CN112759746A - Preparation method of high-cleanness food grade recycled bottle flakes - Google Patents
Preparation method of high-cleanness food grade recycled bottle flakes Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/181—Acids containing aromatic rings
- C08G63/183—Terephthalic acids
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/181—Acids containing aromatic rings
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- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/66—Polyesters containing oxygen in the form of ether groups
- C08G63/668—Polyesters containing oxygen in the form of ether groups derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/672—Dicarboxylic acids and dihydroxy compounds
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- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
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Abstract
The invention provides a preparation method of high-cleanness food grade recycled bottle tablets. The method comprises the steps of sequentially crushing, cleaning and drying colorless waste PET polyester bottles, adding the dried materials into a three-section single-shaft screw extruder with an air extractor by virtue of a feeding system, and carrying out three-section depolymerization and filtration to obtain colorless waste PET polyester bottle non-sticky or low-viscosity depolymerization products; mixing colorless waste PET polyester bottle filter melt with PET production raw materials, carrying out polycondensation reaction on the mixed melt in a reaction kettle, and carrying out casting and granulating after the reaction is finished to obtain particles with the intrinsic viscosity of 0.60-0.64 dL/g; drying and pre-crystallizing the particles, and then feeding the particles into a solid phase tackifying reactor, wherein the reaction temperature is 200-230 ℃, the reaction time is 14-20h, and after solid phase tackifying, obtaining the target product bottle grade slices. The non-produced product can be used for food-grade bottle flakes, such as water bottles, carbonic acid bottles, oil bottles and other fields, meets the requirements of environmental protection and circular economy, meets the food-grade use requirements, and keeps the economic competitive advantage.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a preparation method of high-cleanness food grade recycled bottle flakes.
Background
Polyethylene Terephthalate (PET, polyester for short) is a widely used synthetic polymer material. When being used as a bottle, PET has the advantages of no smell, no toxicity, light weight, good air tightness, high transparency and the like, and is widely applied to the fields of food-grade packaging, cosmetics, medicines, health care and the like. With the large number of applications of PET bottles, white contamination and secondary utilization problems caused thereby are also becoming more serious. How to more effectively realize the high-level recycling of the waste PET bottles becomes a research hotspot at home and abroad. The recovery technology of the PET polyester bottle at present is divided into physical recovery technology and chemical recovery technology. The physical recovery is to heat and melt the waste polyester, and then extrude and granulate the waste polyester through a screw extruder after purification, and the general process is as follows: classifying, crushing, cleaning, dehydrating, drying and granulating. The chemical recovery method is to depolymerize the waste polyester into low molecular compounds such as terephthalic acid (PTA), dimethyl terephthalate (DMT), ethylene terephthalate (BHET) and the like through chemical reaction, and alcoholysis products can be used as raw materials to participate in polymerization reaction after being purified. The chemical recovery method also comprises chemical modification, and chain length and structure of the polyester are changed by adopting chain extension modification, crosslinking modification, chlorination modification and the like, so that certain properties are improved. The chemical recovery method can really realize the application from bottle to bottle, but the route from depolymerization and purification to monomer has the problems of high energy consumption, poor economic benefit and the like.
At present, a physical recovery method is the leading of a polyester re-production industrialized technology, but the quality of a product regenerated by a traditional physical method is obviously reduced compared with the original product, the intrinsic viscosity reduction and fluctuation are greatly influenced by process conditions, meanwhile, filtration and volatile impurity removal of infusible impurities are difficult due to the large melt viscosity in the process, and the excessive impurities are not removed in time in the high-temperature processing process, so that various irreversible cracking degradation is caused to cause the increase of the acetaldehyde content. Polyester particles prepared by recovering waste polyester bottles through a physical method need to be subjected to solid-phase tackifying to improve the intrinsic viscosity, and then are mixed with fresh polyester chips for use according to a certain proportion, and particularly, the waste materials and the fresh materials are forbidden to be mixed by Chinese laws and regulations to prepare the food-grade bottle chips. In the chemical method, the polyester is depolymerized into monomers, so that the waste polyester can be effectively recycled, the quality of a regenerated product is as good as that of a primary product, but the chemical method has long process flow, low efficiency and high cost, and only a few enterprises in the United states and Japan carry out small-scale industrialization attempts at present.
Chinese patent ZL 200610157145.8 provides a production process for manufacturing food-grade polyester bottle chips by utilizing polyester recovery bottles, aiming at the characteristics of the recovery PET bottles, the invention firstly cleans, crushes the recovery polyester bottles into chips, separates impurities, and effectively removes bottle bodies, volume labels, impurities, foreign matters and the like; then, aiming at the residual substances of the recovered PET bottle, a corresponding trace impurity removal process is added, and trace PVC, PP, PE and other mechanical impurities are further removed; finally, solid-phase polycondensation is carried out to produce the food-grade PET slice. This patent will retrieve the broken material of PET bottle and extrude the granulation through screw extruder, utilizes the volatile material of vacuum desorption in extrusion process, and the volatile material of unable degree of depth desorption and melt viscosity, quality can't obtain stable control.
Chinese patent ZL 201120502846.7 discloses a system for recycling waste polyester bottles, including the polymerization system of recycling, the clean system that the accessory substance was collected and solvent cyclic utilization, and the polymerization system includes waste polyester bottle melting alcoholysis system, polycondensation system and masterbatch injection system, and waste polyester bottle melting alcoholysis system includes screw rod melting unit and alcoholysis cauldron, and the polycondensation system includes pre-polycondensation unit and final polycondensation unit. In the above patent, PET is made by partial alcoholysis followed by deep alcoholysis and then repolymerization. Although the method can carry out deep alcoholysis on the PET to form a mixed solution of BHET/EG, and harmful impurities are removed, the PET alcoholysis reaction is an endothermic reaction, and the adoption of deep and complete alcoholysis can cause huge energy consumption waste, improve the production cost and reduce the economic benefit of products. Meanwhile, PET can form cyclic polymers and oligomers during deep alcoholysis, cannot be sufficiently separated from BHET, and the cyclic polymers and the oligomers can improve the crystallization rate of PET when entering a reaction system, so that the regenerated bottle flakes are easy to fog in the post-addition process.
Disclosure of Invention
The invention provides a physical-chemical method combined process aiming at the problems of poor physical method performance and high alcoholysis energy consumption of a chemical method of the existing colorless waste polyester bottle recovery process, and the recovery process has the advantages of low recovery energy consumption, online adjustable recycling bottle amount and high product quality.
The purpose of the invention can be realized by the following technical scheme:
a preparation method of high-cleanness food grade recycled bottle flakes comprises the steps of sequentially crushing, cleaning and drying colorless waste PET (polyethylene terephthalate) bottles, feeding the dried materials into a three-section screw extruder system, so that colorless waste PET materials are subjected to first-section melt plasticization, second-section vacuum devolatilization and third-section depolymerization in a screw, and are subjected to third-section depolymerization and filtration to obtain a low-viscosity depolymerization product of the colorless waste PET bottles; mixing the colorless waste PET polyester bottle low-viscosity polymer with PET production raw materials, carrying out polycondensation reaction on the mixed melt in a reaction kettle, and carrying out casting and granulating after the reaction is finished to obtain particles with the intrinsic viscosity of 0.60-0.64 dL/g; drying and pre-crystallizing the particles, and then feeding the particles into a solid phase tackifying reactor, wherein the reaction temperature is 200-230 ℃, the reaction time is 14-20h, and after solid phase tackifying, obtaining the target product bottle grade slices.
The technical scheme of the invention is as follows: the temperature for the first stage of melt plastification is 275-295 ℃.
The technical scheme of the invention is as follows: the operation of the second stage vacuum devolatilization is that the absolute pressure is 50-4000Pa, and the operation temperature is 280-295 ℃.
The technical scheme of the invention is as follows: the third-stage depolymerization temperature is 260-275 ℃, and the addition amount of the depolymerization product accounts for 0.2-1.0 wt% of the weight of the colorless waste PET polyester bottle; after the depolymerization reaction is finished, the temperature of the screw is reduced to 260 ℃ of 230-; preferably: the low-viscosity polymer of the colorless waste PET polyester bottle contains phosphoric acid accounting for 0.5-30ppm of the weight of the extruded melt; further preferably: the low-viscosity polymer of the colorless waste PET polyester bottle contains phosphoric acid accounting for 0.5-20ppm of the weight of the extruded melt; most preferably: the low-viscosity depolymerization product of colorless waste PET polyester bottles contains phosphoric acid in an amount of 1 to 20ppm based on the weight of the extruded melt.
The technical scheme of the invention is as follows: the depolymerization product is one or more of water, ethylene glycol, diethylene glycol, methanol and ethanol; preferably: the depolymerization products are ethylene glycol and diethylene glycol.
The technical scheme of the invention is as follows: the PET production raw materials are terephthalic acid, isophthalic acid, ethylene glycol, phosphoric acid, sodium acetate and ethylene glycol antimony, wherein: 30.5-69.2 parts of terephthalic acid, 14.5-29 parts of ethylene glycol and 1.6-5.0 parts of isophthalic acid in sequence; the phosphoric acid accounts for 10-50 ppm of the total weight of the synthetic polyester, the sodium acetate accounts for 30-80 ppm of the total weight of the synthetic polyester, and the ethylene glycol antimony accounts for 150-200 ppm of the total weight of the synthetic polyester.
The technical scheme of the invention is as follows: the colorless waste PET polyester bottle accounts for 0-50 wt% of the target product; preferably: the colorless waste PET polyester bottle accounts for 5-50 wt% of the target product; further preferably: the colorless waste PET polyester bottle accounts for 10-20 wt% of the target product.
The technical scheme of the invention is as follows: the colorless waste polyester bottle cleaning crumble was depolymerized in a third stage single-screw extruder to an intrinsic viscosity of 0.1-0.4 dL/g.
The technical scheme of the invention is as follows: the third stage screw extruder system employed was the MRS single shaft planetary screw system of grantis, germany. The screw is designed in a single main shaft three-section mode, the front section and the rear section are single screws, and the middle section is a single screw with a planetary screw kneading function.
The invention has the beneficial effects that:
the invention provides a preparation method of high-cleanness food grade recycled bottle tablets. The colorless waste PET bottle can be flexibly adjusted according to the adding amount, and the contents of IPA, phosphoric acid, ether inhibitor and the like in the fresh melt are adjusted according to the adding amount of the waste polyester bottle. The colorless waste bottles are depolymerized by a screw, conveyed by a low-temperature pipeline, depolymerized by reaction and devolatilized in vacuum, so that the problems of color difference, high content of acetaldehyde and harmful impurities, unadjustable quantity of recycled waste bottles, high energy consumption and wide molecular weight distribution are solved, the produced product can be used in food-grade bottle flakes, such as water bottles, carbonic acid bottles, oil bottles and other fields, the requirements of environmental protection and circular economy are met, the food-grade use requirements are met, and the economic competitive advantage is kept.
Drawings
FIG. 1 is a process flow diagram of the production method of the present invention.
Detailed Description
The invention is further illustrated by the following examples, without limiting the scope of the invention:
the common bottle grade polyester chip contains 1.8 percent of isophthalic acid based on the total weight, and the content of the isophthalic acid in the colorless waste polyester bottle is also 1.8 percent, so the addition proportion of the isophthalic acid in the virgin fresh PET melt in the invention is reset after the isophthalic acid in the colorless waste polyester bottle is deducted.
The technical scheme of the invention is as follows: the three-stage screw extruder system used was the MRS single-shaft planetary screw system of Glosso, Germany with an air extractor. The screw is designed in a single main shaft three-section mode, the front section and the rear section are single screws, and the middle section is a single screw with a planetary screw kneading function.
Example 1:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 62.3 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 1.6 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 26.1 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 10 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: after the colorless waste PET polyester bottle is crushed, washed by water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by a feeding system, the three-section type single-shaft screw extruder adopts a first section of melting plasticization at 285 ℃, a second section of devolatilization at 280 ℃ and 50Pa absolute vacuum, a third section of hydrolysis (the adding amount of water accounts for 0.5 wt% of the weight of the colorless waste polyester bottle, phosphoric acid in water accounts for 5ppm of the weight of a depolymerized melt and the reaction temperature is 260 ℃), the colorless waste polyester bottle cleaning crushed material is depolymerized to a low-viscosity melt of 0.12dL/g in the third section type single-shaft screw extruder, the pipeline conveying temperature and the screw temperature after depolymerization are reduced to 250 ℃, and the low-viscosity melt is subjected to a 20-mesh high-precision melt filter to obtain the colorless.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting a belt and granulating, wherein the inherent viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.98; drying and pre-crystallizing the particles, then feeding the particles into a solid phase tackifying reactor, and reacting for 18 hours at the reaction temperature of 210 ℃ to prepare bottle-grade slices, wherein the intrinsic viscosity is 0.82dL/g, the molecular weight distribution is 2.11, the acetaldehyde content is 0.9ppm, the hue L: 80. a: -1.56, b: -2.9, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 247 ℃, the melting crystallization temperature is 169 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm.
Example 2:
the PET bottle grade resin is prepared by taking terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles, phosphoric acid, sodium acetate and ethylene glycol antimony as raw materials, wherein the consumption of each raw material and the treatment of the colorless waste PET polyester bottles are the same as those in example 1, except that the melting depolymerization product is adjusted to be the ethylene glycol, the ethylene glycol is depolymerized to be low-viscosity melt of 0.28dL/g, the other process conditions are the same as those in example 1, the PET bottle grade resin is cast and granulated after polycondensation, the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.95. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor, and react for 18 hours at the reaction temperature of 210 ℃ to prepare bottle-grade slices, wherein the intrinsic viscosity is 0.82dL/g, the molecular weight distribution is 2.05, the acetaldehyde content is 0.7ppm, the hue L: 83. a: -1.57, b: -2.92, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 247 ℃, the melting crystallization temperature is 167 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm. .
Example 3:
the PET bottle grade resin is prepared by taking terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles, phosphoric acid, sodium acetate and ethylene glycol antimony as raw materials, wherein the dosage of each raw material and the treatment of the colorless waste PET polyester bottles are the same as those in example 1, except that the melting depolymerization product is adjusted to be diethylene glycol, the ethylene glycol is depolymerized to be low-viscosity melt of 0.34dL/g, the other process conditions are the same as those in example 1, the PET bottle grade resin is cast and granulated after polycondensation, the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 2.01. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor, and react for 18 hours at the reaction temperature of 210 ℃ to prepare bottle-grade slices, wherein the intrinsic viscosity is 0.82dL/g, the molecular weight distribution is 2.11, the acetaldehyde content is 0.92ppm, the hue L: 81. a: -1.62, b: -2.89, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 248 ℃, the melting crystallization temperature is 164 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm.
Example 4:
the PET bottle grade resin is prepared by taking terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles, phosphoric acid, sodium acetate and ethylene glycol antimony as raw materials, wherein the consumption of each raw material and the treatment of the colorless waste PET polyester bottles are the same as those in example 1, except that the melting depolymerization product is adjusted to be methanol, the methanol is depolymerized to be low-viscosity melt of 0.16dL/g, the other process conditions are the same as those in example 1, the PET bottle grade resin is cast and granulated after polycondensation, the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.97. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor, and react for 20 hours at the reaction temperature of 210 ℃ to prepare bottle-grade slices, wherein the intrinsic viscosity is 0.82dL/g, the molecular weight distribution is 2.06, the acetaldehyde content is 0.8ppm, the hue L: 82. a: -1.58, b: -2.89, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 249 ℃, the melting crystallization temperature is 170 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm.
Example 5:
the PET bottle grade resin is prepared by taking terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles, phosphoric acid, sodium acetate and ethylene glycol antimony as raw materials, wherein the consumption of each raw material and the treatment of the colorless waste PET polyester bottles are the same as those in example 1, except that the melting depolymerization product is adjusted to be ethanol and is depolymerized to be low-viscosity melt of 0.21dL/g, the other process conditions are the same as those in example 1, the PET bottle grade resin is cast and granulated after polycondensation, the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.96. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor, and react for 19 hours at the reaction temperature of 210 ℃ to prepare bottle-grade slices, wherein the intrinsic viscosity is 0.82dL/g, the molecular weight distribution is 2.07, the acetaldehyde content is 0.9ppm, the hue L: 83. a: -1.54, b: -2.87, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 250 ℃, the melting crystallization temperature is 169 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm.
Example 6:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 62.3 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 1.8 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 26.1 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 10 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: after the colorless waste PET polyester bottle is crushed, washed by water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by virtue of a feeding system, the three-section type single-shaft screw extruder adopts the steps of melting plasticization at 285 ℃ in the first section, devolatilization at 285 ℃ under the absolute pressure of 50Pa in the second section, depolymerization of EG in three sections (the addition amount of EG accounts for 0.2 wt% of the weight of the colorless waste polyester bottle, phosphoric acid in EG accounts for 5ppm of the weight of a depolymerized melt and the reaction temperature is 260 ℃), the colorless waste polyester bottle cleaning crushed material is depolymerized to a low-viscosity melt of 0.4dL/g in the third-section type single-shaft screw extruder, the tail end temperature of the depolymerized screw and the pipeline conveying temperature are reduced to 255 ℃, and the low-viscosity melt is subjected to.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting a belt and granulating, wherein the intrinsic viscosity of particles is controlled to be 0.60dL/g, and the molecular weight distribution index is 1.94; drying and pre-crystallizing the particles, then feeding the particles into a solid phase tackifying reactor, and reacting for 20 hours at the reaction temperature of 200 ℃ to prepare a bottle grade slice, wherein the intrinsic viscosity is 0.81dL/g, the molecular weight distribution is 2.05, the acetaldehyde content is 0.7ppm, the hue L: 84. a: -1.46, b: -3.2, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 248 ℃, the melting crystallization temperature is 165 ℃, and the olefin impurities such as PVC, PP and the like are less than 6 ppm.
Example 7:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 54.8 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 2.0 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 23.2 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 20 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: the colorless waste PET polyester bottle is crushed, washed with water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by virtue of a feeding system, the three-section type single-shaft screw extruder is melted and plasticized at 285 ℃ in the first section, devolatilized at 290 ℃ under the absolute pressure of 500Pa in the second section, and depolymerized to 0.35dL/g of low-viscosity melt by cleaning and crushing the colorless waste polyester bottle in the three-section type single-shaft screw extruder (the addition amount of EG accounts for 0.3 wt% of the weight of the colorless waste polyester bottle, the phosphoric acid in EG accounts for 0.5ppm of the weight of the depolymerized melt, and the reaction temperature is 255 ℃), and the tail end temperature of the screws and the pipeline conveying temperature after depolymerization are reduced to 250 ℃, and the low-viscosity melt is subjected to a high-precision melt filter 20 meshes.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting, granulating, wherein the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.95. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor to react for 18 hours at the reaction temperature of 210 ℃, and the prepared bottle-grade slices have the intrinsic viscosity of 0.82dL/g, the molecular weight distribution of 2.08, the acetaldehyde content of 0.8ppm, the hue L: 83. a: -1.57, b: -3.02, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 247 ℃, the melting crystallization temperature is 164 ℃, and the olefin impurities such as PVC, PP and the like are less than 8 ppm.
Example 8:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 46.7 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 3.0 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 20.3 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 30 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: the colorless waste PET polyester bottle is crushed, washed with water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by virtue of a feeding system, the three-section type single-shaft screw extruder is melted and plasticized at 285 ℃ in the first section, devolatilized at 290 ℃ and 1000Pa in the second section, and depolymerized to 0.28dL/g of low-viscosity melt by using EG (the addition amount of EG accounts for 0.5 wt% of the weight of the colorless waste polyester bottle, phosphoric acid accounts for 10ppm of the weight of the depolymerized melt in EG, and the reaction temperature is 250 ℃) in the three-section type single-shaft screw extruder, and the colorless waste polyester bottle cleaning crushed material is depolymerized to 240 ℃ in the three-section type single-shaft screw extruder, and the tail end temperature of the depolymerized screw and the pipeline conveying temperature are reduced to 240.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting, granulating, wherein the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.96. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor to react for 18 hours at the reaction temperature of 210 ℃, and the prepared bottle-grade slices have the intrinsic viscosity of 0.82dL/g, the molecular weight distribution of 2.09, the acetaldehyde content of 0.6ppm, the hue L: 82. a: -1.51, b: -3.1, the crystallization performance is similar to that of the conventional bottle grade slices, the melting point is 246 ℃, the melting crystallization temperature is 175 ℃, and the olefin impurities such as PVC, PP and the like are less than 8 ppm.
Example 9:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 38.6 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 4.0 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 17.4 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 40 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: the colorless waste PET polyester bottle is crushed, washed with water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by virtue of a feeding system, the three-section type single-shaft screw extruder is melted and plasticized at 285 ℃, devolatilized at 295 ℃ and 2000Pa in vacuum, and depolymerized to low-viscosity melt of 0.16dL/g in the three-section type single-shaft screw extruder, wherein the addition amount of EG accounts for 0.8 wt% of the weight of the colorless waste polyester bottle, phosphoric acid accounts for 20ppm of the weight of the depolymerized melt in EG, and the reaction temperature is 240 ℃, and the low-viscosity melt is obtained after passing through a high-precision melt filter of 20 meshes.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting, granulating, wherein the intrinsic viscosity of particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.96. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor to react for 18h at the reaction temperature of 210 ℃, and the prepared bottle-grade slices have the intrinsic viscosity of 0.82dL/g, the molecular weight distribution of 2.09, the acetaldehyde content of 0.7ppm, the hue L: 81. a: -1.5, b: -3.2, the crystallization performance is similar to that of the conventional bottle grade slice, the melting point is 244 ℃, the melting crystallization temperature is 170 ℃, and the olefin impurities such as PVC, PP and the like are lower than 9 ppm.
Example 10:
the PET bottle-grade resin is prepared from terephthalic acid, isophthalic acid, ethylene glycol, colorless waste PET polyester bottles and phosphoric acid as raw materials, wherein the terephthalic acid accounts for 30.5 percent of the total weight of the synthetic polyester, the isophthalic acid accounts for 5.0 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 14.5 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottles account for 50 percent of the total weight of the synthetic polyester, the phosphoric acid accounts for 20ppm of the total weight, the sodium acetate accounts for 50ppm of the total weight, and the ethylene glycol antimony accounts for 170ppm of the total weight.
Preparing a colorless waste PET polyester bottle filter melt: the colorless waste PET polyester bottle is crushed, washed with water/alkali and dried (the water content is lower than 200ppm), the colorless waste PET polyester bottle is added into a three-section type single-shaft screw extruder with an air extractor by virtue of a feeding system, the three-section type single-shaft screw extruder is melted and plasticized at 285 ℃, devolatilized at 295 ℃ under vacuum and under the absolute pressure of 4000Pa, and depolymerized to a low-viscosity melt of 0.10dL/g in the three-section type single-shaft screw extruder, wherein the addition amount of EG accounts for 1.0 wt% of the weight of the colorless waste polyester bottle, phosphoric acid in EG accounts for 30ppm of the weight of the depolymerized melt, and the reaction temperature is 240 ℃, and the colorless waste polyester bottle cleaning crushed material is depolymerized to a low-viscosity melt of 0.10dL/g in the three-section type single-shaft screw extruder, and the tail end temperature of a screw after depolymerization and the pipeline conveying.
Preparing a primary fresh PET melt in a bottle chip production device: the terephthalic acid, the isophthalic acid and the ethylene glycol are pulped and mixed, phosphoric acid and sodium acetate (preventing glycolysis in the conventional esterification process) are added in the pulping and mixing stage, and esterification and pre-polycondensation reaction are carried out after pulping.
Mixing the colorless waste PET bottle filter melt and the primary fresh PET bottle melt, carrying out polycondensation reaction, and then casting, granulating, wherein the intrinsic viscosity of particles is controlled to be 0.63dL/g, and the molecular weight distribution index is 1.98. After drying and pre-crystallization, the particles enter a solid phase tackifying reactor to react for 16 hours at the reaction temperature of 220 ℃, and the prepared bottle-grade slices have the intrinsic viscosity of 0.83dL/g, the molecular weight distribution of 2.10, the acetaldehyde content of 0.9ppm, the hue L: 80. a: -1.54, b: -3.2, the crystallization performance is similar to that of the conventional bottle grade slices, the melting point is 242 ℃, the melting crystallization temperature is 174 ℃, and the olefin impurities such as PVC, PP and the like are less than 10 ppm.
Comparative example 1:
the PET bottle grade polyester is prepared from terephthalic acid, isophthalic acid, ethylene glycol and phosphoric acid as raw materials, wherein the isophthalic acid accounts for 1.8 percent of the total weight of the synthetic polyester, the terephthalic acid accounts for 69.2 percent of the total weight of the synthetic polyester, the ethylene glycol accounts for 29 percent of the total weight of the synthetic polyester, the colorless waste PET polyester bottle accounts for 0 percent of the total weight of the polyester, and the phosphoric acid accounts for (10-50) ppm of the total weight of the polyester. After the reaction of terephthalic acid, isophthalic acid, ethylene glycol and phosphoric acid in the conventional five-kettle PET process is finished, the mixture is cast into a belt and cut into particles, the intrinsic viscosity of the particles is controlled to be 0.62dL/g, and the molecular weight distribution index is 1.95. The particles enter a solid phase tackifying reactor after being dried and pre-crystallized, the reaction temperature is 220 ℃, and the reaction time is 14 hours.
The bottle grade chip prepared by the method has the intrinsic viscosity of 0.87dL/g, the molecular weight distribution of 2.05, the acetaldehyde content of less than 0.6ppm, the hue L: 85. a: -1.44, b: -2.9, the crystallization performance is similar to that of the conventional bottle grade slices, the melting point is 249 ℃, the melting crystallization temperature is 164 ℃, and all performance indexes reach the standard of the food grade bottle grade slices.
Comparative example 2:
the preparation method is characterized by comprising the following steps of melting and extruding PET bottle fragments according to the existing PET physical recovery method, controlling the extrusion temperature to be 275-290 ℃, controlling the extrusion viscosity to be within 0.05dL/g, drying and pre-crystallizing the extruded particles, and then feeding the dried and pre-crystallized extruded particles into a solid phase tackifying reactor, wherein the reaction temperature is 220 ℃, and the reaction time is 18 hours.
The intrinsic viscosity of the bottle grade chip prepared by the method is 0.84dL/g, the molecular weight distribution is 2.40, the acetaldehyde content is lower than 5ppm, and the hue L: 75. a: -1.56, b: 2.87, the crystallization performance is faster than that of the conventional bottle grade slice, the melting point is 248 ℃, the melting crystallization temperature is 185 ℃, and the olefin impurities such as PVC, PP and the like are less than 100 ppm.
TABLE 1 Effect of different depolymerization at the same colorless used bottle add-on bottle chip Performance
As shown in Table 1, under the conditions of the same amount of recycled colorless waste PET bottles, the recycling position and the addition amount of depolymerization products, the difference of the performance influence of the change of the types of the depolymerization products on the alcoholysis melt is large, although a water, methanol and ethanol system can quickly alcoholyze the colorless waste PET to a low viscosity, the thermal performance of the PET after the repolymerization is poor, the melt crystallization temperature is high, and bottle blanks are easy to fog in the subsequent bottle blowing process. The depolymerization rate of ethylene glycol and diethylene glycol is slower than that of other alcoholysis products, but the influence on the thermal performance is small, and the quality of the product can be ensured. Especially, ethylene glycol is used as one of raw materials for PET synthesis, and unreacted ethylene glycol can be pumped out by a vacuum system for final polycondensation after the ethylene glycol is added in the depolymerization process, so that the ethylene glycol can be recycled.
TABLE 2 Effect of different colorless used bottle addition ratios on bottle flake Performance under the same depolymerization
As shown in Table 2, under the condition that the alcoholysates are all ethylene glycol, with the increase of the addition of colorless waste PET, the L value of the regenerated food-grade bottle flakes is reduced, the crystallization rate is slightly increased, the content of olefin impurities is increased, but the variation range of each property is smaller than that of a pure physical law, and the bottle flakes meet the requirements in the national standard of bottle flakes. However, in terms of practicality, device operability, and the like, the difference between each index of the bottle flakes when the addition amount of the colorless waste PET is within 30% and the original PET bottle flakes is not so large, and the user acceptance degree is high.
Claims (10)
1. A preparation method of high-cleanness food grade recycled bottle flakes is characterized by comprising the following steps: the method comprises the steps of sequentially crushing, cleaning and drying colorless waste PET polyester bottles, feeding the dried material into a three-stage screw extruder system, so that the colorless waste PET material is subjected to first-stage melt plasticization, second-stage vacuum devolatilization and third-stage depolymerization in a screw, and the colorless waste PET polyester bottle low-viscosity depolymerization product is obtained after third-stage depolymerization and filtration; mixing the colorless waste PET polyester bottle low-viscosity polymer with PET production raw materials, carrying out polycondensation reaction on the mixed melt in a reaction kettle, and carrying out casting and granulating after the reaction is finished to obtain particles with the intrinsic viscosity of 0.60-0.64 dL/g; drying and pre-crystallizing the particles, and then feeding the particles into a solid phase tackifying reactor, wherein the reaction temperature is 200-230 ℃, the reaction time is 14-20h, and after solid phase tackifying, obtaining the target product bottle grade slices.
2. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the temperature for the first stage of melt plastification is 275-295 ℃.
3. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the operation of the second stage vacuum devolatilization is that the absolute pressure is 50-4000Pa, and the operation temperature is 280-295 ℃.
4. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the third-stage depolymerization temperature is 260-275 ℃, and the addition amount of the depolymerization product accounts for 0.2-1.0 wt% of the weight of the colorless waste PET polyester bottle; after the depolymerization reaction is finished, the temperature of the screw is reduced to 260 ℃ of 230-;
preferably: the low-viscosity polymer of the colorless waste PET polyester bottle contains phosphoric acid accounting for 0.5-30ppm of the weight of the extruded melt; further preferably: the low-viscosity polymer of the colorless waste PET polyester bottle contains phosphoric acid accounting for 0.5-20ppm of the weight of the extruded melt; most preferably: the low-viscosity depolymerization product of colorless waste PET polyester bottles contains phosphoric acid in an amount of 1 to 20ppm based on the weight of the extruded melt.
5. The method of preparing high-cleanliness food-grade recycled bottle flakes according to claim 4, wherein: the depolymerization product is one or more of water, ethylene glycol, diethylene glycol, methanol and ethanol.
6. The method of preparing high-cleanliness food-grade recycled bottle flakes according to claim 5, wherein: the depolymerization products are ethylene glycol and diethylene glycol.
7. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the PET production raw materials are terephthalic acid, isophthalic acid, ethylene glycol, phosphoric acid, sodium acetate and ethylene glycol antimony, wherein: 30.5-69.2 parts of terephthalic acid, 14.5-29 parts of ethylene glycol and 1.6-5.0 parts of isophthalic acid in sequence; the phosphoric acid accounts for 10-50 ppm of the total weight of the synthetic polyester, the sodium acetate accounts for 30-80 ppm of the total weight of the synthetic polyester, and the ethylene glycol antimony accounts for 150-200 ppm of the total weight of the synthetic polyester.
8. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the colorless waste PET polyester bottle accounts for 0-50 wt% of the target product.
9. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 8, wherein: the colorless waste PET polyester bottle accounts for 5-50 wt% of the target product; preferably: the colorless waste PET polyester bottle accounts for 10-20 wt% of the target product.
10. The method of making high-cleanliness food-grade recycled bottle flakes according to claim 1, wherein: the colorless waste polyester bottle cleaning crumble was depolymerized in a third stage single-screw extruder to an intrinsic viscosity of 0.1-0.4 dL/g.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114367512A (en) * | 2021-12-06 | 2022-04-19 | 界首市双特新材料科技有限公司 | Polyethylene terephthalate bottle recovery processing technology |
| CN114395226A (en) * | 2022-02-08 | 2022-04-26 | 富海(山东)包装材料有限公司 | Polyester melt czochralski sheet material process technology for recycling regenerated polyester through chemical degradation |
| CN115283423A (en) * | 2022-08-01 | 2022-11-04 | 江西龙一再生资源有限公司 | Waste polyester depolymerization treatment system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030134915A1 (en) * | 2001-12-17 | 2003-07-17 | Scantlebury Geoffrey Raymond | Production of transparent polyester using waste |
| CN107266664A (en) * | 2017-07-12 | 2017-10-20 | 宜兴市创新精细化工有限公司 | A kind of Reclaim of PET Scrap technique |
| CN108641120A (en) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | A kind of method and its recovery system of the recycling of waste and old polyester textile |
-
2019
- 2019-10-21 CN CN201910998089.8A patent/CN112759746B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030134915A1 (en) * | 2001-12-17 | 2003-07-17 | Scantlebury Geoffrey Raymond | Production of transparent polyester using waste |
| CN107266664A (en) * | 2017-07-12 | 2017-10-20 | 宜兴市创新精细化工有限公司 | A kind of Reclaim of PET Scrap technique |
| CN108641120A (en) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | A kind of method and its recovery system of the recycling of waste and old polyester textile |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114367512A (en) * | 2021-12-06 | 2022-04-19 | 界首市双特新材料科技有限公司 | Polyethylene terephthalate bottle recovery processing technology |
| CN114395226A (en) * | 2022-02-08 | 2022-04-26 | 富海(山东)包装材料有限公司 | Polyester melt czochralski sheet material process technology for recycling regenerated polyester through chemical degradation |
| CN115283423A (en) * | 2022-08-01 | 2022-11-04 | 江西龙一再生资源有限公司 | Waste polyester depolymerization treatment system |
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