阅读说明：本技术 一种解聚废聚酯在线添加锦纶制备共聚酯酰胺的方法 (Method for preparing copolyester amide by online adding polyamide to depolymerized waste polyester ) 是由 钱军 杜国强 马哲峰 钱仁飞 邢喜全 王秀华 王勇 于 2019-11-15 设计创作，主要内容包括：本申请属于废聚酯回收利用领域,尤其涉及一种解聚废聚酯在线添加锦纶制备共聚酯酰胺的方法。该方法包括以下的步骤：1)将回收分类的聚酯分类；2)然后在螺杆挤出机中进行熔融造粒,在造粒过程中通入物理或者化学发泡剂,通过冷却水槽后在废聚酯颗粒表面及内部形成微型孔洞；3)将此含微孔的废聚酯粒料先利用溶解剂分离出其中的易溶杂质；4)再按比例和乙二醇在催化剂作用下进行解聚,过滤制得高纯度的废聚酯解聚液；5)最后将解聚物送至缩聚釜中,加入相对粘度为1.0-1.8的锦纶和共聚催化剂和稳定剂进行低真空共聚反应1-4小时,然后转至高真空进行最后的缩聚制备聚酯酰胺共聚物。该方法最后制得再生共聚酯酰胺,实现废聚酯的高值化回收利用。(The application belongs to the field of waste polyester recycling, and particularly relates to a method for preparing copolyesteramide by depolymerizing waste polyester and adding chinlon on line. The method comprises the following steps: 1) sorting the recycled sorted polyester; 2) then carrying out melt granulation in a screw extruder, introducing a physical or chemical foaming agent in the granulation process, and forming micro holes on the surface and in the waste polyester particles after passing through a cooling water tank; 3) firstly, utilizing a dissolving agent to separate out soluble impurities from the waste polyester granules containing micropores; 4) then depolymerizing the mixture and glycol in proportion under the action of a catalyst, and filtering to obtain high-purity waste polyester depolymerization liquid; 5) and finally, sending the depolymerization product to a polycondensation kettle, adding chinlon with the relative viscosity of 1.0-1.8, a copolymerization catalyst and a stabilizer to perform low-vacuum copolymerization for 1-4 hours, and then turning to high vacuum to perform final polycondensation to prepare the polyesteramide copolymer. The method finally prepares the regenerated copolyester amide, and realizes high-valued recycling of the waste polyester.)

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

1) sorting the recycled sorted polyester;

2) then carrying out melt granulation in a screw extruder, introducing a physical or chemical foaming agent in the granulation process, and forming micro holes on the surface and in the waste polyester particles after passing through a cooling water tank;

3) firstly, utilizing a dissolving agent to separate out soluble impurities from the waste polyester granules containing micropores;

4) then depolymerizing the mixture and glycol in proportion under the action of a catalyst, and filtering to obtain high-purity waste polyester depolymerization liquid;

5) and finally, sending the depolymerization product to a polycondensation kettle, adding chinlon with the relative viscosity of 1.0-1.8, a copolymerization catalyst and a stabilizer to perform low-vacuum copolymerization for 1-4 hours, and then turning to high vacuum to perform final polycondensation to prepare the polyesteramide copolymer.

2. The method for preparing copolyesteramide by on-line adding of chinlon to depolymerized waste polyester according to claim 1, wherein the recycled classified polyester comprises one or more of recycled polyester bottle chips, polyester pulp blocks, polyester fiber products and polyester waste silk; wherein: firstly, carrying out densification treatment on a polyester film or a polyester fiber product through a hot friction forming process to prepare a foam material; 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; the polyester bottle flakes or polyester pulp blocks do not need to be made into foam materials, and the foam materials are cleaned and dried.

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

4. The method for preparing copolyesteramide by online adding polyamide to depolymerized waste polyester according to claim 1, wherein the physical foaming agent in step 2) is one or more of nitrogen, carbon dioxide and inert gas; 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; 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 online adding polyamide to depolymerized waste polyester according to claim 1, wherein the screw granulator in step 2) is provided with a filtering device in front of the die head, and the filtering device is regulated to be 200 meshes in 100 meshes; the filtering precision of the depolymerized liquid after the depolymerization in the step 4) is 100 meshes-200 meshes.

6. The method for preparing copolyesteramide by on-line adding polyamide to depolymerized waste polyester according to claim 1, wherein in step 3), the waste polyester granules containing micropores are fully contacted and dipped for 10-40min by the dissolver at the temperature of 20-180 ℃, spandex, polyamide and soluble fibers except polyester which may exist in the waste polyester granules are dissolved, and then the waste polyester granules are cleaned by 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.

7. The method for preparing copolyesteramide by online adding of chinlon to depolymerized waste polyester according to claim 1, wherein the depolymerization catalyst in step 4) is one or more of acetates, preferably zinc acetate; the copolymerization catalyst in the step 5) is one or more of a titanium compound and an antimony compound, and tetrabutyl titanate is preferred; the stabilizer is one or more of triphenyl phosphate, phosphorous acid and trimethyl phosphate, and triphenyl phosphate is preferred.

8. The method for preparing copolyesteramide by online adding of chinlon to depolymerized waste polyester according to claim 1, wherein the depolymerization reaction in the step 4) is carried out according to the repeating unit of waste polyester: putting the 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% by mass of the total amount of the waste polyester, and a depolymerization catalyst is added; 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; multistage filtration is arranged between the polycondensation kettles of the depolymerization kettles, and the filtration precision is sequentially improved; obtain the depolymerization product containing the glycol terephthalate and the oligomer.

9. The method for preparing copolyesteramide by online adding of nylon to depolymerized waste polyester as claimed in claim 1, wherein the nylon in step 5) is one or more of PA6, PA11, PA12, PA66 and PA1010, the viscosity is 1.0-1.8, the preferable amount of nylon is 10-30% of the mass fraction of the waste polyester, the preferable copolymerization comprises two steps of ① low vacuum of 200 and 240 Kpa, the reaction temperature is 220 and 240 ℃, the reaction time is 1-4 hours, ② high vacuum of 30-100Kpa, the reaction temperature is 255 and 290 ℃, and the reaction time is 3-8 hours.

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 of less than 20mol/t, the melting point of 180 to 250 ℃ and the number of agglomerated particles of less than or equal to 5/mg.

Technical Field

The application belongs to the field of waste polyester recycling, and particularly relates to a method for preparing copolyesteramide by depolymerizing waste polyester and adding chinlon on line.

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.

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.

Publication No. CN106113319A discloses a 'polyester-containing waste textile recycling and regenerating process', which comprises the steps of carrying out alcoholysis, esterification, polycondensation and multi-stage filtration on treated polyester waste in an alcoholysis kettle by using ethylene glycol to obtain regenerated polyester. 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. 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.

At present, the preparation of the copolyester amide mostly adopts the reaction of pure PET raw materials of ethylene glycol terephthalate and nylon, but the invention creatively uses waste polyester to firstly depolymerize into the ethylene glycol terephthalate, and then to copolymerize with the nylon to prepare the copolyester amide, which is the functional utilization of the waste polyester.

Disclosure of Invention

In order to solve the technical problems, the application aims to provide a method for preparing copolyesteramide by online adding polyamide to depolymerized waste polyester, and the method comprises the step of carrying out depolymerization reaction on the prepared microporous polyamide-containing waste polyester and ethylene glycol in proportion under the action of a catalyst to obtain a depolymerization product containing ethylene terephthalate (BHET) and oligomers. And finally, sending the depolymerization product to a polycondensation kettle, carrying out copolymerization and polycondensation by adding chinlon on line, and finally preparing the regenerated copolyesteramide to realize high-valued recycling of the waste polyester.

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 and adding chinlon on line comprises the following steps:

1) sorting the recycled sorted polyester;

2) then carrying out melt granulation in a screw extruder, introducing a physical or chemical foaming agent in the granulation process, and forming micro holes on the surface and in the waste polyester particles after passing through a cooling water tank;

3) firstly, utilizing a dissolving agent to separate out soluble impurities from the waste polyester granules containing micropores;

4) then depolymerizing the mixture and glycol in proportion under the action of a catalyst, and filtering to obtain high-purity waste polyester depolymerization liquid;

5) and finally, sending the depolymerization product to a polycondensation kettle, adding chinlon with the relative viscosity of 1.0-1.8, a copolymerization catalyst and a stabilizer to perform low-vacuum copolymerization for 1-4 hours, and then turning to high vacuum to perform final polycondensation to prepare the polyesteramide copolymer.

Preferably, the recycled classified polyester includes one or more of recycled polyester bottle chips, polyester pulp, polyester fiber products and polyester waste filaments; wherein: firstly, carrying out densification treatment on a polyester film or a polyester fiber product through a hot friction forming process to prepare a foam material; 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; the polyester bottle flakes or polyester pulp blocks do not need to be made into foam materials, and the foam materials are cleaned and dried.

Preferably, the waste polyester pellets obtained in step 2) containing the fine pores 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 more of nitrogen, carbon dioxide, inert gas and the like; 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; 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 100 meshes-200 meshes.

Preferably, the step 3) fully contacts and soaks the waste polyester granules containing micropores for 10-40min by the dissolvent with the temperature of 20-180 ℃, dissolves spandex, chinlon and possibly soluble fibers except polyester in the waste polyester granules, and then carries out purified water cleaning on the waste polyester granules 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.

Preferably, the depolymerization catalyst in the step 4) is one or more of acetates, preferably zinc acetate; the copolymerization catalyst in the step 5) is one or more of a titanium compound and an antimony compound, and tetrabutyl titanate is preferred; the stabilizer is one or more of triphenyl phosphate, phosphorous acid and trimethyl phosphate, and triphenyl phosphate is preferred.

Preferably, the depolymerization reaction in step 4) is carried out according to the ratio of waste polyester repeating units: putting the 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% by mass of the total amount of the waste polyester, and a depolymerization catalyst is added; 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; multistage filtration is arranged between the polycondensation kettles of the depolymerization kettles, and the filtration precision is sequentially improved; obtain the depolymerization product containing the glycol terephthalate and the oligomer.

Preferably, the chinlon in the step 5) is one or more of PA6, PA11, PA12, PA66 and PA1010, the viscosity is 1.0-1.8, the adding amount of the chinlon is preferably 10-30% of the mass fraction of the waste polyester, and the copolymerization comprises two steps, preferably, the low vacuum of ① and the low vacuum of 200 Kpa are adopted, the reaction temperature is 220 and 240 ℃, the reaction time is 1-4 hours, the high vacuum of ② and the high vacuum of 30-100Kpa are adopted, the reaction temperature is 255 and 290 ℃, and the reaction time is 3-8 hours.

The application also discloses the copolyesteramide prepared by the method, wherein the finished product of the copolyesteramide has the intrinsic viscosity of 0.7-0.9dL/g, the content of terminal carboxyl groups is less than 20mol/t, the melting point is 180-250 ℃, and the number of agglutinated particles is less than or equal to 5/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, continuously putting the filtrate into a magnetic fluid impurity remover after precipitation and impurity removal, rotationally mixing FeO magnetic fluid and the filtrate in the impurity remover, then disconnecting a magnetic base of the impurity remover to change the magnetic base into a permanent magnetic field, and after 10-20 minutes, downwards precipitating and layering magnetic particles to filter and remove nylon, spandex, a delustering agent, titanium dioxide and the like; 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, adding anhydrous ethanol, standing for 20-30 min, adjusting pH, and continuing to mixRaising the temperature, rapidly stirring 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 waste polyester depolymerization liquid is subjected to precipitation adsorption treatment and magnetic fluid sedimentation treatment, so that impurities in depolymerization products can be effectively reduced; 5) the preparation of the copolyester amide can be realized by adding a set of polyamide feeding device on the original polyester depolymerization regeneration equipment, and the industrial production is easy to carry out.

Detailed Description