Note: Descriptions are shown in the official language in which they were submitted.
LUBRICATING GREASE COMPOSITION OF MIXED OILS, SOAP AND
RESIN
Technical Field
(0001) The present invention relates to a lubricating grease composition
for a
polyamide resin member to be supplied as a lubricant on the surface of at
least a
sliding portion of a polyamide resin member including the sliding portion
where,
for example, the other member comprising a resin member or a metal material
slides or which slides on the other member.
Background Art
(0002) Heretofore, greases have been used as lubricant compositions in
various industrial fields such as steels, automobiles, general machineries,
and
precision instruments. In recent years, polyamide resins have been commonly
used as the member for sliding portions, and the like, of automobile parts,
and
the like, for the purpose of improving heat resistance in light of being used
under
a high-temperature environment in addition to weight saving and cost saving.
[0003] The lubricating grease used at the sliding portion of the
polyamide
resin member is needed to have a property which does not cause the
deterioration (embrittlement) of the polyamide resin member in addition to
lubricity, low-temperature performance and heat resistance. However, when a
lithium soap grease or a urea grease commonly used is used as the lubricating
grease for a polyamide resin member, attacking properties against the
polyamide
resin member used under a high-temperature (e.g., 150 C) environment are
expressed and deteriorate the polyamide resin member, resulting in tending to
cause a problem of ruining the performance of machine parts made of the
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polyamide resin. Specifically, the lithium soap grease tends to be oxidized
and
deteriorate the polyamide resin member, and the urea grease itself has high
heat
resistance but when the resin is immersed under high-temperature environment
as described above, a part of the amine in urea is eliminated and the
eliminated
amine expresses attacking properties against the polyamide resin member,
resulting in tending to deteriorate the polyamide resin.
[0004] For example, Patent Literature 1 describes a lubricant composition,
for
the purpose of inhibiting the deterioration of the polyamide resin member
under
a high-temperature (140 C in Examples) environment, containing a synthetic
hydrocarbon oil, a urea-based thickener and zinc stearate and further at least
one
compound selected from the group consisting of trimellitic acid esters,
aromatic
sulfonamides, phthalic acid esters and hindered phenols.
[0005] However, as described above, the lubricant composition containing
the
urea-based thickener described in Patent Literature 1 expresses attacking
properties against the polyamide resin member under a high-temperature
environment and deteriorates the polyamide resin member, resulting in pose of
a problem of decreasing the performance of machine parts made of the
polyamide resin, particularly a breaking elongation.
Document List
Patent Literature
[0006]
Patent Literature 1: Japanese Patent Application Publication No. 2012-102191
Summary of Invention
Technical Problem
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[0007] Thus, it is an object of the present invention to provide a lubricating
grease
composition for a polyamide resin member capable of inhibiting the
deterioration of the polyamide resin member particularly under a high-
temperature use environment while having good low-temperature properties by
suitably adjusting a base oil and a thickener, thereby maintaining a breaking
elongation at a high level without substantially decreasing it.
Solution to Problem
[0008] For solving the above problems, the summary and construction of
the
present invention are as follows.
[0009] (1) A lubricating grease composition for a polyamide resin member
to
be supplied as a lubricant on a surface of at least a sliding portion of the
polyamide resin member including the sliding portion with an other member,
characterized in that the lubricating grease composition for a polyamide resin
member comprises a base oil which is a synthetic hydrocarbon oil, and a
thickener which is at least one metal complex soap selected from a barium
complex soap and a lithium complex soap, wherein a kinetic viscosity at 40 C
of
the base oil ranges from 30 to 200 mm2/s, and a drop point of the thickener is
270 C or more.
[0010] (2) The lubricating grease composition for a polyamide resin
member
according to the above (1), wherein the base oil is a single oil of a poly-a-
olefin
or a mixed oil of the poly-a-olefin and an ethylene-a-olefin copolymer.
[0011] (3) The lubricating grease composition for a polyamide resin
member
according to the above (1) or (2), wherein the other member is a metal member.
Effects of Invention
[0012] The present invention thus enables the provision of the
lubricating
grease composition for a polyamide resin member capable of inhibiting the
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deterioration of the polyamide resin member particularly under a high-
temperature use environment while having good low-temperature properties,
thereby maintaining a breaking elongation at a high level without
substantially
decreasing it by containing a base oil which is a synthetic hydrocarbon oil
and a
thickener which is at least one metal complex soap selected from a barium
complex soap and a lithium complex soap, wherein a kinetic viscosity at 40 C
of
the base oil ranges from 30 to 200 mm2/s and a drop point of the thickener is
270 C
or more.
Description of Embodiments
[0013] Next, embodiments of the present invention are described below.
[0014] The lubricating grease composition for a polyamide resin member
according to the present invention is to be supplied as a lubricant on the
surface
of at least a sliding portion of the polyamide resin member including the
sliding
portion with other member and has both good low-temperature properties and
outstanding mechanical properties (particularly a breaking elongation)
particularly under a high-temperature use environment
[0015] Examples of the other members include resin materials and metal
materials. The resin material may be resin materials having art identical
composition to or a different composition from the polyamide resin member.
Note that the lubricating grease composition of the present invention, when
the
other member is metal members, is preferable in term of rendering particularly
remarkable effects for the use as a lubricant on the surface of the polyamide
resin
member.
[0016] The "high-temperature (use) environment" herein refers to an
environment wherein an ambient temperature ranges from 130 to 150 C.
[0017] The lubricating grease composition of the present invention
contains a
base oil and a thickener.
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=
[0018] (Base oil) =
In the present invention, the base oil is a synthetic hydrocarbon oil, arid
the kinetic viscosity at 40 C of the base oil must range from 30 to 200 mm2/s.
This
is because when a kinetic viscosity at 40 C of the synthetic hydrocarbon oil
is
lower than 30 mrn2/s, the deterioration of the polyamide resin member
facilitates,
whereas when such a viscosity is higher than 200 mm2/s, a torque at a low
temperature (low-temperature torque) increases. Note that the base oil, when,
for example, an ester-based synthetic oil or an ether-based synthetic oil is
used
other than the synthetic hydrocarbon oil, may adversely affect the resin
members,
and it is thus preferable that the base oil be constituted only by the
synthetic
hydrocarbon oil. Examples of the synthetic hydrocarbon oil include poly-a-
olefins, ethylene-a-olefin copolymers and polybutene. Specific examples of the
particularly preferable base oil constituted by the synthetic hydrocarbon oil
include when the base oil is a single oil of a poly-a-olefin or when the base
oil is
a mixed oil of a poly-a-olefin and an ethylene-a-olefin copolymer.
[0019] In the present invention, the poly-a-olefin refers to a polymer
obtained
by homopolymerizing or copolymerizing monomers comprising one or two or
more of a-olefins having three or more carbon atoms.
[0020] The a-olefin herein is not particularly limited but examples thereof
include linear terminal olefins having preferably 3 to 30 carbon atoms, more
preferably 4 to 20 carbon atoms, further preferably 6 to 16 carbon atoms. More
specifically, propylene, 1-butene, 1-pentene, 1-hexene, and the like, are
included.
[00211 It is preferable that the poly-a-olefin have a mixing ratio ranging
from
67 to 91 mass% to the entire lubricating grease composition. Additionally,
when
the synthetic hydrocarbon oil is the mixed oil of the poly-a-olefin and an
ethylene-a-olefin copolymer, it is preferable that the poly-a-olefin have a
mixing
ratio ranging from 69 to 86 mass% to the entire lubricating grease
composition.
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[0022] Note that the degree of polymerization of poly-a-olefin is not
particularly limited and includes those usually termed the oligomers.
Additionally, one of the poly-a-olefins may be used singly or two or more
thereof
may be used in mixutre.
[0023] In the present invention, the ethylene-a-olefin copolymer refers to
a
copolymer comprising, as the constituent monomers, ethylene and one or two or
more of a-olefins having three or more carbon atoms.
[0024] The a-olefin in the ethylene-a-olefin copolymer herein is not
particularly limited but examples thereof include linear terminal olefins
having
preferably 3 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, further
preferably 6 to 16 carbon atoms. More specifically, propylene, 1-butene, 1-
pentene, 1-hexene, and the like, are included. Note that one of the poly-a-
olefins
may be used singly or two or more thereof may be used. Note that the ethylene-
.
a-olefin copolymer may have any of the structures of random copolymer,
alternating copolymer, periodic copolymer or block copolymer.
[0025] The number average molecular weight of the ethylene-a-olefin
copolymer ranges from 40,000 to 200,000, and the weight average molecular
weight of the ethylene-ix-olefin copolymer ranges from 40,000 to 200,000.
[0026] When the synthetic hydrocarbon oil is the mixed oil of the poly-a-
olefin and the ethylene-a-olefin copolymer, it is preferable that the ethylene-
a-
olefin copolymer have a mixing ratio ranging from 1.5 to 3.5 mass% to the
entire
lubricating grease composition. When a mixing ratio of the ethylene-a-olefin
copolymer is less than 1.5 mass%, the base oil viscosity may not be increased
to
a desirable numerical value within the suitable range, whereas such the
viscosity
is more than 3.5 mass%, the base oil viscosity may be much higher than the
suitable range.
[0027J (Thickener)
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In the lubricating grease composition of the present invention, the
thickener must be limited to at least one metal complex soap selected from a
lithium complex soap and a barium complex soap in light of being highly heat
resistant and not deteriorating the polyamide resin. Further, the drop point
of
the thickener must be limited to be 270 C or more in light of inhibiting the
deterioration of the polyamide resin member under a high-temperature
environment (during high-temperature endurance) of the lubricating grease
composition and maintaining a high breaking elongation to the polyamide resin
member. When a drop point of the thickener is less than 270 C, the lubricating
grease composition may attack and deteriorate the polyamide resin member
during high-temperature endurance.
[0028] The lithium complex soap herein refers to a soap obtained by
saponifying a plurality of carboxylic acids or esters with a lithium
hydroxide.
Additionally, the barium complex soap herein refers to a soap obtained by
saponifying a plurality of carboxylic acids or esters with a barium hydroxide.
[0029] Specific examples of the lithium complex soap or the barium
complex
soap include those obtained by reacting fatty acids such as stearic acid,
oleic acid,
palmitic acid, and/or hydroxy fatty acids having 12 to 24 carbon atoms
including
one or more hydroxyl groups in a molecule and at least one selected from the
group consisting of aromatic carboxylic acids, aliphatic dicarboxylic acids
having
2 to 20 carbon atoms (more preferably 4 to 12 carbon atoms) and carboxylic
acid
monoarnides with, for example, a lithium compound such as lithium hydroxide,
or a barium compound such as barium hydroxide.
[0030] The above hydroxy fatty acid having 12 to 24 carbon atoms is not
particularly limited and examples thereof include 12-hydroxystearic acid, 12-
hydroxylauric acid, 16-hydroxypalmitic acid, with 12-hydroxystearic acid being
particularly preferable among these,
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[0031] Examples of the
aromatic carboxylic acid include benzoic acids,
phthalic acids, isophthalic acids, terephthalic acids, trimellitic acids,
pyromellitic
acids, salicylic acids, p-hydroxybenzoic acids, and the like.
[0032] Further, the above
aliphatic dicarboxylic acid having 2 to 20 carbon
atoms is not particularly limited and examples thereof include oxalic acids,
malonic acids, succinic acids, methylsuccinic acids, glutaric acids, adipic
acids,
pimelic acids, suberic acids, azelaic acids, sebacic acids,
nonamethylenedicarboxylic adds, decamethylenedicarboxylic acids,
undecanedicarboxylic acids, dodecanedicarboxylic acids, tridecanedicarboxylic
acids, tetradecanedicarboxylic acids, pentadecanedicarboxylic acids,
hexadecanedicarboxylic acids, hep tadecaned icarboxylic
acids,
octadecanedicarboxylic acids, and the like, with adipic acids, pimelic acids,
suberic acids, azelaic acids, sebacic acids, nonamethylenedicarboxylic acids,
decarnethylenedicarboxylic acids,
undecanedicarboxylic acids,
dodecanedicarboxylic acids, tridecanedi carboxylic acids,
tetradecanedicarboxylic adds,
pentadecanedicarboxylic acids,
hexadecanedicarboxyli c acids,
heptadecanedicarboxylic acids,
octadecanedicarboxylic acids, and the like, being preferably used. Of these,
azelaic acids and sebacic acids are preferable.
[0033] Further, examples
of the carboxylic acid monoarnide include those in
which one of the carboxyl groups of the above dicarboxylic acid is amidated.
Preferable examples include those in which one of the carboxyl groups of
azelaic
acid or sebacic acid is amidated.
[0034] Examples of the
amine to be amidated include aliphatic primary
amines such as butylamine, amylamine, hexylamirte, heptylamine, octylamine,
nonylamine, decylamine, laurylamine, myristyl amine, palmityl amine, stearyl
amine, and behenyl amine, aliphatic secondary amines such as dipropylamine,
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diisopropylamine, dibutylamine, diamylamine, dilaurylamine, monomethyl
laurylamine, distearylamine, monomethyl stearylamine, dimyristylarnine, and
dipalmitylamine, aliphatic unsaturated amines such as allylamine,
diallylarnine,
oleylamine, and dioleyIarnine, alicyclic amines such as cydopropylarnine,
cyclobutylamine, cyclopentylamine, and cyclohexylamine, aromatic amines such
as aniline, methylaniline, ethylaniline, benzylamine, dibenzylarnine,
diphenylamine, and a-naphthylamine, with hexylamine, heptylamine,
octylamine, nonylamine, decylamine, laurylamine, myristyl amine, palmityl
amine, stearylamine, behenyl amine, dibutylamine, diamylamine, monomethyl
laurylamine, monomethyl stearylamine, oleylamine, and the like, being
preferably used,
[0035] When the lithium complex soap or the barium complex soap is mixed,
carboxylic acids and/or esters thereof and the above metal hydroxide may be
fed
to the base oil and saponified in the base oil to be mixed.
[0036] When the lithium complex soap or the barium complex soap is
prepared by carrying out the saponification reaction in the base oil, it is
preferable
to use the combination of stearic acid and/or 12-hydroxystearic acid as the
carboxylic acid and azelaic acid or sebacic acid and the like.
[0037] Note that when the saponification reaction is carried out in the
base oil,
a plurality of carboxylic acids and/or esters thereof and acid amide may be
saponified simultaneously or may be saponified sequentially.
[00381 When the thickener is the lithium complex soap, the mixing ratio to
the
entire lubricating grease composition is preferably 8 to 18 mass%. When a
mixing
amount is less than 8 mass%, the degree of oil separation may increase likely
decreasing the storage stability of the lubricating grease composition,
whereas
when such an amount is higher than 18 mass%, the low-temperature torque at a
low temperature may increase.
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[0039] When the thickener is the barium complex soap, the mixing
ratio to the
entire lubricating grease composition is preferably 27 to 33 mass%. When a
mixing amount is less than 27 mass%, the degree of oil separation may increase
likely decreasing the storage stability of the lubricating ,grease
composition,
whereas when such an amount is higher than 33 mass%, the low-temperature
torque at a low temperature may decrease.
[0040] (Others)
To the grease composition, other additives such as an antioxidant, a
rust preventive, an extreme pressure agent, an oily agent, and a viscosity
index
improver, which have been added to the greases can be added as necessary in a
= range within which the effects of the present invention are not affected.
[0041] Examples of the antioxidant include phenol-based antioxidants
such
as 2,6-ditertiary butyl-4-methylphenol and 4,4'-methylenebis(2,6-ditertiary
butylphenol), amine-based antioxidants such as alkyl diphenylamine,
= triphenylamine, phenyl-a-naphthylamine, phenothiazine, alkylated phenyl-a-
naphthylarnine, and alkylated phenythiazine. Additionally, phosphorus-based
antioxidants and sulfur-based antioxidants are also used.
[0042] Examples of the rust preventive include Ca salts or Na salts
of aromatic
sulfonic acids or saturated aliphatic dicarboxylic acids, fatty acids, fatty
acid
amines, alkylsulforlic acid metal salts, alkylsulfonic acid amine salts,
oxidized
paraffins, polyoxyalkyl ethers, and the like.
[0043] Examples of the extreme pressure agent include phosphorus-
based
compounds such as phosphate esters, phosphite esters, and phosphate ester
amines, sulfur-based compounds such as sulfides, and disulfides, sulfur-based
compound metal salts such as dialkyldithiophosphoric acid metal salts
(excluding zinc salts) and dialkyldithiocarbamic acid metal salts, chlorine-
based
compounds such as chlorinated paraffins and chlorinated diphenyls, and
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organometallic compounds such as molybdenum dialkyldithiocarbamates
(MoDTP), and the like.
[0044] Examples of the oily agent include fatty acids or esters thereof,
higher
alcohols, polyhydric alcohols or esters thereof, aliphatic esters, aliphatic
amines,
aliphatic monoglycerides, montan waxes, amide-based waxes, and the like.
100451 Examples of the viscosity index improver include polymethacrylates,
ethylene-propylene copolymers, polyisobutylenes, polyalkylstyrenes, styrene-
isoprene hydrogenated copolymers, and the like.
100461 The composition is prepared by a method wherein each of the above
components are added in a predetermined amount and thoroughly kneaded
using a triple roll or a high-pressure homogenizer.
Example
[0047] Hereinafter, the present invention is described in further detail in
reference with Examples but not limited to these Examples,
[0048] (Examples 1 to 7 and Comparative Examples 1 to 6)
(1) Preparation method of lubricating grease compositions
= The preparation method of lubricating grease compositions was
carried out by the following method.
(1-1) Case in which the lithium complex soap (Li-Comp) was used as
the thickener
First, the base oil and 12-hydroxystearic acid (thickener component)
and lithium hydroxide (thickener component) were mixed in predetermined
amounts in a mixing and stirring tank and stirred with heating at about 80 to
130 C to carry out the saponification reaction. Further, azelaic acid
(thickener
component) was mixed in a predetermined amount and stirred with heating at
about 80 to 200 C, to which lithium hydroxide (thickener component) was
further
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added to carry out the saponification reaction, followed by cooling to produce
a
gelatinous substance. Each of the additives was added to the produced
gelatinous substance, stirred and subsequently passed through a roll mill or a
high-pressure homogenizer to prepare lubricating grease compositions
containing each of the components shown below in the mixing amounts (mass%)
shown in Table 1 and Table 2. The saponification reaction was carried out for
1
hour or more for the lubricating grease composition with which thickener A was
mixed and less than 30 minutes. for the lubricating grease composition with
which thickener E was mixed. Note that the amount of each component
constituting the thickeners A, E mixed was, in both thickeners, 63.5 mass% of
12-
hydroxystearic acid, 19 mass% of azelaic acid and 17.5 mass% of lithium
hydroxide, to the total amount of the thickener.
[0049] (1-2) Case in
which the barium complex soap (13a-Comp) was used as
the thickener
First, the base oil and sebacic acid (thickener component) and
carboxylic acid monostearyl amide (thickener component) were mixed in
predetermined amounts in a mixing and stirring tank and stirred with heating
at
about 80 to 200 C, to which barium hydroxide (thickener component) was added
to carry out the saponification reaction, followed by cooling to produce a
gelatinous substance. Each of the additives was added to the produced
gelatinous substance, stirred and subsequently passed through a roll mill or a
high-pressure homogenizer to prepare lubricating grease compositions
containing each of the components shown below in the mixing amounts (mass%)
shown in Table 1 and Table 2. The saponification reaction was carried out for
30
minutes or more for the lubricating grease composition with which thickener B
was mixed and less than 15 minutes for the lubricating grease composition with
which thickener F was mixed. Note that the amount of each component
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constituting the thickeners B, F mixed was, in both thickeners, 27.5 mass% of
sebacic acid, 41.5 mass% of carboxylic acid monostearyl amide and 31 mass% of
barium hydroxide, to the total amount of the thickener.
[0050] (1-3) Case in which the lithium soap (Li-OHST) was used as the
thickener
First, the base oil and 12-hydroxystearic acid (thickener component)
and lithium hydroxide (thickener component) were mixed in predetermined
amounts in a mixing and stirring tank and stirred with heating at about 80 to
130 C to carry out the saponification reaction. The mixture was further
stirred
with heating to a melting temperature and subsequently cooled to produce a
gelatinous substance. Each of the additives was added to the produced
gelatinous substance, stirred and subsequently passed through a roll mill or a
high-pressure homogenizer to prepare lubricating grease compositions
containing each of the components shown below in the mixing amounts (mass%)
shown in Table 2. Note that the amount of each component constituting the
thickener C mixed was 88 mass% of 12-hydroxystearic acid and 12 mass% of
lithium hydroxide, to the total amount of the thickener.
[0051] (1-4) Case in which Urea was used as the thickener
First, the base oil and diphenylmethane diisotyanate (thickener
component) and octylamine (thickener component) were stirred with heating at
70 to 180 C to carry out the reaction, and the temperature was elevated and
cooled to produce a gelatinous substance. Each of the additives was added to
the
produced gelatinous substance, stirred and subsequently passed through a roll
mill or a high-pressure homogenizer to prepare lubricating grease compositions
containing each of the components shown below in the mixing amounts (mass%)
shown in Table 2. Note that the amount of each component constituting the
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thickeners D mixed was 50 mass% of diphenylmethane diisocyanate and 50
mass% of octylarnine, to the total amount of the thickener.
[00521 Poly-cc-olefin
A: 40 C kinetic viscosity 30 mm2/s (a product of INEOS
Oligomers Japan DURASYNTm 166)
Poly-a-olefin13; 40 C kinetic viscosity 46 mrrizis (a product of INEOS
Oligomers Japan DURASYNThl 168)
Poly-a-olefin C: 40 C kinetic viscosity 5 mm2/s (a product of INEOS
Oligomers Japan DURASYNTM 162)
Poly-a-olefin D: 40 C kinetic viscosity 400 mm2/s (a product of INEOS
Oligomers Japan DURASYNTm 174)
Ethylene-a-olefin copolymer: number average molecular weight 68000,
weight average molecular weight 147000 (a product of SHOWA VARNISH CO.,
LTD. L6Z-25)
Thickener A: Li-Comp having a drop point at 280 C (lithium complex
soap)
Thickener B: Ba-Comp having a drop point at 270 C (barium complex
soap)
Thickener C: Li-OHST having a drop point at 200 C (lithium soap)
Thickener D: Urea having a drop point at 270 C (urea)
Thickener E: Li-Comp having a drop point at 255 C (lithium complex
soap)
Thickener F: Ba-Comp having a drop point at 230 C (barium complex
soap)
Antioxidant: Phenylnaphthylamine (a product of SANYO CHEMICAL
INDUSVRIES, Ltd. VANLUBETm 81)
Rust preventive: neutral calcium sulfonate (a product of KING
Industries, Inc., NA SULTM CA 1089)
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[0053] (2) Evaluation method
(2-1) Base oil viscosity
The base oil viscosity was measured in accordance with JIS 1(2283: 2000.
[0054] (2-2) Worked penetration
The worked penetration was measured in accordance with JIS K2220.
7: 2013.
[0055] (2-3) Drop point
The drop point was measured in accordance with JIS 1<2220. 8: 2013.
[0056] (2-4) Low-temperature property (low-temperature torque)
In accordance with JIS 1(2220. 18: 2013, the maximum torque (starting
torque) at -40 C obtained at the run-up time was measured. In the present
invention, a numerical value (index) of the starting torque of 27 or less was
defined as the passing level, whereas such a value of more than 27 was defined
as failure.
[0057] (2-5) Compatibility of the resin with the grease composition under a
high temperature use environment (breaking elongation)
The grease was applied in a thickness of about 1 mm to the surface of
Nylon 66 (registered trademark) as a test specimen prescribed in )IS K7162:
1994,
the test specimen was allowed to stand in a thermostat at 150 C for 500 hours,
subsequently the lubricant was wiped off, and the tensile test prescribed in
JIS
K7162 (Plastics - Determination of Tensile Properties - Part 1: General
principles)
was carried out to measure a breaking elongation. In the present invention, a
breaking elongation of 30% or more was defined as the passing level, whereas
such an elongation of less than 30% was defined as failure.
[0058] (3) Evaluation results
The evaluation results on the low-temperature properties (low-
temperature torque) and the high-temperature properties (breaking elongation)
=
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when each of the lubricating grease compositions was applied to the polyamide
resin member are shown in Table 1 and Table 2.
[0059] [Table 11
Example No. 1 , 2 3 4 .5 6 7
Poly-cu-olefin A 84.4 ¨ 84,9 ¨ 67.4 69.4
90,4
Base oil Poly-a-olefin B ¨ 82.4 ¨ 85.6 ¨ ¨
Ethylene-a-olefin copolymer ¨ ¨ 1.5 2.8 ¨ 2
Thickener A. . 15 17 13 11 ¨ ¨ 9
=
Thickener
Thickener B ¨ ¨ ¨ ¨ 32 28 ¨
Antioxidant 0.5 0,5 0.5 0.5 0.5 0.5 0.5
Other
additives
Rust preventive 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Total (mass%) 100 100 100 100 100 100 100
Base oil 40 C kinetic viscosity (rnm2is) 30 46 100 200 30 46
30
Worked penetration of lubricating grease 265 255 275 290 275
295 310
Drop point of thickener ( C) 280 280 275 280 270 270 280
Low-temperature property: -40 C
16 21 16 19 25 27 13
starting torque
Performance
Resin compatibility: breaking
32 30 33 32 40 43 31
elongation (%)
[0060] [Table 2]
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Comparative Example No. 1 2 3 4 5 6 =
Poly-a-olefin A 84.4 69.4 88.4 86.4 ¨
Base oil Poly-a-olefin C ¨ ¨ 84.4 ¨
Poly-a-olefin D ¨ 84.4
Thickener A 15 15
Thickener B ¨ ¨
Thickener C
Thickener
Thickener D
Thickener E 15
Thickener F 30 ¨
Antioxidant 0.5 0.5 0.5 0.5 0.5 0.5
Other
additives
Rust preventive 0.1 0.1 0.1 0.1 0.1 0.1
Total (mass%) 100 100 100 100 100 100
Base oil 40 C kinetic viscosity (mm2/s) 30 30 30 30 5 4.01
Worked penetration of lubricating grease 280 260 270 285 275
265
Drop point of thickener ( C) DI 230 2.124 270 280 280
Low-temperature property: -40 C
15 24 14 16 12 4.
starting torque
Performance
Resin compatibility: breaking
21 22 10 22 24 30
elongation (%)
(Note) The underlines at the numerical values in Table 2 indicate that the
values
are outside the suitable range of the present invention and the performance
failed
to achieve the passing level.
[0061] From the evaluation results shown in Table 1, all of Examples 1 to 7
maintained the starting torques at -40 C as low as 13 to 27 and the breaking
elongations as high as 30 to 43%, thereby revealing good compatibility of the
polyamide resin member with the grease compositions.
[00621 In contrast, from the evaluation results shown in Table 2, all of
Comparative Examples 1 to 6 failed to achieve the passing levels of numerical
values in either of the starting torque at -40 C or the breaking elongation.
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CA 02980989 2017-09-26
Industrial Applicability
[0063] The present
invention thus enables the provision of the lubricating
grease composition for a polyamide resin member capable of inhibiting the
deterioration of the polyamide resin member particularly under a high-
temperature use environment while having good low-temperature properties,
thereby maintaining a breaking elongation at a high level without
substantially
decreasing it. The lubricating grease composition of the present invention is
suitable to be used at a sliding portion of various machine parts constituting
automobile, machine, electrical and electric equipment, and the like, that use
resin materials such as polyamide resins, Specifically, in an automobile,
examples include rolling bearings, sliding bearings and gear parts and cam
parts
of automobile accessories such as electric radiator fan motors, fan couplings,
electronically controlled EGR, electronically controlled throttle valves,
alternators, and electric power steerings, to which the lubricity is demanded.
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