Note: Descriptions are shown in the official language in which they were submitted.
1 3L 73~
- 1 - C.586 (R)
This inYention relates to a lubricant com~osition especially
adapted for use as conveyor belt lubricant.
The majorlty of modern bottle filling and capping machines in
S food and other industries are equipped with slat or chain belt
conveyors for transporting the bottles to and from the machines.
Dur;ng operation an aqueQus lubricating solution is sprayed via
jet nozzles onto the moving conveyor belt to ef~ect smooth trans-
port of the bottles and cleaning of the chain belt.
The traditional type of formulation for conveyor belt lubricants
is based on fatty acid soap solutions, with or without other
additives, such as sequestrants, surfactants, solvents, etc.
Although soap itself is a very good lubricant, it suffers from
probtems of excessive foaming in soft water, or of calcium soap
preeipitation in hard water, which ~ay cause blockages in the
automatic lubricant syste~s, espec~ally in the nozzles. Zn order
to reduce this blocking tendency, high amounts of sequestrants
have been used to soften the water, but under these conditions
such formulations would aga;n suffer from excessive foaming.
In hard water the use concentration of a lubricant containing a se-
questrant, which is needed to prevent the blockage of nozzles, is
determined by the water hardness. This often results in ~uch higher
concentrations of the lubricant being used than is necessary
for adequate lubricity. However, a high concentration for this
traditional type of formulation inevitably causes excessive
foaming under these conditions.
In practice, foam can be a problem in three ways:
(i) It falls off the conveyor onto the floor benea~h and builds
up into an unsightly '~ountain' of suds.
(ii) It climbs up the bottles when they are held stationary on a
moving conveyor. If the bottles are labelled, the label will
be moistened by the foam and become more susceptible to
physical damage. Even if this does not happen, it may cause
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1 ~73~ ~
- 2 - C 586 ~R)
staining of the label after the foam has collapsed.
(iii) Foam on the bottom of washed bottles can cause problems
with automatic bottle scanners.
Blackening of conveyor belts is another problem with poor lubri-
cants. This could occur if clean bottles were held stationary
on an initially clean conveyor lubricated with an inadequate
product, It may also occur if soil, e.g. milk spillage, in the
vicinity of bottle fillerst is not adequately emuls;fied or
dispersed by the lubricant.
Hence, good lubricating ability, low foaming, insensitivity to
water hardness, good cleaning efficiency and no tendency to
blocking are essential properties for a good conveyor belt lu^
bricant.
A further equally important requirement is that it should work
under acid conditions. This is important, for example, in soft
-- drinks bottling plants, where many products are acidic and will
inevitably contaminate the conveyor, particularly in the vicinity
of the bottle fillers.
The attainment of all these combined properties in conveyor lu-
-br;cant compositions is a matter of difficult formulation.
- 25
Built soap ~or~lulations which exhibit good lubricity and satis
factory hard water tolerance are genera~ly unsatisfa~tor~ owing
to their tendency to excessive foaming. Many mdter;als which might
be expected to defoam cold soap solutions were quite disappoint-
ing on examination and cannot be used. Moreover, the dif~icultand complex formulation needed to achieve the necessary require-
ments ~or a good conveyor lubr;cant tend to m~ke the product
rather expensiVe.
The present invention now provides an improved lubricant composi-
tion suitable for use as a conveyor belt lubr~cant based on a
. simple and~ cost-effectlve formulation.
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~ 3 ~ C 586 (R)
The lubricant composition of the invention is substantially freefrom a fatty acid soap and comprises:
(a) a carboxylated nonion;c of thè general formula:
R-~~~CH2)m~ n~CM
wherein R ls a saturated or unsaturated C14-C20 alkyl group;
m = 2-3; n = 3-7 and M is H, an alkali metal or alkanolamine
cation; ;
(b~ an acyl sarcosinate of the general formula:
/~
R-C -~-CH2-COOM
CH3
wherein R is a Cll-C19 alkyl or alkylene group; and ~ is H,
an alkali metal or alkanolamine cation; and
(c) water.
Generally the carboxylated nonionic and acyl sarcosinate mixture
in the composition of the invention is neutralized to g;ve a pro-
duct pH of between i and 11, preferably between 8 and 9, particu-
larly about 8.5. Alkali hydroxides, such as sodium hydroxide and
potass;um hydroxide, or alkanolamines, such as monoethanolamine
or diethanolamine , are examples of suitable neutralizing agents.
Advantageously, the weight ratio of çarboxylated nonionic to acyl
sarcosinate in the composition of the invention is from about 2:1
to 1:2. A preferred ratio is 3:2, which will give a product suit-
able for use in a w;de range of water hardnessl i.e. from 7ero to
3 mol m 3.
The degree of alkoxylation (n) in the carboxylated nonionic mole-
cule is important. A lower degree of ethoxylation causes an impro-
vement in lubric~ty and a further reduction ln foam, but at the
expense of the composition becoming more sensitive to hard water.
The degree of ethoxylation therefore should not be tower than 3.
A higher degree of ethoxylation causes a reduction 1n lubricity
and an increase in foam. The degree of ethoxylation therefore
should not be higher than 7.
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1 1 738.?,1
- 4 - C 586 ~R)
A preferred carboxylated nonionic is:
C18H35-[0-CH2-cH2~5 COOM.
A preferred acyl sarcosinate is oleyt sarcosinate having the
formula: O
C17H33C -N-CH2-cOoM
CH3.
Apart from the components already mentioned, it may be desirable
to also include in the lubricant composition of the invention
a conventional nonionic surfactant compound, particularly a
low-foaming nonionic surfactant. The incorporation thereof will
have the effect of improved detergency, which can be of import-
ance, e.g. in dairies.
Examples of su;table nonionic surfactants which may be used in-
clude in particular the liquid reaction products of ethylene
oxide with C6-C12 alkyl phenols or with aliphatic ~C8-C1~) pri-
mary or secondary linear or branched chain alcohols, and products
made by condensation of ethylene oxide with propylene oxide or
the reaction products of propylene oxide and ethylene diamine.
Other so-called nonionic surfactants include long chain tertiary
amine oxides and long chain tertiary phosphine oxide. Nonionics
having an HLB value of from 10-12, preferably from 10.5-11, are
particularly suitable, such as nonyl phenol condensed with ~-6
ethylene oxide groups (NP/5-6 EO).
Though any ~orm would be possible, the lubricant compositions of
the invention are preferably presented in liquid form. These li-
quids will generally comprise about 5-20~ by weight of the active
components (a) and (b), i.e. carboxylated nonionic and acyl sarco-
s;nate, together. Higher active mixture contents may be presented
as viscous liquid or paste~like products.
In use the composition of the invention is normally diluted with
water to an active concentrat;on of about 150-750 mg/liter. In li-
quid composition terms a dilution of from about 0.1-0.5% is nor-
mally applied.
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- 5 - C 586 ~R)
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The following composition was_prepared and tested against two
commercial products, Jetloob~ex J.R. Grace and Zefa ~ Super H
ex Lever Industrial.
~position 1 ~0 by weight
Akypo~ R050 (carboxylated nonionic) 9
Hamposyl ~ O (acyl s~rcosinate) 6
KOH 1.6
Water 83.4
iS C18H35- [~CH2~cH2]5 -COO~ ex Chem-y
Hamposyl ~ O is C17H33C~ -I-CH2-COOH ex W.R. Grace.
CH3
The Composition 1 of the invention and the commercial products
~ere tested at various use concentrations and diluted with water
of various degrees of hardness, for frictional drag ~measure of
lubricity), solution appearance and foam.
~ ~he results are illustrated in the following Table.
Table of Resu~ts
Test Product Use Conc. Water Fric- Solution Foam
Hardness tional Appear-
-3 Drag ance
_ (mol m 3 (kg)*
_
aJetloob 0~33 1 2slightly) ~/+
turbid )
b do. 0.25 1 3 turbid O
c do. 0.20 1 4 do.
d do. 0.25 O 1.5clear +~
e do. 0.20 0.5 1Sltu9hrblYd O
f Zefd 0.33 1 1 turbid
9 do. 0.25 1 4 do.
h do. 0.33 O 1.5clear .
_ ~ __ _~ ~ _._
i I 0.33 O 1.5clear 0/~
k I 0.25 O 1.75 clear O
l I 0.33 3 1 clear -/o
11~3~
- 6 - C.5~6 ~R)
The drag was measured on 12 half filled one-litre milk
bottles which were held stationary on a moving slat con-
veyor
~oam code ++ excessive
~ acceptable
0 moderate
- slight
~-- none
The hardest water used in the tests with the commercial products
was actually still relatively soft. Despite this, none of the
products gave clear solutions when diluted to a concentration
of 0.33% or less with it. The turbid;~y was due to calci~m soap
formation which would invariably cause jet nozzle blocking
problems.
The tests a-e show that if "Jetloob" is d;luted to a concentra-
tion of less than 0.33% in water of 1 mol m 3 hardness, lubric-
ity will be only mediocre. That this was due to the hardness
; salts in the water rather than the low concentration is shown
by the fact that 0.2% solution in 0.5 mol m 3 hard water gives
good lubricity (cf. test e).
Both ~etloob and Zefa gave clear solutions in totally soft
water (tests d and h). They would not cause jet blocking prob-
lems and could be used at low concentrations; unfortunately,
however, thPy both foam excessively and therefore are unsuit-
able.
The Composition I of the invention was clearly superior to
both comnlercial produets ~etloob and Zefa in both hard and
soft water.
Example II
The Composition I of Example I was also tested over a two-week
period at various use concentrations in a problem area (relative-
Iy tall bottles with narrow bases). No problems were encountered
at use concentrations down to 0.2% in soft water. The conveyors
werè noticeably cleaner with this product than with the soap-
, .. . ... .. . ...
based products of the art.
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11 ~ 3 ~ ~ 1 C 586 ~R)
Examples III - YI
The follow;ng examples are further illustrative lubricant compo-
sitions w;thin the invention:
Composition III IV V VI
C18H35- ~0-CH2-CH2~ 5-COOH 4.5 6.0 3.0 3.0
C17H33CON ~CH3]CH2COOH 3.0 9.0 12.0 12.0
KQH 1.0 1.5 1.6
Water 85.5 83.5 83.4 85.0
Nonyl phenol/5-6 ethylene oxide 6.0 _
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The compositions IV - V are usable for soft water.
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