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Trial Purpose:
Determine a safer alternative for cleaning applications to remove solvent-based coatings using Hansen Solubility Parameters in Practice (HSPiP) off stainless steel surfaces.
Date Run:
07/08/2019Experiment Procedure:
Initial weights for the stainless-steel coupons were recorded before applying the supplied coating to the bottom one third of the coupons using a swab. The coupons were covered and aged for one week. After aging, the contaminated weights were recorded before immersing each coupon in a beaker containing 50-60ml of a solvent for one hour. Final weights were recorded after the coupons were removed and wiped with a Wypall.
A rating system of zero to five was developed to the efficiency of the solvent in its ability to remove the coating from the substrate. If little to no soil was removed from the coupon, the solvent would receive a zero (0), and if most or all soil was removed from the coupon, the solvent would receive a five (5). The scoring was established based on the percent weight removal of the coating. The ratings were entered into the HSPiP software, and a sphere was generated from that data.
The HSPiP sphere has size parameters that associate with its solubility. These parameters were entered into the Database of Safe Solvents (DOSS [1]), with a tolerance of +/- one value to create a range for identifying a safer solvent. DOSS provided a list of solvents that were within the values given and exported into the HSPiP optimizer option. The optimization evaluation found solvents and solvent blends that were closest to the parameters of the coating HSPiP sphere.
HSPiP Chemicals:
(1) Toluene (2) Dimethyl Carbonate, (3) Xylenes, (4) Benzyl Alcohol, (5) Ethylene Glycol, (6) Methyl Acetate, (7) Undecane, (8) Ethyl Lactate, (9) Acetone, (10) Ethyl Acetate, (11) Methanol, (12) Ethanol, (13) 1,3-Dioxolane, (14) Diethyl Carbonate, (15) 1-Propanol, (16) Iso-Propanol, (17) Propylene Carbonate, (18) Thiophene, (19) 1-Methoxy-2-Propanol, (20) Dimethyl Sulfoxide, (21) 1-Butanol, (22) Dimethyl Glutarate, (23) Anisole, (24) 2-Butoxyethyl Acetate
[1] Doss.turi.org
Trial Results:
Results from HSPiP Test:
# | Solvent | Soil Added | Soil Removed | Percent Removal | Rating |
1 | Toluene | 0.1235 | 0.1241 | 100.48 | 2 |
2 | Dimethyl carbonate | 0.0884 | 0.087 | 98.47 | 1 |
3 | Xylenes | 0.0722 | 0.0728 | 100.83 | 2 |
4 | Benzyl alcohol | 0.0362 | 0.0357 | 98.62 | 1 |
5 | Ethylene glycol | 0.0644 | 0.0633 | 98.29 | 1 |
6 | Methyl acetate | 0.0882 | 0.0933 | 105.78 | 5 |
7 | Undecane | 0.0538 | 0.0414 | 76.95 | 0 |
8 | Ethyl lactate | 0.054 | 0.0545 | 100.93 | 2 |
9 | Acetone | 0.0332 | 0.0336 | 101.20 | 3 |
10 | Ethyl acetate | 0.0456 | 0.0458 | 100.44 | 2 |
11 | Methanol | 0.0466 | 0.046 | 98.71 | 1 |
12 | Ethanol | 0.0821 | 0.0823 | 100.24 | 2 |
13 | 1,3 - dioxolane | 0.0425 | 0.043 | 101.17 | 3 |
14 | Diethyl carbonate | 0.0368 | 0.0373 | 101.35 | 3 |
15 | 1-Propanol | 0.0347 | 0.0346 | 99.712 | 1 |
16 | Iso-Propanol | 0.0296 | 0.0292 | 98.65 | 1 |
17 | Propylene carbonate | 0.045 | 0.0458 | 101.78 | 3 |
18 | Thiophene | 0.052 | 0.0521 | 100.19 | 2 |
19 | 1-Methoxy-2-Propanol | 0.0549 | 0.0549 | 100.00 | 2 |
20 | Dimethyl Sulfoxide | 0.0514 | 0.0514 | 100.00 | 2 |
21 | 1-Butanol | 0.0539 | 0.0536 | 99.44 | 1 |
22 | Dimethyl glutarate | 0.0354 | 0.0353 | 99.72 | 1 |
23 | Anisole | 0.0376 | 0.0377 | 100.27 | 2 |
24 | 2-Butoxyethyl acetate | 0.0473 | 0.047 | 99.37 | 1 |
Results from HSPiP:
The coating sphere determined by the HSPiP software was defined as D = 18.27, P = 8.77, H = 13.10
EHS Hazard Profile Analysis
One potential alternative chemical was identified using HSPiP, and the chemical was evaluated for overall environmental health and safety (EHS) compared to the original solvent blend. The following solvents were reviewed:
Original Solvent Blend:
1) Toluene
2) Acetone
3) Xylene
Alternatives:
4) 2-Pyridylmethanol
5) Propylene carbonate
6) Dimethyl glutarate
A detailed review of the (8) Pollution Prevention Options Analysis System (P2OASys.turi.org) EHS categories was conducted for original blend (Toluene, Acetone, and Xylene) and compared to the potential alternative as seen figure below.
Score | Description |
7-10 | High Hazards |
5-6 | Moderate Hazards |
2-4 | Low Hazards |
No Information Available | |
*Lower score = Lower toxicity/hazard. |
.
Original Solvent Blend | Alt. 1 | Alt. 2 | Alt. 3 | |||
Categories | Toluene | Acetone | Xylene | 2-Pyridylmethanol | Propylene carbonate | Dimethyl glutarate |
Acute Human Effects | 9 | 6 | 9 | 8 | 7 | 2 |
Chronic Human Effects | 8 | 7 | 8 | 5 | 2 | 2 |
Ecological Hazards | 8 | 2 | 8 | 2 | 2 | 3 |
Environmental Fate & Transport | 5 | 6 | 7 | 2 | 4 | 8 |
Atmospheric Hazard | 6 | 2 | 6 | 2 | 2 | 2 |
Physical Properties | 10 | 9 | 9 | 3 | 3 | 5 |
Process Factors | 7 | 5 | 7 | 2 | 4 | 4 |
Life Cycle Factors | 9 | 6 | 9 | 3 | 4 | 3 |
Weighted Average | 7.8 | 5.4 | 7.9 | 3.4 | 3.5 | 3.6 |
Original Blend Cleaner:
Proposed Identified Alternatives:
Based upon this analysis, 2-Pyridylmethanol, Propylene carbonate, and Dimethyl glutarate presents much lower hazards of concern compared to the original blend of Toluene, Acetone, and Xylene. The majority of the high hazards listed above in the current blend will be avoided with the identified alternatives with exception of a high hazard rating for both eye and dermal irritation. Which can be avoided with the correct personal protective equipment and engineering controls.
Success Rating:
Results successful using TACT (time, agitation, concentration, and temperature, as well as rinsing and drying) and/or other cleaning chemistries examined.Conclusion:
2-Pyridylmethanol, propylene carbonate, and dimethyl glutarate are considered to be safer alternatives to the current cleaning solvent blend. Samples will be requested, and the next step would be to undergo testing using the same performance methodology.