ThreeBond Technical News
Issued July 1, 201382

Single-Component Low-Heat High-Speed
Curing Elastomeric Adhesive
Introduction
At ThreeBond, we have been offering single-component elastomeric adhesives that cure at room
temperature through our ThreeBond 1530 Series since 2000. Since its release, this series has beenutilized in a wide variety of applications.
In recent years, there has been growing demand for higher energy efficiency, cost reduction andshortened takt time at manufacturing sites, as well as product development that takes overall CO2
emission reduction and other environmental concerns into consideration. This kind of productdevelopment is beneficial to both production and to users.
We developed ThreeBond 1539 with these concerns in mind, utilizing plant-based materials tocreate a single-component elastomeric adhesive that cures quickly at low temperature, unlike otherconventional single-component adhesives.
Here, we will introduce both the development history and special features of this product.
Hereafter, ThreeBond is abbreviated as TB.

Table of Contents

Introduction.................................................1
1. Background.............................................2
1-1 Recent Environmental Issues..........2
1-2 Biomass Resources.........................2
2. Castor Oil................................................2
3. Elastomeric Adhesives............................3
4. Single-Component Low-Heat HighSpeed Curing Elastomeric Adhesive
TB1539....................................................3
4-1 Development Background...............3

4-2 Fluid Flow Characteristics when
Heat is Applied (Quick, Low
Temperature Curing)........................4
4-3 Characteristics/Curing Properties...4
5. Characteristics........................................5
5-1 Tensile Shear Bond Strength...........5
5-2 Viscoelasticity (DMA) ......................6
5-3 Heat Resistance ..............................6
5-4 Water-Resistance.............................6
6. Applications Examples...........................7
Closing........................................................81

1.

Background

1-1 Recent Environmental Issues
Reducing CO2 emissions that causes the greenhouse effecthas become a major concern as global warming issues
continue to take hold across the world. Industrial waste
disposal of plastic products has also continued to become agreater and greater issue with every passing year.
In light of these circumstances, “Carbon Neutral”
has become a buzzword in the environmental science
community, bringing focus on plant-based materials andother components that place very little burden on theenvironment. These materials neither increase nor decrease
atmospheric CO2 , even when incinerated, so products
made of such materials are regarded as environmentallyconscious.

1-2 Biomass Resources
Biomass is the general name for bioresources that comefrom animals and plants. Unlike finite fossil resources, suchas coal and petroleum, biomass resources are renewable aslong as there is sun, water and plant life. These resources
are being aggressively pursued as the above-mentioned
global warming issues face more and more scrutiny as the
21st century progresses. In recent years, research has been
underway to develop general-use petroleum-based polymers
from materials such as biomass ethanol. However, whilebiomass ethanol itself is carbon neutral, additional CO2 may
be released through its production and consumption (i.e.
energy when ethanol is produced from raw materials), so it
is necessary to consider whether production is appropriate
from the prospective of energy balance.
Against such a backdrop, ThreeBond has conducted productdevelopment focused on castor oil, a biomass resources thatis relatively easier to produce and obtain than petroleumbased polymers.

2.

Castor Oil

Castor oil is a non-edible oil made of pressed and refined
castor beans that has long been utilized as a lubricant,laxative, etc. Castor bean can be grown in relatively nutrientlight soil, so it is produced in many countries, from India andChina to Brazil. Additionally, there have been findings thatsuggest that castor bean plants absorb more CO2 than riceand other agricultural crops, making it an environmentallyfriendly resource.
Because ricinoleic acid is the main component of castor oil,it also boasts properties such as flexibility, low temperature
performance, stability, electrical properties and biologicalinactivity traits that make it extremely useful as a main
adhesive component (Fig. 1).

Castor bean flower

Castor bean plant

Castor bean seed

Pressed oil

Castor oil
O

O

OH

O

OH

O

OH

O
O

Fig. 1 Castor Oil and its Raw Materials (ricinus)

2

Table 1 ThreeBond Elastomeric Adhesive (Representative Grades)
Category

Silicone-based

Modified silicone-based

Acrylic-based

Product grade

TB1220 series

TB1530 series

TB3955Single component
moisture-curing

Single component
moisture-curing

Two-component
mixingCuring speed

△

△

○

Adhesive strength

△

○

◎

Flexibility

◎

◎

○

Heat resistance

◎

○

◎

Low molecular mass siloxane

△

None

None

◎: Excellent○: Good

Table 2 TB1530 Physical Characteristics(Representative Grades)
TB1530

TB1530B

Appearance

-

White

Black

Viscosity

Pa·s

100

110

100

3TS-2F00-002

Specific
gravity

-

1.39

1.31

1.31

3TS-2500-002

Tack-free
time

min

7

7

7

3TS-3130-006

Hardness

Durometer
A

44

48

55

3TS-2B00-004

Tensileshear bondstrength(A1/A1)

MPa

6.6

4.4

4.3

3TS-4100-013

Tensilestrength

MPa

5.9

3.0

4.1

3TS-4190-001

Elongation
rate

%

280

380

200

3TS-4190-001

3.

TB1530C

Testing
methodUnit

Semi3TS-2100-002
transparent

Elastomeric Adhesives

In recent years, silicone, modified silicone, polysulfide,
urethane and other elastomeric adhesives are increasingly
used because they easily bond to a wide range of adherends.
At ThreeBond, we have broadly classified three productgrades based upon main component (Table 1).
Base resins have different characteristics and properties, so
selection is based on the intended use. The TB1530 series
is mainly composed of modified silicone. It is a singlecomponent elastomeric adhesive that cures through moistureat room-temperature and features excellent adhesion to a△: Moderate

relatively wide range of materials, so it has been adopted bymany markets for a wide variety of applications (Table 2).
However, while the single-component moisture-curing
adhesives typified by the TB1530 series are easy to handle,
they also require around an entire week to cure at room
temperature. This necessitates a switch to two-component
types to speed up the curing process, making applicationof temperatures of 100°C or more required. This makes
handling at production sites difficult while also posing
danger to the environment.
To remedy these issues, we developed a single-component
elastomeric adhesive that quickly cures at low temperature
while maintaining excellent adhesiveness, shortening
takt time at manufacturing sites while also enabling useof elastomeric adhesives in applications where it had
previously been impossible due to manufacturing processes
and heat-resistance of materials. We are certain this range ofapplication will only further expand moving forward.

4.

Single-Component Low-Heat HighSpeed Curing Elastomeric Adhesive
TB15394-1 Development BackgroundAs mentioned above, single-component elastomericadhesive that cures at room temperature requires a long time
to cure, and because it cures through moisture in the air, it is
not suitable for large adherends, potting, etc. As a solution
to this, we set our sights on research and development ofan all-new single-component elastomeric adhesive thatwould cure quickly (from about 1 min.) at a relatively low
temperature of 60°C.

31.00E+06

8070

Initial reaction temperature
1.00E+05

50

Practical strength achieved

1.00E+04

40
1.00E+03

30
20
Temperature

100Viscosity (Pa·s)

Temperature ( °C)60

1.00E+02

Viscosity
0

30

60

90

120

150

180

1.00E+01

Time (sec.)

Fig. 4 TB1539 Fluid Flow Characteristics when Heat is Applied (Quick, Low-Temperature Curing)

Combining polymer modified castor oil mainly composedof plant-based components with a thermally latent curing
agent that activates at the relatively low temperature of
60°C enabled the development of the TB1539 elastomericadhesive, which has the following properties (Fig. 2 and 3).
Organotin compounds are widely used as a catalyst in
moisture-curing elastomeric adhesives, but such compounds
are not contained within TB1539, making it compliant with
EU directives applied from 2015.
TB1539 maintains a rubber-like elasticity after curing forbonding and sealing where impact, vibration and stressresistance are required. The adhesive bonds well to a wide
variety of adherends, from metal to plastic and glass, whichenables use in a broad range of fields, such as electronics
and transportation equipment, with expansion into many
more expected in the future.

4-2 Fluid Flow Characteristics when Heat isApplied (Quick, Low Temperature Curing)
Fig. 4 shows changes in viscosity as captured by a thermalrheometer when TB1539 is heated at a rate of 5°C/min.
After reaching the initial reaction temperature (about 60°C),
viscosity rises sharply then stabilizes after a short time
(under 1 min.), at which point practical strength is realized.
Fig. 4 is an example of curing behavior, so curing time mayvary depending on the heat capacity (heat transference
characteristics) of the adherend.

4

Fig. 2 TB1539 (Product Specifications)Fig. 3 TB1539 (Left: Pre-Cured, Right: Cured)

4-3 Characteristics/Curing Properties
TB1539 characteristics and curing properties are indicated inTable 3. The elastomeric adhesive demonstrates appropriate
viscosity to enable excellent workability and is rubbery.
4-3-1 Tensile Shear Bond Strength
TB1539 tensile shear bond strength is indicated by curing
time in Figure 5. High adhesive strength can be achieved
simply through 1.5 hours of 60°C heat. Strength is thenfurther improved through curing at 23°C, 50% RH.

Table 3 TB1539 Characteristics/Curing Properties
Testing method

Appearance

-

Black

3TS-2100-002

Viscosity

Pa·s

100

3TS-2F00-002

Specific gravity

-

1.34

3TS-2500-002

Hardness

Durometer A

70

3TS-2B00-004

Tensile strength

MPa

3.5

3TS-4190-001

Elongation rate%120

3TS-4190-001

Volume resistivity

Ω·m

2.4×1011

3TS-5200-001

8.0
7.0
6.0

4.0

100

3.0
2.0

Elongation rate

1.0

Tensile strength

0.0

0

5

10

15

Time (Days)

20

50

0
30

25

Fig. 6 TB1539 Tensile Strength by Curing Time

7.0

Hardening conditions: 60°C × 1.5 hrs
Curing conditions:
23°C, 50% RH
Testing method:
3TS-4190-001

6.0
5.0

100
90

4.0

20

25

30

Fig. 5 TB1539 Tensile Shear Bond Strength byCuring Time

20
10
0

Characteristics

5-1 Tensile Shear Bond Strength
TB1539 tensile shear bonding strength is indicated byadherend material in Figure 8. Excellent adhesion strengthis demonstrated for metal, various plastics and othermaterials.

10

15

20

25

30

Time (Days)

Fig. 7 TB1539 Hardness by Curing Time

Hardening conditions: 60°C × 1.5 hrs
Curing conditions:
23°C, 50% RH
Testing method:
3TS-2B00-004
Tensile Shear Bond Strength (MPa)

4-3-2 Tensile Strength, Elongation Rate andHardness
TB1539 tensile strength, elongation rate and hardness areindicated by curing time in Figures 6 and 7. In the same
way as for tensile shear strength, rubber-like characteristics
are obtained simply by applying 60°C heat for 1.5 hours.
Properties then stabilize by curing in 23°C, 50% RH.

50Hardening conditions: 60°C × 1.5 hrs
Curing conditions:
23°C, 50%
Testing method:
3TS-4100-013, bonded aluminummaterials (A1050P) together after
applying to adherends

5
4
3
2
1
0

Glass

15

Time (Days)

Epoxy glass

10

Phenol resin

5

40
30

PBT

0

50

PET

0.0

60

Copper

1.0

70

Iron

2.0

80

Aluminum

3.0

Hardness (Durometer A)

RH Tensile Shear Bond Strength (MPa)

150

5.0

Curing conditions: 60°C × 1.5 hrs + 23°C, 50% RH × 3 days

5.

200

Elongation rate (%)

TB1539Tensile strength (MPa)UnitFig. 8 TB1539 Tensile Shear Bond Strength byMaterial

Curing conditions: 60°C × 1.5 hrs + 23°C, 50% RH × 3 days

5

3TS-4100-013, bonded together after
applying to adherends

5-2 Viscoelasticity (DMA)
Measurements of TB1539 dynamic viscoelasticity when
cured are indicated in Figure 9. TB1539 maintains a rubberlike elasticity in a wide temperature range (-35 to 100°C).
1.0E+11

70
60
50
40
30
20
80˚C

100˚C

4

5

80˚C

100˚C

4

5

10

Glass range (1.0E+8 or more)
1.0E+900

1.0E+81

2

Rubber (Elastomer) range (1.0E+6 to 8)

3

Time (Weeks)6

1.0E+770

1.0E+660

Gel range (1.0E+6 or less)
1.0E+5-50.0 -40.0

-20.0

0.0

20.0

40.0

60.0

Temperature (°C)

80.0

100

120

Fig. 9 TB1539 Viscoelasticity
Curing conditions: 60°C × 1.5 hrs + 23°C, 50% RH × 3 days
Testing method:
3TS-4730-001

Tensile strength (MPa)Storage modulus (E’) Pa

1.0E+1080

Strength (Durometer A)

Testing method:

50
40
30
20
10

5-3 Heat Resistance
Cured TB1539 characteristics after exposure to 80 and
100°C environments are indicated in Figure 10.

00After six weeks of exposure in each temperature,
characteristics equal to that of their initial levels weremaintained and sufficient rubber characteristics were
demonstrated.

1

2

3

Time (Weeks)

6

180
160

5-4 Water-Resistance
Cured TB1539 characteristics after immersion in 40°C
water are indicated in Figure 11.
Water resistance and sufficient rubber characteristics were
demonstrated after six weeks of immersion, just as in heat
resistance.

Elongation rate (%)

140
120
100
80
60
40
80˚C

20

100˚C

0
0

1

2

3

Time (Weeks)

4

5

6

Fig. 10 Cured TB1539 Characteristics After
Exposure to 80 and 100°C Environments
Curing conditions: 60°C × 1.5 hrs + 23°C, 50% RH × 3 days

6

6.

Hardness (Durometer A)

80
70• Affixing and bonding automotive parts

60• Bonding and sealing electrical, electronic and medical
equipment parts, etc.

50

• Bonding and sealing various household products

40• Bonding various metals, plastics, rubber, etc.

30
20
40˚C water resistance test
10
0
0

1

2

3

Time (Weeks)

4

5

6

70

Moisture-curing elastomeric adhesive cures by coming
into contact with air, making it unsuitable for curing in
the center or deep sections of an object, such as for large
adherends or potting. Because TB1539 cures quickly at
low heats, these issues are eliminated, and it is suitable forbonding and sealing of bonded parts and other applications.
It also demonstrates excellent water resistance and electricalinsulation, making it perfectly suitable for electronics andother applications where such characteristics are required.
While other adhesives are difficult to use with plastics
due to softening that can occur during the heat curing
process, TB1539 cures at the relatively low temperature of
60°C while also demonstrating excellent bonding to such
adherents, making it excellent when used with a variety ofsuch materials. It is traits like these that make us confident
that TB1539 application will only continue to grow.

60

Tensile strength (MPa)Applications Examples

50
40
30
20
40˚C water resistance test
10
0
0

1

2

3

Time (Weeks)

4

5

6

180
160

Elongation rate (%)

140
120
100
80
60
40
40˚C water resistance test

20
0
0

1

2

3

Time (Weeks)

4

5

6

Fig. 11 Cured TB1539 Characteristics After
Immersion in 40°C Water
Curing conditions: 60°C × 1.5 hrs + 23°C, 50% RH × 3 days

7

Closing

TB1539 was developed for the purpose of creating an all new, environmentally friendly single-component elastomeric adhesivethat cures quickly at low temperatures.
Utilizing TB1539 is sure to realize improved energy efficiency at manufacturing sites, which will also reduce costs. This
adhesive is perfect for a wide range of applications in a variety of markets thanks to the many materials to which it can bebonded as well as excellent heat and water resistance. We will continue to expand this lineup, using TB1539 as the center ofthis new series.
As market demand continues to grow for environmentally friendly products, we at ThreeBond promise to also make this kindof development a priority, not only for the sake of the elastomeric adhesive field, but in the hopes of contributing to industrywide product development.
This content was published in the March, 2013 issue of Kogyo Zairyo (Engineering Materials) by NIKKAN KOGYO SHIMBUN.
ThreeBond Co., Ltd. R&D Headquarters
Kentaro Watanabe, Development Division, Working Materials Department
Manabu Kirino, Special Project Manager

ThreeBond Co., Ltd.
8

4-3-3 Minamiosawa, Hachioji,
Tokyo 192-0398
Tel: +81-42-670-5333