Staying Connected - November 2012

Thermoplastic Polyurethanes Used in Medical Cable Assemblies

Rugged medical connector with
TPU overmolded components

A thermoplastic resin, such as polyurethane, is a material that softens when heated and hardens again when cooled.  This allows the material to be used in molding and extrusion, two processes used in the manufacture of medical cables.  Thermoplastic polyurethane resins are commonly referred to as “TPU.”

Most medical cable assemblies have one or more molded components, such as a strain relief or yoke.  These components are formed by injecting nearly liquefied mold material under high pressure into a mold cavity where the components to be encapsulated are held in place.  Several resins are commonly used for molding medical cable components including thermoplastic elastomers such as Santoprene®, polypropylene, PVC and polyurethane.  Each of these materials has advantages and disadvantages which must be weighed when selecting the most appropriate material for the application.

Thermoplastic urethanes can be
used to mold thin-wall sections

Mold Characteristics of TPU

The characteristics of thermoplastic polyurethane make it a good choice for insert molding where thin wall sections may be required such as in shooting the outer mold of a small part.  Polyurethane resins can be nearly liquefied when heated which allows for the mold cavity to be completely filled correctly forming intricate detail

The Chemistry of TPU Resins

Thermoplastic polyurethanes achieve their unique properties due to the chemical reactions that form the material.  Briefly, TPU resins are formed by the reaction of combining a polyol (a long-chain diol), a chain-extender (a short-chain diol) and di-isocyanate.  The di-isocyanate provides the chemical bond between the diols.
By varying the structure and molecular weight of the three compounds, resins with a variety of different properties, including chemical resistance and hardness are possible.

TPU resins are referred to as block-copolymers.  They consist of softer and rather long linear polymeric chains in block-structures. These alternate with shorter, hard segments and are joined by covalent links to form the block-copolymer. 
Polyurethane resins contain physical crosslinks, rather than chemical crosslinks.  The physical crosslinks become ineffective when heated and allow the material to soften, liquefy and flow.  It is this property of the resin which allows it to be used for injection molding and extrusion.  When cooled, the physical crosslinks re-engage and the material becomes hard.

Performance Characteristics of TPU Resins

While each thermoplastic polyurethane resin has different characteristics, common to most are the following:

  • Good abrasion resistance
  • Good elasticity
  • Good resistance to common cleaning solutions
  • Excellent low-temperature impact strength
  • Good flexibility over a wide temperature range
  • Good tactile “feel” properties
  • Good adhesive properties
  • Easily colored

TPU resins do not stand up to
sterilization by autoclave

TPU resins are not suitable when sterilization by autoclave is required.

TPU Resins Used by Affinity

A variety of polyurethane resins are used by Affinity.  All are Ether based which means that they do not break-down when exposed to water and are more resistant to microbial growth, which is often a consideration for medical applications.

Lubrizol Pellethane® – A very durable material with high tear and tensile strength, high abrasion resistance and very good adhesion to many substrates.  Pellethane is available in a wide variety of durometers (53D to 90A) and is available in medical grades.

Lubrizon Estane® – Estane is similar to Pellethane but with more available grades and durometers.  Estane is not available in medical grades.

Lubrizol Tecothane® – an TPU resin that is available in durometers as low as 42A.  Tecothane has good adhesive properties and is available in medical grades.

Bayer Desmopan® – Desmopan high tear strength, easier to mold, good adhesion to many substrates and is available in medical grades

GLS Versollan® – A TPU alloy used for thin wall applications with excellent adhesion to polycarbonates, ABS, and PC/ABS substrates. Versollan has low tear strength but provides soft feel and grip and good resistance to chemicals. Versollan is available in low (soft) durometers and medical grades.

Huntsman Irogran® –  A TPU resin that Affinity often specifies as jacket material for raw cable.  Irogran offers excellent abrasion resistance, tensile strength and cut resistance.  These characteristics, coupled with the availability of low durometer resins make this material a good choice for suitable cable jacketing medical cable.


The Affinity engineering team has expertise and experience recommending resins to be used for overmolding and jacketing raw cable.  If you would like to discuss thermoplastic urethane resins, or any other aspect of using these materials in the manufacture of medical cable assemblies contact us through our website, call us at +1 949-477-9495 or via email to

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Molex Affinity Acquisition Update

Molex Incorporated acquired Affinity Medical on October 10, 2012.  Since that time, Affinity OEM partners have likely not noticed any differences in working with Affinity.  “The same Affinity team is here, in place, with the desire and commitment to serve you as we have for the past 15 years,” said General Manager Bob Frank.

Affinity General Manager,
Bob Frank

“Molex is adding to Affinity’s capabilities, not taking anything away.  We are actively hiring to keep up with increased demand in manufacturing, engineering and quality.  We’re also strengthening our Customer Care group,” commented Bob.

As a reminder, while Affinity’s branding has changed to Affinity Medical a Molex Company, the company’s legal name remains Affinity Medical Technologies, LLC.
Medica Wrap-up

The Affinity team traveled again to Dusseldorf Germany to exhibit at the world’s largest medical exhibition, Medica.

The Affinity team at Medica

During the four days of the show, the Affinity team met with over forty OEM partners and prospective customers from around the world.  “We are able to meet with more people at Medica than we could traveling around the world for weeks,” said Affinity General Manager, Bob Frank.

“Medica is very different from most of the medical exhibitions in the U.S.,” said Bob.  At Medica it is customary to invite guests to your stand, sit down with them and perhaps share a coffee, soft drink or small snack.  And, while business is discussed, Medica is very much about building and renewing relationships.  This fits well with the way we operate”

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Meet Jim Itkin – Affinity OEM Sales Manager

Jim Itkin – Affinity OEM
Sales Manager

Jim Itkin joined Affinity Medical in October 2010 as OEM Sales Manager.  Jim came to Affinity from Covidien where he was responsible for OEM sales both domestic and internationally for the company’s core products.

Jim has spent his entire career in the medical industry beginning twenty years ago selling disposable medical products to acute care hospitals for Jason International.  Jim’s success led to a promotion as Electrode Product Manger which required him to relocate to Southern California.  Jim successfully led the growth of ElectroTrace™ brand of ECG electrodes which resulted in his promotion to National Sales Manager for Jason-Kendall LTP, which became part of Covidien.

Jim spends time in manu-
facturing during a plant visit

Jim moved from hospital sales into OEM sales in 2001 which also required him to move from Southern California to Massachusetts, where the company’s headquarters were located.  In the past 11 years, Jim has developed excellent relationships with his OEM customers by being honest, responsive and by providing timely and accurate information.

 “When we decided to hire an OEM Sales Manager, I knew who I wanted right away,” said Affinity Business Development Manager, Hank Mancini.  “I worked with Jim for more than ten years and knew that he was a quality individual.  He takes a very customer-oriented approach to business and that’s what we wanted at Affinity.  Jim has a tremendous amount of energy has been instrumental in Affinity’s growth the past two years.”

 “While he has primarily been on the sales side of the business, Jim has a great technical background,” said Hank.  He knows what it takes to design and manufacture medical products.  He also understands quality systems, having participated in many customer audits.  He understands Affinity’s capabilities and that helps him understand what projects fit Affinity and which ones don’t.”

Jim & former Affinity President, Mary Phillipp

After Affinity was acquired by Molex in October, Jim was asked about his feelings regarding the merger.  “What excites me most about the acquisition is that Molex and Affinity share the same cultural values: superior quality, dedication to customer service and the understanding and appreciation of long-term relationships. Molex has a reputation for excellence and I am proud to let our OEM customers know that we are now part of Molex.”

Jim earned his bachelor’s degree from Florida State University and his MBA from Bentley University, one of the nation’s leading business schools.

Jim’s met his wife Barbara when they were in high school and they have been together nearly thirty years.  Barbara is now a high-school teacher and their daughter Michelle is in elementary school.  Jim and his family live in Western Massachusetts.

Besides working, Jim is a real car enthusiast with encyclopedic knowledge of brands, models, performance specs and even prices.  Jim realized one of his dreams a few years when he purchased a bright yellow Corvette.  He only drives his “Vette” for pleasure and only when the weather is good.  For vacations, Jim and his family enjoy traveling to warm beach destinations, especially St. John, or taking ocean cruises

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Announcements, Information and Trivia

Orville & Wilber’s “Flying Machine”
was patented in May 1906
– image source Wikipedia

Above the Arctic Circle, the sun
barely rises above the horizon
shortly before the Winter Solstice

Winter Facts

Hanukkah - Hanukkah 2012 begins at sunset on Saturday, December 8, and ends at nightfall on Monday, December 17

Winter Solstice – The December solstice, also known as Winter Solstice, occurs when the North Pole is tilted 23.5 degrees away from the sun.  When this occurs, all places above latitude 66.5 degrees north will be in darkness.  The Winter Solstice will occur December 21, 2012.

Saturnalia - In Ancient Rome the winter solstice festival of Saturnalia began on December 17 and lasted for seven days. It was held to honor the “father of the gods,” Saturn.  Saturnalia was characterized by the suspension of discipline and reversal of the usual order. Slaves were served by their masters, wars were suspended and quarrels were forgotten.  It became common to wear disguises during Saturnalia.

Kwanzaa - often spelled “Kwanza” in African countries, means “first” in the Swahili language and signifies the “fruits of the harvest.” Kwanzaa begins on December 26 and continues through January 1st.  Kwanzaa is a time of reflection and a time to reconnect with the community and family.

An Inch of Rain – Ten inches of snow typically melts to about an inch of rain.

December Holidays

Affinity will be closed Monday December 24th and Tuesday December 25th in observance of Christmas.

Affinity will be open on Monday, December 31st and closed on Tuesday January 1, 2013 in observance of New Year’s Day.