Product Information Dow Corning 3-4207 Dielectric Gels Tough Gel FEATURES 2-part, translucent green, 1:1 mix ratio, fast ROOM TEMPERATURE cure tough gel with UV indicator, Fast room temperature cure conditional primerless adhesion and good flame resistance Two parts are blue and yellow and turn green when mixed Conditional primerless adhesion at room temperature Mechanical strength TYPICAL PROPERTIES UL 94 V-1 Flammability Rating Specification Writers: These values are not intended for use in preparing specifications. Please contact your local Dow Corning sales office or your Global Dow Corning UV indicator for inspection. Connection before writing specifications on this product. BENEFITS Fast RT cure, no ovens required Property Unit Value Indivdual parts are blue and yellow to Viscosity (Part A) cP 425 reduce potential for loading errors mPa-sec 425 When properly mixed the gel is green Pa-sec 0.4 Adhesion obtained at RT Toughened gel for additional Viscosity (Part B) cP 400 mechanical strength mPa-sec 400 Can be considered for uses requiring Pa-sec 0.4 added flame resistance UV indicator allows for automated Agency Listing - UL 94-V1 inspection Cure Time at 25C hrs 1.5 Gel Time 25C minutes 9.8 Heat Cure Time 50C minutes 10 Heat Cure Time 100C minutes 3 Durometer Shore 00 - 59 Unprimed Adhesion - 180 Degree ppi 3 Peel Strength N/cm2 2 Shelf Life at 25C months 12 packs prevents bubbling, maintains temperature range of -45 to 200C (- DESCRIPTION cleanliness and avoids gel 49 to 392F) for long periods of time. Under certain conditions in specific contamination. Gels can be However, at both the low- and high designs or applications, Dow dispensed manually or by using one temperature ends of the spectrum, Corning(R) 3-4207 Dielectric Tough of the available types of meter mix behavior of the materials and Gel may lose adhesion. Full equipment. Typically, the two performance in particular applications environmental exposure testing is components are of matched can become more complex and recommended. For applications that viscosities and are readily mixed with require additional considerations. For require gels with added strength, static or dynamic mixers, with low-temperature performance, there are tough or firm gel products. automated meter-mix normally used thermal cycling to conditions such as They can assist cost of ownership for high volume processes. For low- -55C (-67F) may be possible, but improvements due to their room volume applications, manual performance should be verified for termperature cure that requires no weighing and simple hand mixing your parts or assemblies. Factors that ovens though they can be heat may be appropriate. Inaccurate may influence performance are accelerated if desired. These materials proportioning or inadequate mixing configuration and stress sensitivity of have enhanced chemical adhesion and may cause localized or widespread components, cooling rates and hold cure slightly harder than standard problems affecting the gel properties times, and prior temperature history. gels, but may have limited or cure characteristics. If possible, the At the high-temperature end, the applicability depending on processing potential for entrapment and durability of the cured silicone conditions, device design, end-use incorporation of gas (typically air) elastomer is time and temperature environment and other conditions. should be considered during design of dependent. As expected, the higher Gels are a special class of the part and selection of a process to the temperature, the shorter the time encapsulants that cure to an extremely mix and dispense the gel. This is the material will remain useable. soft material. Gels cure in place to especially important with higher- form cushioning, self-healing, viscosity and faster-curing gels. resilient materials. Cured gels retain COMPATIBILITY Degassing at >28 inches (10-20 mm) much of the stress relief and self- Certain materials, chemicals, curing Hg vacuum may be necessary to healing qualities of a liquid while agents and plasticizers can inhibit the ensure a void-free, protective layer. providing the dimensional stability of cure of addition cure adhesives. Most an elastomer which is increasingly notable of these include: Organotin needed for delicate components. Gels POT LIFE AND CURE and other organometallic compounds, have been used to isolate circuits Silicone rubber containing organotin RATE from the harmful effects of moisture catalyst, Sulfur, polysulfides, Working time (or pot life) is the time and other contaminants and provide polysulfones or other sulfur required for the initial mixed electrical insulation for high voltages. containing materials, unsaturated viscosity to double at room Another use is providing stress relief hydrocarbon plasitcizers, and some temperature (RT). The cure reaction to protect circuits and solder flux residues. If a substrate or begins when Parts A and B are interconnections from thermal and material is questionable with respect mixed. As the cure progresses, mechanical stresses. Gels are usually to potentially causing inhibition of viscosity increases until the material applied in thick layers to totally cure, it is recommended that a small becomes a soft gel. Cure conditions encapsulate higher architectures. scale compatibility test be run to are shown in the typical properties More recently, gels have found ascertain suitability in a given table. Cure is defined as the time application in optoelectronics due to application. The presence of liquid or required for a specific gel to reach their stress relieving capability and uncured product at the interface 90% of its final properties. Gels will high refractive index, as well as the between the questionable substrate reach a no-flow state prior to full stability of these properties over time. and the cured gel indicates cure. Addition-cure silicone gels may incompatibility and inhibition of cure. be RT and heat cure or exclusively MIXING AND DE-AIRING heat cure. Adding heat accelerates the Some gels are supplied in bladder cure reaction. Additional time should REPAIRABILITY packs that avoid direct air contact be allowed for heating the part to near In the manufacture of electronic with the liquid gel components, oven temperature. Cure schedules devices, salvage or rework of allowing use of air pressure over the should be verified in each new damaged or defective units is often pack in a pressure pot for dispensing. application. required. Removal of Dow Corning Do not apply air pressure directly to dielectric gels to allow necessary the liquid gel surface (without the repairs can be assisted by using Dow USEFUL TEMPERATURE bladder pack) as the gel can become Corning OS Fluids. Additional RANGES supersaturated with air and bubbling information regarding these products For most uses, silicone elastomers can occur when the material is is available from Dow Corning. should be operational over a dispensed and cured. Use of bladder