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
  • 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
  • D21H21/16—Sizing or water-repelling 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
  • 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
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/35—Polyalkenes, e.g. polystyrene
• • 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

• This invention relates to novel paper products, a process for the manufacture of such products by chemical treatment of paper, and a chemical formulation utilized in that process.
• the invention relates security paper products, eg banknotes.
• Paper has been used for centuries, mainly for three purposes. First, paper is used to record thoughts or ideas by way of printing and writing. Secondly, paper is used as packaging or as packaging articles such as labels or cartons and bags of paper. Thirdly, paper is also used as a medium of exchange in the form of printed currency, banknotes, cheques etc.
• Another coating process comprises laminating the paper with plastic films such as PNC, polyester, HDP etc.
• plastic films such as PNC, polyester, HDP etc.
• British Patent No 1095728 discloses surface treatment of materials with mixtures of polymers containing perfluorinated alkyl groups and any of a wide range of other polymers. Paper is one of the materials mentioned.
• a water-repellent and washable paper may be in the form of a security paper or banknote.
• a washable and water-repellent paper is meant a paper which is sufficiently water-repellent to survive exposure to moisture in normal usage and even a washing process.
• Such a paper is characterized by a very low degree of water absorption. This can be expressed in terms of the parameter known as the Cobb value. Papers in accordance with the invention may have Cobb values of between 0.01 and 20, more preferably of between 0.01 and 15, and particularly between 0.01 and 10. This is in contrast with papers conventionally used for security papers such as banknotes, for which the Cobb value is typically 50 or more. Despite the very low water absorption and Cobb value of the paper according to the invention, the paper is nonetheless printable, as well as having other advantageous properties such as improved tensile strength, wet strength and "burst factor". Consequently, the products may be more durable than conventional papers and increased lifetime.
• a process for the manufacture or treatment of paper or a paper product comprises applying to the paper or paper product, either during manufacture or subsequently, a solution or dispersion of a rubber in an organic solvent or mixture of solvents, the solution or dispersion being at least substantially free of polymers containing perfluorinated alkyl groups.
• the process according to the invention is advantageous in that the paper produced by the process has the improved properties referred to above, notably reduced, water-absorbing characteristics compared with conventional papers.
• the invention provides a paper or paper product prepared by the process described above.
• the product may be a security paper or banknote.
• a chemical formulation for use in the manufacture or treatment of paper or paper products comprising a solution or dispersion of a rubber in an organic solvent or mixture of solvents, the solution or dispersion being at least substantially free of polymers containing perfluorinated alkyl groups.
• substantially free of polymers containing perfluorinated alkyl groups is meant that the solution or dispersion contains no such polymers or contains very little of such polymers, eg less than 1 % w/w, or more preferably less than 0.1% w/w. Preferably, the formulation is free of such polymers.
• the rubber may be a natural rubber, but is preferably a synthetic rubber.
• the synthetic rubber is preferably a polymer of butadiene or a substituted derivative thereof.
• the synthetic rubber may be a homopolymer or may be a block or random copolymer of the butadiene or derivative thereof with another monomer.
• a particularly preferred synthetic rubber is that known as neoprene, ie polychloroprene (2-chlorobutadiene).
• the synthetic rubber is preferably present in the formulation at a level of from about 1% to 20% w/w, more preferably from 1% to 10% w/w, and most preferably about 5% w/w.
• the synthetic rubber is preferably dispersed or dissolved in a mixture of solvents.
• solvents may be used, including aromatic solvents such as xylene and toluene.
• aromatic solvents such as xylene and toluene.
• methyl isobutyl ketone Another example of a suitable solvent.
• Further components of the solvent system may be incorporated for reasons of economy, or to reduce the flash point of the formulation or to minimise noxious properties of the formulation.
• solvent components are mineral turpentine oil, turpentine substitute or white spirit, ie petroleum- derived solvents.
• a particularly preferred solvent is xylene.
• the xylene may be mixed with mineral turpentine oil or turpentine substitute, most preferably in approximately equal proportions.
• the formulation may also include further components which enhance the properties of the finished paper product or have other beneficial properties. Examples include preservatives or antioxidants (or optical whiteners) which prolong the life of the formulation. Such additives are generally present only at relatively low levels, typically less than 1%.
• plasticizers Particularly preferred plasticizers are dioctyl maleate and dioctyl phthalate. Such compounds are typically present at the level of a few %, most commonly between 1% and 10% w/w, typically around 5% w/w.
• the formulation may also include one or more components to increase the hydrophobicity of the paper surface and/or reduce aging. An example of such a material is paraffin wax, again typically at the level of a few %, most commonly between 1% and 10% w/w, typically around 5% w/w.
• additives which may be present in the formulation include polyvinyl acetate (typically 1 to 10% w/w), ethylene thiourea (typically 0.2 to 0.5%), sulfur (typically 0.1 to 2%), magnesium oxide (typically 1 to 4%), zinc oxide (typically 1 to 10%) and titanium dioxide (typically 1 to 10%). Numerous other additives, such as activators, catalysts, accelerators, cross-linking agents etc, may also be included in the formulation where appropriate.
• the formulation of the invention may be prepared by dissolving or dispersing all of the components directly in the solvent.
• the rubber may first be mixed or compounded with components such as the inorganic oxides, antioxidants etc and the mixture then dissolved or dispersed in the solvent.
• Components such as paraffin wax and polyvinyl acetate may be added to the solvent either before or after mixing of the solvent with the rubber mixture.
• the formulation according to the invention has the following characteristics:
• the process of the invention may be applied to any and all types of paper.
• the process may be applied during manufacture of the paper or paper product at any suitable stage.
• the process may be applied to a conventional paper at the end of the normal manufacturing process, or subsequently.
• the process may also be applied to completed paper products, eg assembled paper packaging units such as envelopes, boxes or cartons.
• completed paper products eg assembled paper packaging units such as envelopes, boxes or cartons.
• the external and/or internal surfaces of such packaging may be treated in accordance with the invention.
• the external and/or internal layers may be produced from papers treated in accordance with the invention.
• the process of the invention is of particular utility in relation to security papers for use in, for instance, banknotes.
• the lifetime of banknotes may be very short (eg no more than a few months) and the regular replacement of banknotes in circulation represents a very costly matter.
• By extending the lifetime of banknotes by treatment in accordance with the process of the invention very considerable savings may be made.
• Security papers subjected to the process of the invention may also incorporate other security features, eg watermarking, security threads etc.
• the water repellency of the paper in itself represents a security feature, being readily demonstrable and distinguishing banknotes made from paper in accordance with the invention from counterfeit notes.
• Waterproof or water-repellent security papers and items, eg banknotes, produced from them represent a further novel aspect of the present invention.
• the process of the invention may be applied to any kind of paper made of any kind of pulp, cotton comber or rag, before calendering, before or after polyvinyl alcohol / gelatine bath or final processing.
• the process may be applied before or after application of a watermark, eg by cylinder mould, four dinier or other process.
• the process may be applied before or after full or alternate embedding or window threading of any type of security thread, eg comet, continuous printed or unprinted, metallised or demetallised, positive text or negative text, magnetic or machine-readable threads etc. Coating by the process of the invention may also take place before or after incorporation of UN- detectable fibres.
• the process may also be applied after the paper is calendered and ready for use or printing.
• the process may be applied to all types of plain or printed papers, including currency, posters or packaging, before or after printing by any type of printing ink, including intaglio, magnetic, short-wave, UN, etc.
• Treated papers produced by the process of the invention may be used for any purpose, eg as currency (banknotes) of all denominations, secured documents, security papers, cheques, packaging papers. Papers for use in packaging may be converted into corrugated boxes, cartons, bags, or special purpose moisture-controlling packaging for soaps, detergents, medicines, processed and unprocessed food articles, fruit and vegetables, etc.
• the chemical formulation of the invention may be applied by various means, eg using a conventional varnishing machine, gravure machine, brush coating, dip coating or any other method of coating, or on-line during manufacture of the paper.
• the formulation may be applied either before or after printing, to paper sheets, paper web or any other paper article. Despite the reduced water absorptivity of the paper, it is nonetheless receptive to the printing process, eg by intaglio or dry offset printing.
• the process may be applied to any and all types of papers including banknote paper, security papers, craft papers, chromo-art, maplitho, yugoart, currency papers with or without security features.
• Plain or printed papers may be treated in the required quantity depending upon the requirements, in roll, sheet, container or any other desired form.
• polychloroprene 5 % w/w paraffin wax 5 % optical whitener 0.02 % dioctyl maleate 5 % xylene / mineral turpentine oil (50:50 mixture) to 100%
• the formulation is prepared by dissolving or dispersing the polychloroprene, paraffin wax, optical whitener (antioxidant) and dioctyl maleate (plasticizer) in the solvent mixture.
• polychloroprene 5 % w/w paraffin wax 5 % optical whitener 0.1 % dioctyl maleate 5 % ethylene thiourea 0.3 % magnesium oxide 4 % polyvinyl acetate 5 % titanium dioxide 2 % zinc oxide 5 % xylene / mineral turpentine oil (50:50 mixture) to 100%
• the formulation is prepared by mixing the polychloroprene, titanium dioxide, zinc oxide, ethylene thiourea and optical whitener, and then dissolving or dispersing the mixture in the solvent, either after or before addition to the solvent of the paraffin wax, polyvinyl acetate and dioctyl maleate.
• polychloroprene 5 % w/w paraffin wax 5 % optical whitener 0.1 % dioctyl maleate 5 % ethylene thiourea 0.3 % magnesium oxide 4 % titanium dioxide 2 % zinc oxide 5 % xylene / mineral turpentine oil (50:50 mixture) to 100%
• the formulation is prepared by mixing the rubber, sulfur and optical whitener, and then dissolving or dispersing the mixture in the solvent, either after or before addition to the solvent of the paraffin wax.
• a manufacturing line and process for a security paper incorporating a watermark and security thread contains the following stages:
• the formulation of the invention is applied at the point 10, using an on-line coating machine.
• the process may be applied at other stages.
• the treatment may be applied between stages 4 and 5, between stages 5 and 6, stages 8 and 9, stages 11 and 12, stages 12 and 13, stages 13 and 14, or subsequent to stage 14.
• the process of the invention comprising treatment of the paper with the chemical formulation of the invention, may also replace the PV A gelatin bath at stage 7.

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• 1998
  • 1998-09-26 GB GBGB9820877.0A patent/GB9820877D0/en not_active Ceased
• 1999
  • 1999-09-27 AU AU61058/99A patent/AU6105899A/en not_active Abandoned
  • 1999-09-27 DE DE69912824T patent/DE69912824T2/de not_active Expired - Fee Related
  • 1999-09-27 AT AT99947679T patent/ATE254213T1/de not_active IP Right Cessation
  • 1999-09-27 EP EP99947679A patent/EP1115948B1/fr not_active Expired - Lifetime
  • 1999-09-27 WO PCT/GB1999/003208 patent/WO2000019015A1/fr active IP Right Grant

Non-Patent Citations (1)

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