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Why is the Right Resin Important?

In the early 1980's, the marine composites industry faced incredible corrosion problems. We believed the blistering was the result of corrosion in the laminate (water is an excellent solvent), and by using an epoxy-based vinyl ester resin behind the gel coat, the blistering could be eliminated. Obviously, time has proven us correct.

Epoxy-based vinyl esters were invented by Interplastic Corporation thirty years ago and their remarkable corrosion resistance and physical properties make these resins hallmarks of today's resin industry.

How it Works
A marine vinyl ester decreases the amount of water getting into the laminate via osmotic pressure and it provides an inert barrier. By laying down a skin coat of vinyl ester behind the gel coat, or by completely replacing the regular resin used in the laminate with the Interplastic vinyl ester, the laminate is too corrosion resistant to be attacked.

Hanging in There
Back in the 1980's, vinyl ester resins were difficult to use in spray-up applications. That prompted us to create our pre-promoted and thixotropic vinyl ester laminating resins. These resins get their "sticky characteristics" from their epoxy "backbone." Simply said, the resins stay put, don't require special equipment or handling and their adhesion properties also allow them to overcome any flaws or contamination on the gel coat surface that could cause blisters to occur within the first year.

Durable: Two Different Benefits
When a hull laminate is made using a marine vinyl ester, there is a huge improvement in its physical properties versus those of a traditional laminating resin.

Vinyl esters are vastly more capable of resisting cracking due to flexing of the composite. Why is this important?  A boat hull flexes (bends) in and out tens of millions of times in its lifetime. Every wave, every bump, causes a tiny flexing movement and this causes fatigue, and fatigue is cumulative. The reality is that marine vinyl esters are thousands of times better in fatigue performance than the "old stand-by" laminating resins.  The benefits?  The laminate's durability equates to longer hull life. It also means that these resins help protect your customers' investment.

Show Me the Results

This is a pretty graphic example of how well marine vinyl esters protect a hull laminate from water attack and blistering.

The original research on fatigue resistance was done on laminates and castings, with the best in neopentyl-glycol-based gel coats, and under very precise conditions. Laminates mimicking a boat hull were tested by immersion, at two temperatures that were higher than ambient. We figured this would accelerate the testing and the results would be available in a reasonable amount of time. Our lab tests proved to be accurate, and throughout the ensuing years, marine vinyl esters have proved themselves well in the field.

The technical paper "A Study of Permeation Barriers to Prevent Blisters in Marine Composites and a Novel Technique for Evaluating Blister Formation," as well as the other papers referenced here, can be read in their entirety by clicking on their icons at the end of this article.


This table shows the incredible resistance to weight gain (the absorption of water during attack on the laminate).  When you compare the information in the vinyl ester columns to those of the other resins, you will see that the marine vinyl ester remains remarkably constant over time while the other polyesters are beginning to fail.

There's that durability word again.

Strength is an Undeniable Benefit
(Stress/Strain Curve in Flexural TestTensile Test”)

Look at these graphs carefully. If you describe the area under the curve as the "Amount of Toughness," imagine how much more energy it would take to break the vinyl esters in these tests! This translates directly to an exceptionally strong composite for your boat. By the way, marine vinyl esters also wet-out and bond tighter to the glass reinforcements, which also contribute to the laminate's strength.

Says Who?
The hard -driven bass boat is an excellent example of "proof in the field."  These boats demand the utmost in fatigue resistance yet also require the lightest, most sophisticated laminate possible. Marine vinyl esters are always up to the task.

A well-known sailing yacht manufacturer has been using marine vinyl esters for 15 years and has a ten-year hull warranty against blistering on every boat.  They're still waiting for their first claim.

Sleek, durable kayaks and canoes made by We-no-nah Canoe. Powerful, exciting off-shore racers crafted by Cigarette, Fountain and Advantage. Glamorous mega yachts by Christensen. Every laminated hull benefits from marine vinyl esters. Explore our marine case histories to get the real specifics.

Interplastic Corporation's technical paper, "A Study of Permeation Barriers to Prevent Blisters in Marine Composites and a Novel Technique for Evaluating Blister Formation,"  as well as the other papers referenced here, can be read in their entirety by clicking on the “Technical Papers” link on the navigation bar below.

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