阅读说明：本技术 一种解聚含锦纶废聚酯制备共聚酯酰胺的方法 (Method for preparing copolyester amide by depolymerizing waste polyester containing chinlon ) 是由 王秀华 王勇 李新安 黄宜坤 郭静雯 李勇 于 2019-11-15 设计创作，主要内容包括：本申请涉及废聚酯、锦纶回收利用领域,尤其涉及一种解聚含锦纶废聚酯制备共聚酯酰胺的方法。该方法包括以下的步骤：1)将含锦纶废聚酯材料经预处理后,由热摩擦成型工艺制成泡料；2)泡料在螺杆挤出机中进行熔融再造粒,在螺杆挤出过程中同时加入物理或者化学发泡剂,制备成泡孔尺寸可控的含微孔粒料；3)先按比例将废聚酯与乙二醇一同加入到反应釜中在催化剂作用下进行聚酯解聚1-3小时,解聚完成后对解聚液进行过滤,滤液为含BHET和齐聚物；4)再将过滤出的锦纶投入至解聚釜中,补加乙二醇对滤锦纶继续解聚,从而得到含低分子量聚酰胺的解聚产物；5)步骤3)获得的滤液和步骤4)获得解聚产物送至缩聚釜中在缩聚催化剂和稳定剂作用下经预缩聚和终缩聚,最后制备出再生共聚酯酰胺。(The application relates to the field of recycling of waste polyester and nylon, in particular to a method for preparing copolyester amide by depolymerizing waste polyester containing nylon. The method comprises the following steps: 1) pretreating the waste polyester material containing the chinlon, and preparing the waste polyester material into a foam material by a thermal friction forming process; 2) melting and granulating the foam material in a screw extruder, and simultaneously adding a physical or chemical foaming agent in the screw extrusion process to prepare the micropore-containing granules with controllable cell sizes; 3) firstly, proportionally adding waste polyester and ethylene glycol into a reaction kettle together to carry out polyester depolymerization for 1-3 hours under the action of a catalyst, and filtering depolymerization liquid after depolymerization is finished, wherein the filtrate contains BHET and oligomers; 4) putting the filtered chinlon into a depolymerization kettle, adding ethylene glycol to continue depolymerization of the filtered chinlon, thereby obtaining a depolymerization product containing low molecular weight polyamide; 5) and (3) sending the filtrate obtained in the step 3) and the depolymerization product obtained in the step 4) to a polycondensation kettle for pre-polycondensation and final polycondensation under the action of a polycondensation catalyst and a stabilizer, and finally preparing the regenerated copolyesteramide.)

1. A method for preparing copolyester amide by depolymerizing waste polyester containing chinlon is characterized by comprising the following steps:

1) pretreating the waste polyester material containing the chinlon, and preparing the waste polyester material into a foam material by a thermal friction forming process;

2) melting and granulating the foam material in a screw extruder, and simultaneously adding a physical or chemical foaming agent in the process of double-screw extrusion to prepare microporous-containing granules with controllable cell sizes;

3) firstly, proportionally adding waste polyester and ethylene glycol into a reaction kettle together to carry out polyester depolymerization for 1-3 hours under the action of a catalyst, and filtering depolymerization liquid after depolymerization is finished, wherein the filtrate contains BHET and oligomers;

4) putting the filtered chinlon into a depolymerization kettle, adding ethylene glycol to continue depolymerization of the filtered chinlon, thereby obtaining a depolymerization product containing low molecular weight polyamide;

5) and (3) sending the filtrate obtained in the step 3) and the depolymerization product obtained in the step 4) to a polycondensation kettle for pre-polycondensation and final polycondensation under the action of a polycondensation catalyst and a stabilizer, and finally preparing the regenerated copolyesteramide.

2. The method for preparing the copolyesteramide by depolymerizing the waste polyamide polyester according to claim 1, wherein the waste polyamide polyester in the step 1) comprises one or more of polyester-nylon fabric, polyester-nylon composite yarn, polyester-nylon pulp block, waste polyester textile, polyamide textile, waste polyester yarn and waste polyamide yarn; preferably, the content of the chinlon in the waste polyester material containing the chinlon is 15 to 30 percent; preferably, the temperature of the hot friction forming process is 150-260 ℃, the pressure is 0.1-10 MPa, and the time is 5-15 min.

3. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester, according to claim 1, wherein the average cell diameter of the microporous granules in step 2) is 30-200 μm, and the relative density is 0.3-0.7.

4. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester according to claim 1, wherein the physical foaming agent in step 2) is one or more of nitrogen, carbon dioxide and inert gas, and the like, the physical foaming agent is introduced into a fourth heating zone of the screw, and after granulation, the micro-pores are stably formed after passing through a cooling water tank; the chemical foaming agent is one or a combination of more of foaming agent AC, foaming agent DPT, foaming agent ABIN, foaming agent OBSH and foaming agent NTA, and can be fed together at a feeding port or mixed in a fourth heating zone of the screw; preferably, the temperature of the screw extruder is 220-320 ℃, the feeding percentage is 5-15%, the rotating speed of the screw is 40-80rpm, and the pressure is 70-100 Mpa; preferably, the gas introduction amount is 0.05-0.3L/min, and the ratio of the foaming agent to the waste polyester material is 1: 100-500.

5. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester according to claim 1, wherein the screw pelletizer in step 2) is provided with a filtering device in front of the die head, and the filtering device is regulated to be 100-200 meshes; the filtering precision of the depolymerized liquid after the depolymerization in the step 4) is 150 meshes-300 meshes.

6. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester according to claim 1, wherein the depolymerization reaction in step 3) is carried out according to the repeating unit of waste polyamide: putting ethylene glycol into a depolymerization kettle according to the molar percentage of 1: 1-6, wherein the depolymerization kettle contains ethylene terephthalate and oligomers which account for 10-30% of the total amount of the waste polyester, and a depolymerization catalyst is added, and the depolymerization catalyst is one or more of acetates, preferably zinc acetate; controlling the depolymerization reaction temperature to be 190-210 ℃, the reaction time to be 30 minutes-5 hours and the pressure to be 0.1-0.3 Mpa; controlling the depolymerization reaction temperature to be 190-210 ℃, the pressure to be 0.05-0.5Mpa and the reaction time to be 30 minutes-5 hours to obtain the depolymerization product containing the ethylene terephthalate and the oligomer, and then filtering the depolymerization product by a filter with the precision of 150 meshes and 300 meshes.

7. The method for preparing copolyesteramide by depolymerizing waste polyamide-containing polyester according to claim 1, wherein the amount of ethylene glycol replenished in the depolymerization reaction of nylon of step 4) is determined according to the ratio of nylon: the mass ratio of the ethylene glycol is 1:3, the temperature is controlled to rise to 230 ℃ and 270 ℃, the pressure is 0.05-0.5Mpa, the reaction is continued for 30min-4 h, the partial depolymerization of the chinlon is carried out until the relative viscosity is 1.00-1.30, and the reaction is considered to be finished.

8. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester as set forth in claim 1, wherein the polycondensation reaction temperature in step 5) is 220-250 ℃ and the vacuum degree is 200-400Kpa, the temperature is maintained for 1-4 hours, the partial copolymerization is carried out, and then the temperature is continuously raised to 255-270 ℃ and the vacuum degree is 30-100Kpa, and the reaction time is 3-8 hours; the polycondensation catalyst is a titanium compound, preferably tetrabutyl titanate; the stabilizer is triphenyl phosphate, triphenyl phosphite, trimethyl phosphate, etc., preferably triphenyl phosphate.

9. The method for preparing copolyesteramide by depolymerizing waste polyamide polyester as set forth in claim 1, wherein the method further comprises, between step 2 and step 3), separating easily soluble impurities from the waste polyamide granules with micropores by using a dissolving agent; fully contacting and soaking the waste polyester granules containing micropores for 10-40min by using the dissolving agent at the temperature of 20-180 ℃, dissolving spandex and possibly existing soluble fibers except polyester, and then cleaning the waste polyester granules with purified water after solid-liquid separation; preferably, the dissolving agent is one or a combination of several components of dimethylacetamide, N-N dimethylformamide, dimethyl sulfoxide, diethyl ether, xylene, N-butanol, formic acid, m-cresol, triethylene glycol, tetrahydrofuran, 1-ethyl-3-methylimidazole bromine salt, trifluoroethanol, benzenediol, o-dichlorobenzene, cyclohexanone, cyclopentanone, acetone and N-methylpyrrolidone; and is preferably one or the combination of several of N-N dimethylformamide, dimethyl sulfoxide and formic acid.

10. The copolyesteramide prepared by the method according to any one of claims 1 to 9, wherein the final product of the copolyesteramide has the intrinsic viscosity of 0.7 to 0.9dL/g, the content of carboxyl end groups is less than 18mol/t, the melting point is 180 to 230 ℃, and the number of agglomerated particles is less than or equal to 1/mg.

Technical Field

The application relates to the field of recycling of waste polyester and nylon, in particular to a method for preparing copolyester amide by depolymerizing waste polyester containing nylon.

Background

Polyethylene terephthalate (PET) is a polymer of terephthalic acid or dimethyl terephthalate and ethylene glycol. Due to good physical and chemical stability, processability and the like, the composite material is widely applied to the fields of textile clothing, decoration, food packaging and the like. However, because PET has very strong chemical inertness under natural conditions and is difficult to biodegrade, and a large amount of waste polyester exerts a great pressure on the environment, recycling waste polyester products, realizing effective recycling of resources, and reducing environmental pollution become important subjects of the polyester industry. The most prominent advantage of polyamide fibers, also known as polyamide fibers, is superior wear resistance over other fibers and secondly good elasticity and elastic recovery comparable to wool and also a light weight specific gravity of 1.14 in a commercially available synthetic fiber, which has been found to be superior to polypropylene (which has been found to be specific gravity less than 1) and lighter than polyester fibers (which has been found to be specific gravity of 1.38), and thus polyamide fibers can be processed into thin, soft and smooth filaments for weaving into aesthetically pleasing fabrics and are corrosion resistant as well as polyester fibers.

At present, the recycling of polyester waste materials mainly comprises a physical method and a chemical method. The physical method is mainly to make the waste polyester and the products thereof into regenerated chips through the processes of cutting, crushing, mixing, granulating and the like, and then reuse the regenerated chips, but the quality fluctuation of the regenerated chips is large, so that the preparation and the quality of the fibers are greatly influenced. The chemical method is mainly to depolymerize the waste polyester into raw materials or intermediates for producing the polyester by a chemical treatment method, such as a hydrolysis method, a methanol alcoholysis method, an ethylene glycol alcoholysis method and the like, and obtain high-quality raw material monomers by the procedures of purification, impurity removal and the like. At present, the pretreatment of materials before depolymerization mainly comprises the following steps: the waste silk and waste textile are cut or sheared and put into a depolymerization kettle, for example, the method of the 'pretreatment system of waste fiber and products' disclosed in the publication No. CN 105690600A. However, the bulk density of the waste is low, so that the waste is not easy to be soaked by a solvent, the liquid-solid ratio is increased, and the energy consumption and the material consumption are increased. In addition, waste silk and waste textile are made into foam materials by a friction granulation method, and then are put into a depolymerization kettle for depolymerization, for example, the method of 'recycling process of waste textile containing polyester' disclosed in the publication No. CN 105803585A.

Publication No. CN108641120A discloses a method for recycling waste polyester textiles and a recycling system thereof, which are used for carrying out alcoholysis, filtration, refining and polycondensation on waste polyester by using ethylene glycol to obtain regenerated polyester. Because the waste polyester often contains a part of nylon, particularly the recycled polyester-nylon fabric and polyester-nylon composite yarn contain a large amount of nylon, and because the waste nylon can be partially alcoholyzed in ethylene glycol, the waste nylon cannot be removed by a filtering method, and the repolymerization process and the quality of regenerated products are influenced.

The second most of the prior synthetic fibers are widely applied to the aspects of textile clothing, packaging, automobile interior decoration and the like together with terylene, and face the dilemma of difficult natural decomposition with the terylene, and a part of the nylon is often mixed in the recovery process of waste polyester, so that a great amount of manpower and material resources are consumed for distinguishing the nylon. The polyamide also has depolymerization effect under the depolymerization condition of the waste polyester, but the polyamide content in the waste polyester is not fixed, so that the polyamide cannot be effectively utilized and is often filtered out as impurities.

Publication No. CN101906211B discloses "a polyester-polyamide copolymer and a method for synthesizing the same", which is to add nylon with relatively low viscosity in the polymerization process of polyester, and to make the polyester prepolymer and nylon 6 have copolymerization reaction, so as to prepare the polyester copolymer with amide groups. However, the present invention prepares copolyester amide through the reaction of pure PET material glycol terephthalate and nylon, and the present invention prepares copolyester amide through depolymerizing waste polyester into glycol terephthalate and copolymerizing with nylon.

Disclosure of Invention

In order to solve the problem that chinlon in the waste polyester cannot be effectively utilized, the application aims to provide the method for preparing the copolyester amide by depolymerizing the waste polyester containing chinlon.

In order to achieve the above object, the present application adopts the following technical solutions:

a method for preparing copolyester amide by depolymerizing waste polyester containing chinlon comprises the following steps:

1) pretreating the waste polyester material containing the chinlon, and preparing the waste polyester material into a foam material by a thermal friction forming process;

2) melting and granulating the foam material in a screw extruder, and simultaneously adding a physical or chemical foaming agent in the process of double-screw extrusion to prepare microporous-containing granules with controllable cell sizes;

3) firstly, proportionally adding waste polyester and ethylene glycol into a reaction kettle together to carry out polyester depolymerization for 1-3 hours under the action of a catalyst, and filtering depolymerization liquid after depolymerization is finished, wherein the filtrate contains BHET and oligomers;

4) putting the filtered chinlon into a depolymerization kettle, adding ethylene glycol to continue depolymerization of the filtered chinlon, thereby obtaining a depolymerization product containing low molecular weight polyamide;

5) and (3) sending the filtrate obtained in the step 3) and the depolymerization product obtained in the step 4) to a polycondensation kettle for pre-polycondensation and final polycondensation under the action of a polycondensation catalyst and a stabilizer, and finally preparing the regenerated copolyesteramide.

Preferably, the waste polyester containing nylon in the step 1) comprises one or more of polyester-nylon fabric, polyester-nylon composite yarn, polyester-nylon pulp block, waste polyester textile, waste nylon textile, waste polyester yarn and waste nylon yarn; preferably, the content of the chinlon in the waste polyester material containing the chinlon is 15 to 30 percent; preferably, the temperature of the hot friction forming process is 150-260 ℃, the pressure is 0.1-10 MPa, and the time is 5-15 min.

Preferably, the pretreatment comprises cleaning, sorting and cutting of polyester-nylon fabrics (carpets and curtains), polyester-nylon composite yarns, waste Polyester (PET) textiles (curtains, clothing and the like), nylon textiles (clothing, towels and the like), waste polyester yarns and waste nylon yarns; mixing waste Polyester (PET) textiles (curtains, clothes and the like), nylon textiles (clothes, towels and the like), waste polyester yarns and waste nylon yarns; and (5) carrying out smashing treatment on the polyester-nylon pulp blocks and the like.

Preferably, the microporous pellets of step 2) have an average cell diameter of 30 to 200 μm and a relative density of 0.3 to 0.7.

Preferably, the physical foaming agent in the step 2) is one or a combination of nitrogen, carbon dioxide, inert gas and the like, the physical foaming agent is introduced into a fourth heating zone of the screw, and after granulation is finished, the physical foaming agent passes through a cooling water tank and then the micropores are stably formed; (ii) a The chemical foaming agent comprises one or more combinations of foaming agent AC (azodicarbonamide), foaming agent DPT (N, N-dinitrosopentamethylenetetramine), foaming agent ABIN, foaming agent OBSH (4, 4-disulfonylhydrazide diphenyl ether), foaming agent NTA (N, N-dimethyl-N, N-diterephthalamide) and the like, and the chemical foaming agent can be fed together at a feeding port or mixed in a fourth heating zone of the screw; preferably, the temperature of the screw extruder is 220-320 ℃, the feeding percentage is 5-15%, the rotating speed of the screw is 40-80rpm, and the pressure is 70-100 Mpa; preferably, the gas introduction amount is 0.05-0.3L/min, and the ratio of the foaming agent to the waste polyester material is 1: 100-500.

Preferably, the screw granulator in the step 2) is added with a filtering device in front of the die head, and the filtering device is regulated to be 100-200 meshes; the filtering precision of the depolymerized liquid after the depolymerization in the step 4) is 150 meshes-300 meshes.

Preferably, the depolymerization reaction of step 3) is carried out as a waste polyester (meaning a repeating unit, the same applies below): putting ethylene glycol into a depolymerization kettle according to a molar ratio of 1: 1-9 (mass ratio of 1: 0.33-3), wherein the depolymerization kettle contains ethylene terephthalate and oligomers which account for 10-30% by mass of the total amount of the waste polyester, and a depolymerization catalyst is added, and the depolymerization catalyst is one or more of acetates, preferably zinc acetate; controlling the depolymerization reaction temperature to be 190-210 ℃, the reaction time to be 30 minutes-5 hours and the pressure to be 0.1-0.3 Mpa; controlling the depolymerization reaction temperature to be 190-210 ℃, the pressure to be 0.05-0.5Mpa and the reaction time to be 30 minutes-5 hours to obtain the depolymerization product containing the ethylene terephthalate and the oligomer, and then filtering the depolymerization product by a filter with the precision of 150 meshes and 300 meshes.

Preferably, the amount of the supplemental ethylene glycol in the depolymerization reaction of the chinlon in the step 4) is determined according to the ratio of the amount of the supplemental ethylene glycol in the chinlon: the mass ratio of the ethylene glycol is 1:3, the temperature is controlled to rise to 230 ℃ and 270 ℃, the pressure is 0.05-0.5Mpa, the reaction is continued for 30min-4 h, the partial depolymerization of the chinlon is carried out until the relative viscosity is 1.00-1.30, and the reaction is considered to be finished.

Preferably, the polycondensation reaction temperature in the step 5) is 220-250 ℃ and the vacuum degree is 200-400Kpa, the polymerization is maintained for 1-4 hours, partial copolymerization is carried out, then the temperature is continuously raised to 255-270 ℃, the vacuum degree is 30-100Kpa, and the reaction time is 3-8 hours; the polycondensation catalyst is a titanium compound, preferably tetrabutyl titanate; the stabilizer is triphenyl phosphate, triphenyl phosphite, trimethyl phosphate, etc., preferably triphenyl phosphate.

Preferably, the method also comprises the step of separating the easily soluble impurities from the waste polyester granules containing micropores by using a dissolving agent between the step 2 and the step 3); fully contacting and soaking the waste polyester granules containing micropores for 10-40min by using the dissolving agent at the temperature of 20-180 ℃, dissolving spandex and possibly existing soluble fibers except polyester, and then cleaning the waste polyester granules with purified water after solid-liquid separation; preferably, the dissolving agent is one or a combination of several components of dimethylacetamide, N-N dimethylformamide, dimethyl sulfoxide, diethyl ether, xylene, N-butanol, formic acid, m-cresol, triethylene glycol, tetrahydrofuran, 1-ethyl-3-methylimidazole bromine salt, trifluoroethanol, benzenediol, o-dichlorobenzene, cyclohexanone, cyclopentanone, acetone and N-methylpyrrolidone; and is preferably one or the combination of several of N-N dimethylformamide, dimethyl sulfoxide and formic acid.

The application also discloses the copolyesteramide prepared by the method, wherein the intrinsic viscosity of the finished product of the copolyesteramide is 0.7-0.9dL/g, the content of terminal carboxyl groups is less than 18mol/t, the melting point is 180-230 ℃, and the number of agglutinated particles is less than or equal to 1/mg.

Further, the application also discloses that the waste polyester depolymerization liquid obtained in the step 4) is subjected to precipitation adsorption treatment and magnetic fluid sedimentation treatment to obtain the high-purity waste polyester depolymerization liquid, and the application introduces the whole contents of Chinese patent application numbers 2019110064695, 2019110065132 and 2019110065113.

Preferably, the precipitating agent for precipitation and impurity removal comprises the following components:

4-12 parts of nano calcium oxide

2-10 parts of diatomite

5-15 parts of nano aluminum oxide

1-6 parts of potassium hydroxide

2-10 parts of calcium carbonate

1-5 parts of hydroxyethyl cellulose sodium

2-10 parts of polyacrylamide.

As a further preference, the precipitant consists of:

6-8 parts of nano calcium oxide

3-5 parts of diatomite

8-10 parts of nano aluminum oxide

2-4 parts of potassium hydroxide

4-6 parts of calcium carbonate

2-3 parts of hydroxyethyl cellulose sodium

3-4 parts of polyacrylamide.

The application also discloses a preparation method of the precipitator, which comprises the steps of adding nano calcium oxide, diatomite, nano aluminum oxide, calcium carbonate, hydroxyethyl cellulose sodium and polyacrylamide into a grinder for grinding, sieving by a 100-mesh sieve, adding potassium hydroxide, mixing, adding into a stirring kettle for fully stirring at a stirring speed of 600 revolutions per minute for 50 minutes, and thus obtaining the precipitator.

As a further improvement, the impurity removal method also comprises the steps of removing impurities by magnetic fluid adsorption, precipitating and then continuously putting the filtrate into a magnetic fluid impurity remover to enable F to be in a state ofeO mixing the magnetic fluid and the filtrate in the trash separator, disconnecting the magnetic base of the trash separator to make it become permanent magnetic field, after 10-20 minutes, the magnetic particles are deposited downwards and layered, and then filtering to remove nylon, spandex, delustering agent, titanium dioxide, etc.; preferably, the FeO magnetofluid is prepared by adopting an alcohol-water co-heating method according to Fe³⁺And Fe²⁺Fe in a molar ratio of 1-3:1₂(SO₄)₃Solution and FeSO₄Mixing the solutions, heating to 60-70 deg.C, maintaining constant temperature, adding NaOH solution dropwise, stirring thoroughly to adjust pH to 10-12, stirring and adding anhydrous ethanol, standing for 20-30 min, adjusting pH, increasing temperature, stirring rapidly and adding 0.4-0.8 times of Fe²⁺The coating was carried out with the amount of sodium oleate surfactant, and then the formation of black magnetic particles was observed.

The invention has the beneficial effects that: 1) The waste polyester material is depolymerized and regenerated and polyamide is used for preparing the copolyester amide, so that the polyester waste and the polyamide waste are reasonably utilized; 2) the copolyester amide prepared from the waste polyester and the chinlon has the advantages of high tensile strength, high elongation at break, uniform dyeing and the like; 3) the waste polyester material is foamed, so that the depolymerization reaction can be effectively accelerated, and the cost is reduced; 4) the preparation of the copolyester amide can be realized by simply regulating and controlling the original polyester depolymerization regeneration process, and the industrial production is easy to carry out; 5) a certain amount of mother liquor is remained in the alcoholysis kettle, which can improve the depolymerization efficiency and stabilize the quality of depolymerization products.

Detailed description of the invention

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.