Brief Introduction of Tackifying Resin
Rrubber tackifying resin are:
coumarone indene resin, rosin resin, terpene resin, alkyl phenolic resin and petroleum resin.
In application of radial tire, mainly are modified rosin resin, petroleum resin and alkyl phenol formaldehyde resin.
Petroleum resin as a tackifier for use are C5 and C9 mainly.
They have replaced coumarone indene resin.
C5 is widely used as a tackifier. C9 aromatic hydrocarbon resins is used as both reinforcing and tackifying.
Phenolic tackifying resin:
Thermoplastic alkylphenol formaldehyde resins, or acetylene, are known as non-reactive resin.
By changing the alkyl substituents,the characteristics of these resins can be adjusted.
Molecular weight and polymerization reaction conditions has important implications on the nature of these resins.
Non-reactive phenolic tackifying resin can be applied to SBR, NR, BR, IIR and EPDM.
Adding these resins, one can improve the compound’s viscosity, with the physical properties of rubber remained unchanged.
Concerning viscosity enhancement effect from the overall performance viewpoint, best is alkyl phenolic resins. Main difference with petroleum resin is that alkyl phenolic resin can enhance and maintain the viscosity at high temperatures, under high temperature and humidity, with aging of the rubber,the increase of the viscosity is more effective.
Based on different substituents, phenolic resin can be divided into tert-octyl phenol formaldehyde resin and tert-butyl alkyl phenolic resin. And By each the same substituent, there are different molecular weight and molecular weight distribution.
Some consideration in applying phenolic tackifiers:
(1)Tackifier has little effect on physical properties of the compound, but will reduce certain elongation and flex of the compound.
(2)The use of tackifying resin has some impact on rubber vulcanization rate, and decrease the Mooney viscosity.
(3)By the use of tackifier, the compound have increased in viscosity. The best are 204 resin and 203 resin. 207 resin and RX280 resin are not as good. 203 resin can maintain a good viscosity with different kinds of rubber and plastic materials.
(4)Using the 204 resin produce although higher self-adhesive rubber, but not as good viscosity with other rubber materials, and it is easier to stick to roller at a higher temperature; while the 203 resin works good by either self-adhesive or interaction.
Therefore, compound 203 resin is a better alternative.
At present, by China radial tire application, two main tackifier are used tert-butyl phenol formaldehyde resin (C4 resin) and tert-octyl phenol formaldehyde resin (C8 resin).
Phenolic resin tackifiers can improve adhesive properties between the fiber and rubber, and also the steel cord and rubber adhesion.