Alkali-free Chopped Strand Mat: Classification And Performance Analysis
Alkali-free chopped strand mat (CSM) is a key reinforcing material in the manufacture of fiberglass reinforced plastics (FRP). Its production process involves: chopping alkali-free "E" glass fiber filaments into fixed-length fibers; uniformly laying these fibers on a moving conveyor belt using an airflow system; applying an adhesive (polyester powder or PVAc emulsion); and finally curing at a temperature before winding into a continuous mat sheet.
Classification and Manufacturing Process
Based on the type of binder, chopped strand mat is divided into two categories:
1. Powdered Mat
Binder: Polyester powder
Process: Fiber chopped → Spraying polyester powder → Drying → Cold rolling and setting
Characteristics: Loose fiber surface, binder is granular (visible to the naked eye) Fast resin penetration (impregnation time ≤100s, penetration time ≤40s) High tensile strength (≥100N), widely used
Disadvantages: Layer dust, dry fibers are prone to detachment
2. Emulsion Mat
Binder: PVAc emulsion
Process: Fiber directly sprayed with PVAc emulsion → Drying → Natural cooling and setting
Characteristics: Strong adhesion, very little dust, excellent environmental performance More uniform fiber distribution, high strength consistency (≥130N) Soft to the touch, suitable for manual layering.
Disadvantages: Poor resin impregnation (impregnation time ≤180s, penetration time ≤80s)
Application and Selection Recommendations
Powder mat application scenarios: Processes requiring rapid resin impregnation, prioritizing production efficiency, and accepting dust control requirements.
Emulsion mat application scenarios: Manual layering (hand lay-up, spraying), emphasizing environmental friendliness, product uniformity, and adhesion to complex curved surfaces.
Conclusion
The performance differences of chopped strand mats stem from the nature of the adhesive-polyester powder provides high impregnation efficiency, while PVAc emulsion enhances operability. Selection requires comprehensive consideration of process characteristics, efficiency requirements, and production environment to maximize the material's advantages.
