Silicone Adhesives – Challenges and Solutions

By Sangita Viswanathan
November 12, 2014


• Categories: 04-Product Design & Development, RC - Device Design & Manufacturing

Kris Godbey, Senior Technical Support Engineer for 3M Medical Specialties, recently spoke about material selection and advanced assembly for body-worn devices. In a presentation, Godbey described by stick to skin is challenging, and what were some factors that could make device adhesion difficult. We present some excerpts:

Customers have basic goals and expectation of silicone adhesives that it can hold the device or dressing in place while the device performs the intended function, until the time the clinical objective in achieved. The requirements are that:

• There is good initial and long term adhesion;
• The adhesive is easy to use and apply; and importantly,
• It’s easy to remove with minimal skin trauma.

Human skin is a notoriously difficult surface for anything to stick because of its low surface energy. Other factors affecting good skin adhesion include:

• Dwell time or the length of time that the adhesive is applied to the skin- longer the adhesive, lower the adhesion;
• Cleanliness of the skin, which is affected by dead skin cells, surface oils and moisture; and
• Roughness of the surface, which is affected by hair and hair regrowth and age factors – for instance, older skin is thin and fragile and more exposed to weather and sun and often dehydrated.
• A typical person also generates an entire new skin surface in two to five weeks.

Traditional stick-to-skin adhesives can result in hair pulling at removal, and skin stretches resulting in mechanical trauma and possible skin stripping. Thus, medical adhesive tapes must balance between adequate adhesion levels for majority of users (in the middle of bell curve) and those at the ends of the bell curve. For instance, if the adhesion is too low, they will not stick well for the time needed; if the adhesion is too high, it could cause skin trauma, especially in people with delicate skin.

What are risk factors for skin stripping? This is common is very old or very young patients (geriatric or pediatric patients); those with fragile or sensitive skin; those with long-term corticosteroid use; and those who have had skin changes because of chemo or radiation therapy.

Advantages of silicone adhesives

Silicone adhesives balance adequate adhesion levels with wide range of skin types. It has low negative impact to skin surface; it doesn’t stick to hair surfaces, so rarely pulls out hair during removal, and has low affinity to attract dead cells, which helps in minimizing infection.

Below are examples of some suitable devices for silicone adhesive tape usage:

Protection:

• Pressure sore cushions
• Prosthetic sleeves
• Skin protective taping
• Mask seal

Treatments:

• Wound dressings & bandages
• Draining devices
• Topical dressings

Rehab:

• Skin replacement covering
• Prosthetics
• Ostomy devices
• Tracheotomy tube securement

Retail segment:

• Nipple cover
• Temporary tattoos
• Eye patches

Monitoring & Testing:

• Electrodes / cardio-monitoring
• Mammography markers

Anything neonatal and geriatric:

• Cannulas
• Tube securement
• Hydrocolloid replacement.