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Fiberglass Combo Mat (also known as Fiberglass Combined Mat) is a high-performance composite reinforcement material engineered by integrating two key fiberglass forms: woven roving and chopped fiberglass strands (Chopped Strand Mat). Its unique structure is formed by randomly distributing precision-chopped fiberglass fibers on one or both sides of a woven roving base, then stitching the entire assembly together using high-strength organic fibers (such as polyester or polypropylene threads). This integration combines the directional strength of woven roving with the isotropic performance of chopped strands, creating a material that delivers balanced mechanical properties and exceptional processability.

The mat exhibits excellent compatibility with a wide range of thermoset resin systems, including unsaturated polyester (UP), vinyl ester (VE), phenolic, and epoxy resins. It is widely recognized for enabling rapid laminate buildup, reducing production cycles while enhancing the structural integrity of finished composite parts. This makes it a staple material in FRP pultrusion, hand lay-up, and RTM processes to manufacture FRP (Fiber Reinforced Plastic) across multiple industries.

Identification:

What are the key features of fiberglass combo mat? 

Integrated Construction: Two reinforcements in one product eliminates the need for separate layers of CSM and WR, reducing labor and potential for interlayer voids.

Excellent Wettability: The CSM layer acts as a resin distributor, facilitating rapid and thorough impregnation of the woven layer beneath.

High Strength-to-Weight Ratio: The woven roving provides high tensile and flexural strength, while the CSM contributes to impact resistance and laminate toughness.

Good Drape and Conformability: The CSM side allows the mat to conform well to complex curves and compound molds.

Balanced Properties: Provides a more isotropic strength profile than woven roving alone, but with higher strength than CSM alone.

Reduced Print-Through: The CSM layer helps mask the pattern of the woven roving on the finished surface, improving cosmetic appearance.

Controlled Weight and Thickness: Available in standardized weights, allowing for predictable laminate thickness and glass content calculations.

Product parameter：

What are the advantages and benefits of fiberglass combo mat?

Labor and Time Savings: Eliminates the step of applying two separate materials, significantly speeding up the laminating process.

Improved Laminate Quality: The mechanical needling bonds the layers, preventing delamination between the CSM and WR that can occur when layering separate products.

Reduced Resin Usage: The efficient packing and distribution can lead to more consistent glass-to-resin ratios compared to hand-layering, often in the range of 30-40% glass by weight.

Ease of Handling: The integrated product is easier to cut, position, and roll out than managing two separate rolls.

Versatility: Suitable for a wide range of applications, from simple flat panels to complex marine hulls.

Cost-Effective: While the raw material cost per kg may be higher than buying CSM and WR separately, the total installed cost (material + labor) is often lower.

What applications is fiberglass combo mat used for?

Marine & Offshore: Boat hulls, decks, bulkheads, and offshore platform components. ECR/ECT-glass combo mats are preferred for their corrosion resistance in saltwater environments.

Automotive & Transportation: Lightweight body panels, bumpers, headlight housings, and truck fenders. The mat’s high strength-to-weight ratio helps reduce vehicle weight and improve fuel efficiency.

Building & Construction: FRP panels (ceiling, wall, floor), cooling tower fills, water tank liners, and septic tanks. E-glass combo mats are widely used for their cost-effectiveness and durability.

Electrical & Electronics: Electrical junction boxes, switchgear enclosures, and transformer housings. The mat’s electrical insulation and flame-retardant properties (when paired with phenolic resin) meet industry safety standards.

Industrial Equipment: Chemical storage tanks, pump casings, and conveyor components. Corrosion-resistant ECT/ECR grades protect against harsh chemicals and industrial environments.

Sporting Goods: Canoes, kayaks, surfboards, and camping equipment. The mat’s lightweight and impact-resistant properties enhance product performance and user experience.

How to store and handle fiberglass combo mat? 

Proper storage and handling are essential to preserve the structural integrity and performance of Fiberglass Combo Mat:

Storage Environment: Keep in a cool, dry, and clean warehouse with temperature controlled at 15-35°C and relative humidity at 35-65%. Avoid direct sunlight, rain, and proximity to water sources, steam, or corrosive chemicals.

Packaging Protection: Maintain the original moisture-proof packaging (typically polyethylene-lined kraft paper rolls) until immediately before use. Damaged packaging should be repaired or replaced to prevent moisture absorption.

Stacking Requirements: Horizontal stacking is recommended, with a maximum of 5 rolls per stack for rolls with width ≥1200mm, and 8 rolls per stack for narrower widths. Place wooden pallets between layers to distribute weight evenly and avoid crushing the mat.

Shelf Life: Under optimal storage conditions, the shelf life is 18 months from the production date. For rolls stored beyond 12 months, inspect for signs of moisture absorption (e.g., stiffness, discoloration) before use.

Handling Precautions: Use forklifts or hoists with soft slings to move rolls; avoid dragging, dropping, or bending rolls excessively, as this may damage the stitching and cause fiber separation.

FAQ

Question 1: What is the regular width of fiberglass combo mat?

A: The width of our regular combo mat is 1040mm and 1270mm. We also export products with width of 1500mm to South America. The width can be customizable.

Question 2: Could you tell me more about three-layer fiberglass combo mat?

A: Yes, ECM450/800/450 is three-layer combo mat. The woven roving is in the middle. Chopped fibers are distributed both sides of the woven roving. The area weight of woven roving is 800g/m2, but the area weight of chopped fiber for one side is 450g/m2.

Question 3: Which side of fiberglass combo mat faces up/down? Does it matter?

A: Yes, it matters. The CSM layer should face UP (toward the laminator). This ensures the resin is applied to the distributive CSM layer first, which then efficiently wets out the woven layer beneath. Placing the woven side up can lead to poor wet-out and visible dry patches.

Question 4: Is the fiberglass combo mat compatible with thermoplastic resins, or only thermosets?

A: Our standard combo mat is optimized for thermoset resins (UP/VE/epoxy/phenolic). For thermoplastic applications (e.g., PP, PA), we offer a specialized thermoplastic-grade combo mat with a compatible sizing system. This grade features heat-resistant stitching threads (stable up to 280°C) and chopped fibers treated with maleic anhydride coupling agents to enhance bonding with thermoplastics. It is suitable for thermoplastic compression molding processes, such as automotive structural components.

Question 5: How does fiberglass combo mat compare to a separate layer of CSM and WR?

A:  Combo Mat: Faster lay-up, guaranteed layer bonding, consistent weight ratio, easier handling. Slightly less flexibility in tailoring individual layer weights.

Separate Layers: Allows for more design flexibility (e.g., different CSM weights between WR layers), potentially lower material cost, but slower, prone to interlayer bubbles, and requires more skill.

Question 6: Why do I sometimes see air bubbles trapped under the woven pattern of combo mat?

A: This is a common issue if the resin is too viscous or if the laminate is not properly rolled out. The CSM layer wets quickly, but resin can bridge over the "valleys" in the woven roving. Solution: Use a laminating roller (pin roller) aggressively to work resin into the weave, and ensure resin has adequate working time (pot life).