Rogan specializes in when to use LSR vs. other soft materials

Northbrook, Ill. — Molding technology has grown rapidly over the past few decades, expanding its capabilities in many markets. The integration of soft materials has changed the game for manufacturers and end users alike.

Many soft materials can bond to both other soft materials and hard materials. Their bonding abilities give designers an expanded freedom to create a different form of molded products.

One material revolutionizing the market is liquid silicone rubber because it expands capabilities, while decreasing the need for some secondary operation, according to an official at Rogan Corp., a molder of elastomers and thermoplastics.

Some of the most common uses of LSR are for handling and the operation of products, such as grips for everything from surgical instruments to hand-held electronic devices.

Utilizing this material can save manufacturers both time and money, but device makers must determine when LSR is preferable to other soft materials.

LSRs are typically used when a customer has biocompatible or temperature application requirements, said Jim Ritzema, Rogan's director of new product development. For silicones, he said Rogan only processes LSRs.

When manufacturers reach out to Rogan for help with product development, Ritzema said they first ask them if their application requires LSR because it's a material that gives manufacturers options. For example, it's a transparent material with the option to add color if needed.

“It keeps its properties at high and low temperatures,” Ritzema added.

LSR also is beneficial because it can be a medical grade that contains the following attributes: thermal stability; low compression set; excellent mold flow; minimal flash; autoclavable; and implantable.

When selecting a soft material, Ritzema advises manufacturers to work closely with molders and mold builders for optimal results because they have knowledge of how each material performs.

Some of the most common soft materials in the market today include: LSRs, RTVs (room temperature vulcanization silicone), HCR (high consistency silicone rubber), EPDM rubber (ethylene propylene diene monomer rubber) and PVC compounds.

Beyond material characteristics, manufacturers also should pay attention to both material price and the overall cost of a project. Adding new materials to production may require additional tooling costs. Consulting experts, from the molder to the material supplier, will help guide a manufacturer to select the best soft material for their needs.

Each soft material has its own attributes and is best suited for different applications.

When needing a biocompatible option, manufacturers should look at LSR, HCR or soft PVC, he said. For a material with chemical resistant properties, LSRs and RTVs are suitable. They both also have excellent mold flow properties with a low compression set.

For instance, LSRs are resistant to compression sets, keeping its shape where a thermoplastic elastomer eventually would form to the set. The LSR material does not compromise the seal because it will not compress over time.

Beyond its inherent capabilities, the major function of LSRs serve the medical market because it's a medical grade product, whereas other soft materials are not.

“We needed to expand our quality procedures so we could become ISO 13485 registered,” Ritzema said about Rogan's medical grade LSR.

However, if a manufacturer does not need a medical grade product, they should not pay for it, he said. Some of the characteristics to pay attention to when choosing the material is temperatures, tolerances and bonding requirements.

Ritzema said there is no benefit in choosing the most technically advanced product if a less expensive one meets the manufacturer's and end user's needs.

As stated, LSRs are most notable in the medical market.

“There are so many great attributes to LSR that lends itself to medical devices,” said Ritzema.

LSRs can provide a seal into medical device products or cases. LSRs also can be sterilized, so products previously were disposable do not need to be anymore, saving the end user money. Because of its sterilization capabilities, there are huge growth opportunities for LSRs in medical products, such as grips, handles and soft-touch buttons, he said.

Beyond medical devices, Ritzema said there are dental applications that also benefit from LSR. For instance, Rogan worked on a grip for a dental scraper that allows for comfortable use and for a way for the water to travel up.

Ritzema also said there are potential opportunities in the automotive and technology markets.

While automotive is typically an HCR market, he said, there are some applications that warrant LSR. The company has not yet embarked into automotive, but he knows there are suitable applications.

Additionally, while Rogen has not yet produced molds for the technology market, Ritzema has seen LSR used in cell phone and speaker covers because of its good UV protection and abrasion resistance.