TAGS: Automotive Coatings Sustainability / Natural Coatings Acrylic Coatings
This is a sponsored article by Kuraray.
The automotive industry is undergoing rapid and regular developments over time. The growth and profits associated with this industry are higher but the demand for new formulations is indeed essential for the development and practically required ideas.
Automobile exterior and interior coatings need to be stable with the temperature and weather changes. The coatings require better transparency, high surface hardness, durability, and flexibility to assure better results. The increase in design flexibility, productivity, and reduced weight make the coatings part challenging.
Need for Acrylic Resin Modifiers
Acrylics are used in many applications due to their excellent transparency and durability. However, there are sustainability issues that arise when certain features of acrylics require improvement and modifications.
The automotive industry has got modifiers that are nitrogen and sulfur-free, act as reactive diluents, and are highly functional. These are added to the acrylics to change their properties and give beneficial results in comparison to the other modifiers, such as HDDA. There are some exclusive features required in automotive coatings that need a specialized modifier which:
- Is suitable as a reactive diluent for hard coatings.
- Works as a UV curing accelerator.
- Imparts flame retardancy, anti-scratch properties, low curing, and chemical resistance.
In this article, let's focus on the key features of Isoprenyl methacrylate (IPEMA), a compatible acrylic resin modifier that qualifies as a suitable option over HDDA for the formulation of automotive coatings.
Main Characteristics of IPEMA by Kuraray
Isoprenyl methacrylate (IPEMA) is an acrylic resin modifier for automotive applications. It is used for versatile
hard coating applications and automobiles are one of the practical segments for IPEMA.
Key features of IPEMA:
- Nitrogen & sulfur-free multifunctional crosslinking agent, UV curing accelerator & reactive diluent
- Highly stable, low viscosity, and low toxicity
- Highly functional and versatile for hard coatings such as automobiles
- Easy reaction with phosphites and acrylics to impart flame retardancy to UV coatings
- High anti-scratch resistance and low-curling agent
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Implementation in Automobiles: IPEMA vs. HDDA
As a Reactive Dilutant for Hard Coatings
The major issue with HDDA dilutants is that they work with one-step cross-linking that even includes oxygen inhibition which results in curling by curing shrinkage. There is no proper balance between hardness and flexibility that is required in many practical coating applications.
However, in the case of IPEMA, UV curing occurs and there is
stepwise crosslinking that reduces the stress and realizes both hardness and flexibility. It has a perfect application in vehicles for decorative films, exterior coatings, and even the parts requiring stable and
hard coatings that do not get affected over time.
Figure 1: Issues with General Process (HDDA) and the Changed Reactivity and Cross-linking with IPEMA
Low Curling Properties
All matrix resins tend to shrink during the cure cycle due to thermal variations and cure shrinkage properties. However, IPEMA has
low curling properties which is highly suitable for hard coatings required for automobile applications. The coatings remain consistent with temperature variations and the shrinkage is controlled which makes it suitable for vehicle coatings. The image below shows these processes in a detailed manner.
Figure 2: Low Curling Properties of IPEMA Hard Coatings
High Scratch Resistance
Scratch resistance is essential for automobile coatings. Hard coatings are formed on various plastic regions and these become
brittle due to low flexibility. Hardness and
flexibility are required for enhanced durability and sustainability. IPEMA fulfills the purposes in a way to render enhanced durability and sustainability with its anti-scratch feature for automobile coatings.
IPEMA offers increased durability with its
scratch-resistant properties. This is one of the primary challenges faced in acrylic products that could be caused due to any sources. Scratches can be caused by abrasion or general wear and tear. IPEMA is a preferred solution for hard coatings over traditional diluents, like HDDA.
The results of the scratch resistance test showed that IPEMA has proven itself as a competitive option in comparison to the traditional coating additives. It can work proficiently for interior coatings of automobiles and even act as an excellent substitute for glass. There are many areas where scratch resistance is very essential for automobiles and IPEMA works efficiently for this most important part of coatings on vehicles.
|
HDDA |
IPEMA |
| Main agent |
DPHA |
60 |
60 |
| Diluents |
HDDA  |
40 |
|
|
IPEMA 
|
|
40 |
| Initiator |
1-hydroxycyclohexyl-phenyl ketone (Omnirad® 184) |
3 |
3 |
| Property |
Steel-wool scratch resistance |
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Scratch Resistance Test Results for IPEMA in Comparison to HDDA
Low Viscosity and UV Curing Acceleration
IPEMA is an acrylic modifier that can lower the
viscosity which results in uniform application. The feature of UV curing acceleration reduces oxygen inhibition in coatings.
Figure 3: IPEMA: Unique Monomer that Inhibits Oxygen
The
acceleration of UV curing in air improves the hardness of coatings and
chemical resistance. by cross-linking reactive groups. Fast curing and high elongation are offered by IPEMA which results in better acrylic coatings.
Figure 4: UV Curing Process with the Formation of the Cured Film
Flame Retardancy without Using Halogens
Acrylics are flammable in nature and flame retardants are added to protect them from fires. Non-halogen type flame retardants are required for sustainability as these are safe for the environment and health. With the use of IPEMA, acrylic sheets can become non-flammable without using halogens. It doesn’t require catalysts for speeding up chemical reactions.
Figure 5: Flammability Test Method
Linkeage Between Phosphites and Acrylics to Impart Flame Retardancy
This feature of IPEMA can suppress dripping and bleed-out in a simple way. Phosphite can be effectively introduced into the polymer by IPEMA by making it a suitable modifier for hard coatings.
Figure 6: Inclusion of Phosphite Into a Polymer with IPEMA
Conclusion
IPEMA is an excellent cross-linking agent by Kuraray that has proven capabilities for hard coatings. The prime features make it a compatible acrylic resin modifier for the coatings used in automotive parts. The features mentioned above make it a perfect fit for hard coatings and the versatility it offers is the reason behind making it most suitable for high-end coating applications.
Whether it is the interior coatings, decorative films, exterior hard coats, or any parts of the automobiles requiring anti-scratch, low curling, flame retardancy, UV curing, or other properties, IPEMA is proven to the robust coatings that last for a long span.
Discover the technical data sheets of Kuraray products.
» IPEMA: A multi-functional crosslinking agent, UV curing accelerator and reactive diluent for hard coatings
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» DPNG: A nitrogen- & sulfur-free antioxidant and accelerator for UV ink and coatings
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