U.S. patent application number 13/002708 was filed with the patent office on 2011-06-09 for grease composition.
Invention is credited to Takahiro Ozaki, Keiji Tanaka.
Application Number | 20110136709 13/002708 |
Document ID | / |
Family ID | 40911585 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110136709 |
Kind Code |
A1 |
Tanaka; Keiji ; et
al. |
June 9, 2011 |
GREASE COMPOSITION
Abstract
Grease composition for use in resin lubrication incorporating
into a grease base material which includes a base oil and a fatty
acid metal salt thickener at least one saturated or unsaturated
fatty acid having from 8 to 22 carbon atoms and/or fatty acid metal
salt, being a metal salt of a linear saturated fatty acid having
from 8 to 14 carbon atoms or a metal salt of an unsaturated fatty
acid having from 16 to 22 carbon atoms and from 1 to 4 unsaturated
groups, the metal having a valence of from 1 to 4 excluding fatty
acid metal salts used for the thickener. The grease composition of
the present invention gives satisfactory lubrication properties
between resin and resin or resin and other material such as a
metal.
Inventors: |
Tanaka; Keiji; (Kanagawa,
JP) ; Ozaki; Takahiro; (Kanagawa, JP) |
Family ID: |
40911585 |
Appl. No.: |
13/002708 |
Filed: |
July 6, 2009 |
PCT Filed: |
July 6, 2009 |
PCT NO: |
PCT/EP2009/058512 |
371 Date: |
February 16, 2011 |
Current U.S.
Class: |
508/144 ;
508/162; 508/539 |
Current CPC
Class: |
C10M 129/40 20130101;
C10N 2020/069 20200501; C10N 2020/065 20200501; C10M 2205/0285
20130101; C10M 2207/1206 20130101; C10N 2040/04 20130101; C10M
2201/1036 20130101; C10N 2040/02 20130101; C10N 2020/067 20200501;
C10M 2215/1026 20130101; C10M 2203/1006 20130101; C10N 2050/10
20130101; C10M 2207/126 20130101; C10N 2040/06 20130101; C10M
169/06 20130101; C10N 2030/06 20130101; C10M 2203/1006 20130101;
C10N 2020/02 20130101; C10M 2203/1006 20130101; C10N 2020/02
20130101 |
Class at
Publication: |
508/144 ;
508/539; 508/162 |
International
Class: |
C10M 117/02 20060101
C10M117/02; C10M 113/10 20060101 C10M113/10; C10M 113/08 20060101
C10M113/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 7, 2008 |
JP |
2008-176945 |
Aug 29, 2008 |
JP |
2008-222113 |
Claims
1. A grease composition for use in resin lubrication, wherein the
grease composition comprises: a grease base material, which
includes a base oil and a fatty acid metal salt thickener, and an
additive of at least one saturated or unsaturated fatty acid having
from 8 to 22 carbon atoms and/or fatty acid metal salt, being a
metal salt of a linear saturated fatty acid having from 8 to 14
carbon atoms or a metal salt of an unsaturated fatty acid having
from 16 to 22 carbon atoms and from 1 to 4 unsaturated groups, the
metal having a valence of from 1 to 4 excluding fatty acid metal
salts used for the thickener.
2. The grease composition for use in resin lubrication according to
claim 1, wherein the metal of the aforementioned fatty acid metal
salt is lithium, sodium, potassium, magnesium, calcium, zinc,
aluminium or lead.
3. The grease composition for use in resin lubrication according to
claim 1, wherein the total content of the one or more saturated or
unsaturated fatty acid and/or fatty acid metal salt is in the range
of from 0.1 to 10% by mass relative to the total amount of the
grease composition.
4. The grease composition for use in resin lubrication according to
claim 1, wherein at least one of a urea, bentonite, calcium
phosphate or sodium terephthalamate is incorporated as a thickener
together with the aforementioned fatty acid metal salt thickener.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates to a grease composition for use in
resin lubrication which is used at lubrication points where rolling
or sliding occur when resin materials are employed.
BACKGROUND OF THE INVENTION
[0002] In recent years, the use of resin materials for components
in various industrial machines, not least in the automotive
industry, has become prominent from many points of view, such as
lighter weight, lower cost, lower friction, or recycling. But as
the structural elements of the components have diversified, many
new problems have emerged, and all sorts of technologies are being
improved.
[0003] For example, in the movable parts of electric door mirrors
or the sliding parts of telescopic shafts in car steering, the
various sliding parts of R&P steering rack guides, the power
transmission gears of electric power steering devices, the internal
sliding parts of various actuators and air cylinders, linear guides
and ball screw retainers in machine tools, various bearing
retainers, the sliding parts of crane booms, and also the resin
gear parts in audio machines such as radio cassette players,
videotape recorders and CD players, the resin gear parts in office
automation equipment such as printers, photocopiers and faxes, and
the sliding parts in various electrical switches, there are
lubrication points where resin and resin or resin and a material
other than resin such as a metal function by coming into a state of
contact.
[0004] Hitherto, in the field of lubrication almost all the
structural elements of machines were of metallic materials, and so
the history of research into friction and wear of metal against
metal such as iron, aluminium, alloys thereof, brass and bronze is
old and vast, and many techniques have been accumulated through
this profound experience and knowledge.
[0005] For example, it is known that extreme pressure agents and
anti-wear agents which contain elements such as phosphorus or
sulphur are effective against the friction and wear of metal
against metal, and that these additives form a film which
proactively causes a chemical reaction with the metallic surface,
thereby exhibiting the functions of reducing friction and wear and
preventing machinery from seizing up. This technology is widely
used in engine oils and gear oils and in high-performance
industrial lubricating oils and greases.
[0006] However, despite the fact that the history of the technology
of lubrication of resins against resins, or resins against
different materials such as metals, is brief, as mentioned above
their applications have broadened in recent years, but the present
situation is that in the course of this diversification no
technology has been presented that is able thoroughly to satisfy
the various requirements imposed on lubricating greases.
[0007] For example, in the case where technology using phosphorus
or sulphur additives effective against friction or wear in the
aforementioned metal-to-metal cases is applied to lubrication
points of resins and metallic materials, virtually no friction
reduction effect such as can be obtained for metal-to-metal is
obtained. In fact there are by no means a few instances where the
friction and anti-wear performance deteriorates and the life of the
machine component is shortened.
[0008] This is thought to be because the chemical activity of the
surfaces is much weaker in the case of resins than for metals, and
there is virtually no reaction at the rubbing surfaces with organic
additives such as those based on phosphorus or sulphur, and given
that adsorption is also weak, the effect in regard to friction and
wear is paltry, and accordingly the friction reducing effect is
weak. Also, in cases where they are used at boundaries where
temperature rises are deliberately effected, the active sulphur and
phosphorus in these additives permeate into the resin components
and cause cracks and brittleness. There are also cases where the
contrary actions of friction and wear are promoted.
[0009] In order to improve the lubrication state of the
aforementioned resins against resins or resins against different
materials such as metals, a grease has been proposed (Japanese
Patent H6-43594 (1994)) for use in plastics lubrication which
contains in a lithium grease a mixture of alkylene oxide-polyhydric
alcohol addition polymerisation oligomers and chained hydrocarbon
oligomers, with a quaternary ammonium salt-containing clay mineral
with a dispersant. Also, a technology has been disclosed (Japanese
Laid-open Patent 2005-54024) for a grease composition for use in
resin lubrication which contains a non-polar wax or polar wax along
with a base oil such as a poly-.alpha.-olefin oil, a mineral oil or
a highly refined mineral oil and a metallic soap or metallic
complex soap thickener. Further improvements are anticipated.
[0010] This invention is an attempt to obtain a grease composition
for use in resin lubrication wherein friction is attenuated and
satisfactory lubrication performance is obtained at lubrication
points where rolling and sliding and so on occur where at least one
side of a paired structure, such as resin against resin or resin
against a different material such as a metal, is comprised of a
resinous material.
[0011] Having undertaken research and investigations on the basis
of the theory of surface chemistry into the lubrication behaviour
of resins in the past, the inventors have arrived at this invention
by discovering that the extremely weak electrical charge that
occurs at the surface of a resin and a paired material, such as
resin against resin or resin against a different material such as a
metal, interacts with certain saturated or unsaturated fatty acids
and fatty acid metal salts which are added to greases, and further
that these additives exhibit a binder function with the grease so
that it is possible to form and maintain more reliably a
lubrication film on the surface of the resin and resin or paired
material, with the result that friction is reduced and satisfactory
lubrication is obtained.
SUMMARY OF THE INVENTION
[0012] This invention is for a grease composition for use in resin
lubrication incorporating into a grease base material which
includes a base oil and a fatty acid metal salt thickener at least
one saturated or unsaturated fatty acid having from 8 to 22 carbon
atoms and/or fatty acid metal salt, being a metal salt of a linear
saturated fatty acid having from 8 to 14 carbon atoms or a metal
salt of an unsaturated fatty acid having from 16 to 22 carbon atoms
and from 1 to 4 unsaturated groups, the metal having a valence of
from 1 to 4 (excluding fatty acid metal salts used for the
thickener).
[0013] The metals of the fatty acid metal salts include metals such
as lithium, sodium, potassium, magnesium, calcium, zinc, aluminium
and lead.
[0014] It is preferred that the total amount of saturated or
unsaturated fatty acid and/or fatty acid metal salt used is in the
order of from 0.1 to 10% by mass. Further, it is possible to use,
together with the fatty acid metal salt thickener, other kinds of
thickener such as a urea, bentonite, calcium phosphate or sodium
terephthalamate, singly or in mixtures.
[0015] According to this invention friction is attenuated so that
it is possible to obtain satisfactory lubrication performance at
lubrication points such as rolling and sliding points between parts
comprising resinous materials one against another, and it is
possible to use it over a wide range as a grease composition for
use in resin lubrication.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The base oil in this invention is one which may ordinarily
be used as the base oil of a lubricating oil or as the base oil of
a grease, and there are no special restrictions. As examples
mention may be made of mineral oils, synthetic oils, animal and
plant oils, and mixtures thereof.
[0017] In particular it is possible to use, singly or as mixtures,
base oils which belong to Group I, Group II, Group III, Group IV
and so on of the API (American Petroleum Institute) base oil
categories.
[0018] Group I base oils include, for example, paraffinic mineral
oils obtained by a suitable combination of refining processes such
as solvent refining, hydrorefining, and dewaxing in respect of
lubricating oil fractions obtained by atmospheric distillation of
crude oil.
[0019] Group II base oils include, for example, paraffinic mineral
oils obtained by a suitable combination of refining processes such
as hydrorefining and dewaxing in respect of lubricating oil
fractions obtained by atmospheric distillation of crude oil. Group
II base oils refined by hydrorefining methods such as the Gulf
Company method have a total sulphur content of less than 10 ppm and
an aromatic content of not more than 5% and so are suitable for
this invention.
[0020] Group III base oils and Group II+ base oils include
paraffinic mineral oils manufactured by a high degree of
hydrorefining in respect of lubricating oil fractions obtained by
atmospheric distillation of crude oil, base oils refined by the
Isodewax process which dewaxes and substitutes the wax produced by
the dewaxing process with isoparaffins, and base oils refined by
the Mobil wax isomerisation process. These too are suitable for use
in this invention.
[0021] Concrete examples of synthetic oils include polyolefins,
polyoxyalkylene glycols such as polyethylene glycol or
polypropylene glycol, esters such as di-2-ethylhexyl sebacate or
di-2-ethylhexyl adipate, polyol esters such as trimethylolpropane
esters or pentaerythritol esters, perfluoroalkyl ethers, silicone
oils, polyphenyl ethers, and so on.
[0022] The aforementioned polyolefins include polymers of various
olefins or hydrides thereof. Any olefin may be used, and as
examples mention may be made of ethylene, propylene, butene and
.alpha.-olefins with five or more carbons. In the manufacture of
polyolefins, one of the aforementioned olefins may be used singly
or two or more may be used in combination. Particularly suitable
are the polyolefins called poly-.alpha.-olefins (PAO). These are
base oils of Group IV.
[0023] GTL (gas to liquid) base oils synthesised by the
Fischer-Tropsch method of converting natural gas to liquid fuel
have a very low sulphur content and aromatic content compared with
mineral oil base oils refined from crude oil and have a very high
paraffin constituent ratio, and so have excellent oxidative
stability, and because they also have extremely small evaporation
losses, they are suitable as base oils for this invention.
[0024] As typical examples of animal and plant oils mention may be
made of castor oil and rape-seed oil.
[0025] The various aforementioned oils may be used singly or in
mixtures for the base oil. The aforementioned examples are listed
singly but the invention is not limited thereby.
[0026] The thickener in this invention uses fatty acid metal salts.
These fatty acid metal salts are those in which the fatty acid and
metal are bonded, and they are normally called metallic soaps. As
illustrative examples mention may be made of lithium soaps, sodium
soaps, potassium soaps, magnesium soaps, calcium soaps, barium
soaps, aluminium soaps, zinc soaps, lead soaps and complex soaps
therefrom. These may be used singly or in mixtures thereof.
[0027] In specific cases it is also possible as appropriate to use
in combination, apart from the fatty acid metal salt thickener,
other thickeners such as bentonite, clay, silica, tricalcium
phosphate, calcium sulphonate complexes, ureas and sodium
terephthalamate.
[0028] The additive added to the grease base material which
incorporates the aforementioned base oil and thickener is a
saturated or unsaturated fatty acid having from 8 to 22 carbon
atoms and/or a fatty acid metal salt being a metal salt of a linear
saturated fatty acid having from 8 to 14 carbon atoms or a metal
salt of an unsaturated fatty acid having from 16 to 22 carbon atoms
and from 1 to 4 unsaturated groups, the metal having a valence of
from 1 to 4 (excluding fatty acid metal salts used for the
thickener).
[0029] As examples of fatty acids forming the starting material of
the aforementioned saturated or unsaturated fatty acids and fatty
acid metal salts in this invention, mention may be made of caprylic
acid, pelargonic acid, capric acid, lauric acid, linderic acid,
myristic acid, tsuzuic acid, physetoleic acid, myristoleic acid,
pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid,
stearic acid, 12-hydroxystearic acid, petroselinic acid, oleic
acid, elaidic acid, vaccenic acid, linolic acid, linolenic acid,
elaeostearic acid, tuberculostearic acid, arachidic acid,
eicosadienic acid, eicosatrienic acid, arachidonic acid, behenic
acid, lignoceric acid, nervonic acid, hexadocosanic acid,
octadocosanic acid and erucic acid.
[0030] The saturated or unsaturated fatty acids in this invention
are preferably those having from 8 to 22 carbon atoms, and in the
case of fatty acid metal salts are preferably linear saturated
fatty acid salts having from 8 to 14 carbon atoms or unsaturated
fatty acid metal salts having from 16 to 22 carbon atoms.
[0031] If the metals in the fatty acid metal salts of this
invention are lithium, sodium, potassium, magnesium, calcium, zinc,
aluminium, lead and so on, the effect of reducing the frictional
force between materials at the lubrication points between the resin
and material other than resin is large, and these metals and fatty
acids can be reacted easily. The fatty acid salts are also stable
chemically and are easy to maintain in the preferred lubrication
state.
[0032] As to the total amount of the saturated or unsaturated fatty
acids or the one or more fatty acid metal salts, it is best to add
these in an amount in the range of from 0.1 to 10% relative to the
total amount of the grease composition, and preferably they should
be used in the range of from 1 to 5% by mass. If they are present
in an amount of less than 0.1% by mass, the electrochemical action
on the surface is too small, and the effect of reducing the
friction coefficient is too low. If they are present in an amount
of greater than 10% by mass, it becomes difficult to demonstrate
the basic performance of the grease composition (for example,
viscoelasticity, shear stability, heat resistance and so on)
effectively, and it is likely that it will become difficult to
maintain a stable state over the long term. Costs also rise.
[0033] Also, it is possible to add as appropriate to the grease
composition of this invention anti-oxidants, rust preventatives,
oiliness agents, extreme pressure additives, anti-wear agents,
solid lubricants, metal deactivators, polymers and other
additives.
[0034] The anti-oxidants include, for example,
2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-paracresol,
P,P'-dioctyldiphenylamine, N-phenyl-.alpha.-naphthylamine,
phenothiazines and so on.
[0035] The rust preventatives include paraffin oxide, carboxylic
acid metal salts, sulphonic acid metal salts, carboxylic acid
esters, sulphonic acid esters, salicylic acid esters, succinic acid
esters, sorbitan esters and various amine salts.
[0036] The oiliness agents, extreme pressure additives and
anti-wear agents include, for example, sulphurised zinc dialkyl
dithiophosphates, sulphurised zinc diaryl dithiophosphates,
sulphurised zinc dialkyl dithiocarbamates, sulphurised zinc diaryl
dithiocarbamates, sulphurised molybdenum dialkyl dithiophosphates,
sulphurised molybdenum diaryl dithiophosphates, sulphurised
molybdenum dialkyl dithiocarbamates, sulphurised molybdenum diaryl
dithiocarbamates, organic molybdenum complexes, sulphurised
olefins, triphenylphosphates, triphenylphosphorothionates,
tricresylphosphates, other phosphate esters and sulphurised fats
and oils.
[0037] The solid lubricants include, for example, molybdenum
disulphide, graphite, boron nitride, melamine cyanurate, PTFE
(polytetrafluoroethylene), tungsten disulphide, mica, graphite
fluoride and so on.
[0038] The metal deactivators include
N,N'-disalicylidene-1,2-diaminopropane, benzotriazole,
benzoimidazole, benzothiazole, thiadiazole and so on.
[0039] Since, in this invention, it is possible to reduce friction
and obtain satisfactory performance at lubrication points where
rolling and sliding are evident between materials where one of the
pair of materials is constituted of resin, one of the paired
materials must be a resin, but the part which pairs with this resin
can be, in addition to a resin, not only various metallic materials
such as iron, copper, aluminium or other metal, or alloys, thereof,
but also rubber and glass, or non-polar materials such as ceramics,
and so it can be widely used with no special restrictions.
[0040] Also, it is possible to any use ordinary plastic or
engineering plastic for the aforementioned resin materials, and as
examples mention may be made of polyamides, polyacetals,
polycarbonates, polyethylene terephthalates, polybutylene
terephthalates, polybutylene naphthalates, polyphenylene ethers,
polyphenylene sulphide, fluorinated resins, polyacrylates,
polyamidimides, polyether imides, polyether ether ketones,
polysulphones, polyether sulphones, polyimides, polystyrenes,
polyethylenes, polypropylenes, phenol resins, AS resins, ABS
resins, AES resins, AAS resins, ACS resins, MBS resins, polyvinyl
chloride resins, epoxy resins, diallyl phthalate resins, polyester
resins, methacryl resins, and ABS/polycarbonate alloys, but they
are not limited to these.
EXAMPLES
[0041] The invention is explained in detail below by means of
examples and comparative examples, but the invention is in no way
limited by these examples.
[0042] The following materials were prepared for the examples and
comparative examples.
1. Base oil A: a mineral oil with kinematic viscosity at 40.degree.
C. of 101.1 mm.sup.2/s. 2. Base oil B: a poly-.alpha.-olefin oil
with kinematic viscosity at 40.degree. C. of 31.2 mm.sup.2/s. 3.
Base oil C: a highly refined oil with kinematic viscosity at
40.degree. C. of 47.08 mm.sup.2/s, viscosity index of 146, % CA of
less than 1, % CN of 11.9, and % CP of not less than 85. 4.
Thickener A: lithium 12-hydroxystearate soap obtained by a reaction
of 12-hydroxystearic acid and lithium hydroxide in the base oil. 5.
Thickener B: a diurea obtained by a synthesis reaction of 2 mol of
octylamine and 1 mol of MDI (4,4'-diphenylmethanediisocyanate) in
the base oil. 6. Thickener C: bentonite obtained by gelation after
swelling bentonite with an organic solvent in a base oil. 7.
Thickener D: sodium terephthalamate obtained by reaction of methyl
N-octadecyl terephthalamate and sodium hydroxide in the base oil.
8. Thickener E: obtained by gelation after swelling an
hydroxyapatite/tricalcium phosphate composite as expressed by
[Ca.sub.3(PO.sub.4).sub.2].sub.3.Ca(OH).sub.2 with an organic
solvent.
[0043] The greases were prepared in a kettle using the base oils
and thickener in the proportions shown for Examples 1 to 13 in
Tables 1 to 3, and the grease compositions were obtained by adding
the various fatty acids and/or fatty acid metal salts.
[0044] In specific detail, in the case of the greases which used
thickener A (a lithium soap) in Examples 1 to 8, the base oil,
thickener and the various fatty acids or fatty acid metal salts
which are the additives were first weighed out in the proportions
shown in Tables 1 to 2 so that the total amount of the grease
composition would be 1000 g. Then, the base oil and the
12-hydroxystearic acid and lithium hydroxide with a small amount of
water were pasted into a kettle of capacity 3 kg specially used for
preparation of greases. After sealing, while heating and stirring,
a saponification reaction was effected, and the pressure was raised
to 0.35 MPa at approximately 150.degree. C. Then the water was
gradually removed, and the contents were dissolved by further
heating to 215.degree. C. Cooling was then effected at a fixed
rate, and once the soap fibres had been allowed to grow, the
aforementioned additives, the fatty acids or fatty acid metal
salts, were pasted in and, after a homogeniser treatment, the
grease compositions for use in resin lubrication for each of
Examples 1 to 8 were obtained.
[0045] The fatty acid metals salts specified in Tables 1 to 3 were
used as obtained by first reacting the fatty acids and metals in
accordance with the molar ratios specified in Tables 1 to 3 (and
similarly also for the comparative examples of Table 4 below).
[0046] In the case of the greases which used other thickeners B to
E together with thickener A (a lithium soap) in Examples 9 to 13 of
Tables 2 and 3, the greases made as described below using
thickeners B to E were specially prepared, and were mixed in a
kettle specially used for preparation of greases at room
temperature in the proportions shown for the thickeners in Tables 2
and 3. The various fatty acids and fatty acid metal salts were
pasted in and, after a homogeniser treatment, the grease
compositions for use in resin lubrication for each of Examples 9 to
13 were obtained.
[0047] In the case of the greases which used thickener B (a urea),
the base oil, thickener B and the various fatty acids or fatty acid
metal salts which are the additives were first weighed out in the
proportions shown in Tables 2 and 3 so that the total amount of the
grease composition would be 1000 g. Then part of the base oil and
the MDI (4,4'-diphenylmethanediisocyanate) which was the raw
material for thickener B were pasted into a kettle of capacity 3 kg
specially used for preparation of greases. While heating and
stirring, the temperature was raised to 60.degree. C., and a
reaction was effected by folding in octylamine already dissolved
and mixed in the remaining part of the base oil. The temperature
was further raised to 180.degree. C., cooling was then effected at
a fixed rate, and the aforementioned various fatty acids or fatty
acid metal salts were pasted in and, after a homogeniser treatment,
the grease compositions were obtained.
[0048] In the case of the greases which used thickener C (a
bentonite), the base oil, thickener C and the various fatty acids
or fatty acid metal salts which are the additives were first
weighed out in the proportions shown in Table 3 so that the total
amount of the grease composition would be 1000 g. Then the base
oil, the bentonite of thickener C and an organic solvent to promote
gelation were pasted into a kettle of capacity 3 kg specially used
for preparation of greases. While heating and stirring, the
temperature was gradually raised to 150.degree. C. so that the
organic solvent was made sufficiently volatile to effect uniform
diffusion and swelling. Cooling was then effected at a fixed rate,
and the aforementioned various fatty acids or fatty acid metal
salts were pasted in and, after a homogeniser treatment, the grease
compositions were obtained.
[0049] In the case of the greases which used thickener D (sodium
terephthalamate), the base oil, thickener D and the various fatty
acids or fatty acid metal salts which are the additives were first
weighed out in the proportions shown in Table 3 so that the total
amount of the grease composition would be 1000 g. Then the base oil
and the methyl N-octadecylterephthalamate which was the raw
material of thickener D were pasted into a kettle of capacity 3 kg
specially used for preparation of greases. While heating and
stirring, a suspension of sodium hydroxide already stirred and
dispered in water was folded into the kettle at a temperature of
90.degree. C., and a reaction was effected while gradually heating
and stirring until the temperature reached 170.degree. C. Cooling
was then effected at a fixed rate, and the aforementioned fatty
acid metal salts were pasted in and, after a homogeniser treatment,
the grease compositions were obtained.
[0050] In the case of the greases which used thickener E (a
tricalcium phosphate), the base oil, thickener E and the various
fatty acids or fatty acid metal salts which are the additives were
first weighed out in the proportions shown in Table 3 so that the
total amount of the grease composition would be 1000 g. Then, the
base oil, the tricalcium phosphate and an organic solvent to
promote gelation were pasted into a kettle of capacity 3 kg
specially used for preparation of greases. While heating and
stirring, the temperature was gradually raised to 150.degree. C. so
that the organic solvent was made sufficiently volatile to effect
uniform diffusion and swelling. Cooling was then effected at a
fixed rate, and the aforementioned fatty acid metal salts were
pasted in and, after a homogeniser treatment, the grease
compositions were obtained.
[0051] For Comparative Examples 1 to 6, the various raw materials
were weighed out in accordance with the proportions shown in Table
4, and grease compositions were prepared by following the method
described for the aforementioned examples.
[0052] The following measurements and tests were carried out in
order to compare the characteristics and performance of the
examples and comparative examples.
1. Penetration: measured in accordance with JIS K2220-7, 2.
Dropping point: measured in accordance with JIS K2220-8. 3.
Kinematic viscosity of base oils: measured in accordance with JIS
K2283. 4. Friction tests: Bowden type friction tests were carried
out. In other words, the friction coefficient between a resin (test
material 1b) and a paired material other than a resin (test
material 1a) was measured under the following test conditions using
a Bowden friction test rig. [0053] (1) Test material 1a:
Material--Copper alloy ALBC2 and steel S45C. [0054] Dimensions--pin
shape of outside diameter 5.0 mm and length 24 mm, the pin tip
being a semi-spheroid of r=2.5 mm, and the contact surface was
machined to a flat area of approximately 1.0 mm diameter. [0055]
(2) Test material 1b: Material--polyacetal resin (Delrin 500P made
by Dupont Ltd.) [0056] and polyamide resin (66 Nylon/Amilan made by
Toray Ltd.) [0057] Dimensions--plate of length 200 mm, width 52 mm.
[0058] (3) Temperature: 25.degree. C. [0059] (4) Sliding rate: 1.0
mm/s [0060] (5) Load: 870 g [0061] (6) Surface pressure of contact
surfaces: 10 MPa
[0062] A Bowden friction test was carried out on all the examples
and on all the comparative examples for a polyamide resin and steel
pairing, and tests were carried out selectively for a polyacetal
resin and copper alloy pairing.
Test Results
[0063] These are as shown in Tables 1 to 4.
Discussion
[0064] The grease compositions for resin lubrication of Examples 1
to 13 all displayed the grease characteristics of a semi-solid and
the penetration displayed moderate hardness values in the range 267
to 290, while the dropping point was also of a satisfactory nature
at not less than 177 to 210.degree. C. Also, the friction
coefficients between a polyamide resin and steel in the Bowden
friction test were 0.060 to 0.069, and the friction coefficients
between a polyacetal resin and copper alloy were uniformly low at
0.062 to 0.066, so that it was evident that a satisfactory
lubrication performance was displayed between various resins and
materials other than resins such as steel and alloys.
[0065] On the other hand, the grease compositions of Comparative
Examples 1 to 6 all displayed the grease characteristics of a
semi-solid, and the penetration displayed hardness values in the
range 265 to 281, while the dropping point was also of a
satisfactory nature at 180 to 207.degree. C., but the friction
coefficients between a polyamide resin and steel in the Bowden
friction test were 0.082 to 0.099, and the friction coefficients
between a polyacetal resin and copper alloy were all high at 0.099
or 0.101, so that it was evident that they were all inferior to the
examples of the present invention as regards the lubrication state
between various resins and materials other than resins such as
alloys or steel, and that no effect in improving lubrication
performance was obtained.
[0066] From these results it can be seen that the grease
composition for resin lubrication of this invention exhibits
satisfactory lubrication performance.
TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 (1) Base oil (mass %)
Lubricating oil A 89.5 89.5 89.5 89.5 89.5 Lubricating oil B -- --
-- -- Lubricating oil C -- -- -- -- -- (2) Thickener (mass %)
Thickener A 8.5 8.5 8.5 8.5 8.5 Thickener B -- -- -- -- --
Thickener C -- -- -- -- -- Thickener D -- -- -- -- -- Thickener E
-- -- -- -- -- (3) Added amount of fatty acid 2.0 2.0 2.0 2.0 0.5
and/or fatty acid metal salt (mass %) Fatty acid (molar ratio)
Caproic acid C6 -- -- -- -- -- Caprylic acid C8 -- -- -- -- --
Lauric acid C12 1 -- -- 2 -- Myristic acid C14 -- -- 2 -- --
Palmitic acid C16 -- -- -- -- -- Behenic acid C22 -- -- -- -- --
Palmitoleic acid C16' -- 1 -- -- -- Oleic acid C18' -- -- -- -- 2
Erucic acid C22' -- -- -- -- -- Linolic aid C18'' -- -- -- -- --
Metal (molar ratio) Magnesium -- -- 1 -- -- Calcium -- -- -- -- --
Zinc -- -- -- 1 -- Aluminium -- -- -- -- 1 Total (1) + (2) + (3)
100.0 100.0 100.0 100.0 100.0 Penetration 278 275 278 277 272
Dropping point .degree. C. 181 177 179 180 179 Kinematic viscosity
of base 101.1 101.1 101.1 101.1 101.1 oil (40.degree. C.,
mm.sup.2/sec) Friction tests (friction coefficient) (1) Polyamide
0.061 0.062 0.068 0.069 0.066 resin-steel (2) Polyacetal 0.062 --
-- -- 0.065 resin-copper alloy
TABLE-US-00002 TABLE 2 Example 6 7 8 9 10 (1) Base oil (mass %)
Lubricating oil A 42.50 89.50 44.25 87.00 43.00 Lubricating oil B
42.50 -- -- -- 21.50 Lubricating oil C -- -- 44.25 -- 21.50 (2)
Thickener (mass %) Thickener A 10.0 8.5 8.5 5.5 5.5 Thickener B --
-- -- 5.5 5.5 Thickener C -- -- -- -- -- Thickener D -- -- -- -- --
Thickener E -- -- -- -- -- (3) Added amount of 5.0 2.0 3.0 2.0 3.0
fatty acid and/or fatty acid metal salt (mass %) Fatty acid (molar
ratio) Caproic acid C6 -- -- -- -- -- Caprylic acid C8 -- -- 2 --
-- Lauric acid C12 -- -- -- -- -- Myristic acid C14 -- -- -- -- --
Palmitic acid C16 -- -- -- -- -- Behenic acid C22 -- -- -- -- --
Palmitoleic acid -- -- -- -- -- C16' Oleic acid C18' -- -- -- 1 --
Erucic acid C22' 2 -- -- -- 2 Linolic aid C18'' -- 1 -- -- -- Metal
(molar ratio) Magnesium -- -- -- -- -- Calcium 1 -- -- -- 1 Zinc --
-- -- -- -- Aluminium -- -- 1 -- -- Total (1) + (2) + (3) 100.0
100.0 100.0 100.0 100.0 Penetration 281 276 280 289 290 Dropping
point .degree. C. 178 178 178 210 207 Kinematic viscosity of 53.51
101.1 66.88 101.1 59.84 base oil (40.degree. C., mm.sup.2/sec)
Friction tests (friction coefficient) (1) Polyamide 0.067 0.060
0.068 0.064 0.067 resin-steel (2) Polyacetal -- 0.062 0.065 0.064
-- resin-copper alloy
TABLE-US-00003 TABLE 3 Example 11 12 13 (1) Base oil (mass %)
Lubricating oil A 86.00 -- 42.50 Lubricating oil B -- 42.50 42.50
Lubricating oil C -- 42.50 -- (2) Thickener (mass %) Thickener A
6.0 6.5 6.5 Thickener B -- -- -- Thickener C 6.0 -- -- Thickener D
-- 6.5 -- Thickener E -- -- 6.5 (3) Added amount of fatty acid 2.0
2.0 2.0 and/or fatty acid metal salt (mass %) Fatty acid (molar
ratio) Caproic acid C6 -- -- -- Caprylic acid C8 -- -- -- Lauric
acid C12 -- -- -- Myristic acid C14 -- -- -- Palmitic acid C16 --
-- -- Behenic acid C22 -- -- -- Palmitoleic acid C16' -- -- --
Oleic acid C18' 2 -- 2 Erucic acid C22' -- -- -- Linolic aid C18''
-- 2 -- Metal (molar ratio) Magnesium 1 -- -- Calcium -- -- -- Zinc
-- -- -- Aluminium -- 1 1 Total (1) + (2) + (3) 100.0 100.0 100.0
Penetration 267 276 269 Dropping point .degree. C. 204 203 188
Kinematic viscosity of base oil 101.1 38.66 53.51 (40.degree. C.,
mm.sup.2/sec) Friction tests (friction coefficient) (1) Polyamide
resin-steel 0.064 0.066 0.063 (2) Polyacetal resin-copper 0.066 --
0.064 alloy
TABLE-US-00004 TABLE 4 Comparative Example 1 2 3 4 5 6 (1) Base oil
(mass %) Lubricating 91.5 89.5 88.5 44.25 44.50 85.00 oil A
Lubricating -- -- -- 44.25 -- -- oil B Lubricating -- -- -- --
44.50 -- oil C (2) Thickener (mass %) Thickener A 8.5 8.5 8.5 8.5
5.5 6.0 Thickener B -- -- -- -- 5.5 -- Thickener C -- -- -- -- --
6.0 Thickener D -- -- -- -- -- -- (3) Added -- 2.0 3.0 3.0 -- 3.0
amount of fatty acid and/or fatty acid metal salt (mass %) Fatty
acid (molar ratio) Caproic acid -- 1 -- -- -- -- C6 Caprylic -- --
-- -- -- -- acid C8 Lauric acid -- -- -- -- -- -- C12 Myristic --
-- -- -- -- -- acid C14 Palmitic -- -- 2 -- -- -- acid C16 Behenic
acid -- -- -- 2 -- 1 C22 Palmitoleic -- -- -- -- -- -- acid C16'
Oleic acid -- -- -- -- -- -- C18' Erucic acid -- -- -- -- -- --
C22' Linolic acid -- -- -- -- -- -- C18'' Metal (molar ratio)
Magnesium -- -- -- -- -- -- Calcium -- -- -- -- -- -- Zinc -- -- --
-- -- -- Aluminium -- -- -- -- -- -- Total (1) + 100.0 100.0 100.0
100.0 100.0 100.0 (2) + (3) Penetration 273 275 281 278 265 267
Dropping 182 181 181 180 207 205 point .degree. C. Kinematic 101.1
101.1 101.1 53.51 66.8 101.1 viscosity of base oil (40.degree. C.,
mm.sup.2/sec) Friction tests (friction coefficient) (1) Polyamide
0.082 0.099 0.093 0.088 0.096 0.096 resin-steel (2) Polyacetal
0.101 -- 0.101 -- 0.099 -- resin-copper alloy
* * * * *