Application of HDPE in Industrial Packaging

HDPE (high-density polyethylene), as a branch of the polyethylene family with high crystallinity (70% -85%) and high density (0.941-0.965g/cm ³), has become one of the preferred materials in the industrial packaging field due to its excellent mechanical strength, chemical corrosion resistance, environmental aging resistance, and processing flexibility. Its performance meets the core requirements of industrial packaging for "load-bearing and pressure resistance, leak prevention and anti-corrosion, recycling and reuse, and controllable cost", and is widely used in storage and logistics links in multiple industries such as chemical raw materials, building materials, mechanical components, electronic components, etc. With the transformation of industrial logistics towards intensification and greening, HDPE has further consolidated its core position in industrial packaging through modification, upgrading, and structural innovation.

1、 The core feature of HDPE adapted industrial packaging: precise matching of performance and scene

Industrial packaging needs to deal with complex challenges such as raw material corrosiveness, transportation bumps and collisions, storage stacking pressure, and extreme environmental storage. The physical and chemical properties of HDPE precisely form targeted solutions, and its advantages far exceed ordinary plastic, metal, and wooden packaging materials.

1. Excellent mechanical strength: the foundation guarantee for bearing and protection

The primary requirement for industrial packaging is to protect the contents from damage and maintain structural stability. The mechanical properties of HDPE can meet the strength requirements of multiple scenarios

High impact resistance and tensile strength: HDPE has a tensile strength of up to 20-30MPa, a notch impact strength (23 ℃) of 20-50kJ/m ², and a low-temperature (-40 ℃) impact strength of 10-20kJ/m ², far exceeding LDPE (low-density polyethylene) and PP (polypropylene). When the packaging container or pallet is impacted or dropped during transportation (without damage from a 1.5m height drop), it can effectively buffer the impact force and prevent the contents from leaking or being damaged; When stacked and stored, it can withstand a stacking weight of 5-8 layers (a single layer can carry more than 500kg), suitable for large-scale storage of industrial raw materials.

Balance of rigidity and toughness: HDPE combines rigidity and toughness, neither brittle like PS (polystyrene) nor easily deformed like soft PVC. For example, a 20L HDPE chemical drum can withstand a hanging weight of 30kg at the handle without breaking when filled with liquid; HDPE pallets will not undergo permanent deformation even when the edges are compressed during forklift lifting, ensuring their reusability.

Strong wear resistance: HDPE has a Shore D hardness of 60-70, and its surface wear resistance is better than PP and wooden materials. The turnover boxes and pallets made of HDPE are not easily scratched or damaged during frequent handling and friction, and their service life can reach 3-5 years (wooden pallets are only 1-2 years), reducing the cost of repeat purchases.

2. Excellent chemical stability: suitable for corrosive industrial raw materials

More than 30% of industrial raw materials have acidity, alkalinity, oiliness, or corrosiveness, and the chemical inertness of HDPE can achieve safe packaging:

Acid and alkali corrosion resistance: HDPE has excellent resistance to acid and alkali solutions with concentrations below 50%, such as sulfuric acid, hydrochloric acid, nitric acid, and concentrations below 30%, such as sodium hydroxide and potassium hydroxide, without dissolution, swelling, or degradation. For example, a 25L HDPE drum containing hydrochloric acid, after being stored at room temperature for 12 months, has no leakage or deformation of the drum body and a weight loss rate of less than 0.5%.

Oil resistance and solvent stability: HDPE has extremely low permeability to common industrial solvents such as mineral oil, vegetable oil, ethanol, acetone, etc. When gasoline, diesel and other fuels are stored in HDPE containers, the permeability is ≤ 0.1g/(m ² · 24h), much lower than LDPE's 1.5g/(m ² · 24h), which can effectively prevent solvent evaporation or leakage pollution.

Chemical adsorption resistance: HDPE has a low surface porosity, which makes it difficult to adsorb chemical substances from raw materials. When packaging, recycling, and cleaning, residues are easily removed, making it easy to reuse or comply with regulations. It is especially suitable for packaging materials such as coatings and inks that are prone to adsorption.

3. Strong resistance to environmental aging: suitable for complex storage and transportation conditions

Industrial logistics often involves outdoor stacking, long-distance transportation, extreme temperature and humidity environments. The weather resistance of HDPE ensures packaging stability:

High and low temperature resistance performance: HDPE can be used in a temperature range of -40 ℃ to 60 ℃, and can withstand high temperatures of up to 80 ℃ in the short term. When stored outdoors in the northern winter (-30 ℃), the packaging will not be brittle or cracked; In the southern summer (50 ℃) carriage transportation, it will not soften or deform, and is suitable for nationwide cross regional logistics.

Anti UV aging: By adding modifiers such as carbon black and UV absorbers, the anti UV aging performance of HDPE can be improved by 5-10 times. After 12 months of outdoor exposure, the tensile strength retention rate is still ≥ 80%, making it suitable for packaging raw materials such as building coatings and outdoor chemicals that require long-term outdoor storage.

Water resistance and moisture resistance: The water absorption rate of HDPE is only 0.01% -0.02%, almost not absorbing water. The packaging containers or films made of HDPE can effectively block water vapor, avoiding moisture absorption materials such as cement, gypsum powder, electronic components, etc. from being affected by moisture, clumping or short circuiting damage.

4. Processing and cost advantages: supporting large-scale industrial applications

The demand for industrial packaging is high and the specifications are diverse. The processing flexibility and cost advantages of HDPE meet the needs of large-scale production

Rich molding process: HDPE can be made into different forms of packaging products through processes such as blow molding, injection molding, extrusion, and rotational molding. Blow molding process produces 1-200L plastic drums and cans; Manufacturing pallets and turnover boxes using injection molding technology; Extrusion process for producing films, pipes, and woven bags; Roll molding technology is used to produce large storage tanks (over 500L), covering almost all forms of industrial packaging requirements.

Cost and energy consumption are controllable: HDPE's raw material cost is 30% lower than PET and 80% lower than stainless steel, and its processing energy consumption is low (forming temperature 130-135 ℃, lower than PP's 160-170 ℃); At the same time, the weight of HDPE packaging is only 1/5 of metal packaging and 1/3 of wooden packaging of the same capacity, which can reduce transportation energy consumption by 20% -30% and significantly control the overall cost of enterprises.

Strong recyclability: HDPE belongs to the category of recyclable plastics (recycling label "No. 2"). After recycling, it can be physically regenerated into recycled HDPE (rHDPE), which is used for packaging or pallets that do not come into direct contact with corrosive raw materials. The recycling rate can reach over 85%, in line with the policy orientation of "reducing carbon and waste" in the industrial field.

2、 Core application scenario of HDPE in industrial packaging: protection system for all categories of industrial materials

The application of HDPE in industrial packaging accounts for over 40%. According to the packaging form and content characteristics, it can be divided into three sub categories: container, film and weaving, and pallet and turnover. Each application is optimized for the storage and transportation needs of industrial materials.

1. Container packaging: the main carrier of liquid and powdered industrial raw materials

Container packaging is the most common application form of HDPE in industrial packaging, accounting for over 50%. According to capacity and process, it can be divided into small barrels, medium-sized containers, and large storage tanks, suitable for different volumes of industrial raw materials:

Small bucket (1-25L): produced using blow molding technology, mainly used for small and medium-sized batch liquid raw materials such as coatings, inks, adhesives, cleaning agents, pesticides, etc. The core advantages of this type of container are: firstly, good sealing performance, using a screw cap and silicone sealing ring design, with a leakage rate of less than 0.01%, which can prevent volatile raw materials from evaporating or leaking; Secondly, it is easy to handle, with anti slip patterns and handles on the barrel body. The weight of a single barrel (including its contents) is controlled within 25kg, making it convenient for manual handling; Thirdly, the labeling is clear, and the barrel body can be directly printed with information such as raw material names, specifications, and hazardous material labels, in compliance with industrial safety standards. For example, 10L interior wall paint buckets from paint brands such as Nippon Paint and Dulux are made of HDPE material, which is resistant to solvent corrosion and has strong leak resistance.

Medium sized container (25-200L): made through hollow blow molding or rotational molding process, suitable for medium and large batch materials such as chemical raw materials, lubricants, food additives, etc. The 200L HDPE barrel is a typical representative, with a barrel thickness of 3-5mm, equipped with galvanized steel hoops and flange covers, capable of withstanding an internal pressure of 0.1MPa, suitable for containing liquid chemical raw materials; Some large barrels are equipped with leak proof inner liners, which are double sealed with "barrel lid+inner liner lid" to further enhance the leak proof level. They are used for packaging highly toxic or high-value raw materials. In addition, 50L HDPE square drums have become the mainstream packaging for building adhesives, latex paints, and other raw materials due to their ability to save storage space (stacking up to 8 layers).

Large storage tanks (over 500L): produced using rotational molding technology, with a capacity of up to 10-50m ³, used for factory raw material storage or wastewater treatment. The advantages of HDPE large storage tanks are: firstly, they have strong corrosion resistance and can store highly corrosive solutions such as sulfuric acid, nitric acid, and sodium hydroxide without the need for additional anti-corrosion coatings; Secondly, it has good impact resistance and can withstand external collisions or internal liquid impacts without breaking; Thirdly, it is easy to install, weighing only 1/10 of the same capacity stainless steel storage tank, and can be assembled or lifted as a whole on site. For example, small-scale chemical plants commonly use 10m ³ HDPE storage tanks to store hydrochloric acid, with a service life of over 10 years and a cost only one-third of stainless steel storage tanks.

2. Film and woven packaging: protective barriers for solid and bulk materials

HDPE is made into thin films or woven materials through extrusion technology, which are used for moisture-proof, dust-proof, and container packaging of solid materials, mainly including thin films, woven bags, and composite packaging:

HDPE film packaging: divided into single-layer film and composite film. Single layer film (thickness 0.05-0.2mm) is used for moisture-proof packaging of mechanical and electronic components, forming a sealed bag through heat sealing to block water vapor and dust; The composite film (HDPE/LLDPE blend film) has a thickness of 0.1-0.3mm and a tear strength of up to 50N/mm. It is used for packaging bulk powders such as cement and gypsum powder, and is made into an "inner film bag" for use with an outer woven bag. Its moisture resistance is better than that of traditional single-layer woven bags. For example, the 50kg product of Conch Cement adopts a "HDPE inner membrane+PP woven bag" structure, which can effectively prevent cement from absorbing moisture and clumping.

HDPE woven bag: woven from HDPE flat wire, with high strength and wear resistance, it is the core packaging of industrial bulk materials (accounting for more than 60% of the woven bag market). According to the load-bearing requirements, it can be divided into ordinary woven bags (load-bearing 25-50kg) and container bags (load-bearing 500-2000kg): ordinary woven bags are used to package plastic particles, fertilizers, feed, etc., and the bag body can be printed with moisture-proof, sunscreen and other warning signs; Container bags (also known as ton bags) adopt a "base cloth+sling" structure, with a sling strength of up to 5000N. When used in conjunction with forklifts or cranes, they are suitable for handling bulk materials such as mineral powder and plastic slices in ports and docks.

Composite woven packaging: HDPE woven fabric is combined with film and aluminum foil to form structures such as "woven fabric/PE film" and "woven fabric/aluminum foil/PE film", which have both strength and barrier properties. The "woven fabric/PE film" composite bag is used to package easily hygroscopic powders such as coating powders and dyes, with a moisture resistance 3-5 times higher than ordinary woven bags; The "woven fabric/aluminum foil/PE film" composite bag is used for packaging raw materials that require high light and oxygen resistance (such as certain chemical catalysts). The aluminum foil layer can block more than 99% of ultraviolet rays and oxygen, extending the shelf life of the raw materials.

3. Pallets and turnover packaging: the supporting core of logistics transportation

HDPE pallets and turnover boxes are the "mobile platforms" of industrial logistics, accounting for 30% of the industrial pallet market. They replace traditional wooden pallets with durability and reusability

HDPE plastic pallets: produced through injection molding or blow molding processes, divided into double-sided, single-sided, grid type, and flat type, suitable for different materials and handling equipment. The double-sided pallet can support up to 1500kg and is suitable for two-way forklifts and multi-layer stacking; Grid type trays have good breathability and are used for packaging wet materials (such as wet chemical intermediates); The flat tray has a smooth surface and is suitable for placing electronic components, precision parts, and other easily scratched products. The core advantages of HDPE pallets are long service life (3-5 years, while wooden pallets only have 1 year), easy cleaning (washable or steam disinfectable), and high recycling value, especially suitable for industries with high hygiene requirements such as food processing and pharmaceuticals. For example, Coca Cola's syrup raw materials are transported using HDPE mesh pallets, which can be reused more than 200 times.

HDPE turnover box: injection molded, divided into covered, uncovered, and partitioned types, used for internal raw material turnover and component storage in factories. The impact resistance of turnover boxes is strong, and they do not break when dropped from a height of 1.2m, making them suitable for frequent handling in assembly line operations; Some turnover boxes are equipped with locks or stacking structures to prevent the lid from falling off or the box from tipping over during transportation; The turnover box with partition can store different specifications of components (such as screws and nuts) in different zones to avoid mixing. For example, automotive parts factories commonly use HDPE turnover boxes with partitions to store stamped parts. The partitions can be customized according to the size of the parts to protect them from collision damage.

Logistics auxiliary packaging: HDPE is also used to make cushioning materials, anti slip pads, strapping, etc. for logistics. HDPE buffer blocks are made by foaming, with a density of 0.1-0.3g/cm ³, and are used for packaging precision machinery (such as machine tool components) to cushion impact forces; The surface of HDPE anti slip pad has anti slip patterns, which can prevent goods from sliding when laid on pallets; The tensile strength of HDPE strapping can reach 15MPa, replacing traditional steel strips. It is lightweight and not easy to rust, and is used for bundling and fixing containerized goods.

3、 Modification, upgrading and innovative application of HDPE in industrial packaging

With the upgrading of the demand for "functionalization, lightweighting, and greenization" of packaging in industrial logistics, HDPE continuously expands its application boundaries through modification technology and structural innovation, and develops characteristic products that are suitable for high-end industrial scenarios.

1. Modified HDPE: meets special industrial needs

By adding functional fillers or blending modifications, HDPE can achieve special properties and adapt to high demand industrial scenarios:

Reinforced and Toughened HDPE: Adding glass fiber (content 10% -30%) to make reinforced HDPE, the tensile strength is increased to 40-50 MPa, and the bending strength is increased to 60 MPa. It is used to make large pallets or storage tanks with high load-bearing requirements, such as heavy-duty HDPE pallets with a load-bearing capacity of 2000 kg; Adding EPDM (ethylene propylene diene monomer rubber) to make toughened HDPE, the impact strength at low temperature (-40 ℃) is increased to over 30kJ/m ², and it is used for outdoor packaging in cold northern regions, such as transportation barrels for chemical raw materials in winter.

Antibacterial HDPE: The turnover box or tray made by adding antibacterial agents such as silver ions and zinc oxide can inhibit the growth of microorganisms such as Escherichia coli and Staphylococcus aureus. It is used for packaging raw materials with high hygiene requirements such as food additives and pharmaceutical intermediates, reducing the risk of microbial contamination. For example, the raw material turnover boxes in pharmaceutical factories are made of antibacterial HDPE, which can reduce the frequency of cleaning and disinfection and improve production efficiency.

Anti static HDPE: Adding carbon black, anti-static agents, etc. to reduce the surface resistance of HDPE to 10 ⁶ -10 ⁹ Ω, used for packaging electronic components (such as chips, circuit boards) to prevent component damage caused by static electricity accumulation. Anti static HDPE trays can effectively release static electricity and protect precision electronic components in the logistics process of electronic factories.

2. Structural innovation: improving packaging performance and efficiency

By optimizing the packaging structure design, HDPE packaging can achieve "upgraded protection, convenient use, and optimized space":

Multi layer co extrusion container: using the "HDPE/EVOH/HDPE" multi-layer co extrusion process, EVOH (ethylene vinyl alcohol copolymer) is used as the intermediate barrier layer, and the oxygen barrier rate is 10-20 times higher than that of single-layer HDPE. It is used for packaging chemical raw materials that are sensitive to oxygen (such as certain polymer monomers), extending the storage shelf life. For example, the shelf life of acrylic monomers packaged in 25L multi-layer co extruded HDPE drums has been extended from 6 months to 12 months.

Folding turnover box: HDPE folding boxes can be folded to one-third of their original volume when empty, greatly saving storage and transportation space (reducing empty box transportation costs by 60%), suitable for industries such as e-commerce and express delivery that require frequent recycling of empty boxes. The hinge part of the folding box is made of reinforced HDPE, with a service life of over 500 folds and excellent fatigue resistance.

Integrated packaging system: HDPE containers, trays, and cushioning materials form an integrated packaging, such as the combination of "200L HDPE drums+HDPE trays+HDPE fixing straps". The drum body and tray are fixed by card slots to prevent the drum body from tipping over during transportation; The fixed strap can be reused, replacing disposable bundling straps and reducing the generation of packaging waste.

3. Green application: responding to the demand for "dual carbon" policies

Under the promotion of the "carbon peak and carbon neutrality" policy, HDPE packaging is developing towards the direction of "recycling, biobased, and biodegradable":

Industrial application of recycled HDPE (rHDPE): Through the "sorting cleaning melting filtration" process, the recycled HDPE packaging can be made into rHDPE, which is used to produce trays, turnover boxes, and outer packaging drums for non direct contact corrosive raw materials. For example, after purification, recycled HDPE coating drums can be made into industrial turnover boxes, with mechanical properties reaching over 80% of native HDPE and a cost reduction of 30%. At present, the usage rate of rHDPE in industrial packaging in Europe has reached 40%, and it is gradually being promoted in China.

Research and application of bio based HDPE: Bio based HDPE made from biomass such as sugarcane and corn has a carbon footprint 40% -60% lower than traditional HDPE, and its performance is basically the same as traditional HDPE. It can be used to make industrial woven bags, trays, etc. For example, the bio based HDPE produced by Braskem in Brazil has been used in industrial raw material packaging barrels for Coca Cola, achieving "fossil based substitution".

Exploration of Biodegradable HDPE: Adding PBAT (polybutylene adipate terephthalate), starch and other degradable components to HDPE, the resulting packaging can degrade for 6-12 months under industrial composting conditions and is used for disposable industrial packaging (such as cushioning packaging for small components) to reduce plastic pollution.