WO2019170667A1 - Pâte à usage chimique - Google Patents

Pâte à usage chimique Download PDF

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Publication number
WO2019170667A1
WO2019170667A1 PCT/EP2019/055436 EP2019055436W WO2019170667A1 WO 2019170667 A1 WO2019170667 A1 WO 2019170667A1 EP 2019055436 W EP2019055436 W EP 2019055436W WO 2019170667 A1 WO2019170667 A1 WO 2019170667A1
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Prior art keywords
pulp
molecular weight
pulps
chemical
log
Prior art date
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PCT/EP2019/055436
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German (de)
English (en)
Inventor
Gabriele Schild
Verena Silbermann
Original Assignee
Lenzing Aktiengesellschaft
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Publication of WO2019170667A1 publication Critical patent/WO2019170667A1/fr

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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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
    • D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D01F2/06—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from viscose
    • 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
    • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
    • D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites
    • D21C3/10—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites magnesium bisulfite
    • 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
    • D21H13/02—Synthetic cellulose fibres

Definitions

  • the present invention relates to a chemical pulp, its use for the production of cellulose fibers, in particular lyocell fibers, and lyocell fibers which are produced by the
  • the predominant processes for producing chemical pulps are the Kraft process and the sulfite process.
  • a significantly lower viscosity is required than for papermaking and a higher purity, that is, the cellulose chains must be further split and low molecular weight carbohydrates, extractives and transition metals
  • Pre-hydrolyzate for further processing. It not only contains dissolved low molecular weight carbohydrates but also small amounts of dissolved lignin. Upon relaxation of the container and emptying of the pre-hydrolyzate these Ligninbruch Ser fall out, condense and lead to significant sticking to pumps, valves and piping. This problem has so far been bypassed industrially so that chemical pulps with the
  • Prehydrolysis Force Procedures are only produced on a campaign basis and mainly Be cooked paper pulps that do not require prehydrolysis. With the alkaline cooking liquor for the production of paper pulp, therefore, in between all
  • the pulp is treated with pure caustic soda or white liquor from the recovery of the power process to remove the low molecular weight fraction of carbohydrates.
  • the CCE liquor with the dissolved carbohydrates is pressed off. With ultra or nanofiltration these carbohydrates can then be removed from the
  • a chemical pulp to be used should have a low viscosity of 250 to 430 ml / g. In addition, it should have a very low proportion of low molecular weight carbohydrates. The proportion of low molecular weight
  • Carbohydrates are determined in practice over industry standard values such as R18, S18, alpha content or the like.
  • degree of polymerisation of the carbohydrates can be represented by SEC (size exclusion chromatography) as molecular weight distribution.
  • Chemical pulps vary according to the manufacturing process
  • pulps produced by a kraft process are referred to as "kraft pulps” and pulps produced by sulfite processes are referred to as “sulfite pulps”.
  • Paper pulps that is, high yield pulps, have a bimodal molecular weight distribution when made from hardwood, or at least one additional low molecular weight shoulder when made from softwood (Sixta 2006, 11.2 Paper-Grade Pulp p. 1018). ,
  • bimodal here and below denotes a molecular weight distribution which has more than one maximum, in particular two maxima.
  • lignin and extractives may have low molecular weight carbohydrates.
  • their content of residual lignin and extractives preferably ⁇ 0.1%) must be very low so that they can be processed without difficulty, such as foaming in the process or deposits,
  • the present invention has set itself the task of a new chemical pulp for
  • FIG. 1 shows a comparison of the typical molecular weight distribution of a commercially available prehydrolysis kraft pulp and of a commercially available sulphite pulp.
  • Figure 2 shows the molecular weight distribution of an embodiment of the pulp according to the invention, compared with the molecular weight distribution of two kraft pulps.
  • FIG. 3 shows the molar mass distribution of two further embodiments of the invention
  • Pulp according to the invention compared with the molecular weight distribution of a commercially available sulfite pulp.
  • FIG. 4 shows the molecular weight distribution of a further embodiment of the invention
  • Pulp according to the invention compared with the molecular weight distribution of a commercially available sulfite pulp
  • Chemical pulp may be produced by a conventional acid sulfite process followed by TCF or ECF bleaching.
  • the increased yield of low molecular weight carbohydrates in the pulp significantly increases the yield. This leads to an overall higher use of the raw material wood and thus to an improved
  • a bimodal molecular weight pulp pulp is to be understood as meaning a single pulp which is produced by boiling from a single starting material and not by mixing a plurality of pulps having a different molecular weight distribution.
  • low molecular weight cellulose is formed, while it is formed in the bimodal pulp according to the invention from hemicelluloses and a low proportion of low molecular weight cellulose.
  • a chemical pulp already differs by its overall lower average molecular weight.
  • DP average degree of polymerization
  • the DP of chemical pulps for the lyocell process is approximately between 600 and 2000 (log M w 5.0 to 5.5).
  • the data from log M are based on the (if appropriate average) molar mass in g / mol.
  • the pulp according to the invention is produced by a sulfite pulping process.
  • Pulps produced by a sulfite pulping process differ in the same parameters as DP, viscosity and the like. from one to a force method
  • inventive chemical pulp may be prepared by a magnesium bisulfite process.
  • Molar mass distribution in the range of 4.2 to 6.0 log M, preferably 4.3 to 5.7, more preferably 4.5 to 5.5 characterized.
  • inventive chemical pulp is characterized by a second
  • the low molecular weight fraction of hardwood pulp has a maximum of about log M 4.2 for sulfite and 4.7 for kraft pulps. There is about the minimum for the inventive chemical pulps.
  • the inventive chemical pulp is further characterized by a weight average molecular weight of log M w 5, 0-5, 5 g / mol, preferably 5, 2-5, 5 g / mol. This is below the weight average molecular weight of paper pulps.
  • the proportion of cellulose is below 95% by weight. Accordingly, it means that the content of hemicelluloses is 5% by weight or more.
  • the inventive chemical pulp is characterized by a proportion (% by weight) of polymer chains with a log M w of 5.5 (corresponds to a DP of 2000) or more of 25% or less, preferably ⁇ 22%, more preferably ⁇ 19%. This proportion is significantly lower than that of
  • the pulp of the invention may be made of hardwood, softwood or a mixture of both.
  • the chips used to make the pulp may be made from logs, sawdust, waste wood or any mixture thereof.
  • the bark content should not exceed 2%, preferably 1%.
  • the pulp according to the invention is preferably characterized in that it has a
  • the pulp according to the invention may preferably be bleached totally chlorine-free (TCF).
  • the pulp according to the invention may have an acetone extractant content of> 0.1%.
  • extractant groups the following groups with typical amounts were found in embodiments of the pulp according to the invention:
  • the pulp according to the invention may have a copper number of> 2.0%.
  • the pulp according to the invention can be produced by a kraft or sulfite pulping process, in particular by the magnesium bisulfite process.
  • the glucomannan which accounts for the majority of hemicelluloses in softwood, can be stabilized by a lower temperature regime and thus preserved in the pulp (Rydholm 1985, p. 512).
  • the setting of the glucomannan which accounts for the majority of hemicelluloses in softwood, can be stabilized by a lower temperature regime and thus preserved in the pulp (Rydholm 1985, p. 512).
  • Process parameters in the delignification of the process ie during the cooking and Oxygen bleaching or alkaline extraction take place. This can be z. B. with the help of a change of the SCk offer in the cooking acid or with the lowering of the H-factor happen.
  • the H-factor is a factor known from the literature (Sixta 2006), which describes the intensity of the digestion process on the basis of the variables temperature profile and time.
  • the present invention also relates to the use of an inventive
  • Chemical pulp for the production of Cellulosischen Formkörpem in particular fibers, in particular for the production of Lyocellfasem or viscose fibers, preferably for
  • the present invention also relates to a cellulosic molded body, in particular a lyocell fiber, obtainable by spinning an organic solution of a chemical pulp according to the invention, in particular a solution of the pulp in an aqueous tertiary amine oxide.
  • a molded body according to the invention in particular a lyocell fiber according to the invention, is characterized in that the proportion of cellulose is less than 95% by weight. That is, conversely, the content of hemicelluloses is 5% by weight or more.
  • the molecular weight distribution is determined by size exclusion chromatography (SEC) in DMAc-LiCl solution.
  • SEC size exclusion chromatography
  • MALLS multi-angle laser light scattering
  • the extract substance groups are based on ⁇ sa et al. (1994). 10 g of sample are extracted in the Soxhlet extractor with cyclohexane / acetone (9: 1). The extract is made up to 100ml lml extract is added lml standard and at 40 ° C in
  • the standard is a multistandard of heneicosanic acid, cholesterol, cholesteryl palmitate and 1,3-dipalmitoyl-2-oleyl-glycerol.
  • TMCS TMCS
  • the pulp is dissolved in NMMO and then tested by a standard method as described in Schild et al. (2011).
  • the dope is with a constant
  • Viscose filter value the value is multiplied by 10.
  • a Mg bisulfite chemical cell stock (“pulp # 1") was made in a 10L pilot cooker. The boiling was carried out at a temperature of 45 ° C and a H-factor of 75. The total SCk was dosed with 200g / kg of dry wood. For comparison, a prehydrolysis kraft pulp was used
  • Comparative Pulp # 3 also prepared on a pilot scale using conventional VisCBC (continuous batch cooking with steam prehydrolysis) conditions.
  • the steam prehydrolysis was carried out at a temperature of l70 ° C and a P-factor of 600.
  • the boiling took place at an H-factor of 300 at 150 ° C.
  • the effective potassium concentration was 30 g / l.
  • Oxygen bleaching O was carried out at a temperature of 90 ° C, a consistency of 12% and a NaOH addition of 20kg / t pulp over a period of 60min.
  • Ozone dosage in the Z-stage was adjusted to reach the final viscosity.
  • the reaction temperature was 50 ° C.
  • the P-stage was carried out at 70 ° C and lasted for l20min.
  • the following bleaching chemicals were added per ton of pulp: 6.0 kg NaOH, 5.0 kg H 2 O 2 , 5.0 kg MgS0 4 .
  • the two pulps are additionally compared with a commercially available prehydrolysis kraft pulp (the "comparative stock # 1" of Fig. 1).
  • Table 1 Grades of the final bleached bimodal sulphite pulp from pilot cooks as compared to a prehydrolysis Kraft pulp
  • the kappa number is comparable for # 1 pulp and # 3 comparative pulp. By using the same bleaching conditions, # 1 pulp is clearly superior to # 3 in terms of whiteness. Also, the water retention as a measure of the
  • Pore volume and thus the absorbency and accessibility of the pulp for further processing is higher in pulp # 1 than in comparison # 3.
  • the R18 value is lower due to the greatly increased low molecular weight portion of the carbohydrate chains. This is also in the low molecular weight fractions DP ⁇ 50 or ⁇ 100 and at a high PDI visible.
  • the values for pulp # 1 are very high compared to the comparative pulp # 3.
  • FIG. 2 shows the molecular weight distribution of the pilot samples of the new bimodal
  • Digestion process namely made with the acidic magnesium bisulfite process and then with a comparable TCF sequence end bleaching consisting of oxygen, ozone and peroxide bleach.
  • the bimodal pulps of the present invention are well comparable to the market pulp, although the market pulp is from spruce wood and the pulps from the production trials are from beechwood. The viscosities are almost identical.
  • the pulp # 2 attains a high degree of whiteness like the comparative pulp # 2.
  • the whiteness of pulp # 3 at 90.9% is also sufficient.
  • R10, R18 and the ash content are at the same level.
  • the pulps according to the invention from the production experiments differ only by the high acetone extracts of 0.22% and 0.26% and the second low molecular weight maximum in the molecular weight distribution.
  • FIG. 3 shows the molar mass distribution of the sulfite pulps according to the invention in comparison to a sulfite market pulp of comparative pulp # 2.
  • the log values of the low molecular weight maxima of pulps # 2 and # 3 are 3.80 and 3.86, while comparative pulp # 2 has no second low molecular weight peak.
  • the proportion of carbohydrates with a DP ⁇ 100 is slightly increased, the proportion DP ⁇ 50 is 2.5 to 3 times.
  • the polydispersity index for the pulps of the present invention is 5.3 and 5.5 while that of the comparative pulp is 4.1.
  • the high molecular weight fraction is the same for all pulps (compare FIG. 3).
  • the kappa number determination method is generally used to characterize a pulp. It describes the residual content of lignin. In endgebertonen chemical pulps lignin is hardly, so here are more oxidizable
  • the inventive chemical pulps are suitable for the lyocell process, despite an increased content of extractives, specifically throughout all extractant groups (see Table 3).
  • a sulphite pulp made of spruce wood was removed from production after cooking and the first bleaching stage. This pulp was finally bleached with ozone and hydrogen peroxide.
  • the ozone stage was carried out at medium consistency and at 50 ° C.
  • pulp # 4 The resulting pulp of the invention is referred to as "pulp # 4".
  • the bimodal sulfite chemical pulp of the present invention has comparable properties to the market pulp of Comparative Pulp # 2 (see Table 4). Also, a similar level of kappa and whiteness was achieved. Also acetone extract and ash are comparable. Surprisingly, the pulp according to the invention could also be further processed with a high copper number of> 2%. The viscosity of the pulp according to the invention is slightly higher than that of the market pulp in the range required for the lyocell process. Table 4: Properties of the sulfite chemical pulp according to the invention in comparison with a market pulp made of spruce wood
  • Low molecular weight maximum of the inventive pulp # 4 is at a log molecular weight of 3.81 g / mol.
  • the low molecular weight fractions PD ⁇ 50 and ⁇ 100 are significantly higher, while the high molecular weight fraction DP> 2000 is greatly increased.
  • the maxima of the high molecular weight carbohydrates are very close to each other for the investigated pulps. Characterization of the low molecular weight maximum
  • the bimodal chemistry pulps of the invention were prepared from various hardwood and softwoods on a pilot scale and in production trials by means of TCF bleaching.
  • the raw material thus has a different carbohydrate composition.
  • the experimental conditions also vary.
  • log M logarithmic molar masses strongly from each other. They range between 5.23 for pulp # 2 and 5.60 for pulp # 1. Since this is a logarithmic evaluation and presentation, the difference is very clear and is also reflected in the viscosity, which varies between 405 ml / g for pulp # 2 and 580 ml / g for pulp # 1. The differences are extremely evident in the molecular weight of the high molecular weight maximum.
  • pulp # 1 has a maximum at a M of 5.37, the lowest value of pulp # 2 is 4.75 (see Table 6). This corresponds to a degree of polymerization of 1456 or 345.
  • the molecular weight distributions of the low molecular weight carbohydrates are very similar for all pulps investigated.
  • the minimum for a DP is between 51 and 72. This corresponds to a log M of 3.91 and 5.07, respectively.
  • the low molecular maximum lies between a DP of 28 and 44. This corresponds to a log M of 3.66 and 3.86, respectively.
  • the pattern of the new Zehstofftype pulp # 4 on spruce wood basis is exactly in the required range for lyocell application in terms of viscosity (440ml / g).
  • the molecular weight distribution again shows the clear minimum between the two maximum peaks, over which the bimodality is defined, and which allows the determination of the low molecular weight fraction.
  • the mass fraction of low molecular weight carbohydrates below the minimum is 6.1%. This fraction characterizes the increased yield by obtaining the low molecular weight carbohydrates. This results in a significant economic advantage and a more efficient use of the raw material wood and thus a better eco-balance for the entire production chain and the products.
  • pulp # 1 has a low molecular weight content of 8.7% and a hemicellulose content of 5.2% in total. In this pulp so is the low molecular weight Peak significantly larger than the hemicellulose content, ie in the low molecular weight fraction are other polymers such as degraded short-chain cellulose.
  • low-molecular peak also degraded cellulose is to be found and that at the same time hemizelluloses in a longer-chained form can hold, so that they are not to be found in the low-molecular peak.
  • the low molecular weight peak is thus by no means identical to the proportion of hemicelluloses in the pulp
  • the pulp # 4 according to the invention was subjected to a Lyo cell application test.
  • the prehydrolysis kraft pulp from Example 1 comparative pulp # 3
  • two market pulps see Table 7.
  • the fibers produced from the inventive chemical pulps are very well comparable with the fibers produced from the market pulp.
  • the fiber of the bimodal pulp # 4 of the present invention showed a good elongation of 9.4%.
  • the textile strength is below that of the fibers made from the other pulps.
  • Polymers such as in this example adversely affected the strength.
  • the filter value is sufficient. So this pulp is sufficiently easy to process in the application test.
  • the pulps according to the invention are thus suitable for the production of a new fiber type by the fyocell method.
  • M w is the mass average of the molecular mass

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Paper (AREA)

Abstract

L'invention concerne une pâte à usage chimique qui est caractérisée par une combinaison de propriétés : la pâte est fabriquée par un procédé de délignification à base de sulfite ; la pâte présente une répartition bimodale de la masse molaire, une premier maximum de la répartition de masse molaire se situant dans la plage de (à base de g/mol) 4,2 à 6,0 log M, de manière préférée de 4,3 à 5,7, de manière particulièrement préférée de 4,5 à 5,5 et un deuxième maximum de la répartition de masse molaire se situant dans la plage de 3,0 à 4,2 log M, de manière préférée de 3,5 à 4,0, de manière particulièrement préférée de 3,6 à 3,9 ; la pâte présente une moyenne en poids de la masse molaire de 5,0 à 5,5 log Mw, de manière préférée 5,2 à 5,5 ; la pâte présente une teneur en cellulose inférieure à 95 % en poids.
PCT/EP2019/055436 2018-03-06 2019-03-05 Pâte à usage chimique WO2019170667A1 (fr)

Applications Claiming Priority (2)

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EP18160309 2018-03-06
EP18160309.3 2018-03-06

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WO2019170667A1 true WO2019170667A1 (fr) 2019-09-12

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CN115707805A (zh) * 2021-08-18 2023-02-21 上海凯鑫分离技术股份有限公司 一种使用亚硫酸盐蒸煮化学造纸浆生产莱赛尔纤维的方法

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