Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to a compound which contains a
fluorocarbonpolymer and possesses rubber~like elasticity.
Additionally, the invention is concerned with a coating compound
as described below and the method of manufacture of such a
compound for coating the surface of any object to form a coating
film thereon having the property of self-lubrication which is
peculiar to fluorocarbonpolymer and having the characteristics of
free deformation in elongation, bending and contraction by the
effect of external force but which can be restored to its original
state after the relief of such external force.
All of the fluorocarbonpolymers such as polytetrafluoroethylene
(abbreviated to PTFE hereunder), tetrafluoroethylenehexafluororo,pylene
copolymer (abbreviated to FEP hereunder) have self-lubrication
and non-adhesive characteristics so that they are widely utilized
for industrial and household uses as the fine powder of such
polymers when applied on the surface of an object can be melted to
produce a very slippery or non-adhesive film. However, the process
of heating and melting such fluorocarbonpolymers after they are
coated on the surface of the object is complicated and it is im-
possible to apply heat on any object which may be deteriorated by
the heating as the melting point of such polymers coated on the
surface of objects are too high.
Therefore, there is also used a method of coating a compound
consisting of a fine powder of fluorocarbonpolymer or a liquid
dispersion of it combined with thermoplastic or a thermosetting
resin on the surface of an object to constitute a slippery or non-
adhesive film thereon by letting the film dry in air or at a temper-
ature less than the melting point of the f:Luorocarbon~olymer to
avoid deterioration of the object. For instance, U.K. Patent No.
1,018,269 dated January 26, 1966 entitled, Improvements in or
Relating to Resin Compositions, specifies that a compound consisting
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a low molecular weight PTFE and a thermoplastic ~r thermosetting
resin can form a hard film under normal temperature and it is
possible to obtain a fluorocarbon coating film with this compound
not only on the surface of a metallic object but even on the
surface of wood or paper which is quite liable to deteriorate from
heat. It is also specified in the U.K. Patent No. 1,06~,840 dated
April 12, 1967 entitled Tetrafluoroethylene/herafluoropropylene
Copolymer Dispersions, that a compound consisting of FEP organosol
and a thermoplastic or thermosetting resin can produce a coating
film of fluorocarbonpolymer on the surface of an object by heating
the coated film at a temperature lower than the melting point of
the fluorocarbonpolymer.
However, it is obvious through the reports of practical
tests included in the specifications of the above patent that every
thermoplastic or thermosetting resin employed as the film forming
material combined with fluorocarbonpolymer can adhere firmly to a
hard object such as a metallic material but its film is very hard and
lacks the properties of elongation and flexibility. Therefore, when
the compounds as mentioned above are applied on the surface of rubber
or rubber-like elastic objects and dried by normal temperature for
thermoplastic resin or heat-treated by predetermined temperatures
to form the surface coating film, the film will easily be cracked
by bending or compressing owing to the hard film created by the
film forming material and also due to the characteristics of
of rubber or rubber-like elastic objects which may have been
deteriorated by the heat treating of the thermosetting resin
where it was used in lieu of thermoplastic resin. Rubber or
rubber-like elastic material is high in friction strength so that
minimizing the friction strength on the surface of rubber or rubber-
like materials permits full use of its elastlcity and flexibility,The field of application of it is much extended. In order to give
the self-lubrication and non-adhesi~e characteristics of fluoro-
carbonpolymer to the surface of rubber or rubber-like elastic
material, it has been tried for instance, to fill it with a fine
powder of PTFE or FEP. It was found very difficult, however
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~ ~ ;float the fine powder of PTFE or FEP to the surface o~ the rubber
; or rubber-like material due to its high in viscosit~, I-t required
a mix and blend of at least 50% by weight oE fine powder o~ PTFE ~r
FEP based on the total weight of the composition containing the rubber
or rubber-like material in order to achieve a suitable slippery
surface on it. ~he above method is not practically useful as
it has a high cost of product from the use of large amounts of
fluorocarbonpolymer and also will cause considerable deterioration
of the original characteristics of the rubber or rubber-like
material.
For the reasons mentioned above, it is impossible to make a
coating film having the characteristics of slipping and flexibility
of deformation on the surface of the rubber or rubber-like material
without deteriorating the original nature of the base object.
The inventor of the invention has prepared several compounds
consisting of a wax-like low molecular weight PTFE as being used
by the said U.K. Patent No. 1,018,269 or FEP organosol as specified
in the said U.K. Patent N0. 1.064,840 and soft type rubber-like
elastic material polyurethane rubber or polychloroprene insolution
as film forming material in lieu of thermoplastic or thermosetting
`~ hard type film forming material as also being used by the above
patents, Each of the compounds produced as above were coated on the
surface of a rubber or rubber-like object and dried to form a film
and then the characteristic of each film was investigated, The
result of the investigation proved that it was possible to obtain
a film having good flaxibility from films having a ratio of com-
position of fluorocarbonpolymer and rubber-like elastic material
in the range of 20/80 - 60/40. However, it was noted that the
coating films as applied showed poor adhesion due to the nature
of the objects and further it was learned that the coating films
were lacking in the desired low frlction characteristic which
derived from a softnes~ of the films.
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The inventor has found tha-t it is possible to produce a
compound for coating the surface of an object to create a film which
is self-lubricative as peculiar to fluorocarbonpolymer and which
will flexibly deform itself in elongation, bending and contracting
accordingly and which can restore itself to its original state after
the relieving of the deformation. The method of manufacture of the
compound is to add the proper ratio of a polymer as a third ingre-
dient to the aforementioned two element compound which consists
. .
of fluorocarbonpolymer and rubber-like elastic material. The
third ingredient is a polymer which can form by itself a hard or
semi-hard film with strong adhesive attachment to the object on
which it is applied and which has the characteristic of compatability
with the rubber-like elastic material.
The coated film formed on the surface of an object by the
two element compound consisting of a fluorocarbonpolymer and a
rubber-like elastic material was compared with the film of the
three element compound of this invention. It was recognized that
both of them have a flexibility suitable for practical use, however,
- it was noted clearly that the adhesive attachment to the object
and the self-lubricating capacity of the latter was far superior
to that of the former.
The fluorocarbonpolymer used as a principal ingredient of
the compounds relating to this invention shall be single or mixed
material of polymers such as PTFE, FEP, E-TFE or a tetrafluoroethy-
lene-alkylvinyleather copolymer which are mechanically pulverized
into grain with diameter less than 5 mu or organosol as specified
in the said U.K. Patent No. 1,064,840 and all of the above polymers
have the characteristic of self-lubrication. The rubber or rubber-
like elastic material to be used as an element of this invention
shall be any material soluble by an organic solvent which can form
an adhesive and homogenous film on the surface of the object after
being coated thereon and dried.
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` Suitable adhesive and rubber-like elastic materials for the
- above purpose, are synthetic rubbers such as nitrile rubber, chloro~
prene rubber and copolymer of ethylene-vinyl-acetate or polyurethane
rubber, however, the best of all for this invention is the soft
polyurethane rubber which excels the others in mechanical application
and possesses properties of resistance to oil, heat, abrasion and
has the strongest tearing strength among all kinds of elastic
rubber-like materials as well as viery good adhesive attachment to
a wide range of materials. It is particularly preferable to use
thermoplastic polyurethane rubber which is readily soluble with
organic solvent.
The material to be used for the bonding reinforcing resin
(element III) of this invention mus-t be selected from materials
which can be absolutely or partially soluble with the element II,
. !
viz., the rubber-like elastic material. For example, when using
soft polyurethane rubber as element II, the material to be combined
with it as element III shall be selected from thermosetting or
cold-setting epoxy resins, thermoplastic resin~ of the acrylic
group, especially polymethyleacrylate, polymethylemetaacrylate and
hard or semi-hard urethane which is usually called a Polyurethane
Paint or a Polyurethane Binding Agent.
` In the case of using nitrile rubber of chloroprene rubber
as element II, phenol resin should be used as element III. The
ratio of ingredients of the coating compounds of this invention
differs depending upon the purpose of use, but usually the ratio of
fluorocarbonpolymer I, the rubber-like elastic material II and
the adhesive strength reinforcing agent III, which is absolutely
or partially soluble with II, is (I)/(II)~(III) = 20/80 - 80/20 and
preferably in the range of 30/70 - 60/~0 and the ratio of composition
of (II) and (III~ in the above composition shall be (II)/(III)
95/5 - 30/70 and preferably in the range of 90/10 - ~0/60.
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The coating compound relating to this invention is produced
by mixing and dispersing uniformly fine powder or organosol of
fluorocarbonpolymer I, rubber-like elastic material II and adhesive
strength reinforcing agent III in an organic solvent and usually
. .
these ingredients and the solvent can be dissolved and dispersed
to an ideal condition by mixing them in a ball mill or pebble mill
for minimum of 30 minutes to a maximum of 72 hours.
The compouna of this invention can form a coating film by
coating the object using a normal process and the~ drying the
coating in air or by heating, If needed, the object can be heated
under a predetermined temperature for some hours in a range which
will not deteriorate the object. The film adheres well to rubber or
rubber-like high molecular weight objects and possesses a solidity
not destroyed by the effect o~ elongation, bending and contraction
caused by external forces. It has a low friction and non-adhesive
characteristics such as are peculiar to fluorocarbonpolymers.
Quoted hereunder are several examples of practical experiments
relating to this invention.
Practical Experiment No. 1.
(1) Polyurethane Rubber Solution.
Pellets (125 parts in weight) of thermoplastic urethane
rubber of the polyester group as manufactured by Nippon Elastollan
Industries, Ltd, with the trademark "ELASTOLLAN E185PMOO" (an
adipate type thermoplastic polyurethane) having Shore Hardness 85
and 87~5 parts in weight of tetrahydrofrun (to be abbreviated as
THF hereunder) are mixed and agitated in a proper agitator at
normal temperature to produce a homogenous rubber solution, The
viscocity of the solution at temperature 25C is 30-50 CPS,
(2) Fluorocarbon Organosol
35% by weight o~ mixed organosol solution composing of
PTFE/FEP=5/95 produced by the method explained in the Japanese
Patent Gazette No, SHO 48 175~8 was applied,
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(3) Adhesive Strength ~einforcing Agent.
Polyurethane Binding Agent Solution trademarked "NIPPOLAN -
2304" as manufactured by Nippon Polyurethane Industries, Ltd., was
used. This binding agent is a solution of 35~ by weight of
methylethylketon and its viscosity at temperature 24 C is 20,000 -
40,000 CPS.
(4) The manufacture of the compound for the coating film con-
taining fluorocarbon and the result of the experiment.
672 g of the soft thermoplastic polyurethane rubber solution
(1), 400 g of the fluorocarbon organosol (2) and 1~0 g of
"NIPPOLLAN" (3) were simultaneously put into a pot mill of 2 liter
capacity and agitated to mix them for 48 hours at 110 r.p.m~ at 23 C
The mix was then taken out of the pot mill and filtered
through a 120 mesh wire gauze.
Solid bod;es included in the compound were 22.75% weight.
The above solution containing fluorocarbon for coating was sprayed
onto the surface of a plate in size of 50 mm x 100 mm x 2 mm made
of non-adhesive PTFE and dried in air and further baked in an
electric oven for 30 minutes at 150 C. Then a film of 100 mm thick-
ness was peeled away from the plate and the result of the testingmade in compliance with the Japanese standard of JIS K-6301
showed good toughness and extending properties with a high percen-
tage of elongation such as 380 - 420%.
The same coating compound was sprayed onto the surface of
an aluminum plate and a plate of thermoplastic urethane rubber as
manufactured by Mippon Elastollan Industries, Ltd~, with the trade-
mark "ELASTOLLAN E195FNAT" having a Shore ~ardness 95 (size of
each plate 50 mm x 100 mm x 2 mm) and they were dried in air and
further baked in an electric oven for 30 minutes at 150 C. Both
plates showed very good adhesion and flexibility of the coating films
on them. The results of tests on coeffieient of friction, resistance
against abxasion, bending, etc., of the film prepared for the above
practical experiment and other films of different material are
shown and compared in the list below.
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. , _. .. ._
TESTED
\ MATERIAL COMPOUND OF prrFE Nylon 6 Polyurethane
TEST \ EXPERIMENT I Rubber
ITEM \ Shore Hardness
... _ _ , ~ . .. ___ . .. __ ~,
Coefficient of Friction
0.055-0.03 0.03 0.07 0.34
__ . __ .. ... _ . . . _ . . _I Taber System Abrasion
Test (mg) 6 17 7.4 2.4
... ~ ..... ___.__ .
Numbers of Bending more than more than
Repeated Until Cracking
of Film 200,000 _ _ 200,000
. ... .. ~.. ,__ , . _~_~_ _~_
Peel Off Aluminum
Strength Plate 5.6 _ _ _
(25C) ~595 pOly- , _ _ .
~kg/25 mm) urethane CAN NOT
Plate PEEL OFF
~L! ~ _ ~ .... ~ .. _ _
Coefficient of Friction: Measured by Bowden, Leben Type tester
with 8 mm dia. steel ball at speed of 0.23 cm/sec. for
load 1 kg.
Taber Abrasion Test: Tested by Taber Abrasion Tester indicated mg
value after 1,000 revolutions using an Abrastion Wheel No.
CB 17 for load 1 kg.
Numbers of Bending: Tested on a Demattia Flexing Tester by making
a bend 300 times per minute from 78 mm maximum stroke to
22 mm minimum stroke at 25 C and indicated by numbers of
bending until the point of time when a crack started on
the specimen.
Peel Off Strength: Tested in compliance with JIS K-630L.
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Practical Experiment No. 2
(1) Polyurethane Rubber Solution.
20 parts by weight of "ELASTOLLAN E185MPOO" as specified
in Practical Experiment 1 and 80 parts by weight of THF were mixed
and agitated to make the solution. The viscosity of the solution at
24 C is 100-120 CPS. This solution is indicated as Urethane Rubber
in the list below~
(2) Fluorocarbon Organosol,
A 35% by weight mixed organosol solution of PTFE-FEP = 10/90
was produced by the method explained in the Japanese Patent Gazette
No. S~O 18-17548,
(3) Adhesive Strength Reinforcing Agent.
. .
Epoxy resin trademarked "ARALDITE AW106" and hardener
trademarked "HV953U" both as manufactured by CIBA-GEIGY, Switzerland,
are dissolved together in a mixed solvent of THF and methylisobuth-
ylketon.
.. . ... _ _, ........... .. . . .
Specimen No.
INGREDIENT 1 2 3
--- . - ...... _ _ t~
VRETHANE RUBBER SOLUTION 320 (g) 380 (g) 450 (g)
ORGANOSOL 360 360 350
. .......... ~. . .. ''
AW 106 56 ~ 45 28
~ ~ . ,
HV953U 44 35 22
THF 150 120 100
__.____ ~ ............ __ ............ __
_ _ 60 50 40 ,
The ingredients in the above ]ist were put into a ball mill
pot of 2 liter capaaity and mixed for 72 hours at ll0 r,p.m. at 25 C
and then the content was taken out of the pot and filtered through
a 120 mesh metallic gauze.
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The solid bodies contained in -the cornpound (1) was 29.29%
by weight. Each of the above solutions of fluol:ocarbon containing
compound was sprayed onto the surface of non-adhesive PTFE plates
with dimensions of 50 mm x 100 mm x 2 mm and dried in air and further
baked in an electric oven for 10 minutes at 150 C. Each of the films
of about 100 mu thickness was then peeled away from the plate and
showed characteristics of great elongation and bending strength.
Each of the compounds was also sprayed on the surface of
an aluminum plate and a nitrile rubber plate of Shore Hardness 70
10 and dried in air and further baked in an electric oven for 10 minutes
at 150 C has shown its good adhesion and flexibility with the object.
The result of test on coefficient of friction, abrasion
resistance, peel off strength and elongation of films taken from each
coated plate are shown in the list below.
. ~ . . _ __
~ ~ 1_ 2 3 _
Friction 0.04-0.0450.045-0.048 0.045-0.05
.. - _ ___ ___ ~
Taber Abrasion (mg) 12 8 6
-- -- .. ,_.. ,... - - ~ _ .
Elonqation (%) 250 290 320
_ _ . ~_ . __
Peel Off Aluminum 8.0 6.5 4 3
Strength ! __ _ ___~ __
(25C) NiStri01e 7.2 5.8 4,3
(kg/25mm) Rubber _ .
. ... _ _
Practical Experiment No. 3
100 g of chloroprene rubber (manufactured by Toyo Soda
Industries, Ltd., with the trademark "SKYPRENE G-40" was dissolved
in a mixed solvent consisting of 400 g of n-hexanon and 400 g of
20 ethyl-aceta-te and then to this ~;olution was added 100 g of fine
powder FEP (manufac-tured by Daikin Indus-tries, Ltd. with the trade-
mark "NEOFLON N-10'), 30 g of alkyl-l?henol r~sin (manufactured by
Hitachi Chemical Industries, Ltd. wi.-th the trademark "~IITANOL 1501"),
... .
t ~,l -10-
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`valac type phenol resin synthesized from alkyl phenol) and ~, g
of magnesium oxide and the mix-ture was put into a ball mill pot of
2 liter capacity and operated for 48 hours at llO r.p.m. at 23 C.
The content of the ball mill pot was taken out after the
completion of the operation and was then filtered through a 120 mesh
metallic gauze.
The solid bodies contained in the mixed solution was 16.26
weight %.
The enamel produced as described above was sprayed on the
surface of plates in size of 200 mm w. x 200 mm 1. x 2 mm t. one of
which is made of vulcanized chloroprene rubber and the other is made
of nitrile rubber having Shore Hardness 70 . These coated plates were
dried in air and further baked in an electric oven for 30 minutes at
150 C. Either of the plates showed good adhesion of the enamel and
excellent flexibility of the coated film with the object.
The result of the tests made on the coated films sprayed
on the above plates is shown in the list below.
. ......... _ .. ,
~ SPECIMEN FILM TAKEN FROM FILM TAKEN FROM
TEST ~ CHLOROPRENE NITRILE RUBBER
ITEM ~ P~BBER PLATE PLATE
.. ~ ~
Coefficient of Friction *
0.06 0.06
. -- .... .
NUMBERS OF BENDING more than more than
(crack starting) lO,OOO lO,OOO
... .
PEEL OFF STRENGTH CAN'T PEEL AWAY CAN'T PEEL AWAY
(25 C) (kg/25 mm)
. ~ . .
* Load 200 g
Practical Experiment No._4
90 g of nitrile rubber (manufactured by Nihon Zeon Co., Ltd.
with trademark "E~YCAR 1042") was dissolved in a mixed solvent of 900 g
of methyl-ethyl-keton and lOO g of toluene to this solution was added
130 g of fine powder PTFE (manufactured by I.C.I. I.td., Enyland, with
the trademark "L-169") and 40 g of degenerated phenol resin (manu-
factured by Durez Co. with ~e trademark "DUREZ 12687") and the
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mixture was put into a ball mill pot of 2 liter Capacity and
operated for 48 hours With 110 r.p.m. at 23 C.
The content waS taken out after completion of mixing
operation and filtered through a 120 mesh metallic gauze.
Solid bodies contained in the compound was 23.63% by weight.
The enamel of the compound was sprayed on the surface of
plates of vulcanized synthetic rubber as described in the Practical
Experiment 3 and dried in air and further baked in an electric oven
for 30 minutes at 150C and each of them showed very good adhesion
~-0 of the enamel to the object and excellent flexibility itself.
The results of the test made on the coated film on the
panels as above are shown in the list below.
, __~ . . _
SPECIMEN FILM ON CHLORO- FILM ON NITRILE
TEST PRENE RUBBER RUBBER PLATE
ITEM PLATE
~ , ..
COEFFICIENT OF FRICTION *
0.05 0.05
,. _ _ .. ,.._., ... ___ ___
NUMBERS OF BENDING more than more than
(crack starting) 10,000 10 000
~ ~ . ~
PEEL OFF STRENGTH
(kg/25 mm) 6.2 can't peel off
~ ~_
* Load 200 g
While the invention has been described hereinabove in its preferred
forms, it is desired to be protected for all forms coming within the claims
hereinbelow.
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