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
  • D21H5/00—Special paper or cardboard not otherwise provided for
  • D21H5/12—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials
  • D21H5/20—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of organic non-cellulosic fibres too short for spinning, with or without cellulose fibres
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S206/00—Special receptacle or package
  • Y10S206/819—Material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
  • Y10T442/69—Autogenously bonded nonwoven fabric

Definitions

• This invention relates in general to paper making and in particular to a process of making paper and to the paper products so produced and includes correlated improvements designed to enhance the properties, characteristics, and uses of such products.
• the expression paper as employed in the following specification and in the appended claims is intended to include all waterlaid fibrous products produced from fibres having a paper-making length and includes products which are flexible or stiff, thin or thick, soft or hard.
• cellulose derivatives such as cellulose nitrate, cellulose acetate, and the like, are characterized by being inherently non-thermoplastlc, that is, when they are heated, they soften but do not become adhesive or tacky.
• Another specific object of the present invention is to provide a paper which will show an improved wet tearing strength whereby it is adapted for use as a paper towelling or for any use where the product is exposed to the weather, as in building construction and in camouflage.
• papers of improved properties, characteristics and uses are made by forming an aqueous suspension of normally non-adhesive fibres of paper-making length and synthetic resin fibres which are non-tacky at room temperature but which become tacky below the temperature at which paper-making fibres are damaged, depositing the mixture of fibres from said suspension in the form of a paper structure, drying and heating the structure to a temperature at which the resin fibres become tacky, and cooling the structure to effect fibre adhesion.
• the paper product is preferably subjected to pressure while the resin is in an adhesive condition.
• the expression paper structure" as used in the claims is intended to include sheets, layers, tubes and molded resin fibres adhesive.
• any fibres of pape geinaklng length which are not rendered adhesive'y tacky by the treatment that renders the
• the paper of the invention may be prepared from any suitable paper-making fibres of suitable paper-making length, namely, vegetable fibres such, for example. as wood, rag fibres, cotton, fiax, jute, straw or other fibres derived from plants of various kinds; mineral fibres such, for example, as glass fibres, rock wool, asbestos, and the like; animal fibres such, for example, as wool, leather fibres, silk fibres, in particular, si k waste, as well as fibres derived from gelatine, casein, glue, and the like.
• vegetable fibres such, for example. as wood, rag fibres, cotton, fiax, jute, straw or other fibres derived from plants of various kinds
• mineral fibres such, for example, as glass fibres, rock wool, asbestos, and the like
• animal fibres such, for example, as wool, leather fibres, silk fibres, in particular, si
• paper-making fibres as used herein, is intended to include all fibres adapted to be used in the making of paper, whether natural-occurring or artificial.
• vegetable fibres they may be prepared for paper-making by any suitable process such, for example, as the so-called sulphite process, sulphate process, soda process, kraft process or by suitable mechanical processes, and hydrated. bleached, washed, screened, beaten, aged and otherwise prepared for paper-making in a known manner.
• the mineral and animal fibres may be suitably purified and prepared for paper-making in a known manner.
• the potentially adhesive resin fibres are fibres which have an inherent tackiness upon heating to a temperature below that at which the non-adhesive paper-making fibres are damaged or rendered tacky, such as fibres formed from the copolymers of two or more resin-forming compounds such, for example, as co-polymers of vinyl halide and vinyl acetate, co-polymers of vinyl halide and acrylic acid, co-polymers of vinyl compound and styrol compound.
• the resin fibre For the thermoplastic fibre, it is preferred to employ the resin fibre because such fibres, as compared to the cellulose derivative fibres, are tougher and harder, become tacky at lower temperatures and cool to form tougher and more pliable products.
• the resin/ fibres used are preferably those which are inert to acids, alkalies and dry-cleaning fluids, and are not waterswelling. Use of such resins prevents distortion of the adhesive bond under changing atmospheric conditions or in the resence of salts, acids and alkalies, so that the wet and dry tensile strength of the adhesive bond will be substantially the same.
• the potential y adhesive resin fibres are preformed, extruded fibres and may be used in the unstretched or pre-stretched condition. However, since stretching tends to increase the cost and to render the resin brittle after heating, the use of unstretched resin fibres is preferred in the present invention.
• the potentially adhesive resin fibre used in the present process is a low-melting resin fibre formed from a vinyl copolymer containing less than 80% vinyl chloride and the remainder vinyl acetate and having a macro-molecular weight of below 10,000, and which was stretched during manufacture less than 70% and which has a heat distortion point below 70 C. Using such a resin fibre, porous, flexible and even flufly paper structures can be produced since little or no appreciable pressure is required during activation.
• the ratio of synthetic resin fibre to other fibre may also vary widely depending on the properties of the two types of fibres and may be regulated to suit the purpose for which the paper is destined, but in general a minor proportion, preferably from 3 per cent to 20 per cent of the synthetic resin fibre will be employed. Where a greater degree of strength or a closer bonding of the component fibres is desired, the percentage will be relatively high, whereas in papers of certain construction where it is desirable to have a comparatively small amount of bonding of the component fibres, the percentage will be relatively small.
• the non-adhesive paper fibres may be of any length suitable for paper-making and the length will vary with the type of machine used for mixing and sheeting the mixture of fibres.
• the resin fibres will have substantially the same length as the non-adhesive fibres, but in some cases where desired, the resin fibres are longer than the other fibres to aflord more points of adhesion per fibre length and to permit the manufacture of porous and flexible structures.
• the synthetic resin fibre and the paper-making fibre are mixed by a method suitable to the production of a particular type of paper, for example, by beating the fibres together in a suitable liquid or by adding the potentially adhesive fibres to the other fibres at any time prior to sheeting the fibres.
• the mixture of paper-making fibres and thermoplastic resin fibres may be formed into a web by a suitable process, for example, by the use of machines of various types, such as the Fourdrinier," Harper, single cylinder or “Yankee multi-vat machine, mould, presse pate,” or the like. It is to be understood that the invention is in no way limited to the use of any particular method or machine.
• the mixture of fibres may be beaten with water in a conventional manner in a paper pulp beater.
• the resin fibres are mixed with the other fibres and the mixture stirred, or beaten, only long enough to insure that the resin fibres are substantially uniformly distributed through the fibre mass.
• the fibers are usually bound together by the hydrated or beta cellulose which results from the beating of the fibers in water.
• This beating operation is expensive, time consuming and must be carefully controlled, otherwise the fibers may be insuificiently hydrated or they may be degraded so that they lose the greater part of their tensile strength.
• the beater being used merely as a means for mixing the paper fibres with the thermoplastic resin fibres.
• the tacky fibres serve to bind the paper fibres together, the bond being waterproof and nonswelling in water, thus being stronger and more permanent than the bonds produced by hydration of the paper fibres. Accordingly, the present invention provides for the production of a novel paper product in which the paper fibres are non-hydrated and un-degraded and bound together by waterproof permanent binders resulting from the heating of the thermoplastic resin fibres. In the preferred embodiment the resin fibres are bound to the paper fibres throughout the entire length or the resin fibres.
• the product will be porous, however, the activation of the resin fibres may be suflicient to cause these fibres to lose their structure and form an adhesive which extends throughout the product as a continuous filler, thus rendering the product non-pourous and waterand gas-impermeable.
• the inherent tackiness of the resin fibres is activated by heating the paper to an appropriate temperature, for example, by the use of dry hot air, contact with heated surfaces, or steam.
• the temperature of the heat-treatment will depend upon time, pressure and the properties of the resin fibre and must necessarily be below that at which the paper is damaged.
• the resin fibres become non-tacky and tough, and adhere to the other fibres, thus providing a paper product which possesses increased strength and greater tenacity between component fibres.
• the resin fibres in the paper may be activated during or after drying of the paper; if activated during drying, the resin fibres may be rendered adhesive by means of heated calender rolls cooperating with the last rolls of the drying rolls so that the paper is fed to the calender rolls in a pro-heated condition.
• the paper is preferably passed through a dryer where it is pre-heated before it is activated.
• the activation may then be carried out in a continuous manner as by means of a calender.
• the tackiness of the resin fibres may be modified by heating the resin fibres in the presence of a suitable plasticizer depending on the particular type of resin.
• the plasticizer may be incorporated in or carried by the resin fibres and/or by the non-adhesive fibres and may be incorporated in the fibres at any point prior to heating.
• the plasticizer is incorporated in the resin mass prior to its formation into fibres and filaments. The plasticlzer lowers the temperature at which the resin fibres are rendered tacky upon heating.
• the plasticizer may be allowed to remain or, if desired, it may be removed by suitable means, such as evaporation or extraction, thereby preventing the resin fibres from again being rendered tacky at the original activating temperature and capable of remaining nontacky at ironing temperatures.
• aqueous dispersion medium is recir- 6 culated and reused it is possible to incorporate plasticizers in the medium either as a solution or as a suspension.
• the paper product may be shaped into a pro-determined form by use of a suitable heated mould. If desired, the wet paper sheet may be shaped into a suitable form and then heated to dry the product and ultimately to activate the potentially adhesive fibres. In this way the pre-determined shape of the paper product will be permanently set by the binding of the fibres in the product.
• the present invention is adapted for making paper products of all kinds, such, for example, as tissue paper, writing paper, book paper. bank note paper, wrapping paper, news print, boards, including wall boards, building felts, and moulded paper articles of all kinds.
• paper product as used herein is intended to include all articles which are capable of being fabricated from paper-making fibres in accordance with the invention.
• the properties, characteristics, and uses of the paper produced may be varied over wide limits depending, interalia, on the nature of the papermaking fibres, the nature of the potentially adhesive resin fibres, the process of fabrication, the extent of activation of the resin fibres, and the relative proportion of the resin fibres to the paper-making fibres.
• With low percentages of resin fibres and/or with moderate activation of the resin fibres there may be produced articles having a substantial degree of flexibility, but also having an extreme toughness and resistance to folding, all of which are characteristics necessary in bank note paper.
• greater percentages of the resin fibres as from 10 to 50 per cent, there may be produced articles which are relatively stiff and resilient, which have a high resistance to bursting but which are still capable of being folded, bent, or shaped.
• relatively stiff paper products which may be machined with woodworking tools, thus adapting the products for use as panels, insulating materials, machine parts, and the like.
• the activation of the resin fibers may be varied in accordance with the properties desired in the finished products. For example, by merely heating the resin fibres to that temperature at which they are softened sufiiciently to. be deformed by the pressure applied, th non-adhesive paper fibres may be imbedded in the resin fibres although little or no actual adhesion occurs. If the resin fibres are heated to a somewhat higher temperature, that is sufficient to render them tacky, they will become bonded to the non-adhesive paper fibres at the points where the fibres cross each other. Under moderate pressure the resin fibres may thus be tacky or bonded to the other fibres at spaced points along the length of the resin fibres thus producing a three dimensional reticulated web in the fibre structure.
• the resin fibres may be tacky the paper product is subjected to a higher pressure the resin fibres may be bonded along their entire length with the other fibres thus producing a firmer and less porous structure than the structure previously described. Finally, at further increased temperatures and pressures, the resin fibres may be melted until they lose their fibre structure and the adhesive thus produced may be caused to spread through the paperproduct in the form of a more or less continuous film which will render the product more or less impermeable to gas and water.
• One embodiment of the present invention contemplates the use of the product as a thermoplastic laminating medium.
• the proportion of synthetic resin fibres be sufficient to cause the surfaces of the paper product to present tackiness on heating.
• the paper manufacturer may. therefore, manufacture the thermoplastic paper product for sale as a laminating medium prior to the activation of the synthetic resin fibres.
• Example I Ten per cent of synthetic resin fibres, insoluble in water, for example, a low melting resin fibre formed from a vinyl copolymer containing less than 80% vinyl chloride and the remainder vinyl acetate and having a macromolecular weight of below 10,000 and which was stretched during manufacture less than 70% and which has a heat distortion point below 70 C., may be mixed with unbeaten and substantially unhydrated papermaking fibres in the beater or in the head box of the paper machine, the beating being limited to that necessary to disperse the synthetic resin fibres through the paper fibres. The furnish or charge is then sheeted in a known manner on a Fourdrinier paper machine. The
• paper sheet is pre-heated on the drying cans and passed, while hot through calender rolls positioned at the end of the drying cans, the sheet being heated by such calender to a temperature of 125 C. and subjected to pressure of 300 pounds per square .inch which renders the resin fibres tacky.
• the product contains unhydrated paper fibres and is porous and flexible, it has a higher wet-tearing and bursting strength than the same sheet in which the resin fibres havenot been activated, or similar sheet not containing resin fibres and in which the paper fibres are hydrated.
• Example H Novel and improved paper board may be made by the following process: of fibres of a copolymer of 90% vinyl chloride and 10% vinyl acetate having a melting point of about 150 C. is added to a paper beater in which the furnish consists of waste newspaper fibres. The resulting charge is fed into a vat from which the fibres .are sucked upwards against a perforated plate by u e of vacuum to form alayer about one-half inch in thickness. The wet sheet is transferred to a belt and passed beneath the plates of a heat d fiat bed press wherein it is subjected to 300 lbs. of pressure per square inch without heat. The sheet is then removed from the press and passed through a drying chamber where the tempsrature of the sheet is gradually raised to 180 C.
• the sheet is passed while thuspre-heated through calender 8 rolls to compact the sheet while the synthetic resin fibres are in a tacky condition. Thereafter the sheet is allowed to cool.
• the resulting product will be a relatively stifi board adapted for use as wall board or for insulation, shoe construction, and the like.
• a process for making a paper product comprising forming an aqueous suspension of cellulosic paper-making fibers of paper-making length and water-insoluble preformed, extruded thermoplastic resin fibers oi paper-making length while maintaining said resin fibers in fibrous form, said resin fibers being formed from a copolymer of vinyl chloride and vinyl acetate and being normally non-tacky, flexible, and tough, and being rendered tacky at a temperature below that at which the papermaking fibers are damaged; removing water from said suspension to deposit said paper-making and said resin fibers in the form of a paper product; and heating said product to efiect a tough. pliable, water-resistant bonding of fibers in said product, without destruction of the fibrous structure of said resin fibers.
• a process for making a paper product comprising forming an aqueous suspension of a mixture of cellulosic fibers of papermaking length and water-insoluble pre-formed. extruded thermoplastic resin fibers of papermaking length by heating said fibers with water for a period sufiicient to mix the fibers uniformly but insumcient to hydrate said cellulosic fibers substantially and insumcient to destroy the fibrous nature of said resin fibers, said resin fibers being formed from a copolymer of vinyl chloride and vinyl acetate and being normally non-tacky, flexible, and tough, and being rendered tacky at a temperature below that at which the papermaking fibers are damaged; removing water from said suspension to deposit said fibers in the form of a paper product comprising said paper-making fibers and said resin fibers; and heating said product to eflect a tough, pliable, water-resistant bonding of fibers in said product, without destruction of the fibrous structure of said resin fibers.
• a process for making a molded paper product comprising forming an aqueous suspension of a mixture of paper-making fibers of paper-making length and water-insoluble preformed, extruded thermoplastic resin fibers of paper-making length while maintaining said resin fibers in fibrous form, said resin fibers being formed from a copolymer of vinyl chloride and vinyl acetate and being normally non-tacky, flexible, and tough, and being rendered tacky at a temperature below that at which the papermaking fibers are damaged; removing a mixture of said paper-making and said resin fibers from said suspension in the form of a shaped structure by the use of a mold; and heating said structure to efl'ect a tough, pliable. water-resistant bonding of fibers in said product, without destruction of the fibrous structure of said resin fibers.
• a. paper product comprising water-laid paper-making fibers and water-insoluble pre-iormed, extruded, thermoplastic resin fibers formed from a copolymer of vinyl chloride and vinyl acetate, said resin fibers being normally non-tacky, flexible, and tough, and being rendered tacky at a temperature below that at which the paper-making fibers are damaged, fibers in said product being bonded to each other due to the thermal tackiness alter heating of said resin fibers.
• a paper product comprising a water-laid mixture or cellulosic paper-making fibers and water-insoluble pretormed, extruded, thermoplastic resin fibers formed from a copolymer of vinyl chloride and vinyl acetate, said resin fibers being normally non-tacky, flexible, and tough. and being rendered tacky at a temperature below that at which the paper-making fibers are damaged, fibers in said product being bonded to each other due to the thermal tackiness after heatin of said resin fibers.
• a paper product comprising a water-laid mixture of substantially unhydrated celluloslc paper-making fibers and water-insoluble pre-iormed, extruded, thermoplastic resin fibers formed from a ccpolymer or vinyl chloride and vinyl acetate, said resin fibers being normally non-tacky, flexible, and tough, and being rendered tacky at a temperature below that at which the paper-making fibers are damaged, fibers in said product being bonded to each other substantially solely due to the thermal tackiness after heating 0! said resin fibers.
• thermoplastic resin fibers oi paper-making length while maintaining said resin fibers in fibrous form to form a paper product comprising said aper-making fibers and said resin fibers and adapted to be heated to render said resin fibers tacky and to efiect bonding of fibers in said product by the thermoplastic material of said resin fibers; the said resin fibers being tormed oi. a copolymer oi. vinyl chloride and vinyl acetate and being normally non-tacky,
• thermoplastic resin fibers formed from a ccpolymer oi vinyl chloride and vinyl acetate, said resin fibers being normally non-tacky, flexible, and tough, and capable of being rendered tacky at a temperature below that at which the papermaking fibers are damaged to provide a product in which fibers in said product are bonded by the thermoplastic material 0! said resin fibers.

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• Paper (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23764881

Family Applications (1)

Country Status (4)

Cited By (36)

Families Citing this family (6)

Citations (16)

• 0
  • BE BE475208D patent/BE475208A/xx unknown
• 1942
  • 1942-05-25 US US444438A patent/US2526125A/en not_active Expired - Lifetime
• 1947
  • 1947-08-06 FR FR951617D patent/FR951617A/fr not_active Expired
• 1950
  • 1950-07-19 DE DEA3013A patent/DE835393C/de not_active Expired

Patent Citations (18)

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