What is temperature stability? (Lamination)

In summary, the conversation discusses the properties of EVA lamination, specifically its temperature stability. It is mentioned that this refers to the ability of the laminate to resist warping and oxidative degradation when exposed to elevated temperatures. The use of antioxidants and the vinyl acetate content of the copolymer are also mentioned as factors that can affect thermal stability. To determine thermal stability, oven aging studies are typically conducted to test the polymer's physical properties at a given temperature.
  • #1
I'm doing some work on solar and I'm reading about properties of lamination materials, particularly EVA lamination.

Anyway, one of it's properties is 'temperature stability' but I can't find a clear definition of what this means.

EVA lamination is sandwiched in between a solar cell, so I can understand we wouldn't want the temperature of the EVA to get too hot, otherwise the heat might dissipate into the cell, making it less efficient.
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  • #2
I'm not sure, but this might refer to the ability of the laminate to resist warping when its temperature changes. Laminates can warp because they cannot expand thermally (significantly) in the directions of the reinforcement.
  • #3
In polymers, thermal stability refers to the polymer's resistance to oxidative degradation upon exposure to elevated temperatures over time. Chain scission due to thermal degradation results in the formation of free radicals, which further react with the polymer chain. The polymer's molecular weight distribution changes to wider, flatter distribution, impacting its physical properties. Most polymers are protected from this phenomenon by the use of hindered phenolic antioxidants. The hindered phenols are free radical traps that form stable products after reaction with the free radical. Phosphites are used in conjuction with the hindered phenols as a secondary mechanism against free radicals. Typical concentrations of antioxidant are on the order 1000 ppm, and the ratio of primary to secondary antioxidant is usually 2:1. The stabilty of the EVA will depend on the vinyl acetate content of the copolymer. Low VA content is about 7%, and the highest content is 28%.To be honest, I've forgotten which way the relationship goes, but my gut says high VA content copolymers are less thermally stable than low VA content copolymers.

Thermal stability is usually determined by oven aging studies. The polymer is placed in an oven at 105 C for a period of time. The polymer is tested for yellowness index, impact resistance, and tensile and elongation. periodically. With this data, you can tell how long service life would be at a given temperature before failure.

1. What is temperature stability?

Temperature stability refers to the ability of a material or system to maintain a consistent temperature over time, despite changes in ambient temperature or other external factors. This is important in various industries, such as food production, pharmaceuticals, and electronics manufacturing, as temperature fluctuations can affect the quality and performance of products.

2. How is temperature stability measured?

Temperature stability is typically measured by monitoring the temperature of a material or system over a period of time and observing any changes. This can be done using specialized equipment such as temperature sensors or thermal imaging cameras. The temperature stability of a material or system is often expressed as a range, such as +/- 1°C, to indicate the degree of variation that is considered acceptable.

3. What factors can affect temperature stability?

There are several factors that can affect temperature stability, including ambient temperature, humidity, air flow, and insulation. The type of material or system being monitored also plays a role, as some materials are more sensitive to temperature changes than others. In addition, external factors such as heat sources or direct sunlight can also impact temperature stability.

4. Why is temperature stability important in lamination?

In lamination, temperature stability is crucial for achieving consistent and high-quality results. This is because the bonding process relies on the melting and re-solidifying of adhesive layers, which requires a precise and stable temperature. Any fluctuations in temperature can result in uneven bonding, delamination, or other defects in the laminated product.

5. How can temperature stability be achieved in lamination processes?

To achieve temperature stability in lamination, various measures can be taken, such as using specialized equipment with precise temperature control, monitoring and adjusting the ambient temperature and humidity, and ensuring proper insulation and air flow. It is also important to choose materials and adhesives that are suitable for the desired lamination temperature and to follow proper lamination procedures to minimize temperature variations. Regular maintenance and calibration of equipment can also help maintain temperature stability in lamination processes.

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