Stabilization masterbatches for Automotive
Addcomp is renowned for its excellent stabilization masterbatches for use in long-glass fiber-reinforced (LFT) composites and in glass mat thermoplastic (GMT) applications for the automotive industry.
Almost every car brand in the world relies on Addcomp for stabilization masterbatches.
Plastic exterior and interior parts have made major contributions to the automotive industry’s effort to reduce vehicle weight and thereby improve fuel economy. Automotive applications must meet strict requirements for impact strength, for temperature stability, and for UV resistance. Stabilization masterbatches are used to improve the properties of plastic parts to meet these stringent criteria.
Improving temperature resistance
Organic materials degrade in the presence of oxygen, forming peroxides, alcohols, ketones,aldehydes, acids, and other reaction products. The process is assisted and accelerated by the presence of energy (such as mechanical stress, heat, or light) and metals (such as catalyst residue, impurities, or co-additives).
Oxidation can affect appearance or performance properties, causing discoloration, surface roughness, or decreased tensile strength, for example. And the oxidative degradation of hydrocarbons proceeds auto-catalytically:
Stabilization additives can minimize the oxidation process by:
- Reducing the formation of aldehydes, ketones, and colors
- Alkyl radicals can be effectively terminated by vitamin E, lactone, or hydroxyl amine
- Radical scavengers can suppress auto-oxidation
Most polyolefins contain one or more anti-oxidants at levels between 0.05 and 0.10%:
- Primary anti-oxidants such as hindered phenols are generally radical scavengers or hydrogen donors, which can ensure long-term polymer protection
- Secondary anti-oxidants such as trivalent phosphorous compounds typically decompose hydroperoxide. They ensure stabilization during the processing of polyolefins and protect the primary anti-oxidants against decomposition
There are standard tests to demonstrate that a stabilized polyolefin meets automotive requirements:
- Long term heat-stabilization testing: exposure in a calibrated oven for a minimum of 1000 hours at 120˚C, 140˚C or 150˚C
- Mechanical testing: impact resistance using Izod or tensile-strength regimes
Since processing methods and raw materials as PP and glass can highly influence properties, testing should be done on finished products rather than on components or intermediates. Addcomp’s in-house laboratory is capable of conducting various relevant tests.
Increasing impact strength
Addcomp’s stabilization solutions for LFT composites and glass mat thermoplastics in automotive applications can be supplemented with PRIEX® coupling agents to improve the mechanical properties of finished parts.
PRIEX® coupling agents are characterized by:
- Very high levels of grafted maleic anhydride (MAH), which can provide:
- Very high reactivity and good wetting for the best mechanical property performance,
- cost reduction through lower levels of additive consumption
- Very low levels of free MAH in PRIEX resins after grafting means:
- Ultra-low odor,
- Ultra-low volatile organic compounds (VOCs) and emissions
- Minimal interaction between free MAH and filler
Using PRIEX resins for coupling in glass-fiber reinforced composites improves adhesion between the glass and polymer matrix:
The left-hand photo shows a glass composite without PRIEX coupling agent; in the righthand photo, PRIEX resin is used for coupling. This comparison clearly shown that the PRIEX additive produces a glass-polymer matrix that is more highly condensed, and that the glass is better integrated into the polymer matrix, thereby increasing the mechanical properties of the composite.
The benefits of applying PRIEX coupling agents for LFT composites was also demonstrated by an experiment study executed at Fraunhofer ICT (Pfinztal) for 3 different glass concentrations (20%, 30% and 40%):
LFT properties as a function of coupling agent concentration:
The benefits of employing PRIEX coupling agents in LFT composites was also demonstrated by a study conducted at Fraunhofer ICT (Pfinztal) using three different glass concentrations: 20%, 30% and 40%.Testing was done with samples of four compounds based on PP (LGF 8000). Each contained 2% of Addcomp’s ADD-VANCE® THC 453 black stabilization masterbatch, but the levels of PRIEX coupling agent varied as described:
- Sample A: 2 wt% ADD-VANCE stabilizer, with no coupling agent
- Sample B: 2 wt% ADD-VANCE stabilizer, with 0,6 wt% coupling agent
- Sample C: 2 wt% ADD-VANCE stabilizer, with 1,0 wt% coupling agent
- Sample D: 2 wt% ADD-VANCE stabilizer, with 1,6 wt% coupling agent
A PRIEX coupling agent was used in these masterbatches. The glass roving used was Saint Gobain Vetrotex P319.
The graphs below clearly show how the use of PRIEX coupling agent increased the mechanical properties of the LFT materials.
Extensive research and conclusive test results have enabled Addcomp to establish an unmatched depth of knowledge that supports our recommendation of “one-pack” masterbatch solutions for automotive polyolefins.
- For non glass-fiber-reinforced polyolefins, the most effective masterbatches are:
- ADD-VANCE® TH 130 anti-oxidant for processing and long-term heat stability
- ADD-VANCE® THC 453 (Black) anti-oxidant for processing, long-term heat stability (1000 hours at 150 °C)
- For glass-fiber-reinforced polyolefins the most effective masterbatches are:
- ADD-VANCE® THC 723 (Black) anti-oxidant for processing, long-term heat stability (1000 hours at 140 °C), and improved glass-fibre adhesion (with PRIEX coupling agent)
- ADD-VANCE® THC 732 (Black) anti-oxidant for processing, long-term heat stability (1000 hours at 150 °C), and improved glass-fibre adhesion (with PRIEX coupling agent)
- ADD-VANCE® THC 831 (Black) anti-oxidant for processing, long-term heat stability (1000 hours at 120 °C), and improved glass-fibre adhesion (with PRIEX coupling agent)
To start development of a “one-pack” masterbatch for your specific automotive application, please contact us.