Multi-layer Co-extrusion Packaging Adhesive Resins: A Comprehensive Analysis of Industry Status, Technological Trends, and Domestic Substitution

Multi-layer Co-extrusion Adhesive Resins: Industry Status, Technology Trends, and a Complete Analysis of Domestic Substitution

Prepared-food retort pouches, high-barrier fresh-keeping films, EVOH multi-layer juice bottles, pharmaceutical oxygen-barrier rigid sheets, under-floor heating oxygen-barrier pipes … Today, virtually all high-performance composite products in food, pharmaceutical, daily chemical, and industrial packaging rely on multi-layer co-extrusion to achieve functional upgrades. The invisible core material that ensures stable bonding between different substrates and prevents delamination and leakage is precisely the multi-layer co-extrusion adhesive resin.

In packaging material systems, polyolefins such as PE and PP are non-polar materials with excellent heat resistance, toughness, and processability; EVOH, nylon PA, PET, aluminium foil, etc. are polar materials that offer ultra-high barrier properties, high-temperature resistance, oxygen and moisture barrier performance. However, the molecular structures of these two classes of materials are fundamentally different, and their interfacial compatibility is extremely poor. Direct melt co-extrusion easily leads to interlayer delamination, separation after retort, heat-seal leakage, low-temperature cracking, and other fatal quality issues.

The advent of adhesive resins perfectly solves this industry pain point. Through grafting modification technologies such as maleic anhydride (MAH) and acrylate grafting, adhesive resins can simultaneously compatibilise non-polar polyolefins and polar functional substrates. By combining physical chain entanglement with chemical bonding, they act as a dedicated plastic bridge in multi-layer composite structures. As solvent-free functional materials that can be co-extruded simultaneously, they produce no VOC emissions and require no secondary lamination, fully aligning with the industry policies of green packaging and low-carbon production.

For a long time, the global high-end adhesive resin market has been dominated by oligopolistic brands such as DuPont & Dow’s BYNEL™ and Mitsui Chemicals’ ADMER™. Domestic mid-to-high-end packaging companies have long faced challenges including long import lead times, frequent price fluctuations, lack of customised grades, and supply chain instability. In recent years, with rapid breakthroughs in domestic polymer modification technologies, continuous capacity expansion in downstream multi-layer co-extrusion packaging, and policy guidance towards self-reliant supply chains, the adhesive resin industry has formally entered a golden period of accelerating domestic substitution.

This article dissects the multi-layer co-extrusion adhesive resin industry from six dimensions — product principles, benchmark product systems, downstream applications, industry landscape, technology trends, and the pain points and pathways for domestic substitution — to provide a professional reference for packaging practitioners, raw material purchasers, and R&D personnel in new materials.

1. Core Principles, Classification, and Benchmark Product Systems of Adhesive Resins

1.1 Core Mechanism of Action

Currently, the mainstream adhesive resins in the industry are produced by melt-grafting modification, using common polyolefins such as LLDPE, HDPE, PP, and EVA as the backbone, onto which polar functional groups such as maleic anhydride (MAH) and acrylate are grafted through precisely controlled processes. The bonding mechanism relies on a dual action: on one hand, the resin backbone undergoes melt entanglement with PE and PP molecular chains, achieving firm physical bonding; on the other hand, the polar side groups can react in situ with the amino groups of nylon, the hydroxyl groups of EVOH, and the ester groups of PET, forming irreversible chemical adhesive structures.

Compared with traditional liquid adhesives, adhesive resins can be co-extruded, blown, or cast simultaneously with multi-layer substrates, simplifying the process, leaving no solvent residues, and generating no secondary pollution. They are thus an essential core material for the mass production of modern high-barrier composite packaging.

1.2 Benchmark Imported Product Systems

The global high-end adhesive resin market is oligopolistic. DuPont & Dow’s BYNEL™ and Mitsui Chemicals’ ADMER™ have comprehensive product portfolios, stable performance, and mature regulatory compliance systems, and they have long been the traditional first choice for high-end packaging companies worldwide.

DuPont & Dow BYNEL™ Key Series

PE-based MAH-modified series (41E/4100 series): The industry’s general-purpose high-end adhesive resin and the most widely used benchmark system. Suitable for bonding PE with EVOH and nylon PA in multi-layer co-extruded structures, offering excellent retort resistance and stability. Widely used in 121 °C retort pouches, high-barrier co-extruded films, and multi-layer barrier blow-moulded containers in mid-to-high-end food packaging, directly competing with Mitsui’s ADMER NF series.

PP-based MAH-modified series (50E/5000 series): A dedicated adhesive system for polyolefin-based structures, specifically addressing the difficulty of bonding PP with EVOH and PA polar materials. Mainly used in PP-based multi-layer barrier films, rigid polypropylene packaging, and thermoformed food trays.

Acrylate-modified series (22E series): A differentiated functional system with excellent adhesion to PET, paper, aluminium foil, etc., making it a core special adhesive for paper/plastic lamination, aluminium/plastic laminates, and extrusion coating processes.

EVA-modified series (3100 series): Soft materials with excellent low-temperature processability, suitable for low-temperature forming processes and commonly used in light-duty flexible packaging and general composite films for low-load, non-high-temperature applications.

Mitsui Chemicals ADMER™ Key Series

NF series (PE-based): Mitsui’s core high-end workhorse series, offering excellent comprehensive retort resistance, peel strength, and batch-to-batch stability. Suitable for PE/EVOH/PA multi-layer co-extruded structures, widely used in high-end food retort films and high-barrier blow-moulded containers. It is the main imported grade directly competing with Dow’s 41E series.

QF series (PP-based): A dedicated adhesive system developed for polypropylene substrates, suited for PP/PA and PP/EVOH composites, mainly used in rigid and industrial applications such as multi-layer barrier pipes and industrial composite components.

SF series (specialty reinforced type): A high-bond-strength, solvent-resistant differentiated product, focused on high-end industrial composites and speciality barrier packaging where adhesion stability and media resistance are extremely demanding.

1.3 Core Downstream Application Scenarios

Flexible food packaging (core growth market): Includes prepared-food retort pouches, frozen fresh-food high-barrier films, dairy lidding films, meat vacuum bags, and liquid bag-in-box. Key requirements are no delamination after 121 °C retort, stable peel strength, and compliance with GB 4806 food-contact safety standards.

Rigid co-extruded packaging: EVOH multi-layer juice bottles, sauce barrier blow-moulded containers, PP/PA thermoformed trays, and pharmaceutical sterile oxygen-barrier rigid sheets, which impose strict demands on melt strength, thermal stability, and low oligomer extractables.

Paper/plastic and aluminium/plastic laminates: Food paper cups, aseptic packaging substrates, kraft paper/aluminium/plastic composite films, suitable for extrusion coating and lamination processes with polar substrates such as PET, aluminium foil, and paper.

Industrial applications: Under-floor heating EVOH oxygen-barrier pipes, chemical-resistant multi-layer barrier drums, aluminium-composite panel adhesive layers, etc., relying on stable interfacial adhesion to ensure long service life in industrial products.

2. Global and Domestic Market Landscape and Supply Status

2.1 Global Market: Foreign Oligopolies Dominate the High-End Segment

The global high-barrier adhesive resin industry is highly concentrated. DuPont & Dow and Mitsui Chemicals, with decades of accumulated expertise in molecular modification, precision process control, and complete global regulatory certification systems, together hold over 80 % of the global high-end market share. Other foreign players such as ExxonMobil and BASF cover only mid-to-low-end applications like general-purpose composite films and ordinary industrial pipes.

The core technological barrier of the industry is not the basic grafting modification formulation, but rather the capability for sophisticated production control. Leading foreign companies possess mature continuous production systems and long-term process know-how, resulting in stable grafting ratios, extremely low residual oligomers, excellent resistance to hydrolytic and thermal ageing, and strong batch-to-batch consistency, making them perfectly suited for demanding applications such as food retort and pharmaceutical aseptic packaging. Early domestic production processes were relatively rudimentary, with limited process controllability, often leading to delamination, gel contamination, and retort-failure quality issues in mass production.

2.2 Domestic Market: High Growth, Low Self-Sufficiency, Accelerating Localisation

With the explosive growth of China’s prepared-food, pharmaceutical packaging, and high-end daily chemical sectors, the domestic adhesive resin market has maintained rapid growth, significantly outpacing the average growth rate of general plastics. The localisation of raw materials is steadily accelerating.

Current domestic demand shows three core characteristics: first, the continuous expansion of the prepared-food sector drives a sharp increase in demand for retort-grade adhesive resins, which is currently the most critical rigid demand for high-end imported adhesive resins; second, the rising threshold for pharmaceutical aseptic packaging imposes stringent requirements for low extractables and high cleanliness in high-end adhesive resins, a field still dominated by foreign brands; third, as the packaging industry gradually shifts to central and western China, the advantages of local raw materials — flexible delivery, rapid response, and close technical service — become increasingly prominent.

2.3 Overall Development Status of Domestic Enterprises

With the continuous iteration of domestic polymer modification technologies, the domestic adhesive resin industry has become generally mature, though it exhibits a stratified development pattern. After years of technical accumulation and process refinement, China now has the capability to produce maleic anhydride-grafted polyolefin adhesive resins on an industrial scale, stably matching the requirements of most conventional packaging and industrial composite applications, and has essentially achieved import substitution for general-purpose grades.

Overall, most domestic adhesive resin manufacturers focus on general-purpose products and the mid-range conventional market. Their products can satisfy basic applications such as ordinary frozen films, non-retort lamination, and general pipes. However, in high-end dimensions such as ultra-high hydrolytic/thermal resistance, ultra-low extractables, long-term stability, and specialised grades, a clear gap remains compared with mature imported products. High-end retort, pharmaceutical aseptic, and export-oriented high-requirement applications still heavily rely on imported materials.

In the overall push towards high-end development, a number of growing enterprises have emerged, leveraging core modification technologies and cross-sector expertise in the adhesive resin field. Represented by Shanghai Jiuju Polymer Co., Ltd., such companies have been deeply engaged in the R&D and production of polymer compatibilisers and tougheners for over twenty years, with a long-term focus on polyolefin grafting modification, interfacial compatibilisation, and toughening technologies. They have accumulated deep technical expertise and R&D experience in molecular design, grafting process control, and interfacial performance optimisation. Based on their homologous grafting modification technology, they have strategically expanded into the multi-layer co-extruded functional materials sector, independently developing a series of adhesive resin products suitable for polar substrates such as EVOH, PA, and aluminium foil, targeting mid-to-high-end applications including high-barrier films, food and cosmetic tubes, and composite pipes. Leveraging their mature modification technology platform, these companies continuously optimise processes, strictly control batch consistency, and address the shortcomings of domestic materials in terms of low extractables, hydrothermal resistance, and low gel content. Their products increasingly benchmark the performance of major imported grades, and with solid technical foundations, localised service, and cost-effectiveness, they are steadily entering mid-to-high-end packaging supply chains, emerging as a new force in the domestic substitution of adhesive resins.

3. Core Technology Trends in the Industry

3.1 Controlled Grafting and Low-Extractables Processes Become the High-End Standard

Traditional melt-grafting processes are prone to residual peroxides and low-molecular-weight oligomers, posing food-safety risks in high-temperature retort applications. Therefore, low-residue, high-stability controlled grafting technologies have become a core R&D direction. By optimising low-dosage initiator formulations, narrow molecular-weight distribution control, and multi-stage vacuum devolatilisation refining, the migration of low-molecular-weight species can be significantly reduced, meeting the stringent compliance requirements of food and pharmaceutical applications. Leading domestic manufacturers have now fully adopted this process route to upgrade high-end product performance.

3.2 Lightweighting and Thinning for High-Speed Co-Extrusion Equipment

Downstream packaging equipment is continuously upgrading towards higher speeds and thinner films. The adhesive layer thickness has been reduced from the traditional 15 μm to 5–8 μm, placing higher demands on melt strength and rheological compatibility. The mainstream R&D direction is molecular branching design, which ensures excellent adhesion while balancing flowability and melt strength, making it compatible with high-speed multi-layer co-extrusion dies, reducing material consumption, and supporting packaging lightweighting and cost reduction.

3.3 Recyclable and Bio-Based Materials Emerge as New Fronts

With the tightening of global plastic recycling and restriction policies, the difficulty of recycling mixed-material multi-layer films has become a prominent industry pain point. Major companies are focusing on developing recyclable compatibilising adhesive resins that allow co-recycling of multi-layer materials without delamination. At the same time, bio-based adhesive resins are entering pilot-scale stages, suitable for biodegradable composite packaging, and represent a long-term growth opportunity.

3.4 Product Specialisation and Customisation Replace General-Purpose Approaches

In the past, a single general-purpose grade could cover most scenarios. Today, downstream requirements are becoming increasingly segmented, with demand surging for specialised grades such as ultra-high-temperature sterilisation grades, pharmaceutical low-extractables aseptic grades, paper/lamination special grades, and hydrolysis-resistant long-life grades for pipes. The industry has formally moved away from the “one-size-fits-all” coarse model, and fine-tuned specialty grades have become a core competitive advantage.

4. Domestic Substitution: Core Gaps, Development Opportunities, and Implementation Pathways

4.1 Core Gaps Between Domestic and Imported Products

Current domestic adhesive resins have achieved comprehensive substitution in the mid-range market, but in high-end applications they still face four major shortcomings compared with DuPont & Dow BYNEL and Mitsui ADMER:

Insufficient process control precision: Foreign manufacturers operate mature continuous production lines with precise process control, extremely low grafting-ratio variability, and excellent stability. Most domestic production lines still lag in process control accuracy, with relatively higher dispersion in grafting ratios and occasional minor performance fluctuations during mass production.

Inadequate long-term hydrothermal stability: Imported high-end products exhibit very low degradation in adhesion after retort and long-term hydrothermal ageing. Most domestic general-purpose materials still have room for improvement in long-term hydrothermal and ageing resistance, limiting their suitability for high-requirement export-oriented prepared-food packaging.

Incomplete global regulatory certifications: Imported brands possess comprehensive food-contact certifications from the FDA, EU, Japan, and other regions. Most domestic manufacturers only hold GB 4806 certification within China, with limited adaptability to overseas markets.

Narrow grade portfolios and weaker technical service: Foreign companies offer hundreds of specialised grades and tailored process solutions, whereas domestic companies have leaner grade matrices and are still developing their customised technical service capabilities.

4.2 Three Core Opportunities for Domestic Substitution

Policy opportunity: High-performance polyolefin adhesive resins have been included in national key-new-material support catalogues, and policies promoting self-reliant supply chains are driving downstream companies to proactively establish dual-source material systems, mitigating risks of import disruptions and price spikes.

Cost and delivery opportunity: Equivalent-performance domestic high-end materials are priced 15 %–25 % lower than imported alternatives, and they do not require long ocean shipping lead times. They offer spot availability, rapid sample delivery, and short-term customisation, perfectly matching the fast-iteration production needs of domestic packaging companies.

Industry-scenario opportunity: China’s huge multi-layer co-extrusion packaging industry and its rich application scenarios provide abundant mass-production demand, which serves as an excellent testing ground for continuous iteration and validation, helping late-comer domestic manufacturers rapidly improve product performance and narrow the gap with imports.

4.3 Phased Implementation Pathway for Domestic Substitution

Phase 1: Full substitution in the mid-range market (already achieved): In conventional applications such as ordinary frozen films, non-retort lamination, and industrial pipes, domestic MAH-grafted adhesive resins have completely replaced imported products and now hold a dominant market share.

Phase 2: Batch introduction into the mid-to-high-end retort market (currently underway): Represented by home-grown enterprises, domestic producers continue to benchmark imported retort-grade products such as NF528 and BYNEL 41E. After multiple rounds of process iteration and end-user validation, overall product performance has improved significantly. Batch blending substitution has already been achieved in prepared-food and daily-chemical high-barrier packaging, steadily breaking into the mid-to-high-end market.

Phase 3: Full breakthrough in high-end pharmaceutical and export markets (next 3–5 years): Addressing the three core bottlenecks of low extractables, long-term hydrothermal resistance, and global regulatory certifications, to achieve complete domestic substitution in high-end sterile pharmaceutical packaging and export food packaging.

5. Current Challenges and Future Outlook

5.1 Core Challenges Facing the Industry

Severe homogenisation and price wars in the low-end market: Numerous small plants with no R&D or quality control rely on low prices to capture market share, damaging the overall reputation of domestic materials.

Dependence on imported high-end additives and high-purity monomers: Some key auxiliary agents and high-purity monomers still rely on imports, limiting further performance upgrades.

Low fault tolerance among downstream packaging companies: Switching adhesive resins typically requires 3–6 months of long-term validation, making the localisation transition relatively slow.

5.2 Long-Term Industry Outlook

In the future, the domestic adhesive resin market will continue to expand. Upgrading in prepared-food, biopharmaceuticals, and high-end daily chemicals will steadily increase the penetration rate of multi-layer co-extruded structures. At the same time, industry concentration will rise, with smaller manufacturers lacking R&D and quality control gradually being phased out, and resources concentrating on leading players with integrated R&D, production, testing, and service capabilities.

Overall, domestic adhesive resins are transitioning from “low-cost alternatives” to “high-quality substitutes and customised surpasses.” In the future, domestic companies will leverage specialised grades, environmentally recyclable products, and localised customisation and technical services to completely break the long-standing duopoly of overseas players. This will not only make the domestic supply chain self-reliant but also position Chinese products to compete globally with high cost-performance ratios.

Conclusion

Multi-layer co-extrusion adhesive resins, as the invisible backbone of high-barrier packaging, represent a typical arena for domestic substitution of functional polymer materials. For decades, foreign brands have monopolised the high-end market through technological and certification barriers. However, with breakthroughs in domestic precision modification processes, improvements in the local industrial chain, and the persistent R&D efforts of leading companies, the performance stability, regulatory compliance, and practicality of domestic products have achieved remarkable leaps.

For downstream packaging companies, building a dual-source localisation supply chain is a core measure to hedge against import risks and reduce costs while improving efficiency. For new-material enterprises, deepening specialised technologies, improving compliance systems, and offering customised services are key to seizing the industry dividend. It is foreseeable that the full domestic substitution of multi-layer co-extrusion adhesive resins will be an irreversible core trend in the packaging new-materials industry over the coming years.