Medical Adhesives, Sealants and Coatings

Selecting the right adhesive is a balancing act as engineers attempt to find products that meet conflicting end-use and manufacturability requirements. Medical device engineers also have to contend with a strict regulatory environment, and therefore often have the toughest time striking that balance. Master Bond’s latest white paper addresses five basic questions developed in-house to enable engineers to make a more educated choice when looking for the ideal medical adhesive for their application. Each question is a step towards choosing materials and adhesives that not only work together as a system, but also minimize trade-offs between performance and manufacturability.

EP42HT-2Med is commonly used in the manufacture and assembly surgical instruments, catheters, endoscopes, and other medical devices. As a USP Class VI system, EP42HT-2Med is well suited for use in prosthetics and implantable medical devices. In several research and development publications, scientists and engineers have singled out EP42HT-2Med for use in their applications. Following are brief descriptions of each application and its use of EP42HT-2Med.

Master Bond EP30-4Med is a two part epoxy system with a fast set up time that cures at room temperature, or even more rapidly with a bit of heat. This low viscosity system meets the requirements of ISO 10993-5 testing and is therefore considered to be non-cytotoxic. It can be used for bonding, sealing, and small encapsulation applications. It can also be utilized as a coating, especially when optical clarity is needed. EP30-4Med is designed to not only resist EtO sterilization, but also to withstand most detergents, disinfectants, bleaches and liquid sterilants. It is recommended for applications in medical device manufacturing for both disposable and reusable instruments. EP30-4Med has an easy to handle 2 to 1 mix ratio by weight and possesses a low viscosity of 1,000-3,000 cps for Part A and 20-100 cps for Part B. Mixing is effortless, especially with the use of a double barrel cartridge and static mixer. This epoxy has a refractive index of 1.55 and maintains good electrical insulation properties over time. Its volume resistivity is greater than 1015 ohm-cm. It forms strong bonds even in thin sections. EP30-4Med is a relatively fast setting system, and in some cases, depending upon the application and the substrates, fixtures often can be removed in 15-25 minutes. Full cure can be achieved in about 24 hours at 75°F. The ideal cure schedule is around 1-2 hours at 75°F followed by 1-2 hours at 135-150°F. Upon cure, it exhibits a Shore D hardness of 75 to 85. The product is available in 1/2 pint kits, pint kits, quart kits, and gallon kits. Specialty packaging is available in gun dispensers.

Structural adhesives now offer a new solution to replace traditional mechanical assembly. These kinds of adhesives are user-friendly and allow for the permanent assembly of similar and dissimilar substrates. Master Bond formulates a wide variety of versatile adhesive systems used to bond multiple types of plastics such as: ABS Nylon PEEK Phenolics Polycarbonate Polyester Polyetherimide Polyphenylsulfone Kevlar Acrylics Adhesives offer distinct advantages over mechanical fasteners and are utilized as an alternative in numerous manufacturing operations. Crucial benefits include: Uniform stress distribution Ideal for bonding dissimilar substrates Barely increase assembly weight Eliminate the need to drill holes Require no extra components – do not warrant different styles of nuts, bolts, etc. Liquid tight Gas proof Can join surfaces with diverse shapes, configuration and thicknesses No change in part geometry Create barrier against dust, dirt, sand, and other abrasive minerals High dynamic strength Durability and toughness Tolerance compensation – fill gaps or adhere surfaces with tight fits Aesthetically clean joints – invisible within assembly Shorten assembly time Easy, accurate dispensing manually or automatically Reduce waste Flexible design possibilities Protection from corrosion Ability to resist flex and vibration Minimal increase in weight of assembly Easy automation Minimal shrinkage upon cure Excellent cohesive strength Superior chemical and heat resistance Key Advantages of Structural Adhesive Bonding vs. Welding Structural epoxy adhesives, as an alternative to traditional welding techniques, eliminate the risk of electrical hazards and bring a host of significant advantages. These adhesives simplify processing, allowing for application on thinner substrates even in areas where access is limited. Unlike welding, structural adhesives enable bonding of diverse materials, including metals, most plastics, and composites, ensuring an even distribution of stress across the joint. This feature is particularly beneficial in reducing the concentration of stress points that can lead to material fatigue. Furthermore, adhesives provide dual functionality – they can bond and seal simultaneously, making them ideal for joining irregular or complex surfaces. This multifaceted capability, combined with their safety and versatility, positions structural adhesives as a superior choice in many engineering and manufacturing contexts.

Manufacturers of wearables and other medical devices can find suitable solutions among a number of medically safe adhesive systems, which are available in a wide variety of chemistries including epoxies, silicones and UV/LED-curable compounds. The use of biocompatible, non-toxic materials to avoid negative effects on skin and tissue, drives a fundamental need for safe adhesive, sealant, coating, and encapsulant compounds. Designed to address these concerns, a class of compounds combines proven biocompatibility and non-cytotoxic characteristics with performance properties required for the manufacture of medical devices and wearables intended for contact with the human body.