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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
  • D21H23/06—Controlling the addition
  • D21H23/14—Controlling the addition by selecting point of addition or time of contact between components
  • D21H23/18—Addition at a location where shear forces are avoided before sheet-forming, e.g. after pulp beating or refining
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
  • D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
• • 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
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
• • 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
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/14—Secondary fibres

Definitions

• the present invention relates to the manufacture of paper or cardboard from recycled fibers.
• the paper industry is increasingly using raw materials made from recycled fibers. With each recycling, the quality of the raw materials deteriorates and it is generally necessary to find a satisfactory level for the mechanical characteristics of the paper or cardboard produced, to subject the pulp to a refining.
• the invention provides a method of manufacturing paper or cardboard using a paper machine, from at least one jet of an aqueous suspension of recycled fibers on the fabric of the paper machine, which allows increase the output of the paper machine, while allowing good sheet formation.
• the paper composition is made to act, essentially based on recycled fibers, before the at the end of the aqueous suspension of fibers on the canvas, an enzymatic preparation containing cellulases and / or hemicellulases and / or other enzymes having an action on all or part of the constituents of recycled cellulosic fibers which leads to an improvement in drainage , at a temperature between 15 and 80 ° C, at a pH between 3 and 8, for a period greater than 5 minutes and preferably between 10 minutes and 1 hour.
• This process therefore aims not to improve the drainage of the treated dough, but to improve its ability to refine.
• the action of the enzymes is different. They act here on a pulp of recycled fibers which has poor machinability, due to poor drainability.
• the action of the enzymes will result in an improvement in the drainability which will allow either a greater dilution of the paper composition in the headbox, or an increase in the speed of the machine and ultimately a gain in productivity, or both.
• the action of enzymes also results in an improvement in the mechanical characteristics of the sheet of paper, made from recycled fibers. It also results in that it allows the use as raw materials of a large percentage of fibers of very low categories, such as the category designated by wholesale store.
• one aspect of the invention aims to provide a method for improving the machinability of a paper composition during the manufacture of a paper strip from a suspension of recycled fibers.
• Another aspect of the invention aims to provide a process for manufacturing a paper from a composition of recycled fibers containing fibers of very low category in non-negligible percentage, which are normally incorporated at much lower rates in conventional papermaking processes, since they greatly penalize not only the drainability of the resulting fibrous suspensions, but also the mechanical properties of the papers produced from said fibrous suspensions.
• enzymatic preparations containing cellulases and / or hemicellulases and others such as esterases, mananases, etc. which are used according to the invention, preferably those which have a C1 activity, a C activity are chosen.
• x and xylanasic activity are chosen.
• the activity C De is the action of cellobiohydrolase which can be assayed on very organized pure cellulose. This activity is manifested by the production of cellobiose and the international system has retained the AVICEL substrate as the reference substrate.
• the activity C x is assayed on modified cellulose, carboxymethylcellulose for example and it is quantified by a fall in the viscosity of the carboxymethylcellulose or an increase in the reducing activities.
• the xylanasic activity allows hydrolysis of the binding xylans.
• the enzyme preparation is used at an enzyme concentration which varies according to the C1, C x or xylanasic activities of the enzymes contained in the preparation.
• the enzymatic preparation is preferably used at a concentration of 0.01% to 2% of the weight of the dry dough, these percentages corresponding to a preparation having a C1 activity of 0.168 USI per milligram of powder, an activity C x of 3.9 USI per milligram of powder and a xylanasic activity of 31 USI per milligram of powder.
• the concentrations of the enzyme preparations can be adapted according to the type of preparation used. However, it generally remains with enzyme preparations whose activities have been described above, below a concentration equal to approximately 0.01% of the weight of the dry dough, no significant effect is observed, except to extend the reaction time until durations unsuitable for industrial production rates. at around 2% of the weight of the dry pulp, the cost of the operation tends to become prohibitive, and the mechanical characteristics of the paper produced tend to drop.
• the reaction medium can be more or less suitable for the action of enzymes. Temperature and pH conditions are more particularly suitable for avoiding any risk of denaturation of the enzymes by the medium.
• the pH is thus between 3 and 8, and the temperature between 15 ° C and 80 ° C. Above 80 ° C, the medium tends to denature the enzyme, and below 15 ° C, the action of the enzymes manifests itself particularly slowly.
• the process according to the invention advantageously proposes to adapt the enzymatic preparation to industrial operating conditions, generally used in stationery, that is to say without other modifications to the manufacturing process.
• Examples 1 to 15 demonstrate the action of enzymatic preparations on the drainability of paper compositions based on recycled fibers.
• Examples 16 to 20 show the advantages and in particular the productivity gains provided by the invention on an industrial machine.
• An aqueous suspension of paper pulp based on recycled fibers is prepared as follows:
• aqueous suspension It is made into an aqueous suspension at 3% by weight, adding water to a total weight of 33.333 kg.
• the pH of the fibrous suspension is adjusted to the desired value, by adding either sulfuric acid (H2SO4, 1N) to obtain acidic pH, or sodium hydroxide (NaOH, 1N) to obtain basic pH.
• An advantageous way of proceeding is to control the pH using a pH meter when adding either the acid or the base, while homogenizing the fibrous suspension.
• the fibrous suspension is brought to the desired temperature rée. Once this temperature has been reached, 1.6 ml of an enzymatic solution based on cellulases and hemicellulases, marketed under the name Multifect L 250, by the company FINNISH SUGAR CO are introduced.
• the enzymes are allowed to react for a variable time according to the examples and the drainability of the paper suspensions is measured using the BRITT-JAR apparatus according to the protocol described below. Drainability is thus measured before the introduction of the enzyme
• a suspension of paper fibers is prepared at a concentration of 10 g / l and 650 ml of this suspension are taken and poured into the BRITT-JAR device which comprises a cylindrical body with a diameter of 10.2 centimeters at the base of which is a filter cloth of the same nature and characteristics as the cloth of the paper machine.
• This device is marketed for example by the company NOVIPRO.
• the volume of water which has passed through the fabric after 15 seconds under a vacuum of 0.2 bars, without stirring the aqueous suspension, is called draining (or drainability).
• the measure of drainability before the introduction of enzymes is 320.
• the examples show that the treatment of the suspension with enzymes provides an increase in the drainability of the fibrous suspension, which leads to a higher speed of drainage and therefore a better machinability.
• the starting fiber composition is made up of 95% by weight of boxes of salvage cardboard and 5% by weight of warehouse wholesale. Using a pulper, an aqueous suspension at 30 g / l is made of it continuously. This suspension then passes through the various standard purifiers and storage tanks. In the last of these vats, while the fiber suspension is at a temperature of 45 ° C and a pH of 6, an enzyme preparation based on cellulases and hemicellulases is introduced therein, at the rate of 1.2 liters. per dry ton of paper produced, of a solution sold under the name Multifect L 250 TM by the company FINNISH SUGAR CO Ltd. It is left to react during the time of passage of the suspension in the vat which cor responds to approximately 30 minutes.
• the suspension treated with enzymes is then sent to the headbox, where it is brought to a concentration of 7.4 g / l.
• composition is poured onto the canvas of the paper machine which moves at a speed of 250 m / min.
• the burst index is measured in accordance with standard NFQ 03053. This index represents the quotient of the maximum pressure distributed uniformly, and supported by a test piece of paper, perpendicular to its surface, by the grammage of the paper. In this example we find a burst index of 1.79.
• Example 15 The procedure is as in Example 15, except that there is no enzyme treatment.
• the concentration in the headbox is 9.5 g / l so as to obtain the best compromise between correct drainability and maximum production.
• the production obtained is 3.89 tonnes / hour.
• the burst index of manufactured paper is 1.64.
• This comparative example highlights the advantages provided by the invention: greater dilution in the headbox and an increase in the speed of the machine, this gain results in a gain in productivity. There is also a gain in paper characteristics.
• Example 16 The procedure is as in Example 16, except that the concentration in the headbox is modified by keeping the same concentration as in Comparative Example 16, and by increasing the speed of the machine to bring it to 255 m / min. Production reaches 4.22 tonnes / hour.
• the measured burst index is 1.65.
• Example 16 the procedure is as in Example 16, but the fibrous composition which is formed here is 80% of recycled cardboard boxes and 20% of warehouse bulk.
• the headbox concentration is 8.5 g / l and the machine speed is 241.8 m / min.
• the measured burst index is 1.65.
• the action of the enzymes by improving the drainability of the fibrous suspension makes it possible to increase the dilution in the headbox and thus to improve the formation of the sheet.
• a 190 g / m2 cover paper is made from a fibrous composition of 80% box clippings and 20% good cardboard.
• Example 15 The procedure is as in Example 15 using an enzyme dosage of 0.9 l / tonne of dry product paper.
• the headbox concentration is 8.6 g / l and the machine speed is 163.3 m / min. Paper production is 3.92 tonnes / hour.
• the measured burst index is 2.33.
• Example 19 The procedure is as in Example 19, except that the paper composition is not treated with enzymes.
• the concentration in the headbox for the best compromise between drainability and production is 10.5 g / l and the speed of the machine is 153.6 m / min. Paper production is 3.69 tonnes / hour and the burst index is 2.14.
• This comparative example highlights the advantages obtained by the invention over the productivity and characteristics of paper with another starting papermaking composition.
• the treatment with an enzymatic preparation based on cellulase and / or hemicellulase makes it possible to dilute more strongly in the headbox, which provides better sheet setting, while increasing the speed of the machine.
• Example 16 We operate as in Example 16, but taking as com starting position 80% box clippings and 20% Krafts bags.
• the dosage of enzymes is 0.65 l / tonne of paper produced.
• the headbox concentration is 8.5 g / l and the machine speed 152.3 m / min.
• Paper production is 3.78 tonnes / hour.
• the measured burst index is 2.84.
• Example 20 The procedure is as in Example 20, except that the paper composition is not treated with enzymes.
• the concentration in the headbox for the best compromise between drainability and production is 10.2 g / l and the machine speed is 151.4 m / min. Paper production is 3.61 tonnes / hour and the burst index is 2.75.

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• Microbiology (AREA)
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Citations (3)

• 1988
  • 1988-03-22 FR FR8803687A patent/FR2629108A1/fr active Granted
• 1989
  • 1989-03-14 NO NO89891085A patent/NO891085L/no unknown
  • 1989-03-20 JP JP1066462A patent/JPH026681A/ja active Pending
  • 1989-03-20 EP EP89400770A patent/EP0334739A1/fr not_active Withdrawn
  • 1989-03-20 CA CA000594234A patent/CA1333317C/fr not_active Expired - Lifetime
  • 1989-03-21 FI FI891348A patent/FI891348A/fi not_active Application Discontinuation
• 1991
  • 1991-02-11 US US07/653,975 patent/US5110412A/en not_active Expired - Lifetime

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