Classifications

• • 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
• • 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
  • D21C3/00—Pulping cellulose-containing materials
  • D21C3/006—Pulping cellulose-containing materials with compounds not otherwise provided for

Definitions

• the invention relates to a process for the production of cellulose fiber material from vegetable substrate containing calcium pectinate.
• Vegetable substrates have been used for a long time for the production of cellulose fiber materials.
• a material is, for example, cellulose, which is generally obtained from wood and is an important commercial product that is used for paper production.
• the class of cellulose fibers also includes so-called sclerenchyma or bast fibers, which form the supporting tissue of plants such as stalks or stems. In nature, these fibers are always in combination with substances such as lignins and pectins. These accompanying substances must be removed if the cellulose fiber material is to be obtained in a form suitable for further processing.
• the plant substrate used is digested, de-wooded, de-pectinized and, if necessary, also bleached.
• the raw material is the most important and currently used on a technical scale for cellulose production digested with sodium hydroxide solution.
• Different additional chemicals can be present here.
• sodium digestion NaOH, Na 2 CO 3
• the sulfide process CaO, MgO, NaOH, NH 4 OH / SO 2
• the sulfate process NaOH, Na 2 S, Na 2 CO 3
• the chemicals mentioned each form the so-called "cooking acids”.
• the digestion primarily results in the delignification (de-lignification) of the plant substrate, the lignins contained in the substrate being converted into a soluble form.
• the known methods have the disadvantage that, in addition to the desired delignification, the cellulose fibers are also attacked to a considerable extent. This means that the strength of the pulp obtained at the end is reduced. The cellulose yield also drops. Therefore, not only is the lignin dissolved, but also some of the cellulose fibers of interest are undesirably destroyed. It is believed that the degree of polymerization is reduced or the fiber length is shortened. Some of the cellulose even goes into solution.
• the known digestion processes also cause problems due to the waste products to be disposed of, the waste water question in particular being an important aspect.
• the pectins and calcium pectinates present in the plant substrates must also be removed, the calcium pectinates in particular generally causing difficulties.
• the invention is therefore based on the object of providing a new process for the production of cellulose fiber material from plant substrate containing calcium pectinate, in which the cellulose fibers are not damaged, compared to the known processes the environment less burdened and the duration of the procedure can be shortened.
• This object is achieved by a process in which the vegetable substrate is digested and optionally bleached, the process being characterized in that trisodium phosphate is used for the digesting.
• Trisodium phosphate is usually used for softening water such as boiler feed water, for phosphating, as a component of soap powders and toilet soaps, in dishwashing detergents or as a buffer.
• the vegetable substrate used in the claimed process is preferably selected from plants of the Linaceae, Urticaeae or Moraceae families and this group includes in particular oil linen, fiber linen (flax), nettles such as nettles, ramie, hemp or hops. Flax is particularly preferred.
• the vegetable substrate is digested in an aqueous solution which preferably contains 2.5 to 20 g of trisodium phosphate per liter of water and preferably 3 to 10 g, in particular 3.5 to 8.5 g, but more preferably 5 to Contains 7 g of trisodium phosphate per liter of water.
• this digestion solution preferably also contains a dispersing agent and / or a bleaching agent. If the bleaching agent is present in the digestion solution at the same time, a shortening of the process is even advantageously possible since subsequent bleaching of the cellulose fiber material obtained, if desired, can be omitted. The cost savings for this can be considerable.
• any agent suitable for this purpose in such digestion solutions can be used as the dispersing agent, but preferably water glass or a surfactant or a surfactant mixture is used, suitable surfactants and surfactant mixtures preferably containing anionic surfactant and possibly small additions of nonionic components.
• a suitable surfactant product is, for example, Cottoclarin® from Henkel.
• the bleaching agent is preferably hydrogen peroxide, which can be used, for example, in the form of a 35% aqueous solution.
• hydrogen peroxide preferably hydrogen peroxide
• other known bleaching agents suitable for cellulose fiber bleaching can also be used.
• the amount of dispersant present in the digestion solution is preferably in the range from 0.5 to 10 g / 1, in particular 1 to 5 g / 1 and preferably 3 g / 1.
• the bleaching agent is present in the digestion solution in an amount of preferably 0.1 to 15 g / 1, in particular 1 to 10 g / 1 and preferably 5 to 8 g / 1, in the case of hydrogen peroxide in the form a 35% aqueous solution according to a preferred embodiment, 8 ml of this hydrogen peroxide solution per liter of digestion solution can also be used.
• the vegetable substrate is simultaneously with the digestion by the trisodium phosphate with borax treated or pretreated with an aqueous borax solution before digestion by the trisodium phosphate.
• the amount of borax present in this simultaneous treatment or in this pretreatment solution is preferably in the range from 0.5 to 10 g / 1, in particular 1 to 5 g / 1 and preferably 3 g / 1.
• the pretreatment of the vegetable substrate with this solution is preferably carried out at a temperature of 30 to 60 ° C., preferably 40 to 50 ° C. and in particular at 45 ° C. This pretreatment advantageously enables a higher degree of bleaching of the cellulose fiber material obtained, the bleaching preferably taking place simultaneously with the digestion.
• the vegetable substrate can also be disrupted in two successive identical sub-stages. Between these stages, the part of the undesired accompanying cellulose fiber substances dissolved up to that point can be removed. This two-step procedure facilitates the extensive or complete removal of these substances.
• the cooking solution used for this purpose is drained off and the residue is rinsed with water, which preferably has a temperature which corresponds to the drained solution or can be somewhat lower.
• the container with the washed residue is then refilled with water, it being possible for the water to be adjusted to a pH of about 8, for example with trisodium phosphate.
• the water used for rinsing can also be treated accordingly.
• the cellulose fiber material obtained is then treated with an enzyme or enzyme mixture in the aqueous solution adjusted to a pH of 8.
• an enzyme or enzyme mixture in the aqueous solution adjusted to a pH of 8.
• pectases and lignases can also be present in an enzyme mixture.
• a suitable enzyme product for starch degradation is, for example, Thermamyl from Novo Nordisk.
• the enzyme or enzyme mixture or enzyme product can be used in an amount of 1 to 10 ml per liter of water, in particular 2 to 8 and preferably 3 to 5 ml per liter of water.
• After the enzyme treatment is rinsed again and the cellulose fiber material obtained is dried.
• the pH of the water can be changed as needed depending on the enzyme used. With Thermamyl ® as enzyme, a pH of 8 is preferred.
• Another advantage of the method according to the invention is that the pectins and calcium pectinates removed after or during the digestion can be recovered in a form in which the gelling ability has largely been retained.
• the mixture was made up with water which had a temperature of 70 ° C. and a pH of 8.0 (trisodium phosphate) and contained 3 ml / l of the enzyme Thermomyl.
• the substrate to be treated was left in this bath for 30 minutes. It was then rinsed twice with water at a temperature of 45 ° C. and dried.
• the cellulose fiber material obtained had the following properties:
• the properties of the cellulose fiber material obtained corresponded to those of the product from Example 1.

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Citations (4)

• 1995
  • 1995-11-17 WO PCT/EP1995/004521 patent/WO1997019221A1/de not_active Ceased
  • 1995-11-17 CZ CZ981468A patent/CZ146898A3/cs unknown
  • 1995-11-17 AU AU41730/96A patent/AU4173096A/en not_active Abandoned
  • 1995-11-17 DE DE59507926T patent/DE59507926D1/de not_active Expired - Fee Related
  • 1995-11-17 EP EP95940192A patent/EP0861347B1/de not_active Expired - Lifetime

Patent Citations (4)

Non-Patent Citations (1)

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