- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant/s: Hilti Aktiengesellschaft Actual Inventor/s: Memet-Emin Kumru and Sandra Maiershofer and Arne Reinheimer and Armin Pfeil Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: METHOD FOR IMPROVING THE ADHESION OF CHEMICAL TWO-COMPONENT MORTAR COMPOSITIONS TO THE SURFACE OF MOIST BOREHOLES IN A MINERAL SUBSTRATE AND THE SOLUTION FOR IMPLEMENTING THE METHOD The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 64770AUP00 METHOD FOR IMPROVING THE ADHESION OF CHEMICAL TWO-COMPONENT MORTAR COMPOSITIONS TO THE SURFACE OF MOIST BOREHOLES IN A MINERAL SUBSTRATE AND THE SOLUTION FOR IMPLEMENTING THE METHOD BACKGROUND OF THE INVENTION Field of the Invention 5 The present invention relates to a method for improving the adhesion of chemical two-component mortar compositions with a resin component (A), which contains, as curable component, at least one free radical-curable, ethylenically unsaturated compound (a) and a curing agent component (B), which is disposed separately therefrom so as to inhibit reaction and contains 10 a curing agent for the resin of the resin component (A), to the surface of moist boreholes in a mineral substrate, such as concrete or natural stone, as well as a solution for implementing this method. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or 15 forms part of common general knowledge in the field. Description of the Prior Art For fastening component parts, such as threaded rod anchors, reinforcing bars, threaded sleeves and screws in boreholes, which are present la in a mineral substrate such as concrete, natural stone, plaster etc., especially when high load values of the immobilization are to be attained, chemical two-component mortar compositions are used, which comprise a resin component, which contains at least one free radical-curable, ethylenically 5 unsaturated compound and a curing component, which is disposed separately therefrom so as to inhibit reaction and contains a curing agent for the resin of the resin component. For the application, initially the boreholes for accommodating the component parts to be fastened are drilled with the appropriate dimensions in the mineral substrate. Subsequently, the drilling 10 dust must be removed from the boreholes, after which the resin component is mixed with the curing component, the chemical two-component mortar composition is transferred into the borehole and the component part, which is to be fastened, is then introduced into the borehole filled with mortar composition and adjusted. After the mortar composition has cured by the 15 reaction of the resin component with the curing agent, the component part is held firmly. The load values of the component parts fastened in this way and, with that, the carrying behavior depend on several parameters, which are divided in the literature into two classes as internal and external parameters. 20 External parameters include, among others, the nature of the cleaning of the 2 boreholes, the quality of the mineral substrate, for example, the concrete, the moisture content and temperature of the latter, as well as the way in which the borehole is produced. The internal parameters include the chemical composition of the 5 mortar composition and the manufacturing process for and the packaging of the mortar composition, which usually comprises two components, which are contained in separate containers, such as glass and the like. It has turned out that the way in which the borehole is cleaned and the moisture content of the mineral substrate are important parameters affecting 10 the carrying behavior of the chemical mortar composition. A very appreciable decrease in performance, which manifests itself in lower load values, occurs in moist boreholes and in boreholes, which have not been cleaned well to remove the drilling dust. To overcome these disadvantages, the prior art provides, on the one 15 hand, for an increased expenditure for cleaning the boreholes and, on the other, for taking care that the boreholes are not moist, as otherwise a decrease in load values is to be expected. 3 SUMMARY OF THE INVENTION It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. 5 In a preferred embodiment, the present invention provides a method, with which the adhesion of chemical, two-component mortar compositions of the type given above to the surface of boreholes, which are produced in a mineral substrate, such as concrete, natural stone or the like, and have not been cleaned well and/or are moist. 10 The method of the present invention comprises treating the surface of the moist boreholes in the mineral substrate with a methacryloxyalkyltrialkoxysilane, before the mortar composition, formed by mixing the resin component (A) with the curing agent component (B), is introduced. 15 Surprisingly, in this way, it is possible to improve the load values of the fastened component parts clearly, without having to clean or dry the boreholes in the mineral substrate in an expensive way, as is normally required for achieving adequately high load values. 4 The present invention accordingly relates to a method for improving the adhesion of chemical, two-component mortar compositions with a resin component (A), which, as curable component, contains at least one free radical-curable, ethylenically unsaturated compound (a), and a curing 5 component (B), which is disposed separately therefrom to inhibit reaction and contains a curing agent for the resin of the resin component (A), to the surface of moist the boreholes in mineral substrates, wherein, before the mortar composition is introduced into the moist boreholes, the surface of the latter is treated with a methacryloxyalkyltrialkoxys ilane. 10 In accordance with a preferred embodiment of the invention, the surface of the moist boreholes is treated with a methacryloxyalkyltrialkoxys i lane of the general Formula I: 0 Il 0 CC2 RiO,
(CH
2 ), RiO OR, in which 15 R, represents identical or different alkyl groups with I or 2 carbon atoms and n is a whole number with a value from 1 to 3. 5 In a particularly preferred manner, the surface of the moist boreholes, before the mortar composition is introduced, is treated with methacryloxymethyltri-methoxys ilane, methacryloxyethyltrimethoxys ilane, methacryloxypropyl ltri methoxy-s i lane, methacryloxymethyltriethoxys i lane, 5 methacryloxyethyltriethoxysi lane, meth-acryloxypropyltriethoxys i lane or mixture thereof. For the inventive method, the methacryloxyalkyltrialkoxysilane can be used either in pure form or also in the form of a solution, preferably in a (meth)acrylate ester as solvent. Preferably, a (meth)acrylate ester, selected 10 from the group comprising hydroxypropyl (meth)acrylate, 1,2 dihydroxybutane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 2-ethylhexyl (meth)acrylate, phenylethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl triglycol (meth)acrylate, N,N- dimethylaminoethyl (meth)acrylate, N,N 15 dimethylaminomethyl (meth)acrylate, 1,4-dihydroxybutane di(meth)acrylate, acetoacetoxyethyl (meth)acrylate, 1,2 dihydroxyethane di(meth)acrylate, isobornyl (meth)acrylate, diethylene glycol di(meth)acrylate, methoxy polyethylene glycol mo no(meth)acrylate, trimethyl cyclohexyl (meth)acrylate, 2-hydroxyethyl 20 (meth)acrylate, dicyclopentenyl hydroxyethyl (meth)acrylate and/or 6 tricyclopentadienyl di(meth)acrylate, bisphenol A (meth)acrylate, novolak epoxy di(meth)acrylate, di-((meth)acryloyl maleoyl) tricyclo 2.6 5.2.1.0. -decane, dicyclopentenyl hydroxyethyl crotonate, 3 (meth)acryloyl hydroxoxymethyl tricylo-5.2.1 .0.26 -decane, 3-methyl 5 cyclopentadienyl (meth)acrylate, isobornyl (meth)acrylate and/or decalyl 2-(meth)acrylate is used as solvent. According to the invention, the surface of the moist boreholes is treated by being brushed or sprayed with the methacryloxyalkyltrialkoxysilane or a solution thereof. For the inventive method, it is merely necessary to blow out 10 the borehole twice with a bicycle pump-like spraying device of the type customary for the use of chemical mortar compositions. Subsequently, the borehole is brushed or sprayed with the methacryloxyalkyltrialkoxysilane in pure or diluted form. If this cleaning is employed, which requires less effort than the cleaning in the normal case, the load values obtained with dry concrete 15 are similar to those obtained with heavy cleaning, for which the boreholes are cleaned by vacuuming them repeatedly or by using a brush. With that, the work involved in preparing the boreholes in the mineral substrate can be reduced clearly. Moreover, it has turned out that the load values obtained with the 20 inventive method when the borehole is moist, surprisingly are not as bad. 7 This improvement in the load values in the case of poorly cleaned and/or moist boreholes is all the more surprising because primers in the classical sense normally require the treatment of a clean dry and fat-free substrate, as well as the longer drying times. 5 The inventive method accordingly makes it possible to decrease the cost of cleaning and, with that, of preparing the boreholes considerably and, at the same time, to improve the robustness of the system, that is, to achieve uniformly high load values even if the surfaces of the boreholes are moist. The present invention further relates to a solution for carrying out the 10 inventive method, which is characterized by a 50 to 100% and preferably 60 to 70% solution of the methacryloxyalkyltrialkoxysilane in a (meth)acrylate ester selected from the group comprising hydroxypropyl (meth)acrylate, 1,2-dihydroxybutane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 2-ethylhexyl (meth)-acrylate, phenylethyl 15 (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethyl triglycol (meth)acrylate, N,N-dimethylamino-ethyl (meth)acrylate, N,N dimethyl-aminomethyl (meth)acrylate, 1,4-dihydroxybutane di(meth)acrylate, aceto-acetoxyethyl (meth)acrylate, 1,2 dihydroxyethane di(meth)acrylate, iso-bornyl (meth)acrylate, 20 diethylene glycol di(meth)acrylate, methoxypoly-ethylene glycol 8 mono(meth)acrylate, trimethylcyclohexyl (meth)acrylate, 2-hydroxy ethyl (meth)acrylate, dicyclopentenyl hydroxyethyl (meth)acrylate and/or tricyclopentadienyl di(meth)acrylate, bisphenol A (meth)acrylate, novolak epoxy di(meth)acrylate, di 5 [(meth)acryloylmaleoyl]-tricyclo-5.2.1 .0.
2
,
6 -decane, dicyclopentenylhydroxyethyl crotonate, 3-(meth)acryloyl hydroxymethyltricylo-5.2.1 .0.
2 .6-decane 3-(methyl)-clopentadienyl (meth)-acrylate, isobornyl (meth)acrylate and/or decalyl 2-(me th)acrylate. 10 Preferably, the solution contains a methacryloxyalkyltrialkoxy silane of the above general Formula I. In a particularly preferred manner, the solution, as methacryloxyalkyltrialkoxysilane, contains methacryloxymethyltrimethoxy-silane, 15 methacryloxyethyltrimethoxysilane, methacryloxypropyltrimethoxy silane, methacryloxymethyltriethoxysilane, methacryloxyethyltriethoxy- silane, methacryloxypropyltriethoxysilane or mixtures thereof. The following examples are intended to explain the invention 20 further. 9 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Example I To begin with, the resin component (A) of a chemical two 5 component mortar composition is prepared by homogenizing 39.3 g of the UMA resin, which has the composition given in the following Table 1, 37.2 g of a quartz sand (for example, F32), 20.5 g of an aluminate cement and 3 g of a hydrophobic, pyrogenic silica in a Dissolver under vacuum until a pasty composition, free of air 10 bubbles, is obtained. The resin component (A), so obtained, is filled into a cartridge. Table I UMA Resin Weight % Urethane methacrylate oligomer, difunctional 32.61 1,4-Dihydroxybutane dimethacrylate 32.62 Hydroxypropyl methacrylate 32.62 p-Toluidine (accelerator) 1.70 Inhibitor (Tempol)*) 0.45 Total 100 *) Tempol = 4-hydroxy-2,2,6,6-tetramethyl piperidinooxyl 10 As curing agent component (B), a conventional commercial curing agent component, consisting of an aqueous suspension of benzyl peroxide, containing finely ground quartz and pyrogenic silica with a total filler content of 60% by weight, 7.5% by weight of 5 benzoyl peroxide, water constituting the remainder, is used. This composition, like the resin component (A), is filled into a cartridge. For the intended use, the resin component and the curing agent component are pressed out of the cartridges and passed through a static mixer, as a result of which the reaction of these components 10 commences with curing of the reaction resin and of the aluminate cement. The reacting composition is injected into a borehole, whereupon the part, which is to be fastened, is introduced and adjusted. Example 2 15 Determination of the Load Values For determining the load values of the cured composition, a high strength, M12 threaded rod anchor is used, which is doweled into a borehole with a diameter of 14 mm and a depth of 110 mm with the given chemical two-component mortar composition. The average failure load is 11 determined by pulling out the threaded rod anchor centrally with a narrow support. In each case, five threaded rod anchors are doweled in and the load values are determined after a curing time of 24 hours at room temperature. The load values determined here are listed in the following Table 2. 5 The boreholes, used for this investigation, were pre-treated in the following way: 1. Dry concrete and concrete saturated with water: To begin with, the borehole is drilled with a diameter of 14 mm and a depth of 110 mm. It is cleaned only by blowing it out twice with the "Putzi" pump. Subsequently, the borehole is sprayed with methacryloxymethyltri-methoxysilane, the mortar composition, formed by mixing the resin component (A) with the curing agent component (B), is pressed from the cartridges by the static mixer into the borehole, the threaded rod anchor is set and adjusted and the mortar composition is allowed to cure for 24 hours at room temperature. 2. Dry concrete and concrete saturated with water: To begin with, the borehole is drilled with a diameter of 14 mm and a depth of 110 mm. The borehole is cleaned by vacuuming, brushed out three times and vacuumed once again. Subsequently, the mortar composition, formed in the above manner by mixing the resin component (A) with the curing agent component (B), is introduced into the borehole over the static mixer, the threaded anchor rod is set and the mortar 12 composition is allowed to cure for 24 hours at room temperature. The threaded anchor rods, set in this way, are investigated in the manner described with respect to their average failure loads. The bond stresses, determined in this way, are summarized in the following Table 2. 5 Table 2 Bond Stress Difference (N/mm 2 ) () Cleaning Borehole treated Dry Moist Boreholes with Concrete Concrete methacryloxyalkyltri alkoxysilane (y-MEMO) Vacuumed, 3x brushed, No 18.4 + 1.1 15.0 + 0.9 -18.5 vacuumed (comparison) 2x "Putzi" No 17.6 + 1.2 11.5 + 0.6 -34.7 treatment (Inve ntion) Yes 18.1 + 0.5 17.0 + 0.7 -6.1 As the above Table shows, load values are obtained using the inventive treatment of the boreholes with a methacryloxyalkyl trialkoxysilane, which, with a clearly lesser effort for cleaning the 13 surface of the boreholes, are comparable with those obtained using a significantly more expensive cleaning method. Furthermore, the effect of the moisture of the surface of the boreholes on the load value is clearly less and this also with a clearly lower cleaning 5 expense. 14