Note: Descriptions are shown in the official language in which they were submitted.
5452 (2)
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SOLUBLE-OIL CUTTING FLUID
This invention relates to a soluble-oil and to an oil-in-water
emulsion containing the soluble-oil, which emulsion is suitable for
use as a gutting fluid
Soluble-oil emulsions are well known as cutting fluids. The term
"soluble-oil" although used throughout the industry it, in fact, a
misnomer because the constituents are not soluble in water. The
soluble-oils are basically mineral oils blended with emulsifiers and
other additives which, when added to water and stirred, form an oil-
in-water emulsion. The emulsion allows the good cooling properties of
water to be utilized in the metal working process whilst the oil and
additives provide lubrication and corrosion inhibiting properties
The one or more emulsifiers included in the soluble-oil may not
readily form a stable blend with the mineral oil and so a coupling
agent is commonly required to bind the emulsifier to the oil,
Conventional coupling agents include, for example, volatile alcohols
such as sec. buttonhole bottle oxitol or cyclohexanol. The volatility of
these coupling agents means that over a period of time coupling agent
is lost from the soluble-oil by vaporization This loss of coupling
agent reduces the stability of the soluble-oil and is often associated
with an objectionable smell. Further, the coupling agents have
relatively low flash points which means that great care just be taken
when they are blended or otherwise handled.
The present invention relates to a soluble oil which is
relatively stable without the need for a conventional coupling agent.
Thus according to the present invention a soluble-oil suitable,
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when diluted with water, for use as a cutting fluid comprises an
alkali or alkaline-earth metal alkyd Bunsen sulphonate, a fatty acid
diethanolamide, A mixed alkanolamine borate, a polyisobutene-
succinlmide and a major proportion of mineral oil.
Soluble-oil emulsions may become contaminated by bacteria, yeasts
and molds The growth of these microorganisms may cause problems
such as emulsion breakdown, the production of slimes and finagle mats
and the evolution of foul odors. Besides are often therefore
included in soluble-oil formulations to control microbial growth. It
lo has surprisingly been found that at least some of the soluble-oils
according to the present invention are bio-static even though
conventional besides are not included in the formulation.
Suitably, the soluble-oil according to the present invention
comprises the following amounts of the components;
EYE Amount (I o total White)
Alkali or Alkaline-earth metal alkyd
Bunsen sulphonate 2 - 10
Fatty acid diethanolamide 2 - 3
Mixed alkanolamine borate 2 - 5
20 Polyisobutenesuccinimide 2 - 6
Mineral Oil balance
The alkali metal or alkaline-earth metal of the alkyd Bunsen
sulphonate is preferably potassium or calcium or more preferably
sodium. The alkyd group is preferably derived from polypropylene.
The alkali or alkaline-earth metal alkyd Bunsen sulphonate may be
produced by known methods from synthetic ~ulphonic acids. Preferably
the molecular weight of the compound is from 400 to 520. high
molecular weight improves the corrosion inhibiting properties of the
soluble oil whereas a low molecular weight improves emulsion stability
and so the choice of molecular weight involves a compromise. Mixtures
of alkyd Bunsen sulphonates may be used.
The fatty acid diethanolamides are preferably formed by the
reaction of diethanolamine with naturally occurring fatty acids having
from 12 to 20 carbon atoms. The fatty acids may be saturated or
unsaturated but are preferably unsaturated.
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The mixed alkanolamlne borate comprises the reaction products of
more than one alkanolamine with boric acid. The alkanolamines may be
selected from monoethanolamine, diethanolamine, triethanolamine,
NUN dim ethyl ethanol amine. A preferred combination of alkanolamines
5 it moo- and di-ethanolamine.
The polyisobutenesuccinimide is preferably over based with excess
amine and preferably has a molecular weight of from 1000 to 3000.
The soluble-oil formulation also preferably contains a small
amount of distilled water e.g. from 0 to 2% by weight of the total
weight of the soluble-oil. The distilled water improves the stability
of the blend.
A deforming agent such as a Friedel Rafts wax may also be
included in the soluble oil. A suitable wax is SICILY wax SO 105
supplied by Weber. The amount of deforming agent is preferably in the
range 0-0.05% by weight of the total weight of the soluble-oil.
The soluble-oils according to the present invention may also
contain other conventional additives for soluble-oils such as for
example corrosion inhibiting additives. A suitable commercially
available corrosion inhibitor comprises a solution of Bunsen
sulfonamide Huxley carboxylic acid in water and N,N-dimethyl amino
propel amine. This commercially available corrosion inhibitor is
particularly effective when supplemented with triethanolamine.
Alternatively, a mixture of triethanolamine and other carboxylic acids
such as, for example, caprylic acid or caprice acid may be used to
inhibit corrosion. Typically, the corrosion inhibitor is used up to
an amount of 2% by weight of the total weight of the soluble-oil, I
the corrosion inhibitor comprises a mixture of triethanolamine and a
carboxylic acid then the two compounds may be present in equal weights
up to a combined weight of 2% of the total weight of the soluble-oil.
If a biocidal soluble-oil is required, a conventional buzzed may
be included in the formulation.
It is to be understood that the optional components of the
soluble-oil are included in the composition in place of some of the
mineral oil.
Although a wide range of mineral oils Jay be used in the soluble-
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2 243
oil formulations according to the present invention, base oils
design Ed 100 to 500 solvent neutral have been found to be
particularly suitable, Leo paraffinic oils typically having kinematic
viscosities at 40C in the range 12 to 100 cyst.
The soluble-oil according to the present invention it relatively
stable and when mixed with water readily forms an emulsion which may
be used in a number of metal working operations e.g. cutting, drilling
and grinding. Preferably, the emulsion has a water to soluble-oil
ratio of from 10:1 to 40:1 although higher and lower dilutions may be
useful in certain applications.
The invention is illustrated with reference to the following
example.
Example 1
Two soluble-oil formulations were prepared by mixing the
15 following components:-
Component Amount (% by weight)
Formulation A Formulation B
Sodium alkyd Bunsen sulphonate 6.25 6.25
(sold by Paramins under the trade name
20 Synacto 416)
Fatty acid diethanolamide 2.5 2.5
(sold by Unichema under the trade
name Prichem~1859)
Mixed alkanolamine borate 2.5 2.5
(sold by Hiawatha Chemicals under the
designation MOB)
30 Polyisobutenesuccinimide (sold by
Laboriously under the designation L 5602 2.5 2.5
Sicily wax SO 105 - 0.01
(supplied by Weber)
Distilled Water 1.0
Paraffinic Base Oil 86.25 85.24
The sodium alkyd Bunsen sulphonate had an average molecular
weight of 440 and was used as a 60~ by weight solution on a paraffinic
mineral oil. The fatty acid diethanolamine was oleic acid
trudge aureole
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diethanolamide and was approximately 25% over based with excess
diethanolamine. The mixed alkanolamine borate was a mixture of boric
acid, monoethanolamine and diethanolamine in the approximate weight
ratio 30:33:35, The polyisobutene succinimide was formed by the
reaction between a polyisobutene having a molecular weight of
approximately 1000,succinic acid android and diethanolamine and was
over based with a small excess of NUN dim ethyl ethanol amine.
The thermal stability of each formulation was tested after
14 days at temperatures in the range -5C to 50C using a method based
Oil the Institute of Petroleum test method IT 311, Thermal Stability of
Emulsifiable Cutting Oil. Both formulations were very viscous at
temperatures of 0C and below but were stable on warming. Formulation
B was also stable at temperatures up to 50C. Formulation A became
unstable at temperatures above 40C. However, in the presence of 0.5%
wit of water, Formulation A was also stable up to 50C.
Samples of the two formulations were mixed with mains tap water
at ratios of water to oil of from 10:1 to 25:1. The oil readily
emulsified in the water at each dilution and each emulsion was
subjected to the Institute of Petroleum standard test method IT 125
Aqueous Cutting Fluid Corrosion of Cast Iron. There was no visible
staining or pitting at the lower dilutions and the corrosion at the
highest dilutions was hardly perceptible.
The propensity to foam of Formulation B was less than that of
Formulation A as determined by the Institute of Petroleum standard
test method IT 312, Frothing Characteristics of Emulsifiable Cutting
Oil. This is presumably due to the inclusion in Formulation B of
Sicily wax, a known deforming agent.
A test rig was used to evaluate the microbial degradation of the
soluble-oil emulsions in a simulated workshop operation. The rig
comprised a reservoir for the cutting fluid and an air lift pump to
transfer the fluid from the reservoir to a funnel containing metal
cuttings, the funnel being mounted over the reservoir so that the
fluid drained back into the reservoir. Duplicate samples of
Formulation A diluted with mains tap water in the ratio of water to
oil of 20:1 were tested in the test rig. An inoculum prepared from a
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mixed culture of fungi and bacteria originating from a spoiled cutting
oil emulsion was added to the test samples so that an initial total
viable count of approximately 106 micro-organisms per milliliter of
emulsion was obtained. Air was passed through the rig to circulate
and aerate the fluid during normal working hours from Monday to Friday
each week. Each Monday morning, viable counts of aerobic bacteria,
yeasts and mounds were prepared and the presence of sulfide producing
bacteria, evolution of HIS, pal and emulsion stability were determined.
Up to the end of 14 weeks, the emulsion had not evolved HIS or
encouraged yeast, mound or finagle growth. The total viable bacteria
count remained at approximately 106 organisms per milliliter of
emulsion throughout the test. The strength of the emulsion was
relatively constant throughout the test and the pi which was initially
9.5 fell to around I after 12 days and then remained at this value
for the remainder of the test period.
The results show that Formulation A, which contains no
conventional buzzed or coupling agent, forms a stable emulsion which
has biostatic properties and does not evolve HIS.
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Example 2
Two soluble-oil formulations were prepared by mixing the
following components:-
Amount I by weight)
Formulation C Formulation D
Sodium alkyd Bunsen sulphonate 9 5 9.5
tSynacto 416, ox Paramins)
Fatty acid diethanolamide 2.5 2.5
10 (Prichem 1859, ox Unichema)
Mixed alkanolamine borate 2.5 2.5
(MOB 12* ox Hiawatha Chemicals)
15 Pol~isobutenesuccinimide 5.0 5.0
(L 5602~ ox Laboriously)
Arylsulphonamidocarboxylic acid in - 1.0
water and amine (Hostacor Ho sold by ~1oechst)
Triethanolamine - 1.0
Sicily wax So 105 0.01 0.01
(supplied by Weber)
Distilled Water 2.0 2.0
Paraffinic Base Oil 78.49 76.49
Formulation D is similar to Formulation C except that it contains
a corrosion inhibiting mixture comprising triethanolamine and
Hostacor H. Hostacor H is a commercially available corrosion
inhibitor comprising a solution of Bunsen sulfonamide Huxley
carboxylic acid in water and N,N-dimethyl amino propel amino
The thermal stability of each formulation was tested after
14 days at temperatures in the range O to 60C using a method based on
the Institute of Petroleum test method IP311, Thermal Stability of
Emulsifiable Cutting Oil. Both formulations were stable throughout
the temperature range.
Each of the formulations were mixed with mains tap water at
ratios of water to soluble-oil of from 10:1 to 40:1. The soluble-oils
readily emulsified in the water at each dilution. Each of the
emulsions was subjected to the Institute of petroleum standard test
method IP125, Aqueous Cutting Fluid Corrosion of Cast Iron.
Formulation C showed no pitting or staining up to dilutions of 20:1
Trudy
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and Formulation D showed no pitting or staining up to dilutions of
40:1.
The results show that both formulations, which contain no
convention Ed coupling agent, form relatively stable emulsions with
water and that the inclusion of the triethanolamine and Hostacor H
improve the corrosion inhibiting properties of the soluble-oil.
