Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE rNVENTION
FELD OF THE rNVENTION
This invention relates to lubricating oil compositions for automated
can filling and se~min~ and related eq -ipm~nt used in food proces~in~ plants.
DESCRIPTION OF THE RELATED ART
Can seamers are large, heavy machines that roll the lid of the can
over the can body and form the seam on the can top. The cans body can be
made from al~min-~m timplate (templated steel), composite (al~ .... foil or
polymer sheet or cardboard) or plastic. The can seamer typically also employs a
rotary can roller and conveyor equipment. Lubricants for use in can se~ming and
roller or conveyor equipment should have FDA approval or employ FDA
approved components, e.g. base oil such as white oil, polyalphaolefins, and
approved additives such as anti-wear, rust inhibitors and emulsifiers, if the
seamers are employed in the food or pharmaceutical industry. 21 CFR 178.3570
recites the Food and Drug A-1minictration regulations governing lubricants with
incidental food contact.
SUMMARY OF THE INVENTION
The present invention is a lubricating composition for use in can
se~min~ and related equipment used in the food and ph~ ceutical industry,
said lubricating composition comprising a major portion of a food grade base oiland a minor portion of an additive comprising polyglyceryl 3-6 mono-oleates.
DETAILED DESCRIPTION OF THE INVENTION
The lubricating composition useful for can se~ming equipment
comprises a major amount of a food grade lubricating oil base stock and a minor
portion of polyglyceryl 3-6 mono-oleate.
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The food grade lubricating oil base stock may be selected from 10
to 5000 cSt ~ 40C food grade natural or synthetic base stock oil, preferably 30to 300 cSt (~ 40C food grade natural or synthetic oil and mixtures thereof.
Natural oil base stock oil is i~Pntified as white oil, a colorless,
transparent liquid mixture of pa~s. The white oil is produced by the distilla-
tion of higher boiling petroleum fractions (330-390C) which fraction is
extracted to remove aromatics, dewaxed, hyd,oll~,aled to remove sulfur and
nillogell compounds and olefins. Treatment may also include purification using
sulfilric acid, caustic soda, decalcination by carbon filtration, etc. The
production of white oils is well known in the art.
Synthetic base stocks suitable for use include food grade poly-
alphaolefins and stocks useful as thickeners including polyisobutylenes and
polybutenes as approved in 21 CFR 178.3570.
The food grade base stock comprises 94 to 99 wt% preferably 96
to 98 wt% of the subject lubricating composition.
The composition also contains a minor portion of polyglyceryl 3-6
mono-oleate, specifically triglyceryl mono-oleate, tetraglyceryl mono-oleate,
hexaglyceryl mono-oleate and n i~lwes thereof, preferably tetraglyceryl mono-
oleate also known as polyglyceryl-4-oleate, the oleic acidmonoester of a glycerin
polymer containing an average 4 glycerin units.
The polyglyceryl mono-oleate is used in an amount in the range 1
to 6 wt%, preferably 2 to 4 wt%.
The lubricating composition has a final form~ te~1 viscosity in the
range 20 cSt (~ 40C to 350 cSt (~ 40C. The final product viscosity can be
ne~ by using a single base stock which itself possesses the viscosity of the
final product or by using a number of base stocks from those recited above and
mixing them together to produce a blend having the desired viscosity or by
addition of an FDA approved thickener stock material such as polybutene or
polyisobutylene .
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The formulated oil may contain other additives, including rust
inhibitors/anti wear agents, in an amount in the range 0.01 to 2.0 wt%, prefer-
ably 0.1 to 0.5 wt%, anti oxidants in an amount in the range 0.01 to 1.0 wt%,
plefe~ably 0.1 to 0.5 wt%. These additional additives must likewise be FDA
approved. Examples of FDA approved materials are food grade butylated
hydroxy toluene BHT (anti oxidant) and the salt of mixed hexyl acid phosphate
plus di (Cl l-C 14) branched aLkyl ~mines (as rust inhibitor/anti wear agents). A
more complete listing of other FDA approved materials suitable for use as anti-
oxidants, rust prolecli-/e compounds and anti-wear additives appears in 21 CFR
178.3570.
It is highly desirable that lubncating compositions used in can
se~ming and other related food processing equipment meet a number of
performance specifications, including a flash point of 200C mil~;",l~ a
viscosity at 40C preferably in the range 140-160, a viscosity index of 95
...., dispersency/emulsibility under the ASTM D1401 2 minute mix test
80C expressed as oiVwater/emulsion (time) of 0-20-60 (60) based on 80 unit,
m~X;~ There must also be no rust observable on the spindle under the
ASTM D665B test using synthetic salt water and the oxidation stability, as
del~ ....i.~ed by the Rotary Bomb Oxidation Test should be 75 minute minimum.
The can seamer lubricant should be both FDA acceptable for food plants and
have USDA H- 1 approval.
The lubricating composition of the present invention meets all
these criterion.
The invention is fi~er elucidated in ~e following non-limiting
examples and comparisons.
EXAMPLES
EXAMPLE 1
A can seamer lubricant was form~ ted comprising 88.6 wt% USP
mineral oil 600 (white oil), 9 wt% of polyisobutylene thickener (average
molecular weight about 1340), 2 wt% tetraglyceryl mono-oleate (emlll.cifier),
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0.2 wt% of a salt of mixed hexyl acid phosphate and di (Cl l-C14) branched
alkyl ~mines (rust inhibitor/anti wear agents) and 0.2 wt% food grade BHT anti
oxidant. This form~ tion possessed a flash point of greater than 200C, a
viscosity at 40C of 150 cSt, a viscosity index of 145, D1401, 2 minute mix
emulsion characteristics, reported as oil-water-emulsion (time) test run at 80Cof 0-15-65 (60). It passed the ASTM D665A and ASTM D665B rust tests, the
Falex Wear ASTM D2870 (modified) wear test and the Rotary Bomb oxidation
test with a le-~ing of 75 .,.;n~les
This lubricant has very good water emlll~ifying and dispersing
plop~lies and oxidation resistance, similar to the aviation oils cu~lenlly used as
can se~llcl lubricants but superior rust and wear protection than the aviation oils,
e.g., Shell's Aeroshell W oils and Exxon Aviation EE oils, both of which failed
both the ASTM D665A and the ASTM D665B (using synthetic salt water) Rust
Tests and the ASTM D2670 (modified) Falex Wear test when tested under the
same conditions as the present formulation. More importantly, the formulation
of the present invention is ~re~ared using FDA approved components and
therefore is FDA acceptable for food plant and USDA H-l approvable.
COMPARATIVE EXAMPLE 1
A number of other esters and acids were evaluated as water
lom~ ifying/dispersing agents in comparison to poly glyceryl mono oleate.
These ester and acids are recited below, with a comment on the observed
perform~ ces These materials were not tested in a fully form~ ted lubricant
but only in combination with USP mineral oil base stock. The additives were
evaluated at treat rate of 2%, then 1% unless otherwise indicated. A single
observation comment is provided for all concentrations tested.
Sorbitan mono-oleate - treat rates 2 to 4% - additive did eml11~ify water to
some degree but only to half as much as aviation oils. Left droplets of oil
tbat conden~ed after time to sep~ale and drop out. Yellow color deemed
lln~cceptable.
Polyoxyethylene (20) sorbitan mono-laurate-oil-insoluble, haze.
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Polye~ylene (4) sorbitan mono-laurate-oil-insoluble, haze.
Polyoxyethylene (20) sorbitan monopolmilite-oil-insoluble, haze.
Polyoxyethylene (20) sorbitan mono~ le-oil-insoluble, haze.
Polyoxye~ylene (20) sorbitan mono-oleate-yellow color to oil, -oil
insoluble, haze.
Polyoxyethylene (5) sorbitan mono-oleate-yellow color to oil, essentially
oil insoluble, haze.
Polyoxyethylene (20) sorbitan tuoleate - oil insoluble, haze.
Sorbitan trioleate - soluble, not effective as emulsifier/dispersing agent.
Polyoxyethylene sorbitol hexoleate - hazy, additive cryst~lli7e~ as rated -
no effect in water she~ling
Sorbiton monostearate - insoluble.
Glycerol mono~lealale - insoluble.
Phosphated mono and diglycerides-reacted to form sodium salt, insoluble.
Polyethylene glycerol mono-oleate - insoluble.
Olive oil (~80% oleic acid) insoluble.
COMPARATIVE EXAMPLE 2
Glyceryl mono oleate at a number of di~le,~l treat levels was
evaluated for em~ ification/dispersing performance and co"l~ed with aviation
oils (Shell Aeroshell W100 and Exxon Aviation EE) as well as Atmos 300 (a
blend of mono and diglycerides and propylene glycol), and polyglyceryl (4)
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mono oleates. The test was ASTM D1401 modified to two ~ les mixin~ time.
The results are presented below.
Oil / Water / Fmllleion
1%glycerylmono oleate * 2 0 78
2% glyceryl mono oleate * 3 0 77
5% glyceryl mono oleate * 2 0 78
2% polyglyceryl (4) mono oleate 0 15 65
2% Atmos 300 13 6 61
Shell (Aeroshell Wl00) 0 20 60
Exxon Aviation EE 0 13 67
* oil portion appeared clear upon blending but glyceryl mono-oleate
came out of solu~ion after 48 hours.
In separate runs 0.5% glyceryl mono oleate was tried but it came
out of solution after 48 hours. Polyglyceryl (4) mono oleate was found to be
soluble at up to 5% loading after 240 hours.
It was unexpected that polyglyceryl mono oleates would have the
right balance of water solubility and oil solubility to match the aviation oils for
.omllleibility/dispersancy. The polyglyceryl mono oleate is approved for use by
FDA (para. 21 CFR 178.354) and should be USDA H-l approvable.
