Separation method of blended fabric

Abstract

A blended fabric separation method includes: soaking a blended fabric in a solvent to allow materials of the blended fabric to react with the solvent to obtain a first mixture, the materials of the blended fabric include polyethylene glycol terephthalate and cellulose, the solvent includes 2, 2, 6, 6-tetramethylpiperidine oxide, sodium bromide and sodium hypochlorite, and the 2, 2, 6, 6-tetramethylpiperidine oxide is a mixture of 2, 2, 6, 6-tetramethylpiperidine oxide, sodium bromide and sodium hypochlorite; the molar concentration ratio of 2, 2, 6, 6-tetramethylpiperidine oxide to sodium bromide is greater than or equal to 0.05 and less than or equal to 0.21; the first mixture is filtered and separated to obtain recycled cloth and a second mixture, and the recycled cloth is made of polyethylene glycol terephthalate; and filtering and separating the second mixture to obtain a plurality of nanocelluloses. The recycled cloth obtained through the separation method of the blended cloth can keep high structural integrity, polyethylene glycol terephthalate in the recycled cloth can meet the requirements of granulation and laddering, nanocellulose with high utilization value can be recycled through the separation method, and circular economy and environmental friendliness can be achieved.

Description

Technical Field

[0001] The present invention relates to a method for separating composite fabrics, and in particular to a method for separating blended fabrics. Background Art

[0002] In the field of textiles, blended fabrics can embody the advantages of multiple materials at the same time, so they are widely manufactured by textile manufacturers. If blended fabrics can be recycled and reused as resources, it will not only effectively alleviate environmental pressure, but also have important significance for the sustainable development of the textile industry. However, the common separation methods currently used will destroy the overall structure of blended fabrics, and the recycled materials often do not meet the requirements of the granulation and spinning process, resulting in the inability to simply use recycled materials to re-prepare new fabrics, but the need to add additional pure materials, making it difficult to completely achieve a circular economy and improve environmental protection. Summary of the invention

[0003] The present invention provides a method for separating blended fabrics. The recycled fabric obtained by the separation method can maintain high structural integrity, and the polyethylene terephthalate in the recycled fabric can meet the requirements of the granulation and spinning process. In addition, the separation method can recycle nanocellulose with high utilization value, and can achieve circular economy and environmental protection.

[0004] According to some embodiments of the present invention, a method for separating a blended fabric comprises: soaking the blended fabric in a solvent, allowing the material of the blended fabric to react with the solvent to obtain a first mixture, wherein the material of the blended fabric comprises polyethylene terephthalate and cellulose, the solvent comprises 2,2,6,6-tetramethylpiperidinyl oxide, sodium bromide and sodium hypochlorite, and the molar concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide to sodium bromide is greater than or equal to 0.05 and less than or equal to 0.21; filtering and separating the first mixture to respectively obtain recycled fabric and a second mixture, wherein the material of the recycled fabric comprises polyethylene terephthalate; and filtering and separating the second mixture to obtain a plurality of nanocelluloses.

[0005] In some embodiments of the present invention, the blended fabric includes 40 to 80 parts by weight of polyethylene terephthalate and 20 to 60 parts by weight of cotton.

[0006] In some embodiments of the present invention, the material of the recycled cloth includes cotton, and the weight residual rate of the cotton in the recycled cloth is greater than or equal to 0.19% and less than or equal to 1.10%.

[0007] In some embodiments of the present invention, the blended fabric includes 50 to 90 parts by weight of polyethylene terephthalate and 10 to 50 parts by weight of rayon.

[0008] In some embodiments of the present invention, the second mixture is filtered and separated to obtain nanocellulose and a third mixture, and the method for separating the blended fabric further comprises reacting the third mixture with a solvent.

[0009] In some embodiments of the present invention, the molar concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide to sodium hypochlorite is greater than or equal to 0.005 and less than or equal to 0.019.

[0010] In some embodiments of the present invention, the reaction temperature of the blended fabric and the solvent is greater than or equal to 15° C. and less than or equal to 35° C., and the reaction pressure is greater than or equal to 1000 hPa and less than or equal to 1030 hPa.

[0011] In some embodiments of the present invention, the weight recovery rate of polyethylene terephthalate in the recycled cloth is greater than or equal to 93.4% and less than or equal to 99.5%.

[0012] In some embodiments of the present invention, the viscosity of polyethylene terephthalate in the recycled cloth is tested according to the GB / T 14190-93 standard method, and the intrinsic viscosity of polyethylene terephthalate is greater than or equal to 0.550 and less than or equal to 0.641.

[0013] In some embodiments of the present invention, the total carboxyl content in the nanocellulose is greater than or equal to 1.00 mmol / g and less than or equal to 1.30 mmol / g.

[0014] According to the above embodiment of the present invention, by controlling the concentration of 2,2,6,6-tetramethylpiperidinyl oxide in the solvent, the recycled cloth can maintain high structural integrity, and the polyethylene terephthalate in the recycled cloth can further meet the requirements of the granulation and spinning process, and nanocellulose with high utilization value can be efficiently recovered. In addition, the solvent used to separate the blended cloth can be reused, realizing circular economy and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to make the above and other objects, features, advantages and embodiments of the present invention more clearly understood, the following are the descriptions of the accompanying drawings:

[0016] Figure 1 A flow chart showing a method for separating blended fabrics according to some embodiments of the present invention is shown;

[0017] Figure 2 The reaction mechanism of TEMPO / NaBr / NaClO solvent system on cellulose is shown;

[0018] Figure 3A , 4A , 5A and 6A are respectively microscopic schematic diagrams of the blended fabrics of Examples 1 to 4;

[0019] Figure 3B , 4B , 5B and 6B are respectively microscopic schematic diagrams of recycled fabrics obtained by separation of the blended fabrics of Examples 1 to 4, wherein the ultrasonic vibration process is not used;

[0020] Figure 3C , 4C , 5C and 6C are respectively microscopic schematic diagrams of recycled fabrics obtained by separation of the blended fabrics of Examples 1 to 4, wherein an ultrasonic oscillation process is used during separation;

[0021] Fig. 7A and 7B Complete photographs of the blended fabric of Example 1 before and after separation are shown respectively.

[0022] Wherein, the reference numerals are:

[0023] S10~S30: Steps DETAILED DESCRIPTION

[0024] The following will disclose multiple embodiments of the present invention with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary and therefore should not be used to limit the present invention. In addition, in order to simplify the drawings, some commonly used structures and components will be illustrated in a simple schematic manner in the drawings. In addition, for the convenience of readers, the sizes of the components in the drawings are not drawn according to the actual scale.

[0025] The present invention relates to a method for separating blended fabrics, which includes reacting the blended fabrics in a solvent to obtain recycled fabrics containing polyethylene terephthalate (PET) and nanocellulose. The molecular weight of the cotton fiber is reduced and separated from the blended fabric by the action of 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) oxidizing cellulose in the solvent, while the recycled fabric (i.e., polyethylene terephthalate) does not react with 2,2,6,6-tetramethyl-piperidine-1-oxyl, so it can still maintain high structural integrity and meet the requirements of the granulation and spinning process, thereby improving the convenience of the recycled fabric in subsequent applications. In addition, by controlling the concentration ratio of 2,2,6,6-tetramethyl-piperidine-1-oxyl in the solvent, nanocellulose with high utilization value can also be efficiently recovered. On the other hand, the present invention is used to make the solvent for separating the blended fabric reusable, realize a circular economy, and improve environmental protection.

[0026] See also Figure 1 , which depicts a flow chart of a method for separating blended fabrics according to some embodiments of the present invention. The method for separating blended fabrics comprises steps S10 to S30. In step S10, the blended fabric is reacted in a solvent to obtain a first mixture. In step S20, the first mixture is filtered and separated to obtain a recycled fabric and a second mixture, respectively. In step S30, the second mixture is filtered and separated to obtain a plurality of nanocelluloses. In the following description, each of the above steps will be described in detail in sequence.

[0027] First, in step S10, the blended fabric is immersed in a solvent to react with the solvent to obtain a first mixture. In the present invention, the materials of the blended fabric include polyethylene terephthalate and cellulose (natural fiber or regenerated fiber, such as cotton, rayon), and the solvent includes 2,2,6,6-tetramethylpiperidinyl oxide, sodium bromide (NaBr) and sodium hypochlorite (NaClO) (referred to as TEMPO / NaBr / NaClO solvent system). Since the TEMPO / NaBr / NaClO solvent system can quickly oxidize hydroxyl groups into carboxyl groups, the cellulose in the blended fabric can be efficiently oxidized into nanocellulose with high utilization value, and the TEMPO / NaBr / NaClO solvent system causes little damage to cellulose and hemicellulose during oxidation. Specifically, please refer to Figure 2 , which depicts the reaction mechanism of TEMPO / NaBr / NaClO solvent system to cellulose. Figure 2 The reaction mechanism shows that the TEMPO / NaBr / NaClO solvent system is a cyclic oxidation system, that is, the TEMPO / NaBr / NaClO solvent system can be recycled and reused, which is environmentally friendly.

[0028] In the present invention, by controlling the concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide in the solvent, the recovered cloth obtained later can maintain high structural integrity. Specifically, the present invention designs the molar concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide to sodium bromide to be greater than or equal to 0.05 and less than or equal to 0.21 (for example, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17 or 0.19 or any value in the aforementioned range). In detail, if this molar concentration ratio is less than 0.05, it is easy to cause insufficient reactivity of the TEMPO / NaBr / NaClO solvent system, and it is impossible to efficiently separate the blended cloth; if this molar concentration ratio is greater than 0.21, in addition to increasing the cost of the solvent (agent), it is easy to cause excessive reactivity, resulting in too fast oxidation rate, making the size of the formed cellulose too small, and increasing the difficulty of recovery and filtration. In some embodiments, in order to match the molar concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide to sodium bromide, the molar concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide to sodium hypochlorite can be designed to be greater than or equal to 0.005 and less than or equal to 0.019 (for example, 0.008, 0.011, 0.014, 0.017 or any value in the aforementioned range), so that the entire TEMPO / NaBr / NaClO solvent system has sufficient oxidation driving force. It is worth noting that through the TEMPO / NaBr / NaClO solvent system of the present invention and the concentration design of each component therein, it is not necessary to cut the blended fabric into small sizes before reacting, that is, the present invention will not be limited by the original size of the blended fabric when recycling (separating) the blended fabric.

[0029] In addition, if the recycled cloth is to be further melted and reused, by controlling the concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide in the solvent within the aforementioned range, the polyethylene terephthalate in the recycled cloth can have a suitable intrinsic viscosity (IV value), which can meet the requirements of the granulation and spinning process. Furthermore, by controlling the concentration ratio of 2,2,6,6-tetramethylpiperidinyl oxide in the solvent within the aforementioned range, the recovered nanocellulose can also have a high total carboxyl content. In detail, the total carboxyl content in nanocellulose affects the dispersibility of nanocellulose in water. If the total carboxyl content in nanocellulose is too low, nanocellulose cannot be evenly dispersed in water, resulting in nanocellulose having only a relatively low-level utilization value, such as as a reinforcing material.

[0030] In some embodiments, the blended fabric may include 40 to 80 parts by weight of polyethylene terephthalate and 20 to 60 parts by weight of cotton, preferably 40 to 65 parts by weight of polyethylene terephthalate and 35 to 60 parts by weight of cotton. In other embodiments, the blended fabric may include 50 to 90 parts by weight of the polyethylene terephthalate and 10 to 50 parts by weight of rayon, preferably 65 to 70 parts by weight of the polyethylene terephthalate and 29 to 35 parts by weight of rayon. The present invention can achieve good separation effects for blended fabrics containing the above-mentioned proportions of components.

[0031] In some embodiments, 2,2,6,6-tetramethylpiperidinyl oxide and sodium bromide may be uniformly mixed according to the above ratio to form a mixed solution, and the blended fabric may be placed in the mixed solution for stirring, and then sodium hypochlorite may be added to the mixed solution to react the blended fabric in the solvent. In some embodiments, the reaction temperature of the blended fabric and the solvent may be greater than or equal to 15°C and less than or equal to 35°C, and the reaction pressure of the blended fabric and the solvent may be greater than or equal to 1000 hPa and less than or equal to 1030 hPa. In the above temperature range, 2,2,6,6-tetramethylpiperidinyl oxide and sodium hypochlorite will not lose activity due to excessive temperature, and the above temperature range and pressure range are easily accessible atmospheric temperature ranges and atmospheric pressure ranges, which greatly improves the convenience of the reaction, and the reaction time is only about 3 hours to 6 hours. In some embodiments, a base (such as NaOH) may be added to maintain the pH value of the solvent above 10 (for example, 10 to 12).

[0032] In some embodiments, an ultrasonic oscillation process can be added during the reaction of the blended fabric in the solvent to reduce the residual rate of cellulose (such as cotton or rayon) in the recycled fabric. In detail, during the reaction, the cotton or rayon coated in the blended fabric is not easy to contact the agent, so it cannot be completely reacted into nanocellulose. Based on this, the ultrasonic oscillation process can effectively allow the agent to enter the fiber of the blended fabric for reaction, and the cotton or rayon stuck in the recycled fabric can also be detached by ultrasonic oscillation, thereby reducing the residual rate of cellulose in the recycled fabric. In some embodiments, the ultrasonic oscillation process can be performed in an "interval oscillation" manner, that is, an oscillation is performed once at a fixed reaction time interval, which can enhance the oscillation effect and shorten the reaction time. For example, after reacting for 0.5 hours to 1.0 hours, the oscillation can be performed for 3 minutes to 10 minutes. On the other hand, since the TEMPO / NaBr / NaClO solvent system of the present invention can react at room temperature and pressure, the "interval oscillation" is feasible and convenient (for example, the ultrasonic oscillation process can be performed without worrying about whether the heat source is removed). After completing step S10 , a first mixture generated by the reaction of the blended fabric and the solvent can be obtained.

[0033] Subsequently, in step S20, the first mixture is filtered and separated to obtain a recycled cloth and a second mixture. In detail, a filter screen or filter paper with suitable specifications (e.g., suitable mesh size) can be selected and filtered and separated with a gas pressure pump to collect solids to obtain a recycled cloth with high structural integrity and containing polyethylene terephthalate, and collect liquids to obtain a second mixture, wherein the second mixture includes a solvent, reacted cotton or rayon, and other by-products generated during the reaction. In some embodiments, the recycled cloth can be directly reused after simple washing and drying (e.g., drying at a temperature of 45° C. to 60° C.) because it retains its structural integrity.

[0034] Then, in step S30, the second mixture is filtered and separated to obtain nanocellulose. In detail, a filter screen or filter paper of different specifications (e.g., different mesh sizes) can be selected from step S20, and a gas pressure pump is used to filter and separate to collect solids and obtain nanocellulose. In some embodiments, since sodium hypochlorite is consumed as the reaction time advances, and unreacted cellulose may still exist in the second mixture, sodium hypochlorite can be supplemented during step S10, so that unreacted cellulose can be further reacted into nanocellulose before filtering out nanocellulose, thereby improving the recovery rate of nanocellulose. In addition, the nanocellulose obtained by the separation method of the blended fabric of the present invention has high dimensional stability. In some embodiments, the particle size of nanocellulose can be maintained in a range of greater than or equal to 419 nanometers and less than or equal to 437 nanometers, and the particle size of nanocellulose is measured using a laser particle size analyzer.

[0035] In some embodiments, the second mixture is filtered and separated to further collect liquid to obtain a third mixture, and the third mixture can be placed back into the TEMPO / NaBr / NaClO solvent system to react with the solvent system to increase the respective recovery rates of polyethylene terephthalate and nanocellulose by repeated, cyclic reactions. In some embodiments, after filtering and separating the second mixture, sodium hypochlorite can be supplemented to its initial molar concentration and then placed back into the TEMPO / NaBr / NaClO solvent system. In some embodiments, the third mixture can be placed in the TEMPO / NaBr / NaClO solvent system together with another batch of blended fabrics for reaction.

[0036] In the following description, various evaluations will be conducted on the separation method of the blended fabric of the present invention to specifically describe the efficacy of the content of the present invention. It should be understood that the materials used, their content and proportion, processing details and processing flow, etc. can be appropriately changed without exceeding the scope of the present invention. Therefore, the present invention should not be interpreted restrictively by the embodiments described below. The description of each embodiment is shown in Table 1.

[0037] Table 1

[0038]

[0039] <Experimental Example 1: Structural Integrity of Recycled Cloth>

[0040] In this experimental example, a TEMPO / NaBr / NaClO solvent system was used to react with the blended fabrics of Examples 1 to 4, wherein the molar concentration of TEMPO was 0.64 mM to 1.28 mM, the molar concentration of NaBr was 3.05 mM to 12.14 mM, the molar concentration of NaClO was 48 mM to 121 mM, the reaction temperature of the blended fabric and the solvent was 20°C to 30°C, and the reaction pressure of the blended fabric and the solvent was 1010 hPa to 1014 hPa. After the reaction is completed, the solids are collected by filtration and washing, and dried at a temperature of 45°C to 60°C to obtain recycled fabric. For actual photos of the blended fabrics of Examples 1 to 4 and the recycled fabrics obtained after separation of the blended fabrics of Examples 1 to 4, please refer to FIG. 3A to FIG. 6C ,in Figure 3A , Figure 4A , Figure 5A and Fig. 6A They are microscopic schematic diagrams of the blended fabrics of Examples 1 to 4 respectively; Figure 3B , Figure 4B , Figure 5B and Figure 6B Schematic diagrams of micrographs of recycled fabrics obtained by separation of the blended fabrics of Examples 1 to 4, respectively, wherein the ultrasonic vibration process is not used; Figure 3C , Figure 4C , Figure 5C and Figure 6C Schematic micrographs of recycled fabrics obtained by separating the blended fabrics of Examples 1 to 4, respectively, wherein an ultrasonic vibration process is used during the separation.

[0041] Depend on Figure 3B , 4B , 5B and 6B and Figure 3C , 4C , 5C and 6C, it can be seen that in the recycled cloth obtained by the separation method of the present invention, multiple fibers are still firmly interwoven, and although the gaps between the fibers are slightly larger, the entire cloth still maintains a high structural integrity. Fig. 7A and Figure 7BThe complete photos of the blended fabric of Example 1 before and after separation are shown respectively. Fig. 7A It can be seen that the blended fabric can be separated without cutting or grinding into small size. Figure 7B It can be seen that the recycled cloth still has the shape of a whole piece of cloth. Figure 3C , 4C , 5C and 6C, it can be seen that no cellulose residue is observed in the recycled fabric obtained by using the ultrasonic oscillation process during separation. The present invention further uses a TEMPO / NaBr / NaClO solvent system with different concentration ratios to separate the blended fabric. The results show that when the concentration ratio of TEMPO and the composition and ratio of the blended fabric are as described above, the recycled fabric with a complete structure can be recovered.

[0042] <Experimental Example 2: Weight recovery rate and IV value of PET in recycled fabric>

[0043] In this experimental example, the measurement Figure 3C , Figure 4C , Figure 5C and Figure 6C The weight recovery rate of PET in the recycled fabrics is defined as [weight of PET in the recycled fabric / weight of PET in the blended fabric] × 100%; and the IV value of commercially available pure PET fabrics is measured using the GB / T14190-93 standard method. Figure 3C , Figure 4C , Figure 5C and Figure 6C The IV value of PET in the recycled cloth. The measurement results are shown in Table 2, where Figure 3C and Figure 4C The two sets of data are obtained by repeating the same experiment twice using Examples 3 and 4. Figure 3C For example, the blended fabric of Example 3 was used to conduct a first experiment to obtain a first set of data, and the solvent recovered from the first experiment was used to conduct a second experiment on another batch of blended fabrics of Example 3 to obtain a second set of data; Figure 4C For example, the first experiment was conducted using the blended fabric of Example 4 to obtain a first set of data, and the solvent recovered from the first experiment was used to conduct a second experiment on another batch of blended fabrics of Example 4 to obtain a second set of data. This proves that the present invention can be used to make the separated solvent of the blended fabrics recyclable, thereby achieving circular economy and environmental protection.

[0044] Table 2

[0045]

[0046]

[0047] From the results in Table 2, it can be seen that in the recycled cloth, the weight recovery rate of PET is greater than or equal to 93.4% and less than or equal to 99.5%, and the IV value of the recycled PET is greater than or equal to 0.550 and less than or equal to 0.641. It can be seen that the separation method of the blended cloth of the present invention can almost recycle all PET with a high recovery rate, and the IV value of the recycled PET is very close to the IV value of pure PET. Therefore, if the recycled PET is to be melted and reused, the recycled PET can be directly subjected to a granulation and spinning process without the need to add additional pure materials, so that the recycled PET has a high utilization rate. The present invention further uses a TEMPO / NaBr / NaClO solvent system of various concentrations to separate the blended fabrics, and measures the weight recovery rate and IV value of PET. The results show that when the concentration ratio of TEMPO and the components and ratios of the blended fabrics are as described above, the weight recovery rate of PET can fall within the range of 93.4% and 99.5%, and the IV value of the recovered PET can fall within the range of 0.550 and 0.641. The weight recovery rate of PET and the IV value of PET can fall within any range of the values ​​mentioned in Table 2.

[0048] <Experimental Example 3: Residual cellulose rate in recycled cloth and total carboxyl content in recycled nanocellulose>

[0049] In this experimental example, a TEMPO / NaBr / NaClO solvent system was used to react with the blended fabrics of Examples 5 to 8, wherein the molar concentration of TEMPO is shown in Table 3, and the molar concentration ratio of TEMPO to NaBr is 0.07 to 0.11, and the molar concentration ratio of TEMPO to NaClO is 0.007 to 0.012, the reaction temperature of the blended fabric and the solvent is 20°C to 30°C, and the reaction pressure of the blended fabric and the solvent is 1010 hPa to 1014 hPa, an ultrasonic oscillation process is used during separation, and the material of the blended fabric includes 65 parts by weight of polyethylene terephthalate and 35 parts by weight of cotton. After the reaction is completed, the solid is collected by filtration and washing, and dried at a temperature of 45°C to 60°C to obtain a recycled fabric; the cellulose residual rate in the recycled fabric is measured; and the total carboxyl content in the recycled nanocellulose is measured using a carboxylate titration method known in the art. The measurement results are shown in Table 3, wherein the multiple sets of data of Example 5 and Example 7 are obtained by repeating the same experiments for multiple times.

[0050] Table 3

[0051]

[0052] From the results in Table 3, it can be seen that in the recycled cloth, the weight residual rate of cellulose (cotton) is greater than or equal to 0.19% and less than or equal to 1.10%. It can be seen that the recycled cloth obtained by the separation method of the blended cloth of the present invention has almost no residual cellulose and has high purity. On the other hand, since the total carboxyl content in the recycled nanocellulose is greater than or equal to 1.00 mmol / g and less than or equal to 1.30 mmol / g, that is, it has a certain content of carboxyl groups, it is conducive to the uniform dispersion of nanocellulose in water and has high utilization. The present invention further uses a variety of different concentrations of TEMPO / NaBr / NaClO solvent systems to separate blended fabrics, and measures the cellulose residue rate in the recovered fabrics and the total carboxyl content in the recovered nanocellulose. The results show that when the TEMPO concentration ratio and the components and ratios of the blended fabrics are as described above, the weight residue rate of cellulose can fall within the range of 0.19% and 1.10%, and the total carboxyl content in the nanocellulose can fall within the range of 1.00 mmol / g and 1.30 mmol / g. The weight residue rate of cellulose (cotton) and the total carboxyl content in the nanocellulose can fall within any range of the values ​​mentioned in Table 3.

[0053] According to the above embodiment of the present invention, by controlling the concentration of 2,2,6,6-tetramethylpiperidinyl oxide in the solvent, the recycled cloth can maintain high structural integrity, and the polyethylene terephthalate in the recycled cloth can further meet the requirements of the granulation and spinning process, and nanocellulose with high utilization value can be efficiently recovered. In addition, the solvent used to separate the blended cloth can be reused, realizing circular economy and environmental protection.

[0054] Although the present invention has been disclosed as above in the form of an implementation method, it is not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined by the attached claims.

Claims

1. A method for separating blended fabrics, characterized in that: include: Soaking a blended fabric in a solvent to react the material of the blended fabric with the solvent to obtain a first mixture, wherein the material of the blended fabric includes polyethylene terephthalate and cellulose, the solvent includes 2,2,6,6-tetramethylpiperidinyl oxide, sodium bromide and sodium hypochlorite, and the molar concentration ratio of the 2,2,6,6-tetramethylpiperidinyl oxide to the sodium bromide is greater than or equal to 0.05 and less than or equal to 0.21; filtering and separating the first mixture to obtain a recycled cloth and a second mixture, respectively, wherein the recycled cloth is made of polyethylene terephthalate; and The second mixture is filtered and separated to obtain a plurality of nanocelluloses.

2. The method for separating blended fabrics according to claim 1, characterized in that: The blended fabric comprises 40 to 80 parts by weight of the polyethylene terephthalate and 20 to 60 parts by weight of cotton.

3. The method for separating blended fabrics according to claim 2, characterized in that: The material of the recycled cloth includes the cotton, and the weight residual rate of the cotton in the recycled cloth is greater than or equal to 0.19% and less than or equal to 1.10%.

4. The method for separating blended fabrics according to claim 1, characterized in that: The blended fabric comprises 50 to 90 parts by weight of the polyethylene terephthalate and 10 to 50 parts by weight of rayon.

5. The method for separating blended fabrics according to claim 1, characterized in that: The second mixture is filtered and separated to obtain the nanocelluloses and a third mixture respectively, and the blended fabric separation method further comprises reacting the third mixture with the solvent.

6. The method for separating blended fabrics according to claim 1, characterized in that: The molar concentration ratio of the 2,2,6,6-tetramethylpiperidinyl oxide to the sodium hypochlorite is greater than or equal to 0.005 and less than or equal to 0.

019.

7. The method for separating blended fabrics according to claim 1, characterized in that: The reaction temperature of the blended fabric and the solvent is greater than or equal to 15° C. and less than or equal to 35° C., and the reaction pressure is greater than or equal to 1000 hPa and less than or equal to 1030 hPa.

8. The method for separating blended fabrics according to claim 1, characterized in that: The weight recovery rate of the polyethylene terephthalate in the recycled cloth is greater than or equal to 93.4% and less than or equal to 99.5%.

9. The method for separating blended fabrics according to claim 1, characterized in that: The viscosity of the polyethylene terephthalate in the recycled cloth is tested according to the GB / T14190-93 standard method. The intrinsic viscosity of the polyethylene terephthalate is greater than or equal to 0.550 and less than or equal to 0.

641.

10. The method for separating blended fabrics according to claim 1, characterized in that: The total carboxyl content in the nanocellulose is greater than or equal to 1.00 mmol / g and less than or equal to 1.30 mmol / g.

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