Silicone glue vs. acrylic glue

Silicone and acrylic adhesives are the most common adhesives used in polyimide tapes. Polyimide tapes consist of two layers:

• the polyimide film and
• the adhesive that is applied to this film.

Although silicone adhesives are most commonly used for the adhesive layer, many applications require the tape to have an acrylic adhesive. The only way to understand why this is is to compare the two types of adhesives - silicone and acrylic.

Silicone adhesive - the properties

Silicone offers better elongation at break. It is used for electrical insulation of electrical equipment. Because it offers the highest heat resistance among adhesives, it is also commonly used for high-temperature insulation. For a better understanding, some properties of silicone adhesive tapes are listed below:

• Silicone is highly flexible at sub-ambient temperatures.
• It can provide consistent performance over a wide temperature range.
• It has very good aging and UV resistance.
• It can withstand high temperatures.
• Silicone also shows good resistance to polar solvents.

Acrylate adhesives – the properties

There are two types of acrylic adhesives:

• water based and
• solvent based.

Water-based acrylic adhesives dry more slowly than solvent-based adhesives. However, solvent-based acrylic adhesives usually have better resistance to other solvents, chemicals and water. Some of the properties of acrylic adhesives are as follows:

• Acrylic adhesives have adequate adhesion to a variety of substrates.
• It has good aging, transmission and UV resistance suitable for fiberglass applications.
• It also has reasonable temperature resistance but is not as good as silicone glue.
• It has lower stickiness, which means it will be less sticky after drying.

Silicone vs Acrylic Adhesive

Now that we know the properties of silicone and acrylic adhesives, we can move on to comparing the two types of adhesive.

Silicone adhesives can withstand a higher temperature range compared to acrylic adhesives. Acrylate adhesives tend to be more brittle and can therefore break even at extremely low temperatures. In general, acrylate adhesives adhere better at medium temperatures, i.e. in a temperature range between 0 °C and 100 °C. On the other hand, silicone adhesives have better adhesion at lower temperatures, ie below 0°C, as well as at higher temperatures, ie above 100°C.

So it seems that silicone adhesives are more standard and preferred for most applications. However, in some situations where silicone cannot be used, acrylic adhesives must be used. As for the point of less stickiness with pure acrylates, again there is an alternative for better performance. Modified acrylic or rubber adhesives can be used for better tack. Pure acrylic adhesives are often used for adhesive tapes that are used for bonding, sealing or surface protection.