ThreeBond Technical News
Issued January 1, 2007

68

New Instant Adhesives
Introduction ________________________________________________
Initially tackled by Goodrich Corporation, USA, its efforts to develop instant adhesives date back to
1949. Eastman Chemical Company, a subsequent developer, achieved an instant adhesive suitable for
actual use. The development of instant adhesives was triggered by an accidental discovery by anengineer while testing a new product. As the engineer was attempting to measure the refractive index
of a newly synthesized cyanoacrylate, this organic compound became firmly attached to the prism of
the refraction meter. Thereafter, researchers focused attention on cyanoacrylate's adhesive properties.
In 1959, the first viable product was marketed under the name “Eastman 910.” Since that time, many
companies around the world have sought to modify and commercialize instant adhesives.
Our own efforts to develop instant adhesives began in 1969. Currently in the ThreeBond 1700 Series,
we release a product lineup offering various characteristics.
Just like it sounds, instant adhesives are adhesive agents that bind adherends rapidly – within several
to several tens of seconds. Due to their quick curing, versatility, and convenience, they have been used
in a wide range of applications ranging from domestic to industrial. In recent years, issues such as
global warming, fossil fuel resource depletion, and enhancement of working area are highlighted andcompanies have shifted their production lines to a streamlined architecture without furnaces to achieve
higher energy efficiency. This trend has led to the re-evaluation of the one-part solvent-free instantadhesives that offer instant and powerful bonding strength, and demand for such products is risingsteadily year after year worldwide.
This issue will introduce two products developed as a result of extensive and continuous research atour company to meet the demand for products with simpler workability.

Contents
Introduction .......................................................1
1 Advantages and Disadvantages of InstantAdhesives.....................................................2
2 Ultra-Fast Curing Instant Adhesive- ThreeBond 7700 Gold Label Series ...........2
2-1 ThreeBond 7700 Gold Label Series .....2
2-2 Characteristics of the ThreeBond 7700
Gold Label Series .................................2
2-3 Applications for the ThreeBond 7700
Gold Label Series .................................4

3 High Humidity-Resistant Instant Adhesive– The ThreeBond 1757 ................................ 5
3-1 ThreeBond 1757 .................................. 5
3-2 ThreeBond 1757 Characteristics.......... 5
3-3 Applications for ThreeBond 1757 ......... 7
Conclusion........................................................ 81

1

Advantages and Disadvantages ofInstant Adhesives

The primary component of instant adhesives are
2-cyanoacrylate esters, whose molecules featurepolarized electron distributions, with some areas
having high and other parts low electron densities,
due to the presence of strong electrophilic groups
such as the cyano group and carbonyl group. Instantadhesives can easily mount nucleophilic attacks,even on weak bases such as water (humidity), topromote anion polymerization.
This anion polymerization is extremely sensitiveand progresses rapidly in a linear fashion,
producing excellent fast-curing properties. But thelinear structure of the polymer chain also results inless desirable features, such as low heat resistance.
Table 1 lists the properties of instant adhesives.
Table 1.

Advantages and disadvantages of
instant adhesives

Advantages

Disadvantages

1

Quick curing at room
temperature

1

Low water andhumidity resistance2

One-part, solvent-free
agent

2

Blooming

3

High bonding strength3

Low heat resistance(80°C)

4

Capable of bonding a
4wide range of materials

5

Capable of bonding
materials of different
types

5

Rigid cured product6

Low materials use

6

Unsuitable for high-gap
filling adhesion

Low impact resistance

Although the fast-curing property of instantadhesives is most recognized, their capacity to bind
together nearly any material is another noteworthy
advantage. The instant adhesives are used in various
purposes, from domestic, industrial, to medical
applications.
On the other hand, instant adhesives have certain
disadvantages listed in Table 1. They generally offer
poor water and humidity resistance, making them
unsuitable for use under wet or humid conditions.
Blooming also makes them less useful for
applications that must require good appearance.
Aslo, since the cured products with instantadhesives are hard and brittle, they offer less impact
resistance, peeling resistance, or thermal cycle
resistance.
The selection of appropriate monomers and thestudy of additives are gradually eliminating thesedisadvantages. Blooming may be avoided by using
cyanoacrylate ester at low vapor pressure(ThreeBond 1720D series) or by using instant2

adhesives to which light-curing properties havebeen added (ThreeBond 1770E Series). Thispermits instant curing of any projecting parts using
ultraviolet or visible light. These light-curing instantadhesives also enable high-gap filling adhesion
through a combination of humidity curing and lightcuring processes. Alloying with the addition ofrubber components to the adhesive agent improves
impact resistance, peeling resistance, and thermal
cycle resistance.

2

Ultra-Fast Curing Instant Adhesive ThreeBond 7700 Gold Label Series

2-1 ThreeBond 7700 Gold Label Series
By now, the rapid curing of instant adhesives iscommon knowledge and is the key feature that canbe imagined when he/she hears the term. But formaterials that are difficult to bond, such as porousor acidic materials like paper or wood, EPDM, andpolyacetal, the rapid bonding expected bycustomers cannot be achieved. In addition,
environmental issues and energy efficiency
concerns have led to demands for highly efficient
production lines in factories. One strategy toachieve this goal is the design of high-speed
production lines. One-part instant adhesives thatcure quickly at room temperature improve
workability and are well-suited to such applications.
Thus, the development of products with suchproperties may contribute to environmental
conservation.
In response to such trends, we have decided toreturn to the starting line with respect to instantadhesives and to promote the development of
products that commit to “bond in a fraction of asecond.” We have focused our efforts on improving
the purity and quality at the monomer level to create
instant-binding adhesives, successfully developing
the potent, ultra-fast curing adhesives as theThreeBond 7700 Gold Label Series.
2-2

Characteristics of the ThreeBond 7700
Gold Label Series
Table 2 lists the properties and characteristics of
the ThreeBond 7700 Series (“ThreeBond” will bereferred to as “TB” hereinafter).
Figure 1 illustrates the set time for TB7781 as arepresentative example; Table 3 lists the bonding
strengths to various adherends.

Table 2. Properties and characteristics of the TB7700 Series

Advantages

Unit

Ultra-Fast Curing Series

TB7741

TB7781

TB7782

TB7784

Test Method-

Clear, pale yellow

Clear, pale yellow

Clear, pale yellow

Clear, pale yellow

3TS-201-01

ViscositymPa • S

2

2

15

160

3TS-210-01

Specific gravity

-

1.05

1.05

1.05

1.06

3TS-213-02/°C

81 - 124

79 - 116

77 - 121

83 - 135

3TS-501-05

°C

110

107

109

118

3TS-501-04

-

D80

D80

D82

D82

3TS-215-01

kV/mm

30

30

27

26

3TS-406-01

Volume resistivityΩ•m

1.5 × 1014

1.6 × 1014

1.8 × 1014

1.5 × 1014

3TS-401-01

Surface resistivityΩ

1.2 × 1015

6.2 × 1014

1.0 × 1015

1.8 × 1015

3TS-402-01

Properties

Appearance

Coefficient of linear
expansion (0-100°C)
Glass transition point(DMA E’’)
Hardness
Dielectric breakdown
voltage

Dielectric

1MHz

-

3.51

3.93

3.85

6.08

constant

1kHz

-

3.05

3.42

3.33

5.29

Dissipation

1MHz

-

0.037

0.037

0.038

0.037

factor

1kHz

-

0.028

0.028

0.029

0.028

3TS-405-01

Conventional fast-curing adhesives

Set time (sec.)

Characteristics

Standard

Iron

Japanese Beech
cypress

Acid
paper

Figure 1. Time required for TB7781 to set on various adherends (3TS-220-04)

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Table 3.

Bonding strength of TB7781 tovarious adherends
Adherend typeTensile lap
shear strength
(MPa)

Iron

14.0

Aluminum

14.9

SUS

12.2

Brass

9.0

Copper

12.7

Nickel13.3

Zinc chromate

7.5

Hard vinyl chloride

3.0

PC (Polycarbonate)

6.9*

Phenol10.5*6-Nylon

8.1*

6,6-Nylon

13.1*

Noryl

9.3*

ABS (Acrylonitrile-butadiene-styrene
resin)

6.2*

Glass epoxy

19.2

PBT (Polybutylene terephthalate)

4.3

PET (Polyethylene terephthalate)

10.5*

PPO (Polyphenylene oxide)

8.0

PPS (Polyphenylene sulfide)

1.9

HIPS (High impact polystyrene)

4.4*

Acrylic

7.6*

Polyacetal

1.2

NR (Natural rubber)

0.4*

CR (Chloroprene rubber)

0.6*

NBR (Acrylonitrile butadiene rubber)

0.8*

SBR (Styrene-butadiene rubber)

1.7*

EPDM (Ethylene propylene
dieneterpolymer)

0.8*

Acid paper-*

Balsa wood

1.8*

Lauan wood (single panel)

8.8*Japanese cypress

11.2*(polyacetal) and acidic and porous materials such as
wood and paper. This is due to the high monomer
purity of TB7781, which is caused by less cureinhibition and faster polymerization. Since theadhesive cures before it seeps into the pores, theproduct provides excellent adhesive properties,
even with materials like wood. As shown in Table 3,
except for materials with strengths higher than theadhesive, such as metals, all adherends indicate
material failure (the failure of the adherend material
itself instead of the bonding area, which indicatesstrong adhesion), which suggests that the adhesive
will exhibit adequate bonding strength with a wide
range of materials.
2-3Applications for the ThreeBond 7700
Gold Label Series
TB7700Gold
Label
Seriesprovidesunprecedented ultra-fast curing properties notavailable in conventional products and they are
expected to contribute to increasing the efficiencyof various production lines. Their high curing speed
will not only speed up the line, but may help reduce
fixing jigs and the curing space required.
Their adoption will help realize the reduction inboth the energy consumed upon production and thetotal cost required for operation of the line. Some
major examples of their application are as follows:(1) General parts that require rapid adhesion(2) Adhesion of porous materials(3) Temporary fixation for epoxy resin or acrylic
resin adhesives that require time or fixation jigs
for curing* indicates material failure.

As shown in Table 2, we currently market one
standard product and three ultra-fast curing
products, which have different viscosities. All
products offer excellent curing properties andrelatively good shelf lives through thoroughremoval of impurities.
Figure 1 illustrates the comparison between set
times of our ultra-fast curing product andconventional product. Except for materials such as
NBR for which short set times had been achievedby conventional products, TB7781 (ultra-fast curingtype) clearly succeeds in reducing the set time fornearly all adherends, with significant reductions
seen in difficult-to-bond materials such as POM

4Photo 1. Appearance of the TB7700 series(Semi-transparent containers with light-blocking effect, thatthe remaining amount can be checked)

3High Humidity-Resistant InstantAdhesive – The ThreeBond 1757

3-1 ThreeBond 1757
As shown in Table 1, instant adhesives also haveseveral disadvantages, including poor water andhumidity resistance. To date, few methods havebeen reported to improve these characteristics. In
practice, there are few instant adhesive productsthat offer excellent resistance to high temperaturesand high humidity conditions or in water immersion.
Instant adhesives also provide low heat resistance(up to 80°C), which makes them unsuitable forapplications requiring durability. Due to thesedrawbacks, their instant bonding capacity andsuperior workability have not been fully
demonstrated. However, through dedicated effort
and investigations of methods for improving waterand humidity resistance, we have successfully
developed a high humidity-resistant instantadhesive that has a higher reliability by blending acertain reactive monomer. The following section
discusses this development in detail.

3-2 ThreeBond 1757 Characteristics
Table 4 lists the properties and characteristics ofTB1757. As with conventional instant adhesives,
TB1757 provides excellent adhesive performancefor various substrates.
Figures 2 and 3 show the humidity resistance ofTB1757. Figure 2 presents the results of tensile lap
shear strength measurements (tension test specimen
speed: 10 mm/min) conducted on aluminum platesbonded at 25°C, 50% RH, and cured for 72 hours
under the same condition, which were thenimmersed in an 80°C, 95% RH thermo-hygrostat
bath for the specified duration before measuring atroom temperature.
Figure 3 shows the results of peeling resistancemeasurements of a bond between iron with acationic electrodeposition coating and SEBS
(styrene- (ethylene-butylene) -styrene block
copolymer) formed at 25°C, 50% RH, and cured for
72 hours under the same conditions. The assembly
was then immersed in an 80°C, 95% RH
thermo-hygrostat bath for the specified duration
before measuring the 90° peeling resistance (tension
speed of test specimen: 50 mm/min) at room
temperature. The “TB1757/TB1797E” in the graphindicates that a primer (TB1797E: primer dedicatedfor the TB1750 Series) was applied to the SEBS
surface before adhesion.

Table 4. TB1757 properties and characteristics

Monomer

Items

Unit

TB1757

Test method
3TS-201-01

Appearance-

Clear, pale yellow liquid

Main component-

2-cyanoacrylate ester―

ViscositymPa • s1200

3TS-210-01

NBR

Set time

Iron

sec

19.2

Aluminum

16.0

ABS
PC

MPa

NBR

3TS-220-04

30

Iron

Tensile lap shear strength

8.1*

3TS-301-11

5.1*
0.8*

EPDM
Copolymer

20

0.8*

Coefficient of linear expansion (0-100°C)

10 /°C-6

90 - 140

3TS-501-05

Glass transition point temperature Tg

°C

122

3TS-501-04

Dielectric breakdown voltage

kV/mm

24.0

3TS-406-01
13

3TS-401-01

14

3TS-402-01

Volume resistivityΩ•m

15 × 10

Surface resistivityΩ

1.5 × 10

1MHz

-

2.87

Dielectric constantDissipation factor

1kHz

-

3.37

1MHz

-

0.029

1kHz

-

0.047

3TS-405-01* indicates material failure. See Table 3 for definitions of acronyms used in the table.

5Tensile lap shear strength (MPa)

Our conventional productExposure time (h)suppresses degradation. Bonding under dry
conditions produces excellent humidity and heat
resistance, with no observed reductions in bonding
strength, even under conditions of 80°C, 95% RH.
Figure 4 shows the water resistance of TB1757.
Tensile lap shear strength measurements (tension
speed of test specimen: 10 mm/min) were
performed on aluminum plates bonded at 25°C,
50% RH and cured for 72 hours under the same
condition. These were then immersed in water at
different temperatures for specified duration anddried for 24 hours at room temperature before
measurement.

Figure 2. Humidity resistance at 80°C, 95%
RH (for aluminum/aluminum bond)
TB1757 only

*

*

*

*

Exposure time (h)Figure 3. Humidity resistance at 80°C, 95%
RH (for the cationic electrodepositediron/SEBS bond)
The asterisks (*) in the graph indicate observed material
failure.

Figure 2 shows that the bonding strength ofcommon instant adhesive (our conventional
product) drops rapidly over time, with near-total
loss of bonding strength after 200 hours. In contrast,
the TB1757, although indicating a certain decline inbonding strength, continues to maintain bonding
strength exceeding 10 Mpa, even after aging of(80°C, 95% RH) x 1,000 hours.
Figure 3 also shows that TB1757 has excellent
humidity and heat resistance, even when bonding
between heterogeneous adherends such as cationicelectrodeposited iron and SEBS. Rubber elastomers
such as SEBS contain various additives and are
known to bloom or bleed under high humidity andheat conditions, and then tend to reduce bonding
strength due to degradation of the bonding surface.
However, the extent of degradation is markedly
lower with TB1757 than with conventional products.
Pre-treating the SEBS surface with TB1797E, aprimer dedicated for the TB1750 Series, further

6

Tensile lap shear strength (MPa)90° peeling resistance (N/15 mm)

Our conventional product at 80°C

Exposure time (h)Figure 4. Water Resistance
Figure 4 shows that while common adhesive (ourconventional product) lose nearly all bonding
strength after 100 hours of immersion in water at
80°C, the TB1757 retains a bonding strength above
8 MPa even after 1,000 hours.
Results from Figures 2, 3, and 4 show that the
TB1757 demonstrates sufficient resistance to wet
conditions under which conventional products fail.
Finally, Figure 5 shows the heat resistance ofTB1757. Iron plates were bonded at the respective
temperatures and tests of tensile lap shear strength
were performed at the same temperature. Figure 6
shows the results of tensile lap shear strength
measured at 120°C of specimens aged for the
specified duration at 120°C. Figure 7 shows theresults of tensile lap shear strength measurements
for iron plates after they were bonded, exposed toheat cycles alternating between -40°C x 1 hour and
120°C x 1 hour for the specified number of cycles,
and cooled back to room temperature.

Tensile lap shear strength (MPa)

Our conventional productTemperature (°C)

Tensile lap shear strength (MPa)Figure 5. Heat resistance (bonding strength
upon initial heating)Our conventional product

Aging time (h)Tensile lap shear strength (MPa)Figure 6. Heat resistance (bonding strength at
120°C after aging at 120°C)

Our conventional product

Number of cycles

Figure 7. Thermal cycle resistance

Figures 5 and 6 indicate that TB1757 maintains
excellent bonding performance even under hightemperatures. In particular, TB1757 retains its
initial bonding strength even after exposure to aging
of 120°C x 1,000 hours and measurement underheated conditions. No conventional product to datehas offered such exceptional and stable bonding
performance.
Figure 7 shows that TB1757 also provides
excellent thermal cycle resistance. Conventional
instant adhesives generally provides poor thermal
cycle resistance due to their hardness and brittlenessafter curing. In contrast, TB1757 maintains bonding
strength exceeding 10 MPa after 100 cycles, atestament to its capacity to withstand rapid
temperature changes.
Based on the above, we may conclude that water,
humidity, heat, and thermal cycle resistance, widely
considered poor with conventional instant adhesives
as shown in Table 1, have been greatly improved in
TB1757.
3-3 Applications for ThreeBond 1757
TB1757 applications cover a wide range of fields
including wet and other conditions to require highreliability, which conventional instant adhesives
could not support. Since TB1757 has not just highdurability but ultra-fast curing properties, we expect
it to help improve productivity on high-speed
production lines. This indicates that TB1757 canreplace epoxy resins and acrylic resins previously
selected for their reliability despite the fact that theyrequire furnaces or irradiation units, making it
possible to significantly streamline production lines
through a simple instant adhesive that cures at room
temperatures and humidity.
Some major applications are as follows:(1) Adhesion of parts for automobiles, air carriers,
electric, electronic, and general applications thatdemand high water, humidity, and heat
resistance(2) Adhesion of weather-stripping in windows ofautomobiles, etc.
(3) Adhesion of rubber and elastomer parts inrubber gaskets, etc, which require high waterand humidity resistance(4) Adhesion of motor magnet parts(5) Adhesion of parts for electronic installation

7

Conclusion
Over half a century has passed since instant adhesives entered practical use. During this time, numerous
companies have marketed a wide range of products, with fast-curing one-part adhesives that adhere to a wide
range of adherends, ensuring to use them in various applications and purposes. But instant adhesives also havedisadvantages, including poor water and heat resistance, which have discouraged their adoption for applications
requiring high reliability. We have undertaken the challenge of pursuing ultra-fast curing properties and deliveringhigh reliability in the applications of instant adhesives to fully leverage their advantages. We believe that the two
products introduced in this issue will help simplify the design for and enhance the efficiency of factory productionlines. Such designs are expected to reduce the energy consumed upon production, as well as the total cost of
production, while contributing to environmental conservation.
In closing, we appreciate your continued support as we strive to meet the needs of customers while pursuingefforts to develop new applications and open up new markets.
Yasuo Maeda
Hideki Takahashi
Masakazu Motoki
Industrial Materials Development Division
Development Department
Research Center
ThreeBond Co., Ltd.

1456 Hazama-cho, Hachioji-shi, Tokyo 193-8533, Japan
Tel: 81-426-61-1333

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