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