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
| パラメータ | High-Quality Standard |
| PVC Content | < 50 ppm |
| 水分含有量 | < 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
- 金属
- ガラス
- 論文
- 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.
一般的な出力サイズ：
- 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:
| 素材 | 密度 | 結果 |
| PP | 0.90 g/cm³ | フロート |
| PE | 0.92～0.96 g/cm³ | フロート |
| PET | 1.34～1.39 g/cm³ | 流し台 |
| PVC | 1.30～1.50 g/cm³ | 流し台 |
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:
| パラメータ | 範囲 |
| 水温 | 80～95°C |
| 保持時間 | 15～30分 |
| 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
- 有機汚染物質
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:
- 遠心脱水機
- Thermal Drying System
Target moisture:
- 1%以下
- 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 | 影響 |
| PVC | PET degradation |
| 金属 | Equipment damage |
| ラベル | 黒い斑点 |
| 接着剤 | ゲルの形成 |
| 水分 | Hydrolysis |
| Organics | 臭いの問題 |
よくある問題と解決策
Problem 1: Excessive Label Content
Cause
- Inefficient delabeling
ソリューション
- Upgrade delabeler rotor design
- Increase label removal efficiency
Problem 2: High Moisture Content
Cause
- Insufficient drying capacity
ソリューション
- Add thermal drying stage
- Optimize dewatering speed
Problem 3: PVC Contamination
Cause
- Poor manual sorting
ソリューション
- Install optical sorting equipment
- Improve inspection procedures
Problem 4: Low Flake Purity
Cause
- Inadequate washing process
ソリューション
- 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
よくあるご質問
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.
PETフレークの理想的な粒径はどれくらいですか？
Most PET washing lines produce flakes between 12 mm and 16 mm for optimal washing and reprocessing performance.
ストリームライン・エコ・テック ソリューション
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.
よくある質問
PET洗浄ラインとは何ですか？また、どのような役割を果たすのでしょうか？
PET洗浄ラインでは、使用済みボトルを洗浄し、ペレット化の準備が整った高温洗浄済みフレークに加工します。工程には通常、ラベル剥離、冷水洗浄および温水洗浄、摩擦洗浄、すすぎ、分離、乾燥が含まれます。
高温洗浄と低温洗浄――どちらを選べばいい？
苛性ソーダを用いた高温洗浄は、接着剤、油分、残留物をより効果的に除去できるため、食品グレードや高付加価値のPETにはこの方法が推奨されます。低温洗浄はエネルギー消費が少なく、軽度の汚染に適しています。適切な選択は、投入原料や最終市場によって異なります。
洗濯用ロープは、どのような不純物を取り除く必要があるのでしょうか？
ラベルや接着剤、食品や油の残留物、キャップやリング、そして異物のプラスチックや金属など。優れたラインは、洗浄、密度選別、金属除去を組み合わせて、フレークの純度基準を満たします。