N990 Thermal Black in Natural Rubber isolation bushings for improved dynamic performance

AEQ-QEG Technico-Commercial meetingNovember 8, 2017

2

What is Thermal Carbon Black?

A niche product (specialty chemical)

Produced by thermal decomposition of the natural gas molecule (CH4)

The largest particle size (100-700nm diameter) carbon black

The lowest structure carbon black

The highest purity carbon black

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140 160

OA

N (

DB

P) A

bsorp

tion

(m

l/1

00

g)

Nitrogen Surface Area (m2/g)

IN

CR

EA

SIN

GS

TU

CTU

RE N650

N990

N550

N539

N660

N774N762

N343

N339

N330

N326

N121

N220 N110

THE CARBON BLACK SPECTRUM

DECREASING PARTICLE SIZE

THERMAX®

vs FURNACE BLACK GRADES

Particle size diameter

4

N660 (60nm)

THERMAX®

vs FURNACE BLACK GRADES

High Structure Moderate Structure Low Structure

N550 N762 N990

5

N660

6

DYNAMIC APPLICATIONS

• Tires

• Motor mounts

• Air springs

• V-belts

• Conveyor belts

• Blow out preventer

• Dynamic seals

• Roll covers

• Shoe soles

• Dynamic mechanical goods

• Bushings

• Shock absorbers

• Hoses

• Bridge bearings

• Foam, sponge compounds

• Innertubes

• Caster wheels

• Sporting goods

• Diaphragms

• Suspension bumpers

• Body mounts

• Vibrations isolators

• Rail pads

• Vacuum tubing

• Wiper blades

• Bladders

• Mats

7

RUBBER VISCOELASTICITY

Rubber exhibits both viscous and elastic properties, allowing for very specialized applications.

“Perfect” spring Rubber Honey

8

HYSTERESIS

Energy is lost in the viscoelastic material as heat – causes heat buildup and accelerates rubber aging

9

HYSTERESIS

Energy is lost in the viscoelastic material as heat – causes heat buildup and accelerates rubber aging

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5 6 7

Str

ess

Load (

kN

)

StrainDisplacement (mm)

10

MEASURED DYNAMIC PROPERTIES – WHAT DO THEY MEAN

Tan delta is indicative of heat buildup, noise transmission, rolling resistance

tan 𝛿 =𝐺′′

𝐺′ =𝑣𝑖𝑠𝑐𝑜𝑢𝑠 𝑚𝑜𝑑𝑢𝑙𝑢𝑠

𝑒𝑙𝑎𝑠𝑡𝑖𝑐 𝑚𝑜𝑑𝑢𝑙𝑢𝑠

Viscous Response

Elastic Response

G’’

G’

δ

11

MEASURED DYNAMIC PROPERTIES – WHAT DO THEY MEAN

Want a low spring ratio

–low 𝐾𝑑 and high 𝐾𝑠

Low dynamic stiffness (𝐾𝑑) is a predictor of vibration isolation performance. Sufficient static stiffness (𝐾𝑠) is required to support a load

Dynamic stiffness and static stiffness

𝑠𝑝𝑟𝑖𝑛𝑔 𝑟𝑎𝑡𝑖𝑜 =𝐾𝑑𝐾𝑠

Surface area

Structure

Sunnicliffe, L. (2017). Carbon black reinforcement of rubber for vibration isolation applications. Presented at: Technical Meeting of Rubber Division, ACS.

12

OBJECTIVES FOR AN IDEAL RUBBER BUSHING

The compound must balance the requirements for static stiffness with minimized dynamic stiffness and hysteresis in order to suppress the frequency of resonance

Reduce tan delta (heat buildup, noise transmission)

Increase static stiffness (mechanical integrity)

Increase processability and cost effectiveness

1

2

3

13

TESTING MATERIAL AND FORMULATIONS

Objective:Evaluate the replacement of N660 with N990 in natural rubber isolation bushings for use in automobiles

Anticipated results:• Increased N990 loading to obtain same hardness• Decreased tensile strength• Increased adhesion between rubber and steel with N990 addition

14

LABORATORY TESTING

Dynamic and static testing

– Tokai Chita Lab

•Tensile strength

•Resilience

•Rheometry

•Dynamic and Static moduli

Dynamic testing

- ESI Lab

•Dynamic and Static Moduli

•Heat buildup upon compression cycles

•Rubber hysteresis

Adhesion testing

- RDAbbott

•Rubber Pull Test (ASTM D429 Method B)

15

FORMULATIONS

Compound # 1 2 3 4 5 6 7 8 9

A-0 B-9.65 C-19.3 D-28.95 E-38.5 F-48.25 G-57.9 H-67.55 I-77.2

Carbon black loading in phr

N660 40 35 30 25 20 15 10 5 0

N990 0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2

Total carbon black loading

40 44.65 49.3 53.95 58.6 63.25 67.9 72.55 77.2

Additional Materials: Natural rubber (100phr), Aromatic process oil (5phr) Antioxidant (1phr), Zinc oxide (5phr)Stearic acid (3phr), Accelerator (0.75phr)Sulfur (2.25phr)

16

HARDNESS – MAINTAINED WITH ADDED N990 LOADING

Compound # 1 2 3 4 5 6 7 8 9

A-0 B-9.65 C-19.3 D-28.95 E-38.5 F-48.25 G-57.9 H-67.55 I-77.2

Carbon black loading in phr

N660 40 35 30 25 20 15 10 5 0

N990 0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2

Total carbon black loading

40 44.65 49.3 53.95 58.6 63.25 67.9 72.55 77.2

Hardness 57 57 57 58 57 58 59 58 58

Hardness after aging

62 62 62 62 63 63 64 63 63

17

TENSILE STRENGTH BEFORE AND AFTER AGING

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2

Str

ength

(M

pa)

N990 loading (phr)

Before aging After aging at 100°C for 3 days

Tensile strength decreases with increasing N990 loading. Effects are less pronounced after aging. This is to be expected when replacing a furnace black with thermal black.

18

TENSILE STRESS BEFORE AND AFTER AGING

Tensile stress is relatively unaffected by N990 loading.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Tensile S

tress (

Mpa)

N990 loading (phr)

100% Elongation

0.0

2.0

4.0

6.0

8.0

10.0

12.0Tensile S

tress (

Mpa)

N990 loading (phr)

200% Elongation

Before Aging After Aging

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Tensile S

tress (

Mpa)

N990 loading (phr)

300% Elongation

19

TENSILE STRESS BEFORE AND AFTER AGING

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Tensile S

tress (

Mpa)

N990 loading (phr)

100% Elongation

0.0

0.5

1.0

1.5

2.0

2.5

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0

9.6

5

19.3

28.9

5

38.6

48.2

5

57.9

67.5

5

77.2

Tensile S

tress (

Mpa)

N990 loading (phr)

200% Elongation

Before Aging After Aging Change

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0

9.6

5

19.3

28.9

5

38.6

48.2

5

57.9

67.5

5

77.2

Tensile S

tress (

Mpa)

N990 loading (phr)

300% Elongation

Tensile stress is relatively unaffected by N990 loading.

20

REBOUND RESILIENCE

67.0

67.5

68.0

68.5

69.0

69.5

70.0

70.5

71.0

71.5

72.0

72.5

0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2

Rebound r

esilie

nce (

%)

N990 loading (phr)

Rebound resilience increases with N990 loading.

21

COMPRESSION SET

20.0

25.0

30.0

35.0

40.0

45.0

50.0

55.0

60.0

0 10 20 30 40 50 60 70 80

Com

pre

ssio

n s

et

(%)

N990 loading (phr)

70℃×1day 100℃×1day

Slight decrease in compression set at elevated temperatures. Compression set does not increase with additional filler loading.

22

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

3 5 7 9 11 13 15

Torq

ue (

lbf)

Time (min)

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

RHEOMETRY – VULCANIZATION PROPERTIES

Slight change in rubber vulcanization characteristics, increased Mooney scorch with increasing N990

N990loading

0 phr 77 phr

23

22.0

23.0

24.0

25.0

26.0

27.0

28.0

29.0

30.0

31.0

32.0

0 10 20 30 40 50 60 70 80

Mooney s

corc

h (

min

) M

ooney v

iscosity

N990 loading (phr)

Viscosity Scorch

MOONEY VISCOSITY AND MOONEY SCORCH

Mooney scorch increases with N990, Mooney viscosity unaffected up to 70phr N990 loading. This allows for high filler loading without a decrease in processing abilities.

24

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.12

0 10 20 30 40 50 60 70 80 90 100

tan d

elta

Frequency (Hz)

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

IncreasingN990 loading

1% DYNAMIC STRAIN

N990loading

0 phr 77 phr

Tan delta decreases with increasing N990

25

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.12

0 10 20 30 40 50 60 70 80 90 100

tan d

elta

Frequency (Hz)

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

IncreasingN990 loading

2% DYNAMIC STRAIN

N990loading

0 phr 77 phr

Tan delta decreases with increasing N990

26

5% DYNAMIC STRAIN

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.12

0 10 20 30 40 50 60 70 80 90 100

tan d

elta

Frequency (Hz)

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

IncreasingN990 loading

N990loading

0 phr 77 phr

Tan delta decreases with increasing N990

27

10% DYNAMIC STRAIN

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.12

0 10 20 30 40 50 60 70 80 90 100

tan d

elta

Frequency (Hz)

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

IncreasedIncreasingN990 loading

N990loading

0 phr 77 phr

Tan delta decreases with increasing N990

28

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0 7.5 15 22.5 30 37.5 45 52.5

Tem

pera

ture

change (

°C)

Time (minutes)A-0 B-9.65 C-19.3 D-28.95 E-38.6 G-57.9 H-67.55 I-77.2

NORMALIZED HEAT BUILD-UP

No correlation

N990loading

0 phr 77 phr

29

NORMALIZED DYNAMIC RATE FALLOFF DURING HEAT BUILD-UP

N990loading

0 phr 77 phr

0.75

0.8

0.85

0.9

0.95

1

0 2000 4000 6000 8000 10000 12000 14000

Dynam

ic S

tiffness K

d(N

/mm

)

Cycles

A-0 B-9.65 C-19.3 D-28.95 E-38.6 F-48.25 G-57.9 H-67.55 I-77.2

Dynamic stiffness (Kd) decreases with N990 loading

30

1

1.2

1.4

1.6

1.8

2

2.2

0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2Dynam

ic t

o S

tatic S

pri

ng R

atio

N990 Loading (phr)

0.2% ds (Chita lab) 1% ds 2% ds 5%ds 10%ds

SPRING RATIO

Decrease spring ratio with increased N990 loading. A lower spring ratio indicates improved dynamic properties

𝐾𝑑𝐾𝑠

31

PEEL ADHESION

0

20

40

60

80

100

120

140

160

180

0 9.65 19.3 28.95 38.6 48.25 57.9 67.55 77.2

Maxim

um

load (

lbf)

N990 loading (phr)

All samples failed in the rubber substrate, not by the adhesion of rubber to metal.

32

OVERALL BENEFITS OF USING N990

Good static properties

• Higher rebound resilience

Better dynamic properties

• Lower tan delta

• Lower dynamic to static spring ratio

• Lower dynamic stiffness

Better adhesion

Potential Cost savings

• Higher filler loading of N990 at same hardness value vs smaller particle size carbon blacks

33

GLOBAL ADVANTAGE

34