Liquid Compression Molding

Hot Compression Molding:
In Hot Compression Molding a reinforcing glass mat and/or surface veil are cut to shape and laid into the lower half of a heated mold. Mold temperatures are typically between 130 – 200 C. A predetermined amount of partially polymerized thermoset resin is then poured over the glass mat. The upper mold half is then closed over the lay up and the resin is squeezed into the shape of the mold. Final Polymerization takes place under heat and pressure. In some situations the resin can be injected after the mold has been closed.

Cold Compression Molding:
In Cold Compression Molding the lay-up process is similar to hot Compression Molding but the polymerization process takes place under relatively low pressure, typically at 10-50 p.s.i. and at room temperature.

Superior R.T.M. Mats:

• N-700, Regular at 7%
This mat consists of densely packed fibers and is most often used to reinforce flat parts. N-700 provides a good surface but not as good as with Surmat. When molding multiple layers of N-700, care should be taken to ensure good mat wet out and that all air has been forced from within the mat.

• N-751, Regular at 6%
This mat consists of dense bundled fibers and is used to reinforce flat or semi-contoured parts. If surface appearance of the final part is a concern, this mat should be used with either Surmat or Surmat 100 SF surfacing veil.

• N-754, Regular at 7%
This mat is more open than N-751 and is used to reinforce flat or semi-contoured parts. If surface appearance of the final part is a concern, this mat should be used with either Surmat or Surmat 100 SF surfacing veil.

• N-758, Regular at 5%
This mat is the most flexible or drapeable mat available making it an excellent reinforcement for complicated or contoured parts. If surface appearance of the final part is a concern, this mat should be used with either Surmat or Surmat 100 SF surfacing veil.

• Surmat
This mat is an economical surfacing veil that provides a very good surface on parts, it also enhances resistance to corrosion under acidic conditions.

• Surmat 100 SF
This mat provides an outstanding critical surface for pigmented resins or post painting by forcing heavier fibers away from the surface, eliminating fiber bloom and raising a slight excess of resin to the surface. Surmat 100 SF also provides resistance to corrosion under acidic conditions.

Extra Surface Option
Conformat N-751, N-754 and N-758 may be purchased with an additional Surmat type veil already attached to one or both surfaces. See product specifications for details.

Binder Selection:
Regular binder is a polyester based soluble binder system. “Type 176” binder is a polyester based non-soluble binder system.

When selecting materials for an initial molding trial, examine the overall size and contour of the part. Select either N-751 or N-758 as the reinforcing mat. Mat weight is a function of the desired glass load and should be specified by the customer. See Superior Fibers application note 200.

The maximum width for a Compression Mold mat 78 inches. If the final part is to be molded with two (2) or more layers of reinforcement, it is often good design practice to alternate mat directions to impart more consistent strength to the part in both directions. When a more uniform strength single layer of material is required, N-921 or N-952 may be considered.

Reinforcing mat style material should be consistent on both sides from the middle. Unequal reinforcement construction has the potential to cause the part to warp.

When selecting roll width for a mat, the maximum part width should correspond to roll width and the minimum part width should be taken from the roll length.

And very importantly, we only use BoronFree ACR Glass in manufacturing our FRP mats. This is the top grade glass that resists corrosion and produces customer-winning quality parts.