WO2007132836A1 - 漂白パルプの製造方法 - Google Patents
漂白パルプの製造方法 Download PDFInfo
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- WO2007132836A1 WO2007132836A1 PCT/JP2007/059930 JP2007059930W WO2007132836A1 WO 2007132836 A1 WO2007132836 A1 WO 2007132836A1 JP 2007059930 W JP2007059930 W JP 2007059930W WO 2007132836 A1 WO2007132836 A1 WO 2007132836A1
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- pulp
- acid
- bleaching
- treatment
- chlorine
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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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
- D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
- D21C9/144—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites with ClO2/Cl2 and other bleaching agents in a multistage process
-
- 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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
- D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
-
- 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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
- D21C9/1042—Use of chelating agents
-
- 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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1084—Bleaching ; Apparatus therefor with reducing compounds
-
- 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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
Definitions
- the present invention relates to a method for producing bleached pulp which also has lignocellulosic material strength. More specifically, the present invention relates to a method for producing a bleached pulp, in which bleaching pulp has good discoloration and can reduce the bleaching cost in chlorine-free bleaching or complete chlorine-free bleaching without using molecular chlorine.
- Bleaching of a papermaking noble is carried out by a multi-stage bleaching process.
- chlorine bleaching chemicals have been used as bleaching agents in this multi-stage bleaching.
- C chlorine
- hypochlorite H
- diacid chloride D
- CE-H—D CZD—E—H—E—D
- E means the alkali extraction stage.
- Hexeneuronic acid (hereinafter abbreviated as “HexA”) has a lower ability to remove hexeneuronic acid than chlorine. A large amount of HexA remains. This residual HexA causes deterioration of the discoloration of ECF or TCF bleached pulp.
- HexA is a substance produced by demethanolification of glucuronic acid bound to xylan, which is hemicellulose, present in pulp in the cooking process. Although the effect on the whiteness of the pulp is small, it has a double bond in the molecule, so it reacts with potassium permanganate and is counted as potassium permanganate (K) value or kappa value.
- Patent Document 1 proposes a TCF bleaching method in which peroxomonosulfuric acid is subsequently treated with alkaline hydrogen peroxide.
- Patent Document 2 proposes a bleaching method using a combination of an enzyme and peroxomonosulfuric acid.
- Patent Document 3 proposes a bleaching method by oxygen bleaching, chelating agent treatment, alkaline hydrogen peroxide treatment, and peroxomonosulfuric acid treatment.
- Patent Document 4 proposes a bleaching method performed by a combination of peroxomonosulfuric acid and ozone.
- Patent Document 5 proposes a method of performing peroxomonosulfuric acid treatment after chelating agent treatment and then alkaline hydrogen peroxide treatment in this order! Speak.
- Patent Documents 1 to 5 above are methods relating to the initial delignification treatment in the bleaching step, but nothing is described about HexA removal and fading improvement.
- Patent Document 6 proposes treatment with a peracid and an alkaline earth metal in the final stage of bleaching. Although peracetic acid is used as a peracid, the main purpose of this method is to improve whiteness, and there is no mention of HexA removal or discoloration improvement.
- Patent Document 7 proposes a method of adding a bleaching agent after bleaching and between the preparation steps as a post-treatment after bleaching.
- a bleaching agent after bleaching and between the preparation steps as a post-treatment after bleaching.
- ozone, hydrogen peroxide, peracetic acid, percarbonate, perboric acid, and nitric acid urea are listed as bleaching agents, the main purpose of this method is to improve whiteness, remove HexA, There is no mention of improvement in sex.
- Patent Document 1 Japanese Patent Publication No. 6-505063
- Patent Document 2 Japanese Patent Publication No. 7-150493
- Patent Document 3 Japanese Patent Publication No. 8-507332
- Patent Document 4 Japanese Patent Publication No. 8-511308
- Patent Document 5 JP 10-500178
- Patent Document 6 Special Table 2001-527168
- Patent Document 7 Japanese Unexamined Patent Application Publication No. 2004-169194
- An object of the present invention is to produce a white pulp that improves bleaching of bleached pulp for acidic paper and can reduce the cost of bleaching in chlorine-free bleaching or complete chlorine-free bleaching And a method of providing a paper produced by acid paper making using the bleached pulp.
- pulp that has been subjected to chlorine-free bleaching or complete chlorine-free bleaching after cooking and alkaline oxygen bleaching have found that pulp that has been subjected to chlorine-free whitening or complete chlorine-free bleaching to a predetermined degree of whiteness. Furthermore, it was found that the discoloration of bleached pulp of acidic paper was improved by treatment with peroxomonosulfuric acid, and the second aspect of the present invention was completed.
- Unbleached pulp obtained by digesting lignocellulosic material is bleached with alkaline oxygen, then treated with peroxomonosulfuric acid, and then subjected to multi-stage chlorine-free bleaching that starts with diacid-chlorine treatment power.
- a method for producing bleached pulp is described in detail below.
- the peroxomonosulfuric acid treatment is performed in a combination of a treatment pH of 2 to 5, a treatment temperature of 40 to 70 ° C, and a treatment time of 10 to 200 minutes. Described bleaching pulp manufacturing method
- Unbleached pulp obtained by digesting lignocellulosic material is bleached with alkaline oxygen, then bleached to a whiteness of 70-89% by chlorine-free bleaching or complete chlorine-free bleaching, and then peroxomonosulfuric acid.
- a method for producing bleached pulp characterized by performing a treatment.
- the peroxomonosulfuric acid treatment is performed in a combination of a treatment pH of 3 to 4, a treatment temperature of 40 to 60 ° C., and a treatment time of 2 to 5 hours, (4) to (6) above, The method for producing bleached pulp according to any one of the above.
- the polyvalent carboxylic acid power is at least one selected from oxalic acid, succinic acid, tartaric acid, maleic acid, fumaric acid, phthalic acid, succinic acid, malonic acid, adipic acid and malic acid power.
- the manufacturing method of the bleached pulp in any one of (12).
- the pulp after digestion and alkaline oxygen bleaching is treated with peroxomonosulfuric acid by pretreatment with peroxomonosulfuric acid in the multistage chlorine-free bleaching starting with diacid-chlorine treatment power.
- Diacidification that promotes delignification and removal of HexA Since the delignification and HexA removal action in the chlorine stage is promoted, the amount of expensive chlorine dioxide used in the multi-stage chlorine-free bleaching process can be reduced. HexA remaining in the pulp after bleaching is extremely weak. As a result, it is possible to improve the fading of bleached pulp of acidic paper and reduce the whitening cost.
- the amount of expensive chlorine dioxide or ozone can be increased by treating the pulp after chlorine-free bleaching or completely chlorine-free bleaching with peroxomonosulfuric acid. It is possible to produce bleached pulp using existing facilities for storing bleaching pulp without installing new bleaching facilities. As a result, the discoloration of the bleached pulp of acidic paper can be improved and the bleaching cost can be reduced.
- the lignocellulosic material used in the present invention is not particularly limited, and broad-leaved cocoons, needle cocoons, non-woods such as bamboo and hemp, and mixtures thereof can be used. Among these, hardwood is preferable from the viewpoint of containing a large amount of glucuronic acid that generates HexA.
- known cooking methods such as kraft cooking, polysulfide cooking, soda cooking, alkali sulfite cooking, etc. can be used. However, pulp quality, energy efficiency, etc. can be used. Considering this, kraft cooking or polysulfide cooking is preferably used.
- the kraft cooking liquor when kraft cooking 100% lignocellulosic hardwood, the kraft cooking liquor usually has a sulfur content of 5 to 75%, preferably 15 to 45%, and the effective alkali addition rate is absolutely dry wood. Usually 5 to 30% by mass, preferably 10 to 25% by mass, and the cooking temperature is usually 130 to 170 ° C, preferably 140 to 160 ° C.
- the digestion method using a modified digestion method in which a digestion solution is added at multiple points.
- cyclic keto compounds for example, benzoquinone, naphthoquinone, anthraquinone, anthrone, phenanthroquinone, and nuclear substitutes such as alkyl and amino of the quinone compounds
- it is a hydroquinone compound such as anthrahydroquinone, which is a reduced form of the quinone compound, and a stable compound obtained as an intermediate for the synthesis of anthraquinone by the Diels Alda method 9, 10 —
- One or more selected diketohydroanthracene compounds may be added, and the addition rate is a normal addition rate, for example, 0.000 per absolute dry mass of wood chips. ⁇ 1.0% by mass.
- unbleached pulp obtained by a known digestion method is subjected to washing, rough selection and fine selection processes, and then delignified by a known alkaline oxygen bleaching method.
- a known medium concentration method or high concentration method can be applied as it is, but it is currently used for general purposes and has a medium concentration at a pulp concentration of 8 to 15% by mass. The law is preferred.
- caustic soda or oxidized kraft white liquor can be used as the alkali
- oxygen gas from the cryogenic separation method PSA (Pressure Oxygen from Swing Adsorption, VSA (Vacuum Swing Adsorption) force, etc. can be used.
- the oxygen gas and alkali are added to a medium-concentration mixer in a medium-concentration mixer and mixed thoroughly. After that, the reaction mixture is maintained in a reaction tower capable of holding a mixture of pulp, oxygen, and alkali for a certain period of time under pressure. Sent and delignified.
- the addition rate of oxygen gas is usually 0.5 to 3% by mass, preferably 1.0 to 2.5% by mass
- the alkali addition rate is usually 0.5 to 4% by mass, preferably 0.5 to 4% by mass, based on the mass of the dry pulp.
- reaction temperature is usually 80 to 120 ° C, preferably 90 to 110 ° C
- reaction time is usually 15 to: LOO minutes, preferably 30 to L00 minutes
- pulp concentration is usually 8 to 15% by mass. Other known conditions can be applied.
- the alkali oxygen bleaching is continuously performed a plurality of times, delignification is advanced as much as possible, and the heavy metal content is reduced.
- the pulp that has been subjected to alkaline oxygen bleaching should be washed in the next step.
- the method for producing peroxomonosulfuric acid used in the present invention is not particularly limited. For example, it can be produced by hydrolyzing peroxydisulfuric acid, or can be produced by mixing hydrogen peroxide and sulfuric acid at an arbitrary ratio. Also, use something like oxone which is a double salt of peroxomonosulfuric acid (2KHSO -KHSO ⁇ ⁇ SO)
- peroxomonosulfuric acid As a method for producing peroxomonosulfuric acid by mixing peroxyhydrogen and sulfuric acid, it is usually 20 to 70% by mass, preferably 35 to 60% by mass in peroxyhydrogen water. A method in which ⁇ 98% mass%, preferably 93 to 96% by mass of concentrated sulfuric acid is dropped and mixed is suitable.
- the mixing molar ratio of sulfuric acid and hydrogen peroxide is usually 1: 1 to 5: 1, preferably 2: 1 to 4: 1. If the concentration of both hydrogen peroxide and sulfuric acid is within the above range, the production efficiency of peroxosulfuric acid can be improved and the risk of ignition and the like can be suppressed.
- the first aspect is a method of performing a multi-stage chlorine-free bleaching process starting from chlorine dioxide treatment after being sent to the peroxomonosulfuric acid treatment stage after the above alkali oxygen bleaching.
- the addition rate of peroxosulfuric acid is usually 0.01 to 2% by mass based on the mass of the absolutely dry pulp, preferably 0. It is 1-1 mass%.
- the treatment pH is usually 1.5 to 6, preferably pH 2 to 5.
- the treatment time is usually 1 minute to 5 hours, preferably 10 minutes to 200 minutes.
- the treatment temperature is usually 20 ° C to 90 ° C, preferably 40 ° C to 70 ° C.
- the pulp concentration is usually 5-30%, preferably 8-15%.
- the treatment pH is particularly important, and it is usually carried out in the pH range of 5 to 6, preferably 2 to 5.
- the treatment pH is in the range of 1.5 to 6.0, it has a delignification action almost constant.
- the decomposition action of HexA becomes maximum near pH 3, and the action gradually decreases when the pH deviates from 3. Therefore, in order to sufficiently decompose HexA, the pH is preferably 5 or less.
- the pH is preferably 2 or more.
- the viscosity after peroxomonosulfuric acid treatment can be kept high without performing pretreatment for removing metal ions such as chelate treatment.
- diacid / chlorine bleaching can be performed without alkali extraction.
- the pulp after the treatment with peroxomonosulfuric acid is preferably washed.
- the components in the pulp decomposed and eluted during the treatment with peroxomonosulfuric acid are not carried over to the multi-stage chlorine-free bleaching process, and the ingredients and bleaching chemicals such as chlorine dioxide are mixed in the bleaching stage. It is possible to prevent the bleaching agent from being wasted due to the reaction.
- the type and number of washing machines used in the washing stage are not particularly limited, but a press type can be preferably used because of high washing efficiency. After washing, the pulp is sent to a multi-stage chlorine-free bleaching process.
- a chlorine dioxide bleaching stage is always inserted in the first stage of the multistage chlorine-free bleaching process.
- Treatment with peroxosulfuric acid and washing treatment reduce the amount of HexA in the pulp and promote HexA removal at the chlorine dioxide stage, so even if a large amount of chlorine dioxide is not used, it is multistage chlorine-free.
- the amount of HexA in the pulp after the bleaching process can be reduced.
- the chlorine dioxide bleaching conditions are not particularly limited, and known conditions can be used.
- the addition ratio of diacid and chlorine is 0.1 to 2% by mass, preferably 0.3 to 1.5% by mass, and the reaction temperature is usually 30 to 80 ° C., preferably The reaction time is 40 to 70 ° C, the reaction time is 5 to 180 minutes, preferably 30 to 120 minutes, and the reaction pH is 2.0 to 6.0, preferably 2.0 to 4.
- Known alkalis and acids can be used for pH adjustment.
- the pulp concentration is not particularly limited, but is preferably 8 to 15% by mass from the viewpoint of operability.
- the multistage chlorine-free bleaching step is not particularly limited except that the first stage is a diacid-chlorine stage, but the second stage is an alkali extraction stage, and the third and subsequent stages. Is preferably a combination of a chlorine dioxide bleaching stage and an alkaline peroxyhydrogen bleaching stage.
- the alkali addition rate is usually 0.5 to 3% by mass, preferably 0.5 to 2.0% by mass, and the reaction temperature is usually 60 to 120 ° C., preferably 60 to 80 ° C, reaction time is usually 15 to 120 minutes, and pulp concentration is usually 8 to 15% by mass.
- oxygen gas is added to the alkali extraction stage.
- the addition rate of oxygen gas is usually 0.1 to 3% by mass, preferably 0.1 to 1.0% by mass, based on the mass of the absolutely dry pulp.
- hydrogen peroxide is also added.
- the addition rate of hydrogen peroxide is usually 0.05 to 2% by mass, preferably 0.1 to 1.0% by mass, based on the mass of the dry pulp.
- the peracid-hydrogen addition rate is usually 0.05-2 mass%, preferably 0.1-1.0 mass%, and the reaction temperature Usually 60 to 120 ° C, preferably 60 to 90 ° C, reaction time is usually 15 to 180 minutes, preferably 30 to 180 minutes, pH is usually 10.5 to 12.0, preferably 11 to 11.5. It is preferable to do.
- Known alkalis and acids can be used for pH adjustment.
- the pulp concentration is not particularly limited, but it is preferably 8 to 15% by mass from the viewpoint of operability.
- the diacid / chlorine addition rate is usually 0.1 to 1% by mass, preferably 0.1 to 0.5% by mass based on the absolute dry mass of the nord.
- the reaction temperature is usually 60 to 120 ° C, preferably 60 to 80 ° C
- the reaction time is usually 15 to 300 minutes, preferably 60 to 180 minutes
- the pH is usually 3.0 to 6.0, Preferably it should be between 4 and 5.5.
- Known alkalis and acids can be used for pH adjustment.
- the pulp concentration is not particularly limited, but the operability point is preferably 8 to 15% by mass.
- the second aspect is a method of applying a chlorine-free bleaching treatment or a complete chlorine-free bleaching treatment and then a peroxosulfuric acid treatment after the alkali oxygen bleaching described above.
- a chlorine-free bleaching treatment or a complete chlorine-free bleaching treatment and then a peroxosulfuric acid treatment after the alkali oxygen bleaching described above.
- pulp bleached to a whiteness of 70 to 89% by chlorine-free bleaching or complete chlorine-free bleaching treatment is used for peroxomonosulfuric acid treatment.
- Chlorine-free bleaching sequences include D—Ep—D, D—Eop—D, D—Ep—P—D, D—Eop—P—D, D—Ep—D—D ⁇ D—Eop—D—D.
- D—Ep— D—P, D—Eop— Chlorine dioxide-based ECF bleaching sequence such as DP, Z—Ep-D, Z-Eop-D, Z Ep—P—D ⁇ Z—Eop—P— D ⁇ Z— Ep— D— D ⁇ Z— Eop— D— D, Z— Ep— D— P, ozone-based ECF bleaching sequences, ZZD— Ep— D, ZZD— Eop— D, Z / D-Ep-PD, ZZD— Eop— P— D ⁇ Z, D— Ep— D— D ⁇ Z / D— Eop— D -D, Z / D-Ep-DP, ZZD— Eop— D— P Z—Ep—P, Z—Eop—P, Z—Ep—P—P, Z—Eop—P—P, Z — Ep— Q— P ⁇ Z-Eop-QP
- the whiteness of the pulp bleached by the above chlorine-free bleaching sequence or the complete chlorine-free bleaching sequence is 70 to 89%, preferably 80 to 87%, from the viewpoint of the balance between whiteness improvement and bleaching cost. .
- the K value and HexA content which are indicators of the color fading of the pulp, the better.
- a large amount of bleaching agent is required for this purpose, and there are problems of pulp viscosity reduction and cost increase. Therefore, as a suitable pulp physical property for the method of the present invention that can solve both the problems of pulp fading and bleaching cost, the K value is preferably 1.5 or more, and the HexA amount is preferably 10 ⁇ molZ. Pulp g or more.
- Pulp bleached to the desired whiteness, K value, and HexA amount in the above chlorine-free bleaching sequence or complete chlorine-free bleaching sequence is sent to the peroxomonosulfuric acid treatment step.
- washing is preferably performed before the peroxomonosulfuric acid treatment step.
- the addition rate of peroxosulfuric acid is usually 0.01 to 2 mass% per mass of the dry pulp, and preferably 0. 1 to 1 weight 0/0.
- the treatment pH is usually 1.0 to 12.0, preferably 1.0 to 6.0, more preferably 2.0 to 4.0.
- the treatment time is usually 10 minutes to 12 hours, preferably 30 minutes to 6 hours, and more preferably 2 to 5 hours.
- the treatment temperature is usually 40 ° C to 100 ° C, preferably 45 ° C to 70 ° C, more preferably 40 ° C to 60 ° C.
- the pulp concentration is usually 5 to 30%, and a higher pulp concentration is preferred, preferably 10 to 30%.
- a viscosity decrease may rarely occur.
- a method for suppressing the decrease in viscosity it can be avoided by performing peroxomonosulfuric acid treatment at low temperature for a long time or adjusting the pH after peroxomonosulfuric acid treatment. That is, the viscosity reduction can be suppressed by setting the peroxomonosulfuric acid treatment temperature to 40 to 60 ° C. and the treatment time to 2 to 5 hours.
- a viscosity fall can be suppressed by adding a well-known alkali and an acid so that pH after a peroxosulfuric acid process may become the range of 3-4. Processing temperature, processing time, and processing pH are within the above range. By adjusting to, the effect of suppressing the decrease in viscosity can be exhibited more.
- chelating agents include ethylenediamine amine acetic acid (EDTA) and diethylenetriaminepentaacetic acid.
- Carboxylic acid types such as (DTP A), nitrite triacetic acid (NTA), 1-hydroxyethylidene — 1, 1-diphosphonic acid (HEDPA), ethylenediaminetetra (methylenephosphonic) acid (ED TMPA), diethylenetria
- NTA nitrite triacetic acid
- HEDPA 1-hydroxyethylidene — 1, 1-diphosphonic acid
- ED TMPA ethylenediaminetetra (methylenephosphonic) acid
- diethylenetria examples include phosphonic acid types such as minpenta (methylenephosphonic acid) (DTPMPA) and nitrotri (methylenphosphonic acid) (NTMPA).
- the amount of the chelating agent used is usually in the range of 0.02-0.3%, preferably 0.02-0.2% (as a mass% of the pulp).
- the amount of the chelating agent used is 0.3% or more, the ability to remove HexA by peroxomonosulfuric acid decreases, and when it is 0.02% or less, the decrease in the pulp viscosity cannot be suppressed.
- polyvalent carboxylic acid examples include oxalic acid, succinic acid, tartaric acid, maleic acid, fumaric acid, phthalic acid, citrate, malonic acid, adipic acid, malic acid and the like.
- the amount of polyvalent carboxylic acid used is preferably in the range of 0.02% to 0.3% (as a mass% of pulp).
- the amount of polyvalent carboxylic acid used is 0.3% or more, the ability to remove HexA by peroxosulfuric acid is reduced, and when it is 0.02% or less, the decrease in pulp viscosity cannot be suppressed.
- a range of 0.02% to 0.3% (as a mass% of the pulp) is preferable.
- the amount of the mixture used is 0.3% or more, the HexA removal ability of peroxomonosulfuric acid is lowered, and when it is 0.02% or less, the decrease in pulp viscosity cannot be suppressed.
- the bleaching norp obtained by the production method of the present invention may be sent as it is to the papermaking process through the storage tank process or may be sent to the papermaking process after pH adjustment. Since the bleaching pulp has undergone the peroxomonosulfuric acid treatment process, it is preferably sent to the acidic papermaking process.
- the paper of the present invention is usually produced at a pH of 6 or less in the acidic papermaking process.
- the first feature of the present invention is that, when converted from conventional chlorine bleaching to chlorine-free bleaching or complete chlorine-free bleaching, especially in the case of hardwood pulp, a large amount of HexA related to paper fading is present in bleached pulp.
- the conventional method must use a large amount of chlorine dioxide and ozone, resulting in increased chemical costs and whiteness. There was a problem such as too high.
- peroxomonosulfuric acid treatment is performed before chlorine-free bleaching or after chlorine-free bleaching or after chlorine-free bleaching without increasing chlorine dioxide and ozone.
- the amount of HexA remaining in the bleached pulp can be reduced, and the peroxomonosulfuric acid treatment can be efficiently carried out using facilities such as storage tanks before and after non-chlorine bleaching.
- the second feature is that when peroxomonosulfuric acid treatment is applied to the previous stage of chlorine-free bleaching, the efficiency of the next stage chlorine dioxide treatment is improved, and the amount of chlorine dioxide can be reduced.
- the third feature is that, when peroxomonosulfuric acid treatment is applied after chlorine-free bleaching or complete chlorine-free bleaching, Hex A can be removed at a small chemical cost with a small amount of residual HexA in the bleaching norp. It is.
- the fourth feature is that a decrease in pulp viscosity due to peroxomonosulfuric acid treatment can be completely suppressed by using a chelating agent and Z or polyvalent carboxylic acid in combination with peroxomonosulfuric acid treatment.
- the production method of the present invention is a peroxomonosulfuric acid that can be produced from an inexpensive raw material by an inexpensive method as an improvement measure for the deterioration of the fading of paper produced by acid-free paper from chlorine-free bleached pulp or completely chlorine-free bleached pulp. Can be used economically and efficiently to remove HexA, and as a result, the above-mentioned fading can be improved.
- the measurement of monovalent kappa was performed according to JIS P 8211.
- the potassium permanganate value was measured according to TAPPI UM 253.
- the Norp viscosity was measured according to the J. TAPPI No. 44 method.
- a sheet having a basis weight of 60 g / m 2 was prepared according to JIS P 8209, and the whiteness of the pulp was measured according to JIS P 8148.
- Preparation of sheet After the bleached pulp was disaggregated, aluminum sulfate was added to adjust the pH to 4.5, and then a sheet with a basis weight of 60 gZm 2 was prepared and dried overnight at room temperature in a blow dryer. This sheet was faded for 24 hours under conditions of 80 ° C. and relative humidity 65%, and the PC value (acidity) was calculated from the whiteness before and after the fade according to the following formula to evaluate the fading property of the pulp. In general, if the PC value is 4.5 or less, it can be evaluated that there is no problem with the fading of the pulp.
- PC value [ ⁇ (Whiteness after 1 fade) V (2 X Whiteness after fade) 2 ⁇ — ⁇ (1 Whiteness before fade) 2 Z (2 X Whiteness before fade) 2 ⁇ ] X 100
- Absolute dry weight 70 Og of the unbleached kraft pulp was collected, 2.0% of caustic soda per absolute dry pulp mass was added, and then diluted with ion-exchanged water to adjust the pulp concentration to 10%.
- alkaline oxygen bleaching is performed in an upflow state in a 50 m high columnar reaction vessel, and 99.9% of commercially available compressed oxygen gas is injected to adjust the gauge pressure to IMPa.
- the reaction was carried out at 95-100 ° C for 50 minutes while venting the gas so that the gauge pressure decreased at a rate of 0. OlMPa per minute.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 sulfuric acid was added at 0.6% per mass of dry pulp during peroxomonosulfuric acid treatment to change the pH during peroxomonosulfuric acid treatment to 2.0, and the rate of addition of chlorine dioxide in stage D1 The same operation as in Example 1 was performed, except that was changed to 0.65%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.8%
- the kappa monovalent was 8.5
- the pulp viscosity was 19.7 mPa's
- the whiteness of the bleached pulp was 85.9%
- 1 ⁇ Value is 1.0
- HexA amount is 5 O / z molZ Norep g
- viscosity was 13.8 mPa.s
- PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 sulfuric acid was added at 2.0% per mass of dry pulp during peroxomonosulfuric acid treatment to change the pH during peroxomonosulfuric acid treatment to 1.5, and the rate of addition of chlorine dioxide in stage D1 The same operation as in Example 1 was performed, except that was changed to 0.7%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.5%
- the kappa monovalent was 8.7
- the pulp viscosity was 18.8 mPa's
- the whiteness of the bleached pulp was 85.8%
- 1 ⁇ Value is 1.1
- HexA content is 5.3 / z molZ norp g
- viscosity is 13.2 mPa.s
- PC value is 3. Met.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 caustic soda was added at 0.4% per mass of dry pulp during peroxomonosulfuric acid treatment to change the pH during peroxomonosulfuric acid treatment to 5.0, and diacid in D1 stage. The same operation as in Example 1 was carried out except that the chlorine addition rate was changed to 0.65%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 55.3%, the kappa monovalent was 8.4, the pulp viscosity was 20.9 mPa's, and the whiteness of the bleached pulp was 85.8%, 1: The value was 1.0, the amount of HexA was 5 .: mol / pulp g, the viscosity was 16.2 mPa's, and the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 0.6% of caustic soda was added per weight of absolutely dry pulp during peroxomonosulfuric acid treatment to change the pH during peroxomonosulfuric acid treatment to 6.0, and diacid in D stage. The same operation as in Example 1 was performed, except that the chlorine addition rate was changed to 0.7%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 55.8%, the kappa monovalent was 8.9, the pulp viscosity was 21.5 mPa's, and the whiteness of the bleached pulp was 85.9%, 1: The value was 1.2, the amount of HexA was 5.5 111017 pulp 3, the viscosity was 16.7 mPa's, and the PC value was 3.1.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the assumption of alkaline oxygen bleaching in an upflow state in a 50 m high columnar reaction vessel is assumed, and two steps of alkaline oxygen bleaching using two 25 m high columnar reaction vessels.
- the gauge pressure is IMPa by injecting 99.9% of commercially available compressed oxygen gas and degassing at a rate of 0. OlMPa every minute for 25 minutes at 95 ° C. Then, 99.9% of commercially available compressed oxygen gas was injected to make the gauge pressure IMP a, and the gas was evacuated to reduce the gauge pressure at a rate of 0. OlMPa per minute.
- the same operation as in Example 1 was carried out except that the reaction was performed at C for 25 minutes and the chlorine dioxide addition rate in the D1 stage was changed to 0.5%.
- the whiteness of the pulp after alkaline oxygen bleaching was 52.5%, the kappa monovalent was 8.9, the pulp viscosity was 22. OmPa's, and the whiteness of the pulp after peroxomonosulfuric acid treatment was 56.5%.
- Force Bopper value is 7.7, pulp viscosity is 19.6 mPa's, whiteness of bleached pulp is 86.0%, K value is 0.9, HexA content is 4.6 ⁇ molZ pulp g, viscosity Of 16.2 mPa's and PC value of 2.7.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that washing after the peroxomonosulfuric acid treatment was not performed and the D1 stage was 0.65%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 55.0%
- the kappa monovalent was 8.4
- the pulp viscosity was 20.2 mPa's
- the whiteness of the bleached pulp was 86.0%
- K The value was 1.0
- the amount of HexA was 5.1 ⁇ molZ pulp g
- the viscosity was 14. lmPa's
- the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the temperature during treatment with peroxomonosulfuric acid was 40 ° C, and D1 stage was 0.65. The same operation as in Example 1 was performed except that% was set.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.8%, the kappa monovalent was 8.6, the pulp viscosity was 20.8 mPa's, and the whiteness of the bleached pulp was 85.9%, 1: The value was 1.0, the amount of HexA was 5.0 molZ pulp g, the viscosity was 14.5 mPa's, and the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that the peroxomonosulfuric acid treatment was performed at 25 ° C. and the D1 stage was changed to 0.75%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.1%
- the kappa monovalent was 8.9
- the norpe viscosity was 22. ImPa's
- the whiteness of the bleaching pulp was 86.1%.
- the 1 ⁇ value was 1.0
- the amount of HexA was 5.0 / z molZ pulp g
- the viscosity was 15.3 mPa's
- the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that the peroxomonosulfuric acid treatment was performed at 70 ° C and the D1 stage was 0.6%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 55.2%, the kappa monovalent was 8.4, the pulp viscosity was 19.6 mPa's, and the whiteness of the bleaching pulp was 86.2%, 1
- the ⁇ value was 1.0, the amount of HexA was 4.8 molZ norp g, the viscosity was 13.9 mPa's, and the PC value was 2.8.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that the peroxomonosulfuric acid treatment was performed at 90 ° C. and the D1 stage was 0.65%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.3%, the kappa monovalent was 8.8, the pulp viscosity was 17.9 mPa's, and the whiteness of the bleaching pulp was 85.8%, 1
- the ⁇ value was 1.0
- the amount of HexA was 5.2 / z molZ pulp g
- the viscosity was 12.8 mPa's
- the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that the peroxomonosulfuric acid treatment time was 10 minutes and the D1 stage was 0.65%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.9%, the kappa monovalent was 8.6, the pulp viscosity was 20.5 mPa's, and the whiteness of the bleached pulp was 85.7%, 1
- the ⁇ value was 1.0, the amount of HexA was 5.2 molZ pulp g, the viscosity was 15. OmPa's, and the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same procedure as in Example 1 was performed, except that the peroxomonosulfuric acid treatment time was 5 minutes and the D1 stage was 0.7%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.0%, the kappa monovalent was 8.9, the norpe viscosity was 21.2 mPa's, and the whiteness of the bleaching pulp was 86.1%.
- the value was 1.0, the amount of HexA was 5.2 / z molZ pulp g, the viscosity was 1 5. OmPa's, and the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same procedure as in Example 1 was performed, except that the peroxomonosulfuric acid treatment time was 200 minutes and that the D1 stage was 0.6%.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.7%
- the kappa monovalent was 8.3
- the pulp viscosity was 19.4 mPa's
- the whiteness of the bleached pulp was 85.8%
- K The value was 1.0
- the amount of HexA was 4.8 ⁇ molZ pulp g
- the viscosity was 13.7 mPa's
- the PC value was 2.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the peroxomonosulfuric acid treatment time was 300 minutes, and D1 stage was 0.6%. The same operation as in Example 1 was performed except that.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.2%, the kappa monovalent was 8.2, the pulp viscosity was 17. ImPa's, and the whiteness of the bleached pulp was 85.5%, 1
- the ⁇ value was 0.9
- the amount of HexA was 4.7 molZ pulp g
- the viscosity was 12.6 mPa's
- the PC value was 2.8.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that 0.1% of EDTA as a chelating agent was added to the pulp during the peroxomonosulfuric acid treatment.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.8%
- the kappa monovalent was 8.5
- the norpe viscosity was 20.
- OmPa-s the whiteness of the bleached pulp was 85.8%.
- the value was 1.2
- the amount of HexA was 5.5 molZ pulp 3
- the viscosity was 14.
- OmPa's the PC value was 3.1.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 3 the same operation as in Example 3 was performed, except that 0.1% of EDTA as a chelating agent was added to the pulp during the peroxomonosulfuric acid treatment.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.6%
- the kappa monovalent was 8.7
- the norpe viscosity was 20.2 mPa-s
- the whiteness of the bleached pulp was 85.8%.
- the value was 1.1
- the amount of HexA was 5.2 / z molZ pulp g
- the viscosity was 14. lmPa's
- the PC value was 3.1.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 3 the same operation as in Example 3 was performed, except that 0.1% of oxalic acid as a polyvalent carboxylic acid was added to the pulp during the peroxomonosulfuric acid treatment.
- the whiteness of the pulp after peroxomonosulfuric acid treatment was 54.7%
- the kappa monovalent was 8.6
- the pulp viscosity was 20. m Pa's
- the whiteness of the bleached pulp was 85.9%
- 1 The ⁇ value was 1.1
- the amount of HexA was 5.0 mol Z-pulp g
- the viscosity was 14. lmPa's
- the PC value was 3.0.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the same operation as in Example 1 was performed, except that the peroxomonosulfuric acid treatment was not performed and the chlorine dioxide-added calorie rate in stage D1 was changed to 0.8%.
- the bleached pulp had a whiteness of 85.8%, a K value of 2.2, a HexA content of 10.3 ⁇ molZ pulp g, a viscosity of 16. OmPa's, and a PC value of 6.9.
- Table 1 shows the pH during peroxomonosulfuric acid treatment, the properties of the treated pulp (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value.
- Example 1 the alkali oxygen bleaching time was extended to 70 minutes to obtain a pulp having a whiteness of 55.1%, a copper number of 8.4, and a pulp viscosity of 20.6 mPa's.
- the pulp was subjected to the same bleaching operation as in Example 1 except that no peroxosulfuric acid treatment was performed.
- the bleaching pulp had a whiteness of 86.0%, a 1 ⁇ value of 1.5, a HexA content of 6.2 / z molZ pulp g, a viscosity of 15.3 mPa's, and a PC value of 3.4. .
- Table 1 shows the properties (whiteness, kappa monovalent, viscosity), total chlorine dioxide addition rate, K value, HexA amount and PC value of the pulp before D1 stage bleaching.
- Example 1 3.0 60 60 55.0 8,4 20.2 0.80 86.0 1.0 4.9 14.1 2.9
- Example 2 2.0 60 60 54.8 8.5 19.7 0.85 85.9 1.0 5.0 13.8 2.9
- Example 3 1.5 60 60 54.5 8.7 18.8 0.90 85.8 1.1 5.3 13.2 3,0
- Example 4 5.0 60 60 55.3 8.4 20.9 0.85 85.8 1.0 5.1 16.2 2.9
- Example 5 6.0 60 60 55.8 8.9 21.5 0.90 85.9 1.2 5.5 16.7 3.1
- Example 6 3.0 60 60 56.5 7.7 19.6 0.70 86.0 0.9 4.6 16.2 2.7
- Example 7 3.0 60 60 55.0 8.4 20.2 0.85 86.0 1.0 5.1 14.1 2.9
- Example 9 3.0 60 25 54.1 8.9 22.1 0.95 86.1 1.0 5.0 15.3 2.9
- Example 10 3.0 60 70 55.2 8.4 19.6 0.80 86.2
- the amount of the oxyhydride group can be reduced. As a result, the bleaching cost can be reduced as a result. Furthermore, it can be seen that by providing a peroxomonosulfuric acid treatment stage before the ECF bleaching step, it is possible to greatly reduce the amount of HexA contained in the pulp having the desired whiteness. As a result, the PC value can be greatly reduced and the fading property can be improved.
- Example 7 Further, comparing Example 1 and Example 7, it can be seen that the effect is increased by performing the washing after the peroxomonosulfuric acid treatment stage.
- Example 1 24 and Example 35 it can be seen that the effect is increased by setting the pH of the peroxomonosulfuric acid treatment stage to 25.
- Example 1 8 10 and 9 11 the treatment temperature of the peroxomonosulfuric acid treatment stage was increased to 40 ° C and 70 ° C, and the effect was increased, and the pulp quality was not impaired. It is possible that you can do this.
- Examples 1, 12, and 14 with Examples 13 and 15 increasing the treatment time of the peroxomonosulfuric acid treatment stage to 10 to 200 minutes increases the effect and further improves the pulp quality. The fact that processing can be carried out without loss is astonishing.
- the combination of conditions of the peroxomonosulfuric acid treatment stage is pH 2-5, treatment temperature 40-70 ° C, treatment time 10-200 minutes, and the treatment is most effective and without impairing the pulp quality. Can do.
- Example 3 when comparing Example 3 with Examples 17 and 18, the problem that the Norp viscosity is lowered when the pH after peroxomonosulfuric acid treatment is 1.5, ED TA or It turns out that a viscosity fall can be suppressed by adding a citric acid.
- Example 1 Compared Example 1 and Example 6, it can be seen that the effect is further increased by performing the alkali oxygen bleaching in multiple stages.
- Example 1 Comparative Example 2
- the removal amount of HexA during multi-stage bleaching increases by providing a peroxomonosulfuric acid treatment stage before multi-stage bleaching.
- the pulp used was L-wood pulp A that had been subjected to oxygen delignification by kraft cooking-alkali oxygen bleaching.
- the properties of panolep A are shown below.
- First stage D 0.6% chlorine dioxide was added to Pulp A and treated for 60 minutes under conditions of 10% pulp concentration and 60 ° C temperature. After completion of the reaction, it was diluted with clean water (filtered tap water) to a pulp concentration of 2.5%, and then dehydrated and washed to a pulp concentration of 20%.
- Eop 1.0% of caustic soda, 0.15% of oxygen and 0.3% of hydrogen peroxide were added to the pulp after the above first stage D, and the pulp concentration was 10% and the temperature was 60 ° C. Minute processed. After completion of the reaction, it was diluted with clean water (filtered tap water) to a pulp concentration of 2.5%, and then dehydrated and washed to a pulp concentration of 20%.
- Final stage D 0.3% of sodium diacid chloride was added to the pulp after the Eop stage and treated for 180 minutes under conditions of a pulp concentration of 10% and a temperature of 70 ° C.
- the obtained norp was diluted with clean water (filtered tap water) to a pulp concentration of 2.5%, and then dehydrated and washed to a pulp concentration of 20%.
- the washing step performed after the bleaching of each stage was carried out at a washing rate of 89.6%.
- the washing rate represents how much the liquid in the pulp after bleaching is replaced by the washing liquid.
- the solution is 900 g in 100 g of bleached pulp
- 3000 g of washing solution can be added to this pulp to obtain a pulp concentration of 2.5%.
- this pulp is dewatered to a pulp concentration of 20%, the liquid in the nolep becomes 400 g.
- Peroxomonosulfuric acid treatment The ratio of peroxosulfuric acid obtained in Production Example 2 shown in Table 2 to the pulp after the final stage D (0.3%, 0.6%, 0.9%, 1. 2%, 1.5%) and treated for 120 minutes under conditions of a norp concentration of 20% and a temperature of 70 ° C. to obtain bleached pulp.
- Table 2 shows the amount of peroxomonosulfuric acid added, the whiteness of the bleached pulp, the K value, the amount of HexA, the viscosity, and the PC value (acidic).
- bleaching was performed according to the following bleaching conditions according to the D—E o—D bleaching sequence to obtain bleached pulp.
- First stage D Add 1.1% chlorine dioxide to pulp A, pulp concentration 10%, temperature 60 ° C Treated for 60 minutes. After completion of the reaction, it was diluted with clean water (filtered tap water) to a pulp concentration of 2.5%, and then dehydrated and washed to a pulp concentration of 20%.
- Eo The pulp after the first stage D was added with 0.8% caustic soda and 0.15% oxygen and treated for 60 minutes under the conditions of a pulp concentration of 10% and a temperature of 60 ° C. After completion of the reaction, it was diluted with clean water (filtered tap water) to a pulp concentration of 2.5%, then dehydrated and washed to a pulp concentration of 20%.
- Table 2 shows the whiteness, K value, HexA content, viscosity, and PC value (acidity) of the bleaching norp.
- a bleaching pulp was obtained according to the D—Eop—D bleaching sequence in the same manner as in Comparative Example 3 except that 0.3% of the chlorine dioxide in Stage D was added.
- Table 2 shows the whiteness, K value, HexA content, viscosity, and PC value (acidity) of the bleached pulp.
- the diacid-chlorine-based ECF bleaching (Comparative Example 3), which does not use peracid-hydrogen, is generally considered to have no problem with fading, K value 1.5 or less, PC value 4.
- a large amount of chlorine dioxide is required to obtain a bleaching pulp of 5 or less.
- there are problems such as excessive whiteness and increased bleaching costs.
- hydrogen peroxide was used.
- the amount of residual HexA with a high K value increases and the acidic PC value deteriorates as a result.
- Bleached with D-Eop-D bleaching sequence in the same manner as in Comparative Example 4, except that 0.70% of chlorine dioxide in the first stage D and 0.25% of hydrogen peroxide in the Eop stage were added.
- Bleached pulp Got. Table 3 shows the whiteness, K value, HexA content, viscosity, and PC value (acidity) of the bleached pulp.
- Bleaching was performed using the D-Eop-D bleaching sequence in the same manner as in Comparative Example 4, except that 0.9% of chlorine dioxide in the first stage D and 0.15% hydrogen peroxide in the Eop stage were added. Bleached pulp was obtained.
- Table 3 shows the whiteness, K value, HexA content, viscosity, and PC value (acidity) of the bleached pulp.
- Example 26 In the same manner as in Comparative Example 7, chlorine-free bleaching was performed using a D-Eop-D bleaching sequence. Further, 0.1% peroxomonosulfuric acid was added to the obtained pulp and treated for 120 minutes under the conditions of a norp concentration of 20% and a temperature of 70 ° C. to obtain a bleached pulp. Table 4 shows the whiteness, K value, HexA content, viscosity, and PC value (acidity) of the bleaching norp.
- peroxymonosulfuric acid with acid papermaking pulp, it is possible to use peroxyhydrogen peroxide which is less expensive than chlorine-free bleaching, and as a result, it is possible to produce cheap chlorine-free bleached pulp.
- a bleached pulp was obtained in the same manner as in Example 20, except that 0.1% each of DTPA, EDTA, NTA, EDTMPA, and DTPMPA chelating agents were used in combination with peroxomonosulfuric acid in Example 20.
- Table 5 shows the whiteness, K value, HexA content, and viscosity of the bleached pulp.
- a bleached pulp was obtained in the same manner as in Example 27 except that a combination of% and 0.5% was used.
- Table 6 shows the whiteness, K value, HexA content and viscosity of the bleached pulp.
- a bleached pulp was obtained in the same manner as in Example 28 except that a combination of 0.5% and 0.5% was used.
- Table 6 shows the whiteness, K value, HexA content and viscosity of the bleached pulp.
- Example 20 except that 0.1% of each of oxalic acid, succinic acid, fumaric acid, maleic acid, phthalic acid, tartaric acid, succinic acid, malonic acid, adipic acid and malic acid was used in combination with peroxomonosulfuric acid treatment.
- 0.1% of each of oxalic acid, succinic acid, fumaric acid, maleic acid, phthalic acid, tartaric acid, succinic acid, malonic acid, adipic acid and malic acid was used in combination with peroxomonosulfuric acid treatment.
- Table 7 shows the whiteness, K value, HexA content and viscosity of the bleached pulp.
- a bleached pulp was obtained in the same manner as in Example 42 except that 5% was used in combination.
- Table 8 shows the whiteness, K value, HexA content, and viscosity of the bleached pulp.
- a bleached pulp was obtained in the same manner as in Example 43 except that 5% was used in combination.
- Table 8 shows the whiteness, K value, HexA content, and viscosity of the bleached pulp.
- Example 20 the same procedure as in Example 20 was performed except that 0.1% each of the mixture of oxalic acid and EDTA shown in Table 9 below was used in combination with peroxomonosulfuric acid. Obtained. Table 9 shows the whiteness, K value, HexA content, and viscosity of the bleached pulp. [0130] [Table 9]
- Example 20 the treatment temperature during peroxomonosulfuric acid treatment was 40 ° C and 50 ° C, respectively.
- a bleached pulp was obtained in the same manner as in Example 20, except that the temperature was 60 ° C. and the treatment times were 5 hours, 4 hours, and 2.5 hours, respectively.
- Table 10 shows the whiteness, K value, HexA content, and viscosity of the bleached pulp.
- Example 20 caustic soda was 1.0%, 1.30%, 1.60%, 1.70%, 1.78%, 1.85%, 1.90%, 2.06%, 2. 13% added, peroxomonosulfuric acid treatment pH was carried out in the same manner as in Example 20 except that it was adjusted as shown in Table 11 to obtain bleached pulp.
- Table 11 shows the whiteness, K value, HexA content, and viscosity of the bleaching norp.
- Examples 66 to 68 caustic soda was added at 1.86%, 1.78%, and 1.72%, respectively, and the peroxomonosulfuric acid treatment pH was adjusted as shown in Table 12, and the same as in Examples 66 to 68 And bleached pulp was obtained.
- Table 12 shows the K value, HexA content, and viscosity of the bleached pulp.
- the treatment temperature was adjusted to the range of 40-60 ° C, and the treatment pH was adjusted to the range of 3-4.
- the range By adjusting the range, the decrease in the viscosity of the pulp could be suppressed while maintaining the HexA removal effect.
- the bleached pulp production method of the present invention comprises a step of treating with peroxosulfuric acid that can be produced from an inexpensive raw material by an inexpensive method before or after the chlorine-free bleaching step, or after the complete chlorine-free bleaching step! Therefore, it is possible to economically produce white pulp from which HexA has been efficiently removed.
- the bleached pulp to acidic papermaking, the fading property of the bleached pulp of acidic paper can be improved.
Abstract
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US12/301,130 US8268123B2 (en) | 2006-05-17 | 2007-05-15 | Process for producing bleached pulp |
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BRPI0711822A BRPI0711822B1 (pt) | 2006-05-17 | 2007-05-15 | processo para produção de pasta branqueada |
CA2652325A CA2652325C (en) | 2006-05-17 | 2007-05-15 | Process for producing bleached pulp |
EP07743365A EP2022887B1 (en) | 2006-05-17 | 2007-05-15 | Process for producing bleached pulp |
ZA2008/09453A ZA200809453B (en) | 2006-05-17 | 2008-11-05 | Process for producing bleached pulp |
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WO2009081714A1 (ja) | 2007-12-20 | 2009-07-02 | Mitsubishi Gas Chemical Company, Inc. | 漂白パルプの製造方法 |
WO2015037424A1 (ja) * | 2013-09-12 | 2015-03-19 | 三菱瓦斯化学株式会社 | セルロースの製造方法 |
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JP5515409B2 (ja) * | 2009-05-15 | 2014-06-11 | 三菱瓦斯化学株式会社 | Ecf漂白パルプの製造方法 |
JP5526604B2 (ja) * | 2009-05-21 | 2014-06-18 | 三菱瓦斯化学株式会社 | Ecf漂白方法 |
JP2011001636A (ja) * | 2009-06-16 | 2011-01-06 | Mitsubishi Gas Chemical Co Inc | 漂白パルプの製造方法 |
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JP2009138293A (ja) * | 2007-12-05 | 2009-06-25 | Daio Paper Corp | 漂白アルカリ化学パルプの製造方法 |
WO2009081714A1 (ja) | 2007-12-20 | 2009-07-02 | Mitsubishi Gas Chemical Company, Inc. | 漂白パルプの製造方法 |
CN105672018B (zh) * | 2007-12-20 | 2018-09-11 | 三菱瓦斯化学株式会社 | 漂白纸浆的制造方法 |
WO2015037424A1 (ja) * | 2013-09-12 | 2015-03-19 | 三菱瓦斯化学株式会社 | セルロースの製造方法 |
US20210062419A1 (en) * | 2019-08-27 | 2021-03-04 | Qilu University Of Technology | Method For Preparing Dissolving Pulp By Totally Chlorine-Free Bleaching Of Poplar Kraft Pulp |
Also Published As
Publication number | Publication date |
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BRPI0711822A2 (pt) | 2012-01-17 |
US20130062026A1 (en) | 2013-03-14 |
US8864942B2 (en) | 2014-10-21 |
CN101443514A (zh) | 2009-05-27 |
CA2652325A1 (en) | 2007-11-22 |
JP2007308824A (ja) | 2007-11-29 |
EP2022887A4 (en) | 2010-09-15 |
US8268123B2 (en) | 2012-09-18 |
CA2652325C (en) | 2015-06-30 |
BRPI0711822B1 (pt) | 2018-09-25 |
JP4967451B2 (ja) | 2012-07-04 |
ZA200809453B (en) | 2010-02-24 |
CN101443514B (zh) | 2012-11-28 |
EP2022887B1 (en) | 2012-04-18 |
US20090183845A1 (en) | 2009-07-23 |
CN102704305B (zh) | 2014-09-17 |
CN102704305A (zh) | 2012-10-03 |
EP2022887A1 (en) | 2009-02-11 |
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