Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/25—Cellulose
  • D21H17/26—Ethers thereof
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
  • D21H17/55—Polyamides; Polyaminoamides; Polyester-amides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
  • D21H17/56—Polyamines; Polyimines; Polyester-imides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/18—Reinforcing agents
  • D21H21/20—Wet strength agents
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper

Definitions

• the present invention relates to the field of particularly security papers and in particular that of banknotes, produced from cellulosic fiber compositions and having to exhibit a high level of mechanical resistance in the wet state.
• Cellulosic cotton fibers are commonly used for the production of banknotes because they make it possible to provide these banknotes with very good mechanical performance, in particular high resistance to tearing and folding.
• the chemical reaction takes place between the carboxyl functions and the azetidinium function in a humid environment and in the presence of the cotton fibers considered for the manufacture of sheets.
• the sheet thus formed and dried to allow crosslinking of the immobilized resin is then advantageously provided with a three-dimensional network which is relatively resistant in the wet state.
• the object of the present invention is precisely to increase the potential for binding and fixing of this type of resins to a cellulosic fibrous network and thus to access an increased level of mechanical resistance, both in the wet and in the dry state, and advantageously with a significantly reduced unbound epichlorohydrin (PAAE) residual.
• PAAE epichlorohydrin
• the present invention also aims to reduce the ecological footprint of security documents.
• the present invention relates to a fibrous composition, in particular useful for the preparation of a sheet of paper, in particular of security, comprising at least
• said cellulosic fibrous material also having cellulosic fibers, called hemicellulose fibers, having a hemicellulose content of at least 18% by weight relative to to the total weight of said hemicellulose fibers, and a hemicellulose content of at least 0.7% by weight relative to the total weight of said cellulosic fibrous material.
• the composition according to the invention may be in wet form, in particular in the form of an aqueous suspension of fibers.
• composition according to the invention may be in dry form, in particular in the form of a fibrous substrate, in particular of paper type.
• the cellulosic fibrous material contains, as a source of hemicellulose, fibers chosen from sisal fibers, kenaf fibers and their mixtures, and preferably at least sisal fibers.
• Sisal fibers are advantageous in several ways.
• a fibrous composition according to the invention further comprises at least one intermediate carboxylated fixing agent.
• a fibrous composition according to the invention is of particular interest for the manufacture of sheets of paper, in particular security, more particularly banknotes, having high levels of wet strength and high breaking length.
• the present invention also relates to the use of a fibrous composition according to the invention for preparing a sheet of paper, in particular security.
• the invention relates to a sheet of wet-resistant paper comprising a fibrous composition according to the invention.
• a wet-resistant security sheet comprising a fibrous composition according to the invention.
• the invention relates to a security and / or valuable document comprising a sheet of paper according to the invention.
• FIG 1 represents the breaking length in the dry state for four compositions according to the invention comprising 20% by weight of sisal fibers relative to the weight of fibrous material (B, D, E and F) and a composition without invention in which the fibrous material is composed only of cotton fibers (G).
• FIG 2 represents the length at break in the wet state for four compositions according to the invention comprising 20% by weight of sisal fibers relative to the weight of fibrous material (B, D, E and F) and a composition without invention in which the fibrous material is composed only of cotton fibers (G).
• the first subject of the present invention is a fibrous composition, in particular useful for the preparation of a sheet of paper, in particular of security paper, comprising at least - a fibrous cellulosic material based on cotton fibers and devoid of wood fibers, and
• said cellulosic fibrous material also having cellulosic fibers, called hemicellulose fibers, having a hemicellulose content of at least 18% by weight relative to to the total weight of said hemicellulose fibers, and a hemicellulose content of at least 0.7% by weight relative to the total weight of said cellulosic fibrous material.
• the cellulose compositions according to the invention have the advantageous characteristics of having, when they are in dry form and in the sheet state, an improved breaking length, more particularly in a humid environment.
• the fibrous composition according to the invention comprises at least one fibrous material which comprises preferably natural cellulosic fibers.
• the cellulosic fibrous material according to the invention is only formed from natural cellulosic fibers.
• the fibrous material according to the invention has the originality of having a hemicellulose content by weight of at least 0.7% relative to its total weight and in particular of comprising hemicellulose fibers.
• the inventors have in fact observed that this specific type of cellulose is found to be capable of interacting directly with a wet strength agent endowed with reactive functions with respect to free carboxylic functions.
• these reactive functions are azetidinium functions and the agent for resistance to the wet state is chosen from epichlorohydrin resins (PAAE).
• the presence of an adjusted amount of hemicellulose in the fibrous material advantageously makes it possible to immobilize an increased amount of wet strength agent and therefore significantly increases the mechanical properties without altering the moisture resistance properties of the materials. corresponding fibrous materials.
• This predisposition, obtained according to the invention, of the fibrous material to be immobilized directly by itself with a wet strength agent is also advantageous from an economic point of view.
• a fibrous material according to the invention a significant reduction in the amount of residual wet strength agent, that is to say not having does not interact, compared to a fibrous material devoid of hemicellulose.
• this reactivity of the fibrous material with respect to a wet strength agent in accordance with the invention makes it possible to consider a smaller amount of carboxylated fixing agent, which is conventionally required to immobilize a fixing agent. wet strength on a fibrous material not in accordance with the invention.
• the level of hemicellulose in the cellulosic fibrous material varies from 0.7% to 4%, and preferably from 1% to 4%, by weight of hemicellulose relative to the total weight of the cellulosic fibrous material.
• the hemicellulose required in the cellulosic fibrous material according to the invention is at least partly present therein in the form of so-called hemicellulose fibers.
• hemicellulose fibers are cellulosic fibers having a hemicellulose content of at least 18% by weight relative to their total weight or even preferably of at least 21% by weight relative to their total weight. to their total weight.
• the hemicellulose fibers suitable for the invention can in particular be chosen from fibers of esparto, kenaf, jute, flax, sisal, kapok and their mixtures.
• the hemicellulose fibers are chosen from sisal fibers, kenaf fibers, jute fibers, kapok fibers and their mixtures.
• the hemicellulose fibers are chosen from sisal fibers, kenaf fibers, jute fibers and their mixtures and preferably from sisal fibers, kenaf fibers and their mixtures.
• the kenaf fibers are in particular characterized by an alpha-cellulose content by weight ranging from 31% to 39% and a hemicellulose content ranging from 21% to 23% relative to their total weight. They are therefore very particularly suitable for being used in the cellulosic fibrous material.
• Kapok fibers are characterized in particular by an alpha-cellulose content by weight ranging from 35 to 64% and a hemicellulose content ranging from 22 to 26% relative to their total weight. They are therefore very particularly suitable for being used in the cellulosic fibrous material.
• sisal fibers they advantageously have a weight content of hemicellulose ranging from 21% to 24% relative to their total weight for a weight content in alpha-cellulose ranging from 43% to 56% relative to their total weight. Besides this particularly high content of hemicellulose which makes them particularly advantageous as a source of hemicellulose in the context of the invention, sisal fibers also have other advantages.
• sisal fibers exhibit a morphological similarity to cotton fibers. They are therefore particularly suitable for replacing cotton fibers without loss of performance for sheets of paper, in particular security paper formed with such a composition.
• the sisal fibers therefore allow a double positive interaction, physicochemical and morphological, with the resins used as resistance agent in the wet state.
• sisal fibers are also very advantageous for their low environmental footprint. Indeed, the cultivation of sisal requires little water, fertilizers or phytosanitary products, and its waste can be recovered (biogas, pharmaceutical ingredients, construction material, fertilizer, animal feed). In addition, sisal fibers are particularly available as a local raw material in countries such as Brazil, Africa, Kenya, Madagascar and China.
• sisal fibers mention may be made of the sisal fibers marketed by SWM, or else the CELA VE C ECF, CELA VE E TCF or CELA VE D TCF fibers marketed by the company CELESA.
• the fibrous material considered in the compositions according to the invention comprises as hemicellulose fibers at least sisal fibers, or even only sisal fibers, these sisal fibers being obtained in particular from sisal pulp. whitened.
• the fibrous material of the invention contains at least cotton fibers.
• Cotton fibers are indeed efficient fibers in terms of mechanical strength performance, in particular burst strength and tear strength.
• the cellulosic fibrous material comprises at least 50%, preferably at least 80% and more preferably from 80% to 95%, by weight of cotton fibers relative to its total weight.
• the cotton fibers can be chosen from fibers of “combers” type, of “linters” type or a mixture thereof.
• the fibers of the “combers” type are long fibers obtained by means of combing machines.
• the fibers of the “linters” type are cellulose fibers originating from the short hairs of the cotton flower.
• the cellulosic fibrous material comprises cotton fibers in the form of a mixture of fibers of “combers” type and / or of “linters” type, for example in a weight ratio of between 40/60 and 60/40, in particular in a weight ratio of 50/50.
• the fibrous material according to the invention may contain, in addition to cotton fibers and hemicellulose fibers, ancillary fibers chosen in particular from bamboo fibers, abaca fibers and their mixtures.
• the fibers constituting the fibrous material of the invention can be obtained from bleached, semi-bleached or unbleached pulps, in particular bleached.
• composition according to the invention further comprises at least one wet strength agent.
• This type of agent is instrumental in increasing the wet mechanical properties of the paper.
• thermosetting polymers which are added when the paper is still wet and which crosslink in the paper upon drying.
• the wet strength agents suitable for the invention are compounds having one or more reactive functions with respect to the carboxylic functions provided in the fibrous material by the cellulose fibers with hemicellulose.
• these reactive functions are azetidinium functions.
• the resistance agent comprises at least or even consists of one or more resins chosen from resins based on polyamide polyamine epichlorohydrin (PAAE).
• the resistance agent preferably a polyamide polyamine epichlorohydrin resin, having interacts with the carboxylic functions of the hemicellulose and therefore immobilized at the level of the fibrous material, undergoes during the temperature drying of the composition according to the invention a crosslinking which generates a cohesion between the fibers thus significantly reinforcing the mechanical properties in the dry or wet state of the dry composition by the development of strong covalent bonds, and in particular its resistance in terms of breaking length.
• a crosslinking which generates a cohesion between the fibers thus significantly reinforcing the mechanical properties in the dry or wet state of the dry composition by the development of strong covalent bonds, and in particular its resistance in terms of breaking length.
• this improvement in mechanical properties is also advantageously correlated with a significant reduction in the amount of free resistance agent, that is to say of free resin, after crosslinking.
• This characteristic results in the manifestation of a zeta potential and a lower ionic demand by the fibrous material treated.
• the ionic demand is measured by titration using an electrolyte: a specific quantity of a filtrate is neutralized by an electrolyte, and at the neutralization point, the quantity of electrolyte used is the value of the demand. ionic.
• hemicellulose fibers makes it possible to immobilize an increased amount of resistance agent and therefore to decrease the level of non-immobilized resistance agent.
• This effect is beneficial in several ways. Indeed, when the resistance agent is not immobilized, and therefore remains in free form in the final fibrous material, it is on the one hand ineffective in increasing the mechanical resistance of this material and, on the other hand, constitutes a residual ionic pollution in the medium and also a loss of material.
• a fibrous composition according to the invention may contain from 1% to 10% by dry weight, preferably from 1% to 5% by dry weight, and more preferably from 1.5% to 4% by weight of agent. (s) of wet strength relative to the dry weight of fibers.
• the fibrous composition of the invention further comprises at least one intermediate carboxylated fixing agent.
• Such an agent also contributes to the cohesion of the fibrous composition.
• the fixing agent is chosen from polymers comprising carboxylic functions.
• it is chosen from guar gums, cellulose derivatives and their mixtures, in particular from carboxylated cellulose derivatives.
• the fixing agent comprises at least one carboxymethyl cellulose (CMC), or even consists of one or more carboxymethyl cellulose.
• the content of intermediate fixing agent in the fibrous composition comprising hemicellulose according to the invention can be reduced compared to a fibrous composition whose fibrous material comprises less than 0.7% by weight of hemicellulose.
• a fibrous composition according to the invention may further comprise at least one filler, in particular inorganic.
• these fillers are intended in particular to increase the opacity, the whiteness and / or the printability of said fibrous substrate.
• the filler can be chosen from mineral fillers, in particular calcium carbonate, kaolin, titanium dioxide, talc, silicas, hydrated aluminas, aluminum silicates and their mixtures, and / or from organic fillers. , in particular plastic fillers or pigments.
• the fibrous composition comprises at least titanium dioxide.
• Additives or adjuvants commonly used in the papermaking field can also be used in a fibrous composition in accordance with the invention.
• additives for example, pigments and dyes, anti-microbial, anti-foaming and retention agents, in particular for retention of charges, or else tracers.
• a fibrous composition according to the invention can also comprise synthetic fibers.
• the presence of synthetic fibers, mixed with cellulosic fibers, in the fibrous composition can make it possible to improve the properties of resistance to tearing and to folding of said substrate.
• a fibrous composition can be in a wet form, in particular in the form of an aqueous suspension.
• Such a fibrous composition can be used in a process for preparing a substrate, usually used in the papermaking field, in particular in a papermaking process.
• the fibrous composition may also be in a dry form.
• the fibrous composition may also be in the form of a fibrous substrate of the paper type, preferably of the bank paper type.
• a fibrous substrate, in particular of paper type can be produced from the fibrous composition in the form of an aqueous suspension, in particular by draining, pressing and drying.
• additional steps can be implemented depending on the desired fibrous substrate properties.
• a dry fibrous composition according to the invention can also be combined with a surface treatment of antifouling type, in particular hydrophobic and / or oleophobic, suitable for the use to which the corresponding paper material is dedicated.
• a paper material in accordance with the invention can be surface treated to form laminated or film-coated papers, for example those considered for food packaging, and / or can be provided with an anti-fouling treatment by impregnation, surfacing, coating and / or varnishing.
• a dry fibrous composition according to the invention can also be combined with an antimicrobial surface treatment, in particular antibacterial, antifungal, antiviral and / or anti-yeast, for example by impregnation, surfacing, coating and / or varnishing.
• an antimicrobial surface treatment in particular antibacterial, antifungal, antiviral and / or anti-yeast, for example by impregnation, surfacing, coating and / or varnishing.
• the present invention also relates to the use of a fibrous composition as described above for preparing a sheet of paper, in particular security.
• the sheet of paper, in particular of security can in particular be prepared by transformation, in particular by cutting, printing and / or varnishing, of the fibrous substrate mentioned above.
• This sheet of paper can in particular be characterized in that it forms a security sheet.
• the sheet of paper according to the invention comprises by mass at least:
• the combination according to the invention proves to be particularly advantageous in terms of the paper thus formed because the hemicelluloses required according to the invention have carboxyl groups which will intervene during the flocculation and thus make it possible to obtain a network (polymer (s), hemicellulose fibers and cotton fibers) with improved cohesion.
• an anionic polymer is a polymer carrying negative charges. It can be derived from the anionic functionalization of so-called neutral polymers because they are uncharged.
• Anionic polymers suitable for the invention have a glass transition temperature above -40 ° C.
• glass transition temperature is understood to mean the temperature below which the polymer is rigid. As the temperature increases, the polymer goes through a transition state which allows the macromolecular chains to slide relative to each other and the polymer softens.
• this anionic polymer is a polymer having carboxylated functions.
• a polymer is obtained by homopolymerization of at least one monomer or copolymerization of at least two monomers chosen from acrylic acid, methacrylic acid, acrylonitrile, acrylate. alkyl, alkyl methacrylate, acrylamide, methacrylamide, N-methylol acrylamide, styrene and butadiene.
• the anionic polymer is chosen from acrylic homo- and co-polymers, acrylate homo- and co-polymers, carboxylated styrene-butadiene copolymers and mixtures thereof.
• acrylic copolymers the following may be mentioned in particular:
• said polymer is a carboxylated styrene-butadiene copolymer.
• Such copolymers are available, for example, from The Dow Chemical Company with various glass transition temperatures.
• this anionic polymer can also be non-carboxylated.
• anionic polymers By way of representative of these other forms of anionic polymers, mention may be made of the anionic forms of polyacrylamides and of polystyrene co-polymers, such as in particular styrene-butadiene copolymers.
• the anionic polymer has a Tg greater than 23 ° C.
• the polymer (s) having a glass transition temperature greater than 23 ° C are chosen from polyacrylics, poly acrylates, polyacrylamides, anionic forms of polystyrenes, polyvinyls, polyethylenes, polyurethanes, and their mixtures.
• the polymer (s) exhibiting a glass transition temperature greater than 23 ° C. are chosen from acrylic (or polyacrylic) polymers, that is to say homopolymers or copolymers comprising at least minus one acrylic monomer, namely acrylic homopolymers or acrylic copolymers.
• acrylic copolymers there may be mentioned in particular:
• the polymer (s) exhibiting a glass transition temperature greater than 23 ° C. are chosen from acrylic homopolymers.
• Such polymers are available in anionic dispersion, for example:
• the anionic polymer (s) can be non-crosslinkable, crosslinkable using an external crosslinker or even self-crosslinkable.
• anionic polyurethane of the anionic forms of polyurethane-polyesters, polyurethane-polyethers and polyurethane-polycarbonates, and their mixtures.
• the anionic polymer (s) is generally used in an amount of 1% to 20% by dry weight, preferably from 1% to 10% by dry weight, and more preferably from 3% to 8% by dry weight of anionic polymer (s), relative to the dry weight of fibers.
• a sheet of paper according to the invention may further comprise an effective amount of at least one cationic precipitating agent.
• This cationic precipitating agent by modifying the electrostatic charge of the anionic cellulose fibers, allows, among other things, the attachment of the particles of the anionic polymer (s) to the fibers.
• the cationic precipitating agent is chosen from polyaluminum chlorides, cationic polymers soluble in water, in particular from cationic starches, polyamides, polyacrylamides, polyethyleneimines, polyvinylamines and mixtures thereof.
• the compounds considered according to the invention as a wet strength agent are likely to also have this ability to precipitate said anionic polymer at the surface of the fibers.
• This is particularly the case with polyamide-poly amine-epichlorohydrin resins, known as PAAE resins, which are very particularly suitable for the invention as a wet strength agent.
• PAAE resins polyamide-poly amine-epichlorohydrin resins
• such a compound can perform both functions, provided that its amount is adjusted for its effectiveness.
• the amount of cationic precipitating agent is adjusted to allow almost all, preferably all, of the anionic polymer to be precipitated from the surface of the fibers. It varies in particular from 0.5% to 5% by dry weight, in particular from 0.8% to 3.5% by dry weight relative to the dry weight of fibers.
• a sheet of paper can comprise, in addition to the fibrous composition, at least one security element.
• This security element allows in particular the authentication of said sheet.
• said security element is chosen from visual devices, in particular optically variable devices, called OVDs, holograms, lenticular devices, elements with an interference effect, in particular iridescent elements, liquid crystals, pigments with an interference effect. magnetically orientable and multilayer interference structures.
• optically variable devices can be present on security threads integrated into the fibrous substrate or, on bands or patches affixed or printed on the fibrous substrate.
• said security element is chosen from so-called luminescent elements, revealable under UV or under IR, these luminescent elements possibly in the form of particles, fibrettes, boards, security thread integrated into the device. less in part in the fibrous substrate, bands or patches affixed or printed on the fibrous substrate.
• said security element is chosen from automatically detectable elements, in particular optically or magnetically, these detectable elements commonly called markers or taggants being integrated in the fibrous substrate or in visual or luminescent security elements.
• a sheet of paper, in particular security, according to the invention may also include a radio frequency identification device, called RFID, also providing an identification and traceability function to the sheet of paper, in particular security.
• RFID radio frequency identification device
• the present invention also relates to a security and / or valuable document comprising a sheet of paper according to the invention.
• the security and / or value document is a means of payment, such as a banknote, a payment card, a check or a restaurant ticket, an identity document, such as a credit card. identity, visa, passport or driving license, card, in particular access card, lottery ticket, transport ticket or even entry ticket to cultural or sporting events, loyalty card, a service card, a subscription card, a playing or collecting card, a voucher or a voucher.
• a banknote such as a banknote, a payment card, a check or a restaurant ticket
• an identity document such as a credit card. identity, visa, passport or driving license, card, in particular access card, lottery ticket, transport ticket or even entry ticket to cultural or sporting events, loyalty card, a service card, a subscription card, a playing or collecting card, a voucher or a voucher.
• a banknote is both a security document since it includes security elements, and a valuable document in the sense that it represents a value, unlike a ticket which can have a value. , in particular of exchange, without being secure. As for an access card, it can be secure but have no value, especially exchange.
• the security and / or value document according to the invention is a bank note.
• the security and / or value document according to the invention is a banknote comprising a varnish, in particular an overprint varnish.
• PAAE Polyamide polyamine epichlorohydrin
• CMC Carboxymethyl cellulose
• the zeta potential is measured with a “System Zeta Potential” device, model Mütek SZP-06 from the company BTG.
• the ionic demand is measured with a “Particle charge detector” device, model Mütek PCD-05 from the company BTG.
• wet break length or “wet break length”
• wet break length the length at which the sheets break under the effect of their own weight according to ISO 3781. 5.
• WRC Wet strength
• Dry burst strength (or “dry burst”) can be measured according to ISO 2758.
• dry burst index (or "dry burst index”) is the quotient of the dry burst strength, in kilopascals, divided by the basis weight of the paper determined in accordance with the standard. ISO 536.
• wet burst strength (or “wet burst”) can be measured according to ISO 3689.
• wet burst index is the quotient of the wet burst strength, in kilopascals, divided by the basis weight of the paper determined in accordance with the standard. ISO 536.
• Example 1 preparation of a fibrous substrate of paper type from compositions according to the invention and from a composition not in accordance with the invention
• the cotton fibers are first of all refined to reach a degree of refinement of 65 ° SR (Schopper-Riegler degrees), then mixed with the sisal fibers, in the case of the tests according to the invention, to form a suspension of fibers in water at a concentration of lg / L.
• the sisal fibers can also be refined before they are mixed with the cotton fibers, and / or the cotton and sisal fibers can be refined as a mixture.
• Titanium dioxide (T1O2), carboxymethyl cellulose (CMC), and PAAE resin are then added successively to the fiber suspension.
• the zeta potential of the fiber surface is measured for all compositions A to G of Example 1 following the mixing of all the components in the aqueous solution. The results are reported in Table 2 below. The zeta potentials of pure cotton and sisal pulp are also measured and are similar.
• compositions comprising sisal fibers (A to F)
• a negative zeta potential is measured, which reflects the fact that there is no longer any PAAE resin, of positive charge, free but that everything is fixed on the fibers.
• the zeta potential is positive. This phenomenon is confirmed by tests A to C which show that the zeta potential decreases when the sisal fiber content increases. There is therefore indeed a greater interaction of the PAAE resin with the sisal fibers compared to the cotton fibers.
• the breaking length is measured in the dry state and in the wet state for all the fibrous substrates of composition A to G of Example 1. The results are reported in Table 3 below and in Figures 1 and 2. .
• the break lengths, both dry and wet, of compositions comprising sisal fibers are greater than the break length of the test outside the invention (G). This result is valid for the different sisal fibers, but also for the different sisal fiber contents. Thus, the mechanical properties of fibrous substrates are improved both dry and wet by adding sisal fibers.
• Example 4 preparation of a surface paper from compositions according to the invention and from a composition not in accordance with the invention Two fibrous compositions and fibrous substrates are prepared according to the method described in Example 1 for the compositions of Table 4 below, according to the invention (H) and outside the invention (/).
• the fibrous substrates obtained then undergo surfacing in a size press with an aqueous composition comprising 4% PVA and 1% insolubilizer, to obtain a surfaced paper (“siz.ed paper” in English). English) followed by 20 min drying at 90 ° C.
• the blend of 50/50 comber / linter cotton fibers and Celave D sisal fibers have a zeta potential of -14.7 mV and -17 mV, respectively, measured in aqueous suspension at the same concentration.
• the zeta potentials of the different types of fibers are therefore of the same order of magnitude.
• the zeta potential (PZ) of the surface of the fibers is measured for compositions H and I of Example 4 for the successive additions of titanium dioxide, of CMC and of PAAE resin to the mixture of cotton fibers and, where appropriate, of sisal, in aqueous suspension at identical concentration.
• the final PZ is the PZ of the composition after addition of PAAE resin and before formation of the sheet.
• Example 2 The zeta potential is therefore hardly changed when adding T1O2, then drops sharply as expected when adding CMC.
• the addition of PAAE resin modifies the zeta potential in a distinct manner between the composition according to the invention and the composition outside the invention.
• the zeta potential remains negative, close to zero, which means that the composition no longer comprises free resin, and the majority of the negative sites are in interaction with the resin.
• the zeta potential is largely positive, signifying the presence of free resin in the composition.
• the final zeta potential approaches substantially zero, but remains largely positive in the case of comparative example /, and slightly negative for example H according to the invention.
• the PAAE resin is therefore not in excess in example H.
• Example 6 mechanical properties
• breaking and bursting lengths are measured for the surfaced papers obtained with the different compositions of Example 4 and reported in Table 6. [Table 6] All the properties of breaking and bursting length are improved, both in the dry state and in the wet state, by the addition of sisal fibers, as in test H according to the invention, by compared to the test / outside the invention devoid of sisal fibers.
• composition according to the invention comprising hemicellulose fibers, in particular sisal fibers, makes it possible to obtain a gain in strength, and in particular in wet strength.
• Example 7 Preparation of a fibrous substrate of paper type from compositions according to the invention and from a composition not in accordance with the invention
• Two fibrous compositions are prepared according to the method described in Example 1, one with 5% of the fibrous material formed of Celave C sisal fibers (test J according to the invention) and the other with 100% of the fibrous material formed of fibers cotton (test K outside the invention), the remainder being kept identical between the two compositions.
• the cotton fibers are formed from a 50/50 comber / linter mixture and the contents of PAAE, CMC and T1O2 are the same as for the compositions presented above.
• Example 8 zeta potential
• Example 7 The zeta potential is measured for the different compositions of Example 7:
• Example 9 Preparation of a fibrous substrate of paper type from compositions according to the invention and from a composition not in accordance with the invention
• Five fibrous compositions and fibrous substrates are prepared according to the method described in Example 1 for the compositions of Table 8 below, according to the invention (L, M and N) and outside the invention (O and P), by varying the resin content and the CMC content.
• compositions according to the invention make it possible to reduce the content of strength agent in the wet state, due to the presence of sisal fibers, while maintaining an REH and a wet breaking length. equivalent.
• the fixing of the PAAE resin on the sisal fibers rich in hemicellulose makes it possible to improve the mechanical properties of the fibrous substrate, in particular in the wet state, in compositions according to the invention.
• the presence of sisal fibers makes it possible to reduce the resin and / or CMC contents with minimal loss of performance, or even without loss of performance.
• Example 12 Preparation on a pilot machine of a paper-type fibrous substrate from compositions according to the invention comprising an anionic polymer
• Three fibrous materials comprising only cotton fibers (comber / linter weight ratio of 50/50) and Sisal fibers are prepared with proportions of Sisal fibers of 5%, 15% and 20% respectively.
• the fibrous compositions are formed by adding to each of these fibrous materials, suspended in water,
• PAAE resin a polyamide-polyamine-epichlorohydrin resin
• fibrous substrates are then prepared on a test paper machine (called a pilot machine) from the three fibrous compositions thus obtained.
• the fibrous substrates formed are then impregnated in a size press with an aqueous composition comprising 4% of PVA and 1% of insolubilizer, to obtain a surfaced paper (“sized paper” in English) followed by 20 min of drying at 90 ° C. .
• the wet strengths of the various substrates are shown in the table below.

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• 2020
  • 2020-07-02 FR FR2007003A patent/FR3112151B1/fr active Active
• 2021
  • 2021-07-01 EP EP21737689.6A patent/EP4176121B1/de active Active
  • 2021-07-01 WO PCT/EP2021/068269 patent/WO2022003139A1/fr active Application Filing
  • 2021-07-01 CN CN202180057136.4A patent/CN116507773A/zh active Pending
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