Against the backdrop of increasingly strict global environmental regulations, water-based coatings and adhesives are gradually replacing solvent based systems and are widely used in core fields such as industrial packaging, printing, and composite film coating. Although water-based systems have significant advantages in environmental protection and safety, there are still many pain points in practical applications, such as insufficient water and heat resistance, uneven adhesion on complex substrate surfaces, and weak mechanical properties due to low cross-linking density, which have become key bottlenecks restricting their high-end applications.
To solve the above problems, functional crosslinking agents have become the core solution for improving the performance of water-based systems. Among numerous innovative technologies,Langyi New Materials HyMax ® CA polycarbodiimide environmentally friendly water-based crosslinking agentBy virtue of its non-toxic and environmentally friendly nature, high reactivity, and excellent compatibility with multiple polymer systems, it stands out and can achieve efficient and durable crosslinking modification in aqueous systems without the need for toxic isocyanates, balancing performance and safety.
01.
Reaction mechanism of polycarbodiimide (PCDI)
Polycarbadiamide (PCDI) is a polymer whose main chain is rich in multiple functional groups of carbodiimide (- N=C=N -). The active group can react with the carboxyl group (- COOH) widely existing in water-borne resins (polyurethane dispersion, acrylic lotion, alkyd resin, PVA copolymer, etc.) with high efficiency.
Main cross-linking reactions:
Reaction type: Nucleophilic addition reaction
Generating Bond: Stable Urea Bond (- NH-CO-N -)
Reaction conditions: No catalyst required, can be quickly carried out at room temperature or heating
Reaction advantages: zero by-products, no gas release, no VOC emissions, belonging to green and clean cross-linking reaction
This reaction can construct a dense three-dimensional polymer network, significantly improving the integrity, chemical corrosion resistance, and thermal stability of the coating.
Other reaction pathways:
Hydrolytic crosslinking: Under humid conditions, the carbodiimide group can slowly react with water to form urea derivatives, which can achieve long-term auxiliary crosslinking and improve system stability.
Multi point crosslinking: The polymer structure endows PCDI with multiple active sites, which can simultaneously connect multiple molecular chains, greatly enhancing the cohesion and toughness of the material.
specialsex | advantage |
Non toxic, without cyanide | Production, storage, and application are all safe and environmentally friendly throughout the process |
Low mobility | Permanently bonded to the polymer matrix without precipitation or migration |
Wide compatibility of formulas | Suitable for polymerization agents, acrylic acid PVA、 Alkyl and mixed emulsion |
Excellent thermal and hydrolytic stability | Especially suitable for application scenarios with strict requirements for heat resistance, moisture and heat aging resistance |
High reactivity and good storage stability | Long shelf life under dry conditions; Slow sensitivity to moisture |
low viscosity | Suitable for various water-based formulas, easy to process and mix |
1. Strengthen water and chemical resistance
PCDI cross-linking can form a dense coating, effectively inhibiting expansion, water permeability, and chemical erosion, perfectly adapting to:
Industrial packaging protective coating
Cardboard barrier coating
Plastic and metal substrate protective film
2.Enhance adhesion and mechanical strength
Enhance adhesive cohesion and substrate adhesion, significantly improve peel strength, heat resistance, and long-term bonding stability, suitable for:
Membrane to membrane composite process
Plastic metal composite materials
Pressure sensitive adhesive (PSA) system
3. Excellent thermal durability
PCDI cross-linked coating can withstand high temperature processes such as heat sealing and baking curing, solving the problem of high-temperature failure of traditional water-based adhesives and maintaining the integrity of the system structure.
4. Optimize ink and varnish performance
Applied to water-based inks and glossy varnishes, it can significantly improve:
Scratch and wear resistance performance
Gloss retention and matte uniformity
Solvent resistance and aging resistance performance
Suitable for scenarios that require both aesthetics and durability, such as electronic packaging, high-end labels, and precision printing.
application field | Usage scenarios |
Industrial coating | Protective coatings on metals, plastics, or materials that meet the requirements |
Laminated adhesive | Water based adhesive for PET/PE, OPP/AL/PE film layers |
PSA label | High performance label adhesive with moisture resistance |
Transparent topcoat | Glossy or matte printed varnish for packaging or electronic products |
Functional paper coating | Waterproof/oil resistant coating for cardboard or cardboard packaging |
Langyi New Materials HyMax ® CA polycarbodiimide (PCDI) water-based crosslinking agentEffectively addressing the performance shortcomings of water-based systems while adhering to the bottom line of environmental protection and safety. It can form strong, non-toxic, and permanently cross-linked characteristics under mild conditions, making it an ideal additive for upgrading environmentally friendly formulas.
From coatings and adhesives to printing inks and composite film materials, PCDI comprehensively enhances the durability, stability, and functionality of materials, helping various industries accelerate their transformation towards high-performance and green water-based technologies. It is the core preferred choice for high-end water-based formulas.
