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Example of CORE-PAD specifications
We offer materials suited to different regions around the world. The specifications given below are an example in accordance with AASHTO that are used for the Southeast and South Asian nations. CORE-PADs can also conform to BS and JIS. You have a choice of CR (Chloroprene Rubber) with high weather resistance or NR (Natural Rubber) with high elongation as raw material and a variety of hardness according to design requirements.
UnitG8
Hardness Hardness
Adhesion
Item UnitG7
Tensile test
Heat Resistance
Compression Set
Ozone
Low Temperature Test
Tensile Strength
Ultimate elongation
Change in hardness
Change in tension
Change in elongation
Compressive strain
Adhesion strength
Brittleness at -40℃
ASTM/Test Condition
50±5 point 57 51
Requirement
D2240
D412
D57370hr×69.9℃
D39522hr×69.9℃
2500
17.2
400
±15
-15
-40
35
psi
MPa
%
point
%
%
%
- -
18.8 19.5
560
2
-3
-11
22
OK
14
OK
670
2
-2
-8
18
OK
13
OK
D1149
100pphm,20%strain,37.7℃±1℃,48hr
D429,B
D746,B No Failure
7 N/mm
No cracksVisual inspection
UnitG8
UnitG7
57 51
- -
18.8 19.5
560
2
-3
-11
22
OK
14
OK
670
2
-2
-8
18
OK
13
OK
MATERIAL
QUALITY CONTROL - Material ControlQuality is not judged by only appearance. Quality control should be made care-fully to ensure quality of bearings. CORE-PADs have gone though various tests conforming to AASHTO and ISO. We have confidence that the quality is good enough to satisfy stringent performance requirements.
(2) Ozone crack testThe occurrence of ozone cracks on the rubber surfaces due to ozone attack have been reported in all over the world. Elastomeric bearings should be necessarily ozone-resistant. We perform verification tests for ozone cracks according to the major specifications and under stricter conditions than those specifications, and develop high-quality ozone-resistant materials.
Ozone crack testing machine
Tensile test
(1) Physical testSkilled engineers in our test laboratory make strict evaluations for basic charac-teristics of rubber material such as hardness, tensile strength, elongation at break, aging characteristics, compression set, and water resistance day after day to ensure stable and high material quality. Only rubber materials that show stable performances will be on manufacturing lines.
Kawakin PAD BEARINGCORE-PAD
TechnicalInformation
1of4Issued 04/13
2-2-7 Kawaguchi, Kawaguchi, Saitama 332-0015 JAPAN |Tel. +81-48-259-1113 Fax. +81-48-259-1137| www.kawakinct.co.jpHanoi Representative Office: 7th Floor, TAF BLDG, 201 Ba Trieu, Hai Ba Trung Dist., Hanoi, VIETNAM |Tel. +84 4 3974 8431
Ozone resistance test
Test results of ozone resistance
0 25 50 75 100 125 150 175 200
20%
50%
75%
100%
Load
ing s
trai
n (
%)
Time (hour)
No cracksDamaged
Kawakin Rubber
Kawakin Rubber
Kawakin Rubber
Kawakin RubberPass
Sev
ere
conditio
n s
etting
International Standard
Japanese Highway New Standard
Other
Other
Other
Other
BreakBreak
BreakBreakPass
Pass
Pass
The test results of vertical stiffness and horizontal stiffness for a total of 245 natural rubber bearings are given below. As it can be seen, 95 percent (Confidence Intervals) of all the measurement data are within a range of ±40% of the design values for vertical stiffness and within ±10% for horizontal stiffness. Conclusively, Kawakin has a high capability for material quality.
Test results of vertical stiffness
Kawakin’ s long-term experience and manufacturing capabilities is the guarantee of rubber material. The figures above represent the results of ozone resistance tests for two types of rubber materials according to International Standard (ISO 22762-2). Both of the test pieces satisfy the minimum standard values required in the Standards. Kawakin’ s test piece is, however, kept sound even under the stricter conditions while the other test piece is not.
0
1000
2000
3000
4000
5000
6000
Ver
tica
l lo
ad (
kN)
0 1 2 3 4 5Vertical displacement (mm)
Double Shear Test
Dunbell test piece
Sheet press machine
Kawakin PAD BEARINGCORE-PAD
TechnicalInformation
2of4Issued 04/13
2-2-7 Kawaguchi, Kawaguchi, Saitama 332-0015 JAPAN |Tel. +81-48-259-1113 Fax. +81-48-259-1137| www.kawakinct.co.jpHanoi Representative Office: 7th Floor, TAF BLDG, 201 Ba Trieu, Hai Ba Trung Dist., Hanoi, VIETNAM |Tel. +84 4 3974 8431