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To evaluate supplied products for Green Seal GS 34 degreasing standard.
Two types of soils were prepared individually. The first soil, maintenance soil, consisted of 10 grams of carbon black, 10 grams iron oxide, 100 ml WD-40, 100 ml hydraulic oil, and 100ml gear oil. Each component was placed in a 750 ml beaker and mixed for 20 minutes at room temperature using a magnetic stirrer. The second soil, production soil, was made by mixing 200ml Quench Oil and 200 ml cutting oil for 20 minutes at room temperature using a magnetic stirrer in a second 750 ml beaker.
Approximately 100 mg of each soil was applied to a precleaned and preweighed stainless steel coupon onto one side only with a hand swab. No soil was applied to the control coupons. The maintenance soil for the first set of coupons was baked in an oven for 30 minutes at a temperature of 40° C (105 F). For the production soil, the second sets of coupons were baked in an oven for thirty minutes at 105° C (220 F). The coupons were then allowed to cool to room temperature and weigh a second time (soiled mass=B).
Four products were used at room temperature. Four 500 mL beakers and four 400 ml beakers were filled with enough fresh cleaner solution to completely submerge the coupons in the degreasing solution without any overflow. Each coupon was suspended in a beaker, allowing the entire contaminated surface to be submerged in the cleaning solution. The coupons were washed for 20 minutes using immersion cleaning only.
The washing was followed by two rinse steps. The coupons were drained for 30 seconds prior to each rinse step. For each rinse step a 20 minute soak was utilized. After the two rinse steps, all coupons were first allowed to air dry for 30 minutes and then dried in an oven at 105° C for 30 minutes. The coupons were cooled to room temperature and final weights were measured (mass of coupons after cleaning = C).
The control coupons were examined to determine if there were any visible signs of corrosion. Next, the control coupons were weighed to determine if there was any loss of mass, which might occur if corrosion was in progress; or gained mass, which might occur if the degreaser had left a residue on the coupons. The following equation was applied:
[MCC – MCB] < .1mg ( which is the maximum balance error).
Where: MCC = mass of the control coupon after washing and rinsing
MCB = mass of the control coupon before washing and rinsing
For the cleaned coupons, the amount of residual soil per surface area was calculated, using the following formula: RS = (C – A)/ AR
Where: RS = amount of residual soil (mg/s²)
C = mass of the coupon after cleaning
A = initial coupon mass
Ar = surface area = .00387 m²
If the average residual maintenance soil loading, and the average residual performance soil loading are each less than 2,000 mg/m², the degreaser meets the cleaning performance criteria.
The maintenance soil was more difficult than the production soil for all of the products to remove. Only the CRC Heavy Duty Degreaser removed enough soil to pass the GS 34 requirement. The second most effective product was the Liquifix Multipurpose degreaser. The Supersoy product from CRC left behind a lot of residue on the coupons. Both the Heavy Duty Degreaser and Liquifix degreaser met GS 34 cleanliness levels on the production soil.
|MX2-MX3||MX2-MX1||MX3-MX1||mg/cm2||Ave CEF||Ave RC||mg/m2|
|CRC Supersoy Maintenance Soil|
|CRC Heavy Duty Cleaner Maintenance Soil|
|Liquifix Multipurpose Degreaser Maintenance Soil|
|Spartan SD-20 Maintenance Soil|
|CRC Supersoy Production Soil|
|CRC Heavy Duty Production Soil|
|Liquifix Multipurpose Degreaser Production Soil|
|Spartan SD-20 Production Soil|
The control coupons were weighed to determine if there was any gain/ loss of mass. The Supersoy left significant residue on the control coupons, the CRC Heavy Duty cleaner left no residue and the Liquifix product left a small amount of residue. The table lists the weight changes for the control coupons.
|CRC Supersoy - Maintenance Soil||0.0731||residue|
|CRC Heavy Duty Cleaner - Maintenance Soil||0.0001||no residue|
|Liquifix Multipurpose Degreaser - Maintenance Soil||0.0092||little residue|
|Spartan SD-20 - Maintenance Soil||-0.0094|
|CRC Supersoy - Production Soil||0.0184||residue|
|CRC Heavy Duty Cleaner - Production Soil||0.0003||no residue|
|Liquifix Multipurpose Degreaser - Production Soil||0.0036||little residue|
|Spartan SD-20 - Production Soil||0.0009|
|GS 34 target <2000 mg/m2||GS 34 mg/m2|
|CRC Heavy Duty Cleaner||336||586|
|Liquifix Multipurpose Degreaser||5624||1473|
Success Rating:A follow up test, usually based on company input.
0nly one of the supplied products, CRC Heavy Duty Cleaner, surpassed the required performance level set by the GS 34 standard. The Liquifix multipurpose product met the required residual level for the Production soil but did not meet the level for the maintenance soil. On average, the product did remove more than 85% of the soils using immersion cleaning.