Polyvinylchloride formulation

Phthalate esters are widely used as industrial solvents and plasticizers in the manufacture of different plastics. Di-2-ethylhexyl phthalate, the most commonly used phthalate ester in polyvinylchloride formulations, can constitute up to 40 % of the end product. (Autian 1973). Phthalate esters have been recognised as environmental pollutants (Overturf et al. 1979). Di-2-ethylhexyl phthalate is a representative of peroxisome proliferators in rodents, and also induces enzymes specific for other organelles, DNA synthesis and organ growth (Huber et al. 1996). 

The backing material and release liner can be fabricated from a variety of materials including polyvinylchloride, polyethylene, polypropylene, ethylene-vinyl acetate and aluminium foil. The most important property of these materials is that they are impervious to both drug and formulation excipients. The most useful backing materials conform with the skin and provide a balanced resistance to transepidermal water loss, which will allow some hydration of the stratum corneum, yet maintain a healthy subpatch environment. The release liners are usually films or coated papers and must separate easily from the adhesive layer without lifting off any of the pressure-sensitive adhesive. Silicone release coatings are used with acrylate and rubber-based adhesive systems, and fluorocarbon coatings with silicone adhesives. 

Perrilla ketone Drug formulated in propylene glycol, ethanol, and water to be diluted in a parenteral emulsion before IV administration. IV administration in 5% dextrose led to loss of 20-60% drug by adsorption to the polyvinylchloride (PVC) of the infusion tubing. This problem was overcome in IV emulsion formulation... 

Polyvinylchloride is the prime example of a polymer whieh produces the degradation product, HCl, which is potentially dangerous to the stability of plasticizers. Sinee plasticizers are esters they may undergo hydrolysis assisted by acids. Figure 10.41 shows acid number of plasticizers in simple PVC formulation heated at 170°C for 90 min. The rate of hydrolysis depends on plasticizer type (both acid and alcohol seem important). 

Compared with HOCl, iodophores are not as readily degraded by organics and are nonirritating (at recommended levels). Ig becomes volatile at >120°F (49°C). Formulations containing iodophores may stain polyvinylchloride and other surfaces. 

Campbell and co-workers [62] carried out a systematic study of the thin-layer separation of the plasticiser mixtures used in polyvinylchloride (PVC) formulations. 

MTTP-TSE Process To completely overcome worries with VOC emissions and reduce the danger of fire in production, Nielson has invented magne-sium/fluorocarbon formulations based on thermoplastic polymers (TPs) called MTTP [23-25]. Initially polystyrene was considered as material of choice but in subsequent was substituted by polyvinylchloride-polyvinylacetate copolymer (PVC-co-PVAc), which shows lower softening temperature. The softening agent... 

With increasing amount of air mixed with the primary combustion products, the HF concentration decreases as is depicted for the three flare formulations in Figure 20.2. The investigation of HF formation on combustion of a payload similar to MTV-3 had been carried out in Ref [4]. The combustion had been carried out in a combustion chamber of 3.6 m volume lined with chlorinated polyvinylchloride (PVC). Fragments of either 12 and 25 g mass were burned and yielded between 1.41 and 3.88 mg HF per gram of MTV [4]. 

While the polyvinyl acetate-based emulsions have multiple applications (office glues, wood glues, packaging industry, etc.), the acrylic emulsions are used mainly for the production of autoadhesive films and tapes or for other labels (see PSAs part) their main value therefore lies in the large variety of formulations accessible (using variable composition copolymers) and in the good tolerance they demonstrate toward the plasticizers present in certain substrates (bonding of polyvinylchloride films for example). 

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