Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-03-26
1998-06-23
Szekely, Peter A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523131, 524284, 524300, 524315, 524318, 524321, 524322, 524378, 524394, 524385, C09K 1720, C08K 5101, C08K 5103
Patent
active
057706395
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improvement in and extension of the teaching described in earlier German patent application P 43 24 474.2 for the surface stabilization of sand and/or soil, hereinafter generally referred to as soil. This earlier application describes a modification to the process known per se of achieving at least temporary stabilization by application and introduction of aqueous polymer dispersions to and into surface layers of soil. The water in the impregnating composition introduced dries in a comparatively short time and the polymer phase remaining behind solidifies the structure, for example the granular structure, of the impregnated soil without unduly affecting the permeability of these layers to water. Surface stabilization such as this is not confined to soil in the narrower sense. The corresponding stabilization of other surface zones which have to be protected, for example, against wind erosion falls within the scope of the teaching according to the invention. Examples of such surface zones include dumps and/or spoil banks with or without application of a covering of top soil or other protective layers.
2. Discussion of Related Art
Development and practice have been concerned for decades with the concept--on which the present invention is also based--of applying synthetic polymers which cause particulate solids to adhere to one another to the surfaces to be stabilized in the form of aqueous dispersions or emulsions and leaving them to dry thereon. Aqueous polyvinyl acetate dispersions, hereinafter also referred to as PVAc dispersions, are of particular significance in this regard, cf. A. Kullmann et al. in Arch. Acker-Pflanzenbau Bodenkd., 22(11), 713-19. Besides polyvinyl acetate, butadiene/styrene latex, a urea/formaldehyde polymer and a bitumen emulsion are described as useful binders. The corresponding stabilization of dune sand against the effects of rain is the subject of an article by D. Gabriels et al. (Univ. Ghent, Belgium) in Soil Sci, 118(5), 332-8. In this publication, too, a binder system based on polyvinyl acetate is included among the preferred binders. U.S. Pat. Nos. 4,072,020, 3,887,506, HU 11 654 and ZA 7501787 are mentioned as examples of the other works being carried out worldwide.
The list of requirements or functions to be fulfilled by corresponding stabilization of the earth's surface can be extremely diverse. Without any claim to completeness, some of the properties required in practice are mentioned in the following: the material should be resistant at least to pedestrian traffic, it should not be affected by the particular temperatures prevailing, atmospheric humidity or rain (for the period envisaged) and should also be resistant to high wind speeds. The material to be applied should be non-inflammable and should not represent a fire or explosion risk either in storage or during and after its application. Its transport and application should not entail any exceptional protective measures or the wearing of protective clothing. The cured polymer impregnation should not have any toxic effect on germinating plants, on growing plants or on animals and should be colorless or transparent. Taking these and other requirements into account, the present state of the art may be summarized as follows: absence of plasticizers, however, the cohesion of the soil layers impregnated with PVAc homopolymer dispersions is so brittle that key application requirements are not satisfied. capable of flow under normal conditions. In practice, dibutyl phthalate has proved to be a particularly effective plasticizer. Correspondingly plasticized PVAc homopolymers provide for firm cohesion although the plasticizer is non-degradable. maleate) provide for firm cohesion but are also non-degradable.
The teaching of earlier German patent application P 43 24 474.2 cited at the beginning addresses the problem of providing PVAc homopolymer dispersions for the described application with plasticizers which, on the one hand, meet the diverse
REFERENCES:
patent: 3887506 (1975-06-01), Hewitt
patent: 4072020 (1978-02-01), Bishop
patent: 4107112 (1978-08-01), Loitta, Jr. et al.
Arch. AckerPflanzenbau bodenkd., 22(11), 713-19.
(Univ. Ghent, Belgium) in Soil Sci, 118(5), 332-8.
"Der quantitative mikrobiolgische Abbau von Lackkunstharzen und Polymerdispersionen (The Quantitative Microbiological degradation of Paint-Grad Resins and Polymer Dispersions)", Farbe + Lack, vol. 98, Jul. 1992, 505-8.
Hoeltgen Christiane
Ritter Wolfgang
von Tapavicza Stephan
Grandmaison Real J.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Szekely Peter A.
Szoke Ernest G.
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