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
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/23—Lignins
• • 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
  • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• • 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
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/30—Multi-ply
  • D21H27/40—Multi-ply at least one of the sheets being non-planar, e.g. crêped

Definitions

• the present invention relates to a process for the manufacturing of paper, particularly of paper useful as the intermediate layer ("medium”) of corrugated paper board, and to the thus resulting product.
• corrugated paper boards in their simplest form, consist of three layers, namely two outer layers, forming the faces of the paper board and called “liners”, and an intermediate, corrugated layer known in the related art as the "medium”.
• the main purpose of the present invention is that of providing a process for the manufacturing of paper, particularly "medium” paper for corrugated paper board, which permit less valuable raw material to be used, the properties of crush resistance and water repellency being maintained at the same level or, the type and concentration of raw materials being the same, permits the afore said properties to be improved.
• a more specific purpose of the present invention is that of providing a process of the afore said type which, in the case of the "semichemical" papers, and the physical and mechanical properties being the same, particularly the crush strength being the same, permits the contents of wood pulp to be reduced.
• Another likely more specific purpose of the present invention is that of providing a process of the afore said type which in the case of "fluting" paper, permits the crush strength to be increased by about 20%.
• a further purpose of the present invention is that of providing a process for the manufacturing of improved paper products, such as cardboards, wherein the "stiffness" it is a qualitatively important feature.
• the concentrated black liquor, before the application to the paper is supplemented with a small percentage of alcohols, preferably polivinyl alcohol.
• black liquors when they are to be used for the treatment of coloured papers, even of light colours, they can be previously treated by partial whitening and subsequent dyeing (for instance by means of H202) in a per se known manner.
• the qualifing and fully surprising feature, besides being novel, of the process of the invention is that by coating the paper, already dried to an optimum value of residual moisture content, with the black liquors, also previously concentrated, the resulting product is qualitatively and relevantly improved.
• FCT Flat Crush Test
• samples A Fours samples (samples A) of corrugated paperboard in which the medium layer had not been treated with black liquors, and four samples (samples B) of the same corrugated paperboard in which the medium paper had been treated with 10% concentrated black liquors were subjected to the FCT with following results: The percent increase of the crushing strength in this case was higher than 24%.
• the washing and squeezing of the wood particles or chips after the chemical cooking being repeated the most suitable number of times; like treatment is carried out on the pulp obtained from the beating operation as effected on the aforesaid chips, the resulting black liquors being recovered and combined.
• black liquors useful for the present invention there are contemplated not only those resulting from semichemical-and chemical cooking treatments of annual or multiannual plants, as by-products of the paper and/or cellulose manufacturing, but also the black liquors which are purposely produced from plants or wastes of annual and multiannual plants (such as straws of various nature, canes, etc.) saw mill wastes, vine-shoots, sawdusts and generally wood flours.
• the black liquors are than passed to a concentration plant, comprising two or more stages (depending on the sought concentration degree).
• the black liquors are produced in the plants for the manufacturing of chemical or semichemical paper starting from wood. They can be used again in the same paper mill or even used in paper mills producing "fluting" paper, namely from waste paper pulp. In the latter case, of course, the concentration of the black liquors is brought to at least 35 to 40% for transport saving.
• the resulting black liquors having greater or lesser viscosity and consistence, depending on the concentration degree, are coated onto the paper during its drying step, by means of coating rollers, or of any other suitable device depending or the type ofblack liquors.
• the coating of the paper can take place onto one or both surfances, or between one sheet and the other in the case of doubled paper, card board or paperboard, by using known coupling, coaling and impregnating machines.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)
• Laminated Bodies (AREA)
• Polarising Elements (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=11182899

Family Applications (1)

Country Status (11)

Cited By (1)

Family Cites Families (7)

• 1981
  • 1981-05-05 IT IT21512/81A patent/IT1138300B/it active
  • 1981-12-30 FR FR8124520A patent/FR2505378A1/fr not_active Withdrawn
• 1982
  • 1982-04-20 AT AT82200472T patent/ATE25411T1/de not_active IP Right Cessation
  • 1982-04-20 DE DE8282200472T patent/DE3275394D1/de not_active Expired
  • 1982-04-20 EP EP82200472A patent/EP0064309B1/de not_active Expired
  • 1982-05-04 ZA ZA823051A patent/ZA823051B/xx unknown
  • 1982-05-04 ES ES511912A patent/ES8304246A1/es not_active Expired
  • 1982-05-04 CA CA000402228A patent/CA1233303A/en not_active Expired
  • 1982-05-05 AU AU83402/82A patent/AU553303B2/en not_active Ceased
  • 1982-05-06 JP JP57075923A patent/JPS5823990A/ja active Granted
  • 1982-05-16 IL IL65788A patent/IL65788A/xx not_active IP Right Cessation

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