How to Produce High-Quality PET Flakes for Bottle-to-Bottle Recycling

от | Июл 17, 2026 | знания, Линия переработки отходов

High-quality PET flakes are produced through a series of mechanical and washing processes that remove labels, caps, metals, PVC, adhesives, organic contaminants, and moisture from post-consumer PET bottles. A complete PET bottle washing line typically includes bale breaking, sorting, delabeling, crushing, float-sink separation, hot washing, friction washing, rinsing, dewatering, and drying. For bottle-to-bottle recycling applications, PET flakes generally require PVC content below 50 ppm, moisture below 1%, and label contamination below 100 ppm. Proper equipment configuration and process control are essential for achieving food-grade or high-purity recycled PET.

 

 

What Are High-Quality PET Flakes?

High-quality PET flakes are clean, dry, and contamination-controlled recycled PET materials suitable for reprocessing into new products.

PET flakes are produced by processing used PET bottles through shredding and washing systems. Their quality directly affects extrusion performance, IV stability, pellet quality, and end-product applications.

Typical applications include:

  • Bottle-to-bottle recycling
  • Polyester fiber production
  • PET sheet manufacturing
  • Food-grade rPET production
  • Strapping and packaging materials

 

Typical Quality Standards for PET Flakes

Параметр High-Quality Standard
PVC Content < 50 ppm
Содержание влаги < 1%
Label Content < 100 ppm
Metal Content < 20 ppm
PE/PP Contamination < 200 ppm
Bulk Density 0.25–0.40 g/cm³
Flake Size 12–16 mm

How Does a PET Bottle Washing Line Work?

Each processing stage removes a specific type of contamination to improve PET flake purity.

    Step 1: Bale Breaking

    Compressed PET bottle bales are loosened to ensure consistent material feeding.

    Equipment:

    • Bale Breaker
    • Feeding Conveyor

    Purpose:

    • Separate compacted bottles
    • Improve sorting efficiency

      Step 2: Pre-Sorting

      Foreign materials are removed before size reduction.

      Common contaminants:

      • PVC bottles
      • Металлы
      • Стекло
      • Бумага
      • Non-PET plastics

      Equipment:

      • Sorting Platform
      • Optical Sorting System
      • Metal Detector

        Step 3: Delabeling

        Labels are one of the largest contamination sources in PET recycling.

        A high-efficiency delabeler can achieve:

        • 90–98% label removal rate

        Benefits:

        • Lower glue contamination
        • Reduced washing load
        • Higher flake purity

          Step 4: Crushing

          PET bottles are reduced into uniform flakes.

          Типичный размер выходных данных:

          • 12–16 mm

          Equipment:

          • Wet Crusher
          • PET Crusher

          Benefits:

          • Increased surface area
          • Improved washing performance

            Step 5: Float-Sink Separation

            Density separation removes polyolefin contamination.

            Material behavior in water:

            Материал Плотность Результат
            PP 0,90 г/см³ Плавающий
            физкультура 0,92–0,96 г/см³ Плавающий
            ПЭТ 1,34–1,39 г/см³ Раковина
            ПВХ 1,30–1,50 г/см³ Раковина

            The system separates: PET flakes, Bottle caps, Rings, Residual labels

              Step 6: Hot Washing

              Hot washing removes adhesives, oils, and organic contaminants.

              Typical operating parameters:

              Параметр Диапазон
              Температура воды 80–95 °C
              Время удержания 15–30 минут
              Caustic Soda 1–2%

              Benefits:

              • Remove glue residue
              • Eliminate oil contamination
              • Improve flake cleanliness

                Step 7: Friction Washing

                High-speed mechanical friction removes:

                • Fine dirt
                • Label residue
                • Органические загрязнители

                Typical rotor speed:

                • 800–1200 rpm

                  Step 8: Rinsing and Neutralization

                  Clean water removes residual chemicals from the washing process.

                  Objectives:

                  • Reduce alkalinity
                  • Improve flake quality
                  • Meet downstream processing requirements

                    Step 9: Dewatering and Drying

                    Final moisture reduction is critical.

                    Equipment:

                    • Центробежная обезвоживающая машина
                    • Thermal Drying System

                    Target moisture:

                    • Ниже 1%
                    • Food-grade systems often achieve below 0.5%

                      Key Factors Affecting PET Flake Quality

                      Contamination control is more important than washing intensity alone.

                      Major Quality Risks

                      Contaminant Влияние
                      ПВХ PET degradation
                      Металлы Equipment damage
                      Метки Черные крапинки
                      Клеи Образование геля
                      Влажность Hydrolysis
                      Organics Проблемы с запахом

                       

                       

                      Common Problems and Solutions

                      Problem 1: Excessive Label Content

                      Cause

                      • Inefficient delabeling

                      Решение

                      • Upgrade delabeler rotor design
                      • Increase label removal efficiency

                       

                      Problem 2: High Moisture Content

                      Cause

                      • Insufficient drying capacity

                      Решение

                      • Add thermal drying stage
                      • Optimize dewatering speed

                       

                      Problem 3: PVC Contamination

                      Cause

                      • Poor manual sorting

                      Решение

                      • Install optical sorting equipment
                      • Improve inspection procedures

                       

                      Problem 4: Low Flake Purity

                      Cause

                      • Inadequate washing process

                      Решение

                      • Increase hot washing retention time
                      • Optimize friction washing parameters

                       

                       

                      PET Bottle-to-Bottle Recycling Process Flow

                      PET Bottle Bales  ➡  Bale Breaking  ➡  Sorting  ➡  Delabeling  ➡  Crushing  ➡  Float-Sink Separation  ➡  Hot Washing  ➡  Friction Washing  ➡  Rinsing  ➡  Dewatering  ➡  Thermal Drying  ➡  High-Quality PET Flakes

                       

                       

                      ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ

                      What moisture level is required for PET flakes?

                      Most PET recyclers target moisture below 1%. Food-grade applications often require below 0.5%.

                      Can PET bottle caps be recycled together with PET bottles?

                      Yes, but they must be separated during float-sink separation because PE and PP have lower densities than PET.

                      Why is PVC contamination dangerous?

                      Even small amounts of PVC can cause PET degradation during extrusion and significantly reduce product quality.

                      Каков идеальный размер ПЭТ-чешуек?

                      Most PET washing lines produce flakes between 12 mm and 16 mm for optimal washing and reprocessing performance.

                       

                       

                      Streamline Eco Tech Решение

                      Streamline Eco Tech specializes in PET bottle recycling equipment and complete PET washing line solutions. Our systems integrate bale breakers, label removers, sorting platforms, crushers, float-sink separation tanks, hot washing units, dewatering machines, and drying systems to produce high-purity PET flakes for bottle-to-bottle recycling, fiber production, and other circular economy applications. Equipment configurations can be customized according to material conditions, contamination levels, and production capacities ranging from 500 kg/h to 6000 kg/h.