Butyl rubber has isoprene in its macromolecule and introduces a small amount of double bonds that can be vulcanized to form crosslinks. However, the polybutene structure cannot be vulcanized due to the absence of double bonds. Both of these polymers have good weather resistance and chemical resistance, and have low gas permeability. Since the polarity is small, despite its high viscosity, the chemical attraction to the surface of the material is weak, so it must be mixed with the resin that can impart polarity.
They are used as tackifiers in adhesives, pressure sensitive adhesive tapes, hot melt adhesives, and sealants, and can also be used as a raw material for sealing layers around automotive windows.
Chlorinated butyl rubber can be prepared by chlorinating butyl rubber under certain conditions. In this reaction, the chlorine atom enters the allyl position, taking away one carbon atom from the double bond, and the macromolecule reduces the unsaturation. In chlorinated butyl rubber, the chlorine content is about 1.2% by weight, and its presence helps to increase the reactivity of the double bond and provide a site for addition reaction of the crosslink, thereby producing different types of vulcanized rubber.
Chlorobutyl rubber can be easily mixed with other more highly unsaturated elastomers such as butyl rubber or natural rubber to increase strength. In addition, the presence of reactive chlorine increases the adhesion to polar substances.
This paste was applied to an ethylene-propylene-diene copolymer rubber containing peroxide, covered with a cotton cloth, and pressed at 160° C. for 30 minutes. The peel strength was 18 kg/25 cm.
Butyl rubber solution adhesives can also be divided into single-component or two-component, low-temperature curing or high-temperature curing. The solid component is usually mixed with rubber and then dissolved in a solvent to make a solution.
Butyl rubber latex was prepared using an anionic emulsifier, containing about 63% solids, a pH of 5.5, and an average particle size of 0.3 microns. To which butylated hydroxytoluene is added as an antioxidant, a small amount of formaldehyde is sometimes added as a preservative. This latex film has good mechanical strength, chemical resistance and freeze-thaw stability, and can be widely used with other groups. Mixing. Due to the good stability of the latex, it cannot be coagulated with the usual emulsion coagulant.
Butyl rubber emulsions can be used directly as packaging adhesives, or as thickeners or softeners to improve the performance of brittle resin adhesives because of its good adhesion to polyolefin films and fibers, etc. It can be used as a laminating adhesive and seam adhesive, or as a special adhesive and coating for polyethylene and polypropylene.