Temperature and humidity are important environmental factors that affect the performance of adhesives. They play a crucial role in the application of adhesives, directly affecting their curing, bonding strength, durability, and reliability. Here are several aspects of how temperature and humidity affect adhesives:
1、 The influence of temperature on adhesives
The influence of temperature on adhesives is mainly reflected in curing speed, bonding strength, toughness, and durability.
How do temperature and humidity affect adhesives
(1) Curing process
High temperature: High temperature can accelerate the curing reaction of certain adhesives (such as epoxy resin, polyurethane, etc.). Most thermosetting adhesives cure faster at higher temperatures, which is very useful in some fast-paced industrial processes. However, excessively high temperatures may cause excessive reaction or incomplete curing of the adhesive, affecting its final performance.
Low temperature: At low temperatures, the curing process of adhesives usually slows down, and some adhesives may not fully cure, resulting in insufficient bonding strength. Especially thermosetting adhesives, their curing speed and performance will significantly decrease at low temperatures. Low temperature may also make the adhesive more viscous, affecting the operability of glue application.
(2) Adhesive strength and toughness
High temperature: At high temperatures, the bonding strength and stiffness of many adhesives will weaken, especially thermoplastic adhesives, which are prone to softening or plasticization, leading to a decrease in bonding strength. Some adhesives may fail when the temperature exceeds their tolerance limit.
Low temperature: Low temperature may cause some adhesives to become brittle, reducing their bonding strength and toughness. Especially for rubber based adhesives and other low-temperature curing adhesives, they may become prone to cracking in cold environments.
(3) Thermal expansion and contraction
Temperature changes: Temperature changes can cause differences in the thermal expansion coefficients of adhesives and substrates, which may lead to stress concentration at the bonding interface and affect the bonding strength. For example, when the temperature rises, the substrate may expand, while the adhesive may shrink, leading to cracking or detachment of the bonding interface.
2、 The influence of humidity on adhesives
The influence of humidity on adhesives is mainly reflected in the curing, adhesion, weather resistance, and aging process of adhesives.
How do temperature and humidity affect adhesives
(1) Solidification reaction
High humidity: When the humidity is high, certain adhesives (such as polyurethane, silicone, etc.) may absorb moisture, accelerating the curing reaction. Especially for wet curing adhesives such as silicone and polyurethane, they require moisture as a catalyst for the curing reaction.
Low humidity: Low humidity may slow down the curing process of moisture cured adhesives, resulting in incomplete cross-linking of the adhesive during the curing process and affecting its final bonding effect.
(2) Adhesive strength and aging
High humidity: High humidity environments may lead to a decrease in the bonding strength of certain adhesives, especially those that are sensitive to water, such as certain hot melt adhesives and acrylic based adhesives, which may absorb moisture under humid conditions, resulting in performance degradation. In addition, high humidity environments may accelerate the aging process of adhesives, leading to a decrease in their mechanical properties and adhesive strength.
Low humidity: A low humidity environment may cause some adhesive surfaces to dry out, affecting their surface adhesion, especially for certain adhesives that require moist surfaces (such as water-based adhesives). In addition, insufficient humidity may also affect the curing state of the adhesive, resulting in unstable performance.
(3) Corrosion and Decay
High humidity: In humid environments, the accumulation of moisture accelerates the chemical reaction between the adhesive and the substrate, especially on metal substrates. Moisture may cause corrosion, which in turn affects the bonding effect. In fields such as automotive and electronics, moisture poses a higher risk of corrosion to electronic components, therefore it is necessary to use adhesives with high waterproof and moisture resistance.
Low humidity: In low humidity environments, certain components in adhesives may become too dry, causing them to become brittle or lose elasticity, thereby reducing their long-term performance.
3、 The combined effect of temperature and humidity
The changes in temperature and humidity often occur alternately, and they work together to affect the performance of the adhesive. For example, in high temperature and high humidity environments, adhesives may experience softening, expansion, moisture absorption, and other phenomena, which in turn affect their bonding strength and stability; In low temperature and low humidity environments, adhesives may become brittle, incompletely cured, or exhibit other unstable characteristics. Therefore, optimizing temperature and humidity control, selecting suitable adhesive products, and conducting necessary environmental adaptation are necessary to ensure that adhesives perform at their best in practical applications.
summary
The effects of temperature and humidity on adhesives are multifaceted, and understanding their mechanisms of action can help us choose suitable adhesive products and ensure their stability and reliability in different application environments. Therefore, in the use of adhesives, in addition to paying attention to the characteristics of the product itself, special attention should be paid to the temperature and humidity factors in the usage environment, and corresponding optimization measures should be taken. For more knowledge about adhesives, please continue to follow Elaplus.
Tags: Humidity · Influence of humidity and temperature on adhesives · Adhesive
