|
O-tolidine Diisocyanate
(TODI)
Urethane elastomer have various advantages when compared with rubber,
plastic and metal. This is especially true of the urethane elastomers
made using Tolidine diisocyanate (TODI). TODI-based elaastomers
offer excellent heat resistance and hydrolysis resistance properties
along with superior mechanical properties.
From the manufacturing stand point, TODI based prepolymer can be
stored for certain period, and TODI, because of its longer pot life,
is easlier to handle than NDI-based products.
Application of TODI urethane elastomer
Because of its unique properties of heat resistance and hydrolysis
resistence, TODI urethane elastomers can be used in various areas
including:
1) Sealing (oil sealing, piston ring, water sealed, etc.)
2) Automobile parts (grille, shock absorbers, bumoer extensions,
roof, door, window
and body, etc.)
3) Industrial use (belt, roll, caster, etc.)
4) Electric (coating agent, etc.)
5) Medical equipment (artificial organ, etc.)
What is TODI ?
| Name |
T.O.D.I., R203 (CAS No. 91-97-4)
4.4'-Diisocyanato-3.3'-dimethyl-1.1'-biphenyl
or 3.3'-Dimethyl-4.4'-biphenyldiisocyanate
or O-Tolidine diisocyanate |
| Chemical Structure |
 |
| Purity |
Min. 99.5 % |
| Molecular weight |
264.286 |
| Package |
40 kg Fiber drum with inner plastic bag |
| Storage
|
Keep cool and dry place |
|
Technical Information |
|
Physical and Chemical Properties
|
| 1. Appearance |
White pellets |
| 2. Odor |
Odorless |
| 3. Boiling Point |
195-197°C (5mmHg, or
667 Pa) |
| 4. Melting Point |
71.7°C |
| 5. Specific Gravity |
1.197 (80°C) |
| 6. Solubility |
Insoluble in water and
slowly hydrolyzed by water. Soluble in aceton, carbon
tetrachroride, kerosene, benzene, chlorobenzene, nitrobenzene |
| 7. Flash point |
218°C (cleveland open
cup) |
|
Procedure of Making TODI urethane elastomer
There are various combinations of materials, blending ratios and
manufacturing methods for achieving appropriate properties in TODI
based urethane elastomer. The following is just one example of making
a TODI urethane elastomer using the pre polymer method.
| 1) Materials |
|
| |
Isocyanate |
TODI |
| |
Polyester |
Ethylene glycol
Or Condensation product of Adipic acid and blended glycol,
Or Ring-opening polymerization polyester of Caprolactone
(M.W.; around 2,000, OH Value; about 56, AV<1 Acid Value) |
| |
Cross-Linking
agent |
1.4 Butanediol |
| |
Catalyst |
Triethlenediamine (DABCD, Houdry Process Corp.)
Stannous Octoate (T-9, T&M) |
2) Blending Ratio
Various blending ratios are used for obtaining the special properties
of urethane elastomer But, generally, desirable properties are
obtained within the following blending ratios:
NCO/OH (R*1)
= Between 2 and 4
NCO/OH (NCO
Index*2) = Between 1.1 and 1.4
*1; Molar ratio of -NCO from TODI and -OH from polyester in the
prepolymer
*2; Molar ratio of -NCO in prepolymer and -OH from cross linking
agent
|
Example 1. ODX-105(OH Value = 54.5)
|
| R |
NCO Index |
Polyester |
TODI
|
1.4 Butanediol |
| 2.0 |
1.1 |
100 |
25.7 |
3.6 |
| 2.6 |
1.2 |
100 |
33.3 |
5.1 |
| 3.0 |
1.1 |
100 |
38.5 |
7.6 |
|
|
Example 2. Caprolactone (OH Value
= 55.1)
|
| R |
NCO Index |
Polyester |
TODI
|
1.4 Butanediol |
| 2.0 |
1.2 |
100 |
25.9 |
2.9 |
| 2.6 |
1.2 |
100 |
33.7 |
5.2 |
| 3.8 |
1.1 |
100 |
49.3 |
10.9 |
|
3) Manufacturing Process (Pre-Polymer Method)
Making pre-polymer
Dehydrated polymer under reduced pressure (110-112°C, 1-2 mmHg,
for 2 hours) is poured in separable flask with stirrer and desiccators
and place in the oil bath held at 100°C. After the temperature of
polyester reaching 100°C, TODI is added into this flask. Although
the reaction of TODI and polyester is exothermic reaction, the increment
of temperature stops within a few minutes. So, cooling in not needed.
The addition reaction of TODI is finished when -OH of polyester
is consumed by the same molar amount of -NCO. (Reaction time for
ODX-105 is 2 hours, and for caprolactone is 2.5-3 hours at 100°C,
Fig.1). Viacosity change during this addition reaction is shown
at Figure 2.
|
Fig. 1. Relationship between reaction % and time in pre-polymer.
|
 |
| M-103ES = Caprolactone
polyester, ODX-105 = Condensation product of blended glycol
and adipic acid. R = -NCO/OH, Temperature of reaction
is 100°C |
|
Fig. 2. Relationship between reaction
% and Viscosity of pre-polymer.
|
 |
| M-103ES
= Caprolactibe polyester, R = -NCO/OH, Temperature of
reaction is 100°C |
|
Addition of cross linking agent (1.4 Butanediol)
and catalysis
200 g of pre-polymer is taken into 1 liter beaker, and heat to 110°C
on the electric heater. Dehydrated 1.4 Butanediol under the reduced
pressure is added into heated pre-polymer and stirred well. Temperature
of pre-polymer should not be over 115°C. Addition of 1.4 Butanediol
before the complete reaction of TODI and polyester does not change
the final physical properties of TODI urethane elastomer. The time
from the addition of 1.4 Butanediol until gelation (Pot Life) is depends
on the blended ratio. But addition of catalysis can shorten the Pot
Life and 2nd aging period. The physical properties of final product
are not changed. Generally DABCO Triethylendiamine) and T-9 (Stannous
octoate) are used as a catalyst for this reaction.
| Table
1 |
|
Effect of Catalysis amount on the physical
properties of TODI based urethane elastomer
|
Polyester
R
NCO Index
Reaction time of
Pre-polymer |
Caprolactone
3.8
1.1
1.0 |
Catalysis
Pot Life (seconds) |
0
270 |
0.3
100 |
0.5
60 |
| 1st aging (Hours) |
48 |
48 |
48 |
48 |
| 2nd aging (Days) |
10 |
50 |
10 |
10 |
| Tensile strength (Kg/cm2) |
273 |
360 |
363 |
379 |
| Tearing strength (Kg/cm2) |
117 |
139 |
142 |
143 |
| 100% Modulus (Kg/cm2) |
112 |
114 |
111 |
114 |
| Elongation (%) |
600 |
580 |
600 |
620 |
| Hardness (Shore A) |
95 |
95 |
95 |
95 |
|
De-gassing (Reduce pressure to 1-2
mmHg, within pot life)
Immediately after the1.4 Butanediol is added and stirred, the beaker
is placed in a desiccator and is de-gassing under the reduced pressure
(1-2 mmHg).
Molding
Generally metal molds (separate type) is used for molding. Each piece
of mold can be fixed with screw, and 3 mm spacer can be inserted between
each piece of mold. Each mold is coated by Silicone DC-20 (Dow Corning)
or Silicone KS-61, and heated around 110°C. Material is gently poured
into both molds without making any foam, and attached together and
fixed with a screw.
Detaching the Mold
The mold is placed in the oven and held at 110°C for 1-2 hours. The
time for molding depends on the blended ratio. At the time of de-molding,
the cross linking reaction is not completed yet, so the urethane elastomer
should be handled carefully.
1st aging at 110°C for 24-48 hours
After demolding, the urethane elastomer is placed in an aging oven
held at 110°C for 24-48 hours. The aging time depends on the kinds
of polyester or blending ratio, but 48 hours is enough for all formulation.
| Table
2 |
|
The effect of 1st aging time on the
physical properties of TODI based urethane elastomer
|
Polyester
R
NCO Index
Reaction time of
Pre-polymer
Catalysis |
Caprolactone
based
3.8
1.1
1.0
0.3 |
| 1st aging (Hours) |
24 |
48 |
72 |
| 2nd aging (Days) |
10 |
10 |
10 |
| Tensile strength (Kg/cm2) |
298 |
363 |
375 |
| Tearing strength (Kg/cm2) |
131 |
142 |
142 |
| 100% Modulus (Kg/cm2) |
109 |
111 |
114 |
| Elongation (%) |
560 |
600 |
600 |
| Hardness (ShoreA) |
95 |
95 |
95 |
|
2nd aging for 10 days
After finishing 1st aging, urethane elastomer is placed at room temperature
(>25°C) for 7-10 days. It should have final physical properties.
| Table
3 |
|
The effect of 2nd aging time on the
physical properties of TODI based urethane elastomer
|
Polyester
R
NCO Index
Reaction time of
Pre-polymer
Catalysis |
Caprolactone
based
3.8
1.1
1.0
0.3 |
| 1st aging (Hours) |
48 |
48 |
48 |
48 |
| 2nd aging (Days) |
4 |
6 |
10 |
40 |
| Tensile strength (Kg/cm2) |
337 |
357 |
363 |
369 |
| Tearing strength (Kg/cm2) |
137 |
139 |
142 |
141 |
| 100% Modulus (Kg/cm2) |
104 |
102 |
111 |
110 |
| Elongation (%) |
580 |
600 |
600 |
610 |
| Hardness (ShoreA) |
95 |
95 |
95 |
95 |
|
The physical properties of TODI urethane
elastomer
The physical properties of TODI urethane elastomer (Example 1 and
2) were measured by the analysis method of JIS-K-6301.
| Table
4 |
|
Comparison of physical properties among
various urethane elastomers
|
| Isocyanate |
TODI |
NDI |
| Polyester |
ODX-105 |
Caprolactone based |
ODX-105 |
Polyester
Diisocyanate
1.4 Butanediol
Catalysis |
100
25.7
3.6
No
|
100
33.3
5.1
No
|
100
38.5
7.6
No
|
100
25.9
2.9
No
|
100
33.7
5.2
No |
100
49.3
10.9
DABCO*1 |
100
25
5
N.A. |
100
18
2
NA |
R
NCO Index |
2.0
1.1
|
2.6
1.2 |
3.0
1.1 |
2.0
1.2 |
2.6
1.2 |
3.8
1.1 |
2.5
1.1 |
1.8
1.2 |
Pre-polymer
Reaction time (Hrs) |
2
|
2 |
2 |
2 |
2 |
1 |
0.07 |
0.07 |
| Pot Life (Sec) |
1120
|
300 |
160 |
2700 |
720 |
95 |
25 |
130 |
| 1st
aging at 110°C (Hrs) |
24
|
24 |
24 |
24 |
48 |
48 |
24 |
24 |
| 2nd aging (Days) |
10
|
10 |
10 |
10 |
10 |
10 |
10 |
10 |
| Tensile strength
(Kg/cm2) |
285
|
305 |
320 |
285 |
348 |
380 |
234 |
394 |
| Tearing strength
(Kg/cm2) |
65
|
97 |
103 |
68 |
88 |
145 |
131 |
104 |
| 100% Modulus
(Kg/cm2) |
36
|
61 |
77 |
30 |
62 |
110 |
85 |
53 |
| Elongation (%) |
900
|
820 |
760 |
660 |
590 |
560 |
720 |
800 |
| Hardness (ShoreA) |
81 |
88 |
93 |
80 |
88 |
95 |
92 |
83 |
| *1 0.3% DABCO
(triethylenediamine) |
|
The heat resistance and hydrolysis resistance
of TODI based urethane elastomer
The polyurethane elastomer based on TODI and Caprolactone Polyester
has superior heat resistance and hydrolysis resistance properties
than the polyurethane elastomer based on NDI polyester (Fig. 3 and
Fig. 4)
|
Fig. 3 Effect of high temperature aging on the physical
properties of three kinds of urethane elastomers (Heat
Resistance) |
|
 |
 |
 |
Change ratio
= f /f0, f0: Initial value, f: Value after the storage
in 120°C
TODI-M-103ES (R=3.8, NCO Index=1.1)
TODI-M-103ES (R=3.8, NCO Index=1.1)
NDI-ODX-105 (R=2.6, NCO Index=1.2) |
|
Fig. 4 Effect of high temperature and
high humidity on the physical properties of three kinds
of urethane elastomer (hydrolysis resistance)
|
 |
 |
 |
 |
Change
ratio = f / f0, f0: Initial value, f: Value after the
storage in 100°C and 100% humidity.
TODI-M-103ES (R=3.8, NCO Index=1.1),
TODI-M-103ES (R=3.8, NCO Index=1.1),
NDI-ODX-105 (R=2.6, NCO Index=1.2) |
|
Comparison of the Characteristics of Urethane
elastomer by different Polyol, isocyanate and cross-linking agent.
Materials for urethane elastomer are Polyol, Diisocyanate and Cross-linking
agent, and the physical and chemical characteristics of the urethane
elastomer are determined by the combination of these materials. Theoretically
there are many of the combinations of these materials for making urethane
elastomer, however, many of the combinations are failed to make in
the practical situation. The following tables are showing the basic
trend of the characteristics of urethane elastomer made by various
materials.
Polyol
Polyol is a relatively large molecule weight material for the urethane
elastomer (1000-2500), and is called soft segment because of its long
shape. Polyol is mainly divided into two groups, one is Polyether-Polyol
and the other is Polyester-Polyol. About 90% of the Polyol used in
urethane elastomer is Polyester-Polyol (85% is Polypropylene Glycol),
and the other 10% is Polyester-Polyol.
| Table
7-1 |
|
The influence of Polyol on the characteristics
of urethane elastomer
|
| |
Characteristics
of Urethane elastomer |
| Influence |
Big < ------------------------------------------
> Small |
| Type of Polyol |
Water Resistance |
Oil Resistance |
Chemical Resistance |
Cold Resistance |
| Ethyleneglycol
Adipic Ester (C2) |
D |
C |
B |
D |
| Ethylenbutanediol
Adipic Ester(C2,C4) |
C |
C |
C |
C |
| Butanediol Adipic
Ester (C4) |
B |
C |
C |
B |
| Propyleneglycol
Ether (C3) |
C |
D |
D |
C |
| Tetra-Methylen
Glycol Ether (C4) |
A |
C |
B |
A |
| Caprolactone
Ester (C5) |
B |
A |
B |
C |
| 3 Methyl-1.5pentan
Adipic Ester |
B |
C |
C |
A |
| Hexadiol Adipic
Ester (C6) |
B |
B |
B |
D |
| Carbonate Ester
(C6) |
A |
A |
A |
D |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
| |
Characteristics
of Urethane elastomer |
| Influence |
Big < ------------------------------------------
> Small |
| Type of Polyol |
Heat Resistance |
Hardness |
Flexural Strength |
Permanent Deformation |
Climate Resistance |
| Ethyleneglycol
Adipic Ester (C2) |
C |
A |
A |
A |
C |
| Ethylenbutanediol
Adipic Ester(C2,C4) |
C |
C |
C |
C |
C |
| Butanediol Adipic
Ester (C4) |
C |
C |
B |
C |
B |
| Propyleneglycol
Ether (C3) |
D |
C |
C |
D |
C |
| Tetra-Methylen
Glycol Ether (C4) |
C |
C |
B |
C |
A |
| Caprolactone
Ester (C5) |
B |
B |
C |
C |
B |
| 3 Methyl-1.5pentan
Adipic Ester |
C |
C |
A |
C |
B |
| Hexadiol Adipic
Ester (C6) |
B |
C |
C |
C |
C |
| Carbonate Ester
(C6) |
B |
B |
C |
C |
A |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
Diisocyanate
Diisocyanate is the small molecule weight material (150-300) and is
called hard segment. It forms the bone of Urethane elastomer and influences
the hardness, physical characteristics and heat resistance characteristics
of the urethane elastomer.
| Table
7-2 |
|
The influence of Diisocyanate on the
characteristics of urethane elastomer
|
| |
Characteristics
of Urethane elastomer |
| Influence to
Urethane elastomer |
Big < ------------------------------------------
> Small |
| Type of diisocyanate |
Hardness |
Heat Resistance |
Elastic Modulus |
Abrasion Resistance |
| TDI
(Tolylene diisocyanate) |
C |
C |
B |
C |
| MDI (Diphenylmethane
diisocyanate) |
B |
C |
C |
C |
| NDI (Naphthalene
diisocyanate) |
A |
B |
B |
B |
| TODI (Oltho-Tolidine
diisocyanate) |
B |
A |
C |
A |
| PPDI
(Para-phenylene diisocyanate) |
A |
A |
A |
B |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
| |
Characteristics
of Urethane elastomer |
| Influence to
Urethane elastomer |
Big < ------------------------------------------
> Small |
| Type of diisocyanate |
Light Resistance |
Flexural Strength |
Temperature Dependability |
Chemical Resistance |
| TDI
(Tolylene diisocyanate) |
C |
C |
C |
C |
| MDI (Diphenylmethane
diisocyanate) |
C |
B |
C |
C |
| NDI (Naphthalene
diisocyanate) |
D |
B |
A |
B |
| TODI (Oltho-Tolidine
diisocyanate) |
C |
C |
B |
B |
| PPDI
(Para-phenylene diisocyanate) |
B |
A |
A |
B |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
Cross-linking agent
Cross linking agent is less influential material for the characteristics
of urethane elastomer, and its molecule weight is small (60-200).
There are four types of cross-linking agents for urethane elastomer,
which are water, diol type, triol type and diamine type.
| Table
7- 3 |
|
The influence of Cross-linking agent
on the characteristics of urethane elastomer
|
| |
Characteristics
of Urethane elastomer |
| Influence to
Urethane elastomer |
Big < ------------------------------------------
> Small |
| Type of Cross
linking agent |
Heat Resistance |
Water Resistance |
Hardness |
Permanent Deformation |
| Water
(H2O) |
B |
B |
A |
A |
| Ethyleneglycol
(EG) |
B |
D |
B |
B |
| 1.4 Butanediol
(1.4 BD) |
C |
B |
B |
C |
| Trimethylolepropane
(TMP) |
B |
B |
C |
A |
| Methylene
bis oltho chlolaniline (MOCA) |
A |
A |
B |
B |
| Bishydroxyethyletherbenzen
(BHEB) |
B |
A |
C |
B |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
| |
Characteristics
of Urethane elastomer |
| Influence to
Urethane elastomer |
Big < ------------------------------------------
> Small |
| Type of Cross
linking agent |
Flexural Strength |
Cold Resistance |
Abrasion Resistance |
| Water
(H2O) |
B |
A |
A |
| Ethyleneglycol
(EG) |
B |
C |
B |
| 1.4 Butanediol
(1.4 BD) |
B |
B |
C |
| Trimethylolepropane
(TMP) |
D |
D |
C |
| Methylene
bis oltho chlolaniline (MOCA) |
C |
D |
B |
| Bishydroxyethyletherbenzen
(BHEB) |
D |
D |
C |
| A: Excellent,
B: Good; C: Fair; D: Inferior |
|
|
