When choosing antioxidant pay attention to the cooperation between antioxidants, antioxidant and other thermal and light stability agent cooperation.Specific content is as follows:
(l) and the effect.
With a variety of antioxidants, can carry on their respective characteristics and effect, increasing the total effect.Such as different evaporation degree or space steric hindered phenolic and use, can promote them in the wide temperature scale, the antioxidant effect of strengthening effect.If in the formula, use only one kind of antioxidant, must attend the amount is larger, in high concentrations can cause intense oxidation reaction, it is not allowed.But when choosing several kinds of low concentration of antioxidants and, not only can reach the intention of demand, also to prevent oxidation, carry forward its plus and effect.
(2) the synergy effect.
(1) when two different activity of the main antioxidant and, highly active of antioxidants, hydrogen atom is given, and the activity of oxidation occurred chain to stop;And low activity of antioxidant can give highly active antioxidant supply of hydrogen, make its regeneration and promote durable antioxidant effect, thus antioxidant effect is very good.
(2) the main and auxiliary antioxidants and, attention should be paid to promote synergy.Simple as the main antioxidant given hydrogen atoms, can make the superoxide free radical into hydrogen peroxide, stop the chain reaction;Then hydrogen peroxide and auxiliary antioxidant effect of peroxide differentiation, generating inactive safe products.Thus slow oxidation reaction speed, greatly added antioxidant effect.
(3) a kind of antioxidant molecules has two or more different safe function, according to the synergistic effect, such as sulfur hindered phenolic antioxidant, has a chain reaction stop agent and peroxide differentiation effect of two layers, the antioxidant can strengthen antioxidant effect, is the ambition of antioxidants.
(4) antioxidant and thermal and light stability agent and, should choose have a synergistic effect, and makes every effort to prevent has the opposite effect.As most of the amine and phenolic antioxidant, when there are black carbon in significantly lower efficiency, has the opposite effect, this may be due to the oxidation of carbon black direct catalytic antioxidants, take out some antioxidants.Antioxidant containing thioether bond with carbon black have synergy effect,so there will choose the later.