Ethylene vinyl acetate system

Marosfoi, B. B., Marosi, G., Szabo, A., Vajna, B., and Szep, A. 2007. Laser pyrolysis microspectros-copy for modelling fire-induced degradation of ethylene-vinyl acetate systems. Polymer Degradation and Stability 92 2231-2238. 

Poly(ethylene-co-vinyl acetate)-ethylene-vinyl acetate system, 80 Polyisobutylene, 66, 192 surfactant, 278-279 Polyisobutylene-succinic anhydride copolymer fractions, 279 Polymers... 

Ethylene Vinyl Acetate System. The first new lamination material developed by t SA was compounded by Springborn Laboratories Inc. (SLI) from an ethylene vinyl acetate (EVA) feedstock available from Du Pont. Compared with PVB, EVA costs about one-third as much, has much lower viscosity at process temperature, and has no humidity-control requirement during processing. 

In 1976, Langer and Folkman published a landmark paper in which several polymer systems were studied with respect to biocompatibility and sustained release of macromolecules. Ultimately, they determined that two of the polymer systems were most biocompatible. Pellets made from casting of ethylene-vinyl acetate copolymer (EVAC) showed no significant inflammation after implantation as did the pellets cast of Hydron, a polymer of hydrox-yethylmethacrylate. In terms of in vitro release kinetics, while both polymer systems exhibit a significant initial release (i.e., "burst kinetics"), the ethylene-vinyl acetate system had a slower overall release profile that persisted significantly longer, making it more ideally suited for the in vivo release of macromolecules. As a way to further retard the rapid release of the proteins. 

Hot melt adhesives are also high solid systems which can meet environmental requirements. Thus, the growth of hot-melthas been projected to double by 1980 (Fig. 6). It is likely that new hot-melt systems will be introduced to the market. To demonstrate the promising features of hot-melt, we choose the ethylene-vinyl-acetate system (EVA) as an example. EVA can be formulated with a tackifier and a wax. The formulation can be facilitated with the use of computer to plot the viscosity-composition profile. 

Uses Defoamer/antifoamer for aq. systems, coatings, adhesives, food-contact coatings defoamer for PVAc, ethylene-vinyl acetate systems food-contact adhesives, paper/paperboard... 

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

Although current matrix diffusional systems are most suitable for small-molecule compounds, it has been demonstrated (84) that soHd hydrophobic polymers allow dispersed powdered macromolecules of nearly any size, for example, ethylene—vinyl acetate copolymers containing dispersed polypeptides, to be released for periods exceeding 100 days. 

Ethylene-vinyl acetate copolymers have been available for several years from Bayer (Levapren 450) and these contain about 45% of vinyl acetate units. As with EPM these rubbers cannot be cured with accelerated sulphur systems but by peroxides. 

The hormone-releasing devices have a closer resemblance to standard methods of sustained release because they involve the release of a steroid compound by diffusion [198,199]. The Progestasert, a reservoir system, is shown in Fig. 16. Progesterone, the active ingredient, is dispersed in the inner reservoir, surrounded by an ethylene/vinyl acetate copolymer membrane. The release of progesterone from this system is maintained almost constant for 1 year. The effects of release are local, with none of the systematic side effects observed with orally administered contraceptives [200-207]. 

Fig. 11 illustrates the smoke suppression effect of the zinc borate when used in conjunction with ATH in a halogen-free ethylene-vinyl acetate (EVA) system. Sumitomo Electric, in a... 

Dispersion, Flaring, Scrubbing, and Containment An example of an overpressure protection system designed to reduce emissions to the atmosphere and at the same time provide adequate protection to the equipment has been described [234]. The equipment indicated is used for the manufacture of ethylene-vinyl acetate-vinyl chloride polymer emulsions. The design pressures are up to 100 bar. 

Disclosed are ethylene-vinyl acetate/ethylene-styrene interpolymer blends, which are useful in preparing foams exhibiting improved compression set resistance, dimensional stability and rebound resilience at similar foam densities than known foam systems, e.g. EVA. The crosslinked foams are particularly useful in fabricating footwear and gaskets. 

Latexes are usually copolymer systems of two or more monomers, and their total solids content, including polymers, emulsifiers, stabilizers etc. is 40-50% by mass. Most commercially available polymer latexes are based on elastomeric and thermoplastic polymers which form continuous polymer films when dried [88]. The major types of latexes include styrene-butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyacrylic ester (PAE) and epoxy resin (EP) which are available both as emulsions and redispersible powders. They are widely used for bridge deck overlays and patching, as adhesives, and integral waterproofers. A brief description of the main types in current use is as follows [87]. 

Figure 2 Digital image from an ethylene-vinyl acetate/lysozyme chloride drug delivery system. The pore space has been opened, the polymer stained light gray, and residual protein stained black.

CIL has influence on fire-retardant systems through viscosity as well. Nonmodified montmoril-lonite (NMM) and organophilic montmorillonite (OMM) have been introduced into ethylene vinyl-acetate (EVA) copolymer (clay content was 10%) and compared in AR 2000 type rheometer. (Measurements were performed at 210°C and 0.5% amplitude. The applied frequency range was co = 1-600 1/s.)... 

Laoutid F, Gaudon P, Taulemesse JM, Lopez Cuesta JM, Velasco JI, Piechaczyk A. Study of hydromagnesite and magnesium hydroxide based fire retardant systems for ethylene-vinyl acetate containing organo-modified montmorillonite. Polym. Degrad. Stab. 2006 91 3074-3082. 

---