Note: Descriptions are shown in the official language in which they were submitted.
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SURFACE COATING MEMBER
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention concerns a surface coating
member and, more in particular, it relates to a surface
coating members prepared by applying a lubricating coating
to the surface of a rubber or plastic member such as wiper
blade, seal packing, O-ring, weather strip, glass run,
timing belt, rubber bellows, gear and door catcher. More
in particular, the present invention relates to a surface
coating member suitable as a surface-coated sliding member
such as a wiper blade, glass run, weather strip and O-ring
whose surface is in sliding contact with other members.
Description of the Prior Art
For a wiper blade rubber, a molding product of natural
rubber or synthetic rubber has been employed so -far.
However, the wiper rubber of this kind has the following
drawbacks and hence is not always satis-factory.
That is, since an adhering phenomenon occurs between
the wiper blade rubber and a glass surface in the damp-
drying state or under cold climate condition, to bring
about a so-called "locking phenomenon" in which the wiper
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operation is blocked, or a so-called "trembling phenomenon",
that is, self-e~citing vibration due to the negative cha-
racteristics of the velocity dependency of the frictional
coefficient. This leads to problems such as (1) unsatis-
factory wiping, (2) abnormal abrasion at the surface of
the blade rubber, (3) shortening for the life in each of
the connection portions of the wiper system,(4) increase
in the consumption power for the operation motor and (5)
eyesore and grating due to the trembling phenomenon.
For overcoming such problems, Japanese Patent Laid-
Open Sho 55-15873 proposes to coat the rubber surface
of a wiper blade with a silicone composition containing
molybdenum disulfide.
However, in the wiper blade rubber having such a
coating as described in the above-mentioned patent publi-
cation, it has been found that the durability of the coating
layer becomes poor. The problem also occurs in the weather
strip or the glass run.
Further, the following drawbacks are also caused
between the metal surface and the rubber material and the
coating material not always has a satisfactory property.
That is, in an oil seal or gasoline cap seal, sticking
occurs between the rubber and the metal surface to increase
torque upon opening and closure. In an O-ring, packing or
timing belt, there happens abnormal abrasion, stick slip
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or generation of ringing OWiIlg to high sliding resistance
between the rubber and the metal surface. Also in rubber
bellows, puncture occurs due to the abnormal abrasion.
Further, in a gear or door catcher made of polyacetal,
nylon resin, etc. abnormal abrasion, ringing or creaking
occurs.
For overcoming the foregoing problems, although a
countermeasure such as coating of grease has been applied,
this lacks in durability.
OBJECT AND SUMMARY OF THE INVENTION
The ob~ect of the present invention is to overcome
the foregoing problems and provide a surface coating member
having excellent sliding property and also high durability
of the coating layer.
The sur-face coating member according to the present
invention comprises a surface coating member in which a
coating layer containing a solid lubricant and a resin
matrix is formed at the surface, in which the resin matrix
comprises a fluoro-olefin vinyl ether polymer resin and/or
a fluoro-olefin vinyl ether vinyl ester copolYmer resin.
There is no particular restriction to rubber or plastic
constituting the main body portion of the coating member
according to the present invention but various kinds of
rubber and plastic can be employed. The rubber may be
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either of natural or synthetic rubber. As an example o-f
the synthetic rubber, there can be mentioned, for instance,
styrene butadiene rubber, butadiene rubber, isoprene rubber,
ethylene propYlene rubber (EPM, EPDM), acrylonitrile buta-
diene rubber, chloroprene rubber, isobutylene isoprene
rubber, al*in rubber, polyether rubber, polysulfide rubber,
silicone rubber, acrylic rubber, fluoro rubber, halogenated
polyethylene rubber, urethane rubber, ethylene vin~l
acetate rubber, high styrene rubber and acrylonitrile
isoprene rubber. Among themj EPDM is particularly,
preferred.
As the plastic material, either of a thermosetting
resin or a thermoplastic resin may be used.
As an example of the plastic, there can be mentioned,
for instance, ABS resin, ABS blend, acetal resin (homo-
polymer), acryl resin, ACS resin, alkyd resin, amino resin,
ASA resin, cellulose type resin, chlorinated polyether,
diallyl phthalate resin, epoxy resin, ethylene - vinyl
acetate copolymer, fluoro resin, ionomer, methyl pentene
polymer, phenol resin, polyamide (nylon), polyallyl ether,
polyallyl sulfone, polybutene-1, polycarbonate, unsaturated
polyester resin, polyethylene, polyethylene terephthalate
(tetron), polyimide, polyamideimide, polyphenYlene oxide,
polyphenylene sulfide, polypropylene, polystyrene, poly-
sulfone, polyether sulfone, polyurethane, vinyl chloride
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resin and polyallylate.
The coating layer coating the rubber or plastic
comprises a solid lubricant and a resin matrix.
As the resin matrix, a fluoro-ole-fin vinyl ether
polymer resin and/or a fluoro-olefin vinyl e-ther vinyl
ester copolymer resin may be used.
~ s the solid lubricant, there can be used, for example,
sulfide such as molybdenum disulfide and tungsten disulfide,
fluoride such as polytetrafluoro ethylene and fluorinated
graphite, graphite and silicone powder. The solid lubricant
described above may be used alone or as a combination of two
or more of them. In the present invention, combined use of
the sulfide, fluoro compound and graphite is preferred in
view of the excellent lubrication resistance, fitness and
feeling. In this case, the blending ratio for the sulfide,
fluoro compound and graphite is preferably ~rom 10 to 1500
parts by weight of the sulfide and 100 to 3000 parts by
weight of the fluoro compound based on 100 parts by weight
of the graphite.
It is desirable that the solid lubricant has an average
grain size of less than 10/um, preferably, less than 5 ~m,
particularly, preferably, less than 3/um. The blending
ratio o-f the solid lubricant and resin matrix is preferably
from 50 to 95 parts by weight of the solid lubricant and
50 to 5 parts by weight of the resin matrix and, more
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preferably, from 70 to 90 parts by weight of the solid
lubricant and 30 to 10 parts by weight of the resin
matrix.
For forming the coating on the surface of the rubber
or the plastic in the present invention, the solid lubri-
cant, the resin matrix and a curing agent may be coated
being dispersed or dissolved in an organic solvent.
As the curing agent, there can be used, for
example, polyisocyanate and melamine resin.
As the organic solvent, methyl ethyl ketone, toluene,
xylene, isopropyl alcohol, isobutanol, n-butanol, butyl
acetate, MIBK and cellosolve acetate are preferred, for
example.
As the coating method, various method such as brushing,
spraying or dipping maY be employed. Prior to the coatin~,
the sur~ace of the rubber or plastic may be cleaned or a
surface treatment may be applied for improving the fitness
with the resin matrix. For the surface treatment, a primer
treatment can be mentioned.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 is a schematic side elevational view for
illustrating the method of experiment.
g
DESCRIPTION OF PREFERRED EM~ODIMENTS
The present will now be explained with reference to
examples and comparative examples.
Compositions shown in the following (Comparative
Example 1) - (Comparative Example 4), as well as (Example
1) - (Example 9) were sprayed on the surface of rubber
pieces, and the compositions were cured under the curing
conditions (heating conditions) shown for each of them,
to form a coating layer at a thickness of 10 ~m to the
surface of each of the rubber pieces. Each rubber piece
was cut into a size o-f 10 mm x 6 mm x 2 mm to prepare a
test piece. The coating surface was formed on the 10 mm x
6 mm surface of the test piece.
The test piece was mounted to FALEX No. 1 Tester
(Faville-Levally Corporation) and the durability of the
coating layer was examined.
Fig. 1 is a schematic side elevational view illustra-
ting the state of the test, in which a test piece was held
to a test piece holder 2 and urged to the outer circumfe-
rential surface of a ring 3 of 35 mm diameter under a load
of 9.06 kg (20 LBS). The outer circumferential surface of
the ring 3 was made of SAE 4620 steel and the surface
roughness was 6 - 12 rms. The ring 3 was reciprocally
rotated around the axial center as shown by arrows within
a rotational range of 90 at a rate of 100 cycle/min.
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The number of cycles at which the frictional coeffi-
cien~ reached 0.2 was measured as a life cycle. In a case
where the coating layer was abraded to expose the rubber
layer before the frictional coefficient reached 0.2, the
number of cycles up to that time was defined as the life
cycle.
The life cycle for each of the comparative examples
and the examples is as shown in Table-l. The static
-frictional coefficient and the dynamic frictional coef-
ficient at the surface of the coating layer for each of
the test pieces before the sliding movement with the ring
3 were measured and the results are also shown together in
Table-l.
From Table-l, it can be seen that the test pieces of
Examples 1 - 9 according to the present invention have low
friction coefficient and the durability of -the coating
layer was remarkably high.
The average grain size of the solid lubricant used
hereinafter is less than 5Jum in each of the cases.
In the following descriptions, "parts" means "parts
by weight".
(Comparative Example 1)
(Polyurethane resin) Nipporan 5185 100 parts
(manufactured by Nippon Polyurethane Industry co.)
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(Isocyanate curing agent) Coronate HL10.0 parts
Curing conditions: 80C - 30 min.
(Comparative Example 2)
(Polyurethane resin) Nipporan 518526.0 parts
(manufactured by Nippon Polyurethane Industry co.)
(Molybdenum disulfide) Technical grade30.0 parts
(manufactured by Climax Molybdenum Co.)
(Polytetrafluoroethylene) Lubron L-542.0 parts
(manufactured by Daikin Industry Co.)
(Graphite) ACP 1000 2.0 parts
(manufactured by Nippon Graphite Industry Co.)
(Isocyanate curi~g agent) Coronate HL2.6 parts
Curing conditions: 80C - 30 min.
Comparative Example 3) (corresponding to Example 3 in
Japanese Patent Laid-Open Sho
55-15~73)
KM-765 (Emulsion with 20% silicone content) 45 parts
(manu~actured by Juetsu Chemical Co.)
C-PM-4F (catalyst, manufactured by Juetsu
Chemical Co.) 4.5 parts
Molybdenum disulfide (4.5 / m average grain size) 4.0 parts
Water 52.0 parts
Curing condition: After leaving at a room temperature for
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10 min, a cured laYer was obtained at 150C - 10 min
(Comparative Example 4)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 100 parts
(manufactured by Dainippon Ink Chemical Industry Co.)
(Isocyanate curing agent) Barnock DN980 24 parts
(manufactured by Dainippon Ink Chemical Industry Co.)
Curing condition: 80C - 10 min.
(Example 1)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 26 parts
(manufactured by Dainippon Ink Chemical Industry Co.)
(Molybdenum disulfide) Technical grade 30 parts
(manufactured by Climax Molybdenum Co.)
(Polytetrafluoro ethylene) Lubron L-5 42 parts
(manufactured by Daikin Industry Co.~
(Graphite) ACP 1000 2 parts
(manufactured by Nippon Graphite Industry Co.)
(Isocyanate curing agent) Barnock DN980 6.2 parts
(Dainippon Ink Chemical Industry Co.)
Curing condition: 80C - 10 min.
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(Example 2)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 28 parts
(manu-factured by Dainippon Ink Chemical Industry Co.)
(Molybdenum disulfide) Technical grade10 parts
(manufactured by Climax Molybdenum Co.)
(Polytetrafluoro ethylene) Lubron L-560 parts
(manufactured by Daikin Industry Co.)
(Graphite) ACP 1000 2 parts
(manufactured by Nippon Graphite Industry Co.)
(Isocyanate curing agent) Barnock DN9806.7 parts
(Dainippon Ink Chemical Industry Co.)
Curing condition: 80C - 10 min.
(Example 3)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 28 parts
(manufactured by Dainippon Ink Chemical Industry Co.)
(Molybdenum disulfide) Technical grade47 parts
(manufactured by Climax Molybdenum Co.)
(Polytetrafluoro ethylene) Lubron L-523 parts
(manufactured by Daikin Industry Co.)
(Graphite) ACP 1000 2 parts
(manufactured by Nippon Graphite Industry Co.)
-- 11 -
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(Isocyanate curing agent) Barnock DN9806.7 parts
(Dainippon Ink Chemical Industry Co.)
Curing condition: 80C - 10 min.
(Example 4)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 49 parts
(manufactured by Dainippon Ink Chemical Industry Co.)
(Molybdenum disulfide) Technical grade 39 parts
(Polytetrafluoro ethylene) Lubron L-5 10 parts
(Graphite) ACP 1000 2 parts
(Isocyanate curing agent) Barnock DN9806.7 parts
Curing condition: 80C - 10 min.
(Example 5)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 49 parts
(Molybdenum disulfide) Technical grade 47 parts
(Polytetrafluoro ethylene) Lubron L-5 2.5 parts
(Graphite) ACP 1000 1.5 parts
(Isocyanate curing agent) Barnock DN98012.0 parts
Curing condition: 80C - 10 min.
(Example 6)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
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v
Fluonate K702 49 parts
~Molybdenum disulfide) Technical grade49 parts
(Graphite) ACP 1000 2 parts
(Isocyanate curing agent) Barnock DN98012 parts
Curing condition: 80C - 10 min.
(Example 7)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate ~702 39 parts
(Molybdenum disulfide) Technical grade59 parts
~Graphite) ACP 1000 2 parts
(Isocyanate curing agent) Barnock DN9809.4 parts
Curing condition: 80C - 10 min.
(Example 8)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 28 par~s
(Molybdenum disulfide) Technical grade70 parts
(Graphite) ACP 1000 2 parts
~Isocyanate curin~ agent) Barnock DN980 6.7 parts
Curing condition: 80C - 10 min.
(Example 9)
(Fluoro-olefin vinyl ether vinyl ester copolymer)
Fluonate K702 20 parts
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(Mol~bdenum disulfide) Technical grade 78 parts
(Graphite) ACP 1000 2 parts
(Isocyanate curing agent) Barnock DN980 4.8 parts
Curing condition: 80C - 10 min.
.
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As has been described above, the surface coating
member according to the present invention has an
extremely low friction coefficient for the coating
surfaee and the durability of the eoating layer is
remarkably high.
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