Trial Purpose:
Eight chemistries were tested in phase 1
Date Run:
02/05/1996Experiment Procedure:
The purpose of this trial is to complete phase one testing for Coatings Manufacturer. Eight different chemistries were tested at maximum recommended operating conditions. Chemistries that show potential will be used in phase two and phase three testing.
Twenty-four 2"x4" 304 Stainless Steel coupons were precleaned in a 20% solution of ND-Supreme in the Crest Ultrasonic console for 20 minutes at 140 F. The coupons were then rinsed in DI water for 2 minutes at 120 F. The coupons were run under air knives for two minutes and then dried for 30 minutes in a convection oven. The coupons were then allowed to cool down for 30 minutes.
After cooling the coupons were measured for a clean weight and then contaminated with both contaminants. The left side of the coupon was contaminated with Basecoat #51144 while the right side was contaminated with #51072. Curing lasted overnight. After curing, the coupons were weighed for a contaminated weight.
Cleaning was performed for 30 minutes at a Temperature of 160 F (+-5 F) in a 600 ml beaker with stir-bar agitation. The stir-bar setting was maintained constant for each chemistry tested. Cleaning time was for 30 minutes. All water-based chemistries were diluted to 50% while the rest of the chemistries were used at full strength. After cleaning, the coupons were immersed in tap water for 2 minutes at 100 F. (Tap water rinsing is not appropriate for some chemistries, but the rinsing will be more carefully evaluated in Phases II and III.) After rinsing the coupons were dried at 140 F in a convection oven for one hour. The coupons were allowed to cool down overnight, and then weighed the next day.
SUBSTRATE MATERIAL: 304 Stainless Steel Coupons
CONTAMINANTS: Durane Base Coatings #51072 & #51144
CONTAMINATING PROCESS USED: Rubbed on with swab and allowed to cure overnight
Trial Results:
Out of the eight different chemistries tested, four show a lifting mechanism (all four U.S. Polychem chemistries). To evaluate the effectiveness of these chemistries a scrape test was used on the remaining coating after cleaning. The other four chemistries use a dissolving mechanism on the coatings so gravimetric analysis was successful in evaluating the effectiveness of these chemistries.
GRAVIMETRIC RESULTS
U.S. Polychem Polyspray Jet 790P (50% solution)-#51072 coating was totally removed on all 3 coupons. #51144 Coating was scraped and could be pulled off of coupon with little effort.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 4 | 60.4205 | 61.4891 | 60.9933 | 0.4958 | 46.40% |
| 5 | 59.7666 | 60.8911 | 60.4188 | 0.4723 | 42.00% |
| 6 | 60.484 | 61.4893 | 61.0261 | 0.4632 | 46.08% |
| Average | 44.82% | ||||
| StDev. | 2.45% |
U.S. Polychem Polyspray Jet 790 XS (50% solution)- Effective on the #51072 (except on coupon #7). Scrape test showed that #51144 Coating could be pulled off with quite a bit of effort.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 7 | 59.9058 | 61.0715 | 61.0420 | 0.0295 | 2.53% |
| 8 | 60.1100 | 61.2037 | 60.7258 | 0.4779 | 43.70% |
| 9 | 60.6564 | 61.5477 | 60.9692 | 0.5785 | 64.91% |
| Average | 37.04% | ||||
| StDev. | 31.71% |
U.S. Polychem Polyspray Jet 790C (50% solution)- Not effective on the #51144 Coating at all.
| sample # | clean mass (g) |
mass with contamination (g) |
mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 10 | 60.0143 | 61.0900 | 60.4747 | 0.6153 | 57.20% |
| 11 | 60.7083 | 61.8142 | 61.1438 | 0.6704 | 60.62% |
| 12 | 60.2780 | 61.3615 | 61.2888 | 0.0727 | 6.71% |
| Average | 41.51% | ||||
| StDev. | 30.19% |
Frederick Gumm Cleppo 288-D (50% solution)- Effective on the #51144, but a longer cleaning time will be required to remove the #51072.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 13 | 60.3352 | 61.8657 | 61.2669 | 0.5988 | 39.12% |
| 14 | 60.5393 | 61.6671 | 60.6663 | 1.0008 | 88.74% |
| 15 | 60.7022 | 62.1118 | 61.8616 | 0.2502 | 17.75% |
| Average | 48.54% | ||||
| StDev. | 36.42% |
Ecolink Safe Strip (non-diluted)-Excellent Removal of the Basecoat #51072, A longer cleaning time will be necessary to remove the #51144
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 16 | 60.5761 | 61.6049 | 60.6560 | 0.9489 | 92.23% |
| 17 | 60.3589 | 61.4997 | 60.3737 | 1.1260 | 98.70% |
| 18 | 59.9049 | 61.1859 | 59.9882 | 1.1977 | 93.50% |
| Average | 94.81% | ||||
| StDev. | 3.43% |
.S. Polychem 69MC (non-diluted)- Lifts off the #51072 in 10 minutes. Scrape test showed that the remaining #51144 Coating could be removed easily after cleaning.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 19 | 60.2195 | 61.3182 | 60.8249 | 0.4933 | 44.90% |
| 20 | 60.4775 | 61.4268 | 60.9516 | 0.4752 | 50.06% |
| 21 | 60.2207 | 61.2342 | 60.6523 | 0.5819 | 57.41% |
| Average | 50.79% | ||||
| StDev. | 6.29% |
Terpene Technologies HTF 85B (non-diluted)-Almost as effective as the Ep-921, lower % removal on coupon 22 was due to a high contaminant load.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 22 | 60.0098 | 62.058 | 60.0875 | 1.9705 | 96.21% |
| 23 | 60.1060 | 61.1690 | 60.1068 | 1.0622 | 99.92% |
| 24 | 60.2287 | 61.1451 | 60.2314 | 0.9137 | 99.71% |
| Average | 98.61% | ||||
| StDev. | 2.09% |
Inland Technologies EP 921( non-diluted)- The most effective chemistry tested. Total removal occurred after 20 minutes.
| sample # | clean mass (g) | mass with contamination (g) | mass after cleaning (g) | contaminant removed (g) | Percent Removal |
| 25 | 60.5203 | 61.7187 | 60.5213 | 1.1974 | 99.92% |
| 26 | 59.3011 | 60.1552 | 59.3024 | 0.8528 | 99.85% |
| 27 | 60.2420 | 61.0863 | 60.244 | 0.8423 | 99.76% |
| Average | 99.84% | ||||
| StDev. | 0.08% |
Success Rating:
Results successful using TACT (time, agitation, concentration, and temperature, as well as rinsing and drying) and/or other cleaning chemistries examined.Conclusion:
The Safestrip, Cleppo-228C, PolySpray Jet 790C & 790XS were determined to be ineffective and should not be considered. The 69MC and the Polyspray Jet 790P will need a longer cleaning time to remove all of the urethane. The EP921 and HTF 85B performed excellent. The only concern may be the low flash point of the EP921 (146 F). Rinsing will definitely need to be looked in in phase II.
