Recovery method of sea material in sea-island fiber
阅读说明：本技术 一种海岛纤维中海材料的回收方法 (Recovery method of sea material in sea-island fiber ) 是由 付昌飞 李赛 解德诚 邢亚均 石浩然 顾进 魏怡雯 薛丽云 曹伟新 钱桢英 崔厚 于 2020-07-07 设计创作，主要内容包括：本发明提供一种海岛纤维中海材料的回收方法,所述海岛纤维经开纤后,海材料溶解于含有溶胀剂和助溶剂的水溶液中；对溶解有海材料的含有溶胀剂和助溶剂的水溶液加水稀释后,改性共聚酯以絮状沉淀形式从溶液中析出,经固液分离获得回收的海材料。本申请中的海材料改性共聚酯既可以在温和条件下溶解,又可以通过简单的手段回收,实现循环利用,节约了资源。(The invention provides a recovery method of sea material in sea-island fiber, after the sea-island fiber is opened, the sea material is dissolved in water solution containing swelling agent and cosolvent; after the water solution containing the swelling agent and the cosolvent, in which the sea material is dissolved, is diluted by adding water, the modified copolyester is separated out from the solution in the form of flocculent precipitates, and the recovered sea material is obtained through solid-liquid separation. The sea material modified copolyester can be dissolved under mild conditions, and can be recycled by simple means, so that the cyclic utilization is realized, and the resources are saved.)
1. A method for recovering sea material in sea-island fiber is characterized in that after the sea-island fiber is opened, the sea material is dissolved in water solution containing swelling agent and cosolvent; after the water solution containing the swelling agent and the cosolvent, in which the sea material is dissolved, is diluted by adding water, the modified copolyester is separated out from the solution in the form of flocculent precipitates, and the recovered sea material is obtained through solid-liquid separation.
2. The recycling method according to claim 1, wherein the sea material in the sea-island fiber is a modified copolyester having a structural formula shown as follows:
wherein the repeating unit
3. The recovery method according to claim 1, wherein the water is added to dilute the mixture until the content of the swelling agent is not more than 5 wt%; and/or diluting with water until the content of cosolvent is not more than 2 wt%; and/or after the solid-liquid separation, washing and drying the solid sea material.
4. The recycling method according to claim 1, wherein, in the modified copolyester,the number of repetitions of the structure is less than 3.
5. The recycling method according to claim 1, wherein in the modified copolyester, structure
6. The recovery process of claim 1, wherein the intrinsic viscosity of the modified copolyester is (0.4 to 0.7) dL/g;
and/or the melting point of the modified copolyester is 200-240 ℃.
7. The recycling method according to claim 1, wherein the modified polyester is prepared by a method comprising:
1) carrying out esterification reaction on ethylene glycol and terephthalic acid;
2) adding m-benzene dibasic acid dibasic ester-5-sodium sulfonate or m-benzene dibasic acid dibasic ester-5-potassium sulfonate, and adding 2-methyl-1, 3-propylene glycol and 1, 3-propylene glycol for ester exchange;
3) adding catalyst and heat stabilizer to perform polycondensation reaction.
8. The recovery method according to claim 7, wherein the temperature of the esterification reaction is 240 to 270 ℃;
and/or the esterification reaction time is 2-4 h;
and/or the temperature of the ester exchange reaction is 240-270 ℃;
and/or the ester exchange reaction time is 1-3 h;
and/or the temperature of the polycondensation reaction is 270-300 ℃;
and/or the time of the polycondensation reaction is 2-4 h;
and/or the catalyst is one or more of Zn, Sb, Mn, Ca or Co-containing compounds;
and/or the addition amount of the catalyst is not more than 0.08 percent of the mass of the terephthalic acid;
and/or the heat stabilizer is trimethyl phosphate or triphenyl phosphate;
and/or the addition amount of the heat stabilizer is 0.02-0.06% of the mass of the terephthalic acid.
9. The recovery method according to claim 1, wherein the sea-island fiber is obtained by opening sea material by: and (3) splitting the sea-island fiber in water containing a swelling agent and a cosolvent.
10. The recovery method according to claim 9, wherein the temperature of the water is 30 to 60 ℃ during the fiber opening treatment;
and/or the content of the swelling agent in the water is 5-25 wt%;
and/or the content of the cosolvent in the water is 2-20 wt%;
and/or the swelling agent is one or more selected from sulfolane, urea, isopropanol, glycol, polyoxyethylene and polyvinylpyrrolidone;
and/or the cosolvent is selected from NH4+、K+、Na+、Ca2+、Zn2+、Mg2+And Al3+Is one or more of soluble salts of (A), the anion of the soluble salt is SO4 2-、CO3 2-、NO3-、Ac-And Cl-One or more of (a).
Technical Field
The invention relates to the field of fiber material treatment, in particular to a method for recovering sea materials in sea-island fibers.
Background
The sea-island fiber is a short for sea-island composite fiber, and is prepared by melt spinning 2 fiber-forming polymers respectively as island component and sea component in different proportions by composite spinning technology, and removing sea component and leaving island component to obtain superfine fiber by utilizing different solubility or decomposability of the 2 components to certain chemical solvents. The sea-island fiber is classified into a hydrolysis-peeling type (alkali weight reduction method), a solvent-dissolving type (benzene weight reduction method), and a hot-water dissolving type (hot-water dissolving method) according to the type of sea-phase polymer and the opening process.
The hydrolysis stripping type (alkali reduction method) adopts alkali soluble polyester (COPET) as a sea component of sea-island fibers, adopts the conditions of high temperature and strong alkali (the temperature is more than or equal to 95 ℃ and the pH value is more than or equal to 13) to degrade the sea-phase COPET into sodium terephthalate and ethylene glycol, has various problems of recycling of hydrolysate, treatment of waste alkali liquor and the like, has difficult treatment of alkali reduction waste liquor with strong alkalinity, and has high pollution discharge cost.
The solvent sea-dissolving type (benzene reduction method) adopts low-density polyethylene (LDPE) as a sea component of sea-island fibers, and adopts organic solvents such as toluene or xylene to dissolve the sea-phase LDPE at a higher temperature (the temperature is more than or equal to 85 ℃), so that the leakage risk of toxic harmful solvents and the residue problem of trace toxic harmful solvents on superfine fibers exist, the recovered LDPE has toxic harmful organic solvents such as toluene or xylene, and the use value is reduced.
The hot water dissolving type (hot water dissolving method) is disclosed in CN108589028A, CN108589028A, CN108505190A, CN108589028A, CN108486683A and CN108424601A, polyvinyl alcohol (PVA) is used as the sea phase of the sea-island fiber, if the island component is PET, the problem that the spinning temperature difference of the two phases of the sea-island is large (the temperature difference is more than 80 ℃) and the spinning on common sea-island spinning equipment is difficult exists, and the existence of water needs to be avoided in the drawing post-processing and application processes before fiber opening, otherwise, the fiber can generate the bonding phenomenon, and the service performance of the fiber is seriously influenced. The polyvinyl alcohol aqueous solution after opening is low in recycling value, and if the polyvinyl alcohol aqueous solution is directly discharged, the waste of resources is caused. In addition, the PVA sea component disclosed in the above patent contains additives such as a polyol or salt compound modifier, an antioxidant, a lubricant, and the like (the total content of which accounts for at least 15% of the sea component), which all increase the difficulty and cost of the treatment of the opening waste water.
In summary, the methods for opening sea-island fibers available in the market in mass production all have certain defects and are accompanied with irreversible environmental pollution. At present, no sea component exists, which can realize value retention or high added value recycling, has no toxicity or zero emission in the recycling process, and can be well matched with various spinning sea components such as high polymer PET, PA6, PP and the like.
Disclosure of Invention
In view of the above-mentioned disadvantages of the prior art, it is an object of the present invention to provide a method for recovering sea material in an island fiber, which solves the problems of resource waste and environmental pollution occurring when preparing a microfiber by an island fiber in the prior art.
To achieve the above objects and other related objects, the present invention is achieved by the following technical solutions.
The invention provides a recovery method of sea material in sea-island fiber, after the sea-island fiber is opened, the sea material is dissolved in water solution containing swelling agent and cosolvent; after the water solution containing the swelling agent and the cosolvent, in which the sea material is dissolved, is diluted by adding water, the modified copolyester is separated out from the solution in the form of flocculent precipitates, and the recovered sea material is obtained through solid-liquid separation.
According to the recovery method, the sea material in the sea-island fiber is modified copolyester, and the structural formula of the modified copolyester is shown as the following formula:
wherein the repeating unitIs randomly selected from
According to the above recovery method, water is added to dilute until the content of the swelling agent is not more than 5 wt%.
According to the recovery method, water is added for dilution until the content of the cosolvent is not more than 2 wt%.
According to the above recovery method, the step of washing and drying the solid sea material is further included after the solid-liquid separation.
According to the above-mentioned recycling method, in the modified copolyester,
In the recycling method, the structure of the modified copolyester
According to the recovery method, the intrinsic viscosity of the modified copolyester is 0.4-0.7 dL/g. Intrinsic viscosity in this application is measured by capillary viscometry.
According to the recovery method, the melting point of the modified copolyester is 200-240 ℃.
According to the above recycling method, the modified polyester is prepared by a method comprising:
1) carrying out esterification reaction on ethylene glycol and terephthalic acid;
2) adding m-benzene dibasic acid dibasic ester-5-sodium sulfonate or m-benzene dibasic acid dibasic ester-5-potassium sulfonate, and adding 2-methyl-1, 3-propylene glycol and 1, 3-propylene glycol for ester exchange;
3) adding catalyst and heat stabilizer to perform polycondensation reaction.
According to the recovery method, in the step 1), the temperature of the esterification reaction is 240-270 ℃.
According to the recovery method, in the step 1), the esterification reaction time is 2-4 h.
According to the recovery method, in the step 2), the temperature of the ester exchange reaction is 240-270 ℃.
According to the recovery method, in the step 2), the time of the ester exchange reaction is 1-3 h.
According to the recovery method, in the step 3), the temperature of the polycondensation reaction is 270-300 ℃.
According to the recovery method, in the step 3), the time of the polycondensation reaction is 2-4 h.
According to the recovery method, in the step 3), the catalyst is one or more of compounds containing Zn, Sb, Mn, Ca or Co.
According to the above recovery method, more preferably, in the step 3), the catalyst is antimony trioxide.
According to the recovery method, the adding amount of the catalyst is not more than 0.08 percent of the mass of the terephthalic acid, and is preferably 0.01 to 0.08 percent.
According to the above recycling method, in step 3), the heat stabilizer is trimethyl phosphate or triphenyl phosphate.
According to the recovery method, the addition amount of the heat stabilizer is 0.02-0.06% of the mass of the terephthalic acid.
According to the recovery method, the molar ratio of terephthalic acid, ethylene glycol, m-phthalic acid dibasic ester-5-sodium sulfonate or potassium, 2-methyl-1, 3-propanediol and 1, 3-propanediol is 1: (1.1-2.4): (0.015 to 0.07): (0.04-0.20): (0.02-0.10).
According to the recovery method, the sea-island fiber taking the modified copolyester as the sea component and other materials as the island component is obtained by adopting a composite spinning technology.
The composite spinning technology in the application adopts a melt composite spinning technology, a single island component material (such as PE, PP, PET or PA6 and other polymer materials capable of being melt-spun) is fed into a first screw extruder to be melted, meanwhile, the modified copolyester is fed into a second screw extruder to be melted as a sea component, the sea component is fed into a spinning manifold to be melted and extruded, the temperature of the spinning manifold is 265-285 ℃, and the difference of the melt temperature between the sea component material and the island component material is controlled to be 5-20 ℃; the island component is accurately metered by a metering pump and then is sent into the sea-island fiber composite component, and the island component is uniformly distributed into the sea component through a distribution pipeline in the sea-island fiber composite component and is sprayed out from the same spinneret orifice.
The recovery method of the sea-island fiber, the opening method of the sea material comprises the following steps: and (3) splitting the sea-island fiber in water containing a swelling agent and a cosolvent.
According to the recovery method, the temperature of the water is 60-70 ℃ during fiber opening.
According to the recovery method, the content of the swelling agent in the water is 5-25 wt%.
According to the recovery method, the content of the cosolvent in the water is 2-20 wt%.
The recovery method as described above, wherein the cosolvent is selected from NH4+、K+、Na+、Ca2+、Zn2+、Mg2+And Al3+Is one or more of soluble salts of (A), the anion of the soluble salt is SO4 2-、CO3 2-、NO3-、Ac-And Cl-One or more of (a).
The recovery method according to the above, wherein the swelling agent is one or more selected from sulfolane, urea, isopropanol, ethylene glycol, polyoxyethylene, and polyvinylpyrrolidone. Preferably, the polyoxyethylene is PEG 200. Preferably, the polyvinylpyrrolidone is PVP-K30.
According to the recycling method described above, the other material is selected from one or more of PET, PE, PP or PA 6.
According to the recovery method, the mass ratio of the sea component to the island component is 1: (1-9).
The beneficial effects of the above technical scheme in this application are:
the sea material modified copolyester can be dissolved in hot water solution of swelling agent and cosolvent with certain concentration, the swelling agent and the cosolvent in water are reduced to certain concentration, the water solution can be separated out from the solution in a flocculent precipitation form when the temperature is reduced to room temperature, and the viscosity change of the separated product is very small through testing, which indicates that the modified copolyester is not degraded but can be dissolved under a mild condition and recovered through a simple means in the process, so that the high molecular cycle utilization of the full-water system environment is realized, the sea material modified copolyester is non-toxic and harmless, zero emission is realized theoretically, and resources are saved.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
It is to be understood that the processing equipment or apparatus not specifically identified in the following examples is conventional in the art.
Furthermore, it is to be understood that one or more method steps mentioned in the present invention does not exclude that other method steps may also be present before or after the combined steps or that other method steps may also be inserted between these explicitly mentioned steps, unless otherwise indicated; it is also to be understood that a combined connection between one or more devices/apparatus as referred to in the present application does not exclude that further devices/apparatus may be present before or after the combined device/apparatus or that further devices/apparatus may be interposed between two devices/apparatus explicitly referred to, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.
The structural formula of the modified copolyester used in the examples of the present application is shown as follows:
wherein the content of the first and second substances,
repeating unitIs randomly selected from
M is potassium or sodium, and n is more than or equal to 95.
More specifically, in the modified copolyester,the number of consecutive repetitions of the structure is less than 3. Otherwise, the formed modified copolyester is intensified due to the ionic aggregation effect, the apparent viscosity is increased in a molten state, and the spinnability is reduced.
More specifically, the intrinsic viscosity of the modified copolyester is 0.4-0.7 dL/g. Intrinsic viscosity in this application is measured by capillary viscometry.
More specifically, the melting point of the modified copolyester is 200-240 ℃.
More specifically, the preparation method of the modified polyester comprises the following steps:
1) carrying out esterification reaction on ethylene glycol and terephthalic acid; the temperature of the esterification reaction is 240-270 ℃; the esterification reaction time is 2-4 h;
2) adding m-benzene dibasic acid dibasic ester-5-sodium sulfonate or m-benzene dibasic acid dibasic ester-5-potassium sulfonate, and adding 2-methyl-1, 3-propylene glycol and 1, 3-propylene glycol for ester exchange; the temperature of the ester exchange reaction is 240-270 ℃; the time of the ester exchange reaction is 1-3 h;
3) adding a catalyst and a heat stabilizer to perform polycondensation reaction; the temperature of the polycondensation reaction is 270-300 ℃; the time of the polycondensation reaction is 2-4 h; wherein the catalyst is antimony trioxide; the heat stabilizer is trimethyl phosphate or triphenyl phosphate.
And discharging the modified copolyester obtained through the reaction, granulating and drying to obtain the modified copolyester slice.
The modified copolyester according to the present application can be formed into the structure as described above by the molar ratio of the raw materials and the reaction temperature. Specifically, the molar ratio of terephthalic acid, ethylene glycol, m-phthalic acid dibasic ester-5-sodium sulfonate or potassium, 2-methyl-1, 3-propanediol and 1, 3-propanediol is 1: (1.1-2.4): (0.015 to 0.07): (0.04-0.20): (0.02-0.10).
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