Thermoset plastics – how to improve its durability and color stability?

Thermoset plastics, with thermosetting resin as the main component. It is a plastic that forms products by cross-linking and curing process with various necessary additives. In the early stage of the manufacturing or molding process it maintains the liquid. After curing it is insoluble. In other words, it can no longer melt or soften.

What is the difference between thermoset plastics and thermoplastics?

Thermoset plastic can soften the flow when it is first heated to a certain temperature. Then a chemical reaction will be resulted ( A cross-linking reaction), which lead to solidifies and hardens. This change is irreversible!

The resin molecular chains in thermoplastic polymers are linear or branched chains. It can soften and flow when heated, and the process of cooling and hardening is a physical change, in other word it’s reversible.

What are the main types of Thermoset plastics?

• Phenol-formaldehyde Resin (PF); it has advantages of easy molding, good dimensional stability and above all, good electrical insulation. It results in good heat resistance as well. The main applications are electrical receptacles and coatings & adhesives.
• Animoplastics (AF); it has advantages of hard plastic, scratch resistant and colorless and translucent. Main applications are industrial parts, medical instruments, decorative materials and heat & sound insulation materials.
• Urea-formaldehyde resin (UF); it is colorless and transport and good heat resistance. Together with high hardness and good mechanical properties it has great advantages for applications like tableware and furniture.
• Melanine-formaldehyde resin (MF); advantages of high hardness, wear resistance and flame retardant. Excellent for applications as coatings, decorative panels, molding materials and adhesives.
• Epoxy resins (EP); Excellent bonding effect, electrical insulation and resistant to chemicals corrosion. With these advantages the main applications are for example adhesives and coatings.
• Organic silicon resin; advantage of electrical insulation and heat resistant and water aversion. Therefor, it is interesting for electrical insulating material.
• Unsaturated polyester resin; advantages of low pressure molding and glass fiber reinforced type. Main applications are Fiberglass Reinforced Plastic (FRP) manufacturing and potting materials.
• Polyurethane; this is light foamable and easy process. As a result, main applications are furniture, packaging and coatings.

How to improve the durability and color stability of thermosetting plastics

Although most thermosetting plastics have the advantages of heat resistance, good electrical insulation, but with the development of industrial technology, more and more areas put forward higher requirements for color retention and durability.

First important improvement can be made with UV absorbers. We will highlight two of our key UV absorbers for thermoset polymers:

The Omnistab UV 1 is mainly aimed at UV B band protection. Omnistab UV 1 is the product you need if your are working with thermosetting plastics with high cost performance. Like polyurethane, adhesives, foam and other thermoset molding materials.

The Omnistab UV 1577 is excellent for systems with high requirements for product transparency and color stability. Such as high-end furniture decorative board, car decorative materials and artificial jewelry.

Secondly, suitable antioxidants can greatly extend the service life and durability. Especially when you use them in combination with UV absorbers.

The best way is to add a hindered phenolic antioxidant, Omnistab AN 1076, with a macro-molecular auxiliary antioxidant, Omnistab AN 626. It not only plays a protective role in the process, but also play a lasting role in the use stage. It will alleviate the photo oxygen aging degradation of the material.

If you want to know more about this topic or if you have a specific inquiry related to your production process, please contact us!

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