The main ingredients of MS nail-free glue

 

The main component of MS nail-free adhesive is typically a modified silane polymer, specifically a silane-terminated polyether (MS polymer). This component is key to the strong adhesion, excellent elasticity, and environmental friendliness of MS nail-free adhesive.

The following is a detailed description of the main components and their functions:

Base Polymer:

Silane-terminated polyether: This is the core component of the nail-free adhesive, typically comprising the largest proportion (up to 50% or more). It combines the flexibility of polyether with the strong adhesion and weather resistance of silane.

Function: Provides initial tack, final bond strength, flexibility (stress absorption), weather resistance (UV resistance, high and low temperature resistance, moisture resistance), and good substrate compatibility (ability to bond to a variety of different materials).

Filler:

Calcium carbonate, quartz powder, talc, etc.: Common inorganic fillers.

Function:

Increases the volume and consistency (thixotropy) of the adhesive, preventing it from flowing and facilitating application.

Reduces costs.

Increases the hardness and strength of the final cured adhesive.

Affects the color of the adhesive (usually white or gray).

Plasticizers:

Phthalates, non-phthalate plasticizers, etc.: Used to improve the flexibility and workability of the adhesive.

Function: Makes the adhesive softer and easier to extrude, and increases the elasticity of the cured adhesive layer. Modern environmentally friendly formulations tend to use safer non-phthalate plasticizers.

Thixotropic Agents:

Fumed silica, organic bentonite, etc.: Key ingredients.

Function: Gives the nail-free adhesive thixotropic properties—it is viscous and difficult to flow at rest, but becomes thinner and easier to extrude under shear (extrusion) during application. After extrusion, it quickly regains its consistency and maintains its shape without sagging. This is crucial for vertical surface application.

Adhesion Promoter:

Silane Coupling Agent: A very critical small molecule component.

Function: Serves as a “molecular bridge,” connecting one end to the polymer and the other end to form chemical bonds or strong interactions with hydroxyl groups or other groups on the surface of substrates (such as glass, metal, ceramic, and plastic), significantly enhancing the adhesive strength and durability of the colloid to various substrates.

Crosslinker:

Special silane compounds: Such as alkoxysilanes.

Function: During the curing process, they react with the active end groups (silane groups) of the base polymer to form a three-dimensional network structure, transforming the colloid from a paste to an elastomer and achieving final cure.

Catalyst:

Organotin compounds (such as dibutyltin dilaurate) or environmentally friendly alternatives: Used in small but critical amounts.

Function: Accelerates the hydrolysis-condensation reaction between the silane groups, moisture in the air, and the crosslinker, promoting cure.

Stabilizer:

Function: Ensures the stability of the colloid during storage, preventing premature curing or performance degradation.

Dehumidifier:

Function: Absorbs trace moisture in the packaging drum, extending shelf life.

Pigments:

Titanium dioxide (white), carbon black (black), etc.: Used for color matching, with common colors such as white, gray, and transparent being available to suit different decorative needs.

Core Curing Principle:
The curing of nail-free adhesive depends on moisture in the air (moisture curing). The reactive silane groups at the end of the core component, the silyl polyether, absorb moisture in the air under the action of a catalyst, undergoing hydrolysis to form silanols. These silanols further condense with each other or with the crosslinker to form a crosslinked Si-O-Si network structure (similar to the structure of glass). Simultaneously, the adhesion promoter forms a strong chemical bond with the substrate surface. This process transforms the paste-like colloid into a high-strength elastomer.