Modern flexible packaging composite technology is one of the core pillars of the packaging industry. Solvent-based flexible packaging adhesive and solvent-free flexible packaging adhesive are two main types of adhesives. Due to their different technical characteristics and application fields, they each have their own advantages and disadvantages. The following is an in-depth research of the differences between the two from the perspective of application technology.
Application Difference
1. Scope of application
1.1 Solvent-based flexible packaging adhesive
1.1.1 High-performance scenarios: widely used in packaging for high value-added industries such as food and medicine, such as high barrier structures, multi-layer composite films (PET/AL/PA/CPP, etc.).
1.1.2 Special needs: able to cope with harsh conditions such as high-temperature cooking, freezing, and chemical resistance, suitable for high-demand products such as cooking bags and vacuum packaging bags.
1.1.3 Substrate compatibility: excellent adaptability to special substrates such as metallized films, nylon, PET, and PVDC.
1.2 Solvent-free flexible packaging adhesive
1.2.1 Conventional packaging: mostly used for composite materials with conventional needs such as daily food packaging and daily chemical packaging, such as common two-layer or three-layer structures such as OPP/PE and PET/PE.
1.2.2 Green and environmental protection needs: suitable for enterprises that focus on low carbon emissions and sustainable development, especially markets with strict environmental regulations.
1.2.3 Lightweight packaging: more suitable for thin and simplified flexible packaging design solutions.
2. Environmental performance
2.1 Solvent-based laminating adhesive
2.1.1 VOC emissions: Due to the large amount of volatile organic compounds (VOCs), it will have a certain impact on the environment during the production process, especially in areas that need to strictly comply with environmental protection regulations.
2.1.2 Solvent residue: It is necessary to reduce solvent residue through an efficient drying system, especially in food and drug packaging, where residual solvent may affect safety.
2.2 Solvent-free laminating adhesive
2.2.1 Zero VOC emissions: It does not contain solvents, does not require solvent volatilization and recycling, and is an adhesive that is more in line with the concept of green environmental protection.
2.2.2 Consumer-friendly: Due to the lack of solvent residue, the food safety of the packaging is greatly improved.
3. Production costs
3.1 Solvent-based flexible packaging adhesive
3.1.1 High equipment investment: Dryer and solvent recovery equipment are required, which increases the initial investment.
3.1.2 High energy consumption: The drying process consumes a lot of energy and the operating cost is high.
3.2 Solvent-free flexible packaging adhesive
3.2.1 Low equipment cost: Only a solvent-free composite machine is needed to complete the production, and the equipment investment is low.
3.2.2 Economical operation: No drying process is required, which greatly reduces energy consumption and makes the long-term production cost more competitive.
Technology Difference
1. Solid content and bonding performance
1.1 Solvent-based laminating adhesive
1.1.1 Low solid content: generally 30%-50%, the film is cured by solvent evaporation.
1.1.2 Strong bonding force: suitable for high barrier composite, the bonding strength and durability are better than solvent-free adhesive.
1.2 Solvent-free laminating adhesive
1.2.1 High solid content: close to 100%, cured by chemical reaction (mostly isocyanate and hydroxyl reaction).
1.2.2 Limited applicability: good performance in ordinary packaging applications, but slightly insufficient durability under high temperature cooking or other extreme conditions.
2. Process complexity
2.1 Solvent-based flexible packaging adhesive
2.1.1 Multiple processes: coating, drying, and composite processes are required. Drying speed and temperature control have a great impact on the final performance.
2.1.2 Fine operation: high requirements for equipment, especially in high-speed production lines, require precise control of drying and composite parameters.
2.2 Solvent-free flexible packaging adhesive
2.2.1 Simple and efficient: only two steps of coating and composite are required, and the process is significantly simplified.
2.2.2 Fast production: suitable for high-speed composite production lines to further improve production efficiency.
3. Substrate compatibility
3.1 Solvent-based laminating adhesive
3.1.1 Can be used for composites of various substrates, including metal films, high barrier films and other special materials.
3.2 Solvent-free laminating adhesive
3.2.1 It has good adaptability to conventional substrates such as PE, PP, PET, etc., but its adaptability to high surface tension substrates is not as good as solvent-based.
4. Equipment and operation requirements
4.1 Solvent-based flexible packaging adhesive
4.1.1 During the operation, attention should be paid to solvent volatilization, which may cause certain safety hazards, such as fire and poisoning risks.
4.1.2 During storage, attention should be paid to sealing and avoiding light to prevent solvent volatilization and deterioration.
4.2 Solvent-free flexible packaging adhesive
4.2.1 No need to consider solvent safety issues, storage and operation are more convenient.
4.2.2 The process is highly controllable, insensitive to temperature and humidity, and more adaptable.
Development Trend
With the gradual strengthening of environmental protection policies and the increasing demand of consumers for safe packaging, solvent-free flexible packaging adhesives are becoming the mainstream of industry development. However, in the field of high-performance and special demand composites, solvent-based laminating adhesives still have irreplaceable advantages. In the future, the two may show the following development trends:
1. Optimization of solvent-based laminating adhesives: Reduce environmental impact while maintaining high performance characteristics by developing low-VOC or recyclable solvent-based flexible packaging adhesives.
2. Improvement of solvent-free technology: Develop higher strength and more high-temperature resistant solvent-free adhesives to meet high-end applications such as cooking and freezing.
3. Intelligent composite process: Promote the popularization of intelligent composite equipment to make the application of the two adhesives more efficient and accurate.
Summary
Solvent-based flexible packaging adhesives occupy an important position in the high-end packaging field with their high performance and substrate adaptability, while solvent-free laminating adhesives are gradually expanding the market with their green environmental protection and low operating costs. The choice of the two should be comprehensively evaluated based on the performance requirements, environmental protection requirements, cost budget and production equipment conditions of the packaging products. In the future, through technological innovation and process optimization, solvent-based and solvent-free flexible packaging adhesives will further complement each other and provide more abundant solutions for the flexible packaging industry.
