CN110219072B - Method for recycling soluble textiles - Google Patents

Abstract

The invention provides a method for recycling soluble textiles, which uses a solvent to dissolve fabrics containing controllable soluble fibers or fabrics made of the controllable soluble fibers, and filters and recovers the dissolved solution to obtain high-purity terephthalic acid and ethylene glycol which are reused for preparing the controllable soluble fibers; and preparing the undissolved textile fibers into high-quality textile fibers for recycling. The solvent has high dissolving speed and small damage to non-soluble fibers, thereby being beneficial to high-quality and high-efficiency reutilization of the fibers.

Description

Reuse method of dissolvable textiles

technical field

The invention relates to the technical fields of fiber processing, textile processing and environmental protection, in particular to a recovery, regeneration and recycling technology of dissolvable textiles.

Background technique

Countless textiles in the world have become waste products that can no longer be used, or are used in a low-level manner, which will cause huge waste of resources and secondary pollution of the environment. Existing textile fibers do not have technologies and products that can be easily processed and recycled. The main reason is that the composition, color, and garment accessories of textile materials are complex;

At present, only high-value textiles such as pure spun cashmere and aramid fibers are opened and carded in the market to obtain fibers with low strength and short length for low-value reuse.

Another recycling route is to recycle PET bottles, and then wash and pelletize them into PET fibers. However, the fiber textiles produced by this method cannot be used in the end and become waste and pollutants. Or the recycled pure PET clothing is obtained by the decomposition method of high temperature melting and chemical alcoholysis to obtain PTA (terephthalic acid), but this method is expensive, and it is only for 100% PET fabrics, and for blended spinning Other non-PET fabrics are not applicable. This method is very limited.

The applicant's prior patent application CN106065085A discloses a technology for the recovery, regeneration and recycling of dissolvable textiles. Garment or injection molding into soluble clothing accessories; the clothes or soluble clothing accessories are dissolved under certain conditions, and on the one hand, the dissolved liquid is filtered and dissolved substances are recovered to obtain high-purity terephthalic acid and ethylene glycol , terephthalic acid and ethylene glycol are reused for the polymerization of soluble polyester to obtain slices of soluble polyester, which can be re-spun into soluble fibers and recycled; on the other hand, the loose undissolved textiles , After treatment, including sterilization, stripping or re-dyeing, it becomes a loose fiber aggregate with good quality. After drying, or after gentle carding, it becomes a high-quality textile fiber, which can be recycled. However, the organic solvent used in this method has a slow dissolution rate, and has certain damage to the insoluble fibers, thus affecting the recycling and reuse of the fibers.

There is a need in the art for a solvent with fast dissolving speed for soluble fibers and less damage to insoluble fibers during the dissolving process, so as to facilitate high-quality and efficient reuse of fibers

SUMMARY OF THE INVENTION

On the basis of patent application CN106065085A (the entire contents of which are incorporated herein by reference), the present invention provides a recycling method for soluble fiber with fast dissolving speed and little damage to insoluble fiber in view of the above-mentioned technical problems. In order to solve the above technical problems at the same time, the present invention provides the following technical solutions.

In one aspect of the present invention, a method for reusing dissolvable textiles is provided, wherein the dissolvable textiles comprise or are made of controlled dissolving fiber fabrics, and the method includes the following steps:

a. For controlled dissolving fiber fabrics, the method includes the following steps:

The controllable dissolving fiber fabric is placed in a container, a solvent is added to make it completely dissolved, and the dissolved solution is filtered, acidified and degassed to obtain terephthalic acid and ethylene glycol, and the COD of the discharged wastewater meets environmental protection requirements ;

or,

b. For blended or interwoven fiber fabrics of controlled dissolving fibers and other non-dissolving fibers, the method includes the following steps:

The fiber fabric is placed in a container, a solvent is added to dissolve it, and the dissolving solution is filtered, acidified and degassed to obtain terephthalic acid and ethylene glycol, and the COD of the waste water is discharged to meet environmental protection requirements; The fibers are dissolved, washed and sterilized to obtain loose fiber aggregates.

Preferably, the raw materials for the preparation of the controllable dissolving fibers include terephthalic acid and/or ethylene glycol.

Preferably, the solvent in step a or b contains organic components.

Preferably, the organic component is DMSO.

Preferably, the solvent further comprises ethanol; or, preferably, the solvent further comprises water.

More preferably, the solvent also contains tetrabutylammonium acetate.

DMSO is bipolar, which has a good swelling effect on fibers. In addition, when tetrabutylammonium acetate is added, due to the strong electronegativity of the acetate ion, it is a very strong hydrogen bond acceptor, which favorably competes with the hydroxyl and acetal oxygen atoms of cellulose, thereby destroying the cellulose The hydrogen bonding network between the chains, so the combined use of DMSO and tetrabutylammonium acetate greatly improves the dissolution rate of soluble fibers.

In a preferred embodiment, based on the total weight of the solvent, in the solvent, the content of ethanol is 40-90 wt%, preferably 50-80 wt%; the content of DMSO is 10-30 wt%, preferably 15- 20%; the content of tetrabutylammonium acetate is 0.1-5.0 wt%, preferably 0.2-2.0 wt%.

More preferably, the solvent in step a or b is alkaline. Further preferably, the solvent contains NaOH. In a preferred embodiment, the solvent further comprises 0.001-5.0 wt%, preferably 0.1-1.0 wt% NaOH, based on the total weight of the solvent.

In a particularly preferred embodiment, the solvent contains an ionic liquid. Preferably, based on the total weight of the solvent, the content of the ionic liquid is 0.1-10.0 wt%, preferably 0.2-5.0 wt%, more preferably 0.5-2.0 wt%.

Particularly preferably, the ionic liquid is the ionic liquid of the following formula (I):

式（I）

Formula (I)

The ionic liquid represented by formula (I) can effectively break the hydrogen bonds in the fibers, so that the fibers can be effectively decomposed under weak solvent pH adjustment. In addition, similarly, due to the strong electronegativity of acetate ions, it acts as a A strong hydrogen bond acceptor, which favorably competes with the hydroxyl and acetal oxygen atoms of cellulose, disrupts the hydrogen bond network between the cellulose chains, which can effectively dissolve fibers. In addition, when the ionic liquid represented by formula (I) is used, due to the strong electron-withdrawing effect of the Cl atom and the polarity of the hydroxyl group, the initial decomposition products generated by the decomposition can be more uniformly and firmly attached to the pore surface of the fiber, so that the Promote the further smooth progress of fiber dissolution, which can prevent the non-uniformity of dissolution. For example, with a high concentration of disintegrating agent, the uniform speed of dissolution can be improved, and the damage to insoluble fibers can be further reduced.

In a preferred embodiment of the present invention, the dissolvable textile is a dissolvable textile prepared by the following method:

(1) Add terephthalic acid, isophthalic acid, ethylene glycol, 5-sodium sulfonate-isophthalic acid polyethylene glycol ester, and select different combinations of the above substances and combinations of substances in different proportions for polymerization , obtain slices, and described slices are the soda-dissolving slices, and then successively carry out casting, cooling, dicing and drying to obtain pellets;

(2) spinning the pellets to prepare controllable dissolving fibers, and using the controllable dissolving fibers to make dissolvable textiles.

Preferably, the spinning temperature is 270-300°C. More preferably, the spinning temperature is 280-290°C.

In a further preferred embodiment of the present invention, a fiber fabric is prepared by blending or interlacing the loose fiber aggregate with the controlled dissolving fiber.

In the present invention, more specifically, the preparation of soluble fibers includes controllable preparation of soluble fibers under different media and different dissolution conditions, including filaments, short fibers and fiber strands;

Textile processing includes: textile design and processing that can be 100% soluble fiber as raw material, or textile processing of soluble fiber blended with other fibers, including clothing accessories for textiles, such as sewing threads, buttons, trademarks, hang tags and water. Shuffle, etc., also composed of soluble substances;

Textile dissolution and recycling: Dissolve under certain conditions, carry out high-purity recycling and sewage treatment for the dissolved soluble fiber material, so as to achieve the purpose of material recovery and sewage reaching environmental protection discharge standards; for 100% soluble fiber textiles, high Purity recovery, the dissolved recyclate can be directly used as the raw material for controllable fiber production, and directly used as the polymer raw material for controllable fiber dissolution; for the dissolution of the blended or interwoven products of the controllable dissolvable fiber, due to the controllable dissolvable fiber Dissolved, the remaining non-dissolved fibers are loose textiles;

Reprocessing of residual textiles: disinfection chemical treatment according to the requirements of use, and stripping or bleaching or re-dyeing treatment according to future use requirements, due to the dissolution of soluble fibers, the remaining textiles will become loose or even disintegrated. Carding, with little damage to fiber strength and little loss of length, to obtain high-quality additional component fibers or bleached or dyed fibers that can be used directly in spinning mills to process new yarns, blends or other components of interwoven textiles The recovered fibers are of high quality and can also be directly used as raw materials for spinning mills, which can achieve efficient and high-quality full-cycle recycling and use of textiles.

The present invention can be realized by the following specific technical solutions.

A recovery, regeneration and recycling technology for dissolvable textiles, comprising the following process steps, specifically:

a. Preparation of soluble fibers and soluble apparel accessories with controlled dissolution conditions:

During the polymerization of the polyester raw material, add terephthalic acid, isophthalic acid, ethylene glycol, 5-sodium sulfonate-polyethylene glycol isophthalate in different proportions of the total weight of the polymer, and select the above The combination of substances and different proportions of substances are polymerized to obtain alkali-dissolved slices under different alkali-dissolving conditions. The intrinsic viscosity of the alkali-dissolved slices is 0.40-0.80. The alkali-dissolved slices are finally completed in sequence. Casting, cooling, dicing, drying and screening process;

(1) According to the conventional spinning process, controllable dissolving fibers are prepared. The controllable dissolving fibers include filaments, short fibers and fiber strips, as well as differentiated and colored fibers of these fibers, which are used in the production of garments, nonwovens Cloth, electrostatic flocking and other textiles;

(2) According to the conventional process, the sewing thread of controllable dissolving fiber is prepared, which can be pure spinning or blended yarn of soluble short fiber, or soluble filament yarn and plied yarn;

(3) According to the conventional injection molding, adding color masterbatch and molding process, using soluble slices with controllable dissolution conditions to produce hard soluble clothing accessories, including zippers, buttons and logos in the form of films, wash tags, ingredient tags, Trademark hang tags, etc.;

or,

b. Preparation of textile dyes and finished products containing soluble fibers:

(1) 100% Controllable Dissolving Fiber Finished Products:

(1-1) Use 100% controlled dissolving fiber, or staple fiber yarn, or filament yarn, use conventional weaving process, if necessary, during dyeing process, that is, do not add dissolved media, such as alkali substances, and the rest The process is the same as that of conventional polyester;

(1-2) The finished product of 100% controllable dissolving fiber plus spandex and other elastic fibers, using the conventional weaving process, if necessary, during the dyeing process, that is, without adding dissolving media, such as alkali substances, the rest of the process is the same as the conventional The processing technology of polyester is the same;

(2) Blended or interwoven products of controllable soluble fibers and other insoluble fibers:

(2-1) Blend or interweave controllable soluble fibers with other insoluble fibers, such as cotton, wool, hemp and other chemical fibers, into finished products, and use conventional weaving techniques, if necessary, during dyeing and processing. Add the dissolved medium, and the rest of the process is the same as the conventional polyester blending or interweaving process;

(2-2) The finished product of blending or interweaving controllable soluble fiber and other insoluble fibers with spandex and other elastic fibers, such as cotton, wool, hemp and other chemical fibers blended and interwoven with spandex and other elastic fiber products, using conventional weaving Process, if necessary, during the dyeing process, that is, without adding dissolved medium, the rest of the process is the same as the conventional polyester blending or interweaving process;

c. Dissolution and recovery of finished products containing soluble fiber and soluble clothing accessories (the soluble clothing accessories can also be regarded as a form of soluble fiber):

(1) Dissolution and recycling of 100% controllable dissolving fiber fabrics and dissolving clothing accessories:

(1-1) Dissolve 100% controlled dissolving fiber fabrics or dissolving clothing accessories directly in various cylinders under certain solvent conditions. For the dissolved liquid, after membrane filtration, acid precipitation, gasification (ie degassing) and other processes, high-purity terephthalic acid, ethylene glycol and NaOH are obtained, and the COD of the discharged wastewater meets the environmental protection requirements;

(1-2) 100% controllable dissolving fiber plus elastic fibers such as spandex or soluble clothing accessories are directly dissolved in various cylinders under certain solvent conditions. For the dissolved solution, after membrane filtration, acid precipitation, gasification and other processes, high-purity terephthalic acid, ethylene glycol and NaOH are obtained, and the COD of the discharged wastewater meets the environmental protection requirements; for elastic fibers such as spandex that are not dissolved, filter The grille is intercepted, the content of this part is small, and it is kept in the form of continuous spandex, which is easy to identify and take away; or use spandex and other elastic fiber solvents to dissolve the spandex elastic fibers. This part has a small amount of solvent and can be recycled and recycled. use;

(2) Dissolving and recycling of blended or interwoven fiber fabrics or soluble clothing accessories of controllable soluble fibers and other insoluble fibers:

Such textiles are directly placed in various cylinders, under the condition of certain solvent medium solubility, to dissolve controllable soluble fibers; at the same time, clean and sterilize insoluble fibers. For insoluble fibers, due to the dissolution of soluble fibers, Make insoluble fibers into loose fiber aggregates;

For the dissolved liquid, after grid filtration, membrane filtration, acid precipitation, gasification and other processes, high-purity terephthalic acid, ethylene glycol and NaOH are obtained, and the COD of the discharged wastewater meets environmental protection requirements;

For the finished products of blended or interwoven elastic fibers such as controllable soluble fibers and other non-soluble fibers, such as cotton, wool, hemp and other chemical fibers blended and interwoven with elastic fibers such as spandex, directly in various cylinders, in Under a certain solubility of the solvent medium, it can dissolve elastic fibers such as controllable dissolving fibers and spandex. Dissolve controllable dissolving fibers; then, use spandex and other elastic fiber solvents to dissolve spandex elastic fibers, and this part of the solvent can be recovered and recycled;

For the already loose and non-dissolving fiber aggregates, it can be regenerated, and disinfectant can be used for disinfection; or directly dried and gently combed, it can be used for variegated fibers; or according to the requirements of regeneration, stripping After bleaching, drying, and gentle carding, it becomes bleached fiber; or the peeled fiber is dyed, dried, and gently carded to become colored fiber. Because it is a loose fiber aggregate, after gentle carding, the strength and length of the fiber are less damaged, which ensures the spinnability and wearability of the non-dissolving fiber;

d. Obtain high-purity chemical raw materials and high-quality fiber materials:

The recovered chemical raw materials after the above treatment: 1. The terephthalic acid, ethylene glycol and NaOH have high purity and are suitable for industrial use; 2. The strength preservation rate of the once-treated regenerated fiber is high, and the length of the regenerated fiber is not lost.

Wherein, the spinning temperature in the step a is 270-300°C, and the injection temperature is 150-250°C.

Wherein, the alkali solution adopted in the step c is sodium hydroxide solution or a low-alkali, alkali-free high-temperature pure aqueous solution or an organic solvent.

The beneficial effects of the present invention are as follows: the recovery, regeneration and recycling technology of dissolvable textiles described in the present invention, for the dissolving liquid after the textiles are dissolved, through grid filtration, membrane filtration, acid precipitation, gasification, etc. After the process, high-purity terephthalic acid, ethylene glycol and NaOH are obtained, and the COD of the discharged wastewater meets the environmental protection requirements; for the blended or interwoven fabrics of soluble fibers, the soluble fibers in the textiles can be dissolved to make the tight textiles, It becomes a loose aggregate of non-dissolving fibers; for the non-dissolving fiber aggregate, it can be regenerated, disinfected, or directly dried and gently combed, and then used for variegated fibers, or peeled off according to the requirements of regeneration. After coloring, bleaching treatment, drying, and gentle carding will become bleached fibers, or the fibers after stripping will be dyed, dried, and gently combed to become colored fibers. It can be used after gentle carding with little damage to the strength and length of the fiber, which ensures the spinnability and wearability of the non-dissolving fiber. The invention makes the textiles, which are worthless and become environmental pollutants, become valuable commodities, that is, the pollution to the environment is reduced, and the textiles can be recycled.

Description of drawings

The present invention is further described below with reference to the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention.

Fig. 1 is the alkali dissolving liquid recovery structure schematic diagram of the present invention;

Figure 2 is a TEM image of fibers dissolved for 20 min according to the prior art method (Comparative Example 1);

Figure 3 is a TEM image of the fibers according to the method of the present invention when they are dissolved for 20 min (Example 1).

Detailed ways

The present invention will be described below with reference to specific embodiments.

Example 1

The technology for dissolving, recycling and reusing 100% controllable soluble fiber fabrics and soluble clothing accessories includes the following process steps, specifically:

a. in the polyester raw material polymerization process, adding the 5-sodium sulfonate-isophthalic acid polyethylene glycol ester that the total polymer weight is 6% and the isophthalic acid that the total polymer weight is 4%, beating and stirring And at the same time be heated to 230 ℃; Then move to the reaction kettle and then add the polyethylene glycol that the total weight of the polymer is 10%, so that it is diluted and cooled to 210 ℃; Continue to add polyethylene glycol in the reaction kettle, this Part of the polyethylene glycol accounts for 10% of the total weight of the polymer. The polyethylene glycol is added within 50 minutes and stirred at the same time. The temperature is raised to 230 ° C under normal pressure and the mixture is polymerized in a vacuum state. The alkali after polymerization is degraded. The slicing finally completes the steps of casting, cooling, dicing, drying and screening in sequence, wherein the intrinsic viscosity of the alkali-degraded slicing is 0.65;

The alkali-soluble degradable filament fiber is prepared by the above-mentioned alkali degradation slices, and the easily alkali-soluble degradable fiber is a filament fiber: wherein, the spinning and post-spinning treatment procedures are: through the conventional POY spinning process, the spinning temperature is 290 ° C, Obtain POY filaments that can be dissolved in alkaline solution, and then, on the texturing machine, produce low elastic yarn DTY; among them, fiber index: 15.5tex/48F fineness, 3.6cn/dtex strength, 25% elongation at break .By conventional spinning process, produce FDY filament, 150D/48F, strength 4.0cn/dtex strength, 20% elongation at break;

b. The above DTY filaments, through conventional processes, produce various fabrics, garments and textiles:

(1) After the above-mentioned FDY filaments are plied and stitched, they are used as sewing threads for textiles;

(2) The above garments and textiles are equipped with clothing accessories, which are hard soluble clothing accessories with soluble chips that have undergone conventional injection molding, masterbatch coloring and molding processes, including zippers, buttons, and film-shaped logos and water. g Shuffle tags, ingredient tags, trademark tags;

c. In a closed common overflow tank of dyeing and finishing plant, add a solvent, the dissolving temperature is 110°C, the dissolving time is 60 minutes, the liquor ratio is 1:10, and the soluble fibers are dissolved. The composition of the solvent is based on Based on the total weight of the solvent, the content of ethanol is 70.0 wt%, the content of DMSO is 25.0 wt%, the content of tetrabutylammonium acetate is 2.0 wt%, 0.2 wt% of NaOH, 2.8 wt% shown in formula (I) ionic liquid;

d. As shown in Figure 1, the controllable dissolving fiber textile is dissolved in the alkaline dissolving solution in the tank, and the dissolving solution is introduced into the adjustment tank after passing through the grid, and the alkaline dissolving solution in the adjustment tank is sequentially pretreated and Membrane system, and the alkali solution passing through the membrane system enters the acid precipitation tank, and the acid solution is pumped into the acid precipitation tank through the acid pump, and the acid solution and the alkali solution are stirred in the acid precipitation tank to obtain a pH value of 3 -4 waste water, during this process, terephthalic acid is precipitated; after the acid solution and the alkali solution are fully reacted in the acid precipitation tank, the wastewater in the acid precipitation tank is introduced into a centrifugal filter for filtration to separate out terephthalic acid. After being filtered and dehydrated by a centrifugal filter, the separated terephthalic acid can be washed or not washed according to different requirements, and stored in bags for shipment. The acid-precipitated filtrate is then passed through a filter membrane system to separate out ethylene glycol. Among them, the grille mainly intercepts larger particles and other large-diameter pollutants in the water, such as impurities and other floating objects, and the adjustment tank is used to buffer the water volume, uniform water quality, and precipitate larger solid particles, so as to facilitate the subsequent processing. The filtrate of the centrifugal filter can greatly reduce the COD of sewage, and the filtrate can be biochemical. After the ethylene glycol is filtered by the membrane system, the COD is further reduced, which meets the discharge requirements of printing and dyeing wastewater, and enters the biochemical wastewater treatment system of the factory.

Example 2

The fiber fabric of the blended yarn fabric of controllable soluble fiber and cellulose fiber and the dissolution, recovery and reuse technology of soluble clothing accessories, which include the following process steps, specifically:

a. The controllable soluble short fibers prepared in Example 1 are blended with cellulose fibers (such as cotton, hemp and rayon), and the blending ratio is 65/35, 50/50, etc.; Cellulose fiber or blended yarn specifications; weaving according to conventional technology; dyeing using polyester and cellulose fiber two-bath method of reactive dyes and disperse dyes dyeing process; thus, obtained fabrics, including woven and knitted fabrics;

(1) After the above-mentioned staple fiber blended yarn is plied and stitched, it is used as a sewing thread for this type of textile;

(2) The above garments and textiles are equipped with clothing accessories, which are hard soluble clothing accessories with soluble chips that have undergone conventional injection molding, masterbatch coloring and molding processes, including zippers, buttons, and film-shaped logos and water. g Shuffle tags, ingredient tags, trademark tags;

b. Cleaning, disinfection and dissolution: dissolve in a closed tank, add solvent, dissolve temperature is 110℃, dissolve time is 60 minutes, bath ratio: 1:10, and add disinfectant and cleaning agent to dissolve soluble fibers and disinfection and cleaning, the composition of the solvent is, based on the total weight of the solvent, the content of ethanol is 70.0 wt%, the content of DMSO is 25.0 wt%, the content of tetrabutylammonium acetate is 2.0 wt%, 0.2 wt% % NaOH, 2.8 wt% ionic liquid shown in formula (I);

As shown in Figure 1, for the discharged dissolved liquid, it is introduced into the adjustment tank after passing through the grid, and the alkaline dissolved liquid in the adjustment tank undergoes pretreatment and the membrane system in turn, and the alkaline dissolved liquid through the membrane system enters the In the acid precipitation tank, the acid solution is pumped into the acid precipitation tank by adding an acid pump, and the acid solution and the alkali solution are stirred in the acid precipitation tank to obtain waste water with a pH value of 3-4. Formic acid is precipitated; after the acid solution and the alkali solution are fully reacted in the acid precipitation tank, the waste water in the acid precipitation tank is introduced into a centrifugal filter for filtration to separate terephthalic acid. After being filtered and dehydrated by a centrifugal filter, the separated terephthalic acid can be washed or not washed according to different requirements, and stored in bags for shipment. The acid-precipitated filtrate is then passed through a filter membrane system to separate out ethylene glycol. Among them, the grille mainly intercepts larger particles and other large-diameter pollutants in the water, such as impurities and other floating objects, and the adjustment tank is used to buffer the water volume, uniform water quality, and precipitate larger solid particles, so as to facilitate the subsequent processing. The filtrate of the centrifugal filter can greatly reduce the COD of sewage, and the filtrate can be biochemical. After the ethylene glycol is filtered by the membrane system, the COD is further reduced, which meets the discharge requirements of printing and dyeing wastewater, and enters the biochemical wastewater treatment system of the factory;

For non-dissolving fibers, color stripping and bleaching are carried out in sequence, in which the color stripping process is carried out by means of reduction and color stripping. Dyeing and drying can also be directly dried with bleached loose aggregates. Finally, the above-mentioned dried cotton fibers are gently combed and opened, the fiber strength and length are less damaged, the spinnability and wearability of the original fibers are maintained, and high-quality regenerated cotton fibers are obtained, so that the cotton fibers can be recycled for subsequent production. High quality yarn.

Example 3

The technology for dissolving, recycling and reusing controllable soluble fiber and cellulose fiber blended yarn plus spandex fiber fabric and soluble clothing accessories includes the following process steps, specifically:

a. The polymerized raw material prepared in Example 1 is subjected to a conventional spinning process to produce short fibers with a length of 38mm and a fineness of 1.5D (3.6cn/dtex strength, 25% elongation at break), which will be controllable Soluble staple fibers, blended with cellulose fibers (such as cotton, hemp and man-made fibers), the blending ratio is 65/35, 50/50, etc., the yarn is interwoven with spandex or doubling elastic yarn, according to the conventional weaving process into woven or knitted fabrics; dyed by reactive dyes and disperse dyes dyeing process of polyester and cellulose fiber two-bath method; thus, fabrics are prepared, including woven and knitted fabrics, and then sewn into finished textile products;

(1) After the above-mentioned staple fiber blended yarn is plied and stitched, it is used as a sewing thread for this type of textile;

(2) The above-mentioned garments and textiles are equipped with clothing accessories, which are hard clothing accessories with soluble chips that have undergone conventional injection molding, masterbatch coloring and molding processes, including zippers, buttons, and film-shaped logos and washing with water. Tag, ingredient tag, trademark tag;

b. Cleaning, disinfection and dissolving: add solvent in a closed tank, the dissolving temperature is 110°C, the dissolving time is 60 minutes, the bath ratio is 1:10, and disinfectant and cleaning agent are added to dissolve and disinfect the soluble fibers and cleaning, the composition of the solvent is, based on the total weight of the solvent, the content of ethanol is 70.0 wt%, the content of DMSO is 25.0 wt%, the content of tetrabutylammonium acetate is 2.0 wt%, and the content of 0.2 wt% NaOH, 2.8 wt% ionic liquid represented by formula (I);

As shown in Figure 1, for the discharged dissolved liquid, it is introduced into the adjustment tank after passing through the grid, and the alkaline dissolved liquid in the adjustment tank undergoes pretreatment and the membrane system in turn, and the alkaline dissolved liquid through the membrane system enters the In the acid precipitation tank, the acid solution is pumped into the acid precipitation tank by adding an acid pump, and the acid solution and the alkali solution are stirred in the acid precipitation tank to obtain waste water with a pH value of 3-4. Formic acid is precipitated; after the acid solution and the alkali solution are fully reacted in the acid precipitation tank, the waste water in the acid precipitation tank is introduced into a centrifugal filter for filtration to separate terephthalic acid. After being filtered and dehydrated by a centrifugal filter, the separated terephthalic acid can be washed or not washed according to different requirements, and stored in bags for shipment. The acid-precipitated filtrate is then passed through a filter membrane system to separate out ethylene glycol. Among them, the grille mainly intercepts larger particles and other large-diameter pollutants in the water, such as impurities and other floating objects, and the adjustment tank is used to buffer the water volume, uniform water quality, and precipitate larger solid particles, so as to facilitate the subsequent processing. The filtrate of the centrifugal filter can greatly reduce the COD of sewage, and the filtrate can be biochemical. After the ethylene glycol is filtered by the membrane system, the COD is further reduced, which meets the discharge requirements of printing and dyeing wastewater, and enters the biochemical wastewater treatment system of the factory;

For the non-dissolved fibers in the tank, add dimethylacetamide (DMAC) liquid, the liquor ratio is 1:1, the temperature is 95 ℃, the time is 30 minutes, and then the dimethylacetamide (DMAC) liquid is discharged and passed through The liquid collector is stored for recycling in the next tank; the non-dissolved fibers are then stripped and bleached in sequence, and the color stripping process is carried out by using the reduction stripping process. Then, it can be dyed and dried according to the dyeing process of conventional bleached cotton as required, or it can be directly dried with bleached loose aggregates. Finally, the above-mentioned dried cotton fibers are gently combed and opened, the fiber strength and length are less damaged, the spinnability and wearability of the original fibers are maintained, and high-quality regenerated cotton fibers are obtained, so that the cotton fibers can be recycled for subsequent production. High quality yarn.

Example 4

The technology for dissolving, recycling and reusing the finished product of the blended fabric of controllable soluble fiber and wool fiber includes the following process steps, specifically:

a. in the polyester raw material polymerization process, adding the 5-sodium sulfonate-isophthalic acid polyethylene glycol ester that the total polymer weight is 10% and the isophthalic acid that the total polymer weight is 4%, beating and stirring And at the same time be heated to 230 ℃; Then move to the reaction kettle and add the polyethylene glycol that the total weight of the polymer is 15%, make it diluted and be cooled to 210 ℃; Continue to add polyethylene glycol in the reaction kettle, this Part of the polyethylene glycol accounts for 15% of the total weight of the polymer. The polyethylene glycol was added within 50 minutes and stirred at the same time. The temperature was raised to 230 ° C under normal pressure and the mixture was polymerized in a vacuum state, and the alkali after the polymerization was degraded. The slicing finally completes the steps of casting, cooling, dicing, drying and screening in sequence, wherein the intrinsic viscosity of the alkali-degraded slices is 0.55;

The above alkali-degraded chips were used to prepare low-alkali-easy-alkali-tolerant short fibers, and the spinning temperature was 275°C. The low-alkali easily soluble fiber is wool-type fiber, with a length of 110 mm, a strength of 2.5 cn/dtex, and an elongation at break of 30%. After carding and slivering, a fiber sliver of 20 g/5 m is obtained. In the production of wool spinning, it is mixed with wool tops to form yarns, the blending ratio is 50 soluble fibers/50 wool fibers, and the Nm is 60 Nm, and the fabrics and textiles are woven according to the conventional process and dyed in an alkali-free state;

(1) After the above-mentioned wool blended yarn is plied and stitched, it is used as a sewing thread for wool blended textiles.

(2) The above-mentioned garments and textiles are equipped with clothing accessories, which are rigid clothing accessories with soluble chips that have undergone conventional injection molding, masterbatch coloring and molding processes, including zippers, buttons, logos in the form of membranes, and water washing. Tag, ingredient tag, trademark tag;

b. Add 100% NaOH 1.5g/L, penetrant 2g/L solvent to a closed tank, the dissolving temperature is 90°C, the dissolving time is 60 minutes, and the bath ratio is 1:10 to dissolve the soluble fibers. The composition of the solvent is, based on the total weight of the solvent, the content of ethanol is 70.0 wt%, the content of DMSO is 25.0 wt%, the content of tetrabutylammonium acetate is 2.0 wt%, 0.2 wt% of NaOH, 2.8 wt% The ionic liquid represented by formula (I);

As shown in Figure 1, for the discharged dissolved liquid, it is introduced into the adjustment tank after passing through the grid, and the alkaline dissolved liquid in the adjustment tank undergoes pretreatment and the membrane system in turn, and the alkaline dissolved liquid through the membrane system enters the In the acid precipitation tank, the acid solution is pumped into the acid precipitation tank by adding an acid pump, and the acid solution and the alkali solution are stirred in the acid precipitation tank to obtain wastewater with a pH value of 3-4. Formic acid is precipitated; after the acid solution and the alkali solution are fully reacted in the acid precipitation tank, the waste water in the acid precipitation tank is introduced into a centrifugal filter for filtration to separate terephthalic acid. After being filtered and dehydrated by a centrifugal filter, the separated terephthalic acid can be washed or not washed according to different requirements, and stored in bags for shipment. The acid-precipitated filtrate is then passed through a filter membrane system to separate out ethylene glycol. Among them, the grille mainly intercepts larger particles and other large-diameter pollutants in the water, such as impurities and other floating objects, and the adjustment tank is used to buffer the water volume, uniform water quality, and precipitate larger solid particles, so as to facilitate the subsequent processing. The filtrate of the centrifugal filter can greatly reduce the COD of sewage, and the filtrate can be biochemical. After the ethylene glycol is filtered by the membrane system, the COD is further reduced, which meets the discharge requirements of printing and dyeing wastewater, and enters the biochemical wastewater treatment system of the factory;

The undissolved loose wool fiber aggregates are stripped and bleached to obtain recycled wool fibers with good strength and length.

Comparative Example 1

Example 1 was repeated except that in b, 100% NaOH 1.5g/L and penetrant 2g/L were added in a closed tank.

It can be clearly seen from Figure 2 and Figure 3 that when the solvent of the present invention is used for dissolution treatment, the dissolution rate is faster (that is, the digestion is faster), and the damage to the non-dissolving fiber is smaller (with a smaller figure). Shaded area), thus indicating that the solvent of the present invention has a fast dissolving speed for soluble fibers and a solvent with little damage to insoluble fibers, which means particularly favorable economic benefits and value.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples have structural elements that do not differ from the literal language of the claims, or if such other examples include equivalent structural elements with insubstantial differences from the literal language of the claims, such other examples are intended within the scope of the claims. To the extent that it does not create inconsistency, all citations referenced herein are incorporated herein by reference.

Claims (7)

1. A method of recycling a dissolvable textile, wherein the dissolvable textile comprises or is made from a controlled dissolving fibrous facing, the method comprising the steps of:

a. for controlled dissolving fibrous fabrics, the method comprises the steps of:

placing the controllable dissolving fiber fabric into a container, adding a solvent to completely dissolve the controllable dissolving fiber fabric, filtering, acid-separating and degassing a dissolving solution to obtain terephthalic acid and ethylene glycol, wherein the COD (chemical oxygen demand) of the discharged wastewater meets the environmental protection requirement;

or,

b. for a fibrous fabric having a blend or interweave of controlled dissolving fibers with other non-dissolving fibers, the method comprises the steps of:

placing the fiber fabric in a container, adding a solvent to dissolve the fiber fabric, filtering, acid-separating and degassing a dissolved solution to obtain terephthalic acid and ethylene glycol, wherein the COD (chemical oxygen demand) of the discharged wastewater meets the environmental protection requirement; cleaning and disinfecting the non-soluble fiber to obtain a loose fiber aggregate;

the solvent of the steps a and b comprises ionic liquid, the content of the ionic liquid is 0.1-10.0 wt% based on the total weight of the solvent, and the ionic liquid is the ionic liquid shown in the following formula (I):

the solvent in a or b comprises DMSO and tetrabutylammonium acetate, and the content of the DMSO in the solvent is 10-30 wt% and the content of the tetrabutylammonium acetate in the solvent is 0.1-5.0 wt% based on the total weight of the solvent.

2. The method according to claim 1, wherein the solvent further comprises ethanol.

3. The method according to claim 1, wherein the solvent in a or b is basic.

4. The method of claim 1, wherein the soluble textile is a soluble textile made by the method of:

(1) adding terephthalic acid, isophthalic acid, ethylene glycol and 5-sodium sulfonate-isophthalic acid polyethylene glycol ester, selecting different substance combinations and different proportions from the terephthalic acid, the isophthalic acid polyethylene glycol ester to polymerize to obtain slices, wherein the slices are alkali-soluble slices, and then sequentially carrying out tape casting, cooling, grain cutting and drying to obtain material particles;

(2) and spinning the material particles to prepare controllable dissolving fibers, and using the controllable dissolving fibers to prepare soluble textiles.

5. The process according to claim 4, wherein the spinning temperature is 270-300 ℃.

6. The process according to claim 5, wherein the spinning temperature is 280-290 ℃.

7. The method of claim 1, wherein the loose assembly of fibers is blended or interwoven with controlled dissolving fibers to produce a fibrous facing.

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