Method for acylation of hydroxylated solid materials

Abstract

The invention relates to a method for acylation of a solid material (3, 9) having reactive hydroxyl groups, wherein: at least one fatty acid chloride (1) is distributed at least on the surface of the solid material (3, 9) by means of a distribution device (2) having an application surface; the at least one fatty acid chloride (1) distributed at least on the surface of the solid material (3, 9) is heated to a temperature below the vaporization temperature of the at least one fatty acid chloride (1), the so-called acylation temperature, in order to allow acylation of the solid material (3, 9); and; a gaseous composition stream (6) is heated at the acylation temperature. ) is directed onto the solid material (3, 9) in order to entrain at least some of the gaseous hydrochloric acid (7) produced by the acylation reaction; characterized in that the application surface of the distributor device (2) is a pile provided with thread-like pile elements capable of: o filling at least one fatty acid chloride (1) by contact with at least one fatty acid chloride, and; o releasing at least one fatty acid chloride by contacting the thread-like elements of the pile with the solid material (3, 9); performing the distribution step (12, 14) so ​​that the at least one fatty acid chloride is applied to the solid material (3, 9) at a rate of 20 mg / m 2 and 1 mg / m 2 The amount between the surface areas of the solid materials (3, 9) is distributed over the solid materials (3, 9).

Description

[0001] The present invention relates to an improved method for acylation of solid materials carrying hydroxyl groups (-OH), called reactive hydroxyl groups, which are accessible and capable of reacting with fatty acid chlorides in the gaseous state, by chromogenic synthesis. The present invention therefore relates to such an improved method which makes it possible to transform such solid materials, which are hydrophilic due to said reactive hydroxyl groups, in particular due to said surface reactive hydroxyl groups, into hydrophobic materials which substantially retain the porosity of the hydrophilic solid material. The present invention relates to an improved method for acylation of such solid materials in the form of porous or non-porous sheets, in particular flat sheets. The present invention relates in particular to an improved method for acylation of such solid materials in the form of paper, which are mainly composed of cellulose fibers permeable to gases and permeable to aqueous liquids, thereby obtaining acylated paper, which is permeable to gases and has a permeability to aqueous liquids that is significantly reduced compared to the initial paper. Therefore, the present invention more particularly relates to a method for acylation of paper, paper web or paper strip and waterproofing against aqueous liquid compositions. In particular, the present invention relates to an improved acylation process which enables the production of an acylated paper which is permeable to air and impermeable to human liquid aqueous excretions of the oral cavity, nasal cavity and / or eye, and in particular to such aqueous excretions as carriers of pathogenic microorganisms, and in particular of infectious viral particles. More specifically, the present invention relates to a process for acylation of a paper material permeable to gas and permeable to aqueous liquids, in order to obtain an acylated paper material for purification by filtering a respiratory air stream. The present invention also extends to such an acylated paper material obtainable by the process according to the invention.

[0002] The present invention relates to a method for acylation of solid materials, in particular flexible materials which can extend at least partially into a plane, which carry such reactive hydroxyl groups and can be used on a manual scale, that is to say for short-term individual preparations.

[0003] However, the present invention relates to a method for acylation of a solid material, in particular a flexible material capable of extending at least partially into a plane, which solid material carries such reactive hydroxyl groups and which can be used on an industrial scale, i.e. for acylation of a web (or strip) of solid material carrying such reactive hydroxyl groups, which is moved along the main axis of the material web.

[0004] A chromogenic acylation reaction of solid materials with such reactive hydroxyl groups is known, wherein a gaseous long-chain fatty acid chloride reacts with the surface reactive hydroxyl groups of the solid material and forms an ester group between the solid material and the hydrocarbon-based fatty chain (R) of the fatty acid chloride according to the following reaction formula (I):

[0005]

[0006] In particular, it is known to apply a color development reaction to a cellulosic material including a cellulosic fiber having such reactive hydroxyl groups. At least a portion of such reactive hydroxyl groups of the cellulosic fiber are bonded to a hydrocarbon-based fatty chain (R) in a covalent ester bond, making it possible to increase the hydrophobicity of the cellulosic fiber and render the cellulosic material, such as paper, acylated and substantially impermeable to water.

[0007] Under saturated partial pressure, a color reaction occurs between the solid material with such reactive hydroxyl groups and the gaseous fatty acid chloride. This makes it possible to suspend the use of any organic solvent, the acyl chloride being reactive in the gaseous state. It occurs by moderately heating the fatty acid chloride at a temperature below its boiling point under atmospheric pressure. It also makes it possible to suspend the use of the catalyst that must inevitably be removed at the end of the reaction. In addition, since the gaseous hydrochloric acid (HCl) formed is entrained by the hot air stream applied to the solid material, the color reaction is therefore facilitated. This entrainment of the gaseous hydrochloric acid makes it possible to limit - or even completely prevent - the hydrolysis of the formed ester, and especially to shift the reaction equilibrium in the direction of acylation.

[0008] WO99 / 08784 describes a method for acylation of such solid materials with such reactive hydroxyl groups used on a laboratory scale. In this method, a piece of "Whatmanno.2" filter paper is impregnated with a solution of fatty acid chloride in anhydrous pentane. The filter paper is then placed under a suction hood at ambient temperature, the pentane is removed by evaporation, and then placed in a ventilated oven at a temperature of 150° C. This impregnation enables optimal contact of the cellulose fibers of the paper with the fatty acid chloride and acylation of all the reactive hydroxyl groups present on the filter paper. The acylated filter paper has excellent hydrophobicity, as can be seen from its water repellent properties. Nevertheless, this method is difficult to implement in practice. The spontaneous evaporation of pentane and the resulting cooling lead to condensation of atmospheric moisture on the filter paper, increasing the natural moisture content of the paper. Therefore, the paper must be dried by equilibration at 105° C. for 24 hours and the reaction must be carried out under low moisture conditions (e.g. in a conditioned air atmosphere). Under these conditions, a significant hydrophobic property can be obtained using an amount of fatty acid chloride of about 0.1% relative to the weight of the paper. Under these conditions, a grafting rate of 50% can be obtained using stearic acid chloride. Nothing prevents overcoming the moisture problem by increasing the amount of stearic acid chloride and thus providing for the consumption of stearic acid chloride. However, this method is not satisfactory because it leads to the formation of free stearic acid, which has amphiphilic properties. This method also requires the removal of excess stearic acid chloride at the end of the reaction. In fact, excess residual stearic acid chloride is problematic. It is able to hydrolyze and produce free fatty acids and hydrochloric acid (HCl). The presence of HCl weakens the paper by hydrolysis of the glycosidic bonds of the cellulose. Due to their surfactant properties, free fatty acids themselves tend to reduce the hydrophobicity of the paper. Solutions are therefore sought to maintain the best quality of grafting and the best hydrophobic properties by limiting the formation of moisture and limiting - or even by completely eliminating - the amount of residual free fatty acid chloride and acid.

[0009] Furthermore, the process described in WO99 / 08784 inevitably involves the use of solutions of fatty acid chlorides in non-polar solvent media of the pentane, hexane or petroleum ether type, which may be toxic to humans and / or the environment. Pentane is highly volatile, which obviously entails the problem of its high flammability, which makes it impractical to use, especially on an industrial scale.

[0010] A solution to at least some of these disadvantages is to replace the highly volatile pentane with a non-polar solvent such as petroleum ether 100 / 150 with a lower volatility. However, on the other hand, although the evaporation of petroleum ether 100 / 150 is not accompanied by a significant condensation of moisture, the fraction of petroleum ether 100 / 150 inevitably remains in contact with the cellulose fibers of the paper material. The inventor has particularly observed that the removal of petroleum ether 100 / 150 by evaporation at 150°C is slow and incomplete. The inventor has observed the residual presence of petroleum ether 100 / 150 by opening an oven containing filter paper impregnated with petroleum ether 100 / 150 and heated at 150°C. The inventor believes that this condensation mist is caused by a mixture of hot air from the oven and external cold air and its cooling. The excess of fatty acid chlorides may also be revealed by the formation of this condensation mist. In addition, the inventor has observed that the presence of petroleum ether 100 / 150 residues has an adverse effect on the color development reaction itself. In particular, in order to obtain a contact angle value of about 150°, it is necessary to use at least five times the amount of fatty acid chloride required for a 0.1% by weight solution of fatty acid chloride in pentane to achieve this result. The inventors believe that the presence of these residual fractions of petroleum ether 100 / 150 slows down the reaction by keeping the fatty acid chloride in an at least partially solvated state and not allowing a reduction in the activation energy of the reaction. Higher concentrations of the reactants would be necessary. The presence of such residual fractions of petroleum ether 100 / 150 can also lead to deep fiber acylation of the paper material.

[0011] FR2925910 describes this method of acylation by impregnation with a solution of fatty acid chloride in petroleum ether 100 / 150 for treating paper coated with a layer of polyvinyl alcohol (PVA). This acylation method using fatty acid chloride in petroleum ether solution makes it possible to render the PVA layer hydrophobic, but the inventors have found that better hydrophobicity results can be obtained by impregnation with a lower concentration of fatty acid chloride in pentane. Moreover, these methods of treatment by impregnation are not suitable for the treatment of non-porous coated paper, since it is desirable to deposit the fatty acid chloride only on the coated side and not to impregnate the entire paper unnecessarily.

[0012] The present invention therefore aims to overcome these disadvantages.

[0013] In particular, the object of the present invention is to provide a process for the acylation of solid materials bearing reactive hydroxyl groups, which process makes it possible to obtain acylated materials having a high hydrophobicity and being substantially free of residual fatty acid chlorides and residual fatty acids. The present invention therefore aims to provide such a simplified process, since it does not require the elimination of residual excess fatty acid chlorides.

[0014] The present invention also aims to provide such a process which is more energy efficient than known acylation processes, since it does not require the establishment of a hot air stream to eliminate this excess fatty acid chloride.

[0015] Furthermore, it is an object of the present invention to provide such a process which is economical since the amount of fatty acid chloride applied to the paper material can be reduced relative to paper materials obtained by known acylation processes, the hydrophobicity of which is at least equal or even increased.

[0016] A method for the acylation of hydroxylated substrates that can be used on an industrial scale is described in FR2967363. FR2967363 describes the continuous acylation of a cellulose material strip (e.g., paper or paperboard) that moves between a reel and a device for rewinding the acylated cellulose material strip. The problem solved by FR2967363 is to enable fatty acyl chlorides to be deposited on the surface of a moving cellulose material. The solution of FR2967363 is to deposit fatty acyl chlorides in contact with a moving cellulose material by a printing technique, and then to heat the deposit by contact with a heated roller. In the method of FR2967363, fatty acyl chlorides are deposited on the surface of a moving cellulose material in the form of a plurality of clusters that correspond to the grid units of an anilox roller of a flexographic or photoengraving printing device.

[0017] Flexographic and photoengraving deposition devices are suitable for printing technology, and the inventors have observed that, even if they partially work, they are not optimized for the purpose of color development reaction. Due to the minimum size of the grid unit of the anilox roller, it is impossible to fully limit the amount of fatty acid chloride deposited on the cellulosic material to the amount of fatty acid chloride required for color development generation (chromatogeny). Therefore, the method using FR2967363 leads to the formation of condensation mist above the cellulosic material at high temperature on the heating roller, which characterizes the excessive acyl chloride deposited on the cellulosic material. In addition, the inventors have observed that the use of the FR2967363 method systematically leads to the hydrophobicity value of the acylated cellulose material being lower than the hydrophobicity value obtained by impregnation with a solution of fatty acid chloride in pentane under controlled atmospheric humidity conditions. Not only is the amount of deposited fatty acid chloride too much, but the amount is not uniformly deposited on the entire specific surface area of ​​the cellulosic material. Instead, it is deposited in the form of discrete clusters, each cluster corresponding to a printed pixel. Different from the method by pentane solution impregnation, this method causes the basic uniform deposition of fatty acid chloride monolayer on the filter paper surface, and these clusters are formed by a large amount of molecules, have low specific surface area, and this is unfavorable for liquid / vapor equilibrium to be transformed to gaseous form.For this transformation, such cluster needs to apply higher temperature, and this is actually harmful to the characteristic condensation / evaporation of color development generation.Therefore, the hydrophobicity value obtained is not optimal.The hydrophobicity of gained acylated cellulose material can not make it have the optimal impermeability for water that is long-lasting enough in time.In this respect, the contact angle value of a drop of pure water deposited on the acylated cellulose material according to FR2967363 method is certainly greater than 90 °, but this value does not reach the optimum value of 150 °.It is also observed that this acylated cellulose material comprises a large amount of free fatty acids that promote its hydrophobicity and water impermeability characteristics of degradation.

[0018] The inventors also believe that the deposition of fatty acid chlorides deposited in the form of such clusters (FR2967363) leads to the formation of a fat layer that is not bound to the cellulosic material, trapping the water contained in the volume of the cellulosic material and preventing its removal. This would lead to undesirable hydrolysis of the fatty acid chlorides. The fact that an excess of fatty acid chlorides is used would also lead to the accumulation of volatile impurities associated with the fatty acid chlorides, such as free fatty acids, which are not easily volatile and have the risk of accumulating on the cellulosic material.

[0019] With regard to the treatment of airtight cellulose materials where it is desired to treat only one of the two main faces, the method of FR2967363 appears to be more suitable than the pentane impregnation method, where the fatty acid chloride can only be deposited on one of the two faces of the cellulose material. However, the amount of fatty acid chloride deposited by the printing method is excessive and distributed in a discontinuous manner. The resulting hydrophobic properties are lower than those obtained with the pentane impregnation method.

[0020] Therefore, there is no high performance method for depositing fatty acid chlorides on cellulosic materials which results in acylated materials having satisfactory hydrophobicity.

[0021] The present invention therefore aims to overcome these disadvantages.

[0022] The present invention aims in particular to provide a manual process for the acylation of solid materials bearing reactive hydroxyl groups which is an improvement over the process of WO 99 / 08784 by impregnation with a solution of a fatty acid chloride in pentane.

[0023] The present invention also aims to provide such a manual process for solvent-free acylation which makes it possible to treat a piece of solid material carrying reactive hydroxyl groups, in particular cellulosic material, especially paper material, individually with a grafting efficiency at least equal to or even improved relative to the grafting efficiency of the process of WO99 / 08784.

[0024] The present invention also aims to provide such a manual process for acylation which does not require the use of environmentally toxic organic solvents.

[0025] The present invention also aims to provide such a manual process for acylation which does not require the use of non-polar organic solvents, regardless of their volatility.

[0026] The present invention also aims to provide such a manual method for acylation which can be carried out by any individual using commonly available equipment.

[0027] The invention also aims to provide such a manual method for acylation of cellulose material, in particular paper material, for the separate production of a filter protection device which is permeable to gases, in particular to the atmosphere, and impermeable to aqueous liquids.

[0028] In particular, the present invention aims to provide such a manual method for acylation of paper materials for the manufacture of masks for protection against pathogenic microorganisms (bacteria, fungi, viruses).

[0029] However, the present invention also aims at providing an industrial process for the acylation of a moving web or strip of solid material, especially cellulosic material, and especially paper material, carrying reactive hydroxyl groups.

[0030] The present invention aims in particular to provide such an industrial acylation process having an improved efficiency compared to the efficiency of the FR2967363 process.

[0031] The present invention also aims to provide such an industrial acylation process which is simplified compared to the process of FR2967363.

[0032] The present invention therefore aims to provide an industrial acylation process which is compatible with the technical limitations associated with the speed of operation of solid materials carrying reactive hydroxyl groups, in particular cellulose materials, and especially paper materials, and with the technical limitations associated with a high productivity of such acylated solid materials.

[0033] The invention also aims at providing such an industrial process for acylation of a web of cellulose material, in particular paper material, for producing a filter-protective device which is permeable to gases, in particular to atmospheric air, and impermeable to aqueous liquids.

[0034] In particular, the present invention aims to provide such an industrial acylation process for the manufacture of masks for protection against pathogenic microorganisms (bacteria, fungi, viruses).

[0035] The present invention therefore relates to a process for the acylation of solid materials carrying hydroxyl (—OH) groups, called reactive hydroxyl groups, which are accessible and capable of reacting with gaseous fatty acid chlorides, wherein:

[0036] - distributing at least one fatty acid chloride at least on the surface of the solid material using a distributor device and, if necessary, at a depth over at least one thickness portion of the solid phase material, the distributor device having an application surface suitable for depositing the at least one fatty acid chloride from the application surface at least on the surface of the solid material;

[0037] - heating said at least one fatty acid chloride distributed at least on the surface of said solid material at a temperature (called acylation temperature) below the vaporization temperature of at least one, in particular each, fatty acid chloride, so as to render said solid material acylated by reaction of at least one gaseous fatty acid chloride with at least one said reactive hydroxyl group of said solid material;

[0038] - directing a stream of a gaseous composition, in particular a stream of an inert gaseous composition, in particular an atmospheric gas, in particular a gas inert with respect to the acylation reaction, onto said solid material at said acylation temperature in order to entrain at a distance from said solid material at least a portion of the gaseous hydrochloric acid formed by the acylation reaction;

[0039] Characterized in that the application surface of the dispenser device is velvet provided with velvet thread-like elements, which is non-reactive with respect to the at least one fatty acid chloride and is suitable for:

[0040] o absorbing the at least one fatty acid chloride by contacting with the at least one fatty acid chloride, and;

[0041] o releasing the at least one fatty acid chloride by contacting the filamentary elements of the velvet with the solid material;

[0042] The step of distributing is performed so that the at least one fatty acid chloride is distributed at 20 mg / m 2 and 1g / m 2 An amount between the surface areas of the solid material is distributed over the solid material.

[0043] This solid material with hydroxyl groups (-OH) (called reactive hydroxyl groups, which are accessible and capable of reacting with gaseous fatty acid chlorides) can be a cellulosic material. It can be a paper or paperboard material. In some embodiments, the solid material can be a fabric. Advantageously, the solid material has an irregular and very rough surface appearance. This solid material can be porous or non-porous. However, there is nothing to prevent the solid material from being a calendered paper material with a regular surface appearance of low roughness. It can also be a non-porous solid material with reactive hydroxyl groups, which are carried by at least one polymer with such reactive hydroxyl groups. This polymer can be PVA (polyvinyl alcohol). In some embodiments, the solid material has an outer surface layer formed by polyvinyl alcohol. In particular, it can be a cellulosic material, especially a paper material, which becomes airtight and non-porous by applying a PVA layer to the surface, as described in FR2925910.

[0044] The inventors have found that the process according to the invention makes it possible to deposit at least on the surface of the solid material, that is to say on the surface and, if necessary, over at least one thickness portion of the solid material, in particular when the solid material is porous and / or has an irregular surface, an amount of at least one fatty acyl chloride in an amount at least equal to, or even lower than, the minimum amount of fatty acyl chloride deposited during implementation of the process by impregnation with a solution of fatty acyl chloride in pentane ( WO 99 / 08784 ), and at the same time to produce hydrophobic properties, in particular quantified by measuring the Cobb index and / or by measuring the contact angle formed by a water droplet deposited on the surface of the acylated solid material and / or by carrying out a tightness test on a water bag, which are substantially equivalent or even improved.

[0045] The inventor has also found that the reaction conditions of the known methods for the deposition of substantially pure fatty acid chlorides by flexographic printing or photoengraving with petroleum ether 100 / 150 to solid material are not optimal, and the fatty acid chlorides used are excessive relative to the solid material, so that the solid material processed by these known methods contains a significant residual amount of free fatty acid chlorides. The inventor has found that the solid material processed by these known methods contains a residual amount of fatty acid chlorides, although a final purge (or flushing) step intended to eliminate any residual fatty acid chlorides has been used. The presence of residual fatty acid chlorides has brought the problem of eliminating these residual fatty acid chlorides. Specifically, this residual free fatty acid chloride can be decomposed by hydrolysis in the form of free fatty acids and hydrochloric acid that can degrade the solid material. In addition, these reactive residual fatty acid chlorides constitute toxicity problems for the application of food packaging and biomedical fields.

[0046] In addition, the fact that the hydrophobic properties of the paper material treated by the known method of impregnation with petroleum ether 100 / 150 and application by using an anilox roller are lower than the expected value will promote the increase in the amount of fatty acid chloride deposited on the solid material to improve the degree of grafting. However, the inventors have realized that the total amount of fatty acid chloride deposited on the solid material is not important, what is important is that the fatty acid chloride is distributed and spread as evenly as possible on the entire surface of the solid material, and if necessary at the depth of the solid material - especially when the solid material is porous and / or has an irregular surface - and there is no residual solvent. In fact, according to the present invention, the fact that a limited amount of fatty acid chloride is deposited on the solid material makes it possible to reduce or even eliminate the amount of residual fatty acid chloride, improve the economic yield of the reaction, and avoid the complicated implementation of the treatment for eliminating excessive acid chlorides while improving the hydrophobic properties. The fact that excessive fatty acid chlorides are reduced or even eliminated makes it possible to reduce or even eliminate free fatty acids that can be produced by hydrolysis and cannot be eliminated by hot air purging. Therefore, the method of the present invention is simpler, more effective and more economical than known methods.

[0047] The inventors have observed, quite surprisingly and unexpectedly, that small amounts of fatty acid chloride can be distributed in a regular, reproducible and uniform manner on the surface of said solid material using a dispenser device having an application surface formed by a velvet provided with filamentary elements of the velvet. Even more surprisingly, these small amounts of fatty acid chloride are sufficient to impart to the solid material a hydrophobicity, impermeability to aqueous solutions and water repellency which is at least equal to or even generally greater than that of the acylated solid materials obtained by known methods, in particular by impregnation with solutions of fatty acid chlorides in pentane (WO 99 / 08784).

[0048] By comparison, the inventors have observed that it is not possible to obtain such properties with the same amount of fatty acid chloride using a dispenser device having an application surface formed by a foam without filamentary elements (which therefore does not constitute the present invention). Such a foam is certainly deformable macroscopically, but has a high cohesion and low deformability microscopically and cannot come into close contact with all the surface microscopic irregularities of the solid material, as the filamentary elements of velvet do. The foam loaded with fatty acid chloride adheres to the solid material without the smooth effect of velvet, and it is tricky or even impossible to use it on an industrial scale.

[0049] In certain embodiments of the method according to the invention, the solid material is a porous solid material and at least one fatty acid chloride is distributed at least on the surface of the porous solid material and at a depth of at least one thickness portion of the porous solid material using a distributor device. The distribution step is performed so as to form a deposit of the at least one fatty acid chloride on the solid material which is as spread as possible - and as thin as possible considering the amount of deposition - in contact with the reactive hydroxyl groups of the solid material. This spread and this thin thickness of the deposit are favorable to the gaseous state of the fatty acid chloride. The chromogenic acylation reaction then proceeds efficiently.

[0050] In certain embodiments according to the invention, the dispenser device has an application surface formed by velvet provided with velvet filamentary elements which are oleophilic (have an affinity for fatty substances). However, in other embodiments according to the invention, nothing prevents the dispenser device from having an application surface formed by velvet provided with oleophobic velvet filamentary elements. In particular, they may be coated with a perfluorinated coating, in particular Surprisingly, the inventors have observed that such oleophobic velvet filamentary elements, despite their oleophobic properties, absorb fatty acid chlorides which are lipophilic and oleophilic. The amount of fatty acid chloride absorbed is of course low, but sufficient to deposit and distribute the fatty acid chloride on the solid material and to hydrophobize it.

[0051] According to the invention, the application surface of the application roller is formed of a chemically stable, wear-resistant and heat-resistant material. Any type of suitable lipophilic material can be used. Advantageously, the application roller is of the "paint roller" type.

[0052] In certain embodiments of the method according to the invention, the distribution step is carried out at a temperature between 40° C. and 190° C. In certain embodiments of the method according to the invention, nothing prevents the deposition and distribution of the at least one fatty acid chloride from being carried out on a solid material preheated to reach the acylation temperature. It is observed that the acylation reaction occurs almost instantaneously during the distribution of the at least one fatty acid chloride. In certain embodiments of the acylation method according to the invention - in particular in certain embodiments in which the solid material has a high water content - nothing prevents the solid material from being heated before the deposition of the at least one fatty acid chloride or before the distribution step.

[0053] Advantageously, the velvet filamentary elements are flexible and suitable for absorbing said at least one fatty acid chloride and for releasing at least a portion of said at least one fatty acid chloride loaded on the velvet filamentary elements on the surface and optionally at least one thickness portion of said solid material, by elastic deformation of the loaded flexible velvet filamentary elements.

[0054] In certain embodiments, the velvet thread-like elements are formed from at least one material selected from the group consisting of keratin fibers, in particular wool fibers, especially mohair fibers, aramid fibers, polyester fibers, polyamide fibers, acrylic fibers, fluorinated, in particular perfluorinated fibers, fibers provided with a fluorinated, in particular perfluorinated coating, microfibers, in particular microfibers having a linear density of less than 1 g / 10 km (1 tex), woven microfibers, ultramicrofibers having a count of less than 0.4 tex and supermicrofibers having a count of less than 0.1 tex. Advantageously, the velvet thread-like elements are chosen because of their chemical inertness and their high heat and wear resistance. In certain embodiments, the velvet thread-like elements have a length between 1 mm and 10 mm, in particular between 2 mm and 6 mm, preferably about 4 mm. In certain embodiments, the velvet thread-like elements have a cross-section with a diameter between 1 μm and 100 μm. In certain embodiments of the acylation process according to the invention, the implantation density of the velvet thread-like elements on the surface of the application roller is 100 μm per mm 2 Application roller surface area 10 filamentary elements and per mm 2 The surface area of ​​the application roller is between 500 filamentary elements. The velvet filamentary elements are selected to have a stiffness imparted by the rotation of the application roller, in particular during the rotation of the application roller, sufficient to enable the at least one fatty acid chloride to be applied at a depth of at least one thickness portion of the solid material, in particular the porous solid material, without damaging the solid material. Advantageously, according to all embodiments of the method according to the invention, the velvet filamentary elements have a flexibility selected to be in contact with the solid material without damaging the solid material.

[0055] In certain embodiments of the method according to the invention, the at least one fatty acid chloride is distributed at least on the surface of the solid material by brushing the free longitudinal ends of the velvet thread-like elements of the application surface onto the surface of the solid material. In particular, the at least one fatty acid chloride is distributed at least on the surface of the solid material by the relative displacement of the application surface of the distributor device and the solid material, so that the free ends of the velvet thread-like elements are in contact with the solid material at least on the surface of the solid material, and preferably in contact with at least one thickness portion of the solid material, in particular when the latter is porous, so that the velvet thread-like elements release the fatty acid chloride when in contact with the solid material. Advantageously, the at least one fatty acid chloride is distributed at least on the surface of the solid material by brushing, while applying sufficient pressure to the solid material to enable the fatty acid chloride to be transferred between the thread-like elements of the velvet and the solid material, but without deteriorating the solid material.

[0056] In certain embodiments of the method according to the invention, the dispenser device comprises at least one application roller having said application surface. Said at least one application roller is rotatably mounted relative to said solid material, and said at least one fatty acid chloride is dispensed by rotating said at least one application roller, said application surface being in contact with said solid material. In certain specific embodiments according to the invention, there is nothing to prevent said at least one fatty acid chloride from being distributed on the surface of said solid material by means of rotating the application roller by rolling the application surface of the application roller on the surface of said solid material.

[0057] In a first industrial scale embodiment of the process according to the invention, said solid material is in the form of a strip moving in a running direction parallel to the largest dimension of the strip, between a reel upstream of said strip of acylated solid material and a take-up roll downstream of the strip;

[0058] - continuous deposition of said at least one fatty acid chloride, in particular at a fixed station, on at least one free surface of said mobile solid material, and;

[0059] - the at least one fatty acid chloride deposited on the surface of the solid material is distributed at least on the surface of the solid material by means of a distributor device;

[0060] - heating the solid material so that the at least one fatty acid chloride distributed at least on the surface of the solid material reaches the acylation temperature on the solid material;

[0061] - directing a stream of gaseous composition at said acylation temperature onto said solid material, thereby acylating said solid material.

[0062] The inventors have established that the method according to the invention can be used on an industrial scale for strips of said solid material, which strips move in particular at high operating speeds of more than 50 m / min. According to certain embodiments, the application roller rotates about an axis of rotation:

[0063] - extends in a plane parallel to the main plane of the strip, and;

[0064] - substantially perpendicular to the direction of travel of said solid material.

[0065] According to other embodiments, nothing prevents the application roller from rotating about the axis of rotation:

[0066] - extends in a plane parallel to the main plane of the strip, and;

[0067] - not perpendicular and not parallel to the running direction of the solid material.

[0068] In a first industrial-scale embodiment of the method according to the invention, the at least one acid chloride is continuously deposited by means of a printing device, in particular at a fixed station, on at least one free main surface of the solid material. In a first industrial-scale embodiment of the method according to the invention, the printing device is selected from a flexographic printing device and a photolithographic printing device.

[0069] In certain particular embodiments of the invention, nothing prevents provision being made for the distribution of the at least one acid chloride onto the moving strip of solid material to be carried out with the aid of two application rollers rotating about mutually parallel axes of rotation, each of the opposite main faces of the solid material strip being in contact with one of the rollers, at least one rotatable application roller having an application surface provided with velvet filamentary elements.

[0070] In a second industrial scale embodiment of the method according to the invention, said solid material is in the form of a strip moving in a running direction parallel to the largest dimension of the strip, between a reel upstream of said strip of acylated solid material and a take-up roller downstream of the strip;

[0071] - the at least one fatty acid chloride is continuously deposited on an application roller rotating in contact with the solid material, whereby the at least one fatty acid chloride is distributed from the rotating application roller at least on the surface of the solid material, and;

[0072] - heating the solid material so that the at least one fatty acid chloride distributed at least on the surface of the solid material reaches the acylation temperature, and;

[0073] - directing a stream of gaseous composition onto said solid material at said acylation temperature.

[0074] In a second industrial-scale embodiment of the method according to the invention, the at least one fatty acid chloride is deposited on a rotating applicator roller by bringing the rotating applicator roller into contact with an anilox roller of a printing device loaded with the at least one fatty acid chloride. Any type of anilox roller can be used. It can be selected from the group formed by a flexographic printing device and a photoengraving printing device. Any type of anilox roller can be used by adapting the size of its cells and its surface density to the amount of fatty acid chloride to be deposited. There is nothing to prevent the rotation speed of the anilox roller from being different from the rotation speed of the applicator roller.

[0075] In certain industrial-scale embodiments of the method according to the invention, the rotatable application roller is rotated at a selected rotational angular velocity so that the free end of the velvet filamentary element is rotated at a linear velocity having a value different from the value of the running velocity of the solid material. In these embodiments, the linear running velocity of the free end of the velvet filamentary element and the running velocity of the solid material are not synchronized, thereby producing a brushing on the solid material, resulting in the spreading of the at least one fatty acid chloride at least on the surface of the solid material.

[0076] In certain industrial-scale embodiments of the acylation process according to the invention, the rotatable application roller is rotated in a selected rotational direction such that the free end of the velvet filamentary element moves counter-directionally to the movement of the strip of solid material. However, in other industrial-scale embodiments of the acylation process according to the invention, nothing prevents the rotatable application roller from being rotated in a selected rotational direction such that the free end of the velvet filamentary element moves co-directionally (in the same direction and in the same sense) to the movement of the solid material.

[0077] The inventors have also determined that the method according to the invention can be implemented on a manual scale. In a manual embodiment of the acylation method according to the invention, the at least one acyl chloride is deposited on the surface of the solid material by means of a dispenser device having an application surface previously loaded with the at least one fatty acyl chloride. In a manual embodiment of the acylation method according to the invention, the dispenser device comprises an application roller or "painting roller", a certain amount of the at least one fatty acyl chloride is deposited in a flat-bottomed container, and the at least one fatty acyl chloride is loaded on the velvet filamentary element of the application roller by rolling the application roller in contact with the at least one fatty acyl chloride. In these embodiments, the application roller alternates with a rotational movement and a back and forth movement manually applied to the dispenser device. In these embodiments of the method according to the invention, the at least one fatty acyl chloride is loaded on the velvet filamentary element by rolling and pressing the application roller in contact with the flat bottom of the container.

[0078] In some of these embodiments of the acylation process according to the invention, the solid material is a flexible material, that is to say it is deformable under the effect of its own weight. In some of these embodiments, the solid material may be a paper material (that is to say essentially a cellulose material), in the form of paper known as "kitchen roll", toilet paper, paper towel, filter paper. There is also nothing to prevent the solid material from being selected from the group formed by crosslinked paper materials, in which the rotational flowability of the cellulose fibers thus crosslinked is limited and their mechanical strength properties are generally improved and the wet strength properties are especially improved.

[0079] In certain embodiments of the acylation method according to the invention, the solid material is a paper material (that is to say essentially a cellulose material) formed by all or part of a disposable tissue. In some of these embodiments, the solid material is a disposable tissue. In some of these embodiments of the method according to the invention, the solid material is formed by a plurality of cellulose layers, the cellulose layers having a grammage of less than 30 g / m 2 , especially less than 20g / m 2 , preferably at 10g / m 2 and 30g / m 2 More preferably, between 10 g / m 2 and 20g / m 2 Advantageously, in some of these embodiments, each cellulose layer is formed of cross-linked cellulose fibers, held together by hydrogen bonds and by covalent bonds formed with at least one group of cross-linking atoms. Advantageously, the cross-linking atomic group is a derivative of 1-chloro-2,3-epoxypropane (epichlorohydrin).

[0080] In certain other embodiments of the acylation process according to the invention, the solid material is rigid, that is, it cannot be substantially deformed under its own weight. In these other embodiments, the solid material may be a sheet of cardboard, in particular a corrugated cardboard. In these other embodiments, the solid material consists of a sheet having a grammage greater than 160 g / m 2 The cellulose layer is formed.

[0081] In certain embodiments of the acylation process according to the present invention, the acylation temperature is between 140° C. and 200° C. The value of the acylation temperature is selected with respect to the evaporation temperature of each fatty acid chloride at atmospheric pressure.

[0082] In certain embodiments of the acylation process according to the invention, at least one fatty acid chloride is selected from the group formed by: an acid chloride of formula R-CO-Cl, wherein R is a hydrocarbon chain having a number of carbon atoms between 17 (inclusive) and 29 (inclusive), in particular between 21 (inclusive) and 29 (inclusive). Advantageously, at least one fatty acid chloride is behenoyl chloride (C 22 H 43 Advantageously, at least one fatty acid chloride is palmitoyl chloride (C 16 H 31 Advantageously, at least one fatty acid chloride is stearoyl chloride (C 18 H 35 OCl).

[0083] In certain embodiments of the acylation process according to the invention, a composition formed solely from the at least one fatty acid chloride, referred to as the acylation composition, is distributed at least on the surface of the solid material - and if desired, at and above at least one thickness portion of the depth of the solid material. In these embodiments, the acylation composition does not contain (except for possible trace amounts) any solvent medium, in particular any non-polar solvent medium different from the fatty acid chloride or chlorides.

[0084] That is, in other embodiments, nothing can prevent the acylation composition from comprising the at least one fatty acyl chloride and acetyl chloride. The inventors have found that acetyl chloride (which is not a fatty acyl chloride within the meaning of the present invention) can react spontaneously with the free water molecules present in the solid material, and makes it possible to protect the fatty acyl chloride from hydrolysis. The inventors have also been surprised to observe that acetyl chloride does not react with the hydroxyl groups of the cellulose fibers of the paper material under the conditions of acylation of the paper material, and does not acetylate the cellulose under the conditions of the color development reaction, nor does it react with the reactive hydroxyl groups of other hydroxylated polymers such as polyvinyl alcohol. Advantageously, acetic acid as a hydrolyzate of acetyl chloride has sufficient volatility, and is suitable for elimination from the solid material by entrainment via a gaseous composition stream. Advantageously, acetyl chloride is used as a protective agent for one or more fatty acyl chlorides. Advantageously, acetyl chloride is used as a transchlorination reagent, which makes it possible to recover the fatty acyl chloride from the possible free fatty acids hydrolyzed during the reaction.

[0085] The invention also relates to an acylated solid material obtainable by the process according to the invention.

[0086] The invention also relates to a method for acylation of a solid material with hydroxyl groups (-OH), called reactive hydroxyl groups, which are accessible and capable of reacting with gaseous fatty acid chlorides, characterized by combining all or part of the features mentioned above or below. Regardless of the formal representation given, unless otherwise explicitly indicated, the various features mentioned above or below should not be considered to be closely or inseparably linked to each other, and the invention can only relate to one of these structural or functional features, or only a part of these structural or functional features, or only a part of one of these structural or functional features, or any other group combining or juxtaposing all or part of the structural or functional features.

[0087] Other objects, characteristics and advantages of the invention will become apparent on reading the following description, which refers to the accompanying drawings and to examples given which are not limiting of the invention in any way, and in which:

[0088] - Figure 1 is a schematic diagram showing a first embodiment of the method according to the present invention;

[0089] - Figure 2 It is a schematic diagram illustrating a second embodiment of the method according to the invention which can be implemented on an industrial scale.

[0090] In the method according to the invention for acylation of a solid material carrying hydroxyl groups (–OH), called reactive hydroxyl groups, which are accessible and capable of reacting with gaseous fatty acid chlorides, in particular for acylation of a cellulose material, in particular a paper material, at least one fatty acid chloride is distributed on the surface and on at least one thickness portion of said solid material by means of a dispenser device having an application surface suitable for depositing said at least one fatty acid chloride from said application surface at least on the surface of said solid material. The application surface of the dispenser device is a velvet provided with velvet thread-like elements, which are non-reactive with respect to said at least one fatty acid chloride. The application device comprises at least one application roller having said application surface, said at least one application roller being rotatably mounted relative to the flat material. The application roller may be an application roller of the “velvet” type or a “coating” roller. As a non-limiting example, it may be:

[0091] - "Nespoli" velvet roller (Nespoli Group, La Capelle, France), the application surface of which is made of velvet provided with a coating comprising The velvet roller comprises a textile fiber and at least partially oleophobic filamentary elements. For example, such a velvet roller has a length of about 10 cm and a diameter of 30 mm. The length of the fiber is between 4 mm and 12 mm, and preferably about 5 mm;

[0092] - a "DIALL" paint roller (Kingfisher International Products Ltd., London, UK), the application surface of which is a rotating cylinder having a length of 110 mm and a cross-sectional diameter of 40 mm and the application face of which comprises mohair fibers;

[0093] - "Roulor Professionnel" paint roller (Nespoli Group, La Capelle, France), the application surface of which is made of velvet provided with a coating comprising polyester fibers, and at least partially oleophobic filamentary elements;

[0094] - Pure wool velvet roller (OCAI, Dormont, France), the fibers of which have a length of 4 mm.

[0095] The inventors have observed that, in the chromogenic acylation process according to the invention, with the aid of such an application roller of the "paint" or "velvet" type, using a step of distributing one or more acid chlorides on said solid material, it is possible to obtain an acylated solid material having hydrophobic properties at least comparable to those of a paper material treated by a process for impregnating the paper material with a solution of fatty acid chlorides in pentane (WO 99 / 08784), at the same amount of reactants deposited, but with the considerable advantage of not using solvents, in particular organic solvents. The hydrophobic properties obtained with the process according to the invention are even superior to those obtained by impregnation with a solution of fatty acid chlorides in petroleum ether 100 / 150 or by a process for depositing the fatty acid chlorides with the aid of an anilox roll, at the same amount of fatty acid chloride deposited. These two prior art processes produce acylated solid materials whose hydrophobic properties are disappointing, inevitably use an excess of fatty acid chloride and require a complex step of eliminating the excess fatty acid chloride by blowing with hot air.

[0096] The quality of the acylation is defined by evaluating the hydrophobicity of the acylated solid material by measuring the contact angle formed between the main plane of the acylated solid material and a drop of pure water deposited on the surface of the acylated solid. Typically, the contact angle value of the acylated solid material is between 90° and 150°, a contact angle value of 150° corresponding to a particularly hydrophobic and water-repellent material. The quality of the acylation is also determined by measuring the time period during which the contact angle value between 90° and 150° is maintained at ambient temperature and by the water bag test. The water bag test can only be implemented with a solid material in the form of a substantially square flexible sheet, so that its corners are brought together to form a water bag. The impermeability of the water bag is analyzed by monitoring the loss of water (taking into account evaporation).

[0097] Hydrophobicity can also be evaluated by observing water repellency. 1 mL of distilled water is deposited on the surface of a solid material, and it is observed whether the formed water droplets roll on the surface by adhering or not adhering to the surface of the solid material. Satisfactory water repellency corresponds to a contact angle of about 150°.

[0098] The inventors have been able to observe that the value of the contact angle formed between the main planes of the solid material acylated by the method of impregnation with a solution of the fatty acid chloride in pentane and by the method according to the invention is close to 150°, while the value of the contact angle measured on the solid material acylated by the method of impregnation with a solution of the fatty acid chloride in petroleum ether 100 / 150 and by deposition with the aid of an anilox roll is at most equal to 130°.

[0099] Characterization of the presence of residual fatty acyl chlorides during acylation - exposure tests

[0100] In fact, the amount of fatty acyl chloride deposited on a first sheet of solid material, called the sheet to be acylated, reacts only partially or completely with said solid material of said sheet to be acylated, characterized in that a certain amount of fatty acyl chloride is deposited on said sheet to be acylated and in contact with the main face of said sheet to be acylated, opposite to the face receiving the hot air flow, aimed at promoting the change of the fatty acyl chloride from the liquid to the gaseous state and entraining the hydrochloric acid formed by the acylation reaction, with any paper, called the exposed sheet. When the fatty acyl chloride is present in excess, it is entrained by the air flow and brought into contact with said exposed sheet, wherein it reacts with said reactive hydroxyl groups of the cellulose fibers. Said exposed sheet is analyzed with respect to its hydrophobic properties. If the given amount of fatty acyl chloride brought into contact with said sheet to be acylated is such that the fatty acyl chloride does not react with said sheet to be acylated and is brought into contact with said exposed sheet by the air flow, the hydrophobic properties of said exposed sheet are increased. In contrast, if a given amount of fatty acid chloride contacted with the sheet to be acylated is such that most or all of the fatty acid chloride deposited on the sheet to be acylated reacts with the sheet to be acylated, the exposed sheet remains little or not hydrophobic.

[0101] It is observed that, under conditions strictly comparable to those described in Example 1 below, the acylation process according to the invention and also the process of acylation by impregnation with a 0.1% solution of acyl chloride in pentane do not lead to an increase in the hydrophobicity of the exposed sheet. This result shows that the fatty acid chloride reacts in the vast majority of cases with the sheet to be acylated. In contrast, the process by impregnation in petroleum ether 100 / 150 and the process of deposition by flexographic / photographic printing require an excess of acyl chloride and lead to the formation of highly hydrophobic exposed sheets. The process according to the invention makes it possible to maintain the excellent results obtained by pentane impregnation by depositing very small amounts of fatty acid chloride, but with the significant advantage of not using organic solvents.

[0102] Figure 1A first embodiment of the method according to the invention for acylation of paper material is schematically presented in . This first embodiment is a manual embodiment of the method according to the invention. This first embodiment can be carried out by a person without requiring specific equipment, appliances or protection which he / she cannot usually obtain commercially. Figure 1 In an embodiment of the method according to the invention for acylation of a solid material presented schematically, at least one fatty acid chloride 1 is selected from the group formed by: fatty acid chlorides of the formula R-CO-Cl, wherein R is a hydrocarbon chain having a number of carbon atoms between 17 (inclusive) and 29 (inclusive). In this method according to the invention, a dispenser device 2 is also selected, which has an application surface suitable for depositing the at least one fatty acid chloride 1 from the application surface at least on the surface of the solid material. Figure 1 In the embodiment presented, the dispenser device 2 is a "DIALL" paint roller 2 (Kingfisher International Products Ltd., London, UK), the application surface of which comprises mohair fibers. However, nothing prevents the dispenser roller from being a velvet having oleophobic properties, especially coated with A certain amount of fatty acid chloride 1 is placed in a flat bottom container, the size of which is set to be able to receive a paint roller 2 so that it can roll on the bottom of the container and load it with fatty acid chloride 1.

[0103] During the first step 11 of loading the coating roller 2, the coating roller 2 is in a new state and not loaded with fatty acid chloride, and an amount of about 1 mL of fatty acid chloride is placed in a flat-bottomed container. During the first step 11 of loading the coating roller 2, the coating roller 2 is manually driven so that the coating roller 2 moves in contact with the fatty acid chloride 1 so that the filamentary element of the coating roller 2 absorbs the fatty acid chloride 1 over the entire application surface of the coating roller 2. In order to limit the amount of fatty acid chloride 1 loaded on the coating roller 2, an optional step of removing excess fatty acid chloride 1 from the coating roller 2 is implemented by continuously rolling the coating roller 2 on several sheets of paper to use up the excess fatty acid chloride. A coating roller 4 loaded with fatty acid chloride 1 is thus obtained. Such a step of removing excess fatty acid chloride 1 is particularly necessary during the use of a dispenser roller with oleophobic velvet.

[0104] That is, during the subsequent step 11 of loading the coating roller 2, which has been previously loaded and used to apply the fatty acid chloride on the solid material, an amount of about 50 μL of the fatty acid chloride is placed in the flat-bottom container.

[0105] A sheet of solid material 3 is selected, for example a disposable paper towel 3. The sheet of paper material 3 is placed on a suitable support so that a certain amount of fatty acid chloride 1 can be transferred from the loaded coating roller 4 to the disposable paper towel 3. The application 12 is carried out by rolling the thus loaded coating roller 4 on the surface of the disposable paper towel 3. Preferably, the rolling 12 is carried out without applying a pressure other than the pressure required to roll the coating roller 4 on the disposable paper towel 3 (that is, between 0.1 and 0.2 kg / cm 2 ) is carried out with a moderate pressure between 10 and 15°. In this way, only a small amount of fatty acid chloride 1 is transferred to the disposable paper towel 3. However, the inventors have observed that even if the amount of fatty acid chloride 1 transferred to the disposable paper towel 3 is small, in any case it is sufficient to subsequently acylate the disposable paper towel 3 and make its hydrophobic properties at least equivalent to those obtained by impregnation with a solution of fatty acid chloride in pentane (WO 99 / 08784), but without the use of organic solvents. Thus, a disposable paper towel sheet 5 loaded with fatty acid chloride 1 is formed. The inventors believe that, due to the filamentary elements of the coating roller 2, the fatty acid chloride 1 applied to the surface of the disposable paper towel 3 is distributed on the surface of the loaded disposable paper towel 5, but also at least in the depth of the loaded disposable paper towel 5 and in contact with the cellulose fibers of the loaded disposable paper towel 5. In particular, the inventors believe that the filamentary elements of the coating roller 2 are flexible and elastically deformable in a transverse manner, so that the fatty acid chloride 1 can be distributed by brushing on at least one thickness portion of the disposable paper towel 3. The inventors believe that, considering the absence of solvent, the fatty acid chloride 1 does not form clusters during the evaporation of the organic solvent and is substantially uniformly distributed on the cellulose fibers of the loaded disposable tissue 5 .

[0106] exist Figure 1 In a first embodiment of the method according to the invention presented in , the acylation reaction of the disposable tissue 3 is induced during the combined step 13 of heating the loaded disposable tissue 5 and applying an air flow 6 at the surface of the loaded disposable tissue 5. The application of the air flow 6 enables a shift in the liquid / vapor equilibrium of the fatty acid chloride 1 distributed on the loaded disposable tissue 5 and the formation of a gaseous fatty acid chloride 1 reactive with respect to the acylation reaction. In addition, the simultaneous heating of the loaded disposable tissue 5 makes it possible to reach a colorimetric acylation temperature, via which the gaseous fatty acid chloride 1 reacts with the free hydroxyl groups of the cellulose fibers of the loaded disposable tissue 5, establishing ester bonds between the cellulose fibers and the acyl groups of the fatty acid chloride 1, thereby forming an acylated tissue 10. As a result of the acylation reaction, hydrochloric acid (HCl) is released. The air flow 6 applied to the loaded disposable tissue 5 makes it possible to move the hydrochloric acid formed by the reaction away from the loaded disposable tissue 5, so that the equilibrium of the acylation reaction is shifted in the direction of the formation of the acylated disposable tissue 10.

[0107] exist Figure 1 In the embodiment of the method according to the invention presented in , the step 13 of heating and applying the air flow 6 is carried out in a ventilated oven maintained at the acylation temperature. Due to the ventilation, the acylated disposable tissue 10 is free of hydrochloric acid. Due to the control of the amount of fatty acid chloride 1 loaded onto the disposable tissue 3 and the distribution of the fatty acid chloride 1 on the disposable tissue 3, the acylated disposable tissue 10 is free of free fatty acid chloride and free fatty acids. A subsequent step of eliminating excess fatty acid chloride 1 is not required.

[0108] Figure 2 A second embodiment of the process according to the invention for the acylation of paper material is schematically presented in . This second embodiment is an industrial scale embodiment of the process according to the invention.

[0109] As described in FR2967363, a device is selected for moving a paper material strip 9 moving between an upstream reel and a downstream device for rewinding an acylated paper strip 10. In certain embodiments, the paper material strip 9 moves at a speed between 30 and 100 meters per minute. At least one fatty acid chloride 1 is selected from the group formed by: fatty acid chlorides of the formula R-CO-Cl, wherein R is a hydrocarbon chain having a carbon number between 17 (inclusive) and 29 (inclusive). The step 15 of continuously depositing the at least one fatty acid chloride 1 on the moving paper strip 9 is implemented by any suitable device known to those skilled in the art. These devices can be selected from the group formed by a flexographic printing device and a photoengraving printing device, with an upstream printing device. Through this deposition step 15, a paper material 8 coated with a fatty acid chloride 1 is formed. At a downstream position relative to the printing device, the paper material 8 coated with the fatty acid chloride 1 is subjected to a step 14, which redistributes and spreads the fatty acid chloride on the surface on at least one depth portion of the coated paper material 8. This redistribution / spreading step is carried out by brushing the surface of the moving coated paper web 8 with a dispenser device 2 comprising an application surface formed by velvet provided with velvet thread-like elements that are non-reactive with respect to said at least one acid chloride. Advantageously, the dispenser device comprises a coating roller 2 that rotates counter to or in the direction of travel of the coated paper material web 8. The velvet thread-like elements, whether they are oleophilic or oleophobic, are suitable for:

[0110] o absorbing the at least one fatty acid chloride by contacting with the at least one fatty acid chloride, and;

[0111] o releasing the at least one fatty acid chloride by contacting the filamentary elements of the velvet with the coated material strip 8;

[0112] As a result of this redistribution / spreading step 14, a solid material strip 5 is formed which is loaded with a certain amount of said at least one fatty acid chloride. The inventors have observed in particular that even in the case of a small amount of fatty acid chloride 1 transferred to said solid material strip 5, and an amount of about 20 mg / m 2 , in any case it is sufficient to subsequently acylate the solid material and render its hydrophobic properties at least equivalent to those obtained by impregnation with a solution of fatty acid chloride in pentane (WO 99 / 08784), but without the use of an organic solvent.

[0113] exist Figure 2 In a second embodiment of the method according to the invention presented in , the acylation reaction of the solid material of the mobile strip is induced during a combined upstream step 13 of heating the loaded strip 5 and applying an air stream 6 at the surface of the loaded strip 5. The application of the air stream 6 enables the liquid / vapor equilibrium of the fatty acid chloride 1 distributed on the loaded strip 5 to be shifted and gaseous fatty acid chloride 1 reactive with respect to the acylation reaction to be formed. Furthermore, the simultaneous heating of the loaded strip 5 enables the colorimetric acylation temperature to be reached, via which the gaseous fatty acid chloride 1 reacts with the free hydroxyl groups of the solid material, establishing ester bonds between the solid material components and the acyl groups of the fatty acid chloride 1, thereby forming an acylated solid material strip 10. As a result of the acylation reaction, hydrochloric acid (HCl) is released. The air stream 6 applied to the loaded strip 5 enables the hydrochloric acid formed by the reaction to be moved away from the strip 5 in the form of a composition 7 of air loaded with hydrochloric acid, so that the equilibrium of the acylation reaction is shifted in the direction of the formation of the acylated paper material 10.

[0114] Example 1 - Acylation of solid materials according to the invention - Determination of the optimal conditions for the deposition of stearoyl chloride

[0115] About 1 mL of undiluted stearoyl chloride was placed in a flat tray. A coating roller ("DIALL", Kingfisher International Products Ltd., London, UK) was impregnated with stearoyl chloride by rolling the coating roller at the bottom of the flat tray. The coating roller was a rotating cylinder having a diameter of 40 mm and a length of 100 mm and having a filamentary element made of mohair having an average length of 5 mm. The impregnation was homogenized by rolling the roller at the bottom of a flat container, thereby transferring all the stearoyl chloride to the coating roller. A plurality of square disposable paper towels (21 cm x 21 cm) were selected. Kimberly Clark Company). Each disposable tissue is formed by four stacked paper layers, each layer having 0.5g (11g / m 2) of about mass. Stearoyl chloride is deposited on one of the main faces of the first paper towel (referred to as the paper towel to be acylated) of a plurality of disposable paper towels by rolling a roller that is in full contact with one of the two faces of the first paper towel and by applying a moderate pressure suitable for partially squeezing the filamentary element of the roller to the coating roller. For this reason, a substantially vertical force in a top-to-bottom direction is applied to the roller, and the force has a value between about 5N and about 20N, while ensuring that the paper towel will not be deteriorated. Therefore, the stearyl chloride impregnated on the coating roller is continuously deposited on one face (referred to as the deposition face) of each paper towel of a plurality of paper towels to be acylated, without reloading the coating roller. After the stearyl chloride is deposited, the original disposable paper towel referred to as the exposed paper towel is placed on the face opposite to the deposition face of each paper towel to be acylated, and each assembly formed by the paper towel to be acylated covered with the corresponding exposed paper towel is introduced into a ventilated oven at 150 ° for 2 minutes. Each pair of paper towels formed by the paper towel to be acylated and the corresponding exposed paper towel is taken out from the ventilated oven. After cooling, the hydrophobicity of the deposited face of the tissue to be acylated and the hydrophobicity of the face opposite to the deposited face were analyzed. The hydrophobicity of the exposed tissue was also analyzed. It was observed that both sides of the tissue of a plurality of successively impregnated tissues had high hydrophobicity, which was shown by a constant contact angle of 150° with water over the entire surface of the tissue. The hydrophobicity of the exposed tissue was initially high, indicating that the amount of stearoyl chloride deposited on the first tissue in the order of its impregnation was greater than the maximum amount of stearoyl chloride that could be grafted onto such a tissue. However, it was observed that this hydrophobicity decreased with the impregnation placement of the tissue and became non-uniform. This indicates that the roller was loaded with less and less reactants. The continuous impregnation of the tissues in series made it possible to obtain acylated tissues with excellent hydrophobicity and at the same time low hydrophobicity for the corresponding exposed tissue. In this case, the roller was optimally loaded with stearoyl chloride. It was observed that the deposition of stearoyl chloride on a large number of tissues could continue without a significant decrease in the hydrophobicity obtained.

[0116] Example 2 - Quantification

[0117] The tissue was weighed with a precision balance before and after the deposition of the stearoyl chloride using a roller optimally loaded with stearoyl chloride as described in Example 1. A value of 1 mg of stearoyl chloride per face was found on average. When stearoyl chloride was deposited on both faces, a value of 2 mg was found. The amount of stearoyl chloride deposited was about 45 mg / m 2 Solid material; the hydrophobic properties are excellent without the use of pentane-type non-polar solvents.

[0118] Example 3 - Reproducibility

[0119] After carrying out the first deposition of stearoyl chloride and determining the amount deposited by weighing, the operation was repeated 4 times, weighing the tissue each time. It was observed that each deposition of stearoyl chloride resulted in an additional increase of 1 mg. Thus, an amount of 5 mg was deposited. This example shows that the deposition of stearoyl chloride by means of a roller is reproducible.

[0120] Example 4 - Optimization of Roller Load

[0121] The operation of the loading roller in Example 1 was repeated, depositing with stearoyl chloride but without applying the exposed paper towel. After one minute in the oven at 150°C, the door was opened. During the heating of the first paper towel, condensation mist was observed. Then, this gradually decreased with the treated paper towel. When it was observed that the condensation mist almost disappeared, the hydrophobicity of the paper towel was tested, and it was observed that the surface on which the stearoyl chloride was deposited had a very high hydrophobicity and a contact angle of 150°. When the roller loading operation was implemented with 1 mL of stearoyl chloride, the first paper towel among the multiple paper towels to be acylated on which the roller was continuously applied and which did not cause the formation of condensation mist was placed near the 30th time.

[0122] Example 5 - Impermeability

[0123] The impermeability of the acylated disposable tissue was demonstrated by hanging each square disposable tissue by its four corners and by pouring a certain amount of water (10 mL) into the tissue bag thus formed. The acylated disposable tissue bag prepared with the optimally loaded roller described in Example 1 was completely impermeable to water for more than 4 days.

[0124] Example 6 - Comparative Example (outside the present invention)

[0125] Prepare 100 mL of a 0.05% solution of stearoyl chloride in anhydrous pentane to soak 10 square disposable paper towels (21 cm x 21 cm) Kimberly Clark Company), each disposable paper towel retains about 5 μl of stearoyl chloride. Pentane is eliminated by spontaneous evaporation under a suction hood with dry air having a moisture content of less than about 20%. The step of distributing stearoyl chloride on the disposable paper towel according to the invention is not implemented. Next, one of the disposable paper towels is placed in a ventilated oven at a temperature of 150°C. The reaction is allowed to proceed for 2 minutes. After opening the door of the ventilated oven, no formation of a condensation mist of free stearoyl chloride is observed. The disposable paper towel obtained is hydrophobic and impermeable to water. A drop of 200 μL of distilled water is deposited on the surface of one of the acylated disposable paper towels. The water drop remains formed on the surface of the paper towel without spreading. The contact angle has a value close to 150°, demonstrating the correct grafting efficiency. The original paper towel (called exposed paper towel) is placed on top of the second paper towel prepared as above, and the assembly is placed in a ventilated oven at 150°C for 2 minutes. The exposed paper towel is tested with respect to its hydrophobicity and it is observed that this is very low. These two results confirm the fact that good hydrophobicity values ​​are obtained without excess stearoyl chloride when applying appropriate but very small amounts using the pentane impregnation method. The present invention aims to obtain such hydrophobicity values ​​without the use of organic solvents.

[0126] Example 7 - Comparative Example (outside the present invention)

[0127] Solutions of 0.05%, 0.1% and 0.5% stearyl chloride in petroleum ether 100 / 150 were prepared. Paper towels were impregnated with these different solutions and also with controls produced with pure solvent, most of the solvent was allowed to evaporate and the paper towels were then placed in an oven at 150°C for 2 minutes. The door of the oven was then opened and in all cases the formation of condensation mist was observed. This mist was greater in the case of the 0.5% solution and less in the case of the solvent alone. These results indicate that when petroleum ether 100 / 150 is present alone, it remains trapped in the fibers of the paper material and that it is associated with the reactants when the reactants are in excess. It was observed that it was necessary to continue heating in the oven for another additional 2 minutes so that the presence of condensation mist was no longer observed when the door was opened.

[0128] The contact angle values ​​of various samples were determined, and it was observed that the values ​​obtained for 0.05% and 0.1% were 100° and 120°, respectively, while the value obtained for 0.5% was about 150°. The experiment was repeated with the exposed tissue. A high hydrophobicity was observed for 0.5%, but a significant hydrophobicity was also observed for 0.05% and 0.1%. These results indicate that the presence of residual solvents disrupts the correct implementation of the chromogenic acylation reaction.

[0129] Example 8 - Acylation treatment according to the invention - Brushing method.

[0130] A coating roller "Diall" with dimensions of 4×10 cm and having a thread-like element made of mohair, previously loaded with 1 ml of stearic acid chloride, is attached to a rod which is then mounted on an adjustable variable speed electric drill. The rotating coating roller is then moved close to the disposable tissue to be treated so that the free end of the thread-like element of the coating roller brushes the surface of the tissue. This is done so as not to deteriorate the structure of the tissue. The procedure of Example 1 is then followed. Fatty acid chlorides are deposited successively on the tissues of a series of disposable tissues until the best hydrophobic properties are obtained on the face on which the fatty acid chloride is deposited and low hydrophobicity is obtained on the face opposite to the deposition face. The tissues are weighed before and after deposition. Values ​​of 1 mg of acid chloride per face are obtained, which are equivalent to those deposited by a roller according to the method described in Example 1. The thread-like elements of the velvet have a degree of freedom which enables them to slide on the surface of the tissue and is suitable for an efficient transfer of fatty acid chlorides to the surface of the tissue.

[0131] Example 9 - Reloading of Rollers

[0132] The coating rollers initially loaded with 1 mL of fatty acid chloride (as described in Example 1) and used to coat paper material are eventually used up after the fatty acid chloride has been deposited on a large amount of paper material. Reloading is performed by depositing 50 μl of fatty acid chloride at the bottom of the deposition container and by allowing the coating roller to absorb this amount of fatty acid chloride. These reloaded coating rollers behave like new rollers loaded with 1 mL of reactant. These results are consistent with the measurement of the amount of reactant deposited by direct weighing.

[0133] Example 10 - Depth / Surface Distribution

[0134] Stearoyl chloride was applied to a disposable paper towel comprising four related layers superimposed. After stearoyl chloride was applied to one of the main faces of the paper towel (layer 1) by one or other of the methods described in Examples 1 or 8 above, the layers were separated and placed in an oven. It was observed that the first layer (layer 1) was highly hydrophobic, but the results were different depending on the deposition method. By applying according to the method described in Example 1, it was observed that layer 2 was hydrophobic, and layer 3 was also hydrophobic, but to a lesser extent. By applying according to the method described in Example 8, only layer 1 was highly hydrophobic. These results indicate that the reactants are able to penetrate more or less into the thickness of the paper as a function of the deposition method. The method described in Example 1 enables the fatty acid chloride to penetrate deeper, while the method described in Example 8 enables surface-limited deposition.

[0135] Example 11 - Reactant Transfer.

[0136] Kitchen roll paper sheets were selected as solid materials which had been loaded using a coating roller reloaded with fatty acid chloride according to the method described in Example 8 above, so as to deposit the fatty acid chloride mainly on the surface of the kitchen roll paper. An untreated roller was now used and applied to the paper according to one of the methods described in Examples 1 and 8. Next, these rollers were used to coat the original paper. After coating, the papers were placed in an oven at 150° C. for 1 minute and tested for their hydrophobicity. It was observed that the papers coated according to the method described in Example 8 were more hydrophobic than those coated according to the method described in Example 1. The method described in Example 8 was more effective than the method described in Example 1 in the method for recovering the reactants at the surface of the first coated paper and transferring them to another paper. These results show that the two deposition methods are not equivalent. The method described in Example 1 tends to allow the reactants to penetrate deeply into the thickness of the paper, while the method described in Example 8 allows the fatty acid chloride to spread more superficially.

[0137] Example 12 - Distributing Temperature

[0138] The coating roller was optimally loaded with fatty acid chloride according to Example 1. The paper was continued to be coated with the roller by placing the paper at a temperature of 60° C. according to the method described in Example 1 or according to the method described in Example 8 without reloading. It was observed that the hydrophobicity of the paper coated at 60° C. was better than that carried out at ambient temperature. These results indicate that the reactant transfer efficiency is better at higher temperatures.

[0139] Example 13 - Thermal Deposition

[0140] According to Example 1, a coating roller is optimally loaded with fatty acid chloride. A paper towel is placed in an oven at 160° C. and allowed to reach thermal equilibrium. The door of the oven is then opened and the fatty acid chloride is deposited directly onto the hot paper towel inside the oven with a coating roller. No condensation mist is observed during deposition. The paper towel is then removed from the oven and tested for its hydrophobicity. It is excellent, with a clear water repellency. This experiment shows that the deposition of fatty acid chloride can be carried out at high temperatures corresponding to the conditions of the color development reaction. Deposition and reaction are actually carried out simultaneously. An additional advantage of this high temperature deposition is that it makes it possible to eliminate at least a portion of the water contained in the paper (which may lead to partial hydrolysis of the fatty acid chloride) and to carry out the acylation under essentially anhydrous conditions.

[0141] Example 14 - Behenyl chloride

[0142] Palmitoyl chloride and behenoyl chloride were used as reactants. Good results were obtained in both cases. The hydrophobicity imparted by palmitic acid was low, while the hydrophobicity imparted by behenic acid was excellent.

[0143] Example 15 - Oleophilic Velvet Roller and Oleophobic Velvet Roller

[0144] Comparative tests were conducted on the distribution of fatty acid chlorides on paper materials:

[0145] - using a coating roller formed of oleophilic velvet according to the invention; and

[0146] - using a coating roller formed from the oleophobic fleece according to the invention, wherein the filamentary elements are coated with

[0147] The paint roller with oleophobic velvet requires the elimination of excess fatty acid chloride unevenly distributed on the paint roller surface before deposition, but the deposition of residual fatty acid chloride gives excellent results in terms of hydrophobicity.

[0148] Example 16 - Polyvinyl alcohol (PVA)

[0149] Use a paint roller to apply 100mg / m 2 10 g of stearyl chloride was applied to a paper coated with 10 g of PVA 2899 having an average molecular weight of 145 000. The paper was placed in an oven at 150°. After one minute, the door was opened and no formation of condensation mist was observed, indicating that there was no significant excess of reactants. The hydrophobicity of the paper was then tested and proved to be absolutely water-repellent.

[0150] Example 17 - Comparative Test - Foam Roller (Outside the Invention)

[0151] The foam roller was loaded with 1 ml of fatty acid chloride. The load of the foam roller was homogenized by rolling. The roller was applied to the kitchen roll paper. After passing through an oven at 150°, the hydrophobicity of the kitchen roll paper was analyzed. It was observed that the hydrophobicity was irregular. The kitchen roll paper had hydrophobic and non-hydrophobic areas. The foam roller did not allow the fatty acid chloride to be distributed on the kitchen roll paper, thus enabling the kitchen roll to have impermeability.

[0152] In addition to those described above, the present invention may have many variations and applications. In particular, it goes without saying that, unless otherwise indicated, the different structural and functional features of each of the above-mentioned embodiments should not be considered to be combined with each other and / or closely and / or inseparably linked together, but rather, they are simply juxtaposed. In addition, the structural and / or functional features of the above-mentioned different embodiments may be in any other juxtaposition or any other combination, in whole or in part.

Claims

1. A method for acylation of solid materials (3, 9) carrying hydroxyl (-OH) groups, called reactive hydroxyl groups, which are accessible and capable of reacting with gaseous fatty acid chlorides, wherein: - distributing at least one fatty acid chloride (1) at least on the surface of the solid material (3, 9) using a distributor device (2), the distributor device having an application surface suitable for depositing the at least one fatty acid chloride (1) from the application surface at least on the surface of the solid material (3, 9); - heating the at least one fatty acid chloride (1) distributed at least on the surface of the solid material (3, 9) at a temperature below the vaporization temperature of the at least one fatty acid chloride (1), called the acylation temperature, so as to acylate the solid material (3, 9) by reaction of the at least one fatty acid chloride (1) in the gaseous state with at least one of the reactive hydroxyl groups of the solid material (3, 9), and; - directing a flow of a gaseous composition (6) at said acylation temperature onto said solid material (3, 9) so as to entrain at least a portion of the gaseous hydrochloric acid (7) formed by the acylation reaction; Characterized in that the application surface of the dispenser device (2) is velvet provided with velvet thread-like elements which are non-reactive with respect to the at least one fatty acid chloride (1) and are suitable for: o absorbing the at least one fatty acid chloride (1) by contacting with the at least one fatty acid chloride, and; o releasing the at least one fatty acid chloride by contacting the filamentary elements of the velvet with the solid material (3, 9); The distribution steps (12, 14) are carried out so that the at least one fatty acid chloride (1) is concentrated to 20 mg / m 2 Up to 1 g / m 2 The amount between the surface areas of the solid materials (3, 9) is distributed on the solid materials (3, 9).

2. The method according to claim 1, characterized in that The at least one fatty acid chloride is distributed at least on the surface of the solid material by brushing the free longitudinal ends of the velvet filamentary elements of the application surface onto the surface of the solid material.

3. The method according to claim 1, characterized in that The distributor device comprises at least one application roller having the application surface, the at least one application roller being rotatably mounted relative to the solid material, and wherein the at least one fatty acid chloride is distributed by rotating the at least one application roller with the application surface in contact with the solid material.

4. The method according to claim 3, characterized in that said solid material is in the form of a strip moving in a running direction parallel to the largest dimension of the strip, between a reel upstream of said strip of acylated solid material and a take-up roller downstream of the strip; - said at least one fatty acid chloride is continuously deposited on at least one free surface of said mobile solid material, and; - said at least one fatty acid chloride deposited on the surface of said solid material is distributed at least on the surface of said solid material by means of said distributor device, and; - heating said solid material such that said at least one fatty acid chloride distributed at least on the surface of said solid material reaches said acylation temperature on said solid material, and; - directing the stream of the gaseous composition onto the solid material at the acylation temperature, thereby acylating the solid material.

5. The method according to claim 4, characterized in that The at least one acid chloride is deposited continuously on at least one free main surface of the solid material by means of a printing device.

6. The method according to claim 5, characterized in that The printing device is selected from the group formed by a flexographic printing device and a photolithographic printing device.

7. The method according to claim 3, characterized in that said solid material is in the form of a strip moving in a running direction parallel to the largest dimension of the strip, between a reel upstream of said strip of acylated solid material and a take-up roller downstream of the strip; - the at least one fatty acid chloride is continuously deposited on an application roller rotating in contact with the solid material, whereby the at least one fatty acid chloride is distributed from the rotating application roller at least on the surface of the solid material, and; - heating the solid material such that the at least one fatty acid chloride distributed at least on the surface of the solid material reaches the acylation temperature, and; - directing a stream of the gaseous composition onto the paper material at said acylation temperature.

8. The method according to claim 7, characterized in that The at least one fatty acid chloride is deposited on the rotating applicator roller by bringing the rotating applicator roller into contact with an anilox roller of a printing unit loaded with the at least one fatty acid chloride.

9. The method according to claim 1, characterized in that The velvet filamentary elements are formed of at least one material selected from the group consisting of keratin fibers, polyester fibers, polyamide fibers, acrylic fibers, fluorinated fibers, fibers provided with a fluorinated coating, microfibers, ultramicrofibers and supermicrofibers.

10. The method according to one of claims 1 to 3, characterized in that The at least one acid chloride is deposited on the surface of the solid material by means of a dispenser device having an application surface previously loaded with the at least one fatty acid chloride.

11. The method according to claim 10, characterized in that The solid material is a disposable paper towel.

12. The method according to one of claims 1 to 8, characterized in that The velvet filamentary elements have a length between 1 mm and 10 mm.

13. The method according to one of claims 4 to 8, characterized in that The rotatable application roller is rotated at an angular rotational speed selected so that the free end of the velvet filamentary element is rotated at a linear speed having a value different from the value of the running speed of the solid material.

14. The method according to one of claims 4 to 8, characterized in that The rotatable application roller is rotated in a selected direction of rotation so that the free ends of the velvet filamentary elements are moved counter to the movement of the strip of solid material.

15. The method according to one of claims 4 to 8, characterized in that The rotatable application roller is rotated in a selected direction of rotation so that the free ends of the velvet filamentary elements move in the same direction as the movement of the solid material.

16. The method according to one of claims 1 to 8, characterized in that The velvet filamentary elements have a flexibility selected so as not to damage the solid material upon contact with the solid material.

17. The method according to one of claims 1 to 8, characterized in that The solid material has an outer surface layer formed of polyvinyl alcohol.

18. The method according to one of claims 1 to 8, characterized in that A composition comprising said at least one fatty acid chloride (1) and acetyl chloride, referred to as acylation composition, is distributed at least on the surface of said solid material.

19. The method according to one of claims 1 to 8, characterized in that The velvet filamentary elements are formed of at least one material selected from the group consisting of: aramid fibers, woven microfibers.

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