Overview
Low-Density Polyethylene (LDPE) is a semi-rigid, translucent thermoplastic produced via free radical polymerization of ethylene under high pressure. It was the first grade of polyethylene developed in 1933 by Imperial Chemical Industries (ICI), revolutionizing the plastics industry. LDPE is characterized by its branched molecular structure, which gives it lower density and crystallinity compared to HDPE (High-Density Polyethylene). As a commodity plastic, LDPE accounts for approximately 20% of global polyethylene production. Its combination of processability, chemical resistance, and flexibility makes it indispensable for applications ranging from food packaging to agricultural films. The material is FDA-compliant for food contact and widely recycled under resin identification code #4.
Physical and Chemical Properties
LDPE exhibits unique mechanical properties including high impact strength (even at -70°C) and elongation at break exceeding 300%. Its branched polymer chains prevent tight packing, resulting in a density range of 0.910–0.940 g/cm³ – the lowest among commercial polyethylenes. The material shows excellent resistance to acids, alkalis, and alcohols but is susceptible to strong oxidizing agents. Thermal properties include a relatively low melting point (105–115°C) and continuous use temperature up to 80°C. Electrical properties are outstanding, with volume resistivity >1016 Ω·cm and dielectric strength around 20 kV/mm. Processing typically involves blown film extrusion (for films) or injection molding (for rigid parts), with melt flow index (MFI) values ranging from 0.2–50 g/10min depending on application requirements.
Main Applications
Approximately 55% of LDPE production is used for packaging films, including stretch wrap, grocery bags, and garment covers. Its exceptional clarity (when processed properly) makes it ideal for bakery and produce packaging. In consumer goods, LDPE appears in squeeze bottles (for honey, mustard), toys, and container lids due to its flexibility and food-grade compliance. Industrial applications include wire and cable insulation (utilizing its dielectric properties), agricultural films (greenhouse covers, mulch films), and corrosion-resistant linings. Medical applications involve sterilization wraps and tubing. Recent innovations include LDPE nanocomposites with enhanced barrier properties for specialty packaging and UV-stabilized grades for outdoor applications.
Safety and Storage
LDPE is generally recognized as safe (GRAS) for food contact applications and is non-toxic in solid form. However, processing at high temperatures (>200°C) may release volatile organic compounds (VOCs) requiring adequate ventilation. The material burns readily (LOI 17–18%) and produces dripping flames – flame-retardant additives are available for critical applications. Proper storage involves keeping LDPE pellets or products in original packaging below 40°C, away from UV exposure to prevent oxidative degradation. Bulk storage silos should have nitrogen purging systems for premium-grade resins. Shelf life is typically 12–24 months when stored correctly. Recycled LDPE must be carefully evaluated for contamination if used in food-contact applications.
B2B Procurement Guide
Industrial buyers should specify these key parameters: Melt Flow Index (MFI) – lower values (0.2–2) for extrusion, higher (20–50) for injection molding; density (target 0.918–0.932 g/cm³ for standard LDPE); and additive package (UV stabilizers, slip agents, etc.). Food-grade purchases require FDA or EU compliance documentation. Major global suppliers include ExxonMobil (Exceed™), Dow (LDPE™), and LyondellBasell (Lupolen™). Price fluctuations track crude oil and ethylene feedstock costs – consider long-term contracts during market lows. For sustainable sourcing, inquire about post-consumer recycled (PCR) content options (typically 30–100% recycled). Quality certifications to verify include ISO 9001 and ISO 14001 for environmental management.
Related Manufacturers
- 主营：单梁起重机、龙门吊、浇铸机械手、ldp型电动单梁起重机、桥式起重机、龙门架、电缆卷筒、不锈钢抓斗、悬臂吊、液压夹轨器、手动夹轨器、双梁桥式起重机、单梁桥式起重机、kbk起重机、电磁吸盘、电动地平车、电动葫芦、真空负压吸盘、减速机、行车轮、弧形轨道
- 主营：放大器、检测器、滤波器、调制器、发射器、接收器、衰减器、解调器、变压器、收发器、偏置器、振荡器、rfid天线、终端负载、隔直流器、微波射频、集成电路、同轴开关、接入监控ic、频率综合器、射频适配器、定向耦合器、耦合器电桥、多路复用器、rfid读取模块
- 主营：龙门吊、架桥机、行车行吊、冶金铸造起重机、桥式起重机、集装箱龙门吊、门式起重机、抓斗起重机、集装箱跨运车、竖井龙门吊、欧式起重机、防爆起重机、造船龙门吊、轮胎式起重机、电磁桥式起重机、提梁机、运梁车、游艇搬运机、门座式起重机、自平衡架桥机
- 主营：接触器、变频器、继电器、断路器、控制器、光电开关、接近开关、空气开关、交直流开关、过载保护器、漏电保护器、触摸屏、气缸、传感器、电磁阀、编码器、温控器、伺服电机、液压马达、阀门定位器、模块、软启动器、开关电源、浪涌保护器、不间断电源
- 主营：单梁桥式起重机、双梁桥式起重机、单梁门式起重机、钢丝绳电动葫芦、龙门吊、无轨龙门架、卷扬机、环链电动葫芦、悬臂吊、电动平车、货梯、电动吸盘、抓斗、行车、5吨行车、10吨电动葫芦
- 主营：菲尼克斯
- 主营：电动单梁起重机、龙门吊、双梁桥式起重机、ldp型电动桥式、导轨货梯、起重设备、行吊维保、电动葫芦、电动升降货梯、冶金起重机、防爆起重机、桥式起重机、集装箱装车机、自动装车机、智能装车机、集装箱翻转机、集装箱液压装货机
- 主营：phoenix菲尼克斯防雷器、DEHN防雷器、obo防雷器
- 主营：流化床、上料机、振荡筛、冻干机、粉碎机、振动筛、混料机、干燥机、敲击锤、整粒机、造粒机、干化机、打粉机、破碎机、振动方、搅拌机、制粒机、烘干机、烘干箱、包衣机、混合机、zb真空耙、造粒干燥、恒温烘箱、热风循环
- 主营：钢丝绳葫芦、单梁/龙门起重机、双梁起重机、无轨龙门架、电动卷扬机、慢速绞车、起重吊索具、KBK轻型起重机、悬臂起重机、环链电动葫芦、电动平车、货梯、抓斗
- 主营：电磁阀、压力开、传感器、编码器、变频器、继电器、控制器、液压泵、液位计、变送器、伺服电机、光电开关、电源模块、控制模块
- 主营：齿轮泵、机械阀、机电液、气动阀、hpe6310hp、电磁阀、迷你缸、液压泵、回转缸、双联泵、high-tech、放大器、气油压、止逆阀、调压器、溢流阀、逻辑阀、传感器、换向阀、调节阀、油压阀、液动阀、不二越、调压阀、手动阀
- 主营：飞利浦LED灯具、飞利浦LED投光灯、飞利浦LED筒灯、飞利浦日光灯、欧普照明LED灯具
- 主营：ad2s83apz、ad2s80aud、ad2s99apz、adi模数、ag203-63g、njstd261a、缓冲器、解码器、lsm9ds1tr、ag201-63g、调节器、连接器、njstd262a、分频器、陀螺仪、处理器、驱动器、adi电源、hmc347arf、加速计、放大器、稳压器、锁相环、控制器、以太网
- 主营：PA66原料、PA6原料、POM原料、PA尼龙