Introduction
Selecting the right adhesive for your medical device is critical for both patient comfort and the profitability of your product. With various types of medical-grade adhesives available, it’s important to understand the unique properties of each to design devices that perform optimally and ensure patient satisfaction.
In this blog, we review the different medical-grade adhesives, highlighting the unique properties and primary use cases of each.
Understanding Adhesive Performance: Tack, Peel Adhesion & Shear Strength
Before discussing specific adhesives, it’s worth understanding how adhesive performance is typically measured:
- Tack: This measures the immediate stickiness when the adhesive first comes into contact with a surface. An adhesive with a high tack has a quick bond, which is crucial for applications that require immediate adhesion.
- Peel Adhesion (or Peel Resistance): This measures the strength of the bond when the adhesive is peeled away from the surface. A high peel adhesion is required in devices which need to remain securely attached over longer time periods.
- Shear Strength: This measures the adhesive’s ability to resist sliding or shifting under pressure. High shear strength is required for products where the adhesive will experience prolonged stress.
With this understanding of how adhesive performance is measured, let’s explore the various types of adhesives that can be used in medical device manufacturing.
1. Acrylic Adhesives
Acrylic adhesives have strong adhesion and excellent environmental resistance, making them a great choice in a range of medical applications including wound care products and wearable medical devices.
Characteristics:
- Tack: Moderate to high tack, ensuring a strong initial bond.
- Peel Adhesion: Very good, making it suitable for long-term use.
- Shear: High shear strength, making it durable under stress.
Suitable Body Parts:
- Chest and Back: Ideal for securing monitoring devices or large dressings due to the relatively flat and stable surface.
- Arms and Legs: Effective for attaching heavier devices like infusion pumps, where secure and prolonged adhesion is required.
Not Ideal For:
- Sensitive Areas: Such as the face, where the strong bond may cause discomfort during removal.
2. Silicone Adhesives
Silicone adhesives are softer and gentler, making them ideal for use on delicate skin. They are particularly suited for patients with fragile skin, such as the elderly or those with certain medical conditions.
Characteristics:
- Tack: Lower tack, allowing for easy repositioning without losing adhesion.
- Peel Adhesion: Moderate, suitable for applications requiring gentle but effective bonding.
- Shear: Adequate, with a focus on comfort rather than extreme durability.
Suitable Body Parts:
- Face: Ideal for attaching dressings or devices where the skin is delicate and sensitive.
- Neck and Shoulders: Suitable for applications where flexibility and comfort are prioritized, such as in prolonged monitoring.
Not Ideal For:
- High-Sweat Areas: Such as the feet and underarms where excessive moisture can weaken the adhesive bond.
- High-Friction Areas: Like the inner thighs or waistline, where constant movement may cause the adhesive to shift or lose its grip.
3. Natural Rubber
Natural rubber was once popular due to its high tensile strength and high tack, but its use in medical adhesives has declined due to its potential to cause latex allergies and its lower resistance to environmental factors.
Characteristics:
- Tack: High, offering a quick and strong bond.
- Peel Adhesion: Strong
- Shear: Good, though degradation under UV light is an issue.
Reasons for Declining Use:
- Latex Allergies: A significant number of patients experience allergic reactions to latex, leading to the decline in the use of natural rubber in medical settings.
- Environmental Degradation: Poor resistance to UV rays and solvents, making it less durable over time.
4. Synthetic Rubber
Synthetic rubber has emerged as a viable alternative to natural rubber due to its durability and versatility.
Characteristics:
- Tack: High tack, similar to natural rubber, with a secure initial bond.
- Peel Adhesion: Strong, suitable for demanding use cases.
- Shear: Very good, providing stability even under significant stress.
Suitable Body Parts:
- Feet: A notoriously difficult body part to design stick-to-skin devices for, the feet require adhesives that can withstand moisture and friction.
- Hands: Synthetic rubber adhesives offer the durability needed for applications on the hands, which are constantly moving and exposed to moisture.
Not Ideal For:
- Highly Flexible Areas: Such as the elbows, knees or wrists, where significant flexibility is required. Synthetic rubber does not conform to the contours of the body as effectively as silicone in these regions.
Conclusion
For any medical device, choosing the right adhesive from the outset is a critical decision that impacts both patient satisfaction and profitability. Each adhesive type has unique properties that make it better suited to specific body parts and uses cases.
Selecting the right adhesive for medical device manufacturing requires a deep understanding of medical-grade adhesives, their unique properties and their interactions with different body parts. At PolarSeal, we bring deep expertise in medical manufacturing. Our expert team can guide you through the complexities of adhesive performance, ensuring profitability and patient satisfaction.
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