Military Certifications

Master Bond EP17HTS-DA is a new one component, no mix, die attach epoxy that is electrically conductive and withstands high temperatures. It is a silver filled system. Typically, glass transition temperature (Tg) declines with the addition of a filler like silver. However, with this specialty formulation, a high Tg of 140-150°C is maintained and it passes MIL-STD-883J thermal stability requirements at 200°C. Its strength profile is also notably robust with a die shear strength of 35-40 kg-f at room temperature. EP17HTS-DA meets NASA low outgassing specifications and its service temperature extends from -80°F to 550°F. It has a low volume resistivity of less than 0.005 ohm-cm and also performs well as a heat conductor. EP17HTS-DA is a thixotropic paste and can be easily dispensed manually or via automated dispensing systems. This compound is not premixed and frozen and has an unlimited working life at room temperature. It requires a heat cure of 300°F for 2 to 3 hours, followed by post curing at 350°F for 1 to 2 hours. This product bonds well to many substrates including metals, ceramics and plastics. It is recommended for applications where low volume resistivity and high temperature resistance is required. EP17HTS-DA is available for use in syringes and glass jars, in sizes ranging from 20 grams to several pounds.

On the most basic level fungal build up on epoxy resin systems weaken the core performance properties of the adhesive itself resulting in adhesive failure. The fungus work to break down the resin into smaller particles as a nutritional source to obtain carbon. Among other things, this degradation causes the adhesive, sealant or encapsulant to lose its ability to protect against chemical and moisture exposure. Below is an outline of the harmful effects of fungus on epoxies:Material DeteriorationThe physical properties of the adhesive are compromised due to the molecular degradation caused by the fungus.Electrical FailuresAt times the fungal growth can create an electrical bridge over insulating materials producing electrical failures.Restricted Movement of Small PartsThe fungus can fuse together small mechanical parts restricting their movement.Moisture to Non-Wetting SurfacesFungal communities introduce moisture into their living environments which can cause further damage to bonded parts.How do fungus resistant adhesives work?Safeguarding aerospace/military equipment and electronic devices from the harmful effects of these organisms is of prime importance in order to ensure optimal adhesive performance. Fungus resistant adhesives, sealants and encapsulants maintain their physical, mechanical, electrical and optical properties even upon exposure to moisture or warm temperatures. They are engineered to be non-nutrient so that they avoid any degradation including defending against marring of optical components, thwarting the blockage of moving parts, impeding moisture permeation in electronic parts even – upon conditions that are conducive to fungal growth.How do you test an adhesive’s fungus resistance?One of the most robust ways of testing adhesives for fungus resistance is with the MIL-STD-810G with Change 1, Method 508.7 standard. This stringent military standard was developed by the U.S. Department of Defense. It is used to determine the extent to which a product will support fungal growth, how that growth can affect the performance of the material, and what specific species have grown. The epoxy samples are inoculated with a spore suspension consisting of the following organisms:Aspergillus flavusAspergillus versicolorPenicillium funiculosumChaetomium globosumAspergillus brasiliensis (formerly known as A.niger)How is the MIL-STD-810G standard test performed?MIL-STD-810G with Change 1, Method 508.7 was employed on many Master Bond products to determine their fungus resistance. Products were rated for amount of growth with 0 being devoid of microbial growth and 4 representing massive growth.Fungus Rating GuidelineGrowth AmountRatingObservationNone0Substrate is devoid of microbial growthTrace1Substrate is devoid of microbial growth.Light2Intermittent infestations or loosely spread microbial colonies on substrate surface.Medium3Substantial amount of microbial growth. Substrate may exhibit visible structural change.Heavy4Massive microbial growth.Specimens were preconditioned at 30°C and 90% minimum relative humidity within the test chamber. They were then sprayed with prepared spore suspension. The objective was to assess the select adhesive system to ascertain if it would support fungus growth, whether it can function after exposure and identify the species (if growth occurs). Samples were tested for 28 days and exhibited no signs of fungal growth. Specified temperature for test and moisture level was most conducive for spore germination and growth. Sample specimens were compared with a control sample. Below are a handful of the tested epoxies including their test results:Test Results of Master Bond Fungus Resistant SystemsPart NumberProduct InformationVisual Results After 28 DaysMasterSil 151AOFlexible silicone casting, potting and sealing system with thermal conductivity of 0.35-.0.54 W/(m•K)0 – NoneEP36ANB-stage epoxy potting & bonding compound with outstanding toughness and resistance up to 500°F0 – NoneEP39MAOHTLow viscosity epoxy with superior dielectric properties resists thermal cycling and mechanical shock0 – NoneEP3RR-80One part epoxy cures at 80°C or higher features low exotherm upon cure0 – NoneEP30LTE-LOTwo part epoxy with extra low coefficient of thermal expansion and unmatched dimensional stability0 – NoneEP37-3FLFAOFlexible, low viscosity, thermally conductive epoxy meets NASA low outgassing specifications0 – NoneControl SpecimenConsists of sterile potato dextrose agar and unbleached, plain weave, 100% cotton cloth strips4 - Heavy growth (60% to complete coverage)Learn more about our systems meeting MIL-STD-810G specifications

One component, heat cure system for bonding, sealing. High strength product. Service operating temperature range from 4K to +500°F (260°C). Resists aggressive thermal cycling and shock. Substantial thermal conductivity of 9-10 BTU in/ft2 hr °F. Smooth thixotropic paste. NASA low outgassing approved. Meets MIL-STD-883J Section 3.5.2 for thermal stability. Withstands 1,000 hours 85°C/85% RH.

Some epoxy compounds successfully meet thermal stability testing standard ASTM D3850-12 per MIL-STD-883J Section 3.5.2 & 3.8.5 for military applications, however these systems can also be used across many other industries where thermal stability is an important requirement. The thermal stability test is not just an aggressive check for the high temperature serviceability of such compounds, but it also is an excellent starting point for using such compounds in high temperature applications. Other considerations to keep in mind are the continuous, as well as the maximum service temperature range, thermal cycle ramp speeds, and other thermally induced stresses in the application. Some common non-military applications that benefit from compounds that pass MIL-STD-883J include downhole oil equipment, lasers, satellite systems, electronics, power tools, as well as various automotive applications.MIL-STD-883J testing for polymers involves thermal stability analysis, by running a Thermogravimetric Analysis (TGA). The thermal stability is determined by heating the specimens from room temperature to 200°C at a heating rate of 10°C/minute in a nitrogen atmosphere. The thermal stability of the cured material is determined by the weight loss at 200°C. For the polymer compound to pass the test, the weight loss must be less than or equal to 1.0 percent of the cured material weight prior to the exposure to the temperatures.These thermally stable adhesive systems offer many other advantages especially over traditional fastening techniques, such as improved load bearing capacity, stress distribution, resistance to cyclical fatigues, protection against chemicals, and light weighting, to name a few. Designers and engineers must be mindful of the processing considerations such as surface preparation, and cure schedules while selecting the right product. It is best to consult with the supplier’s recommendations while choosing the adhesive, sealant, coating, or potting compound, and also for the best processes to use.To read more about Master Bond adhesives that passed MIL-STD-883J testing please click here.