{"id":49685,"date":"2014-04-11T13:14:05","date_gmt":"2014-04-11T13:14:05","guid":{"rendered":"http:\/\/sentryair.com\/blog\/?p=49685"},"modified":"2020-07-02T20:06:23","modified_gmt":"2020-07-02T20:06:23","slug":"fume-extraction-for-electrical-potting-and-encapsulating-compounds","status":"publish","type":"post","link":"https:\/\/www.sentryair.com\/blog\/product-review\/fume-hoods\/ductless-fume-hood\/fume-extraction-for-electrical-potting-and-encapsulating-compounds\/","title":{"rendered":"Fume Extraction for Electrical Potting and Encapsulating Compounds"},"content":{"rendered":"

\"electric-wires-720\"<\/a>Electrical components including PCBs, wires, and other assemblies require a form of “seal” to protect them from environmental exposures that could result in electrical shorts, sparks or complete electrical failure.<\/p>\n

There are a variety of products and techniques on the market used to create these seals. For today’s discussion we will focus on the product Hysol\u00ae<\/sup> US4028<\/i>. Hysol\u00ae<\/sup> is a product line of Henkel.<\/p>\n

Hysol\u00ae<\/sup> US4028 <\/b>is a flexible polyurethane elastomer formulated for general potting and encapsulation, particularly used for electrical components.<\/p>\n

\"electrical<\/a>Potting is the technique used to surround, coat or envelop an electronic component in a liquid resin to protect it from environmental conditions.<\/p>\n

Similarly, encapsulation is the technique in which an electrical component is surrounded, coated or enveloped in a solid resin to protect it from environmental conditions.<\/p>\n

The compounds used in Hysol\u00ae<\/sup> US4028 provide mechanical reinforcement to housed assemblies, fill large voids, and protect components from exposure to chemicals, moisture, mechanical shock and vibration.<\/p>\n

Its many positive properties include low viscosity, low moisture resistivity, and excellent tear and abrasion resistance.<\/p>\n

When working with this product it is important to note the respiratory hazards present and implement adequate engineering safety controls.<\/p>\n

A + B = Hazardous Fumes<\/strong><\/p>\n

Hysol\u00ae<\/sup> US4028<\/a> is made up of two polyurethane components, Part A – Resin<\/a> and Part B – Hardener<\/a>. Each component must be pre-mixed before they are mixed together. The mixed ratio by volume is 5.4 : 1.0 (Part A : Part B).<\/p>\n

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Part A Hazardous Components & Exposure Limits <\/b><\/p>\n<\/td>\n<\/tr>\n

Polyurethane Resin<\/td>\nNo established exposure limits<\/td>\n<\/tr>\n
Dicyclohexylmethane-4<\/td>\nNIOSH REL: 0.01 ppm (0.11 mg\/m3<\/sup>)ACGIH TLV: 0.005 ppm TWA<\/td>\n<\/tr>\n
\n

Part B Hazardous Components & Exposure Limits<\/b><\/p>\n<\/td>\n<\/tr>\n

Butyl benzyl phthalate<\/td>\nNo established exposure limits<\/td>\n<\/tr>\n
m-Phenylenediamine<\/td>\nACGIH TLV: 0.1 mg\/m3 <\/sup>TWA<\/td>\n<\/tr>\n
N-Methyl-2- pyrrolidone<\/td>\nAIHA WEEL: 10 ppm TWA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\"Acronyms-01\"<\/p>\n

Once both parts are combined, the mixture must cure. Cure conditions depend on time and temperature. The below cure schedule is from the product’s technical data sheet.<\/p>\n

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Typical Curing Schedule<\/b><\/p>\n<\/td>\n<\/tr>\n

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Time<\/b><\/p>\n<\/td>\n

\n

Temperature<\/b><\/p>\n<\/td>\n

\n

Notes<\/b><\/p>\n<\/td>\n<\/tr>\n

21 hours<\/td>\n77\u00b0 F<\/td>\nPlus 2.4 hours at 165\u00b0 F – 185\u00b0 F<\/td>\n<\/tr>\n
16 hours<\/td>\n156\u00b0 F – 163\u00b0 F<\/td>\n <\/td>\n<\/tr>\n
8 hours<\/td>\n165\u00b0 F – 185\u00b0 F<\/td>\n <\/td>\n<\/tr>\n
7 days<\/td>\n77\u00b0 F<\/td>\nFor full properties<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\"Dust_fumes_inhalation\"<\/a>Most of these cure times require an elevated temperature which means a heating element must be used.<\/p>\n

When heated, the mixture can form into vapor which then emits volatile organic compounds (VOCs) into the air.<\/p>\n

The material safety data sheets (MSDS) for both Part A and B contain numerous cautions about inhaling these compounds. Here is a snapshot of the cautions listed.<\/p>\n

Part A<\/span><\/p>\n