Two component, medical grade silicone for bonding and sealing

Key Features

  • Addition cured
  • Convenient processing
  • Excellent strength properties
  • Meets ISO 10993-5

Product Description

Master Bond MasterSil 323Med Black is a two component silicone for high performance bonding, sealing, and encapsulating. It does not require air when polymerizing and does not outgas while curing. It has a forgiving one to one mix ratio by weight. Although higher in viscosity, it is easily mixed and has good flow properties. It is a low exothermic material with a long open time of about 2-3 hours. It cures at ambient temperatures in 48-72 hours or in 2-4 hours at 135-165°F. The optimum cure is overnight at room temperature followed by 2-4 hours at 135-165°F. This silicone contains no solvents or diluents and has very low shrinkage upon curing.

MasterSil 323Med Black bonds well to a wide variety of substrates including metal, glass, plastics and ceramics, as well as to silicone rubber. It can withstand the most rigorous kinds of thermal shock and cycling without cracking or exerting stress on components. It can be used on disposable and reusable medical devices and it will resist various forms of sterilization including dry heat, UV and gamma radiation, EtO, glutaraldehyde, and other chemical sterilants. It has a Shore A hardness of 35 to 45. The combination of high viscosity but flowability prior to curing, and especially good bond strength after curing, is noteworthy. The service temperature range is from -65°F to +400°F. Other notable features are its opacity, especially in thinner sections, and its superior electrical insulation profile. MasterSil 323Med Black is a good candidate for disposable and reusable medical device manufacturing where a high viscosity silicone with a good strength profile is required.

Product Advantages

  • Addition cured, no by-products released during cure
  • Flowable, with long open time
  • Good bond strength
  • Low dielectric constant
  • Well suited for potting and encapsulation
  • Black in color, highly opaque

Industrial Certifications

ISO 10993-5 for Cytotoxicity

Meets EU Directive 2015/863



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MasterSil 323Med Black is available is various sizes and units to accommodate customer's needs.

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