From 09/23/2014 through 7/10/2012
1. “Polyvinyl chloride (commonly referred to as "PVC") has been used for a number of years in the manufacture of soft, flexible films for food packaging, in molded rigid products (such as pipes, fibers, upholstery and bristles), and in a variety of other products, including electric wire and cable-coverings, film finishes for textiles, raincoats, belting, gaskets and shoe soles. A variety of plasticizers have been used to produce flexible PVC articles. The plasticizer compounds differ in many respects but all of them must possess certain characteristics. For example, the plasticizer compound must be compatible with the PVC resin and render the PVC more flexible and/or softer. In PVC, the plasticizer also assists in the fusion of the PVC formulation to produce the final article. In the typical fusion process, the PVC resin particles dissolve and/or break apart, intermingle with all the other additives to produce the final homogenously mixed material. Plasticizers that have a high affinity for PVC resin resulting in very quick fusion are called high-solvating plasticizers. Fusion in dry blends is accomplished by a combination of stress and temperature. Fusion in plastisols occurs mainly by temperature. There are a number of chemical classes of high-solvating plasticizers such as benzoates, butyl benzyl phthalate, dihexyl phthalate, and others. High-solvating plasticizers provide faster fusion allowing fusion to occur at lower temperatures or to occur faster at a given temperature. A disadvantage for plastisols is high solvating plasticizers are typically not as stable to viscosity increases as general purpose plasticizers.” [Plasticizers, US Patent 8,372,912 (2/12/2013)]
2. ”Plasticizers (UK = plasticisers) or dispersants are additives that increase the plasticity or fluidity of a material. The dominant applications are for plastics, especially polyvinyl chloride (PVC). The properties of other materials are also improved when blended with plasticizers including concrete, clays, and related products. The worldwide market for plasticizers in 2000 was estimated to be several million tons per year.
Plasticizers for plastics are additives, most commonly phthalate ester. Almost 90% of the market for plasticizer is for PVC, giving this material improved flexibility and durability. Plasticizers work by embedding themselves between the chains of polymers, spacing them apart (increasing the "free volume"), and thus significantly lowering the glass transition temperature for the plastic and making it softer. For plastics such as PVC, the more plasticizer added, the lower its cold flex temperature will be. This means that it will be more flexible and its durability will increase as a result of it. Plasticizers evaporate and tend to concentrate in an enclosed space; the "new car smell" is caused mostly by plasticizers evaporating from the car interior.
Plasticizers make it possible to achieve improved compound processing characteristics, while also providing flexibility in the end-use product. Ester plasticizers are selected based upon cost-performance evaluation. The rubber compounder must evaluate ester plasticizers for compatibility, processibility, permanence and other performance properties. The wide variety of ester chemistries that are in production include sebacates, adipates, gluterates, phthalates, azelates, and other specialty blends. This broad product line provides an array of performance benefits required for the many elastomer applications such as tubing and hose products, seals and gaskets, belts, wire and cable and print rolls. Low to high polarity esters provide utility in a wide range of elastomers including nitrile, polychloroprene, EPDM, chlorinated polyethylene, and epichlorohydrin. Plasticizer-elastomer interaction is governed by many factors such as solubility parameter, molecular weight and chemical structure. Compatibility and performance attributes are key factors in developing a rubber formulation for a particular application.
Plasticizers also function as softeners, extenders, and lubricants, and play a significant role in rubber manufacturing.”
(Wikipedia, Plasticizers, 7/10/2012)
3. Epoxidized vegetable oils have been used in small proportions as secondary plasticizers and thermo-costabilizers in the production of flexible, semi-rigid and rigid polyvinyl chloride (PVC) materials. However, the use of epoxidized triglycerides as primary plasticizers results in exudation due to limited compatibility with the polymeric matrix. Cordeiro et al developed compatible plasticizers for vinyl polymers by transesterification of vegetable oils and alcohols catalyzed by an alcoxide generated by the reaction of an alcohol with an alkaline metal.
US Patent 8,802,877 (August 12, 2014), “Process for Modifying Vegetable Oils and Primary Plasticizer for Vinyl Polymers,” Milton Sobrosa Cordeiro, Sergio Teixeira, and Ariovaldo Fernandes Junior (NPC Industrias Quimicas Ltda., Mogi das Cruzes, Brazil).
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
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* Date of latest addition; date of first entry is 7/10/2012.