Antioxidants rubber-based adhesives

Rubber base adhesives develop strength faster than most other polymeric types. Fig. 1 [3J shows the differences in the development of peel strength for several rubber polymers (without additional additives, except an antioxidant). Natural... 

ZDEC is used in the following applications as a fast primary or secondary vulcanization accelerator in NR, SBR, IIR, EPDM and for natural and synthetic latex a stabilizer in butyl, butadiene, and urethane rubbers an antioxidant in rubber-based adhesive systems a stabilizer in cement a heat stabilizer for polyethylene. 

Uses Nonstaining, nondiscoloring antioxidant for rubber goods, carpetbacking foams, laminating adhesives, SBR latex stabilization, rubber-based adhesives, footwear compds., mech. goods... 

Acrylic adhesives tend to be more stable than rubber-based adhesives since they have a saturated backbone. They are also generally designed so that they function as PSAs without the need for any tackification or plasticization, although tackifiers can be added to modify adhesion or reduce cost. Both of these features help to differentiate them from rubber-based PSAs. The ability to avoid use of tackifiers and antioxidants makes acrylics a good choice for medical applications where minimal skin irritation is desired. 

Formulation. Unlike the natural rubber pressure sensitive adhesives, acrylic adhesives are often supplied in a ready-to-use form. Natural rubber adhesives require time-consuming and costly mastication of the rubber followed by dissolving in solvent. In addition, they must be formulated with a tackifier resin and antioxidants, neither of which is required with an acrylic adhesive. The acrylic adhesives are known for their good UV and oxidative stability while the rubber-based adhesives, because of their chemical unsaturation, are poor in these properties. In general, tackifiers are not required with acrylic adhesives as tack can be designed into the polymer by the proper choice of... 

Uses Modifier of PP, PVC, PE, PS, and high-performance engineering resins antioxidant heat stabilizer UV stabilizer vise, depressant antiblocking agent in rubbers in adhesives for food pkg. emollient, protective film-former for skin in cosmetic creams and lotions used in hot-melt and solv.-based coatings textile/leather lubricants and finishes chemical intermediate defoamerfor pulp/paper processing... 

The causes of the adhesion failure of rubber-based pressure-sensitive adhesives were studied. The results showed that the resistance of adhesion failure decreased with increase in the amount of tackifier. The resistance of adhesion failure increased on addition of 0.5 to 1.0 phr of polyphenol antioxidant. The synergistic effect of oxygen and/or ozone in the atmosphere with UV light also led to failure of the adhesives. 

Standard-grade PSAs are usually made from styrene-butadiene rubber (SBR), natural rubber, or blends thereof in solution. In addition to rubbers, polyacrylates, polymethylacrylates, polyfvinyl ethers), polychloroprene, and polyisobutenes are often components of the system ([198], pp. 25-39). These are often modified with phenolic resins, or resins based on rosin esters, coumarones, or hydrocarbons. Phenolic resins improve temperature resistance, solvent resistance, and cohesive strength of PSA ([196], pp. 276-278). Antioxidants and tackifiers are also essential components. Sometimes the tackifier will be a lower molecular weight component of the high polymer system. The phenolic resins may be standard resoles, alkyl phenolics, or terpene-phenolic systems ([198], pp. 25-39 and 80-81). Pressure-sensitive dispersions are normally comprised of special acrylic ester copolymers with resin modifiers. The high polymer base used determines adhesive and cohesive properties of the PSA. 

Uses Antioxidant for protection of adhesives (esp. hot-melt and water-based), rubber, resins, other polymer systems, food-pkg. adhesives/coat-ings/polymers... 

Uses Antioxidant, antiozonant for petroleum-based and synthetic lubricants, rubbers, and plastics (PU) scorch retarder for CR in food-pkg. adhesives in closure-sealing gaskets for food containers antioxidant/stabilizer for food-grade polymers, pressure-sensitive adhesives antioxidant in food-contact rubber articles for... 

The most recent development in pressure-sensitive tape manufacture is the development of the hot-melt coating process. Almost aU of the current hot-melt applied adhesives (see also Hot-melt adhesives) are based on SIS thermoplastic rubber, mixed with hydrocarbon tackifier resins and oils in substantial amounts, and an antioxidant in minor amounts. 

Oxygen in the atmosphere generally attacks polymers. In many cases, the rate of attack, even at ambient temperatures, necessitates the use of stabilizing additives. Examples of adhesives that normally contain antioxidants are hot-melts, those based on natural and synthetic rubbers, and pressure-sensitive adhesives. 

---