Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-01-18
2003-11-11
Dawson, Robert (Department: 1712)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C405S259500, C523S401000, C523S466000, C523S467000
Reexamination Certificate
active
06645340
ABSTRACT:
FIELD OF INVENTION
The object of the present invention are curable two-component mortar compositions based on a curable epoxide resin, at least one reactive diluent for the epoxide resin, an amine curing agent and one or more inorganic fillers, as well as, optionally, curing catalysts, rheological aids, thixotropizing agents, fillers, dispersants, agents for controlling the reaction rate and wetting agents, the amine curing agent being kept separate from the curable epoxide resin and the reactive diluents in order to inhibit any reaction, as well as their use for fastening anchoring materials, such as tie bars in boreholes.
BACKGROUND INFORMATION AND PRIOR ART
Organic, curable, two-component mortar compositions based on curable epoxide resins and amine curing agents have long been known and are used as adhesives, lacquers, fillers for filling cracks and, for instance, for fastening anchoring means, such as tie bars, in boreholes, dowel holes and the like. When such mortar compositions are used especially at building sites in the open, difficulties arise because, on the one hand, it must be possible to handle the mortar composition well even at low temperatures and, on the other, the mortar composition must exhibit little creep at elevated temperatures. At the same time, however, the composition must have a long processing duration and, nevertheless, must cure rapidly and completely, achieving high load values even at low temperatures and good dimensional stability at elevated temperatures of the cured composition. These partially contradictory property profiles cannot be achieved readily. For example, in order to achieve good handling properties at low temperatures, it is customary to provide conventional mortar compositions with a high proportion of components of low viscosity, a small proportion of fillers and coarse fillers; however, this is disadvantageous for keeping creep low under a load at elevated temperatures. On the other hand, a long processing time is achieved by a high proportion of components of low activity and of diluents, which are not reactive and do not cross link. However, this conflicts with a short curing time.
In the German patent application 198 32 669.6, which was not pre-published, a curable epoxide composition is already proposed, which contains polyepoxide, polyamine, polyacetoacetate and a metal compound, especially the compound of a metal cation, and optionally conventional components, such as fillers, diluents, curing catalysts, rheological aids, wetting agents, dyes and pigments and the like. In this connection, the polyacetoacetate, as a reactive diluent to reduce the high viscosity of the liquid polyepoxide, and the metal compound improve the reactivity with respect to the walls of the mineral borehole.
From the German patent application 198 32 668.8, which has also not been pre-published, a curable two-component mortar composition with curable organic and curable inorganic components and curing agents is described. The curing agents are kept separate from the respective curable component to inhibit reaction, but can be activated for application or use. This composition contains epoxide resin and finely divided cement as curable components and amines and alkali silicate as curing agents. These inorganic/organic mortar compositions require the presence of water for curing the cement, by means of which the latter is reacted completely. This can lead to corrosion, especially of the steel tie bars, if cracks occur or if water penetrates into the annular gap between the tie bar and the mortar.
OBJECT OF THE INVENTION
It is an object of the present invention to indicate a curable two-component mortar composition of the type indicated above, which has improved handling properties in comparison to those of conventional commercial systems, especially at low temperatures and during long processing times, as well as a short curing time, a low tendency to creep in the cured state at elevated temperatures, good dimensional stability at elevated temperatures and a high chemical resistance, as well as high load values at low temperatures (−5° C.) up to elevated temperatures (60° C.) and, in accordance with a preferred embodiment, develops a corrosion protection effect.
SUMMARY OF THE INVENTION
This objective is accomplished by the curable two-component mortar composition of claim 1. The dependent claims relate to preferred embodiments of this inventive object, as well as to the use of this mortar composition for fastening anchoring means in boreholes in natural as well as in artificial rock.
The invention accordingly relates to a curable, two-component mortar composition based on a curable epoxide resin, at least one reactive diluent for the epoxide resin, an amine curing agent and one or more inorganic fillers, as well as, optionally, curing catalysts, Theological aids, thixotropizing agents, stabilizers, dispersants, agents to control the reaction rate and wetting agents, the amine curing agents being kept separate from the curable epoxide resin and the reactive diluent in order to inhibit any reaction, wherein the mortar composition contains a cross-linking, reactive diluent having functional epoxy groups with an epoxy functionality of at least 2.
Surprisingly, it has turned out that, due to the use of a cross-linking reactive diluent, having functional epoxy groups and an epoxy functionality of at least 2, especially with an epoxy functionality of 2 to 3, which is achieved especially by mixing a difunctional with a trifunctional reactive diluent of this type, a mortar composition is obtained, which accomplishes the task addressed above in an outstanding manner in that, due to the presence of this cross-linking reactive diluent, the disadvantages of the diluents or solvents, used in conventional mortar compositions of this type, such as, especially, monoglycidyl ether compounds, benzyl alcohol or the like, can be overcome and the viscosity, the required for good extrusion properties of the system and seating properties of the anchor, especially at low temperatures, can be adjusted selectively and, nevertheless, good curing of the mortar composition can be achieved even though processing times are sufficiently long. In the same way, a low tendency to creep under load, especially at elevated temperatures, can be achieved.
Cross-linking, reactive diluents having functional epoxy groups with an epoxy functionality are compounds, which have two epoxy groups, which react with the curing agent, and thus can bring about a cross-linking of the polymer chains.
Due to the use of the cross-linking reactive diluent with a functionality of at least 2, a degree of cross-linking, which is higher, and a reaction rate, which is high in comparison to previously used bifunctional or monofunctional reactive diluents, that is, reactive diluents with an epoxy functionality of less than 2, can be achieved at a lower viscosity of the mortar composition after the components are mixed and brought into the borehole, and with a higher degree of cross-linking and a high reaction rate.
The polymer, resulting therefrom, has an advantageous cross-linked structure. At the same time, the composition contains a lesser proportion of extractable portions and therefore tends less to form cracks, to shrink and to creep at elevated temperatures under load. Moreover, a higher dimensional stability at elevated temperatures, an improved toughness and, with that, high load values can be achieved even at elevated temperatures. Due to the use of this reactive diluent pursuant to the invention, sufficiently short curing times are achieved even at temperatures as low as −5° C.
Pursuant to a preferred embodiment, the mortar composition contains, as reactive diluent, at least one diglycidyl ether or a mixture of at least one diglycidyl ether and at least one triglycidyl ether for adjusting the epoxy functionality to an average value of at least 2. Especially preferred is the use of glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether and/or trimethylolpropane triglycidyl ether or
Dierker Sascha
Gienau Roland
Krauter Mechthild
Aylward D.
Dawson Robert
Hilti Aktiengesellschaft
Sidley Austin Brown & Wood LLP
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