Efficient and energy-saving gauze PET dust-free film production circulation process

Abstract

The invention discloses a high-efficiency and energy-saving gauze PET dust-free film production cycle process, and relates to the technical field of PET film production.The process comprises the steps that waste in a PET film production line is pretreated, then the production waste is subjected to an alcoholysis reaction, and after the alcoholysis reaction is finished, a product is separated and purified; dMT (dimethyl terephthalate) and EG (ethylene glycol) obtained after purification are reused; in the invention, a PET dust-free film production cycle process is adopted, leftover materials, unqualified products and trimming wastes which are inevitably produced in the PET film production process and intermediate products which are incompletely reacted or do not meet the quality requirement and are produced in a raw material treatment stage are recycled and reused, and the pollution of plastic wastes to the environment is reduced; meanwhile, by recycling the waste materials, a large amount of raw material resources such as petroleum can be saved; the regenerated PET material is recycled, processed and sold, and the profit rate of an enterprise can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of PET film production, in particular to a high-efficiency and energy-saving gauze PET dust-free film production circulation process. Background Art

[0002] The production of PET film is a complex and delicate process. It starts with the polymerization reaction of terephthalic acid (PTA) and ethylene glycol (EG), and then generates ethylene terephthalate (BHET) through esterification reaction, and then forms PET polymer chains through polycondensation reaction to obtain PET particles. Subsequently, the PET particles are dried, heated and melted, and extruded into thin sheets in an extruder. After cooling, stretching and heat treatment, PET film with specific mechanical and optical properties is formed. Finally, after surface treatment and coating, slitting and winding, the PET film products that meet the requirements are obtained, which are used in various fields such as packaging, electrical insulation and decoration.

[0003] In the production process of PET film, it is inevitable to produce scraps, defective products, trimming waste and intermediate products with incomplete reactions or substandard quality produced in the raw material processing stage. If these production wastes are not recycled, they are difficult to degrade in the natural environment and will cause pollution. At the same time, these valuable resources cannot be effectively utilized, resulting in waste of resources. Therefore, an efficient and energy-saving gauze PET dust-free film production recycling process is proposed. Summary of the invention

[0004] The purpose of the present invention is to provide an efficient and energy-saving tulle PET dust-free film production recycling process to solve the problem that if the production waste is not recycled, the waste will be difficult to degrade in the natural environment and cause pollution, and at the same time these valuable resources cannot be effectively utilized, resulting in waste of resources.

[0005] To achieve the above object, the present invention provides the following technical solution: a high-efficiency and energy-saving tulle PET dust-free film production cycle process, comprising the following steps: S1. Waste pretreatment; S2, alcoholysis reaction; S3, separation and purification; S4. Reuse.

[0006] Preferably, the waste pretreatment comprises the following steps: S11. Collect and sort the waste from the PET film production line to remove non-recyclable impurities; S12, crushing the recycled renewable waste into fine particles using a crusher, and using a combination of ultrasonic cleaning and deionized water rinsing to thoroughly remove grease, dust and pollutants on the surface of the particles; S13. Dry the cleaned particles using a hot air dryer or a vacuum drying oven to ensure that the moisture content is less than 0.5%.

[0007] Preferably, the alcoholysis reaction comprises the following steps: S21. Add the dried particles, alcoholysis agent (methanol) and catalyst (zinc acetate) into a reactor, control the reaction temperature at 200-280°C, the reaction pressure at 2-6 MPa, and the reaction time at 2-3 hours.

[0008] Preferably, the separation comprises the following steps: S31, after the alcoholysis reaction is completed, the product is separated from the reaction mixture by cooling, precipitation, filtration and centrifugation; S32. The mixture of unreacted alcoholysis agent and catalyst is further separated by distillation or extraction.

[0009] Preferably, the purification comprises the following steps: S33, purifying the separated product by multi-stage distillation to improve purity and quality; S34. Detect the purified product to check its purity, melting point, molecular weight and other indicators.

[0010] Preferably, the reuse comprises the following steps: S41, reusing the purified DMT to produce polyester materials, coatings, resins and plasticizers; S42. The purified EG is reused for the production of polyester fibers, antifreeze agents and solvents.

[0011] Preferably, the reactor is equipped with an efficient stirring and heating system, and an accurate temperature and pressure control system; Reaction equation: PET + alcoholysis agent → DMT (dimethyl terephthalate) + EG (ethylene glycol).

[0012] In the present invention, a PET dust-free film production recycling process is adopted to recycle and reuse the scraps, unqualified products, trimming wastes and intermediate products with incomplete reactions or substandard quality generated in the raw material processing stage that are inevitably generated in the PET film production process, thereby reducing the pollution of plastic waste to the environment; at the same time, recycling and reusing these wastes can save a large amount of raw material resources such as petroleum; recycling, processing and selling recycled PET materials can improve the profit margin of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a high-efficiency energy-saving gauze PET dust-free film production cycle process flow chart. DETAILED DESCRIPTION

[0014] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0015] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example See also Figure 1 As shown, a high-efficiency and energy-saving tulle PET dust-free film production cycle process comprises the following steps: Step 1: waste pretreatment; Specifically, the waste pretreatment includes the following steps: collecting and sorting the waste from the PET film production line, removing non-recyclable impurities, ensuring that the waste collected from the PET film production line is pure PET material, avoiding mixing with other types of plastics or impurities, and using physical methods such as magnetic separation and air separation to remove metal and non-PET impurities; using a crusher to crush the recycled renewable waste into fine particles, using a high-efficiency crusher to crush the waste into fine particles to increase the contact area for subsequent reactions, and using a combination of ultrasonic cleaning and deionized water rinsing to thoroughly remove grease, dust and pollutants on the surface of the particles; using a hot air dryer or a vacuum drying oven to dry the cleaned particles to ensure that the moisture content is less than 0.5%, and the dried particles should be stored in a sealed, dry and cool environment to avoid moisture and oxidation.

[0018] Step 2, alcoholysis reaction; Specifically, the dried particles, alcoholysis agent (methanol) and catalyst (zinc acetate) are added into a reactor, the reaction temperature is controlled at 200-280°C, the reaction pressure is controlled at 2-6MPa, the reaction time is 2-3 hours, and the reaction equation is: PET + alcoholysis agent → DMT (dimethyl terephthalate) + EG (ethylene glycol).

[0019] Step 3: separation and purification; Specifically, the separation includes the following steps: after the alcoholysis reaction is completed, the product is separated from the reaction mixture by cooling, precipitation, filtration and centrifugation; the unreacted alcoholysis agent and catalyst mixture is further separated by distillation or extraction; Specifically, the purification includes the following steps: the separated product is purified by multi-stage distillation to improve the purity and quality. The separated product may contain certain impurities, such as unreacted alcoholysis agent, catalyst residue, etc. Therefore, the product needs to be purified to improve its purity and quality. The purification methods include recrystallization, multi-stage distillation, extraction, etc.; the purified product is tested to test the purity, melting point, molecular weight and other indicators to ensure that the product meets the requirements of subsequent reuse.

[0020] Step 4: Reuse; Specifically, the purified DMT is reused to produce polyester materials, coatings, resins and plasticizers; DMT can undergo ester exchange reactions with other diol compounds (such as 1,4-butanediol, ethylene glycol, etc.), and then undergo polycondensation reactions to generate different types of polyester materials. These polyester materials have good physical and chemical properties and can be used to manufacture fibers, films, containers, etc.; DMT can also be used as a raw material for the production of coatings and resins. Through specific chemical reactions, DMT can be converted into coatings and resins with excellent properties for coating and protection in the fields of construction, automobiles, furniture, etc.; DMT can also be used as a raw material for the production of plasticizers, which can increase the flexibility and ductility of plastics, making them more suitable for specific application scenarios; Specifically, the purified EG is reused to produce polyester fibers, antifreeze and solvents. EG is an important raw material for producing polyester fibers (such as polyester). It can be synthesized into polyester fibers through polycondensation with other dibasic acids (such as terephthalic acid). EG can also be used as a raw material for antifreeze. Antifreeze is mainly used in the fields of automobiles, mechanical equipment, etc. to prevent the cooling system from freezing and being damaged under cold conditions. EG has a certain solubility and can be used as a solvent or solvent component in the production of coatings, inks, resins and other fields.

[0021] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-efficiency and energy-saving tulle PET dust-free film production cycle process, characterized in that: The following steps are involved: S1. Waste pretreatment; S2, alcoholysis reaction; S3, separation and purification; S4. Reuse.

2. A high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claim 1, characterized in that: In step S1, the waste pretreatment comprises the following steps: S11. Collect and sort the waste from the PET film production line to remove non-recyclable impurities; S12, crushing the recycled renewable waste into fine particles using a crusher, and using a combination of ultrasonic cleaning and deionized water rinsing to thoroughly remove grease, dust and pollutants on the surface of the particles; S13. Dry the cleaned particles using a hot air dryer or a vacuum drying oven to ensure that the moisture content is less than 0.5%.

3. A high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claim 1, characterized in that: In step S2, the alcoholysis reaction comprises the following steps: S21. Add the dried particles, alcoholysis agent (methanol) and catalyst (zinc acetate) into a reactor, control the reaction temperature at 200-280°C, the reaction pressure at 2-6 MPa, and the reaction time at 2-3 hours.

4. The high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claim 1 is characterized in that: In step S3, the separation comprises the following steps: S31, after the alcoholysis reaction is completed, the product is separated from the reaction mixture by cooling, precipitation, filtration and centrifugation; S32. The mixture of unreacted alcoholysis agent and catalyst is further separated by distillation or extraction.

5. The high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claim 1 is characterized in that: In step S3, the purification comprises the following steps: S33, purifying the separated product by multi-stage distillation to improve purity and quality; S34. Detect the purified product to check its purity, melting point, molecular weight and other indicators.

6. The high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claim 1 is characterized in that: In step S4, the reuse comprises the following steps: S41, reusing the purified DMT to produce polyester materials, coatings, resins and plasticizers; S42. The purified EG is reused for the production of polyester fibers, antifreeze agents and solvents.

7. A high-efficiency and energy-saving tulle PET dust-free film production cycle process according to claims 2 to 6, characterized in that: The reactor is equipped with an efficient stirring and heating system, as well as an accurate temperature and pressure control system; Reaction equation: PET + alcoholysis agent → DMT (dimethyl terephthalate) + EG (ethylene glycol).

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