U.S. patent application number 14/852585 was filed with the patent office on 2016-06-16 for osp-containing composition for automotive brake fluid.
The applicant listed for this patent is Hyundai Motor Company, Kukdong Jeyen Company Limited. Invention is credited to Chang Yeol Jo, Ga Eun Lee, Hong Ki Lee, Sung Uk Lee, Jae Yoon Park.
Application Number | 20160168502 14/852585 |
Document ID | / |
Family ID | 56082141 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160168502 |
Kind Code |
A1 |
Lee; Ga Eun ; et
al. |
June 16, 2016 |
OSP-CONTAINING COMPOSITION FOR AUTOMOTIVE BRAKE FLUID
Abstract
Disclosed is a composition of brake fluid for a vehicle. The
composition includes an amount of about 30 to 60 wt % of a boric
ester compound; an amount of about 30 to 60 wt % of alkylene glycol
alkyl ether; and an amount of about 0.05 to 10 wt % of oil soluble
polyalkylene glycol (OSP), based on the total weight of the
composition. Accordingly, the OSP-containing composition for brake
fluid may decreases a moisture absorption amount of the brake fluid
in the air and maintain a high boiling point of the brake fluid for
a long period of time, thereby extending a period for changing
brake fluid and improving corrosion prevention performance, metal
wear prevention performance, and an operation of a master
cylinder.
Inventors: |
Lee; Ga Eun; (Seoul, KR)
; Lee; Sung Uk; (Boryeong, KR) ; Park; Jae
Yoon; (Seoul, KR) ; Jo; Chang Yeol; (Busan,
KR) ; Lee; Hong Ki; (Pyeongtaek, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company
Kukdong Jeyen Company Limited |
Seoul
Busan |
|
KR
KR |
|
|
Family ID: |
56082141 |
Appl. No.: |
14/852585 |
Filed: |
September 13, 2015 |
Current U.S.
Class: |
508/185 |
Current CPC
Class: |
C10M 2219/09 20130101;
C10M 2209/1045 20130101; C10M 2207/026 20130101; C10M 2227/061
20130101; C10M 2215/042 20130101; C10M 2215/223 20130101; C10M
2207/046 20130101; C10M 2209/1075 20130101; C10N 2040/08 20130101;
C10M 2215/04 20130101; C10M 111/04 20130101; C10M 2209/1085
20130101; C10M 2209/1045 20130101; C10M 2209/1085 20130101 |
International
Class: |
C10M 141/06 20060101
C10M141/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2014 |
KR |
10-2014-0181772 |
Claims
1. A composition for automotive brake fluid, comprising: an amount
of about 30 to 60 wt % of a boric ester compound; an amount of
about 30 to 60 wt % of alkylene glycol alkyl ether; and an amount
of about 0.05 to 10 wt % of oil soluble polyalkylene glycol (OSP),
all the wt % based on the total weight of the composition.
2. The composition of claim 1, wherein the oil soluble polyalkylene
glycol (OSP) is a polymer including a repeating structure
represented by the following Chemical Formula: ##STR00003## wherein
R.sup.1 and R.sup.2 are same or different, and each is
independently a linear or cyclic alkyl group having at least two
carbon atoms; and m and n are each independently an integer of 10
or greater.
3. The composition of claim 1, wherein the alkylene glycol alkyl
ether is at least one selected from the group consisting of
triethylene glycol monomethyl ether, triethylene glycol monobutyl
ether, polyethylene glycol monomethyl ether, polyethylene glycol
monobutyl ether, and diethylene glycol monobutyl ether.
4. The composition of claim 1, further comprising: an amount of
about 0.1 to 2.0 parts by weight of a metal corrosion inhibitor and
an amount of about 0.1 to 2.0 parts by weight of an antioxidant,
based on 100 parts by weight of the composition.
5. The composition of claim 4, wherein the metal corrosion
inhibitor comprises an amount of about 0.05 to 1.5 parts by weight
of an alkylamine based metal corrosion inhibitor and an amount of
about 0.05 to 0.5 parts by weight of a triazole based metal
corrosion inhibitor, based on 100 parts by weight of the
composition.
6. The composition of claim 5, wherein the alkylamine based metal
corrosion inhibitor is at least one selected from the group
consisting of methylamine, dibutylamine, triethylamine,
triethanolamine, and cyclohexylamine.
7. The composition of claim 5, wherein the triazole based metal
corrosion inhibitor is at least one selected from the group
consisting of benzotriazole, mercaptobenzotriazole, and
tolyltriazole.
8. The composition of claim 4, wherein the antioxidant is
3,5-di(tert-butyl)-4-hydroxytoluene (BHT).
9. A vehicle that comprise a composition of claim 1.
10. The vehicle of claim 9, wherein the composition is used as a
brake fluid.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on and claims the benefit of
priority to Korean Patent Application No. 10-2014-0181772, filed on
Dec. 16, 2014 in the Korean Intellectual Property Office, the
disclosure of which is incorporated herein in its entirety by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a composition for a brake
fluid for a vehicle. The composition may decrease a moisture
absorption amount of the brake fluid in the air and maintain a high
boiling point of the brake fluid for a long period of time, such
that a period for changing break fluid change may be extended and
corrosion prevention performance and metal wear prevention
performance may be improved. Particularly, the composition includes
oil soluble polyalkylene glycol (OSP) at a predetermined content
ratio with respect to a mixed solvent which comprises boric ester
and alkylene glycol alkyl ether at a predetermined content
ratio.
BACKGROUND
[0003] A brake fluid of a vehicle plays an important role of
accurately transferring pressure generated in a master cylinder to
a wheel cylinder. When a problem occurs in this process, brake
responsibility may be deteriorated. Indeed, the brake fluid as
described above may require several essential factors associated
with chemical and physical properties thereof. Among them, a high
equilibrium reflux boiling point (ERBP) may be a primary essential
factor. For example, the brake fluid itself is a liquid that may
not boil or evaporate at normal condition, but since a high
temperature or heat is generated during a braking operation, the
brake fluid may boil depending on the situation. If the brake fluid
boils, the pressure of the master cylinder may not be accurately
transferred, such that stable braking force may not be applied.
Further, a temperature of frictional heat generated at the time of
frequently using a disk brake in a brake system is about
800.degree. C., and brake fluid may be oxidized by the heat,
thereby causing safety problems and deteriorating corrosion
prevention performance.
[0004] Further, a high wet equilibrium reflux boiling point may be
another essential factor. The brake fluid as being a liquid may
require a low hygroscopic property, however, it is also important
that a boiling point is not decreased even though the brake fluid
absorbs substantial moisture. For instance, when the boiling point
is decreased due to moisture absorption of the brake fluid in the
air, a vapor lock phenomenon may be generated, thereby causing a
safety accident.
[0005] In addition, a viscosity change rate of the brake fluid
should not vary substantially in a wide temperature range. Further,
a metal corrosion inhibitor, an oxidation stabilizer, and the like,
may be added to the brake fluid in order to prevent corrosion of
various metals present in a brake device to allow the brake device
to have durability.
[0006] As generally used brake fluid for vehicles, DOT-3 brake
fluid including a glycol ether compound as a sole solvent, and
DOT-4 brake fluid including about 30 to 60 wt % of a boric ester
compound have been mainly used. Since the DOT-3 brake fluid
includes only the glycol ether compound having a low molecular
weight, the brake fluid may absorb moisture in the air at the time
of being used for a long period of time to cause a vapor lock
phenomenon while decreasing a wet boiling point, thereby generating
an accident due to brake inability, and long-term metal corrosion
prevention performance may be deteriorated. Further, since at least
DOT-4 brake fluid includes the boric ester compound, an equivalent
reflux boiling point and a wet boiling point may be elevated, such
that safety may be improved as compared to the DOT-3 brake fluid.
However, when moisture contacts with the brake fluid, the boric
ester compound therein may be hydrolyzed and boric acid may be
precipitated, which deteriorates physical properties as the brake
fluid and generates foreign materials. As such, in order to prevent
boric acid from being precipitated, an amine or silane based
stabilizer may be added thereto and then used. Accordingly, a novel
composition which can prevent moisture absorption of brake fluid
and prevent a decrease in a wet boiling point due to moisture
absorption has been still in demand.
[0007] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and therefore it may contain information that does not
form the prior art that is already known in this country to a
person of ordinary skill in the art.
SUMMARY
[0008] In preferred aspect, the present invention provides a
composition for a brake fluid of a vehicle. The composition may
decrease a moisture absorption amount of the break fluid in the air
and maintain a high boiling point thereof during a long period of
time, thereby securing a smooth operation of a master cylinder,
extending brake fluid change period and improving corrosion
prevention performance and metal wear prevention performance.
[0009] The present inventors have studied in order to solve the
above-mentioned problems according to the related art, and as a
result, the present inventors have found that when oil soluble
polyalkylene glycol (OSP) is mixed with a DOT-4 brake fluid in the
related art, an moisture absorption amount of brake fluid in the
air was decreased as compared to a conventional brake fluid.
[0010] According to an exemplary embodiment of the present
invention, a composition for brake fluid of a vehicle may comprise
an amount of about 30 to 60 wt % of a boric ester compound; an
amount of about 30 to 60 wt % of alkylene glycol alkyl ether; and
an amount of about 0.05 to 10 wt % of oil soluble polyalkylene
glycol (OSP), all the weight % (wt %) based on the total weight of
the composition.
[0011] The oil soluble polyalkylene glycol (OSP) may be a polymer,
and particularly, the polymer may include a repeating structure
represented by the following Chemical Formula 1.
##STR00001##
[0012] In Chemical Formula I, R.sup.1 and R.sup.2 , may be same or
different, and each is independently a linear or cyclic alkyl group
having at least two carbon atoms; and m and n are each
independently an integer of 10 or greater.
[0013] The alkylene glycol alkyl ether may be at least one selected
from the group consisting of triethylene glycol monomethyl ether,
triethylene glycol monobutyl ether, polyethylene glycol monomethyl
ether, polyethylene glycol monobutyl ether, and diethylene glycol
monobutyl ether.
[0014] The composition for the brake fluid may further comprise an
amount of about 0.1 to 2.0 parts by weight of a metal corrosion
inhibitor and an amount of about 0.1 to 2.0 parts by weight of an
antioxidant, based on 100 parts by weight of the composition of
brake fluid. Preferably, the metal corrosion inhibitor may include
an amount of about 0.05 to 1.5 parts by weight of an alkylamine
based metal corrosion inhibitor and an amount of about 0.05 to 0.5
parts by weight of a triazole based metal corrosion inhibitor,
based on 100 parts by weight of the composition of brake fluid. In
particular, the alkylamine based metal corrosion inhibitor may be
at least one selected from the group consisting of methylamine,
dibutylamine, triethylamine, triethanolamine, and cyclohexylamine,
and the triazole based metal corrosion inhibitor may be at least
one selected from the group consisting of benzotriazole,
mercaptobenzotriazole, and tolyltriazole.
[0015] Preferably, the antioxidant may be
3,5-di(tert-butyl)-4-hydroxytoluene (BHT).
[0016] Further provided are vehicles that comprise the composition
as described herein. In particular, the composition may be used as
a brake fluid in the vehicles.
[0017] Other aspects of the invention are disclosed infra.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects, features and advantages of the
present disclosure will be more apparent from the following
detailed description taken in conjunction with the accompanying
drawings.
[0019] FIG. 1 is a graph illustrating moisture absorption amounts
(%) of DOT-4 brake fluid in the air using compositions for brake
fluid of Examples 1 to 6 according to exemplary embodiment of the
present invention and Comparative Examples 1 and 2 during time
course.
[0020] FIG. 2 is a photograph showing appearance of compositions
for the brake fluids based on DOT-4 after performing a four ball
wear prevention test of brake fluid according to exemplary
embodiments of the present invention.
DETAILED DESCRIPTION
[0021] It is understood that the term "vehicle" or "vehicular" or
other similar term as used herein is inclusive of motor vehicles in
general such as passenger automobiles including sports utility
vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and
the like, and includes hybrid vehicles, electric vehicles, plug-in
hybrid electric vehicles, hydrogen-powered vehicles and other
alternative fuel vehicles (e.g. fuels derived from resources other
than petroleum). As referred to herein, a hybrid vehicle is a
vehicle that has two or more sources of power, for example both
gasoline-powered and electric-powered vehicles. The terminology
used herein is for the purpose of describing particular exemplary
embodiments only and is not intended to be limiting of the
invention. As used herein, the singular forms "a", "an" and "the"
are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. As
used herein, the term "and/or" includes any and all combinations of
one or more of the associated listed items.
[0022] Unless specifically stated or obvious from context, as used
herein, the term "about" is understood as within a range of normal
tolerance in the art, for example within 2 standard deviations of
the mean. "About" can be understood as within 10%, 9%, 8%, 7%, 6%,
5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated
value. Unless otherwise clear from the context, all numerical
values provided herein are modified by the term "about."
[0023] The present invention relates to a composition of a brake
fluid which may decrease a moisture absorption amount of brake
fluid in the air, decrease metal friction, and have improved
corrosion prevention performance.
[0024] In an exemplary composition for the brake fluid according to
the present invention, a mixed solvent in which boric ester and
alkylene glycol alkyl ether are mixed at a predetermined content
ratio may be used, and OSP may be included therein at a
predetermined content ratio. Additionally, the composition for
brake fluid may further contain a metal corrosion inhibitor or an
antioxidant.
[0025] Each of the ingredients of the composition for brake fluid
according to various exemplary embodiment of the present invention
will be described below in detail.
[0026] The composition for brake fluid may include the mixed
solvent which is prepared by mixing boric ester and alkylene glycol
alkyl ether at a predetermined content ratio. That is, based on the
total weight (100%) of the composition for brake fluid, an amount
of about 30 to 60 wt % of boric ester and an amount of about 30 to
60 wt % of alkylene glycol alkyl ether can be mixed.
[0027] Boric ester contained in the mixed solvent may be used in
order to prevent a boiling point from being decreased by moisture
absorption, and boric ester may be included in a content range of
about 30 to 60 wt % based on the total weight (100%) of the
composition for brake fluid. When the boric ester is included in
less than the above-mentioned range, sufficient desired effect may
not be obtained, and when the boric ester is included in greater
than the above-mentioned range, manufacturing cost may be
increased, and boric acid may be precipitated.
[0028] The alkylene glycol alkyl ether included in the mixed
solvent may be used in order to have a lubrication operation in a
cylinder and a piston in a brake system to be smoothly performed.
Examples of the alkylene glycol alkyl ether may be, but not limited
to, triethylene glycol monomethyl ether, triethylene glycol
monobutyl ether, polyethylene glycol monomethyl ether, polyethylene
glycol monobutyl ether, diethylene glycol monobutyl ether, and the
like. Preferably, the alkylene glycol alkyl ether may be included
in a content range of about 30 to 60 wt % based on the total weight
(100%) of the composition for brake fluid.
[0029] Further, the composition for brake fluid may comprise OSP in
addition to the mixed solvent, and may further contain the metal
corrosion inhibitor or the antioxidant.
[0030] The oil soluble polyalkylene glycol (OSP) may be used in
order to decrease the moisture absorption amount of the brake fluid
in the air and maintain the high boiling point of the brake fluid
for a long period of time. As such, the OSP may be an essential
ingredient used to extend brake fluid change period and improve
corrosion prevention performance and metal wear prevention
performance. In particular, the OSP may be a polymer having a
repeating structure represented by the following Chemical Formula
1.
##STR00002##
[0031] In Chemical Formula I, R.sup.1 and R.sup.2 are same or
different, and each is independently a linear or cyclic alkyl group
having at least two carbon atoms; and m and n are each
independently an integer of 10 or greater.
[0032] The OSP may be included in the composition in a content
range of about 0.05 to 10 wt % based on the total weight (100%) of
the composition for brake fluid. When the content of OSP is
substantially less than the above-described content, sufficient
effect of decreasing the moisture absorption amount may not be
obtained. When the content is substantially greater than the above
described content, since OSP has a property of significantly
swelling styrene-butadiene rubber (SBR) or ethylene-propylene diene
monomer (EPDM) rubber, this rubber may be excessively swelled, such
that a volume of EPDM in the master cylinder may be significantly
increased, thereby hindering a piston operation. When the DOT-4
brake fluid is prepared, OPS may be used in a content range of
about 0.05% to 10% in a brake fluid in order to have an EPDM rubber
cup of the master cylinder in the brake system to smoothly perform
a piston operation. It was confirmed that when an amount of about
0.05 to 10% of OSP, e.g. a polyalkylene glycol group, is added, the
moisture absorption amount of the brake fluid in the air was
significantly different as compared to the case of adding a general
polyalkylene glycol in addition to lubrication performance which is
a basic function of the polyalkylene glycol. Further, when the OSP
is added in greater amount than the above-described content, OSP
may hinder the piston operation as described above.
[0033] Since pipes made of metal materials such as the master
cylinder, a wheel cylinder, and the like, may be corroded by boric
ester and alkylene glycol alkyl ether in the mixed solvent, the
metal corrosion inhibitor may be suitably used in order to prevent
corrosion as described above. Preferably, a mixture of an
alkylamine based and triazole based metal corrosion inhibitors may
be used. Particularly, the alkylamine based metal corrosion
inhibitor, which is an amine compound substituted with 1 to 3
linear, branched, or cyclic alkyl groups having 1 to 10 carbon
atoms, may be, but not limited to, at least one selected from the
group consisting of methylamine, dibutylamine, triethylamine,
triethanolamine, and cyclohexylamine. The triazole based metal
corrosion inhibitor may be, but not limited to, at least one
selected from the group consisting of benzotriazole,
mercaptobenzotriazole, and tolyltriazole.
[0034] The metal corrosion inhibitor may be included in a content
range of about 0.1 to 2.0 parts by weight based on 100 parts by
weight of the composition for brake fluid. When the content of the
metal corrosion inhibitor is substantially less than the above
described content, sufficient effect of preventing corrosion may
not be obtained, and when the content thereof is substantially
greater than the above described content, loud noise may be
generated at the time of operating the master cylinder in the brake
system. Preferably, the metal corrosion inhibitor may be a mixture
of the alkylamine based metal corrosion inhibitor in an amount of
about 0.05 to 1.5 parts by weight and the triazole based metal
corrosion inhibitor as the metal corrosion inhibitor in an amount
of about 0.05 to 0.5 parts by weight, all the weight parts based on
100 parts by weight of the composition for brake fluid.
[0035] The antioxidant may be included in the composition to
prevent oxidation, and the antioxidant may be at least one selected
from general antioxidants used in the related art. Preferably, the
antioxidant may be, but not limited to,
3,5-di(tert-butyl)-4-hydroxytoluene (BHT).
[0036] The antioxidant may be included in a content range of about
0.1 to 2.0 parts by weight based on 100 parts by weight of the
composition for brake fluid. When the content of the antioxidant is
substantially less than the above-described content thereof,
sufficient effect of preventing oxidation may not be obtained, and
when the content thereof is substantially greater than the
above-described content thereof, loud noise may be generated at the
time of operating the master cylinder in the brake system.
[0037] According to various exemplary embodiments of OSP-containing
compositions for brake fluid, the high boiling point of the brake
fluid may be maintained for a long period of time, and an effect as
an extreme pressure agent may be excellent, such that wear of
surfaces of iron balls may be decreased, and metal corrosion
prevention performance may be improved.
[0038] The present invention as described above will be described
in detail based on the following Example and Experimental Example,
but the present disclosure is not limited thereto.
EXAMPLE
Examples 1 to 6 and Comparative Examples 1 and 2
Preparation of Composition for Brake Fluid Based on DOT-4
[0039] Compositions for brake fluid based on DOT-4 were prepared
using ingredients to have content ratios as illustrated in the
following Table 1.
TABLE-US-00001 TABLE 1 Comparative Comparative Composition Example
1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1
Example 2 Solvent Diethylene Glycol -- -- -- -- -- -- -- --
Polyethylene Glycol 15 15 14 12.5 11.3 10 15 12.5 Monomethyl Ether
Polyethylene Glycol 17.9 17 17 15.5 14.3 14 18 15.5 Monobutyl Ether
Triethylene Glycol 15 15 14 12.5 11.3 10 15 12.5 Monomethyl Ether
Boric Ester Compound 50 50 48 47.5 46.1 40 50 47.5 Metal
Benzotriazole 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Corrosion
Mercaptobenzotriazole 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Inhibitor
Cyclohexylamine 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Dibutylamine 0.7
0.7 0.7 0.7 0.7 0.7 0.7 0.7 Antioxidant 3,5-di(tert-butyl)-4- 0.2
0.2 0.2 0.2 0.2 0.2 0.2 0.2 hydroxytoluene Polyalkylene OSP-32 *
0.1 1 5 10 15 20 Glycol Polyalkylene Glycol 10 Sum 100 100 100 100
100 100 100 100 OSP-32: Ucon .TM. OSP-32 Lubricant (Dow Chemical
Comp.)
[0040] Compositions for brake fluid in which OSP was added to a
composition for DOT-4 brake fluid used according to the related art
while changing a content of the OSP are illustrated in Table 1. In
order to increase the content of OSP, contents of polyethylene
glycol monobutyl ether, triethylene glycol monomethyl ether, and
the boric ester compound in the mixed solvent were decreased as in
Table 1, respectively, and a sum of the decreased content and an
increased content of OSP were the same each other. Further,
comparative Examples 1 and 2 are compositions for DOT-4 brake fluid
according to the related art to which OSP was not added, such that
Comparative Example 1 was a composition not containing polyalkylene
glycol and Comparative Example 2 was a composition containing 10%
of polyalkylene glycol. In the composition of Comparative Example
2, a content of the mixed solvent was decreased as compared to
Comparative Example 1 so as to correspond to the content of added
polyalkylene glycol. An example of OSP-containing compositions for
brake fluid according to the present invention includes the
compositions of Examples 1 to 6 illustrated in Table 1, and the
compositions of Examples 1 to 6 and Comparative Examples 1 and 2
were confirmed through various Experimental Examples described
below.
Experimental Example
Experimental Example 1
Moisture Absorption Amount Test of Each Composition in Air
[0041] After 100 ml of each of the compositions for brake fluid
based on DOT-4 (Examples 1 to 6 and Comparative Examples 1 and 2)
of Table 1 was put into a beaker, the compositions were kept at
room temperature for 15 days and moisture absorption amounts
thereof in the air were compared and observed, as illustrated in
Table 2. A brake fluid before the test was referred to as a novel
solution, and the moisture absorption amount was measured every day
for 15 days during the test, and the results were illustrated in
Table 2.
TABLE-US-00002 TABLE 2 Moisture Absorption Amount (%) of
Composition for Brake Fluid Based on DOT-4 in Air comparative
comparative Date Example 1 Example 2 Example 3 Example 4 Example 5
Example 6 Example 1 Example 2 Novel Solution 0.1 0.1 0.1 0.1 0.1
0.1 0.1 0.1 Day 1 1.3 1.2 1.1 1 0.9 0.9 1.4 1.4 Day 2 2.6 2.4 2.2 2
1.8 1.7 2.7 2.6 Day 3 3.6 3.4 3.2 3 2.6 2.3 3.6 3.7 Day 4 4.6 4.4
4.2 4 3.4 2.9 5 4.9 Day 5 5.6 5.4 5.2 4.9 4.1 3.4 6.1 6.0 Day 6 6.6
6.4 6 5.7 4.7 3.8 7.1 7.1 Day 7 7.6 7.2 6.8 6.3 5.2 4.2 8.1 8.1 Day
8 8.5 8 7.5 6.8 5.6 4.5 9 8.9 Day 9 9.3 8.8 8.2 7.2 6 4.8 9.8 9.9
Day 10 10 9.5 8.8 7.6 6.3 5.1 10.5 10.4 Day 11 10.7 10.2 9.2 7.9
6.7 5.3 11.2 11.1 Day 12 11.3 10.8 9.5 8.2 7 5.6 11.8 11.9 Day 13
11.8 11.3 9.8 8.4 7.2 5.8 12.3 12.2 Day 14 12.2 11.7 10.1 8.6 7.3 6
12.8 12.8 Day 15 12.5 12 10.2 8.7 7.4 6.1 13.2 13.1
Experimental Example 2
Boiling Point Test of Each Composition
[0042] A boiling point of the compositions before testing as
Experimental Example 1 and a boiling point of the brake fluid after
15 days were compared with each other. The following Table 3 is a
table illustrating comparison results of the boiling points of
composition for brake fluid based on DOT-4 of Table 2.
TABLE-US-00003 TABLE 3 Change in Boiling Point of Composition for
Brake Fluid Based on DOT-4 Comparative Comparative Date Example 1
Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example
2 Novel Solution 270.degree. C. 270.degree. C. 270.degree. C.
270.degree. C. 270.degree. C. 270.degree. C. 270.degree. C.
270.degree. C. Day 15 128.degree. C. 130.degree. C. 136.degree. C.
144.degree. C. 148.degree. C. 152.degree. C. 120.degree. C.
120.degree. C.
Experimental Example 3
Four Ball Wear Prevention Test
[0043] As shown above, friction between metals may occur in an
ABS/ESP module among brake system components at the time of
performing a braking operation during driving a vehicle, and at the
time of frequently performing the braking operation, wear
prevention performance may be deteriorated due to metal friction,
such that a brake distance may be increased at the time of
performing the brake operation. As an extreme pressure/wear
prevention test against metal friction of the prepared compositions
for brake fluid based on DOT-4 (Examples 1 to 6 and Comparative
Examples 1 and 2), a four ball wear prevention test according to
ASTM D 4172 standard was performed.
TABLE-US-00004 TABLE 4 Four Ball Wear Prevention Test of
Composition for Brake Fluid Based on DOT-4 Wear Prevention
Comparative Comparative Test Example 1 Example 2 Example 3 Example
4 Example 5 Example 6 Example 1 Example 2 Wear Scar 0.72 0.62 0.57
0.55 0.48 0.46 0.85 0.83 Diameter (mm) Appearance Color Changed
Color Changed Good Good Good Good Color Changed Color Changed of
Brake Fluid into into Light into Black into Black Reddish Brown
Reddish Brown
Experimental Example 4
Appearance Test
[0044] Appearance of each of the compositions for brake fluid of
Table 4 was illustrated in FIG. 2. After performing each of the
tests, when the compositions included the content of OSP less than
the predetermined content or no OSP, colors of the brake fluid were
changed into reddish brown or black, but when the compositions
contained 5 to 20 wt % of OSP, appearance of the brake fluids was
good.
[0045] It may be appreciated from the Experimental Examples 1 to 4
that when the OSP-containing composition for brake fluid was used
according to an exemplary embodiment of the present invention, the
moisture absorption amount (after keeping the brake fluids in the
air for 15 days) was decreased by 0.7% to 7.1% as compared to DOT-4
brake fluids (Comparative Examples 1 and 2) according to the
related art. In addition, the boiling point thereof was highly
maintained by 8.degree. C. to 32.degree. C., and as results of the
wear prevention test, iron balls were less worn. Further, as
results of the appearance test, in the case of the OSP-containing
composition for brake fluid according to an exemplary embodiment of
the present invention, the color was not changed into reddish brown
or black.
[0046] Considering all experimental results, the OSP-containing
composition for brake fluid according to various exemplary
embodiment of the present invention may provide substantially
improved results in all of the Experimental Examples.
[0047] However, according to additional study results of the
present inventors, in Examples 5 and 6 in which the content of the
OSP was included greater than about 10 wt %, since the OSP has a
property of significantly swelling styrene-butadiene rubber (SBR)
or ethylene-propylene diene monomer (EPDM) rubber, the OSP may act
as a factor of hindering a smooth piston operation of an EPDM
rubber cup of a master cylinder. As such, although the OSP provides
excellent moisture absorption prevention performance, high boiling
point maintenance performance, and wear prevention performance as
being included in the composition, the excessive content thereof
was not suitable for the brake fluid.
[0048] The composition for brake fluid according to various
exemplary embodiments of the present invention may decrease the
moisture absorption amount in the air, and have the high boiling
point of the brake fluid to be maintained for a long period of
time, thereby extending the period for a brake fluid change as
compared to the conventional brake fluid which does not include the
OSP. Further, the composition for brake fluid according to various
exemplary embodiments of the present invention may decrease metal
friction and prevent metal corrosion, and thus the master cylinder
of the vehicle may smoothly operate.
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