Adhesives, epoxy resin

Epoxy Resins. The chemistry of epoxy resin adhesives is quite varied. However, the most widely used is that formed from the reaction of 4,4 -isopropyhdene diphenol (bisphenol A) [80-05-7] and epichlorohydrin [106-89-8] C H CIO. This epoxy resin is more commonly known as... 

Pentaerythritol in rosin ester form is used in hot-melt adhesive formulations, especially ethylene—vinyl acetate (EVA) copolymers, as a tackifier. Polyethers of pentaerythritol or trim ethyl ol eth an e are also used in EVA and polyurethane adhesives, which exhibit excellent bond strength and water resistance. The adhesives maybe available as EVA melts or dispersions (90,91) or as thixotropic, one-package, curable polyurethanes (92). Pentaerythritol spko ortho esters have been used in epoxy resin adhesives (93). The EVA adhesives are especially suitable for cellulose (paper, etc) bonding. 

Antimonious acid H3Sb03 and its salts are less well characterized but a few meta-antimonites and polyantimonites are known, e.g. NaSb02, NaSb305.H20 and Na2Sb407. The oxide itself finds extensive use as a flame retardant in fabrics, paper, paints, plastics, epoxy resins, adhesives and rubbers. The scale of industrial use can be gauged from the US statistics which indicate an annual consumption of Sb203 of some 10000 tonnes in that country. 

Aromatic amines formed from the reduction of azo colorants in toy products were analysed by means of HPLC-PDA [703], Drews et al. [704] have applied HPLC/ELSD and UV/VIS detection for quantifying SFE and ASE extracts of butyl stearate finish on various commercial yarns. From the calibrated ELSD response the total extract (finish and polyester trimer) is obtained and from the UV/VIS response the trimer only. Representative SFE-ELSD/UV finish analysis data compare satisfactorily to their corresponding SFE gravimetric weight recovery results. GC, HPLC and SEC are also used for characterisation of low-MW compounds (e.g. curing agents, plasticisers, by-products of curing reactions) in epoxy resin adhesives. 

FIGURE 4.9 Curing of two-part epoxy resin adhesives. 

Epoxy Resin Adhesives from Kraft Lignin... 

Epoxy resin adhesives from lignin were reported by Tai et al. (19,20) in 1967. Satisfactory gluability was found. The solubility in organic solvents, however, was found to be poor. In essence, the phenolic hydroxyl groups of kraft lignin were glycidylated directly. 

We have also made an attempt to prepare lignin-epoxy resin adhesives (21). However, in order to improve its reactivity, kraft lignin was first phenolated with bisphenol-A. For phenolation, a small amount of aqueous hydrochloric acid or BF3-ethyl etherate was used as catalyst, and thus two kinds of glycidylation methods were adopted (21). The phenolation with bisphenol-A was found to enhance the solubility of the lignin derivative. In fact, the lignin-epoxy resins obtained were found to be completely soluble in certain organic solvents, including acetone. 

The gluability of the lignin-epoxy resin adhesives was found to be improved by the addition of calcium carbonate (50% by weight) to the liquid resin. This must be attributed to the nature of the weak alkali in calcium carbonate as a cure accelerator, and to the reinforcement effect of fillers. Since wood surfaces are acidic, the addition of alkaline fillers effectively alters the pH of the glue line. 

This review will first present the metal/epoxy resin adhesive system and discuss how the presence of metal oxides influences adhesion secondly, present the reasons why these systems exhibit very good adhesion strength under dry conditions and why this adhesion strength is greatly reduced in the presence of water thirdly, examine possible methods of increasing their durability in wet environments and finally, discuss some of the spectroscopic techniques that are currently being used to aid in the advancement of metal/polymer adhesion technology. 

MW 92.53 CAS [106-89-8] used to make epoxy resins, adhesives, surfactants, and plasticizers, and also as a solvent for gums, resins, and paints colorless liquid chloroform-like odor boils at 116°C solidifies at-57°C vapor pressure 12 torr at 20°C density 1.18 g/mL at 20°C moderately soluble in water (6.6% at 20°C), soluble in most organic solvents moderately toxic, carcinogenic, and a strong irritant (Patnaik, 1992). 

Meath, A. R., Epoxy Resin Adhesives, Chapter 19 in Elandbook of Adhesives, 3d ed., I. Skeist, ed., van Nostrand Reinhold, New York, 1990. 

Bell, J. P., et al., Amine Cured Epoxy Resins Adhesion Loss due to Reaction with Air, Journal of Applied Polymer Science, vol. 21,1977, pp. 1095-1102. 

Several methods can be used by the formulator to improve the flexibility of room temperature curing epoxy resin adhesive formulations ... 

Hopper, F. C., and Naps, M., Epoxy Resin Adhesive Compositions, Their Preparation, and Tape Containing the Same, U.S. Patent 2,915,490, 1959. 

Savia, Epoxy Resin Adhesives, and Politi, Structural Adhesives in the Aerospace Industry. ... 

A waste is an ignitable hazardous waste if it has a flash point of less than 60 °C, readily causes fires and burns so vigorously as to create a hazard. A simple method of determining the flash point of a waste is to review the material safety data sheet, which can be obtained from the manufacturer or distributor of the material. Naphtha, lacquer thinner, epoxy resins, adhesives, and oil based paints are all examples of ignitable hazardous wastes. 

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