Self-adhesive modified asphalt adhesive is an important raw material for the production of modified asphalt waterproofing roll-roofing. It has the advantages of high strength, elongation, good adhesion, excellent low-temperature flexibility, self-healing, easy and fast construction, etc.
The impact of components and adjustments.
Asphalt ductility and the amount of wax additve has an important impact on the bonding performance, in addition to the requirements of asphalt at 25 ℃ ductility greater than 100cm, the wax content should not be too much, otherwise it will directly affect the bonding. In addition, the solubility of asphalt also has a certain impact, the asphalt used should not contain too much asphaltene and free carbon and mechanical impurities, to ensure the adhesive bonding.
When using SBS modified asphalt, asphalt and SBS miscibility is more important. The so-called good miscibility, that is, the asphalt selected with a moderate melt index of SBS modified more ideal. SBS is styrene (S) and butadiene (B) block copolymer, in which butadiene is a soft segment, is a continuous phase; both ends of styrene (S) is a hard segment, which aggregates into a physical cross-linked area. The block ratio (S/B) is different, which has a certain influence on the bonding performance.
The molecular structure of rosin has both hydrogenated phenanthrene nuclei that are well compatible with hydrocarbons and contains high polarity carboxyl groups, so it has good compatibility with elastomers. Rosin has good viscosity building effect, but because the resin acid of rosin contains conjugated double bond, high solid reactivity, unstable and easy to oxidation.
b. Terpene Resins
Polyterpene resins used as tackifier are mainly a-pinene or ? -pinene resin, its solubility and compatibility is less than rosin, especially the high softening point of the resin to the molecular mass of polydispersed polymer compounds lack of compatibility, but with SBS asphalt can still be very compatible, but compared with rosin, terpene resin viscosity is slightly worse, but its good oxygen resistance, excellent heat resistance.
c. Petroleum resins aromatic petroleum resins and SBS compatibility is poor, generally not used as a tackifier. Can be used as a tackifier is mainly aliphatic petroleum resins, but its tackifying effect is not as good as rosin and terpene resin.
The best choice is to use the active filler after surface treatment. Because the surface of the active filler particles can be combined with polymer chains to form a cross-linked structure, when one of the molecular chain under stress, the stress can be transferred to other molecular chains through the cross-linked point of dispersion; if one of the chains break, the other chains can still work, without immediately endangering the whole, so it can improve the mechanical properties of modified asphalt.
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