Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1998-09-25
2000-06-20
Sellers, Robert E.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523414, 528111, C08K 320, C08L 6302, C08L 6304
Patent
active
060778849
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns epoxy-amine adducts for use as emulsifiers for epoxy resins; epoxy resin dispersions on an aqueous basis using said emulsifiers and a process for their production.
2. Description of the Related Art
It is known to produce synthetic resins by emulsion polymerization and to produce stable aqueous dispersions of these resins in that one stabilizes the resin in the aqueous phase by the addition of suitable dispersing agents or by incorporated hydrophilic groups. In the case of condensates such as epoxy resins, which are difficult to produce by emulsion condensation, one must resort however to other processes. One of the most frequently used processes is the dispersion of a condensation reaction produced polyglycidyl ether based upon multifunctional (i.e., polyhydric) alcohols, phenols, hydration products of these phenols and/or of novolac and the like, in the aqueous phase with use of one or more suitable dispersing agents or, as the case may be, emulsifiers. Such epoxy resin dispersions are generally quite unstable and tend after a short period of time to precipitation of the binder, in particular at temperatures above 25.degree. C. The resulting epoxy resin dispersions exhibit as a rule particle sizes of more than 1 .mu.m thus tend, after several weeks or, as the case may be, several months in storage, to coalesce, to increase in particle size, and therewith to a deterioration of the film forming properties.
Several of these epoxy resin dispersions can, for reduction of viscosity and increasing dispersion stability, also have reactive thinners added thereto during their production. These are however, because of their toxic properties and because of generally high vapor pressure, undesirable in view of their workplace hygienic properties. Besides this, the chemical properties of the hardened epoxy resin films are often negatively influenced by these reactive thinners. Conventionally available epoxy resin dispersions further contain solvents, benzyl alcohol and glycols or glycol ethers and the like, which are also undesirable.
Water soluble and aqueous based epoxy resin systems assumed increasing importance due to the above discussed disadvantages and due to environmental concern discussions and corresponding changes in the state of the law in Germany and Europe.
In BE-OS 4310198 it is for example described, that special non-ionic emulsifiers, which are polyol-epoxy addition products of (A) an aliphatic diol with an average molar mass of 200 to 20000 g/Mol and of (B) an epoxy compound with at least two epoxy groups per molecule and an epoxy equivalent weight of 100 to 2000 g/Mol and an equivalent ratio of the OH-groups to the epoxy groups of 3:3.5 to 1:10 and wherein the epoxy equivalent weight of the addition product lies between 150 g/Mol and at least 8000 g/Mol, are particularly suitable for use in aqueous soluble epoxy fluid resin systems. Said aliphatic polyol (A) are polyether polyols (poly alkylene glycols), the epoxy compounds (B) are polyglycidyl ethers on the basis of di-valent alcohols or of novolac resins, with bisphenol A being particularly preferred. The above described emulsifiers are produced by the condensation of polyether polyols (A) with the epoxy compound (B) in the presence of suitable catalysts.
By mixing the so obtained emulsifiers with epoxy-fluid resins on the basis of bisphenol A- and bisphenol F-glycidyl ethers on obtains a self emulsifying fluid resin system, which would polymerize with aqueous soluble amine resins, for example polyamines and polyoxyalkylene di- and poly-amines with molecular weights of 100 to 2000 (JEFFAMINE.RTM., Texaco Corporation.) to films with good properties, which find use above all as protective coatings for mineral primers or undersurfaces.
In DE-OS4309639 aqueous based epoxy resin dispersions are described, which contain:
(A-1) an epoxy resin, which is a condensation product which is comprised of: epoxy groups per molecule and an epoxy equivalent weight of 100 to 2000, r
REFERENCES:
patent: 4769438 (1988-09-01), Zimmerman et al.
patent: 5565505 (1996-10-01), Papalos et al.
patent: 5604269 (1997-02-01), Papalos et al.
patent: 5874490 (1999-02-01), Arora et al.
Hess Michael
Hiller Michael
Schneider Horst
Sellers Robert E.
Sika Chemie GmbH
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