Method for detecting components of bi-component fiber product

Abstract

The invention relates to the technical field of fiber product detection, in particular to a method for detecting components of a bi-component fiber product. The detection method comprises the following steps: cutting a product to be detected; drying the sample strip to constant weight, and recording the absolute dry mass of the sample strip before dissolution; dissolving the sample strip by using a copper ethylenediamine solution; drying the dissolved solid-phase substance to constant weight, and recording the absolute dry mass of the dissolved sample strip; sampling, dyeing and flaking the dried solid-phase substances, and observing whether all the solid-phase substances are synthetic fibers or not by using a fiber analyzer; if yes, carrying out subsequent calculation to calculate the components of the bi-component fiber product; and if not, repeating the previous steps, and changing the dissolving conditions until the solid-phase substances are all synthetic fibers observed by a fiber analyzer. The invention provides a component detection method for a bi-component fiber product, and the detection method pays attention to the simplicity and convenience of operation and the stability of a result while ensuring the accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of fiber product detection, and in particular to a method for detecting components of a two-component fiber product. Background Art

[0002] Fiber raw materials include plant-derived fibers and synthetic fibers. Plant-derived fibers include wood pulp fibers, cotton, linen, mulberry, bamboo and other native plant cellulose fibers and viscose fibers, lyocell fibers (Tencel) and other regenerated cellulose fibers; plant-derived fibers have the advantages of natural environmental protection, good skin affinity, and good water absorption. Synthetic fibers include polyester (polyester fiber), nylon, acrylic fiber, spandex, vinylon, etc.; synthetic fibers have the advantages of high strength, not easy to shed, and economical. With the continuous improvement of people's living standards, the types of functional fiber composite materials or products on the market are also increasing, such as non-woven fabrics, wet wipes, soft towels, wet toilet paper, wallpaper and other two-component fiber products, which are new products composed of a plant-derived fiber and a synthetic fiber. However, at present, such products have uneven quality. When consumers use such products, the actual performance of the products will not match the product ingredients claimed on the product packaging. For example, the use of products with a high content of plant-derived fibers will still have problems such as poor skin affinity and low water absorption, which will cause consumers to lose trust in such products and market confusion, affecting the further expansion of such products in the market. Summary of the invention

[0003] In order to solve or partially solve the problems existing in the related art, the present invention provides a method for detecting the composition of a two-component fiber product.

[0004] The present invention provides a method for detecting the composition of a bicomponent fiber product, comprising:

[0005] Step a), cutting the product to be tested to obtain a sample strip;

[0006] Step b), take the sample strip and dry it to constant weight, and record the absolute dry mass of the sample strip before dissolution as m1;

[0007] Step c), using a copper ethylenediamine solution to dissolve the sample strip;

[0008] Step d), filtering, washing and collecting the dissolved mixture to obtain a dissolved solid phase;

[0009] Step e), drying the dissolved solid phase to constant weight, and recording the absolute dry mass of the dissolved sample strip as m2;

[0010] Step f), sampling, dyeing and slice-making the dried solid phase, and using a fiber analyzer to observe whether the solid phase is all synthetic fibers; if so, proceed to step g); if not, repeat steps b) to f), and change the dissolution conditions of step c) until the solid phase is observed to be all synthetic fibers by a fiber analyzer; the dissolution conditions include one or more of the following conditions: the amount of copper ethylenediamine solution, the dissolution temperature, and the dissolution time;

[0011] Step g), calculate the composition of the bicomponent fiber product according to Formula I and Formula II:

[0012] P 合成纤维 =m2 / m1×100% Formula I

[0013] P 植物源纤维 =1-P 合成纤维 Formula II

[0014] In Formula I and Formula II:

[0015] P 合成纤维 is the content of synthetic fiber in the bicomponent fiber product, %;

[0016] m1 is the absolute dry mass of the sample strip before dissolution, g;

[0017] m2 is the absolute dry mass of the sample strip after dissolution, g;

[0018] The bicomponent fiber product is composed of a plant-derived fiber and a synthetic fiber.

[0019] Furthermore, in the step a), the length of the sample strip is 30-70 mm, and the width is 3-6 mm.

[0020] Furthermore, in the step b) and the step e), the drying temperature is 100-110°C.

[0021] Furthermore, in the step c), the concentration of copper ions in the copper ethylenediamine solution is 0.25 to 2.0 mol / L.

[0022] Furthermore, the step b) is specifically as follows:

[0023] Step b1), put the sample strip into the test bottle, add a number of glass beads and copper ethylenediamine solution into the test bottle, cover the bottle with a stopper, and then shake well;

[0024] Step b2), shaking the test bottle regularly.

[0025] Furthermore, the step b2) is specifically as follows:

[0026] Place the test bottle in a water bath and shake the test bottle periodically.

[0027] Furthermore, the temperature of the water bath is 30-50° C., the time is 10-30 min; and the time interval of the timed shaking is 3-8 min.

[0028] Furthermore, the stain used in step e) is Herzberg stain or Graff C stain.

[0029] Furthermore, the bicomponent fiber product is one or more of wet wipes, soft towels, wet toilet paper, non-woven fabrics, and wallpaper.

[0030] Furthermore, it is characterized in that the plant-derived fiber is one of wood pulp fiber, bamboo fiber, hemp fiber, mulberry fiber, viscose fiber, and lyocell fiber; and the synthetic fiber is one of polyester fiber, nylon, acrylic fiber, spandex, and vinylon.

[0031] The method for detecting the composition of a bicomponent fiber product provided by the present invention may have the following beneficial effects:

[0032] 1. This method provides a component detection method suitable for two-component fiber products composed of a plant-based fiber and a synthetic fiber, which fills the gap in the current lack of component detection of such products and provides a reliable component detection method for two-component fiber products. It provides effective detection means for relevant companies and market regulators to ensure the authenticity and transparency of the ingredients of such products, which helps to promote the establishment of industry standards and improve product quality, and enhance consumers' trust in products.

[0033] 2. This detection method uses copper ethylenediamine solution as a dissolving agent to dissolve plant-derived fibers and retain synthetic fibers, thereby achieving accurate quantification of the two fiber components. This method is not only applicable to regenerated cellulose fibers, such as viscose and lyocell fibers, but also to native plant cellulose fibers, such as wood pulp, bamboo, mulberry, etc., which expands the scope of application of the detection method. In addition, the use of copper ethylenediamine solution as a dissolving agent simplifies the traditional sulfuric acid dissolution process and the subsequent neutralization and washing steps, making the entire operation simpler and faster.

[0034] 3. Through the observation of the fiber analyzer, it can be intuitively verified whether the plant-derived fiber is fully dissolved during the dissolution process. The test results are stable and accurate.

[0035] In summary, the present invention provides a method for detecting the composition of a two-component fiber product, which not only ensures accuracy but also focuses on simplicity of operation and stability of results.

[0036] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0038] Figure 1 This is a fiber analysis microphotograph of Group 1 in Example 1 of the present invention, and the magnification of the photo is 100 times. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0041] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various information in the present invention, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0042] The inventors of this application have found that the main reason for the above problems is not the quality difference of the raw materials themselves, but the fact that the actual composition of the product does not match the product ingredients claimed on the packaging. Therefore, an accurate determination method is needed to quantitatively determine the fiber ratio to ensure the authenticity and transparency of the product ingredients. However, there is currently no corresponding detection method for bicomponent fiber products.

[0043] The inventor of the present application searched for existing relevant testing methods and found that GB / T 2910.11-2009 Quantitative chemical analysis of textiles Part 11: Mixture of cellulose fibers and polyester fibers (sulfuric acid method) describes a method that is the closest to achieving quantitative determination of the fiber composition of the above-mentioned two-component material. Its principle is to dissolve the cellulose fibers in the sample through a 75% concentrated sulfuric acid solution, then neutralize and filter, collect the undissolved polyester fiber part, and finally dry and weigh it. However, the following problems exist when applying this method to the detection of two-component fiber products:

[0044] 1) This method is only applicable to regenerated cellulose fibers such as viscose and lyocell (Tencel), and is not applicable to native plant cellulose fibers such as wood pulp, bamboo, and mulberry, so its scope of application is relatively small. If this method is used to measure wet wipes made of wood pulp and synthetic fibers, the wood pulp fibers will not be completely dissolved, resulting in poor stability of the test results. The reason may be that the wood pulp fibers in the wet wipes base fabric are relatively short. During the dissolution process of 75% sulfuric acid, the outer layer of the wood pulp fibers is prone to dissolve too quickly to form a colloid, which wraps the inner layer of fibers and cannot be fully dissolved, resulting in unstable test results.

[0045] 2) The reagent used in this method is 75% concentrated acid, which is highly corrosive. After dissolution, it needs to be filtered, neutralized with ammonia water and washed with cold water, and the operation process is also complicated.

[0046] In response to the above market demands and current technical conditions, the inventors of the present application are considering providing a method for quantitatively determining the fiber components of plant-based fibers and synthetic fiber composite materials for two-component fiber products, which has good result stability and is easy to operate.

[0047] The embodiment of the present invention provides a method for detecting the composition of a bicomponent fiber product, characterized by comprising:

[0048] Step a), cutting the product to be tested to obtain a sample strip;

[0049] Step b), take the sample strip and dry it to constant weight, and record the absolute dry mass of the sample strip before dissolution as m1;

[0050] Step c), using a copper ethylenediamine solution to dissolve the sample strip;

[0051] Step d), filtering, washing and collecting the dissolved mixture to obtain a dissolved solid phase;

[0052] Step e), drying the dissolved solid phase to constant weight, and recording the absolute dry mass of the dissolved sample strip as m2;

[0053] Step f), sampling, dyeing and slice-making the dried solid phase, and using a fiber analyzer to observe whether the solid phase is all synthetic fibers; if so, proceed to step g); if not, repeat steps b) to f), and change the dissolution conditions of step c) until the solid phase is observed to be all synthetic fibers by a fiber analyzer; the dissolution conditions include one or more of the following conditions: the amount of copper ethylenediamine solution, the dissolution temperature, and the dissolution time;

[0054] Step g), calculate the composition of the bicomponent fiber product according to Formula I and Formula II:

[0055] P 合成纤维 =m2 / m1×100% Formula I

[0056] P 植物源纤维 =1-P 合成纤维 Formula II

[0057] In Formula I and Formula II:

[0058] P 合成纤维 is the content of synthetic fiber in the bicomponent fiber product, %;

[0059] m1 is the absolute dry mass of the sample strip before dissolution, g;

[0060] m2 is the absolute dry mass of the sample strip after dissolution, g;

[0061] The bicomponent fiber product is composed of a plant-derived fiber and a synthetic fiber.

[0062] In the above detection method, step a) is the step of cutting the product to be tested to obtain a sample strip, which provides the necessary samples for subsequent tests. The smaller the size of the sample strip, the more conducive it is to shorten the subsequent dissolution time. However, the inventors of this application have found through research that if the size of the sample strip is too small, the solid phase will not be easy to collect and dry after the dissolution is completed. Therefore, the sample used in the subsequent detection of this application is in the form of a strip, which can not only shorten the dissolution time, but also facilitate the washing, collection, drying and weighing of the solid phase after dissolution. Furthermore, the length of the sample strip is 30 to 70 mm, and the width is 3 to 6 mm.

[0063] Step b) is a step of drying the sample strip and recording the mass. The purpose of this step is to determine the initial absolute dry mass of the sample strip before the dissolution treatment, and to provide a reference for subsequent mass changes. The drying temperature of this step is preferably 100-110°C, and most preferably 105°C.

[0064] Step c) is a step of dissolving the sample strip using a copper ethylenediamine solution. Copper ethylenediamine has good solubility for native plant fibers and is currently mainly used to test pulp viscosity. The inventors of the present application found that copper ethylenediamine also has good solubility for regenerated cellulose fibers and the dissolution conditions are mild. Therefore, it is considered to use copper ethylenediamine solution as a dissolving agent to dissolve the plant-derived fiber components in the sample strip, and then collect, dry and measure the remaining synthetic fiber components, thereby calculating the contents of the two components.

[0065] 75% concentrated sulfuric acid dissolution includes two reactions: chemical hydrolysis and physical dissolution. The copper ethylenediamine solution is mainly pure physical dissolution, with mild dissolution conditions and good solubility for both native plant fibers and regenerated cellulose fibers. In addition, the dissolution process using the copper ethylenediamine solution and the collection process of the undissolved part after dissolution are both simpler and more operable. Therefore, the sample strip is dissolved using the copper ethylenediamine solution, and the plant-derived fibers in the sample strip can be dissolved under mild conditions, and the synthetic fibers in the sample strip can be retained to achieve the separation of the plant-derived fibers and the synthetic fibers. The synthetic fiber components after dissolution are collected and dried, and the contents of the two components can be calculated. In addition, the dissolution process and the collection process of the undissolved part are simple to operate. In this step, the concentration of copper ions in the copper ethylenediamine solution is preferably 0.25-2.0 mol / L.

[0066] In order to improve the dissolution efficiency, the above step b) is preferably:

[0067] Step b1), put the sample strip into the test bottle, add a number of glass beads and copper ethylenediamine solution into the test bottle, cover the bottle with a stopper, and then shake well;

[0068] Step b2), shaking the test bottle regularly.

[0069] The above-mentioned test bottle can be a plastic bottle or a glass bottle with a stopper, etc. The addition of glass beads can play a stirring role during the shaking process, help accelerate the dissolution process, and ensure that the sample strip and the copper ethylenediamine solution are fully mixed.

[0070] Generally, fiber composite materials can be dissolved at room temperature. For special hard-to-dissolve materials, a water bath can promote the dissolution process to ensure that the plant-derived fibers in different composite materials can be fully dissolved, thereby ensuring the accuracy of the test results. The above step b2) is preferably:

[0071] Place the test bottle in a water bath and shake the test bottle periodically.

[0072] More preferably, the temperature of the water bath is 30-50° C., and the time is 10-30 min; the time interval of the timed shaking is 3-8 min, for example, the test bottle is shaken once every 5 min.

[0073] For two-component composite materials, their manufacturing processes and product states are different, which will have different degrees of influence on the dissolution process. Therefore, during the determination process, whether the plant-derived fiber can be well dissolved is a very important point to ensure the accuracy of the test results. In addition, there are obvious differences in the morphology of plant-derived fibers and synthetic fibers. For example, native plant fibers such as wood pulp fibers and bamboo fibers are generally of different lengths, thicknesses, and wall thicknesses. In addition, there are many types of plant fibers. For example, coniferous wood includes fir and pine, and pine is divided into northern pine and southern pine, etc., and broad-leaved wood is divided into poplar, eucalyptus, birch, etc. Therefore, different morphological characteristics facilitate qualitative identification of fiber types, but also bring difficulties to quantitative determination. Because the dissolution state and dissolution rate of different plant-derived fibers during the dissolution process are also different, therefore, under fixed dissolution conditions, it is very necessary to effectively judge the end point of dissolution. Especially for experiments similar to dissolution, if the parallelism is not good, it is closely related to whether the dissolution process is complete. In order to ensure the accuracy and stability of the test results, the present invention adopts the above steps d) to f):

[0074] Steps d) and e) are the process of collecting and weighing the dissolved synthetic fiber components, specifically, filtering, washing and collecting the dissolved mixture. Filtering can be performed using filter cloth, and washing can be performed using tap water. The collected solid phase is mainly synthetic fiber, which is then dried to remove residual water, and then weighed to obtain the absolute dry mass of the dissolved solid, which is the absolute dry mass of the dissolved sample strip.

[0075] Step f) is a step of using a dyeing method to determine whether the plant-derived cellulose in step c) is sufficiently dissolved. The dye used in step f) is preferably a Herzberg dye or a Graff C dye.

[0076] The judgment result of this step affects whether the absolute dry mass m2 of the dissolved sample strip obtained in step e) can be used to calculate the component content. The specific judgment method is to use a fiber analyzer to observe whether the solid phase is all synthetic fibers. If so, it means that step c) is completely dissolved, that is, the absolute dry mass m2 of the dissolved sample strip obtained in e) is the absolute dry mass of the synthetic fibers in the sample strip, and the content of plant-derived fibers and synthetic fibers in the two-component fiber product can be calculated according to the subsequent step g). If the solid phase observed by a fiber analyzer is not all synthetic fibers, it means that step c) is not completely dissolved, that is, the absolute dry mass m2 of the dissolved sample strip obtained in e) is not the absolute dry mass of the synthetic fibers in the sample strip, but also includes the mass of the residual plant fibers. This mass value cannot be used to calculate the components of the two-component fiber product. At this time, it is necessary to repeat the above steps b) to f) and adjust the dissolution conditions of step c) at the same time. The dissolution conditions include: the amount of copper ethylenediamine solution, the dissolution temperature, and the dissolution time. For example, one or more methods such as increasing the amount of copper ethylenediamine solution, increasing the dissolution temperature (using a water bath for heating, or increasing the temperature of the water bath for heating), and extending the dissolution time can be used to increase the solubility of the plant-based fiber in step c) to ensure that the plant-based fiber is fully dissolved by copper ethylenediamine in this step and improve the accuracy of the detection. Step g) can only be performed after the fiber analyzer is used to observe whether all the solid phases are synthetic fibers.

[0077] Use a fiber analyzer to observe whether all the solid phase is synthetic fiber, which indicates that the plant-derived fiber in step c) is fully dissolved. The absolute dry mass of the sample strip in step e) is m2, which is the absolute dry mass of the synthetic fiber. Therefore, according to the absolute dry mass of the sample strip before dissolution is m1 and the absolute dry mass of the sample strip after dissolution is m2, the accurate content of synthetic fiber and plant-derived fiber in the two-component fiber product can be calculated according to Formula I and Formula II in step g).

[0078] The above detection method provided in the embodiment of the present invention is suitable for detecting one or more bicomponent fiber products among wet wipes, soft towels, wet toilet paper, non-woven fabrics, and wallpapers. The plant-derived fiber in the bicomponent fiber product can be one of wood pulp fiber, bamboo fiber, hemp fiber, mulberry fiber, viscose fiber, and lyocell fiber; the synthetic fiber can be one of polyester fiber, nylon, acrylic fiber, spandex, and vinylon. For the specific types of plant-derived fibers and synthetic fibers, that is, qualitative identification can be carried out according to the FZ / T 01057 Textile Fiber Identification Test Method Series Standard and GB / T 4688-2020 Analysis of Paper, Paperboard and Pulp Fiber Composition.

[0079] From the above content, it can be seen that the method for detecting the composition of a bicomponent fiber product provided by the embodiment of the present invention has the following advantages:

[0080] 1. This method provides a component detection method suitable for two-component fiber products composed of a plant-based fiber and a synthetic fiber, which fills the gap in the current lack of component detection of such products and provides a reliable component detection method for two-component fiber products. It provides effective detection means for relevant companies and market regulators to ensure the authenticity and transparency of the ingredients of such products, which helps to promote the establishment of industry standards and improve product quality, and enhance consumers' trust in products.

[0081] 2. This detection method uses copper ethylenediamine solution as a dissolving agent to dissolve plant-derived fibers and retain synthetic fibers, thereby achieving accurate quantification of the two fiber components. This method is not only applicable to regenerated cellulose fibers, such as viscose and lyocell fibers, but also to native plant cellulose fibers, such as wood pulp, bamboo, mulberry, etc., which expands the scope of application of the detection method. In addition, the use of copper ethylenediamine solution as a dissolving agent simplifies the dissolution process and the subsequent neutralization and washing steps, making the entire operation simpler and faster.

[0082] 3. Through the observation of the fiber analyzer, it can be intuitively verified whether the plant-derived fiber is fully dissolved during the dissolution process. The test results are stable and accurate.

[0083] In summary, the present invention provides a method for detecting the composition of a two-component fiber product, which not only ensures accuracy but also focuses on simplicity of operation and stability of results.

[0084] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0085] The stains in the following examples are all Herzberg stains.

[0086] Example 1

[0087] Randomly select one wet wipe from each of three packs of a certain brand, wash the wet wipes with tap water, and then unfold the washed wet wipes. Cut a 50mm×50mm wet wipe block from the middle part, and then continue to cut it into sample strips with a width of 3mm. Three groups of sample strips (respectively recorded as Group 1 to Group 3) are placed in three aluminum boxes, dried to constant weight, and then weighed, and the absolute dry mass of the samples is recorded. The three groups of sample strips are placed in three plastic bottles, and 10 small glass beads and about 50mL of copper ethylenediamine solution with a copper ion concentration of 2 mol / L are added to the plastic bottles. The bottles are covered with stoppers and shaken vigorously. After shaking for 10 minutes, the stoppers are opened, and the undissolved parts in the bottle are filtered, washed, and collected with filter cloth, and then placed in an aluminum box again, dried to constant weight, and weighed, and the absolute dry mass of the solid phase after treatment is recorded. From the solid phase after weighing, samples are taken for dyeing, preparation of films, and microscopic observation with a fiber analyzer. The fiber analysis micrograph of Group 1 is shown as follows. Figure 1As shown, only synthetic fibers were observed in all three groups of samples, indicating that the dissolution process was sufficient and the results were valid. The test results are shown in Table 1:

[0088] Table 1 Test results of Example 1

[0089]

[0090] Note: The actual content of synthetic fibers is provided by the manufacturer.

[0091] It can be seen from Table 1 that the synthetic fiber content detected is consistent with the actual content. The detection results of this method have good stability and high accuracy.

[0092] Example 2

[0093] Randomly select one piece from each of the three packs of a certain brand of soft towel, take a 50mm×50mm soft towel block from the middle, and then continue to cut it into sample strips with a width of 6mm. Three groups of sample strips (respectively recorded as Group 1 to Group 3) were placed in three aluminum boxes and dried to constant weight, and then weighed, and the absolute dry mass of the sample was recorded. The three groups of sample strips were placed in three plastic bottles, 10 small glass beads and about 12.5mL of copper ethylenediamine solution with a copper ion concentration of 2mol / L were added to the plastic bottles, and deionized water was added to the plastic bottles to a total volume of 50mL. After the bottle stopper was covered, the plastic bottle was placed in a 30℃ water bath pot for water bath insulation for 20min. Shake once every 5min during the period. After the water bath is over, open the bottle stopper, filter, wash and collect the undissolved part in the bottle with a filter cloth, and then put it in the aluminum box again, dry it to constant weight and weigh it, and record the absolute dry mass of the solid phase after treatment. After weighing, the solid phase was sampled, dyed, sliced, and observed under a fiber analyzer. Only synthetic fibers were observed in all three groups of samples, indicating that the dissolution process was sufficient and the results were valid. The test results are shown in Table 2:

[0094] Table 2 Example 2 Test results

[0095]

[0096] Note: The actual content of synthetic fibers is provided by the manufacturer.

[0097] It can be seen from Table 2 that the synthetic fiber content detected is consistent with the actual content. The detection results of this method have good stability and high accuracy.

[0098] Example 3

[0099] Randomly select one sheet from each of three packs of a certain brand of wet toilet paper and wash the wet toilet paper with tap water. Unfold the washed wet toilet paper separately, then take a 50mm×50mm wet toilet paper block from the middle, and then continue to cut it into sample strips with a width of 3mm. Three groups of sample strips (respectively recorded as Group 1 to Group 3) are placed in three aluminum boxes and dried to constant weight, then weighed, and the absolute dry mass of the samples is recorded. The three groups of sample strips are placed in three plastic bottles respectively, 10 small glass beads and about 25mL of copper ethylenediamine solution with a copper ion concentration of 1mol / L are added to the plastic bottles, and the bottles are covered with stoppers and shaken vigorously. After shaking for 20 minutes, open the bottle stopper, filter, wash and collect the undissolved part in the bottle with a filter cloth, and then put it into the aluminum box again, dry it to constant weight and weigh it, and record the absolute dry mass of the solid phase after treatment. After weighing, the solid phase was sampled, dyed, sliced, and observed with a fiber analyzer. Only synthetic fibers were observed in all three groups of samples, indicating that the dissolution process was sufficient and the results were valid. The test results are shown in Table 3:

[0100] Table 3 Example 3 test results

[0101]

[0102] Note: The actual content of synthetic fibers is provided by the manufacturer.

[0103] It can be seen from Table 3 that the synthetic fiber content detected is consistent with the actual content. The detection results of this method have good stability and high accuracy.

[0104] Example 4

[0105] Randomly cut 3 50mm×50mm sample blocks from a non-woven wallpaper, and then continue to cut into sample strips with a width of 3mm. Three groups of sample strips (respectively recorded as Group 1 to Group 3) were placed in 3 aluminum boxes and dried to constant weight, and then weighed, and the absolute dry mass of the samples was recorded. The three groups of sample strips were placed in 3 plastic bottles, and 10 small glass beads and about 50mL of copper ethylenediamine solution with a copper ion concentration of 1mol / L were added to the plastic bottles. After the bottle stopper was covered, the plastic bottle was placed in a 50℃ water bath for 30min. Shake once every 5min during the period. After the water bath ended, open the bottle stopper, filter, wash and collect the undissolved part in the bottle with a filter cloth, and then put it into the aluminum box again, dry it to constant weight and weigh it, and record the absolute dry mass of the solid phase after treatment. From the solid phase after weighing, samples were taken for dyeing, film making, and microscopic observation with a fiber analyzer. Only synthetic fibers were observed in the three groups of samples, indicating that the dissolution process was sufficient and the results were valid. The test results are shown in Table 4:

[0106] Table 4 Example 4 Test results

[0107]

[0108] Note: The actual content of synthetic fibers is provided by the manufacturer.

[0109] It can be seen from Table 4 that the synthetic fiber content detected is consistent with the actual content. The detection results of this method have good stability and high accuracy.

[0110] Comparative Example 1

[0111] Randomly select one sheet from each of three packs of a certain brand of wet toilet paper and wash the wet toilet paper with tap water. Unfold the washed wet toilet paper separately, and then take at least 1g from each sheet of wet toilet paper, numbering them 1 to 3. Place the sample in a Soxhlet extractor and extract it with petroleum ether for 1 hour, with at least 6 cycles per hour. After the petroleum ether in the sample evaporates, immerse the sample in cold water for 1 hour, and then soak it in water at (65±5)℃ for 1 hour. In both cases, the bath ratio is 1:100. Stir the solution from time to time, squeeze, filter or centrifuge to remove excess water in the sample, and then dry the sample naturally. Weigh 1g of the extracted sample and add 200mL of sulfuric acid solution (75%) into a conical flask. Put a stopper on the flask, shake the flask to fully wet the sample, keep the flask at 50℃ for 1h, and shake it every 10min. Filter the liquid with a glass crucible. Drain the liquid by vacuum suction, and wash the flask with a small amount of sulfuric acid solution. Drain the liquid by vacuum suction, add new sulfuric acid solution to the crucible to clean the residue by gravity drainage, and then vacuum suction again after at least 1min. Wash with cold water several times in a row, neutralize twice with dilute ammonia water (80mL diluted with water to 100mL), and then wash with cold water. Drain the liquid by gravity first and then vacuum suction each time. Finally, the crucible and the insoluble fiber are dried to constant weight and weighed. The experimental results are shown in Table 5.

[0112] Table 5 Comparative Example 1 Test Results

[0113]

[0114] It can be seen from Table 5 that the synthetic fiber content detected is higher than the actual content. The accuracy of the detection result of this method is low.

[0115] Comparative Example 2

[0116] Randomly cut 3 50mm×50mm sample blocks from a non-woven fabric known to be 100% synthetic fiber material, and continue to cut them into sample strips with a width of 3mm. Three groups of sample strips (respectively recorded as Group 1 to Group 3) were placed in 3 aluminum boxes, dried to constant weight, and then weighed, and the absolute dry mass of the samples was recorded. The three groups of sample strips were placed in 3 plastic bottles, and 10 small glass beads and about 50mL of copper ethylenediamine solution with a copper ion concentration of 1mol / L were added to the plastic bottles. After covering the bottle with the stopper, shake it vigorously for 30 minutes. Open the bottle stopper, filter, wash and collect the undissolved part in the bottle with a filter cloth, and then put it into the aluminum box again, dry it to constant weight and weigh it. The test results are shown in Table 6:

[0117] Table 6 Comparative Example 2 Test Results

[0118] serial number Absolute dry mass of sample / g Absolute dry mass after treatment / g Group 1 0.0754 0.0755 Group 2 0.0699 0.0700 Group 3 0.0788 0.0788

[0119] It can be seen from Table 6 that the mass of the sample did not change after being treated with the copper ethylenediamine solution, indicating that the copper ethylenediamine solution treatment did not dissolve the synthetic fiber.

[0120] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting the composition of a bicomponent fiber product, characterized in that: include: Step a), cutting the product to be tested to obtain a sample strip; Step b), take the sample strip and dry it to constant weight, and record the absolute dry mass of the sample strip before dissolution as m1; Step c), using a copper ethylenediamine solution to dissolve the sample strip; Step d), filtering, washing and collecting the dissolved mixture to obtain a dissolved solid phase; Step e), drying the dissolved solid phase to constant weight, and recording the absolute dry mass of the dissolved sample strip as m2; Step f), sampling, dyeing and slice-making the dried solid phase, and using a fiber analyzer to observe whether the solid phase is all synthetic fibers; if so, proceed to step g); if not, repeat steps b) to f), and change the dissolution conditions of step c) until the solid phase is observed to be all synthetic fibers by a fiber analyzer; the dissolution conditions include one or more of the following conditions: the amount of copper ethylenediamine solution, the dissolution temperature, and the dissolution time; Step g), calculate the composition of the bicomponent fiber product according to Formula I and Formula II: P 合成纤维 =m2 / m1×100% Formula I P 植物源纤维 =1-P 合成纤维 Formula II In Formula I and Formula II: P 合成纤维 is the content of synthetic fiber in the bicomponent fiber product, %; m1 is the absolute dry mass of the sample strip before dissolution, g; m2 is the absolute dry mass of the sample strip after dissolution, g; The bicomponent fiber product is composed of a plant-derived fiber and a synthetic fiber.

2. The detection method according to claim 1, characterized in that: In the step a), the length of the sample strip is 30-70 mm, and the width is 3-6 mm.

3. The detection method according to claim 1, characterized in that: In the steps b) and e), the drying temperature is 100-110°C.

4. The detection method according to claim 1, characterized in that: In the step c), the concentration of copper ions in the copper ethylenediamine solution is 0.25-2.0 mol / L.

5. The detection method according to claim 1, characterized in that: The step b) is specifically as follows: Step b1), put the sample strip into the test bottle, add a number of glass beads and copper ethylenediamine solution into the test bottle, cover the bottle with a stopper, and then shake well; Step b2), shake the test bottle regularly.

6. The detection method according to claim 5, characterized in that: The step b2) is specifically as follows: Place the test bottle in a water bath and shake the test bottle periodically.

7. The detection method according to claim 6, characterized in that: The temperature of the water bath is 30-50° C., and the time is 10-30 min; the time interval of the timed shaking is 3-8 min.

8. The detection method according to claim 1, characterized in that: The stain used in step e) is Herzberg stain or Graff C stain.

9. The detection method according to claim 1, characterized in that: The bicomponent fiber product is one or more of wet wipes, soft towels, wet toilet paper, non-woven fabrics, and wallpaper.

10. The detection method according to claim 1, characterized in that: The plant-derived fiber is one of wood pulp fiber, bamboo fiber, hemp fiber, mulberry fiber, viscose fiber, and lyocell fiber; the synthetic fiber is one of polyester fiber, nylon, acrylic fiber, spandex, and vinylon.

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