Odor detection method for viscose fibers

Abstract

The method comprises the following steps: taking a viscose fiber sample to be detected, adding an alkali solution with the mass concentration of 0.36 + / -0.01% in proportion, and heating to obtain an alkali leaching solution; pure water is used as a reference solution, and the absorbance A of the alkali leaching liquid at 410-430 nm is measured by a spectrophotometer; the method overcomes the defects that an existing olfactory identification method has subjective prejudice and is prone to smell fatigue, the elemental sulfur content detected by an existing viscose residual sulfur content determination method cannot directly reflect the peculiar smell condition of viscose, and existing instruments are expensive and complex to operate. The method comprises the following steps: extracting elemental sulfur and sulfide in a viscose fiber sample by using a dilute alkali solution, controlling the extraction temperature and time to obtain an alkali extraction solution, measuring the absorbance A of the alkali extraction solution at 410-430nm, and judging whether the corresponding viscose fiber is the low-odor viscose fiber or not by judging whether the absorbance A is smaller than a boundary value under the corresponding wavelength or not. The method has the advantage that the peculiar smell condition of the viscose in the wet state can be objectively evaluated with simple operation.

Description

Technical Field

[0001] The invention relates to a method for detecting odor of viscose fibers, which is applied in the technical field of chemical fiber processing. Background Art

[0002] Clean high-white viscose staple fibers are a type of differentiated viscose staple fibers that have been widely used in non-woven medical and sanitary materials. In the domestic industry standard "FZT 54032-2010 Clean High-Whiteness Viscose Staple Fibers", various index requirements that clean high-white viscose staple fibers should meet are given. The standard also discloses a test method for viscose fiber odor, but after using this method to test odor-free viscose fibers made into dry towels, the problem of dry towels emitting odor after being dipped in hot water still occurs, affecting the consumer experience. Therefore, it is necessary to study the evaluation method of odor intensity of viscose fibers in wet state.

[0003] The domestic literature "Research on the Elimination of Odor from Viscose Staple Fibers" (Man-Made Fibers [J], 2017, 47(05): 10-12.) analyzed the reasons why viscose staple fibers produce odor after being soaked in a slightly acidic solution. It is believed that the source of the odor is the sulfide remaining on the viscose fibers. After being treated with citric acid, the sulfide reacts with the citric acid to generate H2S gas with the smell of rotten eggs, which causes the viscose fibers to produce odor. The odor is evaluated by the olfactory method. In Patent ZL202011406400.4 "A Method for Preparing Low-Odor Viscose Fibers", it is also mentioned that the olfactory method is used to evaluate the intensity of the odor. However, the olfactory method is easily affected by subjective bias, and there is a problem of olfactory fatigue caused by long-term testing. Therefore, it is necessary to study an objective method for detecting odors to avoid the problem that dry towel samples made of viscose fibers with low odor levels evaluated by artificial olfactory methods still smell odor after being dipped in hot water.

[0004] Since the intensity of odor is related to the type and concentration of the odor, it would be helpful to evaluate the strength of the odor if the concentration of the odor component could be detected. However, for viscose fibers, since the olfactory threshold of some sulfides is extremely low, it is difficult to evaluate the odor intensity by detecting the concentration of the various material components that emit odor when exposed to hot water. The prior art has disclosed some methods for detecting sulfides or sulfur content, but no reports have been found on these methods being used to evaluate the odor of viscose fibers in wet state. For example, the domestic industry standard "FZ / T 50014-2008 Method for Determination of Residual Sulfur Content in Cellulose Chemical Fibers" (iodine method) can detect the content of sulfur in viscose fibers, but the content of sulfur cannot directly reflect the odor of viscose fibers, and this method is complicated to operate and takes a long time to test. The national ecological environment standard "Determination of Sulfide in Water by Gas Phase Molecular Absorption Spectrometry (HJ 200-2023)" stipulates the determination of sulfide in surface water, groundwater, domestic sewage, industrial wastewater and seawater by gas phase molecular absorption spectrometry. 2- The detection limit is 0.005 mg / L, and the lower limit of determination is 0.020 mg / L. 2- The content of sulfur in viscose fiber can be calculated by the method of gas chromatography-mass spectrometry and electronic nose detection technology, but there is no report on its successful application in the field of viscose fiber odor detection technology, and this detection technology has the disadvantages of expensive instruments and complicated operation.

[0005] Therefore, it is urgent to provide a detection method that can objectively and simply evaluate the odor condition of viscose fibers in a wet state. Summary of the invention

[0006] In order to overcome the disadvantages of subjective bias and olfactory fatigue in the existing olfactory method for judging the strength of the odor of viscose fiber, the sulfur content detected by the existing viscose fiber residual sulfur content determination method cannot directly reflect the odor of the viscose fiber, and the disadvantages of expensive instruments and complicated operations in the gas chromatography-mass spectrometry method and the electronic nose method, the present invention provides an odor detection method for viscose fiber, which extracts sulfur and sulfide in the viscose fiber sample with a dilute alkaline solution, controls the extraction temperature and time to obtain an alkaline extract, determines the absorbance A of the alkaline extract at 410-430nm, and determines whether the corresponding viscose fiber is a low-odor viscose fiber by whether the value is less than the cutoff value at the corresponding wavelength. The method has the advantages of being able to objectively and simply evaluate the odor of the viscose fiber in a wet state.

[0007] The technical solution of the present invention is as follows:

[0008] A method for detecting odor of viscose fiber comprises the following steps performed in sequence:

[0009] (1) Take a viscose fiber sample to be tested, add an alkaline solution with a mass concentration of 0.35-0.37% at a ratio of 40-50 ml / g, and immerse the viscose fiber sample to be tested in the alkaline solution;

[0010] (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature so that the liquid remains in a slightly boiling state for 29 to 31 minutes, then stopping the heating and cooling to 20 to 30° C. to obtain an alkaline leaching solution;

[0011] (3) Using pure water as a reference solution, measure the absorbance A of the alkaline extract at a wavelength of 410 to 430 nm using a spectrophotometer;

[0012] (4) Evaluate the odor of the viscose fiber sample according to the value of absorbance A: if the absorbance A is less than the cutoff value at the corresponding wavelength, it is determined that the viscose fiber sample meets the odor control standard of low-odor viscose fiber; the cutoff value is 0.185-0.235.

[0013] The odor detection method for viscose fiber of the present application uses a dilute alkaline solution to extract sulfur and sulfide in the viscose fiber sample, controls the extraction temperature and time to obtain an alkaline extract, measures the absorbance A of the alkaline extract at a wavelength of 410 to 430 nm, and determines whether the corresponding viscose fiber is a low-odor viscose fiber (corresponding to a wet odor intensity rating value ≤ 1.8) by whether the value is less than the cutoff value at the corresponding wavelength (different wavelengths of absorbance A correspond to different cutoff values), which has the advantage of objectively, simply and effectively evaluating the odor condition of viscose fiber in a wet state. The present application mainly utilizes the residual sulfur or hydrogen sulfide and other odor components of the viscose fiber to react with the alkali to generate colored substances, and selects the absorbance test data of the test liquid in a specific wavelength range to compare the "sulfur" odor concentration, so as to further evaluate the odor intensity and reduce the subjective bias that is easily caused by the existing olfactory identification method when used alone. Its advantages are:

[0014] (1) In a specific wavelength range, the higher the absorbance, the higher the total amount of sulfur and sulfide remaining in the finished fiber that can react with the dilute alkali solution; because the odor of viscose fiber in a wet state is related to the sulfur or sulfide remaining in the fiber, the odor detection method for viscose fiber of the present application can be used as an auxiliary inspection method of the olfactory identification method;

[0015] (2) Compared with the domestic industry standard "FZ / T 50014-2008 Determination of Residual Sulfur in Cellulose Chemical Fibers", the detection method of the present application is easy to operate and is conducive to quickly comparing the amount of residual sulfur to improve the quality of viscose fiber products. Among them, the slightly boiling state refers to the liquid temperature approaching or just beginning to reach the boiling point, the generation of bubbles is relatively small, and it has not reached the intensity of boiling. After the liquid is kept in a slightly boiling state for 29-31 minutes in step (2), the remaining volume of the liquid is about 79-80% of the original volume, which is conducive to ensuring sufficient extraction and avoiding the color of the extract to deepen, resulting in the absorbance value of the test being unsuitable for comparative analysis. The preferred concentration of the alkali solution is conducive to avoiding the generation of a solution with more complex color changes when using concentrated alkali extraction, resulting in the inability to perform comparative analysis of absorbance, and is also conducive to avoiding the need to extend the extraction time or the problem of weak correlation between absorbance and odor intensity when using extremely low concentration alkali solution extraction.

[0016] The wavelength of 410-430nm selected in this application is the preferred absorption wavelength when detecting the absorbance of the colored extract at different wavelengths to ensure accurate and reliable measurement results. The corresponding demarcation value at each wavelength in step (4) can be obtained by comparing the absorbance value A of the alkaline extract of the low-odor viscose fiber prepared by patent ZL202011406400.4 "A method for preparing low-odor viscose fiber" and conventional viscose fiber samples prepared by other methods and conducting research and analysis. For example, the absorbance demarcation value of 0.205 at a wavelength of 420nm is based on the fact that the absorbance of the low-odor viscose fiber samples selected in the embodiment is below 0.195, while the absorbance value of the alkaline extract of the conventional viscose fiber sample is above 0.217, and considering the detection error, the demarcation value is selected as 0.205. Similarly, it can be obtained that the absorbance cutoff value of the alkali extract of low-odor viscose fiber at a wavelength of 430nm is 0.185, and the absorbance cutoff value of the alkali extract of low-odor viscose fiber at a wavelength of 410nm is 0.235.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The instrument used in this application is cheaper than a gas chromatography-mass spectrometer, is easy to operate, and has simple data processing, and can quickly and effectively evaluate the odor status of viscose fibers in a wet state;

[0019] (2) The present application solves the problem that the olfactory method is susceptible to subjective bias and olfactory fatigue, which helps to avoid the problem that a dry towel made of viscose fiber with a low odor level assessed by artificial olfactory method still smells odor after being soaked in hot water;

[0020] (3) The present application adopts sodium hydroxide solution for extraction, optimizes the extraction conditions such as alkali concentration, extraction time, and extraction temperature, and uses the absorbance value of the alkali extract for odor analysis, thereby solving the problem that the residual sulfur content detected by the existing industry standard "FZ / T50014-2008 Method for Determination of Residual Sulfur Content in Cellulose Chemical Fibers" has a weak correlation with the odor intensity.

[0021] The alkaline solution is a sodium hydroxide solution.

[0022] The preferred alkaline solution is readily available and low in cost.

[0023] The mass concentration of the alkaline solution is 0.36%.

[0024] The preferred mass concentration of the alkaline solution is beneficial for avoiding the problem of prolonged extraction time or weak correlation between absorbance and odor intensity when using a lower concentration of alkaline solution for extraction, and is also beneficial for avoiding the problem of generating a solution with more complex color changes when using a higher concentration of alkaline solution for extraction, which makes the detected absorbance value unsuitable for comparative analysis.

[0025] The micro-boiling time in step (2) is 30 min.

[0026] The preferred micro-boiling time ensures sufficient extraction and avoids the generation of longer polysulfide chains that darken the color of the extract and make the detected absorbance value unsuitable for comparative analysis.

[0027] Before adding the alkaline solution in step (1), the viscose fiber sample to be tested is rolled into a cocoon shape.

[0028] Rolling the sample into a cocoon shape helps prevent violent boiling of the liquid, and also helps to avoid the fibers from spreading out and causing the extract to mix with the fiber sample when it is transferred into the cuvette, thus affecting the absorbance detection.

[0029] In step (1), a viscose fiber sample to be tested is taken and an alkaline solution is added at a ratio of 50 ml / g; in step (3), the absorbance A of the alkaline extract at a wavelength of 420 nm is measured by a spectrophotometer; if the absorbance A is less than the cutoff value of 0.205 at a wavelength of 420 nm, it is determined that the viscose fiber sample to be tested meets the odor control standard for low-odor viscose fiber.

[0030] The absorbance cutoff value of 0.205 at a wavelength of 420nm is preferably set to compare with the evaluation method of wet odor intensity grade of viscose fiber (reference patent ZL202011406400.4 "A method for preparing low-odor viscose fiber"). This allows the two to verify each other, making the test results more reliable.

[0031] The viscose fiber sample to be tested in step (1) is 0.50 to 1.00 g.

[0032] The preferred amount of viscose fiber sample to be tested is convenient for rolling into a cocoon shape. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with various specific embodiments.

[0034] Example 1

[0035] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0036] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.0, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0037] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0038] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0039] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.133, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0040] Example 2

[0041] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0042] (1) Take 0.60 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.2, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.35% sodium hydroxide solution at a ratio of 45 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0043] (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 31 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 20° C. to obtain an alkaline leaching solution;

[0044] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0045] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.140, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0046] Example 3

[0047] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0048] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.4, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.37% sodium hydroxide solution at a ratio of 40 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0049] (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 29 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 30° C. to obtain an alkaline leaching solution;

[0050] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0051] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.154, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0052] Example 4

[0053] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0054] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.6, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0055] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0056] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0057] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.164, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0058] Example 5

[0059] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0060] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.8, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0061] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0062] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0063] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.195, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0064] Example 6

[0065] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0066] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 2.0, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0067] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0068] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0069] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.217, which does not meet the absorbance A 420 <cutoff value 0.205, so it is considered that the viscose fiber sample has a heavier odor in wet state.

[0070] Example 7

[0071] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0072] (1) Take 1.00 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.6, roll it into a cocoon shape, place it in a 250 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0073] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0074] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0075] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.161, which satisfies the absorbance A 420 <cutoff value 0.205, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0076] Example 8

[0077] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0078] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 2.2, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0079] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0080] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0081] (4) According to the absorbance A 420 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 420 is 0.318, which does not meet the absorbance A 420 <cutoff value 0.205, so it is considered that the viscose fiber sample has a heavier odor in wet state.

[0082] Example 9

[0083] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0084] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 2.0, roll it into a cocoon shape, place it in a 250 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0085] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0086] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 430 nm was measured using a spectrophotometer. 430 ;

[0087] (4) According to the absorbance A 430 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 430 is 0.197, which does not meet the absorbance A 430 <cutoff value 0.185, so it is considered that the viscose fiber sample has a heavier odor in wet state.

[0088] Example 10

[0089] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0090] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.8, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0091] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0092] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 430 nm was measured using a spectrophotometer. 430 ;

[0093] (4) According to the absorbance A 430 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 430 is 0.178, which satisfies the absorbance A 430 <cutoff value 0.185, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0094] Embodiment 11

[0095] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0096] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 2.0, roll it into a cocoon shape, place it in a 250 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0097] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0098] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 410 nm was measured using a spectrophotometer. 410 ;

[0099] (4) According to the absorbance A 410 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 410 is 0.247, which does not meet the absorbance A 410 <cutoff value 0.235, so it is considered that the viscose fiber sample has a heavier odor in wet state.

[0100] Example 12

[0101] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0102] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.8, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0103] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0104] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 410 nm was measured using a spectrophotometer. 410 ;

[0105] (4) According to the absorbance A 410 The value of the viscose fiber sample alkaline extract absorbance A is used to evaluate the odor of the viscose fiber: 410 is 0.227, which satisfies the absorbance A 410 <cutoff value 0.235, so it is considered that the odor of the viscose fiber sample in wet state is relatively light.

[0106] It can be seen from Examples 1-12 that for low-odor viscose fiber samples with a wet odor intensity rating of ≤1.8, the absorbance obtained by the odor detection method for viscose fiber of the present application satisfies that A is less than the corresponding cutoff value, and for viscose fiber samples with a wet odor intensity rating of >1.8, the absorbance obtained by the odor detection method for viscose fiber of the present application does not satisfy that A is less than the corresponding cutoff value. Therefore, it can be used as a supplementary detection method for the olfactory method to objectively and effectively evaluate the odor condition of viscose fiber in a wet state.

[0107] Equipment information etc. involved in each embodiment:

[0108] Spectrophotometer: Shanghai Sunny Hengping Scientific Instrument Co., Ltd. 7230G;

[0109] Evaluation method for wet odor intensity level of viscose fiber: Refer to the olfactory identification method described in the specification of patent ZL202011406400.4 "A method for preparing low-odor viscose fiber". When the wet odor intensity level is ≤1.8, it is identified as low-odor viscose fiber.

[0110] Experimental data:

[0111] Comparative Example 1

[0112] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0113] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.0, roll it into a cocoon shape, place it in a 100 ml beaker, add 18% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0114] (2) heating the liquid obtained in step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 30 minutes (about 80% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0115] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0116] (4) According to the absorbance A 420 The value of the viscose fiber sample is used to evaluate the odor of the viscose fiber: the absorbance A of the viscose fiber sample is 420 is 0.404, which does not meet the absorbance A 420 <Demarcation value 0.205. If the evaluation method described in the present application is used, the odor of the viscose fiber sample in the wet state is heavier, which is inconsistent with the evaluation result of the olfactory identification method.

[0117] It can be seen that if a higher concentration of alkaline solution is used in this case, an alkaline extract with more complex color changes will be generated, resulting in a test result that is inconsistent with the test result of the olfactory method; from the comparison with Example 1, it can be seen that the concentration of the alkaline solution has a great influence on the odor detection result of the viscose fiber in this case.

[0118] Comparative Example 2

[0119] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0120] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.0, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0121] (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature (about 170° C.) to keep the liquid in a slightly boiling state for 40 minutes (about 70% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0122] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0123] (4) According to the absorbance A 420The value of the viscose fiber sample is used to evaluate the odor of the viscose fiber: the absorbance A of the viscose fiber sample is 420 is 0.208, which does not meet the absorbance A 420 <Demarcation value 0.205. If the evaluation method described in the present application is used, the odor of the viscose fiber sample in the wet state is heavier, which is inconsistent with the evaluation result of the olfactory identification method.

[0124] It can be seen that if the micro-boiling time is too long, a darker alkaline extract will be generated, resulting in the test results being inconsistent with the test results of the olfactory method; from the comparison with Example 1, it can be seen that the duration of the micro-boiling state has a great influence on the odor detection results of the viscose fiber in this case.

[0125] Comparative Example 3

[0126] The method for detecting odor of viscose fiber of the present invention comprises the following steps performed in sequence:

[0127] (1) Take 0.50 g of the viscose fiber sample to be tested with a wet odor intensity rating of 1.0, roll it into a cocoon shape, place it in a 100 ml beaker, add 0.36% sodium hydroxide solution at a ratio of 50 ml / g, immerse the viscose fiber sample to be tested in the sodium hydroxide solution, and cover the opening of the beaker with a watch glass or a flat glass;

[0128] (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature (about 175° C.) to keep the liquid in a boiling state for 30 minutes (about 60% of the liquid volume remains), then stopping the heating, removing the beaker from the heating table, and cooling to 25° C. to obtain an alkaline leaching solution;

[0129] (3) Using pure water as the reference solution, the absorbance A of the alkaline extract at a wavelength of 420 nm was measured using a spectrophotometer. 420 ;

[0130] (4) According to the absorbance A 420 The value of the viscose fiber sample is used to evaluate the odor of the viscose fiber: the absorbance A of the viscose fiber sample is 420 is 0.238, which does not meet the absorbance A 420 <Demarcation value 0.205. If the evaluation method described in the present application is used, the odor of the viscose fiber sample in the wet state is heavier, which is inconsistent with the evaluation result of the olfactory identification method.

[0131] It can be seen that if the heating temperature is selected too high (about 175°C), a darker alkaline extract will be generated, resulting in the test results being inconsistent with the test results of the olfactory method; from the comparison with Example 1 (heating temperature of about 170°C), it can be seen that the heating temperature has a great influence on the odor detection results of the viscose fiber in this case.

Claims

1. A method for detecting odor of viscose fiber, characterized in that: The steps are as follows: (1) Take a viscose fiber sample to be tested, add an alkaline solution with a mass concentration of 0.35-0.37% at a ratio of 40-50 ml / g, and immerse the viscose fiber sample to be tested in the alkaline solution; (2) heating the liquid obtained in the above step (1) to a boiling state, then adjusting the heating temperature so that the liquid remains in a slightly boiling state for 29 to 31 minutes, then stopping the heating and cooling to 20 to 30° C. to obtain an alkaline leaching solution; (3) Using pure water as a reference solution, measure the absorbance A of the alkaline extract at a wavelength of 410 to 430 nm using a spectrophotometer; (4) Evaluate the odor of the viscose fiber sample according to the value of absorbance A: if the absorbance A is less than the cutoff value at the corresponding wavelength, it is determined that the viscose fiber sample meets the odor control standard of low-odor viscose fiber; the cutoff value is 0.185-0.

235.

2. The method for detecting odor of viscose fiber according to claim 1, characterized in that: The alkaline solution is a sodium hydroxide solution.

3. The method for detecting odor of viscose fiber according to claim 1, characterized in that: The mass concentration of the alkaline solution is 0.36%.

4. The method for detecting odor of viscose fiber according to claim 1, characterized in that: The micro-boiling time in step (2) is 30 min.

5. The method for detecting odor of viscose fiber according to claim 1, characterized in that: Before adding the alkaline solution in step (1), the viscose fiber sample to be tested is rolled into a cocoon shape.

6. The method for detecting odor of viscose fiber according to claim 1, characterized in that: In step (1), a viscose fiber sample to be tested is taken and an alkaline solution is added at a ratio of 50 ml / g; in step (3), the absorbance A of the alkaline extract at a wavelength of 420 nm is measured by a spectrophotometer; in step (4), if the absorbance A is less than the cutoff value of 0.205 at a wavelength of 420 nm, it is determined that the viscose fiber sample to be tested meets the odor control standard of low-odor viscose fiber.

7. The method for detecting odor of viscose fiber according to claim 1, characterized in that: The viscose fiber sample to be tested in step (1) is 0.50 to 1.00 g.