Alkali cellulose, preparation method thereof, used device and viscose fiber

Abstract

The invention belongs to the technical field of artificial fibers, and particularly relates to alkali cellulose, a preparation method thereof, a used device and a viscose fiber. Pulp raw materials are soaked in alkali liquor to obtain alkalized pulp porridge, the pulp raw materials comprise chemical fiber pulp and / or papermaking pulp, and the soaking temperature is smaller than or equal to 60 DEG C; the alkalized pulp porridge and a hydrogen peroxide solution are mixed for oxidative degradation, oxidized pulp porridge is obtained, the oxidative degradation time is longer than or equal to 1 h, and oxidative degradation is carried out under the conditions of normal temperature and normal pressure; and carrying out solid-liquid separation on the oxidized slurry porridge to obtain the alkali cellulose. The alkali cellulose with the performance reaching the standard and stability can be produced, and finally the viscose fibers meeting the requirements are produced. The method realizes direct production of the viscose fibers from the papermaking pulp. Meanwhile, the preparation method provided by the invention is mild in operation condition, simple in reaction step and suitable for industrial application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of artificial fibers, and particularly relates to alkali cellulose, a preparation method and device thereof, and viscose fiber. BACKGROUND

[0002] Viscose fiber, also known as viscose filament, is a kind of artificial fiber. At present, the existing process route of viscose fiber factories is as follows: pulp raw material - immersion - squeezing - crushing - aging - cooling - air conveying - weighing - yellowing - filtering - defoaming - spinning. The raw material used by viscose fiber is a special raw material (hereinafter referred to as chemical fiber pulp) specially used for viscose fiber production. The indexes of the chemical fiber pulp need to meet FZ / T51001-2009. According to the standard, the content of alpha cellulose (alpha-cellulose, referred to as alpha cellulose) in the chemical fiber pulp needs to be at least 89% or above, among which the minimum alpha cellulose content of cotton pulp for viscose filament is required to be 95% or above. The main component of the chemical fiber pulp is alpha cellulose, containing a small amount of hemicellulose (cellulose with a polymerization degree of less than 200), and the contents of polyglucose, resin, lignin, ash and iron are very low. The characteristics of the chemical fiber pulp are high purity of alpha cellulose, less impurities, moderate polymerization degree and small distribution range, good reaction performance and good filtering performance.

[0003] In the prior art, the chemical fiber pulp is immersed in a sodium hydroxide aqueous solution with a concentration of about 18%, so that the cellulose is converted into alkali cellulose, the hemicellulose in the pulp is dissolved out, and the polymerization degree is partially reduced. The excess alkali solution is removed by squeezing, and the blocky alkali cellulose is crushed into loose flocculent bodies on a crusher, so that the uniformity of the subsequent yellowing reaction is improved due to the increase in the surface area.

[0004] At present, the preparation of alkali cellulose in the production process of viscose fiber not only has high raw material cost, but also has high control difficulty, incomplete conversion of alkali cellulose or excessive depolymerization, etc. These problems result in poor production stability of alkali cellulose and ultimately affect the quality of viscose fiber. SUMMARY

[0005] The purpose of the present application is to provide alkali cellulose, a preparation method and device thereof, and viscose fiber. The preparation method provided by the present application expands the source of raw materials of viscose fiber, reduces the preparation cost of alkali cellulose, can produce alkali cellulose with stable performance and up to standard, and ultimately produces viscose fiber meeting the requirements. At the same time, the preparation method provided by the present application has mild operating conditions and is suitable for industrial application.

[0006] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] The present application provides a preparation method of alkali cellulose, comprising the following steps:

[0008] The pulp raw material is immersed in an alkali solution to obtain an alkaliized pulp, the pulp raw material comprises chemical fiber pulp and / or papermaking pulp, the alkali solution is an aqueous solution of alkali metal hydroxide, the mass content of alkali metal hydroxide in the alkali solution is greater than or equal to 18%, and the temperature of the immersion is less than or equal to 60 DEG C.

[0009] The alkaliized pulp is mixed with a hydrogen peroxide solution to obtain an oxidized pulp, the mass content of H2O2 in the hydrogen peroxide solution is greater than or equal to 20%, the mass ratio of the hydrogen peroxide solution to the pulp raw material is 0.3-6%, the time of the oxidative degradation is greater than or equal to 1 h, and the oxidative degradation is carried out at normal temperature and pressure.

[0010] The oxidized pulp is subjected to solid-liquid separation to obtain alkali cellulose.

[0011] Preferably, the mass content of alkali metal hydroxide in the alkali solution is 18-25%, and the alkali metal hydroxide is NaOH.

[0012] Preferably, the temperature of the immersion is 40-60 DEG C, and the time is 20-60 min.

[0013] Preferably, the mass content of H2O2 in the hydrogen peroxide solution is 20-30%.

[0014] Preferably, the time of the oxidative degradation is 1-2 h.

[0015] Preferably, when the pulp raw material is chemical fiber pulp, the mass ratio of the hydrogen peroxide solution to the chemical fiber pulp is 0.3-1.5%.

[0016] When the pulp raw material is papermaking pulp, the mass ratio of the hydrogen peroxide solution to the papermaking pulp is 3-6%.

[0017] Preferably, the solid-liquid separation is pressing, and the pressure of the pressing tank is 0.02-0.08 MPa.

[0018] The application provides alkali cellulose prepared by the preparation method.

[0019] The application provides a device for preparing alkali cellulose, which comprises an immersion barrel, a mixer, a hydrogen peroxide storage tank, an oxygenolysis barrel and a press.

[0020] The application provides viscose fiber, and the preparation raw material of the viscose fiber is the alkali cellulose.

[0021] The application provides a preparation method of alkali cellulose, comprising the following steps: immersing pulp raw materials in an alkali liquor to obtain alkaliized pulp, wherein the pulp raw materials comprise chemical pulp and / or papermaking pulp, the alkali liquor is an aqueous solution of alkali metal hydroxide, the mass content of alkali metal hydroxide in the alkali liquor is greater than or equal to 18%, and the temperature of the immersion is less than or equal to 60 DEG C; mixing the alkaliized pulp and a hydrogen peroxide solution to perform oxidative degradation, so as to obtain oxidized pulp, wherein the mass content of H2O2 in the hydrogen peroxide solution is greater than or equal to 20%, the mass ratio of the hydrogen peroxide solution to the pulp raw materials is 0.3-6%, the time of the oxidative degradation is greater than or equal to 1 h, and the oxidative degradation is performed under normal temperature and pressure; and performing solid-liquid separation on the oxidized pulp to obtain alkali cellulose. The pulp raw materials are treated by the method of medium-temperature immersion-normal temperature and pressure oxidative degradation, so that the source of viscose fiber raw materials is expanded. In the process of the oxidative degradation, the alkaliized pulp is treated by the hydrogen peroxide solution, so that the alkaliized pulp is subjected to oxidative degradation; in the process of the oxidative degradation, the mass content of H2O2 in the hydrogen peroxide solution, the mass ratio of the hydrogen peroxide solution to the pulp raw materials and the time of the oxidative degradation of the alkaliized pulp are optimized, so that excessive degradation is avoided, the papermaking pulp plant cell wall is damaged in a high-oxygen and high-alkali environment, the fiber polymerization degree is reduced, the cellulose characteristics are changed, the semi-cellulose and the poly-pentose are dissolved, and the reaction performance of the pulp is improved. The copper ammonia viscosity of the alkali cellulose in the obtained oxidized pulp is about 50 mPa s. Then, the oxidized pulp is subjected to solid-liquid separation to obtain alkali cellulose. The preparation method provided by the application can produce alkali cellulose with stable performance and up to standard, and finally produce viscose fiber meeting the requirements. The application realizes the direct production of viscose fiber from papermaking pulp, and the produced viscose fiber product meets the product quality requirements of the national standard GB / T 14463-2008 Viscose Staple Fiber.

[0022] Meanwhile, the preparation method provided by the application has mild operation conditions, simple reaction steps and is suitable for industrial application.

[0023] The application provides a device for preparing alkali cellulose. The device provided by the application has good treatment effect, high production capacity, small occupied area, low energy consumption and low maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The application provides a device for preparing alkali cellulose. The device provided by the application has good treatment effect, high production capacity, small occupied area, low energy consumption and low maintenance cost.

[0025] In the figure, 1 is an immersion barrel, 2 is a hydrogen peroxide storage tank, 3 is an oxygenolysis barrel, 4 is a press, 5 is a first material conveying pipeline, 6 is a hydrogen peroxide pipeline, 7 is a second material conveying pipeline, 8 is a stirrer, 9 is a conveying pump and 10 is a mixer. DETAILED DESCRIPTION

[0026] The present application provides a method for preparing alkali cellulose, comprising the following steps:

[0027] immersing pulp raw material in alkali liquor to obtain alkaliized pulp, wherein the pulp raw material comprises chemical pulp and / or papermaking pulp, the alkali liquor is aqueous alkali metal hydroxide solution, the mass content of alkali metal hydroxide in the alkali liquor is ≥18%, and the temperature of the immersing is ≤60℃;

[0028] mixing the alkaliized pulp with hydrogen peroxide solution to obtain oxidized pulp, wherein the mass content of H2O2 in the hydrogen peroxide solution is ≥20%, the time of the oxidized degradation is ≥1h, the mass ratio of the hydrogen peroxide solution to the pulp raw material is 0.3-6%, and the oxidized degradation is carried out under normal temperature and pressure;

[0029] solid-liquid separating the oxidized pulp to obtain alkali cellulose.

[0030] In the present application, all the raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified. The percentages in the present application are mass percentages, unless otherwise specified. The solutions in the present application are aqueous solutions, unless otherwise specified. The normal temperature and room temperature in the present application generally refer to the temperature of 15-25℃, and are generally defined as 25℃.

[0031] In the present application, pulp raw material is immersed in alkali liquor to obtain alkaliized pulp, wherein the pulp raw material comprises chemical pulp and / or papermaking pulp, the alkali liquor is aqueous alkali metal hydroxide solution, the mass content of alkali metal hydroxide in the alkali liquor is ≥18%, and the temperature of the immersing is ≤60℃. In the present application, the mass content of alkali metal hydroxide in the alkali liquor is preferably 18-25%, and the alkali metal hydroxide is preferably NaOH. In the present application, the temperature of the immersing is preferably 40-60℃, and can be 50℃ or 52℃ in the examples. The time of the immersing is preferably 20-60min, and can be 28min or 32min in the examples.

[0032] After obtaining the alkalized pulp slurry, the alkalized pulp slurry is mixed with a hydrogen peroxide solution to perform oxidative degradation, so as to obtain an oxidized pulp slurry, the hydrogen peroxide solution contains H2O2 with a mass content of ≥20%, the mass ratio of the hydrogen peroxide solution to the pulp slurry raw material is 0.3-6%, the oxidative degradation is performed for ≥1 h, and the oxidative degradation is performed under normal temperature and pressure.

[0033] In the present application, the oxidative degradation is preferably performed for 1-2 h, and in the examples, it can be performed for 1 h or 1.25 h.

[0034] After obtaining the oxidized pulp slurry, the oxidized pulp slurry is subjected to solid-liquid separation, so as to obtain alkali cellulose. In the present application, the solid-liquid separation is pressing. The solid-liquid separation is preferably performed in a press, and the pressure of the pulp tank of the press (i.e., the press) is preferably 0.02-0.08 MPa, and in the examples, it can be 0.045 MPa or 0.05 MPa.

[0035] At present, the chemical fiber pulp used in the production of viscose fibers not only has high production cost, but also is in short supply. The papermaking pulp is limited by the existing viscose fiber production process and control conditions, and many indexes cannot meet the requirements of the existing viscose fiber production process, and therefore cannot be directly applied to the production of viscose fibers. The content of cellulose A in the papermaking pulp is generally 82%-91%, which is 4%-7% lower than that in the chemical fiber pulp. The contents of hemicellulose, resin, polyglucose and ash are relatively high, which far exceed the use standard of the chemical fiber pulp in the existing viscose fiber production process. In addition, the papermaking pulp has high degree of polymerization and is not easy to depolymerize. According to the existing viscose fiber production process, after the papermaking pulp is directly added to the lye for impregnation, the generated alkali cellulose cannot fully react with carbon disulfide, and a large amount of impurities causes the increase of the side reaction of carbon disulfide, which cannot meet the current viscose production process. The method of medium-temperature impregnation-normal temperature and pressure oxidative degradation adopted in the present application can ensure that the papermaking pulp is destroyed in a high-oxygen and high-alkali environment, reduce the degree of polymerization of the fiber, change the characteristics of the cellulose, dissolve the hemicellulose and polyglucose, and improve the reaction performance of the pulp.

[0036] The present application provides the alkali cellulose prepared by the preparation method.

[0037] The present invention provides an apparatus for preparing alkali cellulose, comprising an impregnation barrel, a mixer, a hydrogen peroxide storage tank, an oxygen decomposition barrel, and a press; the impregnation barrel is connected to the mixer via a first material delivery pipeline, the hydrogen peroxide storage tank is connected to the mixer via a hydrogen peroxide pipeline, the mixer is connected to the oxygen decomposition barrel via a third material delivery pipeline, and the oxygen decomposition barrel is connected to the press via a second material delivery pipeline.

[0038] In the present invention, the impregnation vat is used to immerse the pulp raw material in alkali solution. The mixer is used to mix the alkalized pulp porridge with the hydrogen peroxide solution. The oxygen decomposition vat is used to oxidatively degrade the alkalized pulp porridge after mixing with the hydrogen peroxide solution. The press is used to perform solid-liquid separation on the oxidized pulp porridge. The hydrogen peroxide storage tank is used to store the hydrogen peroxide solution.

[0039] In the present invention, the oxygen decomposition tank is preferably a normal temperature and pressure oxygen decomposition tank. The first feed line preferably connects the discharge end of the impregnation tank with the feed end at the bottom of the oxygen decomposition tank. The second feed line preferably connects the discharge end at the top of the oxygen decomposition tank with the feed end of the press.

[0040] In the present invention, the hydrogen peroxide pipeline is preferably provided with a delivery pump. The oxygen decomposition tank is preferably provided with a stirrer, which is arranged at the bottom of the oxygen decomposition tank.

[0041] The present invention provides a viscose fiber, wherein the raw material for preparing the viscose fiber is the alkali cellulose described in the above technical solution.

[0042] In the present invention, the viscose fiber is preferably obtained by sequentially pulverizing, cooling, air-feeding, weighing, xanthening, grinding and dissolving, filtering, degassing, and spinning the alkali cellulose.

[0043] The present invention has no special requirements on the specific implementation of the pulverization.

[0044] In the present invention, the cooling is preferably carried out in an alkali fiber cooling system, and the temperature of the alkali cellulose after the cooling is preferably 26-28°C.

[0045] In the present invention, the yellowing temperature is preferably ≤34°C.

[0046] In the present invention, the filtration preferably includes: first filtering through a 25 μm KK filter, and then filtering through a second 20 μm KK filter.

[0047] In the present invention, the temperature change during the degassing process is preferably less than 10°C, and the temperature of the degassing outlet is preferably 20°C.

[0048] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0049] The various chemical reagents and chemical supplies mentioned in the following examples are all common chemical reagents and chemical supplies known in the prior art unless otherwise specified; the following are the equipment and devices used in the private sector, and are all common equipment and devices known in the art unless otherwise specified. The base cellulose used in the following examples is Figure 1 The device shown in the structure is prepared.

[0050] Example 1

[0051] The present embodiment provides a method for preparing base cellulose, which is carried out in the following steps:

[0052] Firstly, the pulp raw material (chemical fiber pulp) is transported to the impregnation barrel 1 and impregnated in the NaOH aqueous solution with a mass content of 18% NaOH, the impregnation temperature is controlled at 40°C, the impregnation time is 20 min, and the chemical fiber pulp and the NaOH aqueous solution are subjected to alkalization reaction to obtain alkalized pulp;

[0053] Secondly, the alkalized pulp is mixed with hydrogen peroxide aqueous solution (H2O2 content is 20%) and transported to the oxygenolysis barrel 3 at normal temperature and pressure, and subjected to oxidative degradation under normal temperature and pressure, wherein the mass ratio of hydrogen peroxide aqueous solution to chemical fiber pulp is 0.3%, and the oxidative degradation time is 1 h, to obtain oxidized pulp;

[0054] Thirdly, the oxidized pulp obtained in the second step is sent to the press 4, and the pulp tank pressure of the press 4 is 0.02 MPa, and the base cellulose is obtained after pressing.

[0055] The present embodiment provides a method for preparing viscose fiber, which is carried out in the following steps:

[0056] After the base cellulose is crushed, its specific gravity needs to be controlled at ≤130 g / L, and then it is subjected to aging treatment in the aging drum for 4 hours to ensure that the outlet copper ammonia viscosity is not less than 45 mPa·s. Then, the base cellulose is subjected to temperature reduction and dehumidification in the base cellulose cooling system to reduce its temperature to 26-28°C, and then it is sent to the stock bin through the air conveying system for weighing and metering.

[0057] The yellowing reaction was carried out in batches according to the design capacity of the yellowing machine, and the final temperature of the yellowing was controlled to be less than or equal to 34°C. After the yellowing was completed, the material was ground and dissolved to ensure that the post-dissolution mesh value was greater than or equal to 90 mL, and then the material was subjected to mixing treatment. The mixed material was first filtered through a 25 μm KK filter, then filtered through a 20 μm KK filter, and then entered a defoaming system. During the defoaming process, the temperature difference was controlled to be 4-10°C, and the outlet temperature of the defoaming was maintained at 20°C. Finally, the material was filtered through three 15 μm KK filters and sent to the spinning section to obtain viscose fibers.

[0058] Example 2

[0059] The difference between this example and Example 1 is that the pulp raw material is papermaking pulp, the mass ratio of the aqueous hydrogen peroxide solution to the papermaking pulp is 3%, and the remaining steps are the same as those of Example 1.

[0060] Example 3

[0061] The difference between this example and Example 1 is that the immersion temperature is 60°C and the immersion time is 1 h, and the remaining steps are the same as those of Example 1.

[0062] Example 4

[0063] The difference between this example and Example 1 is that the mass ratio of the aqueous hydrogen peroxide solution to the chemical pulp is 1.5%, and the remaining steps are the same as those of Example 1.

[0064] Example 5

[0065] The difference between this example and Example 1 is that the oxidation degradation time is 2 h, and the remaining steps are the same as those of Example 1.

[0066] Example 6

[0067] The difference between this example and Example 1 is that the content of H2O2 in the aqueous hydrogen peroxide solution is 30%, and the remaining steps are the same as those of Example 1.

[0068] Example 7

[0069] The difference between this example and Example 2 is that the mass ratio of the aqueous hydrogen peroxide solution to the papermaking pulp is 6%, and the remaining steps are the same as those of Example 2.

[0070] Example 8

[0071] The difference between this example and Example 2 is that the immersion temperature is 60°C and the immersion time is 1 h, and the remaining steps are the same as those of Example 2.

[0072] Example 9

[0073] The difference between this example and Example 1 is that the pressure of the press 4 is 0.08 MPa, and the remaining steps are the same as those of Example 1.

[0074] Example 10

[0075] The difference between this example and Example 2 is that the oxidation degradation time is 2 h, and the remaining steps are the same as those of Example 2.

[0076] Example 11

[0077] This example provides a method for preparing alkali cellulose, which is carried out according to the following steps:

[0078] In the first step, 1030 kg of chemical pulp is transported into the impregnation barrel 1, 22.3 m 3 of 22.2% sodium hydroxide aqueous solution is added, and impregnation is carried out at a temperature of 50°C for 28 min to obtain alkaliized pulp; in the second step, the alkaliized pulp is transported into the oxygenolysis barrel 3, and 12 kg of hydrogen peroxide aqueous solution with a mass content of 27.6% is injected through the hydrogen peroxide pipeline 6, and the reaction time is 1.0 h, and the oxidized pulp is obtained after sufficient oxidation degradation; in the third step, the oxidized pulp obtained in the second step is sent into the press 4, and the alkali cellulose is obtained after pressing under a pulp tank pressure of 0.045 MPa.

[0079] The obtained alkali cellulose is subjected to crushing, cooling, air feeding, weighing, yellowing, filtering, defoaming, and spinning in sequence, and finally viscose fiber is obtained. The obtained viscose fiber is subjected to testing of relevant indexes of GB / T 14463-2008 Viscose Staple Fiber National Standard, and the testing results are shown in Table 1. As can be seen from Table 1, the viscose fiber produced in this example meets the requirements of the cotton type superior product in GB / T 14463-2008 Viscose Staple Fiber.

[0080] Example 12

[0081] This example provides a method for preparing alkali cellulose, which is carried out according to the following steps:

[0082] In the first step, 1000 kg of papermaking pulp is transported into the impregnation barrel 1, 23.2 m 3 of 23.8% sodium hydroxide aqueous solution is added, and impregnation is carried out at a temperature of 52°C for 32 min to obtain alkaliized pulp; in the second step, the alkaliized pulp is transported into the oxygenolysis barrel 3, and 55 kg of hydrogen peroxide aqueous solution with a mass content of 27.8% is injected through the hydrogen peroxide pipeline 6, and the reaction time is 1.25 h, and the oxidized pulp is obtained after sufficient oxidation degradation; in the third step, the oxidized pulp obtained in the second step is sent into the press 4, and the alkali cellulose is obtained after pressing under a pulp tank pressure of 0.050 MPa.

[0083] The obtained alkali cellulose is subjected to crushing, cooling, air conveying, weighing, yellowing, filtering, defoaming and spinning in sequence, and finally viscose fiber is obtained. The obtained viscose fiber is subjected to GB / T 14463-2008 viscose staple fiber national standard related index test, and the test results are shown in Table 1. As shown in Table 1, the viscose fiber produced in this embodiment meets the requirements of GB / T 14463-2008 viscose staple fiber cotton type superior product.

[0084] Table 1: Test results of viscose fiber produced in Example 11 and Example 12

[0085] Quality index of viscose fiber reached Viscose pulp of Example 11 Viscose pulp of Example 12 Specification 1.33 dtex x 38 mm fiber 1.33 dtex x 38 mm fiber Dry breaking strength (cN / dtex) 2.52 2.34 Wet breaking strength (cN / dtex) 1.33 1.22 Dry breaking elongation (%) 21.1 19.1 Linear density deviation rate (%) -0.75 -2.26 Residual sulfur content (mg / 100g) 5.6 5.8 Defects (mg / 100g) 0.0 0.4 Coefficient of variation (CV) of dry breaking strength (%) 9.4 9.7 Whiteness (%) 83.7 83.5 Moisture regain (%) 10.8 12.3 Oil content (%) 0.30 0.28 Coarse and parallel yarns (mg / 100g) 0.0 0.1 Lumps (mg / 100g) 0.0 0.3 Linear density (dtex): 1.32 1.30 Length (mm) 38.9 39.2

[0086] As shown in Table 1, the method of this application uses medium-temperature impregnation-constant-temperature and constant-pressure oxidative degradation to treat pulp raw materials, which can realize the oxidative degradation of chemical fiber pulp and papermaking pulp. The method provided by the application uses oxygenolysis barrel 3 to extend the oxidative degradation time of the pulp raw material in the alkali solution. In a high-oxygen and high-alkali environment, the paper pulp plant cell wall is destroyed, the fiber polymerization degree is reduced, the cellulose characteristics are changed, the semi-fiber and pentosan are dissolved, the reaction performance of the pulp is improved, the alkali cellulose with stable performance is produced, and finally the viscose fiber meeting the requirements is produced. The application realizes the direct production of viscose fiber from papermaking pulp, and the produced viscose fiber product meets the product quality requirements of GB / T 14463-2008 viscose staple fiber.

[0087] Table 2 is the comparison results of the oxidative degradation method provided by the application with the aging box process and the aging drum process.

[0088] Table 2 is the comparison results of the oxidative degradation method provided by the application with the aging box process and the aging drum process.

[0089] Item Oxidative degradation process Aging drum process Aging box process Consistency of degree of depolymerization High Medium Low Duration of degree of depolymerization 1 to 2 h 3 to 5 h 3 to 5 h Adjustment means for degree of depolymerization Accurate addition of hydrogen peroxide Aging time and air temperature adjustment Aging time and air temperature adjustment Electricity consumption 55 kW 104 kW 15 kW Maintenance Simple Complex Simple Floor space 30㎡ 120㎡ 80㎡

[0090] As shown in Table 2, the oxidative degradation process used in the application can shorten the preparation time of alkali cellulose by more than 3h during the production of viscose staple fiber. In addition, the device used to prepare alkali cellulose has the characteristics of small floor area, low energy consumption and low maintenance cost. In actual production, the preparation method and device of alkali cellulose provided by the application can remove the existing aging system, or the obtained alkali cellulose can be further subjected to crushing and subsequent processes such as aging and cooling.

[0091] In summary, the application uses the method of impregnation-oxidative degradation to realize the oxidative degradation of chemical fiber pulp and papermaking pulp, which expands the source of viscose fiber raw materials. The device used to prepare alkali cellulose provided by the application has good treatment effect, small floor area, low energy consumption and low maintenance cost.

[0092] Although the above embodiments have been described in detail, it should be understood that these are only some embodiments of the present application, but not all embodiments, and other embodiments can be obtained without creativity on the basis of the above embodiments, and these embodiments all belong to the protection scope of the present application.

Claims

1. A method for preparing alkali cellulose, characterized in that: The following steps are involved: The pulp raw material is immersed in an alkaline solution to obtain an alkaline pulp porridge, wherein the pulp raw material includes chemical fiber pulp and / or paper pulp, the alkaline solution is an alkali metal hydroxide aqueous solution, the mass content of the alkali metal hydroxide in the alkaline solution is ≥18%, and the immersion temperature is ≤60°C; The alkalized pulp porridge and hydrogen peroxide solution are mixed for oxidative degradation to obtain oxidized pulp porridge, wherein the mass content of H2O2 in the hydrogen peroxide solution is ≥20%, the mass ratio of the hydrogen peroxide solution to the pulp raw material is 0.3-6%, the oxidative degradation time is ≥1h, and the oxidative degradation is carried out at normal temperature and pressure; The oxidized pulp porridge is separated into solid and liquid to obtain alkali cellulose.

2. The preparation method according to claim 1, characterized in that The mass content of the alkali metal hydroxide in the alkali solution is 18-25%, and the alkali metal hydroxide is NaOH.

3. The preparation method according to claim 1 or 2, characterized in that The immersion temperature is 40-60° C., and the immersion time is 20-60 minutes.

4. The preparation method according to claim 1, characterized in that The mass content of H2O2 in the hydrogen peroxide solution is 20-30%.

5. The preparation method according to claim 1 or 4, characterized in that The oxidative degradation time is 1 to 2 hours.

6. The preparation method according to claim 1 or 4, characterized in that When the pulp raw material is chemical fiber pulp, the mass ratio of the hydrogen peroxide solution to the chemical fiber pulp is 0.3-1.5%; When the pulp raw material is papermaking pulp, the mass ratio of the hydrogen peroxide solution to the papermaking pulp is 3-6%.

7. The preparation method according to claim 1, characterized in that The solid-liquid separation is performed by pressing, and the slurry tank pressure of the pressing is 0.02 to 0.08 MPa.

8. Alkali cellulose prepared by the preparation method according to any one of claims 1 to 7.

9. A device for preparing alkali cellulose, characterized in that: The invention comprises an impregnation barrel, a mixer, a hydrogen peroxide storage tank, an oxygen decomposition barrel and a press; the impregnation barrel is connected to the mixer via a first feed line, the hydrogen peroxide storage tank is connected to the mixer via a hydrogen peroxide pipeline, the mixer is connected to the oxygen decomposition barrel via a third feed line, and the oxygen decomposition barrel is connected to the press via a second feed line.

10. A viscose fiber, characterized in that: The raw material for preparing the viscose fiber is the alkali cellulose described in claim 8.

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