What is TPU andTPU UV INK?
TPU is a thermoplastic elastomeric material between rubber and plastic, full name is Thermoplastic Polyurethane.
TPU Core features:
The outstanding advantages of TPU can be summarized as "four high and one strong":
1.High elasticity: Extremely wide hardness range (Shore A 60 to Shore D 80), maintaining excellent rebound throughout.
2.High abrasion resistance: Abrasion resistance is than 5 times that of natural rubber, far exceeding PVC/PU.
3.High weather resistance: Resistant to oil, water, mold, aging, and remains flexible -40℃~120℃69;
4.High environmental protection: Halogen-free flame retardant, phthalate-free, recyclable, to mature environmental protection materials17;
5.Strong processability: Thermoplastic-Heat softening can be injection molded/extruded/blown, cooling sets the shape, no need for vulcanization
TPU UV ink is a high-adhesion, high-elasticity UV-cured ink specially designed for thermoplastic polyurethane (TPU soft substrates, with its core advantages being "no cracking, bendable, and UV resistant", widely used in printing scenarios such as mobile phone cases, sports shoes, and flexible.
TPU material has excellent elasticity, abrasion resistance and transparency, but its surface polarity is low, which can easily lead to poor adhesion of inks and cracking after bending. Therefore, special UV ink is required: strong adhesion, high flexibility and fast photopolymerization are achieved through formula optimization.
Classification and selection key dimensions
Different TPU UV inks are divided into two main categories according to the properties of the film layer after curing, choice depending on the final use requirements for flexibility vs hardness/abrasion resistance:
|
Dimension |
UV Soft (flexible) ink |
Hard (rigid) ink |
Key difference |
|
Membrane characteristics |
High elasticity, stretchable/bendable without cracking |
High hardness (≥6H), high gloss, scratch resistance |
Flexible ink for heavy deformation adaptability, hard ink for heavy surface protection |
|
Typical applications |
TPU phone cases, leather goods, soft film, roller shutter advertising |
Hard plastic shells, signs, glass/metal decorations |
The base material needs to be frequently bent is the primary judgment criterion |
|
Adaptable head |
Epson DX5/DX7/XP600/TX800 |
Ricoh Gen5/Gen6,Epson etc. High Precision Printing Head |
Flexible ink emphasizes more on rheological stability, while Hard ink focuses on color gamut and curing efficiency. |
Key Points of Technical Implementation:
To ensure the stable performance of TPU UV ink, it relies on three supporting links:
1.Add Synergy: Regularly re-blend the ultraviolet absorber and hindered amine light stabilizer to synergistically delay TPU photo-aging;
2.Process Adation: It is necessary to match the wavelength (commonly used 365nm/395nm) and energy density of LED/UV lamp, avoiding over-c leading to brittleness or under-curing resulting in insufficient adhesion;
3.Environmental Compliance: Mainstream products have passed RoHS, REACH, and MSD certifications, and some meet the requirements of food contact level (such as FDA-certified UV absorbers).
Conclusion：
When choosing TPU UV ink, is advisable to first clarify whether the base material needs to be frequently bent – for flexible scenarios, choose UV Soft ink (such as EPN series), and for rigid decoration scenarios, choose UV Hard ink (such as Grando GD series); also confirm the compatibility of the head and the parameters of the UV curing equipment.