18 сентября, 2015 
Malyar Various dispersions are available which even in unmodified form exhibit aggressive tack and good adhesion, especially to polar substrates. Produced by conventional emulsion polymerization techniques, the tack, peel, and shear properties of these dispersions can be varied within wide limits by the choice of monomers. A dispersion will usually consist of at least two monomers, one of high glass transition temperature (Tg) and the other with a low Tg value, and the ratio of the two will determine the final properties of the film. Table 1 lists the Tg values of monomers in common use.
Cross-linkable monomers may be included to make the formulated adhesive curable by catalysis, heat, or radiation, thereby improving the performance of the film, especially at higher temperatures. Since the dispersion has both toughness and tack built in, no further compounding is necessary, making pressure-sensitive acrylic dispersions the easiest products to work with. In most applications, however, the formulator will prefer to modify the properties to order, and use of tackifying resins added either in solution or as a dispersion is common. Vinyl ethers can again be used either as sole binders or as tackifiers to modify the properties of the base dispersion.
Water-based systems have good aging characteristics, resisting the effects of heat, ultraviolet (UV) light, and oxidation. Thus use of antioxidants is not normally necessary. Table 2 lists the major advantages and disadvantages of the various types of pressure — sensitive adhesives.
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