Volatility of the plasticizers in question is reduced in the DBR DBS, LZ-7 and DBEA series, the values for the above products being 15.2, 6.9, 5.8 and 1.03% by weight, respectively.
DBEA parameters tested confirm high effectiveness and low-temperature resistance of the plasticizer.
When DBEA is used in rubber recipes based on NBR-18, NBR-28 and NBR-40 rubbers instead of DBP, LZ-7 and DBS, DBEA is rather effectively distributed in rubber compounds and there is no plasticizer migration both to the surface of rubber compounds and cured products during an extended storage period.
It has been found that NBR modified at the latex stage with the DBEA plasticizer confers higher processability to rubber compounds (figure 3).
Low temperature resistance of DBEA containing rubber compounds greatly exceeds that of DBP compounds, and is on a par with compounds with LZ-7 ester.
In case the rubber compound recipe contains the combination of DBP and DBS, the DBEA plasticizer can replace DBS or both plasticizers.
It should be noted that oil resistance and low-temperature resistance of standard rubber compounds increases with higher DBEA content in NBR-18 rubbers.
The optimum DBEA plasticizer content that ensures the needed increase of NBR low-temperature, oil and heat resistance for rubber product manufacturing should be selected within the range of 3 to 15% by weight, depending on the rubber item's purpose and application.
A higher level of rubber low-temperature resistance is achieved when NBR-18 rubber is used with a DBEA content of at least 8% by weight (figure 4).
It was shown that DBEA is the most effective plasticizer to enhance both low-temperature resistance and processability.