Why does MS nail glue become thicker and harder to extrude with age?
Why does MS nail glue become thicker and harder to extrude with age?
MS nail glue (silane-modified polyether glue) becomes thicker and harder to extrude with age. This is primarily due to changes in the chemical properties of the glue, the storage environment, and the stability of its components. The specific reasons are as follows:
1. Slow cross-linking reaction triggered by trace amounts of moisture
MS glue cures through a chemical reaction (hydrolysis and condensation) between the silane groups in the glue and moisture in the air, forming a cross-linked structure.
Even in unopened packaging, the glue may be exposed to trace amounts of residual moisture (e.g., if the packaging is not completely sealed or a small amount of moisture introduced during production). Over extended storage, this trace amount of moisture slowly triggers localized cross-linking of the silane groups in the glue, increasing molecular chain length and entanglement. Ultimately, this results in increased viscosity, thickening, and difficulty in extrusion.
2. Slow loss of volatile components
MS glue typically contains a small amount of volatile additives (such as diluents and plasticizers) to reduce initial viscosity and improve extrudability. During long-term storage, even if the packaging is sealed, these volatile components may slowly seep and dissipate through the tiny pores of the packaging material. As the volatile components decrease, the colloid’s “fluidity” decreases, and the remaining system’s viscosity naturally increases, making extrusion difficult.
3. The Impact of Storage Temperature
Temperature is a key factor in accelerating or retarding colloid changes:
High temperatures accelerate chemical reactions within the colloid (including the cross-linking reaction mentioned above) and the volatilization of volatile components, significantly shortening the colloid’s “stability period” and exacerbating thickening.
Low temperatures temporarily reduce molecular movement, but prolonged low temperatures can cause microscopic aggregation or crystallization of some components within the colloid (such as plasticizers and fillers), disrupting the colloid’s uniformity. Upon recovery, these aggregated components may not fully disperse, further increasing the system’s viscosity.
Frequent temperature fluctuations in storage can repeatedly irritate the colloid’s internal structure, accelerating its destabilization and ultimately leading to thickening. 4. Decreased physical stability of colloid components
MS glue is a multi-component mixed system (including a polymer matrix, fillers, pigments, additives, etc.). Its physical stability (e.g., dispersion uniformity) will gradually decline over time:
During long-term storage, dense fillers (e.g., calcium carbonate, talc) may slowly settle or partially separate from the polymer matrix, resulting in a “rigid structure” within the colloid, manifesting as overall thickening and poor fluidity.
As additives (e.g., stabilizers) in the colloid lose their effectiveness over time, the compatibility between components decreases, potentially leading to microphase separation and further increasing the viscosity of the system.
Summary
The core reason why MS nail glue thickens over time is that, during long-term storage, slow crosslinking caused by trace amounts of moisture, loss of volatile components, accelerated reactions due to temperature fluctuations, and decreased component stability all contribute to increased colloid viscosity. Therefore, to delay this phenomenon, it is recommended to store MS glue in a cool and dry place (temperature 5-30℃ is best) and try to use it within the shelf life (usually 6-12 months). It should be used up as soon as possible after opening to reduce the time it comes into contact with air.