HDI Trimer (Hexamethylene Diisocyanate Trimer) is one of the most widely used classes of aliphatic polyisocyanates for two-component polyurethane (2K PU) coating systems. Thanks to its outstanding UV resistance, weatherability, chemical resistance, and mechanical durability, HDI Trimer has become the industry standard curing agent for premium polyurethane coatings.

HDI Trimer polyisocyanates are extensively used in automotive OEM and refinish coatings, industrial finishes, protective coatings, marine coatings, rail coatings, aerospace coatings, plastic coatings, and composite applications where long-term durability, gloss retention, and color stability are critical.

Our product portfolio includes a comprehensive range of HDI Trimer polyisocyanates with different NCO content, viscosity, solids content, and solvent options, allowing formulators to optimize performance for virtually any polyurethane coating system.

^{Key Features and Benefits}

HDI Trimer polyisocyanates provide an excellent balance of processing performance and long-term coating durability.

Main advantages

• Excellent UV resistance
• Outstanding weather resistance
• Superior gloss retention
• Excellent color stability and non-yellowing performance
• High chemical resistance
• Excellent abrasion and scratch resistance
• High mechanical strength
• Suitable for High Solids coating formulations
• Supports Low VOC coating development
• Excellent compatibility with a wide range of hydroxyl-functional resins
• Consistent product quality for industrial manufacturing

^{Typical Applications}

HDI Trimer polyisocyanates are widely used in the production of:

• Industrial polyurethane coatings
• Protective and anti-corrosion coatings
• Automotive OEM coatings
• Automotive refinish coatings
• Heavy equipment finishes
• Agricultural machinery coatings
• Rail coatings
• Marine coatings
• Aerospace coatings
• Plastic coatings
• Composite coatings
• High-gloss clear coats
• Architectural metal coatings

^{Typical Technical Properties}

Typical characteristics of HDI Trimer polyisocyanates include:

Actual values depend on the specific product grade.

^{HDI Trimer Product Range}

Our HDI Trimer portfolio includes products optimized for different coating technologies and processing requirements.

Technical data shown above represents typical values and should be verified against the latest Technical Data Sheet (TDS).

^{Resin Compatibility}

HDI Trimer polyisocyanates are compatible with most hydroxyl-functional binders used in polyurethane coatings, including:

• Hydroxyl acrylic resins
• Polyester polyols
• Polyurethane polyols
• Acrylic polyol systems
• Polyaspartic resins
• Specialty hydroxyl-functional polymers

This broad compatibility allows formulators to develop coating systems with optimized curing speed, hardness, flexibility, weatherability, and chemical resistance.

^{Countertypes (Equivalent Products)}

Our HDI Trimer polyisocyanates are designed as functional alternatives to products from leading global manufacturers.

Disclaimer: Countertype information is provided for reference only. Final product selection should be based on laboratory evaluation, including NCO content, viscosity, solids content, solvent type, functionality, curing behavior, and formulation compatibility.

^{How to Select the Right HDI Trimer}

Selecting the appropriate HDI Trimer depends on several formulation parameters, including:

• NCO content
• Viscosity
• Non-volatile content
• Solvent system
• VOC requirements
• Pot life
• Cure speed
• Weather resistance
• Chemical resistance
• Gloss retention
• Resin compatibility
• End-use application

Our technical team can assist in selecting the most suitable product for new developments, formulation optimization, or replacement of existing imported materials.

^{Frequently Asked Questions (FAQ)}

^{What is an HDI Trimer?}

An HDI Trimer is an aliphatic polyisocyanate produced by trimerization of hexamethylene diisocyanate (HDI). It is primarily used as a curing agent for two-component polyurethane coatings, providing outstanding UV durability, weather resistance, chemical resistance, and mechanical performance.

^{What is the difference between HDI Trimer and HDI Biuret?}

Although both products are based on HDI chemistry, they differ in molecular structure and performance characteristics.

HDI Trimer generally provides higher solids content, better gloss retention, superior weatherability, and excellent long-term color stability, making it the preferred choice for premium industrial and automotive coatings.

HDI Biuret products typically offer lower viscosity, improved wetting, and are often selected for formulations requiring easier application or thicker film builds.

^{How do I choose an alternative to Desmodur® N3300?}

Selecting an equivalent product requires evaluation of several technical parameters, including:

• NCO content
• Viscosity
• Solids content
• Solvent system
• Functionality
• Reactivity
• Compatibility with the selected resin system

Our technical specialists can recommend the most suitable alternative based on your formulation and performance requirements.

^{Can imported HDI Trimer products be replaced without changing the formulation?}

In many applications, yes. Modern HDI Trimer polyisocyanates are designed to match the performance of leading international products. However, laboratory validation is always recommended before full-scale commercial production.

^{What industries use HDI Trimer polyisocyanates?}

HDI Trimer products are widely used in:

• Industrial coatings
• Protective coatings
• Automotive OEM coatings
• Automotive refinish coatings
• Marine coatings
• Rail coatings
• Aerospace coatings
• Plastic coatings
• Composite coatings
• High-performance clear coats

^{Why are HDI Trimer polyisocyanates preferred for exterior coatings?}

Because HDI Trimer is an aliphatic polyisocyanate, it provides exceptional resistance to ultraviolet radiation and weathering. Coatings formulated with HDI Trimer maintain gloss, color, and mechanical performance significantly longer than systems based on aromatic isocyanates, making them ideal for demanding outdoor applications.

^{Technical Support}

Beyond supplying high-quality polyisocyanates, we provide comprehensive formulation and technical support for polyurethane coating manufacturers.

Our specialists can assist with product selection, formulation optimization, replacement of imported curing agents, and development of new polyurethane systems.

Technical Data Sheets (TDS), Safety Data Sheets (SDS), Certificates of Analysis (COA), product samples, and formulation guidance are available upon request.