Fairlawn, Ohio – Kraton Performance Polymers Inc. has improved its Cariflex IR latex so it may expand its usage potential, and the company began to discuss its development work on the material's second generation.
Some of the changes in processing that can be done with Kraton's polyisoprene latex, marketed under its Cariflex IR brand, will help those who make synthetic gloves with the elastomer tackle issues regarding Type IV allergies, according to Philippe Henderson, global market development director for Cariflex polyisoprene products. He gave a paper at the recent International Latex Conference in Fairlawn on the topic and talked about it in more detail after the presentation.
The synthetic rubber has been commercialised for about a decade, and it helped deal with the more severe Type I latex allergy, which brings about immediate reaction and may require emergency treatment for anaphylaxis, Henderson said.
But now that the Type I allergy is more in control, he said customers are asking for solutions to combat Type IV, which is a delayed-type hypersensitivity normally caused by the chemicals used to make gloves, rather than an allergy to proteins from the natural rubber.
One way to do that is to use fewer or no cure chemicals, potentially reducing risks associated with the Type IV allergies, according to Henderson.
Besides these improvements, as synthetic gloves have grown to where they now account for roughly half of the US surgical glove market – powdered and powder-free NR gloves make up the rest – customers are looking for ways to cut costs.
Ways to do this, he said, include making the processing window more forgiving and reducing curing temperatures. “Reducing curing temperature can be useful because not all the companies have ovens that can go very high in temperatures,” Henderson said.
The rise in synthetic gloves in the surgical market has been an interesting evolution, he said. The gloves are made of either polychloroprene or polyisoprene, but the latter – which includes the Cariflex line – has the greater share.
When a new product comes out and does well, it normally has a sharp growth curve and then levels off, Henderson said. The surgical glove market, though, is conservative as surgeons aren't quick to embrace change in such a critical product line until success is proven.
“You needed the new generation of surgeons coming in, and they have used synthetic gloves,” he said. “So it hasn't hit the plateau. It just keeps growing at that same straight line rate.”
The Cariflex IR also can have changes that will aid in condoms, where acceptance is all about feeling and perception, Henderson said. “The transparency of the film is something that matters for the users,” he said. “Often, the films aren't very transparent because they have zinc oxide in the recipe. We have developed options that are zinc oxide free so you have this chance to make more transparent films.”
New generation Cariflex
For the first time at the conference, Kraton introduced its Cariflex 2GL, a second generation latex product that the company claims provides similar features as the original Cariflex IR, but with potential processing characteristics of thermoplastics.
It is a styrene-modified polyisoprene rubber having low styrene content and, based on performance requirements of the final products, Kraton said it can be used to make soft and flexible films without curatives.
Films made from accelerator free 2GL have tensile strength equivalent to those produced with Cariflex IR. One drawback of the accelerator-free 2GL material, however, is poor solvent resistance that could cause films to dissolve in non-polar solvents, but Kraton said this can be overcome by formulating it with a small quantity of curatives.
It is too early to tell exactly what products the new Cariflex material may be suited for because the company is producing it just on a lab scale, though that may change in 2016, Henderson said.
“The product is designed for the dipped goods market, but given the mix of properties it has, I envision this will have potential outside of dipped goods,” he said. “Adhesives, foams, anything where latex is going. It's really a new generation of material. There is nothing like it on the market.”
There has been some testing on the new material, but Kraton is ready to “open up the doors and present it more widely,” according to Henderson. “It's still a development material, so there is no guarantee that it is going to be a commercial material. We believe enough in it now that we want to talk about it openly.”
The next step will be to produce the new generation material on a larger scale at its manufacturing facility in Brazil.
When that occurs, potential customers will be able to validate the technology on a larger scale, Henderson said, because thus far they have only been given small samples to test. “In order to commercialise the material, customers will need to receive volumes that are large enough so that they can run it on their manufacturing lines,” he said.