Hydroxyl acrylic resin for automotive coatings needs to provide more than gloss. It also needs good leveling, high film fullness, strong hardness, and reliable resistance performance. KN3378H is a high-solid hydroxyl acrylic resin developed for clear coats used on electric vehicles, motorcycles, helmets, and automotive refinishing applications.
KN3378H combines high gloss with excellent leveling and strong thick-film performance. In addition, it offers high hardness and good wear resistance, making it suitable for demanding two-component PU clear coat systems.
High Gloss and Excellent Leveling
Appearance is a key requirement for vehicle clear coats.
KN3378H provides high gloss and good leveling performance. In the reference test system, the 60° gloss reached 95, while the film showed a smooth surface without shrinkage defects.
At the same time, the coating showed good fullness and high distinctness of image. Therefore, formulators can use KN3378H when developing clear coats that require a deep, smooth, and premium finish.
High Solid Content for Full Film Build
KN3378H has a solid content of 75 ± 2%.
This high-solid characteristic supports strong film build and good fullness. Moreover, the product is designed for thick-film application and shows good resistance to solvent popping under the stated test conditions.
Typical properties include:
| Property | Specification |
|---|---|
| Composition | Acrylic copolymer |
| Appearance | Clear and transparent |
| Viscosity at 25°C | 6.0–12.0 Pa·s |
| Acid Value | 6–10 mg KOH/g |
| Solvent | Xylene / PMA |
| Color | ≤1 Fe-Co |
| Solid Content | 75 ± 2% |
| Hydroxyl Value | 138 |
These values give formulators a useful technical reference when designing two-component PU clear coat systems.
High Hardness and Wear Resistance
KN3378H is also designed for applications that require strong film durability.
The reference test results show a final pencil hardness of H. In addition, the coating showed good wear resistance, which is important for surfaces that face regular handling and contact.
Its flexibility result reached 1 mm, while cross-cut adhesion reached 100% under the documented test conditions.
As a result, KN3378H combines surface hardness with useful film flexibility.
Suitable for Automotive and Motorcycle Clear Coats
KN3378H is recommended for several vehicle coating applications:
- Electric vehicle clear coats
- Motorcycle clear coats
- Helmet clear coats
- Automotive refinish coatings
These applications often require a balance of appearance, hardness, fullness, and resistance performance.
Therefore, KN3378H provides a practical resin option for manufacturers developing premium 2K PU clear coat systems.
Reference 2K PU Clear Coat System
The technical document provides a reference two-component clear coat formulation using KN3378H as the main resin and N3390 as the curing component.
The reference mixing ratio is:
Part A : Part B : Thinner = 100 : 34.7 : 80–100
The documented baking condition is 70°C for 60 minutes, followed by a 24-hour holding period before resistance testing.
Because actual formulations may use different pigments, additives, film thicknesses, and curing conditions, manufacturers should confirm final performance in their own system before mass production.
Reference Performance
Under the stated test conditions, KN3378H achieved the following results:
| Test Item | Result |
|---|---|
| Surface Dry | 40 min |
| Hard Dry | 24 h |
| 24 h Pencil Hardness | H |
| 60° Gloss | 95 |
| Cross-Cut Adhesion | 100% |
| Flexibility | 1 mm |
| Fullness | Good |
| Leveling | Smooth, no shrinkage |
| Acid Resistance | Passed |
| Alkali Resistance | Passed |
| QUV Aging | 800 h, no discoloration or peeling, gloss loss ≤1% |
These results reflect the reference formulation and test conditions. Therefore, users should conduct their own formulation tests before commercial use.
Packaging and Storage
KN3378H is supplied in 200 kg drums.
Store the product in a cool and well-ventilated place. Keep it away from heat and ignition sources, and keep the container tightly closed.
The stated shelf life is 24 months from the production date.
Why Choose KN3378H?
KN3378H combines high gloss, excellent leveling, high solid content, strong fullness, high hardness, wear resistance, and reliable thick-film performance.
For manufacturers looking for a hydroxyl acrylic resin for automotive coatings, KN3378H is especially suitable for electric vehicle, motorcycle, helmet, and automotive refinish clear coat applications.
Contact the Kenxon technical team with your substrate, curing conditions, target gloss, film thickness, and resistance requirements to evaluate KN3378H in your formulation.