Application and Development of Plastic Machinery and Equipment in the Production of Plastic Food Packaging
Publish Time: 2025-09-29
Food packaging is a core component of the modern food industry. Its functions extend beyond product protection to extend shelf life, enhance the consumer experience, and promote brand marketing. Among numerous packaging materials, plastic has become the mainstream choice for food packaging due to its lightweight, high barrier properties, plasticity, and cost advantages. According to statistics, plastic accounts for over 60% of the global food packaging market, encompassing a variety of forms such as bottles, bags, boxes, and cans. The core force supporting this industry is plastic machinery and equipment, represented by blow molding machines, injection molding machines, and positive and negative pressure molding machines. This article will systematically review the application technologies, process innovations, and industry development trends of plastic machinery and equipment in food packaging production.I. Core Functions and Market Demand for Plastic Food Packaging1.1 Basic Function: Protection and IsolationThe primary function of plastic food packaging is to create a physical barrier to prevent food from being degraded by external factors such as oxygen, water vapor, microorganisms, and light. For example, high-barrier PET bottles can control oxygen permeability to less than 2cc/(m²·24h), extending the shelf life of easily oxidized foods like juice to 12 months. Aluminum-plastic composite film, through vacuum extraction technology, can reduce the oxygen content of nuts to below 0.5%, effectively preventing oil and fat oxidative rancidity.1.2 Logistics Optimization: Lightweighting and StandardizationPlastic packaging has a density that is only one-fourth that of glass and one-sixth that of metal, significantly reducing transportation energy consumption. For example, a 500ml beverage bottle made of PET is 82% lighter than a glass bottle, reducing shipping costs per box by 35%. Furthermore, standardized specifications (such as 12oz and 16oz standard bottles) maximize storage space utilization and, when combined with automated sorting systems, improve logistics efficiency by over 40%.1.3 Upgrading the Consumer Experience: Functionality and InteractivityModern food packaging has moved beyond traditional protective functions to become more intelligent and personalized. For example, Lemobao uses long-film vectoring technology to achieve an instant-tear opening feature, resolving the pain point of traditional packaging requiring scissors. Some high-end yogurt packaging features an easy-tear lid design, coupled with AR scanning technology. Consumers can scan the packaging with their phones to access product traceability information and cooking tutorials, enhancing brand loyalty.II. Technical System and Process Innovation of Plastic Machinery and Equipment2.1 Blow Molding Machines: Core Equipment for Hollow Container ManufacturingBlow molding machines use air pressure forming technology to produce hollow containers such as bottles, cans, and barrels. The process can be categorized into three types: extrusion blow molding, injection blow molding, and stretch blow molding.Extrusion blow molding: Suitable for large-capacity containers (such as 5L cooking oil drums). Molten PE/PP is extruded into a tubular parison using a single-screw extruder. The parison is then expanded by air blowing and cooled to set the shape. This process requires low equipment investment, but the wall thickness uniformity of the product is poor (±15%).Injection blow molding: Mostly used for small-volume precision containers (such as 250ml medicine bottles). The injection molding machine first forms a parison with a neck, which is then transferred to a blow mold for secondary molding. The product wall thickness accuracy can reach ±3%, but mold costs are relatively high.Stretch blow molding: Incorporating biaxial stretching technology improves the transparency of PET bottles by 30% and their impact strength by 50%. A typical application is a 500ml mineral water bottle, where the wall thickness is reduced from 0.4mm to 0.25mm, reducing material consumption by 35%.2.2 Injection Molding Machines: Precision Manufacturing of Rigid PackagingInjection molding machines use high-pressure injection to inject molten plastic into a closed mold to produce rigid packaging such as boxes, lids, and trays. Their technological breakthroughs include:Multi-component injection molding: Using two-color injection molding technology, PP and TPE materials are integrally molded to produce food containers with soft seals, improving sealing by 200%.Micro-foam Injection Molding: Using supercritical CO₂ foaming technology, a uniform closed-cell structure is created inside the packaging, reducing weight by 15% while improving thermal insulation by 10%.High-speed Servo Drive: The fully electric injection molding machine has a response speed of 0.1ms. Combined with in-mold labeling (IML) technology, it can achieve continuous production at 120 cycles per minute, meeting the scale-up requirements of fast food packaging.2.3 Positive and Negative Pressure Molding Machine: An Efficient Solution for Flexible PackagingPositive and negative pressure molding machines combine thermoforming and vacuum adsorption technologies to produce flexible containers such as blister trays and modified atmosphere packaging. Their innovative applications include:High-barrier Film Molding: Using negative pressure adsorption, PVDC-coated film is bonded to the mold to produce breathable film packaging for chilled meat. The oxygen transmission rate is controlled at 5cc/(m²·24h) while maintaining a low CO₂ release rate, extending the shelf life to 21 days.Multi-chamber integrated molding: Utilizing a combined positive pressure blow molding and negative pressure adsorption process, this double-compartment lunch box achieves a partition seal strength of 1.2 N/mm, preventing soup leakage.Intelligent Temperature Control System: Utilizing infrared heating and PID temperature control technology, the film heating time is reduced from 8 seconds to 3 seconds, and the molding cycle is compressed to 1.5 seconds per piece, increasing efficiency by 40%.III. Industry Development Trends and Challenges3.1 Green Transformation: Degradable Materials and the Circular EconomyFaced with the EU's "Plastics Strategy" and China's "Dual Carbon" goals, the industry is accelerating its transition to bio-based materials. For example, PBAT/PLA blends are already used in the production of degradable shopping bags, boasting a tensile strength of 25 MPa, meeting supermarket load-bearing requirements. Furthermore, chemical recycling technology can recycle discarded PET bottles into food-grade rPET pellets, reducing the carbon footprint by 70%.3.2 Intelligent Upgrade: Industry 4.0 and Flexible ProductionSmart factories connect devices through the Internet of Things (IoT), for example:Injection molding machine cluster control systems: Real-time monitoring of parameters such as screw speed and melt temperature, automatically adjusting the process to reduce scrap (target <0.5%).AI visual inspection: Utilizing deep learning algorithms to identify packaging surface defects (such as scratches and bubbles), with an inspection speed of up to 200 pieces/minute and an accuracy rate of 99.2%.Flexible production lines: Rapid mold change technology (mold change time <15 minutes) enables the compatible production of multiple product categories, including bottles, boxes, and bags, on the same production line.3.3 Safety Enhancement: Compliance and Risk ControlFood contact materials must comply with the GB 4806 series of standards and FDA 21 CFR 177. Industry innovations include:Fluorine-free coating technology: An alternative to traditional PFAS-containing oil-repellent films for potato chip packaging, with a migration level of <0.01 mg/kg.Nanosilver antimicrobial packaging: Ag⁺ is loaded onto the surface of PE film via a sol-gel method, achieving a 99.9% inhibition rate against E. coli and extending the shelf life of baked goods.Blockchain traceability system: Incorporating RFID chips enables full data traceability from raw materials to finished product, meeting the requirements of the EU General Food Directive.IV. Typical Case Studies4.1 Case 1: The Lightweight Revolution of PET BottlesA beverage company optimized its stretch blow molding process, reducing the wall thickness of its 500ml bottle from 0.38mm to 0.28mm, reducing the weight of each bottle by 22%. Combined with a microstructured cap design (with a 0.15mm sealing lip thickness), the company saves 1,200 tons of PET raw materials annually and reduces carbon emissions by 3,800 tons while maintaining a compressive strength of 0.6MPa.4.2 Case 2: A Breakthrough in Modified Atmosphere Packaging for FreshnessA meat processing company used positive and negative pressure molding machines to produce high-barrier trays. Combined with the use of an 80% N₂ + 20% CO₂ gas mixture, this reduced the total bacterial count of fresh pork from 10⁵ CFU/g to 10³ CFU/g, extending shelf life from 7 days to 15 days, and reducing logistics loss from 12% to 3%.4.3 Case 3: Commercialization of Degradable PackagingA fast food brand partnered with a material supplier to launch a PBAT/starch blend lunch box with a tensile strength of 18 MPa that is fully degradable within 60 days. By optimizing the blow molding process (melt temperature of 165°C and blow-up ratio of 2.5:1), the box's stiffness was increased by 30%, meeting the needs of food delivery.V. OutlookPlastics machinery and equipment are driving the evolution of food packaging towards efficiency, greenness, and intelligence. Over the next five years, the industry will focus on three key areas:Material innovation: Developing high-performance bio-based polymers (such as PHA and PEF) to replace traditional petroleum-based materials;Process breakthroughs: Promoting 3D printing packaging technology to enable personalized customization and on-demand production;System integration: Building a digital platform for the entire "equipment-material-recycling" chain to promote the implementation of a circular economy.As consumers' concerns about food safety and environmental protection continue to grow, plastic machinery and equipment manufacturers need to collaborate closely with brands and material suppliers to continuously empower the upgrading of the food packaging industry through technological innovation.
