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
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/36—Inorganic fibres or flakes
  • D21H13/38—Inorganic fibres or flakes siliceous
  • D21H13/40—Inorganic fibres or flakes siliceous vitreous, e.g. mineral wool, glass fibres
• • 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
• • 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
  • 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
  • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• • 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
  • D21H17/47—Condensation polymers of aldehydes or ketones
  • D21H17/49—Condensation polymers of aldehydes or ketones with compounds containing hydrogen bound to nitrogen
  • D21H17/51—Triazines, e.g. melamine
• • 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
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
  • D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays

Definitions

• This invention relates to latex-bound paper, and provides non-asbestos alternatives to latex-bound asbestos papers.
• Latex-bound papers based on asbestos fibres are employed in the manufacture of gaskets and seals for use in motor vehicles, where they must be resistant to water, anti-freeze, oil a.nd petrol and withstand fairly high temperatures, e.g. 150°C. They are also used in the chemical industry in making seals resistant to chemical attack. They are commonly made in the form of flexible sheet of thickness 0.1-1.5mm on conventional paper-making machines such as the Fourdrinier. In the process an aqueous slurry of the ingredients which are to compose the product is progressively dewatered as a layer on a water-permeable conveyor (usually of wire mesh), the dewatered layer being subsequently compressed and dried.
• a water-permeable conveyor usually of wire mesh
• non-asbestos paper comprises vitreous fibres derived from wool-form material, organic web-forming fibres, unfired ball clay and water-insoluble non-fibrous particulate inorganic filler, the whole being bound toqether by a cured nitrile rubber; said paper being made by dewatering as a layer on a water-permeable conveyor an aqueous slurry whose solids content comprises by weight:- and compressing and drying the layer of dewatered slurry.
• the vitreous'wool-form fibre employed is preferably glass wool, mineral wool or ceramic fibre wool. If glass wool is used it is preferably employed in a form which has been treated with a silane coupling agent (e.g. gamma-aminopropyltriethoxysilane).
• silane coupling agent e.g. gamma-aminopropyltriethoxysilane
• the function of the organic web-forming fibres is primarily to enable the paper to be formed on conventional paper-making machinery, but additionally those fibres impart strength to the total matrix of the finished paper, just as the vitreous fibres derived from wool-form material (the primary reinforcement) do.
• the organic web-forming fibres are preferably cellulose fibres, but may alternatively be polyethylene or' polypropylene fibres of the kind commercially available under the name PULPEX.
• the function of the ball clay is to impart handlability to the paper sheet during manufacture.
• the wate-r-insoluble non-fibrous particulate inorganic filler may be of the kind conventionally used in paper manufacture, for example calcium carbonate, talc, calcium sulphate, kaolin, titanium dioxide, magnesium silicate, or barytes (barium sulphate).
• barytes which both densifies and improves the oil resistance of the paper, is particularly preferred.
• the nitrile rubber, which bonds all the fibrous and non-fibrous particles of the paper together is introduced during manufacture as a latex, together with a vulcanising (curing) agent of the usual kind.
• the paper may contain small amounts (e.g. 0.5-2.5% by weight) of fibres other than the vitreous fibres derived from wool-form material and the web-forming fibres.
• Such other fibres may for instance be low modulus carbon fibres or water-dispersible E-glass fibres. Such fibres improve green strength of the paper during manufacture; additionally the low modulus carbon fibres impart lubricity to the finished paper.
• Low modulus here means a Young's modulus in tension below 125GPa.
• a melamine-formaldehyde resin suitably at about 1% by weight, can be included in the slurry that is dewatered, in order to promote bonding between the various fibres and the nitrile rubber.
• a small quantity (0.002-0.01% by dry weight of total solids in the slurry) of a flocculating agent of the kind (e.g. a polyacrylamide polyelectrolyte) ordinarily used in paper making can be included in order to facilitate sheet formation and subsequent dewatering.
• a flocculating agent of the kind e.g. a polyacrylamide polyelectrolyte
• the stocks (slurries) prepared as in A. above from various formulations as set out in tablesl-3 following were made into flexible sheet material in an entirely conventional way on a Fourdrinier flat wire paper machine, such as is described in Chapters 10 and 11 of "Paper and Board Manufacture” by Julius Grant, James H. young, and Barry G. Watson (Publishers; Technical Division, The British Paper and Board Industry Federation, London, 1978).
• the slurry. is progressively dewatered as it travels on the water permeable conveyor of the machine, and the dewatered material is consolidated by pressing between rollers, and then dried to low moisture content (suitably 2% by weight).
• Paper was passed at room temperature between two smooth-faced steel rolls the gap between which was adjustable to control the density of the paper. Two such passes were made on the papers whose properties are reported in Table I.
• the hot calendering referred to in Table I was carried out as for cold calendering but with the difference that the steel rolls were heated to about a temperature of 145°C. Again, two such passes were made on the papers whose properties are reported in Table I.
• the purpose of hot calendering as opposed to cold calendering on latex-bound papers is to cause some flow of the latex, thus producing greater consolidation and a higher density.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Paper (AREA)
• Sealing Material Composition (AREA)

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Publications (1)

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Family Applications (1)

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Cited By (4)

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Citations (4)

• 1980
  • 1980-10-09 EP EP80303570A patent/EP0027706A1/fr not_active Withdrawn
  • 1980-10-15 BR BR8006648A patent/BR8006648A/pt unknown
  • 1980-10-17 JP JP14556180A patent/JPS5668198A/ja active Pending
  • 1980-10-17 ES ES496022A patent/ES8107350A1/es not_active Expired

Patent Citations (4)

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