Phenoxy adhesives

This type of adhesive is generally useful in the temperature range where the material is either leathery or mbbery, ie, between the glass-transition temperature and the melt temperature. Hot-melt adhesives are based on thermoplastic polymers that may be compounded or uncompounded ethylene—vinyl acetate copolymers, paraffin waxes, polypropylene, phenoxy resins, styrene—butadiene copolymers, ethylene—ethyl acrylate copolymers, and low, and low density polypropylene are used in the compounded state polyesters, polyamides, and polyurethanes are used in the mosdy uncompounded state. 

Adhesives. High concentration (>10%) solutions of poly(ethylene oxide) exhibit wet tack properties that are used in several adhesive appHcations. The tackiness disappears when the polymer dries and this property can be successfully utilized in appHcations that require adhesion only in moist conditions. PEO is also known to form solution complexes with several phenoHc and phenoxy resins. Solution blends of PEO and phenoxy resins are known to exhibit synergistic effects, leading to high adhesion strength on aluminum surfaces. Adhesive formulations are available from the manufacturers. 

These differences in film morphology were also reflected as differences in film formation conditions, film adhesion, and in electrochemical properties. The pyrazoline beads readily formed films from solvents such as benzene. For the phenoxy TTF system, however, only CH2Cl2 was effective in forming films. In general, the TTF cross-linked polymers were found to be less adherent to the metallized substrates than the pyrazoline cross-linked polymers. Electro-chemically, it was found that the pyrazoline films showed complete activity after one potential sweep. The TTF polymer films, on the other hand, required from 5 to 20 cycles to reach full electrochemical activity as evidenced by a constant voltammogram with cycling. Furthermore, it was observed that the TTF polymer films were much less electroactive than the pyrazoline materials as shown by optical densities and total coulombs passed which were several times less for the TTF systems. 

Phenoxy resins may be extruded, injection-molded, and blow-molded to produce pipe, sporting goods, containers, and appliance housings. Since phenoxy resins are soluble in methyl ethyl ketone, they have been used as adhesives and cross-linkable protective coatings. 

The highest-MW DGEBA epoxy resins are termed phenoxy resins. They are highly linear molecules that are used primarily as thermoplastic coating resins. However, they can be blended with lower-MW epoxy resins for the improvement of specific properties such as flexibility, impact and fatigue resistance, and thermal cycling. Phenoxy resins are sometimes used alone as a thermoplastic hot melt adhesive generally in film form. 

Epoxy adhesives can be manufactured into a film form. This is most conveniently done with solid epoxy resins in solution. Epoxy film adhesives can be thermoplastic (e.g., linear ultrahigh molecular weight phenoxy resin) hot melts, but more commonly they are formulated, thermosetting materials. 

Solid epoxy adhesive formulations can be processed to either a thermoplastic or a thermoset state. Solid epoxy resins of exceptionally high molecular weight (e.g., phenoxy) can be used without any degree of cure as a hot-melt type of adhesive. However, fully crosslinked, thermoset systems are generally employed in structural applications. 

The phenoxy resins can also be plasticized with many of the common plasticizers and still maintain a high percentage of strength, while the bonding temperature is substantially reduced. An effective hot-melt adhesive is one in which polyvinyl ether is blended into the phenoxy resin. 

They are exceptionally useful in primer plastic applications where drying speed, compatibility with various kinds of topcoats, and high adhesive strength is required. Phenoxies are used in automotive and marine primers as well as in heavy-duty maintenance primers. Important use is as a vehicle for coating formulations. 

The ductility of phenoxy resins resembles that of metals. They are transparent and also characterized by low mold shrinkage, good dimensional stability, and moderately good resistance to temperature and corrosion. Phenoxy resins are soluble in methyl ethyl ketone and have been used for coatings and adhesives. A typical injection-molded specimen has a tensile strength of 9000 psi, heat distortion point 86.6C at 264 psi load, and d 1.18. 

The commercially available phenoxy resin has Mw around 50,000 and little epoxy functionality. The phenoxy polymer is then classified as a polyol or a po-ly(hydroxy ether) [3]. Typical applications for the phenoxy resin are as hot-melt adhesives, coatings for beverage cans, and toughening agents for various epoxy resin formulations. The viscoelastic properties of phenoxy resins have been studied by Alegria et al. [11-15]. The phenoxy polymer can be used as a reference in the viscoelastic study of DGEBA oligomer. 

Phenoxy Plastics 1962 H-M F F F F F Injection, blow and extrusion molding, coatings and adhesives Adhesives for pipebonding compounds, bottles... 

Uses Phenolic, adhesion promoter, chem. resist, aid for drum and pail coatings, latex and phenoxy polymers crosslinking agent for water-based polymers intended for low VQC applies. food pkg. adhesives, coatings, paper, closures with sealing gaskets for food containers Features Thermosetting compat. with various waterborne acrylic, epoxy, and phenoxy resins... 

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