotting paper (Canson, 125 g / m 2) by means of an applicator brush as described in Example 1 and maintained after its loading with fatty acid chloride at the acylation temperature in a thermostatically controlled oven. The applicator brush after loading is wrapped in a sheet of aluminum foil to maintain its temperature and placed in the oven thermostatically controlled at the acylation temperature. Fatty acid chloride at the acylation temperature is applied by point contact, as described in Example 1, of the hot applicator brush on the blotting paper at room temperature after removal of the sheet of aluminum foil. After this contact, the blotting paper is placed for a few minutes in an oven at a temperature of 180°C to allow the acylation reaction to develop, then cooled to room temperature. The hydrophobicity of the treated blotting paper is evaluated by immersion in distilled water.The hydrophobic character of the blotting paper obtained makes it possible to evaluate the effectiveness of the acylation. The hydrophobic character of the blotting paper is evaluated by measuring the dimensions of the hydrophobic stain formed as well as its intensity, reflecting its resistance to humidification.

[0108] It is observed that the application of the reagent by the applicator brush maintained at room temperature produces a limited hydrophobic stain corresponding to the deposition zone of the fatty acid chloride. When the temperature of the applicator brush increases, the observed stains increase in size and intensity of hydrophobicity up to a temperature limit value beyond which the hydrophobicity decreases. This limit value is of the order of 200°C for palmitic acid chloride (C10) and of the order of 220°C for stearic acid chloride (C1s).

[0109] These results indicate that the efficiency of the acylation and the quality of the grafting obtained depend on the temperature of the applicator brush and its filiform elements, and on the temperature of the reactive composition comprising the fatty acid chloride retained by the filiform elements. Unexpectedly, heating the fatty acid chloride retained by the applicator brush, which necessarily promotes a shift in the liquid / vapor equilibrium of the fatty acid chloride towards the vapor state, does not, in reality, lead to a loss of the fatty acid chloride in the gaseous state by diffusion into the atmosphere, but allows grafting of the fatty acid chloride in the gaseous state onto the paper material without leaving substantially any liquid fatty acid chloride remaining on the paper material.

[0110] The invention therefore goes against a prejudice of the state of the art according to which fatty acid chloride must necessarily be deposited in an essentially liquid state by printing on a moving paper strip to allow the acylation of this paper strip by heating the fatty acid chloride deposited on the paper strip.

[0111] EXAMPLE 3 - Application Conditions - Hot Applicator Brush - Variable Temperature Paper Material A fatty acid chloride (C16 palmitic acid or Cis stearic acid) is applied to a paper material heated to a temperature above room temperature using a hot applicator brush impregnated with the corresponding acid chloride. The applicator brush impregnated with palmitic acid chloride (C16) is maintained at a temperature of 200°C and the applicator brush impregnated with stearic acid chloride (C16) is maintained at a temperature of 220°C as described in Example 1. Fatty acid chloride (palmitic or stearic) is applied to a piece of blotting paper (Canson, 125 g / m 2) placed in an oven at the acylation temperature. Immediately after the application of the fatty acid chloride, the piece of blotting paper that has been the subject of this application is covered with a second piece of blotting paper as a piece of developer paper. The superposition of the two "emitting / developing" pieces is kept in the oven for a few minutes at the acylation temperature. The hydrophobicity conferred on the developer piece is indicative of an excess of fatty acid chloride on the piece of emitting paper, not having reacted with this piece of emitting paper at the acylation temperature.

[0112] The combination of hot deposition of palmitic acid chloride (CI0) using an applicator brush heated to a temperature of 200°C on a piece of emitting blotting paper heated to a temperature of 140°C, 170°C or 200°C makes it possible to demonstrate that acylation is promoted by blotting paper at a higher temperature, in particular at a temperature close to (or equal to) the temperature of the applicator brush and the fatty acid chloride associated with the brush. The revealing part superimposed on the emitting part itself heated to 140°C presents a significant hydrophobicity. The hydrophobicity of the revealing part decreases when the emitting part has been heated to a temperature of 170°C, to be almost undetectable when the emitting part has been heated to a temperature of 200°C.

[0113] The combination of hot deposition of stearic acid chloride (Cis) using an applicator brush heated to a temperature of 220°C on a piece of emitting blotting paper itself heated to a temperature of 160°C, 190°C or 220°C makes it possible to demonstrate that acylation is promoted by blotting paper at a higher temperature, in particular at a temperature equal to the temperature of the applicator brush and the fatty acid chloride associated with the brush. The developer piece superimposed on the emitting piece itself heated to 160°C exhibits significant hydrophobicity. The hydrophobicity of the developer piece decreases when the emitting piece has been heated to a temperature of 190°C, to be almost undetectable when the emitting piece has been heated to a temperature of 220°C.

[0114] The presence and amount of residual free acid chloride on the emitting piece of paper is highly dependent on the temperature of the applicator brush and the temperature of the fatty acid chloride associated with the brush and the temperature of the piece of paper on which the fatty acid chloride is deposited.

[0115] The combination of hot deposition of fatty acid chloride by means of an applicator brush heated to the acylation temperature of between 160°C and 220°C on a piece of paper material itself brought to the acylation temperature makes it possible to obtain optimal acylation of the paper material for a reduced treatment time - in particular almost complete in 1 / 10 of a second - and compatible with on-the-fly treatment of a paper web driven in unwinding. Such optimal acylation can of course only be obtained by controlling and adjusting the quantity of fatty acid chloride deposited on the paper material, since a deposition of a quantity of fatty acid chloride greater than the narrow stoichiometric quantity of accessible hydroxyls on the paper material will leave a residue of fatty acid chloride on the surface of the paper material.

[0116] EXAMPLE 4 - Application conditions - Hot applicator brush - Hot paper material - Successive deposits A succession of hot deposits of a fatty acid chloride are made on the same area of ​​a piece of blotting paper, called the emitting piece, each deposit in the succession of deposits being carried out as described in Example 3 using a hot applicator brush loaded with fatty acid chloride. After each hot deposit in the succession of deposits, a piece of developer paper is superimposed on the emitting piece, the superposition of the two pieces "emitting / developing" being kept in an oven for a few minutes at the acylation temperature. The hydrophobicity conferred on the developing piece is indicative of an excess of fatty acid chloride on the emitting piece of paper, not having reacted with this emitting piece of paper at the acylation temperature. The hydrophobicity of the emitting piece increases with the number of deposits. The hydrophobicity of the developing piece corresponding to the first two deposits remains low but increases with the third deposit. It is clear from this example that acylation takes place during the first two deposits without significant release of fatty acid chloride from the emitting piece, only the third deposit being accompanied by a significant release of fatty acid chloride leading to acylation of the third developing sheet.For greater efficiency of the chromatogenic acylation reaction, it is desirable to carry out acylation at a high temperature compatible with the thermal resistance of the paper material and to carry out several successive deposits of reduced quantities of fatty acid chloride. This is all the more so since the grafting of the fatty acid chloride onto the paper material and its immobilization has the effect of shifting, by mass effect, the liquid / vapor equilibrium of the fatty acid chloride towards the formation of vaporous fatty acid chloride and its grafting onto the paper material. The paper material and the surface hydroxyl groups behave as a specific “pump” of the vaporous fatty acid chloride which will tend to lower the concentration of the vaporous fatty acid chloride at the substrate level and promote the diffusion of the reagent from the applicator brush towards the paper material.

[0117] The efficiency of the chromatogenic acylation reaction is defined by evaluating the hydrophobicity of the acylated solid material by measuring the contact angle formed between the principal plane of the acylated solid material and a drop of pure water deposited on the surface of the acylated solid material. Typically, a contact angle value of an acylated solid material is between 90° and 150°, the contact angle value of 150° corresponding to a particularly hydrophobic and water-repellent material. The quality of the acylation is also defined by measuring the time during which the contact angle value between 90° and 150° is maintained at room temperature and by the water pocket test. The water pocket test can only be carried out with a solid material in the form of a substantially square flexible sheet allowing the corners to be brought together to form a water pocket. The watertightness of this water pocket is analyzed by monitoring water loss (taking into account evaporation).

[0118] Hydrophobicity can also be assessed by observing water repellency. 1 mL of distilled water is placed on the surface of the solid material and it is observed whether the resulting water droplet rolls on the surface, sticking to the surface of the solid material or not. Satisfactory water repellency corresponds to a contact angle of approximately 150°.

[0119] The invention may be the subject of numerous variants and applications other than those described above. In particular, it goes without saying that unless otherwise indicated the different structural and functional characteristics of each of the embodiments described above should not be considered as combined and / or closely and / or inextricably linked to each other, but on the contrary as simple juxtapositions. Furthermore, the structural and / or functional characteristics of the different embodiments described above may be the subject in whole or in part of any different juxtaposition or any different combination.

Claims

Demands

1. A chromatogenic acylation process for a solid material (1,2) bearing hydroxyl groups accessible to at least one fatty acid chloride in the gaseous state and capable of reacting with said fatty acid chloride(s) in the gaseous state, wherein: at least one composition, referred to as reactive composition (20,21,22), of at least one fatty acid chloride is applied at least to the surface of said hydroxylated solid material (1,2) by means of at least one applicator device (3,15,28) having an applicator surface formed of filamentous elements (4,16,29) that are non-reactive with said reactive composition (20,21,22) and capable of releasing said reactive composition (20,21,22) at least onto the surface of said hydroxylated solid material (1,2) by contact of the filamentous elements (4,16,29) and the solid material (1,2) hydroxylated, characterized in that said reactive composition (20,21,22) applied by the applicator device (3,15,28) at least on the surface of said material (1,2) the hydroxylated solid is, at the time of its application, at a temperature, called the acylation temperature, lower than the vaporization temperature of at least one fatty acid chloride of said reactive composition (20,21,22) and chosen to allow acylation of said solid material (1,2) by reaction of at least one fatty acid chloride in the gaseous state of said reactive composition (20,21,22) on at least one of the hydroxyl groups of said solid material (1,2), said acylation temperature being between 160°C and 250°C.

2. A method according to claim 1, characterized in that at least a portion of the applicator surface of the applicator device (3,15,28) is in contact with a portion of the surface of the hydroxylated solid material (1,2), at least this portion of the surface of the hydroxylated solid material (1,2) is at said acylation temperature when said reactive composition (20,21,22) is applied to the hydroxylated solid material (1,2).

3. A method according to any one of claims 1 or 2, characterized in that the filiform elements (4,16,29) forming the applicator surface are at said acylation temperature when said reactive composition (20,21,22) is applied to the hydroxylated solid material (1,2).

4. A method according to any one of claims 1 to 3, characterized in that said reactive composition (20, 21, 22) is applied at least to the surface of said hydroxylated solid material (1, 2), in an enclosure (39) thermo regulated adapted to maintain said reactive composition (20,21,22) released by the applicator device (3,15,28) at said acylation temperature.

5. A process according to any one of claims 1 to 4, characterized in that it comprises at least one step of redistribution of fatty acid chloride(s) deposited on the hydroxylated solid material, without further input of said reactive composition (20,21,22), the redistribution step being carried out by means of at least one distributing device having an applicator surface formed of non-reactive filament elements with the fatty acid chlorides of said reactive composition and capable of being charged with fatty acid chlorides deposited on the hydroxylated solid material, by contact of the filament elements of the distributing device and the hydroxylated solid material (1,2) and to release at least a part of the charged fatty acids, by contact of the filament elements and the hydroxylated solid material (1,2), the distributing device being at a temperature between 160°C and 250°C.

6. A process according to any one of claims 1 to 5, characterized in that at least one reactive composition (20,21,22) comprises at least one fatty acid chloride selected from the group consisting of palmitic acid chloride (Cl 6), stearic acid chloride (Cl 8), arachidic acid chloride (C20) and behenic acid chloride (C22).

7. A method according to any one of claims 1 to 6, characterized in that the (1,2) hydroxylated solid material is a paper material.

8. A method according to any one of claims 1 to 7, characterized in that the hydroxylated solid material (1, 2) is formed from a strip (2, 10, 12, 25) of paper conveyed in a direction (42) of conveyance parallel to the largest dimension of the strip (2.10.12.25.35), between a reel (66) upstream of said belt (2.10.12.25.35) of paper and a winder (36) downstream of a strip (12.25.35) of acylated paper.

9. Method according to claim 8, characterized in that at least one reactive composition (20,21,22) is applied at fixed station(s) at least on one main face of the (2,10,12,25) paper strip being conveyed.

10. A method according to any one of claims 8 or 9, characterized in that at least one applicator device (3, 15, 28) is an axle roller of rotation parallel to the plane of the paper strip (2,10,12,25) and not parallel to the direction (42) of scrolling.

11. A method according to any one of claims 8 to 10, characterized in that it comprises at least two applications of reactive composition(s) (20,21,22) at fixed positions on the conveyed paper web, each reactive composition(s) (20,21,22) being at said acylation temperature at the time of its application.

12. A method according to any one of claims 8 to 11, characterized in that the solid material (1,2) is a paper material coated with polyvinyl alcohol.

13. A method according to any one of claims 8 to 12, characterized in that the filiform elements (4,16,29) of at least one applicator roller (3,15,28) are fed by centrifugal diffusion of said reactive composition (20,21,22) from an axial light of this applicator roller (3,15,28) driven in rotation on itself.

14. Method according to claim 13, characterized in that said reactive composition (20,21,22) is introduced into the axial light of the applicator roller (3,15,28) by means of a distribution ramp of said reactive composition (20,21,22) over the length of the axial light, the distribution ramp extending over substantially the entire length of the axial light.

15. A method according to any one of claims 8 to 14, characterized in that at least one applicator roller (3,15,28) is provided with means for heating said reactive composition (20,21,22) to said acylation temperature.

16. A method according to any one of claims 8 to 15, characterized in that a sample of fatty acid chloride(s) from the paper strip (12, 25, 35) is taken by means of a recovery device (62) having a rotating recovery surface (63) provided with filamentous elements, non-reactive with said reactive composition and capable of: becoming loaded with fatty acid chloride(s) by contact between the recovery surface (63) and the paper strip (12, 25, 35), and - release fatty acid chloride(s) by applying a flow of gaseous composition (64) heated to a temperature above said acylation temperature, the flow of gaseous composition (64) being applied in contact with the recovery surface (63).

17. A method according to any one of claims 1 to 16, characterized in that the wire-like elements (4, 16, 29) are formed of at least one material chosen from the group consisting of aramid fibers and microfibers and inorganic fibers and microfibers.

18. A method according to any one of claims 1 to 17, characterized in that at least a portion of gaseous hydrochloric acid formed as a result of chromatogenic acylation is carried along by a flow of a gaseous composition circulating in contact with the solid material (1,2), at said acylation temperature.

19. A process according to any one of claims 1 to 18, characterized in that said reactive composition (20,21,22) is free of any solvent medium.

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