Prepreg

Prepreg materials being used
Prepreg is the common term for fabric reinforcement that has been pre-impregnated with a resin system. The resin system is typically an epoxy and already includes the proper curing agent. As a result, it’s ready to lay into a mold without the addition of resin or the steps required.
The Carbon and Fiberglass Prepregs offer a number of specific advantages.

The term “prepreg” refers to woven or unidirectional fibers pre-impregnated with a thermoset polymer matrix, such as epoxy, BMI, cyanate ester, phenolic, etc. The fibers used in prepreg include glass fibers, basalt fibers, carbon fibers and aramid fibers. Prepregs are available for nearly every application with a wide variety of resin systems. The proper curing agent is already included within the resin systems, therefore, the prepreg is ready to lay up into the mold.  Pressure and heat are then used to cure the laminate.

The impregnation process allows the precise control of fiber to resin ratio, as well as, ply thickness. Excess resin is removed from the reinforcement and a partial cure results in a pliable state known as a B-stage. As heat activates the curing process, prepregs in the B-stage require refrigeration for storage and shipment.

There are some advantages as well as disadvantages to the use of prepregs.

Advantages:
Repeatable and uniform: As impregnation is performed under strict controlled environments, resin content and ply thickness will be uniform.

Less mess and waste: Unlike hand layup resin cups, drips, hand rollers and cleanup are not issues when dealing with prepreg materials. As prepregs can be handled at room temperatures, you are no longer racing against the clock to avoid the resin from setting before your work is complete.

Lower cure times: Unlike wet lamination which can require up to 5 days to cure, prepreg cures are measured in hours.

Maximum strength: Even applying vacuum bagging, wet layup seldom will allow resin contents < 50%. Prepregs have the desired resin content built in.

Better looking parts: With the elimination of air bubbles, prepregs allow smooth glossy surfaces more easily than with hand laminated parts.

Disadvantages:
Usable Shelf Life: As a prepreg is a catalyzed material, shipping and storage in refrigeration are required.

Cost: # for # prepreg materials are more costly than those used in wet lamination. The net cost of part manufacture need not be so.

Heat needed: A heat source and vacuum bagging are needed to properly cure prepreg materials. While most fabricators will employ the use of an autoclave, there are several out of autoclave (OOA) and Vacuum Bag Only (VBO) techniques that are used.

Applications
There are many applications that benefit from the use of prepreg materials These include aerospace, racing, sailing and boat building, sporting goods medical applications such as prosthetics, wind turbines, and more.

Processing
As prepregs cure at elevated temperatures, they can be processed using an autoclave or hot pressing. The best quality is achieved using an autoclave. Combining pressure and vacuum results in high fiber volume and low void content.

Out of Autoclave
Advances in out of autoclave (OOA) processing continue to improve performance and lower cost for composite structures. Vacuum bag only (VBO), can deliver less than one percent (1%) void content required for primary structures in the aerospace industry.

 You can find some of the prepreg materials that we offer here, or contact us to speak with a technical sales rep to help determine the best material for your needs.

ProductDescriptionCURE TEMP (°F)SERVICE TEMP (°F)TG (°F)
106/8Flame retardant, self-adhesive prepreg
MEETS
FAR 25.853
MIL-A-25463
MMM-A-132		250 – 320 °F180 °F250 – 300 °F
1101General purpose sandwich and laminating adhesive prepreg.250 – 320 °F200 °FLess than 250 °F
1102Long out-time adhesive prepreg.250 – 320 °F180 °FLess than 250 °F
1106Flame retardent sandwich and laminating adhesive prepreg.
MEETS
FAR 25.853		250 – 320 °F180 °FLess than 250 °F
117-1Flame retardant high toughness system.
MEETS
FAR 25.853
NASA Out-gassing		250 – 320 °F200 °F250 – 300 °F
301Industry standard for 30 years. Toughened system with controlled flow.250 – 320 °F200 °F250 – 300 °F
Download Data Sheet
301TDerived from 301 with optimized semi-transparent aesthetics.250 – 320 °F200 °F250 – 300 °FDownload Data Sheet
304-1Highly toughened system with good impact resistance250 – 320 °F200 °F250 – 300 °F
Download Data Sheet
307Specifically designed for thick structures with low exotherm.250 – 320 °F200 °FLess than 250 °FDownload Data Sheet
316Flame retardant system designed for electrical applications.
MEETS
UL 94 V-0		250 – 320 °F180 °FLess than 250 °F
Download Data Sheet
321High Tg with B-basis allowables.
MEETS
AGATE B-Basis Allowables		250 – 320 °F250 °F250 – 300 °F
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350General purpose high temperature cure system.Greater than 320 °F270 °FGreater than 300 °FDownload Data Sheet
4030FST system with low heat release properties.
MEETS
FAR 25.853		250 – 320 °F200 °F250 – 300 °FDownload Data Sheet
4035Snap cure FST system with low heat release properties.
MEETS
FAR 25.853		250 – 320 °F200 °FGreater than 300 °F
4565HTToughened bismaleimide (BMI) system with our highest Tg to date.Greater than 320 °F450 °FGreater than 300 °F
4708OOA processable, highly toughened system with NCAMP data.
MEETS
NCAMP Database		250 – 320 °F250 °F250 – 300 °FDownload Data Sheet
5300-1Low temperature variable cure system with long out-time.Less than 250 °F200 °F250 – 300 °F
6600OOA processable, highly toughened high temperature cure system.
DMS 2224 (not qualified to QPL)		Greater than 320 °F350 °FGreater than 300 °F
Download Data Sheet