The so-called wax means that the polymer is finally distributed in the surface layer of the paint in the form of microcrystals, which plays a role similar to paraffin but more diverse and practical than paraffin. The main functions of polyethylene wax in solvent-based coatings are: matting, anti-scratch, anti-wear, anti-polishing, anti-marking, anti-adhesion, anti-sedimentation, thixotropy; good lubricity and processability; positioning of metallic pigments.
(1) Molecular weight. The molecular weight of Fischer-Tropsch wax is much lower than that of PE wax, with fewer branched chains and high crystallinity. It is easy to penetrate into high-viscosity macromolecular chains, significantly reduces melt viscosity, has little migration during processing, and has obvious lubricating effect in the later stage.
(2) Fischer-Tropsch wax is a saturated straight-chain alkane without double bonds, with strong oxidation resistance and good weather resistance.
(3) The viscosity of Fischer Tropsch wax is much lower than that of PE wax. Only around 10. The same lubricating effect can be achieved with less dosage. The amount used is only 70%-80% of PE wax. Fischer-Tropsch wax has good compatibility with PVC, and can be used as an internal and external lubricant. It can be used as a good internal lubricant to effectively control shear conditions, promote flow, control friction and melting properties, thereby improving thermal stability. At the same time, due to its high crystallinity and high linearity structure, Fischer-Tropsch wax enables PVC products to obtain the best physical and processing properties. According to needs, the Fischer-Tropsch process can synthesize alkanes with different chain lengths to change the molecular weight of the final product to form a series of products.
Hot-melt adhesives are favored because their products are solid, easy to pack, transport, store, solvent-free, non-polluting, non-toxic, simple production process, high added value, high bonding strength, and fast.
The basic resin of hot melt adhesive is the copolymerization of ethylene and vinyl acetate under high temperature and pressure, that is, EVA resin. This resin is the main component of making hot melt adhesive, the proportion and quality of basic resin determine the basic performance of hot melt adhesive. Secondly, the selection and use of tackifiers, viscosity modifiers, and antioxidants are also very important. In the application of hot melt adhesives, the use characteristics of Fischer-Tropsch wax are as follows:
(1) Without any pollution and taste, it can be directly used in the food contact hot melt adhesive industry.
(2) It has a higher freezing point, which can improve the heat resistance of the hot melt adhesive.
(3) The needle penetration is small, which can improve the strength of the hot melt adhesive.
(4) The carbon distribution range is relatively narrow, the opening time is relatively small, and the curing time is short.
Fischer-Tropsch wax is an ideal synthetic wax for EVA-based hot melt adhesives. It can effectively improve the heat resistance and quick drying of the adhesive.