Leveraging
sustainability
while improving
performance

Kuraray Liquid Rubber

Kuraray
LiquidRubberfor long lasting product solutions
Kuraray Liquid Rubber functions as ˝reactive plasticizers˝, they
help reduce Mooney viscosity and facilitate the mixing process.
Features� Transparent
� Colorless� Odorless� Low VOCs

Types
� Liquid Butadiene Rubber (L-BR)
� Liquid Isoprene Rubber (L-IR)
� Liquid Styrene-Butadiene Rubber (L-SBR)� Functionalized: carboxylated, UV-curable,
graft silane
� Bio-based: Liquid Farnesene Rubber (L-FR)

Tires

Rubber goods

Adhesives

Automotive sealants

Kuraray Liquid Rubber

�

Kuraray Liquid Rubber
beyond a reactive plasticizer
MW

1,000,000

NR, SBR

Rubber100,000
10,000Benefits:

Kuraray Liquid Rubber

� Plasticizing effect� Enhanced properties
� Improved final product shelf-life

1,000
100

Process Oil
Liquid Polybutene

Plasticizer0
Depending on molecular weight (MW), Kuraray Liquid Rubber
can act as rubber replacement or a reactive plasticizer.

Bleeding

Benefits:

Process Oil� Co-vulcanizable with solid rubber
� Significant reduction in migration
� Reduces processing time

Cross link
point

Kuraray Liquid Rubber
Kuraray Liquid Rubber is cross-linkable with base rubber and acts like aprocess oil, but does not bleed.

Significant performance and environmental
advantages with Kuraray Liquid Rubber
Mooney, Electric (Index)
110

Mooney Viscosity (130˚C)
Electricity consumption

105

Benefits:� Reduces electric power consumption
� Lower processing cost
� Better sustainability performance (less energy)

100

80
0

5

10

15

L-IR-50 Parts
Formulation
NR (STR20) 100 - 85, L-IR-50 0 - 15, CB (N330) 70, TDAE
5, Vulcanization, Antioxidant ZnO (5), Stearic Acid (2),
AO 6C (1), AO RD (1), Phenol resion (10), HDOT20 (4),Accelerator NS (1.7), HMT (1)

25

6

24

5

Good

85

"E' at 25C˚ (MPa)

90

23

4

22

3

21
20

2
Carbon black dispersion
Method: ISO11345-C

0

5

10

L-IR-50 parts

1
15

CB Dispersion

Dynamic
Dispersion
Dynamic viscoelasticity/CBviscoelasticity/CB Dispersion

95

1

2

Kuraray Liquid Rubber

�Category

Type

L-IR

Homopolymer(Isoprene)

Grade name

Number offunctionalgroups permolecule

Structure

L-IR-30

C CH
nL-IR-50

Block
Copolymer

L-IR-390

-

-

CH CH

C CH

n

m

Carboxylated
L-IR-403

C CH

C CH CHm
O

L-IR-410

UV Curable

UC-102M

C CH

C CH

(Butadiene)

O

10

2

C CH CHHCO C C O
HO O

mHomopolymer

O

C CH CHHCn
O C C O
HO O

m

UC-203M
L-BR

3

n

n

O
C

O

3

L-BR-302
L-BR-307

-

CH CH

n

L-BR-305
L-BR-352

-

CH

CH CH
m

CH

n

L-BR-361

OEt
EtO Si OEt

GS-L-BR(Graft silane)
GS-L-BR -114*

2
EtO Si OEt
OEt

L-SBR
(Styrene/

RandomCopolymer

L-SBR-870*
L-SBR-822*

Butadiene)

CH

CH

CH CH
m

l

CH

L-SBR-841N*
L-FR

n

L-FR-107L

RandomCopolymer

L-FBR-742

L-FBR-746*Developmental grades-

Homopolymer(Farnesene)

n

m

-

n

-

-

�

Molecular
WeightViscosity(Pa•s at 38°C)

Glass Transition
Temp. (°C)

28,00070-63

54,000500-6348,000400-95

34,000200-60Kuraray Liquid Rubber

Features and main applications▪ Reactive plasticizer (NR, IR, SBR, BR, IIR etc.)▪ Tire, conveyor belt, rubber goods▪ Pressure sensitive adhesives/hot melts▪ Automotive sealants, coatings and adhesives▪ Plasticizer for printing plates▪ Binder for brake pads, grinding wheels, etc.
▪ Hot melt adhesives/PSA (SIS, SBS, EVA)
▪ Automotive sealants, coatings and adhesives▪ Improves adhesion to metals and fibers▪ Automotive sealants, coatings and adhesives▪ Hot melt adhesives/PSA (SIS, SBS, EVA)
▪ Binder for brake pads, grinding wheels, etc.
30,000430-59

17,00030-60

35,000

190

-60

5,500

0.6

-85

8,000

1.5

-95

26,000

40

-95

9,000

6

-60

5,500

5.5

-49

6,000

6

-50

6,000

250

-18

8,800

8.3

-60

10,000100 (at 60˚C)-6130,000

70-70

30,00015-78

100,000

520-78▪ Low temperature reactivity▪ Crosslinkable using UV▪ Pressure sensitive adhesives (UV curing adhesives)▪ Reactive plasticizer (NR, IR, SBR, BR etc.)▪ Tire, printing plate▪ Coagent for EPDM (peroxide curing)▪ Automotive sealants, coatings and adhesives▪ Hot melt/PSA▪ Vinyl content: 5-70%▪ Thermoset PU modification▪ Tires, truck and bus tires and rubber goods▪ Improve silica-polymer interaction▪ Improve silica dispersion▪ Good compatibility with S-SBR and E-SBR▪ Tires, ultra-high-performance (UHP) tires and rubber goods▪ Automotive sealants, coatings and adhesives▪ Partially hydrogenated grades are available▪ Damping▪ Flexo printing plates▪ Tire, rubber goods, adhesives and sealants▪ Bio-based▪ Significant GHG reduction

3

4

Kuraray Liquid Rubber

�Liquid Farnesene Rubber
Sustainability and performance side-by-side
With liquid farnesene rubber, Kuraray is expanding its
portfolio of liquid rubbers with a product based on naturaland renewable raw materials.
As an additive in rubber compounds, liquid farnesene rubber
gives them high plasticity. The material also retains excellent
flexibility at low temperatures and improves ice grip while
preventing the rubber compounds from hardening over time,making it ideal for use in winter tires.

�

Kuraray Liquid Rubber

Applications*:
� Tires� Rubber goods
� Footwear� Adhesives, sealant and coatings

Benefits:� Renewable monomer� Low viscosity
� High reactivity

Renewable monomer
Low viscosity
High reactivity

Sugarcane
Branched Structure

Reactive site

: Double bond
β-Farnesene

Liquid farnesene rubber: Branched polymer

Less entanglement
between molecules
because of highly
branched structure*For certain applications, liquid
farnesene rubber cannot be
introduced due to raw material
supply relations. Please contact
our sales representatives.

High Mw
and Low
viscosity

5

6

Kuraray Liquid Rubber

�Curability of liquid rubbers changes
when curing agent is changed.
Sulfur cure2)
1,E+071,E+071,E+051,E+051,E+031,E+03

G’/Pa

G’/Pa

Crosslinked

Peroxide cure3)

1,E+01
1,E-01

Uncrosslinked
paste

Crosslinked

1,E+01
1,E-01*Not cured in this formulation*Not cured in this formulation

1,E-03

0

10

20

30

40

50

60

1,E-03

Time/min.

L-FR-107L

L-FR/L-FBR
show fastcrosslinking
with both sulfur
and PO.

0

10

20

30

40

50

Time/min.

L-FBR-746

2) Formulation
Liquid Rubber 100, ZnO 2, SA 1,
AO 1, S 3, DM 1.5, DT 0.5

1,2-L-BR

1,4-L-BR

3) Formulation
Liquid Rubber 100, PO 1

60

Uncrosslinked
paste

�

Kuraray Liquid Rubber

GHG emission index ofKuraray Liquid Rubber

Up to 108%
reduction ingreenhouse gas
emissions*

Principles & Frameworks
� ISO14040:2006 and ISO14044:2006
� Lifecycle Inventory database: IDEA (Inventory

Database for Environmental Analyses) version 2.3

Greenhouse gas emission index

100
80
60
40
20
0
-20

L-IR-50

L-BR-307

Kuraray Liquid Rubber

L-FR-107L L-FBR-746 L-FBR-742

Liquid Farnesene Rubber

� LCIA model: IPCC AR5 100a

System Boundaries
� Cradle to gate
� Biogenic carbon absorption is included� Incineration and transportation to customer sites

are not included

Assumptions and Limitations:
For detailed information on assumptions and limitations, please contact
our sales representatives.

7

8

Kuraray Liquid Rubber

�

Kuraray Liquid Rubber in tires
Three key parameters determine tire performance: grip, fuel efficiency
and durability. Kuraray Liquid Rubber offers advantages for tiregeometry, dynamic tire properties, heat generation and processability.
Kuraray Liquid Rubber functions as reactive plasticizers but have
far higher molecular weight than normal plasticizers, that reduces
bleeding and soiling of molds.

1

4

Beadfiller/APEX:� Improved dynamic and physical proterties (tanδ)� Excellent abrasion resistance, wet and ice grip
� Excellent extrudability
Applicable grades: L-IR-50, L-BR-302, L-BR-307,
L-SBR-870, L-SBR-841N, L-FR-107L, L-FBR-742,
L-FBR-746, GS-L-BR-114

Side wall / Carcass:5

� Improved dimensional stability
� Enhanced surface smoothness of calendered sheet
� Lower mill shrinkage
� Better green tackiness� Higher production rates
Applicable grades: L-IR-50, L-BR-302, L-BR-307

3

� Improves grip performance (ice, wet and dry)� Improves rolling resistance� Improves abrasion resistance� Low migration
� Improves filler dispersion

Tread:

� High hardness with excellent processability� Improved dimensional stability
� Better filler dispersion
� Improve green tack
Applicable grades: L-IR-50

2

Benefits:

Cushion:� Enhanced surface smoothness of calendered sheet
� Reduced extrusion temperature� Better green tackiness� Improvement of dynamic properties
Applicable grades: L-IR-50, L-BR-302, L-BR-307

Rim cushion:
� Good balance of processability and physicalproperties
� Improved abrasion resistance
Applicable grades: L-IR-50

4
5

1

3
2

�

Kuraray Liquid Rubber

9

Silane-modified GS-L-BR
Features

Silane coupling agents are used insilica-filled rubber compounds toincrease filler-polymer interactions
and lower the filler-filler interactions.

� Improves silica dispersion
� Crosslinkable with rubber base� High reactivity with silica
� Improves silica-polymer interaction
� Lower silica-silica interaction

In addition, silane functionalized low
molecular weight ‘liquid’ polymers canbe used. Our silane-modified GS-L-BR
is one of the latest development offunctionalized liquid rubber grades.

What is the function of GS-L-BR in rubber compounds?
Crosslink
Solid rubber

Expectation
� Good silica dispersion
� Improved abrasion resistance� Low tanδenhanced fuel economy

SilicaGS-L-BR
Vulcanization

Formulation & mixing conditions
Control

Formulation

Mixing Conditions

S-SBR

80

80

BR

20

20

0'00"

Solid rubber (60˚C)

TDAE

40

30

0'20"

Filler, SCA, Oil, LR, AO, ZnO, Stearic acid

Kuraray liquid rubber

-

10

5'30"

Dump out (150-160˚C)

Silica100

100

SCA (Si-75)

8.0

8.0

0'00"

First mixed compound (90˚C)

ZnO

3.0

3.0

4'30"

Dump out (150-160˚C)

Stearic Acid

2.5

2.5

NP1		

NP2		

FM		

Banbury-type mixer

Banbury-type mixer

Banbury-type mixer

Anti oxidant 6C

2.5

2.5

0'00"

Compound, S, Accelerator (50˚C)

Wax

2.0

2.0

0'75"

Dump out (90-100˚C)

OT-20

1.9

1.9

Accelerator DPG

0.5

0.5

Accelerator CBS

3.5

3.5

Accelerator TBTD

1.5

1.5

Structure & typical properties of GS-L-BR
Structure

Development code

Mw

Tg
(˚C)

Number of functionalgroup / chain

6,000

-50

2

5,500

-49

none

Graft functionalized
GS-L-BR-114*

L-BR

Non-functionalized*Only for the research purpose.

Summary
Feature of GS-L-BR-114
� Better rolling resistanceand silica dispersion
than L-BR
� Better abrasion
and wet grip
performance
Rolling
resistance@60˚C

GS-L-BR issuperior in termsof well-balanced
properties.

Abrasion
resistance120
GS-L-BR-114
100

TDAE (control)80

60

Silica dispersion

Wet
grip

10

Kuraray Liquid Rubber

�

Kuraray Liquid Rubber in automotive sealants
For automotive adhesives, grades of Kuraray Liquid Rubber, which are high-viscosity synthetic rubbers, offer different
functionalities: improving adhesion to metal surfaces while tailoring damping performance.
In addition, Kuraray Liquid Rubber improves adhesion to oily surfaces and is used where low-temperature performance andquick curing are required. With liquid farnesene rubber, Kuraray even offers a bio-based alternative for automotive sealants.

Benefits:

Applications:� Bio-based material
� High reactivity - curable with both sulfur and peroxide
� Good low temperature properties thanks to low Tg
� Provides damping properties over a wide temperature
range combined with high Tg liquid rubber
� Foams with fine cells

� Mastic sealant� Foam sealant� Anti-flutter

�

Kuraray Liquid Rubber

11

Automotive applications and benefits
GradeApplications

Benefits

L-IR-390▪ Sealants▪ Sprayable/foam-able sealants▪ Anti-flutter adhesives▪ Oil replacement▪ Cold temperature properties▪ Ip/Bd structure provides good crack resistance, better
damping performance, good compatibility with BR,hydrocarbon and rosin resins▪ Good solubility in aliphatic, aromatics and ethers▪ High reactivity due to Ip/Bd structure▪ Improves expansion in foams▪ Improves heat and abrasion resistanceL-IR-403
L-IR-410▪ Spot welding sealants▪ Anti-flutter adhesives▪ Flexibility improver for Multi-substratebonding▪ Good bonding to wide variety of substrates▪ Joining of dissimilar materials▪ Improved adhesion to oily surfaces▪ Softness▪ Higher Mw helps prevent sagging

L-IR-30
L-IR-50▪ Mastic sealants▪ Extrudable rubber-based patches▪ Oil replacement▪ Underbody coatings▪ Better processability and reactivity in mastic sealants(BR, SBR, IR)▪ No migration▪ Compatible with a broad range of vegetable oils
▪ Higher Mw helps prevent sagging

L-SBR▪ Sprayable/foam-able sealants▪ Spot welding sealants▪ High damping foams and acoustic baffles(LASD)▪ Excellent sound and vibration damping▪ High tanδ over a wide temperature range▪ Improves reactivity▪ Improves expansion in foams

Promote adhesion to metal: L-IR-403 & L-IR-410
L-IR-30

L-IR-403

Shear strength test

Al Plate

Steel Plate

Max load (N)82

77Elongation (mm)

1.8

0.9

Shear strength test

Al Plate

Steel Plate

Max load (N)

721

650

Elongation (mm)

4.4

4.1

Adhesion failure

Cohesion failure
Shear stress
Shear stress
Adhesion area: 25 mm x 25 mm

12 Kuraray Liquid Rubber

�

Kuraray Liquid Rubber in adhesives
Kuraray Liquid Rubber is commonly used in applications such as pressure sensitive adhesives and hot melts. The lower
molecular weight grades improve tack and adhesive properties. The UV crosslinkable grades provide excellent flexibility,
tack, low shrinkage and moisture resistance, which are ideal for flexible electronic applications.

Benefits:
� Preservation of rubber-like properties at low temperatures
� Colorless, transparent, odorless without halogen residuals
� Certain grades are suitable for food contact applications
� Improved adhesion to metal and glass possible with functionalized grades� Crosslinkable by UV with methacrylic grades�Solvent

Kuraray Liquid Rubber

L-IR-30, 50

L-IR-410

Hexane, Heptane,
Cyclohexane
Solubilityof L-IR

A

A

Toluene, Xylene

A

A

Methyl Acetate

CC

Ethyl AcetateCAn-Butyl Acetate

A

A

Acetone

C

C

MEK

C

A

MIPK

B

A

MIBK

A

A

Methanol, Ethanol

CC

Chloroform

A

A

Carbon TetrachlorideAA

A: Soluble

Carbon DisulfideAA

B: Partially soluble

Cyclohexanone/Xylene (50/50 wt/wt)

AA

Gel fraction (%)

UV Crosslinking system for UC-102M
100
90
80
70
60
50
40
30
20
10
0

UC-102M/NDDA=50/50
UC-102M/NDDA=75/25
UC-102M/NDDA=100/0
0

5

10

UV irradiation (pass)
Lamp: High pressure mercuray lamp
Curing conditions: Light intensity : 40 mW/cm2, Conveyor speed : 2 m/ min, 1 Pass = 188 mJ/cm2
Thickness: 0.8 mm
Gel fraction test: Toluene extraction at 25˚C for 24 hours

Polymer content: 20 wt% at 25˚C

C: Insoluble

13Adding value to your products–worldwide

Frankfurt,
Germany

Tokyo,
Japan

Houston,Texas, USA

Shanghai,
China
New Delhi,IndiaSão Paulo,
BrasilKuraray is a world leader in specialty chemicals andfunctional materials. We are committed to developing
products that ensure quality and value while helping
our customers differentiate themselves from theircompetition.
Kuraray's Elastomer Division started in 1972 withthe production of polyisoprene rubber and thedevelopment of new rubber materials based on
Isoprene in the Kashima Plant. From the first

production line, the Elastomer Division continuously
grew and invented new products such as KURARAYLIQUID RUBBER, ISOBAMTM, SEPTONTM,HYBRARTM, and KURARITYTM.
Kuraray strives to develop new and innovative highperformance products for customers around theglobe. Learn more about Kuraray's Elastomer
products, visit elastomer.kuraray.com.

Kuraray Co., Ltd.
Tokiwabashi Tower
2-6-4, Otemachi, Chiyoda-ku,
Tokyo 100-0004, Japan

Kuraray Europe GmbH
Philipp-Reis-Straße 465795 Hattersheim am Main
Germany

Kuraray America, Inc.
3700 Bay Area Blvd., Suite 680
Houston, Texas 77058
United States of America

P +81 3 6701 1616

P +49 69 305 85300

P 1.800.423.9762

� kuraray.liquidrubber@kuraray.com

� elastomer@kuraray.com

� septon.sales@kuraray.com

Kuraray Trading (Shanghai)Co., Ltd.
3 Hongqiao Road, Xuhui District
Shanghai 200030, China

Kuraray India Private Limited
Prius Platinum 2nd Floor B Wing,
D3 District Centre Saket
New Delhi -110017, India

Kuraray South America Ltda.
Av. Paulista, 1636 - Sala 405
01310-200 Sao Paulo, Brasil

P +86 21 6407 9182

P +91-11-4090-4400

� elastomer.china@kuraray.com

� inquiry.kid@kuraray.com

P +55-11-2615-3531
� elastomer.sa@kuraray.com© Kuraray Co., Ltd. 2023
SEPTON, HYBRAR, KURARITY and ISOBAM are trademarks or registered trademarks of Kuraray Co., Ltd. Trademarks may not be applied for or registered in all countries.
Disclaimer: The information provided herein corresponds to Kuraray’s knowledge on the subject at the date of its publication. This information may besubject to revision as new knowledge and experience becomes available. The information provided falls within the normal range of product properties andrelates only to the specific material designated; this data may not be valid for such material used in combination with any other materials or additives or inany process, unless expressly indicated otherwise. The data provided should not be used to establish specification limits or used alone as the basis of design;
they are not intended to substitute for any testing you may need to conduct to determine for yourself the suitability of a specific material for your particularpurposes. Final determination of suitability of any material or process and whether there is any infringement of patents is the sole responsibility of the user.
Since Kuraray cannot anticipate all variations in actual end-use conditions, Kuraray makes no warranties and assumes no liability in connection with any useof this information.

02/2023
For the latest information visit: elastomer.kuraray.com