ANGUS Technical Data Sheet
CORRGUARD -95
®
Key Performance
Advantages
••Extends fluid life
••Minimizes leaching of cobalt
••Cost effective
High Performance Amino Alcohol for Metalworking Fluids
Today’s metalworking-fluid formulators require raw materials that are easy and
relatively safe to handle, provide multi-functional benefits and are of consistent high
quality. CORRGUARD®-95 (2-amino-2-methyl-1-propanol with 5% water), a primary
amino alcohol that has been used successfully in metalworking fluids for many years,
possesses these attributes. CORRGUARD-95 corrosion inhibitor is a strong base with
low molecular weight, and is a very efficient neutralizer of acidic ingredients such as
carboxylic acids and phosphate esters.
The benefits of the unique chemical and physical properties of CORRGUARD-95 include:
••Cost efficient alkaline pH development and neutralization of acidic components
••Reduced microbial degradation
••Stable emulsions at high pH
••Enhanced performance of triazine biocides
••Minimal ammonia release
••Minimizes leaching of cobalt
Metalworking Fluids
We make the best perform better.
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Typical Properties
Table 1
Cost Efficient pH Development
Synthetic Fluid with CORRGUARD-95 vs. TEA-99
The following are typical properties of CORRGUARD-95.
They are not to be considered product specifications.
Base strength (pKa @ 25°C)
9.82
Molecular weight (of 2-amino-2-methyl-1-propanol)
89.1
pH (0.1M Aqueous)
11.3
Amine Value (mg KOH/g)
592
Vapor pressure @ 20°C mm Hg (anhydrous)
0.34
Specific gravity @ 25°C
0.942
Weight per gallon @ 25°C
7.85 lb
Viscosity @ 25°C (77°F)
147 cp
@ 10°C (50°F)
561 cp
Freezing point
-3°C/28°F
Ingredients, wt %
Deionized Water
Inversely Soluble Ester [A]
Chlorinated Fatty Acid [B]
Amine Carboxylate [C]
Amino Alcohol
Biocide [D]
pH @ 20:1 Dilution
TEA-99
CORRGUARD-95
TEA-99
52.8
6.0
9.2
6.0
25.0
1.0
100.0
60.3
6.0
9.2
6.0
1.5/16.0
1.0
100.0
8 .9
9.0
Flash point
Tag Closed Cup
78°C/172°F
Tag Open Cup
83°C/182°F
The low molecular weight of CORRGUARD-95 means more
amine per unit weight is available for neutralizing acidic
contaminants, such as byproducts of microbial growth,
oxidation, etc. This is often referred to as reserve alkalinity.
The relative amounts of reserve alkalinity for equal weights of
CORRGUARD-95 and TEA-99 are shown in Figure 1. This shows
the volume of 1N hydrochloric acid required to completely neutralize
one pound (454 grams) of each amine. CORRGUARD-95 provides
60% more reserve alkalinity than TEA-99.
Surface tension
As supplied
37 dynes/cm
In 10% aqueous solution
58 dynes/cm
Key Benefits
Cost Efficient Alkaline pH Development
Development and maintenance of alkaline fluid pH is an
important factor in determining fluid performance and service
life. Inadequate pH control can result in loss of fluid stability,
corrosion of tools and parts, and increased opportunity for
microbial degradation of the fluid. Proper pH control can help
reduce end-user operating costs by minimizing fluid changes,
waste disposal, and downtime.
Figure 1
Reserve Alkalinity
CORRGUARD-95 vs. TEA-99
CORRGUARD-95 corrosion inhibitor is the product of choice
for developing and maintaining alkaline pH because it has
high base strength, low molecular weight, and is less reactive
with atmospheric CO2 than other common amines. High base
strength, along with low molecular weight, means less amine is
needed to develop alkaline pH. CORRGUARD-95 may improve
cost efficiency when used in combination with amines of
lower base strengths and higher molecular weights, such as
triethanolamine (TEA-99). This is particularly true with fluids
formulated at pH 9 or above, where the 100-fold greater base
strength of CORRGUARD-95 relative to TEA-99 is a major
advantage. An example of this benefit is shown in Table 1 for
a synthetic fluid. Replacement of 25 parts TEA-99 with 1.5
parts CORRGUARD-95/16 parts TEA-99 resulted in equal pH
development in the diluted fluid.
Amine retention and reactivity with atmospheric CO2 in a circulating
metalworking fluid system can significantly influence pH stability.
Results of a 14-day aquarium study (Figures 2 & 3) reveal that
CORRGUARD-95 corrosion inhibitor is well retained in a recirculating aqueous solution. In addition, CORRGUARD-95 is less
reactive with atmospheric CO2 than other strong amines, resulting
in better pH stability.
2
Figure 2
Amine Retention/
Carbon Dioxide Reactivity
Tankside Benefits
Tankside pH adjustment is sometimes needed to maintain fluid
performance and longevity, and CORRGUARD-95 corrosion
inhibitor is an extremely efficient product for adjusting pH.
Figure 4 compares the amounts of CORRGUARD-95, TEA-99,
and potassium hydroxide (45% aqueous) needed to raise the
pH of 100 gallons (378.5L) of a typical use-diluted synthetic fluid
from 8.0 to 9.0. CORRGUARD-95 and KOH-45% are significantly
more efficient than TEA-99. CORRGUARD-95 is the product of
choice for tankside pH control due to its efficiency and safety
advantages.
Figure 4
Tankside pH Adjustment*
Figure 3
pH Stability
*Synthetic dilution pH adjusted from 8.0 to 9.0
Efficient Neutralization of Acidic Components
Many metalworking fluid ingredients must be neutralized to
make them water soluble and to perform properly. Examples
include phosphate esters, mono- and dicarboxylic acids, fatty
acids, and boric acid. Neutralization efficiency is related to the
combination of base strength and molecular weight of the
neutralizer. Performance depends upon the types of neutralizers
and acidic materials that are used.
Table 2
Reserve Alkalinity
Soluble Oils with CORRGUARD-95 and TEA-99
CORRGUARD-95/
Naphthenic Oil [E]
Sodium Petroleum Sulfonate [F]
Tall Oil Fatty Acid [G]
Propylene Glycol n-Butyl Ether [H]
Amino Alcohol
Deionized Water
Biocide [D]
Reserve Alkalinity @ 20:1 Dilution
(mL 0.1N HCl/50g)
pH @ 20:1 Dilution
Amine Cost/ 100 lbs
Raw Material Key
[A] Inversol 170
Dover Chemical Company
[B] CW-105A
Dover Chemical Company
[C] Synkad 6000
Dover Chemical Company
[D] BIOBAN P-1487™
CORRGUARD-95
TEA-99
CORRGUARD-95/TEA-99
79.25
14.00
2.40
1.60
0.75
1.00
1.00
78.00
14.00
2.40
1.60
2.00
1.00
1.00
78.50
14.00
2.40
1.60
0.5/1.0
1.00
1.00
2.70
9.00
$1.26
4.10
8.70
$1.00
3.60
8.90
$1.34
CORRGUARD-95, with an effective molecular weight of ~95
as supplied (Active Ingredient = 89.1), is a much more efficient
neutralizer than TEA-99 (molecular weight 149). ANGUS
recommends use of combinations of these products to balance
cost and performance.
Stable Emulsions at High pH
When formulating soluble oils, one of the main goals is
achievement of a stable emulsion at the desired pH. It is often
desirable to formulate emulsions at pH 9 or greater, and an
amine that provides good stability at higher pH levels is required.
The Dow Chemical Company
[E] Hydrocal 100
Calumet Refining Company
[F] Actrabase PS-470 Afton Chemical
[G] Latol 4 Afton Chemical
[H] DOWANOL™ PNB
The Dow Chemical Company
As shown in Table 3, it is often difficult to formulate a stable
emulsion in the higher pH range with TEA-99; the soluble
oil formula shown in Table 2 was used for this comparison.
CORRGUARD-95 can be used alone or in combination with
TEA-99 to provide stable emulsions at elevated pH.
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Table 3
Stable Emulsions at Higher pH
In a similar test of four synthetic metalworking fluids without
biocide, two based on TEA and two based on CORRGUARD-95,
the fluids containing CORRGUARD-95 showed superior
bioresistance to the TEA-based fluids. The data is shown in
Figure 6.
20:1 Dilution (tap water)
Amine System
TEA-99
TEA-99
CORRGUARD-95/TEA-99
CORRGUARD-95
CORRGUARD-95
*on 50 mL emulsion
pH
8.7
8.8
8.9
9.0
9.2
mL Cream @
24 hours*
1 /2
>1/2
<1/2
1 /2
1 /3
Figure 6
Bacterial Resistance - Synthetic Metalworking Fluid
Resistance to Microbial Degradation
Microbial degradation of fluid components results in loss
of performance and shortened fluid life. Recognizing this,
metalworking fluid formulators have searched for more
“bioresistant” materials from which to build their fluids.
However, the term bioresistant is often confused with the
term biocidal. In order to clarify the issue, we define the
term bioresistance as follows: A bioresistant material is one
which, while it does not kill microorganisms, is not readily
chemically decomposed by microbial attack. Simply put, a
bioresistant material does not provide a ready food source for
microorganisms. Under equal conditions, a fluid made from
bioresistant ingredients will typically last longer than one made
from biosupportive ingredients.
pH Stability in Microbially Contaminated Systems
The degree to which amino alcohols biodegrade in metalworking
fluid formulations has an impact on the pH stability of the fluid.
The more bioresistant the fluid components, the less microbial
growth occurs, and hence fewer acidic byproducts are produced.
In addition to its reserve alkalinity and efficient pH boosting
properties, CORRGUARD-95 corrosion inhibitor, as a bioresistant
amine, exhibits superior pH stability in the presence of microbial
contamination. The data in Figure 7 shows pH stability of
a synthetic metalworking fluid based on CORRGUARD-95
compared to that of the same fluid based on TEA/KOH. The
fluids were dosed with a mixed inoculum of bacteria and fungi
and then tested for pH change after 12 weeks. The results
show that fluids containing CORRGUARD-95 exhibit superior pH
stabilization as compared to fluids with TEA.
Several common acidic components were diluted to 5000 ppm
in distilled water and neutralized to pH 9.5 with CORRGUARD-95
corrosion inhibitor or a blend of TEA-99 and KOH. These
salt solutions were given a mixed inoculum of 106 Colony
Forming Units (CFU)/mL bacteria and 104 CFU/mL fungi. The
CORRGUARD-95 salts were all resistant to bacterial growth
while the TEA salts were biosupportive as shown in Figure 5.
Figure 5
Biostability of Amine-Based
Metalworking Fluid Additives*
Figure 7
pH Stability – Synthetic Metalworking Fluids
*0.5% acid solutions neutralized to pH 9.5 and inoculated at start with mixed
bacterial/fungal inoculum
“0” on this chart indicates no change from starting pH
4
Enhanced Performance of Triazine Biocides
This study also revealed fluids containing CORRGUARD-95
corrosion inhibitor that were microbially challenged released
significantly less NH3 than fluids containing ethanolamines
(Figure 9). Although a small amount of NH3 was released
initially from the CORRGUARD-95 fluid, the quantity released
over the 180-day test period was small compared with that
released by ethanolamine-based fluids. Olin concluded that
MEA, DEA, and TEA contribute to ammonia accumulation, while
CORRGUARD-95 does not.
Triazine biocide [hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine] is
an effective antibacterial agent in metalworking fluids, but does
not normally control fungal growth except at very high use levels.
CORRGUARD-95 has been shown to enhance the antifungal
performance with triazine biocide. An example is shown in
Figure 8 for the synthetic fluid formulations in Table 4. Fluid with
the triazine/CORRGUARD-95 system resisted fungal growth for
three weeks, while fluids containing triazine and TEA-99 or TEA/
KOH failed at one week. CORRGUARD-95 is not a biocide and is
not intended for use as an antimicrobial.
Figure 9
Ammonia Release Study
Figure 8
Triazine/CORRGUARD-95 Antifungal Benefits
Cobalt Leaching
*Failure is 1000 CFU/mL
Leaching of cobalt binder from cemented tungsten-carbide
during the manufacturing of carbide tools introduces potential
safety and environmental hazards:
Table 4
Synthetic Fluid Formulations
(Triazine/CORRGUARD-95 Antifungal Study)
••The presence of dissolved cobalt in machining fluids can create
dermatitis and inhalation problems for workers handling these
fluids.
Ingredients, wt. %
Deionized Water
Amine Carboxylate [I] 5
Inversely Soluble Ester [A]
Amino Alcohol 1
KOH (45%)
Triazine [J]
pH @ 20:1 Dilution
Amine Cost/100 lbs
T EA-99
TEA-99/
KOH
73
5
10
0
–
2
71
5
10
10
2
2
CORRGUARD-95
10
4
–
2
100
100
100
$10.00
$10.20
$8.00
8.8
9.6
(includes KOH)
••Environmental regulations may limit the discharge of heavy
metals such as cobalt into waterways.
79
In carbide tool production, it is important to select fluid
ingredients that do not leach (dissolve) cobalt from the tool
material. Certain fluid components, such as amino alcohols and
amine-based additives (e.g. amides and carboxylate salts), are
more problematic than others.
9.7
Since amino alcohols can leach cobalt from cemented carbide,
a laboratory study was conducted to compare the leaching
properties of various products. A one percent solution of each
amine was prepared in deionized water and the pH of each
adjusted to 9.0 with acetic acid. The amine solutions were
vigorously mixed for five days with carbide swarf. At the end of
the test period, the fluids were filtered and the filtrates analyzed
by atomic absorption for dissolved cobalt. The test results
are shown in Figure 10. The solution with CORRGUARD-95
corrosion inhibitor had the least dissolved cobalt of all the amine
solutions tested. In fact, CORRGUARD-95 leached only slightly
more cobalt than deionized water with no amine (control).
CORRGUARD-95 is therefore the amine of choice for fluids
intended for carbide tool manufacturing.
Ammonia Release
Release of ammonia (NH3) from metalworking-fluid systems can
result in worker complaints and, in severe cases, evacuation and
shutdown of operations.
A study by Olin Chemicals (now Lonza) showed that NH3
release is associated with microbial degradation of triazine
biocide, monoethanolamine (MEA), diethanolamine (DEA), and
triethanolamine (TEA). NH3 release occurs when fluid pH is
adjusted upward, converting dissolved ammonium hydroxide
(from microbial degradation) into its gaseous form.
5
Figure 10
Cobalt Leaching Study
Foamy salts can lead to foamy metalworking fluids. In a study
of soluble oils containing tall oil fatty acid and various strong
amines, the fluid with CORRGUARD-95 corrosion inhibitor
generated the least foam (Figure 12). This test, using a “Waring
Blender,” is very severe, simulating a high speed grinding
application.
Figure 12
Waring Blender Foam Results
Low Foam
Foam generation is undesirable because it results in loss of
cooling and lubrication, and can create a mess in the plant.
The addition of defoamers may result in concentrate stability
problems and poor adhesion of coatings to finished parts.
Several types of fluid components (fatty acid soaps, non-ionic
surfactants, etc.) can contribute to foaming. Studies have shown
that the amine portion of various salts can significantly affect
foaming potential. Test results with 0.5% solutions of amine
salts at pH 9.5 are shown in Figure 11.
Figure 11
Foaming Results
Cylinder Shake Test of Amine Salt Solutions
6
Summary
CORRGUARD-95 offers numerous benefits to metalworking
fluid formulators. In cases where a particular benefit is
desired, for example bioresistance or low cobalt leaching,
ANGUS recommends formulating with CORRGUARD-95
exclusively. However, in many cases a balance of properties
is desired. To achieve the desired cost/ performance, the use
of CORRGUARD-95 with weaker amines such as TEA may be
preferred. Please contact your local ANGUS representative for
technical assistance.
Product Stewardship
ANGUS encourages its customers to review their applications
of ANGUS products from the standpoint of human health and
environmental quality. To help ensure that ANGUS products
are not used in ways for which they are not intended, ANGUS
personnel will assist customers in dealing with environmental
and product safety considerations. For assistance, product Safety
Data Sheets, or other information, please contact your ANGUS
representative at the numbers provided in this document.
When considering the use of any ANGUS product in a particular
application, review the latest Safety Data Sheet to ensure that
the intended use is within the scope of approved uses and can
be accomplished safely. Before handling any of the products,
obtain available product safety information including the Safety Data
Sheet(s) and take the necessary steps to ensure safety of use.
Contact Information
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Notice: No freedom from infringement of any patent owned by ANGUS or others is to be inferred. Because use conditions and applicable laws may differ from one location to another
and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer’s use and for ensuring that
Customer’s workplace and disposal practices are in compliance with applicable laws and other government enactments. The product shown in this literature may not be available for
sale and/or available in all geographies where ANGUS is represented. The claims made may not have been approved for use in all countries. ANGUS assumes no obligation or liability
for the information in the document. References to “ANGUS” or the “Company” mean the ANGUS Chemical Company legal entity selling the products to Customer unless expressly
noted. NO WARRANTIES ARE GIVEN: ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.
Published March 2016 Form No. COR-1734-0415-TCG
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