Ashless Phosphorus-Containing Lubricating Oil Additives 91
ISO VG 22. The test was carried out on an automatic drilling machine, drilling holes of 18 mm
depth in a 40 mm thick disk of stainless steel type 304 with a feed rate of 0.13 mm/rev and at
1200 rpm. The test was concluded when either the drill broke or showed excessive wear. The results
in Table 3.11 [107] show a signifi cant improvement for the butoxyethyl phosphate over the isobutyl
phosphate, whereas the oleyl acid phosphate showed little activity. The reason for the poor behavior
of the acid phosphate is not known.
Also, in the fi eld of metalworking, phosphates have been claimed as components of hot forging
compositions [108,109].
3.5.3 ALKYL AND ARYL ACID PHOSPHATES
3.5.3.1 Non-ethoxylated
Although the range in commercial use is limited, acid phosphates are important components
of metalworking oils—frequently in combination with chlorparaffi ns. However, because of
TABLE 3.10
A Comparison of the AW/EP Performance of a Chlorparaffi n and an Alkyl or Aryl
Phosphate/Active Sulfur Combination in a Simple Oil-Based Cutting Fluid
Formulation
Formulation and Test Data A B C D
ISO 22 paraffi nic oil 92 95.7 96.9 —
Tri-isopropylphenyl phosphate — — — 1.0
Trialkyl phosphate — — 0.6 —
Active sulfur compound (40% S) — 4.3 2.5 2.5
Chlorinated paraffi n (40% Cl) 8 — — —
Four-ball wear test (ASTM D 4172)-mm 0.65 — — 0.43
Four-ball EP properties (ASTM D 2783)
Weld load (kgf) 400 — — 620
Seizure load (kgf) 80 — — 80
Load wear index 51 — — 104
Pin and V-block wear (ASTM D 3233)
Failure load (lb) > 3100 — — 2726
Drill Life test
Holes drilled to failure (EN24T mild steel at
1200 rpm/0.13 mm/min feed rate)140 100 280 200TABLE 3.11
Results of Drill Life Tests on Alkyl and Alkoxyalkyl Phosphates in the
Presence of Sulfur Carriers
Formulation (w/w) and
Test Data A B C D
Sulfur carrier 5.2 5.2 5.2 5.2
Tri-isobutyl phosphate — 4.17 — —
Tributoxyethyl phosphate — — 6.4 —
Oleyl acid phosphate — — 10.0
Neat oil 94.8 90.63 88.4 84.8
Holes drilled to failure 84 432 > 500 18