Polyurethane Elastomers Advantages
 
     
 

Johnson urethane elastomers contain both the rigidness of plastics andthe toughness of rubbers making them ideal for engineering materials.

  
 

mechanical properties

  
 

1 .High resistance on abrasion and wear
Urethane elastomers exhibit excellent abrasive resistance. Under the same laboratory conditions, PU Elastomers can be thrice or ten times than conventional rubbers and plastics.

2.High tensile strength
Some plastics have high tensile strength properties but low elongation. Most rubber materials have high elongation but low tensile strength. Urethane elastomers have both high tensile stress and high elongation properties.

  
 
 
 

3.High load-bearing capacity
Urethane elastomers have greater load-bearing capacity than the other elastomers of comparable hardness and elasticity. This allows design of small parts with resulting in saving weight and material costs.

4. High Impact Resistance
Urethane eIastomers have Significantly better impact resistance than structural plastics many times. And urethane elastomers including the hardest type, exhibit excellent low temperature impact resistance and low brittle points.

  
 
 
 

5.High Vibration and damping characteristics
According to the application, urethane rubbers can be formulated to exhibit low or high resilience. Since urethane elastomers contain no fillers or plasticizers, they can be compounded to maintain a high degree of resilience over a Wider range of hardness than the other elastomers.

6. High resistance to oxygen, ozone, oils and Solvents
The oxygen and ozone resistance of urethane elastomers are excellent because of the absence of olefinic bonds. The oxygen absorption of a polyester-urethane has been found to be quite low and oven aging had little effect, compared with to nature rubber. Urethane rubbers are resistant to the attack of many chemicals. They exhibit excellent resistance towards aliphatic solvents, ethers, most petroleum-base. Fuels and oils, hydraulic fluids and others. Neoprene offer oil resistance but lack tear and abrasive resistance. Polyester base urethanes generally provide an advantage over neoprene in all three areas. Protection from oil swell is provided as well.

  
     
 

Comparison of URETHANE ELASTOMERIC Material with Conventional Materials

Environment

Polyester Urethane

Polyether Urethane

Natural Rubber

Neoprene Rubber

Heat
Cold
Weather
Ozone Resistance

G
G
E
E

F
G
E
E

F
E
P
P

G
G
G
F

ASTM No. 1 Oil
ASTM No. 3 Oil

E
E

F
P

P
P

G
G

Aliphatic solvents e. g. Heptanes

E

F

P

G

Chlorinated Solvents e. g. Trichloroethane

F-G

P

G

P

Aromatic Solvents e. g. Toluene 

F

P

P

F

E-excellent G-good   F-fair   P-poor                                    

 
     
 

7. Electrical Properties
The electrical properties of urethane elastomers are good and about the same order of magnitude as those of phenolic resins. It has been used successfully in potting and encapsulation compositions at frequencies up to 100 kilocycles and at temperatures up to 212 oF

8. Miscellaneous Properties

  1. The machine ability of hard compounds of urethane elastomers approaches that of same metals and is similar to many plastics. It can be readily drilled, routed, sawed, or turned and shaped.
  2. The translucence of unpigment urethane is an extra vantage in certain applications such as potting and encapsulating. Opaque, black or colored products of urethane elastomers are commonplace.
  3. Urethane eIastomers absorb water less than that of Nylon.
  4. Urethane elastomers offer the greatest resistance to the damaging effects of gamma ray radiation of all the many elastomers and plastics.
  5. Standard compounds of urethane elastomers are generally resistant to fungus attack and mildew growth.
Comparison with other materiaIs		  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
     
 
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