Novagard

Overview of Cure Chemistries

Moisture Cure

Novagard manufactures one component and two component moisture cure materials. Rather than using heat to cure, these materials react with moisture to initiate the crosslinking process.This produces a small amount of byproduct. For electronics applications, engineers typically prefer an alkoxy moisture cure, which produces only non-corrosive methanol as its byproduct. Care must be taken when selecting oxime silicones as their byproducts can be corrosive to copper and yellow metals in enclosed environments. 

Single component materials arrive from Novagard completely mixed and ready to use. The curing of single component materials is limited by the rate at which the material can absorb moisture from the atmosphere, typically hours to days. Single component silicones are valued for their ease of use, strong adhesion, and shelf stability.

Novagard two component moisture cure materials are separate components (Part A and Part B) that must be mixed prior to use. The moisture required to drive the crosslinking process is contained within one of the components, which allows these products to cure rapidly (minutes to hours), speeding production. The mix ratio of two component systems may be fixed or variable, depending on the formulation and your manufacturing requirements. These products are typically meter-mixed for precise control.

Addition Cure

Addition cure materials arrive from Novagard as separate components (Part A and Part B) that must be mixed in a specific ratio prior to use. Everything necessary to crosslink these materials is contained within either Part A or Part B. Once the two components are mixed, the platinum catalyzed reaction occurs automatically – no added moisture or energy is necessary to complete the reaction (although the cure can often be accelerated with heat).

Two component addition cure materials crosslink very uniformly and predictably, do not absorb any constituent from the atmosphere, nor release any byproduct, eliminating shrinkage and the associated stresses. Addition cure materials typically have very limited adhesion, further reducing stress on components.

UV Cure

Novagard UV Cure materials are premixed and arrive ready to use. Once dispensed, these materials require energy to drive the crosslinking process. This energy comes from UV light, traditionally from a broad-spectrum mercury lamp, but more recently from a narrow spectrum LED lamp. Novagard UV cure materials can be cured by using either a broad-spectrum UV system or a 365nm LED UV system. Once exposed to sufficient UV energy, the crosslinking process occurs very rapidly — often as quickly as 3 - 5 seconds (versus 40 – 50 seconds for competitors).