What is T-7138H Resin?
T-7138H is a di-functional aliphatic urethane acrylate resin designed specifically for adhesion to organic and inorganic materials including glass, ceramic, and oxidized metals. Its molecular architecture enables powerful chemical anchoring to challenging substrates without relying on traditional silane coupling agents, simplifying production processes and reducing system complexity.
The resin features a molecular weight of 3500 (GPC) and a glass transition temperature (Tg) of 52°C, offering an optimized balance between curing speed and mechanical performance. Its viscosity at 25°C is 16,000 mPa·s, combined with 35% elongation at break, delivering both high surface hardness and adequate toughness to prevent coating brittleness.
Technical Specifications
| Parameter | Typical Value |
|---|---|
| Resin Type | Di-functional Aliphatic Urethane Acrylate |
| Appearance | Clear Liquid |
| Color (Gardner) | ≤ 2 |
| Molecular Weight (GPC) | 3500 |
| Glass Transition Temperature (Tg) | 52°C |
| Elongation at Break | 35% |
| Viscosity at 25°C | 16,000 mPa·s |
| Acid Value | max. 3 mg KOH/g |
| Specific Gravity | 1.05 |
| Effective Content | 100% |
| Functional Group | 2 |
The resin has passed 1,000 hours of QUV accelerated aging tests with no significant chalking or discoloration, proving its long-term durability.
Core Performance Advantages
Unmatched Adhesion on Difficult Substrates
T-7138H delivers exceptional cross-cut adhesion (5B level) on float glass and tempered glass, as well as on ceramics, anodized aluminum, and galvanized steel. The key breakthrough lies in its ability to achieve this adhesion without relying on traditional coupling agents. The unique molecular design incorporates polar anchoring groups that form strong chemical bonds directly with inorganic substrate surfaces.
Outstanding High-Temperature Resistance
The resin withstands continuous service temperatures of 200-220°C, making it ideal for applications such as PCB wave soldering (instant high-temperature shock at up to 260°C) and high-temperature curing processes like bottle label firing. After 2 hours of continuous exposure at 220°C, the coating exhibits no yellowing or powdering, with adhesion retention exceeding 90%.
Exceptional Water Boil Resistance
T-7138H passes extended boiling water tests without depending on traditional coupling agents. After 48 hours of boiling water immersion, the coating maintains ASTM D3359 Grade 0 adhesion levels. This property is particularly critical for applications requiring sterilization, such as food cans, beverage containers, and kitchen appliance glass panels.
High Surface Hardness with Low Shrinkage
The cured film exhibits high surface hardness and strong scratch resistance while achieving extremely low shrinkage (<1%) during curing. This near-zero shrinkage minimizes internal stress-a critical factor for maintaining adhesion and preventing warping or delamination. After 1,000 steel wool abrasion cycles, the coating still retains over 90% of its original gloss and surface smoothness.
Fast Curing & 100% Reactive Content
As a 100% solids, solvent-free resin, T-7138H contains no volatile monomers (VOC-free), emits no irritating odor, and complies with stringent environmental regulations. Its UV curing time is controllable within 3-5 seconds (365 nm light source, light intensity ≥80 mW/cm²), supporting high-speed automated production lines.
Application Areas
UV-Curable Adhesives
High-Temperature Structural Bonding: T-7138H is used for permanent, high-strength bonding of glass-to-glass or glass-to-metal applications, offering ideal bond strength and water resistance. It contains no monomers, has no irritating odor, cures fast, and exhibits low shrinkage.
Electronic Assembly: Suitable for temporary fixing or potting of components that must endure subsequent high-temperature processing steps. When used as a PCB temporary protective coating, it withstands wave soldering and can be easily removed with no residue left behind.
UV-Curable Coatings
Vacuum Metallization Primer: Serves as the main resin in UV primers for glass packaging products (cosmetic bottles, wine bottles, etc.) prior to vacuum plating. It provides unparalleled adhesion and prevents the plated layer from developing iridescence (rainbow effects) or hazing.
High-Performance Industrial Coatings: Used in coatings for BMC automotive lamps and other surfaces requiring extreme heat and weather resistance. The resin's high-temperature durability ensures no yellowing and no delamination during curing. It also performs well in outdoor applications such as architectural glass curtain walls and exterior metal components.
UV-Curable Inks
Specialty Screen Printing Inks: For decorative or functional screen printing on inorganic materials like glass, ceramic, and metal, providing excellent adhesion. In wine bottle heat-transfer printing, the pattern remains clear with no yellowing after 220°C baking, and water boil resistance meets long-term storage requirements for the beverage industry.
Metal Decorating Inks (Tinplate): For roller-coating or offset printing on food cans and beverage cans. Formulations containing T-7138H pass high-temperature retort and sterilization tests, making them suitable for premium packaging requiring both safety and durability.
Formulation Recommendations
To maximize the performance of T-7138H in specific applications, careful monomer selection is essential.
For Vacuum Metallization Coatings & Inks (Glass/Metal Substrates)
Recommended Monomer: AM-324
When used together, T-7138H and AM-324 achieve reduced shrinkage, increased curing speed, and help prevent the plated layer from developing iridescence or hazing-common defects that compromise the metallic finish and adhesion quality.
For UV Adhesives (Bonding Applications)
Recommended Monomer: AM-319 (4-tert-Butylcyclohexyl acrylate)
This combination counteracts the shrinkage effects of high-functionality monomers and ensures ultimate adhesion to glass and metal substrates. AM-319 helps balance volumetric shrinkage, reducing internal stress for more durable bonds.
Polymer Compatibility
T-7138H demonstrates excellent compatibility with polyester, epoxy, urethane, phosphate ester, and acrylate resins. This broad compatibility provides formulation flexibility for developing differentiated products tailored to specific application requirements.
Photoinitiator and Co-initiator Recommendations
T-7138H can be formulated with a variety of photoinitiators depending on curing wavelengths (UVA or LED). General recommendations include 2–4% photoinitiator and 2–5% co-initiator based on total resin weight, adjusting for specific curing equipment and film thickness.
Processing & Curing Guidelines
For optimal performance with T-7138H, the following processing parameters are recommended:
| Parameter | Recommended Value |
|---|---|
| Curing Energy | 800–1,200 mJ/cm² |
| Lamp Type | Medium-pressure mercury lamp (80–120 W/cm) |
| Wavelength | 365 nm or 385 nm |
| Curing Speed (Coating) | <5 seconds (≤ 5 m/min) |
| UV Intensity | ≥80 mW/cm² |
| Light Source | UV/LED 365 nm or 385 nm |
Substrate Preparation
Metal surfaces: Degrease and passivate before coating. For anodized aluminum substrates, pairing with a phosphate ester adhesion promoter is recommended.
Glass surfaces: Clean and dry thoroughly; no chemical primer required due to the resin's excellent intrinsic adhesion.
Storage Conditions
Store in sealed containers, protected from light, in a cool, dry environment below 25°C.
Once opened, the resin should be used within 6 months to prevent viscosity changes.
Packaging Options: 20 kg plastic drum or 200 kg iron drum.
Why Choose T-7138H?
T-7138H is more than just a resin; it is a comprehensive solution for engineers and formulators seeking to push the boundaries of their UV-curable products. It simplifies manufacturing, enhances durability, and ensures consistent results on the most challenging substrates.
Eliminates dependency on coupling agents - simplifies formulations and reduces costs
Delivers reliable performance from -40°C to 220°C - withstands thermal cycling with no degradation
Boiling water resistant - passes 48-hour water immersion and retort sterilization
Near-zero shrinkage - prevents coating cracking and delamination
Fast UV/LED curing - supports high-speed production while maintaining 5B adhesion
100% solids, VOC-free - meets global environmental regulations
As industrial manufacturing continues to demand higher precision and greater reliability, T-7138H provides the advanced material performance needed to meet these challenges effectively.
Frequently Asked Questions
Q: Can T-7138H replace silane coupling agents entirely?
A: Yes, this is one of the key breakthroughs of T-7138H. Its molecular design incorporates potent polar anchoring groups that allow it to bond directly to inorganic surfaces without needing additional coupling agents.
Q: What is the maximum temperature T-7138H can withstand?
A: The resin withstands continuous service temperatures of 200–220°C and can endure wave soldering peak temperatures exceeding 260°C for short periods.
Q: Is T-7138H suitable for outdoor applications?
A: Yes. Accelerated aging tests (1,000 hours QUV) show no significant chalking or discoloration, making it suitable for long-term outdoor exposure.
Q: Can T-7138H be cured with LED light sources?
A: Yes. The resin cures effectively under both traditional UV lamps and LED light sources at 365 nm or 385 nm wavelengths.
Q: Is T-7138H compliant with environmental regulations?
A: Yes. As a 100% solids resin with zero VOC content and no irritating monomers, it meets stringent environmental standards and supports sustainable manufacturing practices.
Q: How should T-7138H be stored for maximum shelf life?
A: Store in sealed containers below 25°C, protected from light. Once opened, use within 6 months.