ANAHEIM, Calif.—Shin-Etsu Silicones of America Inc. introduced its low Dn LIMS product line at MD&M West 2015 at the Anaheim Convention Center Feb. 10-12.
The KEG2003H low Dn LIMS product line is formulated and manufactured to significantly reduce the level of low molecular weight siloxane (Dn) volatile content to allow molders the opportunity to eliminate costly post-curing from their manufacturing process, Shin-Etsu said.
KEG2003H is available in hardnesses from 30-70 Shore A and has physical properties similar to Shin-Etsu's KEG2000 series.
“A lot of our molders are forced or choose to post-cure their parts after they have been molded,” said Eric Bishop, North America marketing manager for Shin-Etsu.
In many cases, the purpose of post-curing is to drive off any type of residual volatiles that could be in the silicone rubber, he added.
These silicone molders are forced to post-cure their molded articles for up to four hours at 400°F in order to meet stringent regulatory and customer requirements for low volatile content.
“There are a lot of reasons in different industries that you would want to or need to post-cure,” Bishop said.
The KEG2003H product line is most directly targeted at baby care and drinking equipment, he said. But it also is applicable in automotive applications where customers might not want to post-cure to drive off volatiles so they do not interfere with electronic equipment, or in the health care and medical device industries as well. It basically affects industries where leachables cannot be tolerated.
With this product, Shin-Etsu has manufactured it so “essentially we are stripping out some of those volatiles in the plant so that the molder is not left with the responsibility or the obligation to have to do that,” Bishop said.
And the benefit to the molder is that it “really streamlines their whole manufacturing process and makes it much more efficient.”
These parts in a barrel, he added, have to be somewhat laid out on racks so that air can get to them. “Much like if you were baking something,” Bishop said. “You can't just throw in a glob of dough and expect it to bake.”
Post-curing is a costly manufacturing process. It takes manual handling, so an opportunity exists for contamination. Additionally, there is a lot of air flow in the machine, so there is a contamination risk factor during the process.
In the medical industry, most devices have to pass either USG Class 6 or ISO 10993, Bishop said. Those standards basically are looking for contaminates or anything in the product that would either cause the body to react adversely or that could be toxic.
“Any residuals are undesirable, and for that reason, many of our medical customers will post-cure the article and just to be on the safe side,” he said
The more residuals a company can drive off in post-cure oven, the less that could be around to interact later.
Shin-Etsu's aim is if it can reduce those volatiles from the beginning at its plant, then the benefit to the molder is they don't have to do the post-cure, Bishop said.
Most notably, manufacturers of children's drinking equipment must comply with the European Standard, EN14350, which specifies a maximum weight-loss (volatile content) of 0.5 percent, Shin-Etsu said. Historically, this low level only can be achieved with lengthy post-curing in an industrial convection oven. However, with the KEG2003H product line, that has changed. Shin-Etsu said tests indicate that the average weight loss measured according to the EN14350 standard protocol is 0.3 percent.
“My colleagues in Europe were first to really bring this to the marketplace,” Bishop said, because their customers all need it for a variety of reasons. “They've been the ones who have been introducing it initially, and they've got some customers who have already qualified it on some applications.”
Since the European counterparts have worked through some of the launching logistics, Bishop said the company now feels comfortable launching in North America as well.
Shin-Etsu launched the KEG2003H at the MD&M Show not only because it is one of the largest shows the company exhibits, but also because it sees a fit for medical device customers.
Many fabricators who mold for medical also mold for other industries as well, he added. The company has started sending out samples based on the inquiries from the show.