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
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/62—Rosin; Derivatives 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
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/10—Organic non-cellulose fibres
  • D21H13/12—Organic non-cellulose fibres from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H13/14—Polyalkenes, e.g. polystyrene polyethylene
• • 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
  • D21H17/20—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

Definitions

• This invention relates to heat-bonded paper webs made from a blend of natural cellulosic fibres and'synthetic thermoplastic fibres.
• Paper webs have traditionally been formed from cellulosic fibres derived from various materials of vegetable origin, for example woodpulp. Where it is desirable for the web to be susceptible to heat treatment, it has been proposed to incorporate a proportion of synthetic thermoplastic fibres in the web. Originally, chopped staple fibres were proposed for this purpose. However, such fibres are unfibrillated and incapable of hydrogen bonding, and thus they are inherently unsuited to the production of strong paper webs. With the exception of one or two speciality products therefore, the inclusion of chopped staple fibres in paper webs has not been widespread.
• synthetic woodpulp fibres have become available. These fibres are produced specially for use in papermaking, and have a gross morphology (i.e. length: diameter ratio) and diameter of the same order-of magnitude as cellulosic papermaking fibres derived from woodpulp. They also resemble cellulosic fibres in being fibrillated to a considerable extent, and they thus permit stronger webs to be obtained than is the case with chopped staple fibres. Examples of commercially-available synthetic wood- pulps are "SWP" supplied by Crown Zellerbach, "Pulpex” supplied by Solvay, and "Ferlosa” supplied by Montedison, all of which are polyethylenic. Fibres of other polyolefins may be used.
• thermoplastic fibres characterised in that the web also contains a resinous additive.
• the resinous additive may be a synthetic or a natural material.
• a suitable natural resin is rosin.
• Suitable synthetic resins include materials sold as wet- strength resins for paper, for example aminoplast resins such as melamine formaldehyde resin and urea formaldehyde resin. Melamine formaldehyde resin is particularly preferred (in this specification, the expression "resin"comprehends not only polymers having a large number of repeating units, but also so-called prepolymers or pre-condensates which have only a relatively small number of repeating units).
• polyamine resins such as epichlorohydrin-modified polyamine or polyamidepolyamine resins, polyethylene imine resins, and the resins sold as "Kymene” by Hercules Powder Company and "Nopcobond” by Diamond Shamrock Corporation.
• the amount of resjnous additive to be used is of the order of a few per cent, based on the total weight of the paper. Above a certain % addition, the improvement in properties after heat bonding levels off. For melamine formaldehyde resin, optimum results art achieved with additions of at least 2%.
• the relative proportions of cellulosic and synthetic thermoplastic fibres in the web may vary widely. Enhanced properties are obtained for example at 25%, 50% and 75% synthetic contents. Preferably however, the amount of synthetic fibres is from about 30% to about 50% based on the total fibre content.
• the type of cellulosic pulp used is not critical.. Bleached or unbleached softwood or hardwood kraft pulps may for example be used.
• a pre-heating step may be carried out to cure the resin before heat bonding at a higher temperature is carried out.
• the resinous additive may be incorporated in the web by methods normally used in the paper industry for the inclusion of additives. Beater addition is preferred.
• the furnish should be relatively free-beaten if it is desired to achieve an especially stretchable product.
• Heat bonding may be carried out by conventional techniques such as passage round a heated roller or passage through a heating tunnel.
• the present invention is applicable to the manufacture of products for a range of uses, but is particularly suited to the manufacture of base paper for bookbinding.
• Such paper needs to have good tear strength and tensile strength, and to be capable of stretching to a considerable degree. It is also desirable that it should be capable of easily accepting an emboss, for example a simulated leather emboss.
• emboss for example a simulated leather emboss.
• Such papers are conventionally made from latex containing wholly cellulosic webs. The present invention thus makes it possible to dispense with the need to incorporate latex into the paper-making furnish or with the need for a separate saturation step.
• melamine formaldehyde additive may be pre-heated to cure the resin before heat bonding treatment is carried out.
• the procedure involved taking some of the 2% MF handsheets prepared for Example 2 above and stoving them in an oven at 105°C for ten minutes before carrying out the three minute heat-treatment at 160°C.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Laminated Bodies (AREA)
• Reinforced Plastic Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10501116

Family Applications (1)

Country Status (1)

Cited By (4)

Citations (3)

• 1979
  • 1979-11-14 EP EP79302579A patent/EP0011488A1/de not_active Withdrawn

Patent Citations (3)

Similar Documents

Legal Events