Stabilizer/plasticizers, epoxy

Following the successful development of epoxidized soybean oil( 5), mainly as a stabilizer adjuvant with high permanence but poor low temperature plasticizing properties, the epoxidized fatty acid esters were introduced. These included the C8 mono-hydric alcohol esters — octyl epoxystearate and octyl epoxy-tallate. They also acted as stabilizer adjuvants but with outstanding low temperature plasticizing properties. The epoxy stabilizer/plasticizers have grown to over 50,000 tons/year in the U.S. in 1978, with the epoxidized soybean oil type predominating. 

The demands on insulating materials in soil and fresh water are relatively low. Anodically evolved oxygen makes the use of aging-resistant insulating materials necessary. These consist of special types of rubber (neoprene) and stabilized plastics of polyethylene, and polyvinylchloride, as well as cast resins such as acrylate, epoxy, polyester resin and many others. 

The manufacture of epoxy stabilizers begins with soya and linseed oils or oleate and other unsaturated fatty acid esters. When epoxidation is incomplete, residual unsaturation remains, leading to poor compatibility-stability. This results in exudation on products in the marketplace. Makers of epoxldized fatty acid esters strive to prevent such failure by ensuring more complete epoxidation and supplying products with the lowest possible iodine number. Vinyl formulators further protect themselves by diminishing the proportion of epoxidized stabilizer to an amount ca. 3% while maintaining plasticizer concentration at ca. 35%. 

Aliphatic esters are diesters of adipic, sebacic or azelaic acids and offer greater resistance to low temperatures than phthalates, but at a higher cost Epoxy ester plasticizers have limited compatibility with PVC so are used at low concentrations. The most widely used epoxy ester plasticizer is epoxidized soya bean oil (ESBO). ESBO resists extraction, does not migrate readily and acts also as a heat stabilizer. Other plasticizers in this group include epoxidized linseed oil and tall oil. 

Uses Plasticizer/stabilizer for epoxy, PVC, paints plasticizer/synergist for PVC heat stabilizers plasticizer in food-contact polymers coupling agent for S/B block copolymers pigment dispersant in PVC-P in closure-sealing gaskets for food containers in food-contact polysulfide polymer/polyepoxy resins... 

Epoxy stabilizer (epoxides stabilizer) n. Most epoxy plasticizers also serve as stabilizers because of the ability of the epoxides group to accept HCl, or to serve as an intermediate, in the presence of metallic salts, to convert HCl to a metallic chloride. Epoxy stabilizers are most often used in conjunction with barium-cadmium and other stabilizers, with which they have a synergistic effect. 

Thousands of compounds have been proposed as heat stabilizers and as combination heat and light stabilizes for various plastics. The principal classes of such compounds are (1) Group II metal salts of organic acids (primarily the barium, cadmium, and zinc salts of fatty acids, and phenols, the most important group). (2) Organotin stabilizers. (3) Epoxy stabilizers. (4) Salts of mineral acids, e.g., carbonates, sulfates, silicates, phosphates, and phosphates. (5) other organic compounds of metals and metalloids, e.g., alcoholates and mercaptides. Heat stabilizers are used nearly exclusively with vinyl resins. 

Epoxy compounds. Epoxy compounds function both as plasticizers and stabilizers in flexible and semirigid PVC. As stabilizers, epoxies react with liberated HCl. In addition, they react with the polymer chain at labile-chlorine sites—either directly or catalytically by increasing the reactivity of the labile-chlorine site with metal salt stabilizers. Most epoxy stabilizers are derived from unsaturated fatty oils and fatty acid esters. Epoxidized soybean and linseed oils and epoxy tallate are commonly used products. Epoxy tallate also increases light stability. Epoxy compovmds can be formulated with metallic liquid stearates and, thus, can be sold to compounders as a one-package system if a constant ratio of stabilizer-to-epoxy is acceptable. However, since these epoxy compounds are also plasticizers, the balance of the formulation must be adjusted for this effect. 

Epoxy ester. Epoxy ester plasticizers have limited compatibility with PVC. Therefore, they are used at low levels. Epoxidized soybean oil (ESO), the most widely used epoxy plasticizer, is also used as a secondary heat stabilizer. As a plasticizer, it provides excellent resistance to extraction by soapy water and low migration into adjoining materials that tend to absorb plasticizers. Other epoxy plasticizers include epoxidized linseed oil and epoxidized tall oils. Tall oils are prepared from tall oil fatty acids and Cs-Cs alcohols. 

Plastoflex, Epoxy-based stabilizers/plasticizer, Akzo Nobel Chemicals Inc. 

Description Used as stabilizing plasticizers and pigment dispersing agents for PVC alkyl epoxy stearate for low viscosity and low temperature performance ... 

The authors have established that alicyclic epojqr compounds are effective stabilizers of the polymer, in certain cases surpassing epoxided soy bean oil. Analogous stabilizer-plasticizers of polyvinyl chloride, representing epoxyhexahydrophthalates of bulyl, hexyl, iso-octyl, and certain other aliphatic alcohols, were described in [254] epoxided esters of 3,4-epoxycyclohexane-1,1-dimethanol and their alkyl-substituted derivatives [263], as well as 3,4-epoxy-l (or 6)-cyclohe g lmethyl esters of... 

Other materials that are often referred to as secondary plasticizers iaclude materials such as epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELO) and similar materials. These can act as lubricants but also as secondary stabilizers to PVC due to thein epoxy content which can remove HCl from the degrading polymer. 

Dimensional stability There is plastics with very good dimensional stability, and they are suitable where some age and environmental dimensional changes are permissible. These materials include polyphenylene oxide, polysulfone, phenoxy, mineral-filled phenolic, diallyl phthalate, epoxy, rigid vinyl, styrene, and various RPs. Such products will gain from an after-bake for dimensional stabilization. Glass fillers will improve the dimensional stability of all plastics. 

Several classes of polymers including epoxies have been developed from 2-phenyl-l,l,l,3,3,3-hexafluoropropan-2-ol and its derivatives.1 Fluorinated epoxy resins are the key intermediates for the new types ofpractical organic coatings and plastics, which have fluorocarbon properties and convenient characteristics such as hydrophobicity, oleophobicity, light stability, low friction, and, in some cases, possibly high thermal stability. 

Bisphenol A (BPA) (Figure 14.1a) is a starting substance utilized in the manufacture of most types of epoxy resins, which are then crosslinked and used to coat food cans. Another application of BPA is in the manufacture of plastic materials, in particular polycarbonates. BPA serves also as an antioxidant or stabilizing material for many types of plastics, e.g., polyvinyl chloride (PVC). 

Akutin (52) performed an exhaustive study on the influence of processing conditions and the nitrile rubber/poly(vinyl chloride) ratio on the mechanical characteristic of the product. The experiments were carried out in a Brabender Plastograph at 160-180° C and rotor speed of 10-50 rpm. The polyfvinyl chloride) molecular weight was 83500. A resin with an epoxy group content of 20.75% was added to the blend as plasticizer and stabilizer. Figure 29 shows that the... 

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