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KR-20260067164-A - METHOD FOR REDUCING ODOR OF POLYOLEFIN RECYCLED RESIN

KR20260067164AKR 20260067164 AKR20260067164 AKR 20260067164AKR-20260067164-A

Abstract

The present invention relates to a method for reducing the odor of a polyolefin recycled resin, comprising the steps of preparing an extrusion feed containing a polyolefin recycled raw material and feeding the extrusion feed into an extruder to extrude and then pelletizing to obtain pellets, wherein the method comprises adding an odor reducing agent in an amount of 0.01% to 0.2% by weight relative to the total weight of the polyolefin recycled resin to one or more selected from the extrusion feed and the pellets, and wherein the odor reducing agent comprises a vegetable oil containing a terpene component.

Inventors

  • 김재영
  • 오현택
  • 김호훈

Assignees

  • 주식회사 엘지화학

Dates

Publication Date
20260512
Application Date
20241105

Claims (11)

  1. A step of preparing an extrusion feed containing recycled polyolefin raw materials, and A process for manufacturing a polyolefin recycled resin comprising the step of feeding the above extrusion feed into an extruder, extruding it, and then pelletizing it to obtain pellets, wherein The method comprises adding an odor reducing agent to one or more selected from the extruded feed and the pellets in an amount of 0.01% to 0.2% by weight based on the total weight of the recycled polyolefin resin. A method for reducing the odor of a recycled polyolefin resin, wherein the above-mentioned odor reducing agent comprises a vegetable oil containing a terpene component.
  2. In paragraph 1, A step of preparing an extruded feed by first adding the above odor reducing agent to the recycled polyolefin raw material; A step of extruding the above extrusion feed and pelletizing it to obtain pellets; and A method for reducing the odor of a recycled polyolefin resin, comprising the step of secondarily adding the odor reducing agent to the pellet.
  3. In paragraph 2, A method for reducing odors in recycled polyolefin resin, wherein the weight ratio of the first odor reducing agent and the second odor reducing agent is 7:3 to 9:1.
  4. In paragraph 1, A method for reducing the odor of recycled polyolefin resin, wherein the above-mentioned recycled polyolefin raw material is crushed and wet-washed.
  5. In paragraph 1, A method for reducing the odor of a polyolefin recycled resin, wherein the above-mentioned polyolefin recycled raw material includes polyethylene resin.
  6. In paragraph 5, A method for reducing the odor of recycled polyolefin resin, wherein the polyethylene resin is selected from low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), or a mixture thereof.
  7. In paragraph 1, A method for reducing the odor of a polyolefin recycled resin, wherein the amount of the odor reducing agent added relative to the total weight of the polyolefin recycled resin is 0.01 weight% to 0.1 weight%.
  8. In paragraph 1, A method for reducing the odor of a recycled polyolefin resin, wherein the above-mentioned odor reducing agent comprises 1% to 30% by weight of a terpene component.
  9. In paragraph 1, A method for reducing the odor of recycled polyolefin resin, wherein the internal temperature of the extruder is 180°C to 280°C.
  10. In paragraph 1, A method for reducing the odor of recycled polyolefin resin, wherein the residence time of the extruded feed in the extruder is 0.5 minutes to 10 minutes.
  11. In paragraph 1, A method for reducing the odor of recycled polyolefin resin, wherein the internal pressure of the extruder is 10 bar to 100 bar.

Description

Method for Reducing Odor of Polyolefin Recycled Resin The present invention relates to a method for removing odors while minimizing the degradation of optical properties of recycled polyolefin resins. Recently, the use of plastics has been increasing due to the development of plastics with properties required for various applications and purposes. Generally, the production of plastics, from crude oil extraction to manufacturing, consumes a significant amount of energy and emits large quantities of carbon. Furthermore, when the plastic contained within a final product is discarded along with it, it leads to environmental pollution and incurs social costs for disposal. Therefore, the recycling of discarded plastics is essential for reducing energy consumption, lowering carbon emissions, and preventing environmental pollution. Plastics produced by recycling used plastics discarded by end consumers are called post-consumer recycled (PCR) resins, and continuous attempts and efforts are being made to obtain PCR resins with desired purity and properties. Meanwhile, polyolefin (PO) resins are thermoplastic polymers produced by polymerizing olefins (hydrocarbons containing one double bond per molecule), such as ethylene and propylene. They exhibit different properties depending on their density and are used as raw materials for various products based on density. For example, high density exhibits properties such as plasticity, rigidity, and uniformity, while low density exhibits properties such as elasticity (like liquid or rubber), transparency, and flexibility. Accordingly, high-density polyethylene (HDPE) is mainly used for products requiring high strength, low-density polyethylene (LDPE) is mainly used for products requiring high transparency, and linear low-density polyethylene (LLDPE) is mainly used for film production due to its excellent moldability. These polyolefin resins are widely used commercially at low prices and account for a significant portion of currently generated waste plastics. Generally, methods for recycling waste plastics (resins) include mechanical recycling, chemical recycling, and thermal recycling. Mechanical recycling involves crushing and sorting collected waste plastics to separate them by type, then melting them using an extruder and manufacturing resin products by mixing them with virgin material in a specific ratio or reinforcing them with functional additives during pelletization. Chemical recycling is a method that uses various chemical means to extract only specific polymers from waste plastics or recover them as pure monomers for repolymerization. Thermal recycling is a method that recovers thermal energy by burning waste plastics. When processing waste polyolefin resin using the aforementioned mechanical recycling method, if foreign substances are present, oxidation of these substances occurs during the melting process using an extruder, causing an odor of unknown origin. In particular, agricultural mulching film contains high levels of various foreign substances such as soil, straw, and paper; furthermore, due to its application characteristics, it involves a fermentation process. Consequently, if these substances oxidize at high temperatures along with various compounds during the pelletization process, the resulting odor is severe. Accordingly, methods are being attempted to use additives such as zeolite-based materials or zinc ricinoleate, which are known to have the ability to remove odors or TVOC (total volatile organic compounds) during the regeneration process of waste polyolefin resins. However, most of these additives are highly polar substances and have poor miscibility with the resin. Consequently, if an excessive amount of additive is introduced, a phase may form within the matrix resin, and the introduction of such polarity-different components acts as defect sites in the matrix resin, which can result in a degradation of optical properties such as the transmittance of the resin. Therefore, there is a need for a technology that can prevent optical degradation while eliminating odors during the regeneration of waste polyolefin resins, such as agricultural mulching films. Terms and words used in the description and claims of the present invention shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. In relation to the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of the noun corresponding to the item may include one or more of the said item unless the relevant context clearly indicates otherwise. In the present disclosure, each of the phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at l