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40 SMT Magazine • January 2015 Safety aspects 1233zd(E), being completely non-flamma- ble and having no flash point or upper or lower explosion limits, requires no specific explosion proofing like some other solvents. Toxicological test data for the solvent have also been com- pleted and the company Occupational Exposure Limit (OEL) of 800 ppm (8-hour time weighted average) has been assigned to 1233zd(E). Table 4 compares the occupational exposure limits of several solvents. All values quoted below are 8-hour time-weighted-average exposure con- centrations. Solubility with Oils We will now describe the cleaning perfor- mance of 1233zd(E). To start, we compared the solubility of various materials which may be considered as soils to be cleaned in 1233zd(E) in Table 4 and then the cleaning test results are shown in Table 5. The miscibility test was done where equal parts of solvent and oils are mixed together and visual observation was made to see if the soils and the 1233zd(E) remained in a single phase, indicating that the soils were completely dissolved in the solvent. In all cases the solvent looked clear and the mixtures are re- ported as miscible in Table 5. The purpose of the study is to test how well the solvent performs in dissolving various soils. Table 5 shows that 1233zd(E) has miscibil- ity properties similar to n-propyl bromide and AK-225 solvents which are good solvents and are currently used by a number of users in a wide variety of applications. All of these oils in Table 4 were found insoluble in pure HFCs and HFEs and require the addition of a co-solvent such as tr-1,2 dichloroethylene. So in summary 1233zd(E) has solvency characteristic as good as the current solvents for most common soils. Cleaning ability for Oils In the next step, we evaluated how good the solvent is at cleaning parts soiled with oils. In these tests, we soiled small 2" x 1" stainless steel coupons with various commercial oils used in the field. The coupons were immersed in boiling 1233zd(E) for 2 minutes and dried in the solvent vapors. This test was performed in small beakers with condenser coils near its lips which emulated conditions similar to a lab va- Table 4: Toxicity properties of selected solvents. (a) Company oel (occupational exposure limit) (b) Dupont Ael (Acceptable exposure limit) (c) 3M occupational aEl (d) asahi glass aEl (e) ACGih Threshold limit Value (TlV) (f) current acgIH TlV, a significantly lower value has been proposed and is under consideration Table 5: Soil dissolution in 1233zd(e). a In case of RMa solder flux, a blend of 1233zd(e) and methanol was used. an aLTErnaTIvE SOLvEnT WITH LOW GLOBaL WarMInG POTEnTIaL continues artiCle