Plasticizers fusion properties

Plastisol Fusion—This property is a function of temperature, time, and solvating power of the plasticizer. This property may be measured by determining the clear point, that is, the temperature at which a clear solution is obtained when a low concentration of resin is suspended in a plasticizer and heated at a constant rate. 

Historical Perspective General Theory of Plasticization Plasticizer Compatibility Compatibility Stability Fusion Properties of Plasticizers Plasticizer Concentration Effects Heat Stability Odor Development... 

The most commonly employed fillers in plasticized PVC are the precipitated forms of calcium carbonate (CaCOy) and related minerals such as dolomite (calcium magnesium carbonate). CaCOj fillers are diroated with fatty acids to improve physical properties of PVC, particularly flex life and elongation at break. The effect of calcium carbonate fillers on fusion properties of PVC is reviewed (47). Other fillers include china clay, calcined clay, asbestos, barytas, talc, alumina and kieselguhr and silicates. Micaceous-talc fillers in PVC which are polyblended with acrylonitrile rubber shows an extraordinary effect. Small amounts improve elongation and energy to break. 

Fusion Properties Fusion properties are governed primarily by plasticizer type and level as well as resin molecular weight. As the molecular weight of the resin increases, the fusion time increases. This is critical since the improved physical properties observed with higher-molecular-weight resins occur only when the higher-... 

Fusion Properties As with both flexible and rigid PVC, the higher the resin molecular weight, the slower the fusion. Plasticizer selection also plays a major role in plastisol fusion properties. PVC/vinyl acetate and other copolymer resin systems are sometimes used to speed fusion in plastisol systems. As the copolymer content increases, the rate of fusion increases. 

Eastman Plasticizer Technical Tip, Fusion Properties of Eastman Plasticizers vs. Hexamoll DINCH - US (TT-25), Eastman Chemical Company, November 2004. 

The widespread sales of this plasticizer are a redection of its all-around plasticizing performance and its provision of adequate properties for a great many standard products. It possesses reasonable plasticizing efficiency, fusion rate, and viscosity which, coupled with the normally competitive price, go a long way to explaining the popularity of this plasticizer. Some concerns have been periodically raised as to the possible toxicity of this material, but it can be said that these concerns are often related to the vast and widespread study of the toxicity of DEHP. 

Random copolymers of vinyl chloride and other monomers are important commercially. Most of these materials are produced by suspension or emulsion polymerization using free-radical initiators. Important producers for vinyl chloride—vinyUdene chloride copolymers include Borden, Inc. and Dow. These copolymers are used in specialized coatings appHcations because of their enhanced solubiUty and as extender resins in plastisols where rapid fusion is required (72). Another important class of materials are the vinyl chloride—vinyl acetate copolymers. Principal producers include Borden Chemicals Plastics, B. F. Goodrich Chemical, and Union Carbide. The copolymerization of vinyl chloride with vinyl acetate yields a material with improved processabihty compared with vinyl chloride homopolymer. However, the physical and chemical properties of the copolymers are different from those of the homopolymer PVC. Generally, as the vinyl acetate content increases, the resin solubiUty in ketone and ester solvents and its susceptibiUty to chemical attack increase, the resin viscosity and heat distortion temperature decrease, and the tensile strength and flexibiUty increase slightly. 

Verhage M, Maia AS, Plomp JJ, Brussaard AB, Heeroma JH, et al. (2000) Synaptic assembly of the brain in the absence of neurotransmitter secretion. Science 287 864—9 Wonnacott S (1997) Presynaptic nicotinic ACh receptors. Trends Neurosd 20 92-8 Weber T, Zemelman BV, McNew JA, Westermann B, Gmachl M, Parlati F, Sollner TH, Rothman JE (1998) SNAREpins minimal machinery for membrane fusion. Cell 92 759-72 Whittaker VP, Sheridan MN (1965) The morphology and acetylcholine content of isolated cerebral cortical synaptic vesicles. J Neurochem 12 363-72 Xu J, Mashimo T, Siidhof TC (2007) Synaptotagmin-1, -2, and -9 Ca2+ sensors for fast release that spedfy distinct presynaptic properties in subsets of neurons. Neuron 54 567-81 Zucker RS, Regehr WG (2002) Short-term synaptic plasticity. Annu Rev Physiol 64 355 405... 

During processing, the plastisol is heated slowly. When the gel point is reached, the plastic absorbs the plasticizer. However, in a very soft compound, the plastic dissolves into the plasticizer. Because each plastic particle remains a separate particle, the resultant gel has no useful physical properties. But on further heating, the plasticized plastic partially melts and flows into the plasticizer this occurs at the fusion point or over the fusion range. On cooling, the material comprises the tough rubber compound known as a flexible vinyl. 

Vinyl dispersions are fluid suspensions of special fine particle size polyvinyl chloride resins in plasticizing liquids. When the system is heated to about 350F., fusion (mutual solubilization of resin and plasticizer) takes place. The dispersion turns into a homogeneous hot melt. When the melt is cooled below 140F., it becomes a tough vinyl coating with excellent physical properties such as flexibility, abrasion resistance, chemical resistance and excellent aging. 

Pastry, Cake, and Biscuit Products. In general, fats play several essential nutritional, technological, functional, and organoleptic roles in most all-bakery applications. As a result of its physical properties, fat plays a major part in the production of the majority of items in the pastry, cake, biscuit, and chocolate confectionery sector for example, in the preparation of pastry cream and in the desired appearance and texture of the end product. These physical properties include, above all, the rheological properties (consistency, plasticity, texture, etc.), and the properties of fusion and crystallization depend on the type of fat, the temperature, and the working conditions of the product. 

Because of the importance of controlling the solid-state properties a great deal of interest has been generated around understanding the role of water in the formulation since water can act as a plasticizer that will deteriorate both chemical (i.e.. protein degradation) and physical (i.e., particle fusion, cake collapse, crystallization) stability. How dry this formulation needs to be depends on the glass transition of the formulation relative to the storage conditions and the so called zero temperature (55). 

Parenteral preparations are filled into various types of containers, depending on the nature of the product. Single-dose injections are filled into glass ampoules sealed by fusion or ex tempore into plastic syringes. Multidose injections are delivered in glass vials sealed with rubber closures with mechanical properties suitable for multiple piercing. Concentrates and powders for injections or infusions are also... 

---