A colorimetric full-process detection method for a lyocell fiber production system

Abstract

The present application relates to lyocell fiber production technical field, especially lyocell fiber production system's chroma whole process detection method, including the following steps: S1) component A is stirred with deionized water mixing, take the supernatant after mixing and detect N-methyl morpholine-N-oxide mass concentration, is recorded as c;The component A is porridge or glue liquid;S2) with N-methyl morpholine-N-oxide mass concentration in spinning bath ± 0.5% as center value range, when the c is in the center value range, stationary, the supernatant after stationary is centrifuged, and the supernatant after centrifugation is detected chroma;When the c is not in the center value range, continue to add A or deionized water until the value of c is in the center value range, stationary, the supernatant after stationary is centrifuged, and the supernatant after centrifugation is detected chroma.The present application can establish whole process chroma detection (from porridge to spinning bath) by this method, which can better guide production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lyocell fiber production, and particularly relates to a colorimetric full-process detection method for a lyocell fiber production system. BACKGROUND

[0002] Lyocell dope refers to a spinning dope formed by dissolving cellulose in N-methyl morpholine-N-oxide (NMMO) aqueous solution in the process of producing lyocell fiber.

[0003] At present, the safety evaluation methods for the lyocell fiber production system mainly include by-product detection and solvent colorimetric detection. It is found in the production process that the safety of the system decreases and the probability of thermal decomposition of the dope increases when the colorimetric value of the system, especially the colorimetric value of the lyocell dope, increases.

[0004] The existing colorimetric detection mainly uses an ultraviolet spectrophotometer. This instrument can only detect the colorimetric value of the solvent and cannot detect the colorimetric value of the pulp or the dope. However, the pulp or the dope is involved in the lyocell fiber production system, so the ultraviolet spectrophotometer cannot be used for detection. SUMMARY

[0005] Therefore, the present application aims to solve the technical problem by providing a colorimetric full-process detection method for a lyocell fiber production system. This method can establish full-process colorimetric detection (from the pulp to the spinning bath) and better guide the production.

[0006] The present application provides a colorimetric full-process detection method for a lyocell fiber production system, which comprises the following steps:

[0007] S1) stirring and mixing component A with deionized water, detecting the mass concentration of N-methyl morpholine-N-oxide in the supernatant after mixing, and denoting it as c; the component A is pulp or dope;

[0008] S2) taking the mass concentration of N-methyl morpholine-N-oxide in the spinning bath as the center value range ± 0.5%, when the c is within the center value range, standing, centrifuging the supernatant after standing, and detecting the colorimetric value of the supernatant after centrifugation; when the c is not within the center value range, continuously adding A or deionized water until the value of the c is within the center value range, standing, centrifuging the supernatant after standing, and detecting the colorimetric value of the supernatant after centrifugation.

[0009] Preferably, the pulp or the dope contains cellulose, NMMO and water.

[0010] Preferably, in the pulp or the dope, the mass content of cellulose is 9% to 14%, and the mass content of NMMO is 54% to 90%.

[0011] Preferably, the mass ratio of the component A to deionized water is 1:2-100.

[0012] Preferably, the temperature of the stirring mixing is 55-65℃.

[0013] Preferably, the time of the stirring mixing is 3-7 min.

[0014] Preferably, the time of the standing is 8-12 min.

[0015] Preferably, the rotating speed of the centrifugation is above 400 rpm.

[0016] Preferably, the rotating speed of the centrifugation is 800-1200 rpm.

[0017] Preferably, the time of the centrifugation is 2-3 min.

[0018] The present application provides a kind of lyocell fiber production system's colorimetric full process detection method, comprising the following steps: S1) component A is stirred and mixed with deionized water, the mass concentration of N-methyl morpholine-N-oxide in the supernatant after mixing is detected, and is recorded as c;The component A is porridge or glue liquid;S2) with the mass concentration of N-methyl morpholine-N-oxide in spinning bath ± 0.5% as center value range, when the c is in the center value range, standing, the supernatant after standing is centrifuged, and the supernatant after centrifugation is detected colorimetrically;When the c is not in the center value range, continue to add A or deionized water until the value of the c is in the center value range, standing, the supernatant after standing is centrifuged, and the supernatant after centrifugation is detected colorimetrically.The present application can establish full process colorimetric detection (from porridge to spinning bath) by this method, and can better guide production. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] The present application provides a kind of lyocell fiber production system's colorimetric full process detection method, comprising the following steps:

[0021] S1) component A is stirred and mixed with deionized water, the mass concentration of N-methyl morpholine-N-oxide (abbreviated as NMMO) in the supernatant after mixing is detected, and is recorded as c;The component A is porridge or glue liquid;

[0022] S2) taking the mass concentration of N-methylmorpholine-N-oxide in the spinning bath as a center value range of ±0.5%, when the c is in the center value range, standing, centrifuging the supernatant after standing, and taking the centrifuged supernatant to detect the color; when the c is not in the center value range, continuing to add A or deionized water until the value of the c is in the center value range, standing, centrifuging the supernatant after standing, and taking the centrifuged supernatant to detect the color.

[0023] Regarding step S1):

[0024] Mixing component A with deionized water by stirring, taking the mass concentration of N-methylmorpholine-N-oxide (NMMO for short) in the mixed supernatant, denoted as c; the component A is pulp or glue solution.

[0025] In the present application, the mass concentration is the mass percentage content.

[0026] In the present application, component A is mixed with deionized water by stirring to soak out NMMO in the pulp or glue solution.

[0027] In some embodiments of the present application, the pulp or glue solution is composed of three substances, including cellulose, NMMO and water. In the pulp or glue solution, the mass content of cellulose is 9% to 14%, such as 10.5%, 12%; the mass content of NMMO is 54% to 90%, such as 64%, 73%.

[0028] In some embodiments of the present application, the mass ratio of component A to deionized water is 1:2 to 100, such as 1:2 to 20 or 1:2 to 10, specifically 1:2 or 1:8.

[0029] In some embodiments of the present application, the temperature of the stirring and mixing is 55 to 65℃, such as 60℃; the time is 3 to 7 min, such as 5 min.

[0030] Regarding step S2):

[0031] Taking the mass concentration of N-methylmorpholine-N-oxide in the spinning bath as a center value range of ±0.5%, when the c is in the center value range, standing, centrifuging the supernatant after standing, and taking the centrifuged supernatant to detect the color; when the c is not in the center value range, continuing to add A or deionized water until the value of the c is in the center value range, standing, centrifuging the supernatant after standing, and taking the centrifuged supernatant to detect the color.

[0032] In some embodiments of the present application, when the c is not in the center value range, continuing to add A or deionized water until the value of the c is in the center value range includes:

[0033] When the value of c is higher than the central value range, continue to add deionized water until the value of c is within the central value range; when the value of c is lower than the central value range, continue to add component A until the value of c is within the central value range.

[0034] In some embodiments of the present application, the temperature of the standing is 20-25℃, such as 25℃; the time is 8-12 min, such as 10 min.

[0035] In some embodiments of the present application, the speed of the centrifugation is above 400 rpm, such as 800-1200 rpm, and specifically can be 1000 rpm; the time of the centrifugation is 2-3 min, such as 2 min. The centrifugation is performed in a centrifuge.

[0036] In some embodiments of the present application, the colorimetric full-process of the lyocell fiber production system refers to the process from slurry-gel solution-spinning bath.

[0037] The raw materials used in the present application are not particularly limited and can be generally commercially available.

[0038] In order to further illustrate the present application, a lyocell fiber production system colorimetric full-process detection method provided by the present application is described in detail below in combination with examples, but it should not be understood as limiting the scope of protection of the present application.

[0039] In the examples, the slurry is composed of three substances, including cellulose, NMMO and water. In the slurry, the mass content of cellulose is 10.5%, and the mass content of NMMO is 64%.

[0040] The gel solution is composed of three substances, including cellulose, NMMO and water. In the gel solution, the mass content of cellulose is 12%, and the mass content of NMMO is 73%.

[0041] Example 1

[0042] Lyocell fiber production system colorimetric full-process detection method:

[0043] 1) 10 g of slurry and 20 g of deionized water are stirred and mixed at 60℃ for 5 min, and the supernatant after mixing is taken to detect the concentration of N-methyl morpholine-N-oxide (abbreviated as NMMO) as 31.1%, denoted as c;

[0044] 2) continue to add deionized water with the mass concentration of NMMO in the spinning bath (23.50%) as the center value range ± 0.5%, until the value of c is in the center value range (23.20%), stand for 10 min, centrifuge the supernatant after standing in the centrifuge (1000 rpm) for 2 min, and take the centrifuged supernatant to detect the colority.

[0045] After detection (detection wavelength of 200-800 nm by ultraviolet spectrophotometer), the colority is 224.

[0046] Example 2

[0047] Colority whole-process detection method of lyocell fiber production system:

[0048] 1) 10 g of pulp and 20 g of deionized water are stirred and mixed at 65°C for 5 min, and the mass concentration of N-methyl morpholine-N-oxide (NMMO for short) in the mixed supernatant is detected to be 32.5%, denoted as c;

[0049] 2) continue to add deionized water with the mass concentration of NMMO in the spinning bath (23.50%) as the center value range ± 0.5%, until the value of c is in the center value range (23.50%), stand for 10 min, centrifuge the supernatant after standing in the centrifuge (1000 rpm) for 2 min, and take the centrifuged supernatant to detect the colority.

[0050] After detection (detection wavelength of 200-800 nm by ultraviolet spectrophotometer), the colority is 225.

[0051] Example 3

[0052] Colority whole-process detection method of lyocell fiber production system:

[0053] 1) 10 g of pulp and 20 g of deionized water are stirred and mixed at 65°C for 10 min, and the mass concentration of N-methyl morpholine-N-oxide (NMMO for short) in the mixed supernatant is detected to be 33.4%, denoted as c;

[0054] 2) continue to add deionized water with the mass concentration of NMMO in the spinning bath (23.50%) as the center value range ± 0.5%, until the value of c is in the center value range (23.40%), stand for 10 min, centrifuge the supernatant after standing in the centrifuge (1000 rpm) for 2 min, and take the centrifuged supernatant to detect the colority.

[0055] After detection (detection wavelength of 200-800 nm by ultraviolet spectrophotometer), the colority is 224.

[0056] Example 4

[0057] A method for detecting the color of a lyocell fiber production system throughout the whole process:

[0058] 1) 10 g of dope was mixed with 80 g of deionized water at 60°C for 5 min, and the supernatant after mixing was taken to detect the mass concentration of N-methylmorpholine-N-oxide (NMMO) as 7.9%, denoted as c;

[0059] 2) with the mass concentration of NMMO in the spinning bath (23.50%) ± 0.5% as the center value range, dope was continuously added until the value of c was within the center value range (22.80%), and the supernatant after standing for 10 min was centrifuged (at a speed of 1000 rpm) for 2 min, and the supernatant after centrifugation was taken to detect the color.

[0060] After detection (using an ultraviolet spectrophotometer to detect, with a detection wavelength of 200-800 nm), the color was 245.

[0061] Example 5

[0062] A method for detecting the color of a lyocell fiber production system throughout the whole process:

[0063] 1) 10 g of dope was mixed with 80 g of deionized water at 65°C for 5 min, and the supernatant after mixing was taken to detect the mass concentration of N-methylmorpholine-N-oxide (NMMO) as 8.1%, denoted as c;

[0064] 2) with the mass concentration of NMMO in the spinning bath (23.50%) ± 0.5% as the center value range, dope was continuously added until the value of c was within the center value range (22.70%), and the supernatant after standing for 10 min was centrifuged (at a speed of 1000 rpm) for 2 min, and the supernatant after centrifugation was taken to detect the color.

[0065] After detection (using an ultraviolet spectrophotometer to detect, with a detection wavelength of 200-800 nm), the color was 249.

[0066] Example 6

[0067] A method for detecting the color of a lyocell fiber production system throughout the whole process:

[0068] 1) 10 g of dope was mixed with 80 g of deionized water at 65°C for 10 min, and the supernatant after mixing was taken to detect the mass concentration of N-methylmorpholine-N-oxide (NMMO) as 8.51%, denoted as c;

[0069] 2) continue to add the glue solution with the mass concentration of NMMO in the spinning bath (23.50%) ± 0.5% as the central value range, until the value of c is in the central value range (22.90%), stand for 10 min, centrifuge the supernatant after standing in the centrifuge (1000 rpm) for 2 min, and take the supernatant after centrifugation to detect the colority.

[0070] After detection (detection wavelength: 200-800 nm), the colority is 242.

[0071] The above examples are only used to help understand the method of the present application and its core idea. Various modifications to these examples will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other examples without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these examples shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for full-process colorimetric detection in a lyocell fiber production system, comprising the following steps: S1) Mix component A with deionized water, and take the supernatant after mixing to detect the mass concentration of N-methylmorpholine-N-oxide, which is recorded as c; component A is a porridge or a gel. S2) Using the mass concentration of N-methylmorpholine-N-oxide in the spinning bath ±0.5% as the center value range, when the c is within the center value range, let it stand, centrifuge the supernatant after standing, and take the supernatant after centrifugation to detect the color; when the c is not within the center value range, continue to add A or deionized water until the value of c is within the center value range, let it stand, centrifuge the supernatant after standing, and take the supernatant after centrifugation to detect the color.

2. The colorimetric full-process detection method according to claim 1, characterized in that, The porridge or gel contains three substances: cellulose, NMMO, and water.

3. The colorimetric full-process detection method according to claim 2, characterized in that, The porridge or gel contains 9% to 14% cellulose and 54% to 90% NMMO by mass.

4. The colorimetric full-process detection method according to claim 1, characterized in that, The mass ratio of component A to deionized water is 1:2~100.

5. The colorimetric full-process detection method according to claim 1, characterized in that, The mixing temperature is 55~65℃.

6. The colorimetric full-process detection method according to claim 1, characterized in that, The mixing time is 3 to 7 minutes.

7. The colorimetric full-process detection method according to claim 1, characterized in that, The settling time is 8-12 minutes.

8. The colorimetric full-process detection method according to claim 1, characterized in that, The centrifuge speed is above 400 rpm.

9. The colorimetric full-process detection method according to claim 8, characterized in that, The centrifuge speed is 800~1200 rpm.

10. The colorimetric full-process detection method according to claim 1, characterized in that, The centrifugation time is 2-3 minutes.