Key Characteristics
T-7333 is a solvent-free, single-component UV resin suitable for 100% solids formulations. Its main features include:
High initial tack – Fast wetting and bonding to various substrates, ideal for applications requiring immediate positioning.
Moderate cure speed – Fully curable under conventional UV lamps with minimal surface tack or undercure risk.
Non-yellowing – Good light and heat aging resistance, suitable for transparent or light-colored products.
Low volume shrinkage – Minimal dimensional change upon curing; prevents warping or curling when applied to thin films or coatings.
Hydrolysis and heat resistance – Retains performance under humid and high-temperature conditions, extending outdoor or harsh-environment service life.
Clear, colorless film – High light transmittance, does not alter the appearance of the substrate.
Applications in UV Pressure-Sensitive Adhesives
As a primary resin for UV PSAs, T-7333 balances initial tack and cohesive strength. This allows tapes or labels to wet out the substrate quickly during application while leaving minimal residue upon removal.
For applications such as self-adhesive printing, medical and sanitary tapes, industrial adhesives, and electronic components, T-7333 effectively bonds to metals, glass, metal oxide coatings, and even low-surface-energy plastic films (e.g., PE, PP). Importantly, its tack retention after multiple bonding/debonding cycles is excellent, making it suitable for removable or reusable PSA applications.
The low shrinkage characteristic prevents film substrates from curling after coating and curing, improving die-cutting and subsequent processing yields.
Applications in UV Coatings
In UV coating formulations, T-7333 is often used as an adhesion-promoting resin. It enhances adhesion to plastic substrates (such as PC, ABS, and treated PP) and improves the water resistance of the coating.
In vacuum metallization processes, T-7333 can be used in primer or topcoat layers to strengthen interlayer adhesion between the metal coating and the substrate. When blended with higher-hardness resins, it improves the hydrolytic stability of the overall coating without sacrificing too much flexibility.
For applications requiring a transparent protective layer, its colorless film does not alter the substrate's color or gloss.
Applications in UV Inks
In UV printing inks, T-7333 contributes in three main ways:
Enhanced adhesion – Improves ink anchorage on difficult substrates such as BOPP and PET films.
Reduced volume shrinkage – Lowers internal stress in the cured ink layer, minimizing film distortion and misregistration in multicolor printing.
Improved flexibility and hydrolysis resistance – Prevents the ink film from cracking or chalking under bending or humid conditions.
These characteristics make T-7333 suitable for flexible packaging printing, label printing, and industrial inks that demand weather resistance.
Formulation and Processing Considerations
Cure speed – T-7333 has a moderate cure speed. For high-speed coating lines (>50 m/min), it is recommended to use highly efficient photoinitiators (e.g., TPO, 819) and ensure sufficient UV dose (typically >300 mJ/cm²).
Adhesion to untreated PP – While T-7333 offers good adhesion to low-polarity plastics, it is advisable to perform corona or primer pretreatment on completely untreated PP for reliable bond strength.
Compatibility – When blending with highly polar monomers or resins, a compatibility test should be conducted first to avoid haze or phase separation.
Typical Formulation Examples (Starting Points)
UV PSA for Removable Protective Film
| Component | Parts by weight |
|---|---|
| T-7333 | 80–90 |
| Tackifier (e.g., terpene phenolic resin) | 10–20 |
| Photoinitiator (TPO) | 1–2 |
| Antioxidant (optional) | 0.5 |
*Cure condition: 300–500 mJ/cm², film thickness 20–50 µm.*
UV Coating for Plastic Adhesion Promotion
| Component | Parts by weight |
|---|---|
| T-7333 | 20–30 |
| Urethane acrylate (flexible) | 30–40 |
| Epoxy acrylate (hardness) | 20–30 |
| Photoinitiator (819/184 blend) | 3–4 |
| Solvent (if needed for spray) | Adjust |
*Cure condition: 400–600 mJ/cm², dry film thickness 10–20 µm.*
Summary
T-7333 polyurethane acrylate does not chase a single extreme property. Instead, it offers a well-balanced profile across initial tack, volume shrinkage, substrate versatility, and environmental resistance. For UV-curable PSAs, coatings, and inks requiring low deformation, repositionable adhesion, hydrolysis stability, and optical clarity, T-7333 represents a reliable technical option.
During formulation development, users are encouraged to adjust photoinitiator type and loading, blend ratios with other resins, and validate performance on target substrates through small-scale trials.