Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-07-26
2001-09-18
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C405S259500, C523S466000, C524S849000
Reexamination Certificate
active
06291555
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a highly viscous chemical anchoring adhesive useful in industrial or commercial construction applications such as bridges, airports, highways, skyscrapers, stadiums and tunnels. The chemical anchoring adhesive can be formed to a desired shape and/or cut to a desired length, before being sent to the job site or at the job site. Because of its high viscosity, the anchoring adhesive can be injected into a borehole which is upside down and vertical, or horizontal, or oriented at any angle, and will not spill or flow out of the borehole.
BACKGROUND OF THE INVENTION
Chemical anchoring adhesives are known which are composed of two or more components that react together and cure when mixed. U.S. Pat. No. 5,730,557, issued to Skupian et al., discloses a mortar mixture capsule unit for chemical attachment of anchors in boreholes. The capsule houses a filler material, and a chemical binder system contained in smaller capsules within the filler material. The cartridge is inserted into a borehole, and a driving tool is used to insert an anchor. The driving tool imparts motion to the anchor, which ruptures both the housing capsule and the smaller capsules contained within it, causing the chemical binder system to interact and mix with the filler. The interaction and mixing causes reaction and curing of the binder system/filler mixture, thereby securing the anchor within the borehole. A similar adhesive is sold by Hilti AG under the trade name “HVU”.
U.S. Pat. No. 5,731,366, issued to Moench et al., discloses a chemical plugging compound based on a free-radically polymerizable resin and a free-radical initiator spatially separated from the resin. The spatial separation can be effected by encapsulating the initiator in glass, gelatin or cellulose capsules. The plugging compound is described as being self-supporting and storage stable.
This and other prior art chemical anchoring adhesives have certain disadvantages. One disadvantage is that one or both components are fluid, and must be wrapped, encapsulated or otherwise enclosed in a package prior to use. Thus, it is not easy to vary the amount of adhesive used in a borehole, or the size of the housing capsule, while at the job site. Put another way, oversized and undersized boreholes will receive the same amount of predetermined, pre-packaged adhesive as boreholes of standard size.
Another disadvantage is that the fluid adhesives may flow or spill from the boreholes during use, particularly after the package is ruptured by the anchor being driven. This problem is especially acute when the borehole is upside down and vertical, but also exists when the borehole is horizontal, or at an angle between horizontal and upside down vertical. Even when the adhesive is not completely fluid, the prior art cartridges are typically not self-retentive, i.e., the cartridges will fall from overhead boreholes.
Another disadvantage is that the two components, binder and filler, must be completely segregated prior to use, to prevent premature interaction and reaction. The encapsulation techniques used to accomplish this require some precision and expense. Also, there is no assurance that the smaller capsules used to contain the binder will remain evenly dispersed among the filler until the adhesive capsule is used. Uneven dispersion of the binder and filler can lead to uneven or inadequate adhesion of the anchor.
Cartridge adhesives are another type of prior art adhesive. Cartridge adhesives include two separate parts which are simultaneously injected into a borehole using a two-barrel caulking gun which brings the two parts together at the point of injection, whereupon they react upon entering the borehole. Disadvantages of cartridge adhesives include excessive packaging waste, excessive adhesive waste due to unmixed, unused material remaining in the caulking barrels, and insufficient viscosity, which permits the material to run out of vertical overhead boreholes, and to sag in horizontal boreholes.
SUMMARY OF THE INVENTION
The present invention is directed to an anchoring adhesive composition including two parts, both of which have a viscous, solid, putty-like consistency. The two parts can be joined side-by-side in a rope or other elongated configuration, without encapsulating one relative to the other, and without causing significant premature reaction between the two parts. Because of their high viscosity, the two-part adhesive can be employed in an upside down vertical borehole, a horizontal borehole, or a borehole having an angle between horizontal and upside down vertical, and will not spill or flow from the borehole or sag within the borehole.
The first part of the adhesive comprises a resin. The first part has a viscosity between about 5 million and about 50 million centipoise, measured at 25° C. using a Brookfield Viscometer, Model DV-3, made by Brookfield Engineering Co. This viscosity range assures that the adhesive may be formed, shaped, and/or cut with a knife, but will not flow. In one embodiment, the first part of the adhesive includes an epoxy resin (e.g., a liquid epoxy resin), and at least one particulate filler, in proportions required to achieve the desired viscosity.
The second part of the adhesive comprises a curing agent. The second part has a viscosity between about 5 million and about 50 million centipoise, measured using the same test equipment. The viscosity of the second part is not more than 30% higher or 30% lower than the viscosity of the first part. In the one embodiment, the second part of the adhesive includes a curing compound, a curing accelerator, and at least one particulate filler, in proportions required to achieve the desired viscosity.
The first and second parts can be extruded, pressed, or otherwise joined together in the form of a rope having a cylindrical, rectangular, square, triangular, or other suitable shape. The rope may have any suitable cross-sectional diameter, and any suitable length. The rope may be wrapped around its circumference with a suitable wrapper of plastic film, metal foil, paper, or the like. The first and second parts are directly joined along at least one interface extending the length of the rope. By “directly joined” it is meant that no film, capsule or other barrier is interposed between the two parts.
The rope of anchoring adhesive may be cut or sheared to any size, depending on the depth of the borehole. In one embodiment, the proper amount of adhesive can be measured by the depth of the borehole, i.e., by inserting a rope end into the borehole as far as possible, and cutting the rope at the top of the borehole. If the boreholes vary in depth, the adhesive may be cut or sheared to varying lengths on the job site, to provide the optimum amount of adhesive for each borehole. Because the two parts are extruded side-by-side, the amount of each part relative to the other is substantially consistent along the length of the rope. The only direct contact between the two parts prior to use is along a single interface. Premature reaction between them is thereby minimized without requiring encapsulation of one part relative to the other.
With the foregoing in mind, it is a feature and advantage of the invention to provide a highly viscous, two-part anchoring adhesive which can be used in a downward or horizontally-opening borehole without spilling from the borehole.
It is also a feature and advantage of the invention to provide a two-part anchoring adhesive composition having a consistent composition along its axial length, which provides consistent high-quality anchoring force in heavy construction applications, and which can be cut to any desired length on the job site, or before reaching the job site.
The foregoing and other features and advantages will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings and examples. The detailed description, drawings and examples are illustrative rather than limiting, the scope of the invention being
Ernst Richard J.
Hackl Cyndie S.
Presnell Eldridge
Surjan James E.
Timmerman Mark S.
Aylward D.
Breh Donald J.
Cove Mark W.
Dawson Robert
Illinois Tool Works Inc
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