CA1314361C - Method for protecting, renovating and restoring stone structures, monuments and the like - Google Patents
Method for protecting, renovating and restoring stone structures, monuments and the likeInfo
- Publication number
- CA1314361C CA1314361C CA000563773A CA563773A CA1314361C CA 1314361 C CA1314361 C CA 1314361C CA 000563773 A CA000563773 A CA 000563773A CA 563773 A CA563773 A CA 563773A CA 1314361 C CA1314361 C CA 1314361C
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- CA
- Canada
- Prior art keywords
- stone
- polyisocyanate prepolymer
- moisture
- weight
- capillaries
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/46—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with organic materials
- C04B41/48—Macromolecular compounds
- C04B41/488—Other macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds
- C04B41/4884—Polyurethanes; Polyisocyanates
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Paints Or Removers (AREA)
- Aftertreatments Of Artificial And Natural Stones (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Polyurethanes Or Polyureas (AREA)
- Tents Or Canopies (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Glass Compositions (AREA)
- Finishing Walls (AREA)
- Compounds Of Unknown Constitution (AREA)
Abstract
Method for protecting, renovating and restoring stone structures, monuments and the like.
Abstract The invention relates to a method for protecting, reno-vating or restoring stone structures in which the struc-ture is treated with a solution which consists of an aliphatic isocyanate and one or more organic solvents inert thereto and then the isocyanate is cured by expo-sure to moisture. The invention furthermore relates to the agents for carrying out the method consisting of a solution of aliphatic isocyanate in one or more organic solvents inert thereto.
Abstract The invention relates to a method for protecting, reno-vating or restoring stone structures in which the struc-ture is treated with a solution which consists of an aliphatic isocyanate and one or more organic solvents inert thereto and then the isocyanate is cured by expo-sure to moisture. The invention furthermore relates to the agents for carrying out the method consisting of a solution of aliphatic isocyanate in one or more organic solvents inert thereto.
Description
1 3 1 ~36 1 Method for protecting, renovating and restoring stone structures, monuments and the like Stone structures, monuments and the like, hereinafter designated for the sake of simplicity as structures, are subjected ;n the course of years to a constant exposure to the atmosphere. The surface of the structures is constantly exposed to the harmful substances contained in the atmosphere, such as carbon dioxide, carbon monox-ide, sulfur dioxide, nitrogen oxides etc., along with the moisture deposited by rain and fog. Dirt is depo-sited in the pores and together with metabolic products produced by the microorganisms, and the stone texture of the structure is destroyed, thus bringing about a more or less rapid errosion of the stone material used in the structure.
In the course of the years, this results in a continuous-ly progressing destruction of the structure.
In the case of historical structures, monuments and the like, ;n particular, this continuous process of destruction proves to be extremely unpleasant because irreplaceable assets are always lost as a result.
:
` Great efforts have already been made to stop this pro-cess of destruction and, in addition, to renovate the damage which has already occurred.
:' ~
,,, . ' ~ . . . ' . ! . ~
` 1 31 4361 For this purpose, stone materials are treated with solu-tions of silicic-acid ester. A part of its natural binder is therefore returned to the stone.
This known silicic-acid ester method is~ however, appli-cable to lime-bound materials only to a limited extent.
In addition, a further disadvantage can be seen in the fact that the pores present in the stone material are largely sealed so that the natural breathing of the stone material is impaired by the treatment.
Starting from this known prior art, it is therefore the object of the present invention to provide a new method for protecting, renovating and restoring stone struc-tures, monuments and the like which can be applied to all stone materials and which retains, ;n particular, the capillary texture present in the stone material.
This object ~is achieved according to the invention with a method of the type defined above, wherein the struc-~ , ture is treated with a solution which consists of analiphatic isocyanate and one or more organic solvents inert thereto, and then the isocyanate is cured by expo-sure to moisture.
The isocyanate used in the method according to the inven-tion is preferably a polyisocyanate prepolymer which is commercially obtainable, for example, uncler the designa-tion Desmodur E. Such a polyisocyanate prepolymer has reactive isocyanate groups which are able to react with the moisture of the air and form polymers in doing so.
The content of reactive NCO groups is preferably approx.
8.5% and th~e equivalent weight is preferably in the range of 500.
It may be remarked, however, that other polyisocyanate prepolymers, which polymerize and consequently cure after ~r~c ~h~
~. . . . :
1 3 1 ~36 1 introduction into the texture of the stone, may also be used in the method according to the invention.
The solvents used in the method according to the inven-tion should be solvents which are inert in relation to the polyisocyanate prepolymer.
Accordingly, a multiplicity of solvents is available.
The preferred solvents are chosen in accordance with as-pects such as low toxicity, inexpensiveness, good solu-tion properties, good wetting of the stone material etc.
. ~
Preferred solvents are xylene, methyl isobutyl ketone, solvent naphtha, toluene, ethyl acetate, isobutyl ace-tate, acetone and methoxypropyl acetate.
Solvent combinations can, of course, also be used for the treatment with the aliphatic isocyanate.
Preferred solvent mixtures are the following examples:
1) 30 parts by weight of xylene~ 100 parts by weight of methyl isobutyl ketone.
In the course of the years, this results in a continuous-ly progressing destruction of the structure.
In the case of historical structures, monuments and the like, ;n particular, this continuous process of destruction proves to be extremely unpleasant because irreplaceable assets are always lost as a result.
:
` Great efforts have already been made to stop this pro-cess of destruction and, in addition, to renovate the damage which has already occurred.
:' ~
,,, . ' ~ . . . ' . ! . ~
` 1 31 4361 For this purpose, stone materials are treated with solu-tions of silicic-acid ester. A part of its natural binder is therefore returned to the stone.
This known silicic-acid ester method is~ however, appli-cable to lime-bound materials only to a limited extent.
In addition, a further disadvantage can be seen in the fact that the pores present in the stone material are largely sealed so that the natural breathing of the stone material is impaired by the treatment.
Starting from this known prior art, it is therefore the object of the present invention to provide a new method for protecting, renovating and restoring stone struc-tures, monuments and the like which can be applied to all stone materials and which retains, ;n particular, the capillary texture present in the stone material.
This object ~is achieved according to the invention with a method of the type defined above, wherein the struc-~ , ture is treated with a solution which consists of analiphatic isocyanate and one or more organic solvents inert thereto, and then the isocyanate is cured by expo-sure to moisture.
The isocyanate used in the method according to the inven-tion is preferably a polyisocyanate prepolymer which is commercially obtainable, for example, uncler the designa-tion Desmodur E. Such a polyisocyanate prepolymer has reactive isocyanate groups which are able to react with the moisture of the air and form polymers in doing so.
The content of reactive NCO groups is preferably approx.
8.5% and th~e equivalent weight is preferably in the range of 500.
It may be remarked, however, that other polyisocyanate prepolymers, which polymerize and consequently cure after ~r~c ~h~
~. . . . :
1 3 1 ~36 1 introduction into the texture of the stone, may also be used in the method according to the invention.
The solvents used in the method according to the inven-tion should be solvents which are inert in relation to the polyisocyanate prepolymer.
Accordingly, a multiplicity of solvents is available.
The preferred solvents are chosen in accordance with as-pects such as low toxicity, inexpensiveness, good solu-tion properties, good wetting of the stone material etc.
. ~
Preferred solvents are xylene, methyl isobutyl ketone, solvent naphtha, toluene, ethyl acetate, isobutyl ace-tate, acetone and methoxypropyl acetate.
Solvent combinations can, of course, also be used for the treatment with the aliphatic isocyanate.
Preferred solvent mixtures are the following examples:
1) 30 parts by weight of xylene~ 100 parts by weight of methyl isobutyl ketone.
2) 250 parts by weight of isobutyl acetate, 180 parts by we;ght of xylene, 350 parts by weight of solvent `~ naphtha.
3) 250 parts by weight of methyl isobutyl ketone, 180 parts by weight of xylene, 350 parts by weight of solvent naphtha.
4) 30 parts by weight of xylene, 80 parts by weight of acetone, 80 parts by weight of isobutyl acetate.
5) 10G parts by weight of ethyl acetate, 70 parts by weight of toluene, 30 parts by weight of acetone.
6) 100 parts by weight of toluene, 30 parts by weight of acetone, 30 parts by weight of methoxypropyl acetate.
The method according to the invention for treat;ng struc-tures can be subdivided into those ~ethods which are used exclusively for protecting as yet undamaged 131~361 structures, furthermore into those for the renovation of already damaged structures and finaLly into methods for restoring heavily damaged structures.
According to th;s classification, the method according to the invention comprises, on the one hand, the so-called hydrophobizing of the structure in which hydrophobizing ;s carried out superficially by applying a solution of 1 to la parts by weight of the aliphatic isocyanate and 99 to 90 parts by weight of the solvent inert thereto or the solvent combination inert thereto~
::
As a result of this measure of the method, the isocyanate solution penetrates a few mm into the stone material.
The solvent evaporates and the isocyanate reacts with the moisture to form a polymer film which coats the surface of the stone and the entire capillary system, and specific-ally, the capillary walls to the depth specified above, with a polymer film.
~' The capillaries themselves, however, remain open and, con-sequently, the vapor diffusion capability of the stone material remains intact to the greatest possible extent. `
In this manner, a hydrophobizing of the surface is achieved which has the eff~ect that the stone becomes water-repel-lent. ~The rain and the dirt applied with it therefore trickle off the stone and the dirt is no longer deposited on the stone~ Consequently, there is no longer any habitat for the microorganisms which, as a consequence of their metabolic products, cause an initial incipient so~ution of the stone texture and as a result, provide the condition for the penetration of further moisture and further dirt and for exposure to the harmful substances contained in the atmosphere.
The concentration of the ;socyanate in the solvent nec-essary for the hydrophobizing depends on the size of the caplllary system of the stone mater;al. A quite Foarse .
.
, 131~361 structure of the stone requires a substantially higher proportion of isocyanate in the solution than a fine capillary structure.
.
The concentration of the solution is therefore expedient-ly determined on the basis of empirical tests.
For the renovation of structures which are already dama-ged, according to the method according to the invention, a solutian of 3 to 15% by weight of aliphatic isocyanate and 97 to 85% by weight of the solvent inert thereto or the solvent mixtures inert thereto are applied.
;
This solution penetrates into the pores, coats the capil-lary walls with a polymer film and thus consolidates the already damaged stone texture. The capillaries them-selves, however, remain intact and continue to be avail-able for the vapor diffusion of the stone.
; In the method according to the invention, no closed sur-face layer is produced and no direct chemical reaction takes place with the stone ~aterial itself. No crust is formed.
:, ~
The consolidation by the method according to the inven-tion takes place, on the contrary, only as a result of the penetration into the capillary spaces and the lining of the walls of the capillaries with the polymer film~
which has the result that the nature of the stone is completely irrelevant for the method according to the invention and, accordingly, also in contrast to the known silicic acid ester method, does not present any limitation for the method according to the invention.
The restoration of heavily damaged structures is carried out by the method according to the invention by applying a moldable compound from a solution of 3 to 70% by weight of aliphatic isocyanate in 97 to 30% by weight o~ solvent inert thereto or of solvent mixture inert thereto and ~ - 6 - 1 3 1 ~ 3 6 1 mineral constituents. A preferred concentration range is 8 to 30% by ueight of isocyanate and 92 to 70% by weight of solvent mixture.
In the case of a moldable stone replac2ment compound ap-plied in such a manner, the solvent evaporates and the isocyanate left behind cures under the influence of mois-ture and the cured compound thus replaces the stone sub-stance alr~ady lost, suitable choice of the mineral con-stituents used in the moldable compound expediently ensur-ing that the stone parts replaced in this manner have the same appearance as the remaining stone~
Process techniques usual per se can be applied for the application of the solutions in the method according to the invention. For hydrophobi~ing, a spraying on, brush-ing on or flooding may expediently be used. At the same time, for the renovation of already damaged structures, an impregnation in the solution, or if this is not possi-ble because of the size of the structure, a multiple brushing on or spraying on or application by means of a flowing film (flooding) is suitable.
The invention is explained in more detail on the basis of the examples below and at the same time the stone samples obtained, treated with the method according to the invention, are tested in comparison with untreated stone samples for their properties and the results are compared.
Example 1 Mechanical rupture tests For the rupture tests, pris0s measuring 4 x 4 x 16 cm were cut from Soskut soft lime quarrystone. The test specimens were saturated by absorption from a solvent layer as a consequence of capillary activity and tested after the treatment in a comparison with the untreated 131~361 specimens. In this process, the following results were obtained:
-Soskw- quarrystone test i Untreated test Treatment with the polyisocyanate prepolymer specimen solution in 2 mixture of SO;'O by weight of xylene and 50% by weight of methyl isobutyl ketone Cor,centration Increase in 7 of the solu-tion in ;~ by a ~e i ght ~ _ a 32.5 ¦ 10 3û.247 6 273 46 I
_ Chipped stone froal the surface layer of the Sosku. quarry Untreated test Treatment with the polyisocyanate prepolymer spec i men so l ut i on Concent rat i on Inc rease i n %
of the solu-tion in % by !i a weight a 18.0 3a I 10 32 48 300 60 ~ = tensile strength in bending N/mm2 a = compression strength N/~m Example 2 .
~;., .
E~ohm wear-resistance test of weathered Soskut soft lime quar rys tone The surface of quarrystone blanks was impregnated w;th a 12% polyisocyanate prepolymer solut;on in a mixture of 50% by weight of xylene and 50% by weight of methyl iso-butyl ketone, the solution being drawn into the stone under the influence of capillary activity.
The stone specimen treated in this manner was sub jected to the B'ohm wear-resistance test along with an untreated ;~ stone specimen. in this process, the following results w e r e o b t a i n e d :
1314~61 aefore the After the Difference Increase wear tes~ wear test Mass Thick- Mass Th;ck- Mass Thick-ness ness ness g mm g mm g mm Untreated38Z.741.3285.831.296~9 10.1 35%
Treated 332.440.6 275.834.056.6 6.6 _ Example 3 Vapor diffusion test of Soskut soft lime quarrystone The tests were determined on the basis of the binding to CaCl2 of quantities of moisture which were absofbed from the air and which had diffused through disk-shaped test specimens having a diameter of 7 cm. The concentra-tion of the polyisocyanate prepolymer solutions used for treating the specimens in a mixture of 5û% by weight of xylene and 50% by weight of methyl isobutyl ketone was 15% by weight. The quarrystone disk had absorbed the solution as a consequence of the capillary activity.
The following results were obtained:
.
Parameter Increase in Decrease in the Test time rhickness weight of the vapor diffusion quantity of in %
CaCl h _ cm 2 9 Untreated 984 2.20 19.5 Treated 984 2.23 15.9 18.5 Example 4 ~' -Frost resistance test : . _ Prisms measuring 4 x 4 x 16 cm were manufactured from the Soskut soft lime quarrystone and similar test 1 3 1 ~ 3 6 1 specimens were produced to test the stone substitute material n The polyisocyanate prepolymer solution in a mixture of 50% by weight of xylene and 50~ by weight of methyl iso-butyl ketone used for the treatment was a 12~ by weight solution which the test specimen absorbed from a solu-tion 35 a result of the capillary activity.
Test methodo The number of cycles between freezing to -20C and break-down in water at +20C was tested. The number of cycles which the specimen passed through without damage was compared.
The increase in frost resistance of the Soskut soft lime-stone as a consequence of treatment with the solution according to the invention was 60%.
Example 5 Water absorption test In each case 5 pieces of the Ihrl sandstone and of the Udelfang sandstone cut to the same si~e were subjected to storage in water in the untreated state and after im-pregnation with the 6% by weight polyisocyanate prepolymer solution according to the invention in a mixture of 50X
by weight ~ylene and 50% by weight methyl isobutyl ketone.
The results are listed below:
- 10 - 1 3 1 ~36 1 Ihrl sandstone (untreated) Specimen Weight, g Di~ensions, mm No. Days of storage in water After Length Width Height _ 5 _ 6 7 8 drying _ _ 1 314.33 314.40 314.54 314.54 294.10 52 52 52 2 312.63 312.73 312.82 312.82 292.05 52 52 51 3 31û.98 311.09 311.22 311.22 290.73 51 51 52 4 310.17 310.33 310.39 310.39 289.51 51 51 52 S 309.47 309.66 309.78 309.78 289.58 51 51 52 -` .
-- - :
Specimen Weight per Water absorp-No. Weight, g unit volume tion - Dry Saturated Water ab- kg/dm3 % by X by with water sorption mass volume W
1 294.10 314.54 20.44 2.09 6.95 14.54 2 292.05 312.82 2û.77 2.12 7.11 15.06 3 290.73 311.22 20.49 2.15 7.05 15.15 4 289.51 310.39 20.88 2.14 7.21 15.44 -~
S 289n58 309.78 20.20 2.14 6.98 14.94 Average: 7.06 15.02 ~,: ~ ~'-Ihrl sandstone (impregnated with the solution according to the inven.ion) Specimen Weight, g Dimensions, mm No. Days of~storage in water After Length Width Height S 6 _ 7 8 drying 1a 297.49 297.67 297.86 297.86 292.88 52 51 51 2a 297.65 297.84 298.02 298.02 292.93 52 51 51 3a 297.04 297.18 297.31 297.31 292.72 52 51 S0 4a 293.58 293.70 293.i34 293.i95 2a9.40 52 51 S0 Sa 292.39 292.54 292.66 292.66 288.14 52 51 sn ~ -131~36~
.. . . . . _ _ Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 % by X by with water sorption mass volume Wa .... _ _ 1a 292.88 297.86 4.98 2.17 1.70 3.68 2a 292.93 298.02 5.09 2.17 1.74 3.76 3a 292.72 297.31 4.59 2.16 1.57 3.39 4a 289.46 293.85 4.45 2.18 1.54 3.36 5a 288.14 292.66 4.52 2.17 1.57 3.41 Average: 1.62 3.52 Udelfang sandstone tuntreated) Specimen Weight, g Dimensions, mm No. Days of storage in water After Length Width Height 5 6 7 8 drying 1 277.61 277.90 278.07 278.07 256.11 51 51 50 2 277.37 277.60 277.77 277.77 256.47 51 51 50 3 281.17 281.41 281.66 281.66 261.53 51 51 50 4 274.53 274.85 275.05 275.05 251.95 51 51 50 269.33 269.61 269.81 269.81 245.43 51 51 50 , :~
Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 X by X by with water sorption mass volume Wa 1 256.11 278.07 21.96 1.97 8.57 16.87 2 256.47 277.77 21.30 1~97 8.31 16.38 3 261.53 281.66 20.13 2.01 7.70 15.48 4 251.95 275.05 23.10 1.94 9.17 17.76 245.43 269.81 24.38 1.89 9.93 18.75 _ .
Average: 8.74 17.05 131~361 ~delfang sandstone (impregnated with the solution according to the invention;
Specimen Weight, g Dimensions, mm No. Days of storage in water After Length Width Height 5 6 7 8 drying . .
1a 27û.09 270.49 270.85 271.10 267.12 50 50 51 2a 248.19 248.95 249.61 250.47 243.10 50 50 51 3a 251.81 252.38 252.80 253.2û 248.26 50 50 51 4a 250.56 250.92 251.14 251.50 247.89 50 50 51 5a 250.01 250.80 251.38 252.08 245.25 50 50 51 . . _ _ Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 X by Z by with water sorption mass volume W ;~
1a 267.12 271.10 3.98 2.10 1.49 3.12 2a 243.10 250.47 7.37 1.91 3.03 5.78 3a 248.26 253.20 4.94 1.95 1.99 3.87 4a 247.89 251.50 3.61 1.94 1.46 2.83 5a 245.25 252.00 6.75 1~92 2.75 5.29 - - -Average: 2.14 4.18 Example 6 Modified Quervain crystallization test : :~, , _ The same Udelfang sandstone test specimens were used as in Example S (5 pieces untreated and 5 pieces treatecl with the soLution according to the invention as in Exam-ple 5). The specimens were subjected to the Quervain crystallization test using 10~ sodium sulfate solution.
After 10 cycles sand formation was observed in the un-treated test specimens, ~hile, in the case of the treated test specimens, there was still no change even after 20 cycles.
~r~e~ rk
The method according to the invention for treat;ng struc-tures can be subdivided into those ~ethods which are used exclusively for protecting as yet undamaged 131~361 structures, furthermore into those for the renovation of already damaged structures and finaLly into methods for restoring heavily damaged structures.
According to th;s classification, the method according to the invention comprises, on the one hand, the so-called hydrophobizing of the structure in which hydrophobizing ;s carried out superficially by applying a solution of 1 to la parts by weight of the aliphatic isocyanate and 99 to 90 parts by weight of the solvent inert thereto or the solvent combination inert thereto~
::
As a result of this measure of the method, the isocyanate solution penetrates a few mm into the stone material.
The solvent evaporates and the isocyanate reacts with the moisture to form a polymer film which coats the surface of the stone and the entire capillary system, and specific-ally, the capillary walls to the depth specified above, with a polymer film.
~' The capillaries themselves, however, remain open and, con-sequently, the vapor diffusion capability of the stone material remains intact to the greatest possible extent. `
In this manner, a hydrophobizing of the surface is achieved which has the eff~ect that the stone becomes water-repel-lent. ~The rain and the dirt applied with it therefore trickle off the stone and the dirt is no longer deposited on the stone~ Consequently, there is no longer any habitat for the microorganisms which, as a consequence of their metabolic products, cause an initial incipient so~ution of the stone texture and as a result, provide the condition for the penetration of further moisture and further dirt and for exposure to the harmful substances contained in the atmosphere.
The concentration of the ;socyanate in the solvent nec-essary for the hydrophobizing depends on the size of the caplllary system of the stone mater;al. A quite Foarse .
.
, 131~361 structure of the stone requires a substantially higher proportion of isocyanate in the solution than a fine capillary structure.
.
The concentration of the solution is therefore expedient-ly determined on the basis of empirical tests.
For the renovation of structures which are already dama-ged, according to the method according to the invention, a solutian of 3 to 15% by weight of aliphatic isocyanate and 97 to 85% by weight of the solvent inert thereto or the solvent mixtures inert thereto are applied.
;
This solution penetrates into the pores, coats the capil-lary walls with a polymer film and thus consolidates the already damaged stone texture. The capillaries them-selves, however, remain intact and continue to be avail-able for the vapor diffusion of the stone.
; In the method according to the invention, no closed sur-face layer is produced and no direct chemical reaction takes place with the stone ~aterial itself. No crust is formed.
:, ~
The consolidation by the method according to the inven-tion takes place, on the contrary, only as a result of the penetration into the capillary spaces and the lining of the walls of the capillaries with the polymer film~
which has the result that the nature of the stone is completely irrelevant for the method according to the invention and, accordingly, also in contrast to the known silicic acid ester method, does not present any limitation for the method according to the invention.
The restoration of heavily damaged structures is carried out by the method according to the invention by applying a moldable compound from a solution of 3 to 70% by weight of aliphatic isocyanate in 97 to 30% by weight o~ solvent inert thereto or of solvent mixture inert thereto and ~ - 6 - 1 3 1 ~ 3 6 1 mineral constituents. A preferred concentration range is 8 to 30% by ueight of isocyanate and 92 to 70% by weight of solvent mixture.
In the case of a moldable stone replac2ment compound ap-plied in such a manner, the solvent evaporates and the isocyanate left behind cures under the influence of mois-ture and the cured compound thus replaces the stone sub-stance alr~ady lost, suitable choice of the mineral con-stituents used in the moldable compound expediently ensur-ing that the stone parts replaced in this manner have the same appearance as the remaining stone~
Process techniques usual per se can be applied for the application of the solutions in the method according to the invention. For hydrophobi~ing, a spraying on, brush-ing on or flooding may expediently be used. At the same time, for the renovation of already damaged structures, an impregnation in the solution, or if this is not possi-ble because of the size of the structure, a multiple brushing on or spraying on or application by means of a flowing film (flooding) is suitable.
The invention is explained in more detail on the basis of the examples below and at the same time the stone samples obtained, treated with the method according to the invention, are tested in comparison with untreated stone samples for their properties and the results are compared.
Example 1 Mechanical rupture tests For the rupture tests, pris0s measuring 4 x 4 x 16 cm were cut from Soskut soft lime quarrystone. The test specimens were saturated by absorption from a solvent layer as a consequence of capillary activity and tested after the treatment in a comparison with the untreated 131~361 specimens. In this process, the following results were obtained:
-Soskw- quarrystone test i Untreated test Treatment with the polyisocyanate prepolymer specimen solution in 2 mixture of SO;'O by weight of xylene and 50% by weight of methyl isobutyl ketone Cor,centration Increase in 7 of the solu-tion in ;~ by a ~e i ght ~ _ a 32.5 ¦ 10 3û.247 6 273 46 I
_ Chipped stone froal the surface layer of the Sosku. quarry Untreated test Treatment with the polyisocyanate prepolymer spec i men so l ut i on Concent rat i on Inc rease i n %
of the solu-tion in % by !i a weight a 18.0 3a I 10 32 48 300 60 ~ = tensile strength in bending N/mm2 a = compression strength N/~m Example 2 .
~;., .
E~ohm wear-resistance test of weathered Soskut soft lime quar rys tone The surface of quarrystone blanks was impregnated w;th a 12% polyisocyanate prepolymer solut;on in a mixture of 50% by weight of xylene and 50% by weight of methyl iso-butyl ketone, the solution being drawn into the stone under the influence of capillary activity.
The stone specimen treated in this manner was sub jected to the B'ohm wear-resistance test along with an untreated ;~ stone specimen. in this process, the following results w e r e o b t a i n e d :
1314~61 aefore the After the Difference Increase wear tes~ wear test Mass Thick- Mass Th;ck- Mass Thick-ness ness ness g mm g mm g mm Untreated38Z.741.3285.831.296~9 10.1 35%
Treated 332.440.6 275.834.056.6 6.6 _ Example 3 Vapor diffusion test of Soskut soft lime quarrystone The tests were determined on the basis of the binding to CaCl2 of quantities of moisture which were absofbed from the air and which had diffused through disk-shaped test specimens having a diameter of 7 cm. The concentra-tion of the polyisocyanate prepolymer solutions used for treating the specimens in a mixture of 5û% by weight of xylene and 50% by weight of methyl isobutyl ketone was 15% by weight. The quarrystone disk had absorbed the solution as a consequence of the capillary activity.
The following results were obtained:
.
Parameter Increase in Decrease in the Test time rhickness weight of the vapor diffusion quantity of in %
CaCl h _ cm 2 9 Untreated 984 2.20 19.5 Treated 984 2.23 15.9 18.5 Example 4 ~' -Frost resistance test : . _ Prisms measuring 4 x 4 x 16 cm were manufactured from the Soskut soft lime quarrystone and similar test 1 3 1 ~ 3 6 1 specimens were produced to test the stone substitute material n The polyisocyanate prepolymer solution in a mixture of 50% by weight of xylene and 50~ by weight of methyl iso-butyl ketone used for the treatment was a 12~ by weight solution which the test specimen absorbed from a solu-tion 35 a result of the capillary activity.
Test methodo The number of cycles between freezing to -20C and break-down in water at +20C was tested. The number of cycles which the specimen passed through without damage was compared.
The increase in frost resistance of the Soskut soft lime-stone as a consequence of treatment with the solution according to the invention was 60%.
Example 5 Water absorption test In each case 5 pieces of the Ihrl sandstone and of the Udelfang sandstone cut to the same si~e were subjected to storage in water in the untreated state and after im-pregnation with the 6% by weight polyisocyanate prepolymer solution according to the invention in a mixture of 50X
by weight ~ylene and 50% by weight methyl isobutyl ketone.
The results are listed below:
- 10 - 1 3 1 ~36 1 Ihrl sandstone (untreated) Specimen Weight, g Di~ensions, mm No. Days of storage in water After Length Width Height _ 5 _ 6 7 8 drying _ _ 1 314.33 314.40 314.54 314.54 294.10 52 52 52 2 312.63 312.73 312.82 312.82 292.05 52 52 51 3 31û.98 311.09 311.22 311.22 290.73 51 51 52 4 310.17 310.33 310.39 310.39 289.51 51 51 52 S 309.47 309.66 309.78 309.78 289.58 51 51 52 -` .
-- - :
Specimen Weight per Water absorp-No. Weight, g unit volume tion - Dry Saturated Water ab- kg/dm3 % by X by with water sorption mass volume W
1 294.10 314.54 20.44 2.09 6.95 14.54 2 292.05 312.82 2û.77 2.12 7.11 15.06 3 290.73 311.22 20.49 2.15 7.05 15.15 4 289.51 310.39 20.88 2.14 7.21 15.44 -~
S 289n58 309.78 20.20 2.14 6.98 14.94 Average: 7.06 15.02 ~,: ~ ~'-Ihrl sandstone (impregnated with the solution according to the inven.ion) Specimen Weight, g Dimensions, mm No. Days of~storage in water After Length Width Height S 6 _ 7 8 drying 1a 297.49 297.67 297.86 297.86 292.88 52 51 51 2a 297.65 297.84 298.02 298.02 292.93 52 51 51 3a 297.04 297.18 297.31 297.31 292.72 52 51 S0 4a 293.58 293.70 293.i34 293.i95 2a9.40 52 51 S0 Sa 292.39 292.54 292.66 292.66 288.14 52 51 sn ~ -131~36~
.. . . . . _ _ Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 % by X by with water sorption mass volume Wa .... _ _ 1a 292.88 297.86 4.98 2.17 1.70 3.68 2a 292.93 298.02 5.09 2.17 1.74 3.76 3a 292.72 297.31 4.59 2.16 1.57 3.39 4a 289.46 293.85 4.45 2.18 1.54 3.36 5a 288.14 292.66 4.52 2.17 1.57 3.41 Average: 1.62 3.52 Udelfang sandstone tuntreated) Specimen Weight, g Dimensions, mm No. Days of storage in water After Length Width Height 5 6 7 8 drying 1 277.61 277.90 278.07 278.07 256.11 51 51 50 2 277.37 277.60 277.77 277.77 256.47 51 51 50 3 281.17 281.41 281.66 281.66 261.53 51 51 50 4 274.53 274.85 275.05 275.05 251.95 51 51 50 269.33 269.61 269.81 269.81 245.43 51 51 50 , :~
Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 X by X by with water sorption mass volume Wa 1 256.11 278.07 21.96 1.97 8.57 16.87 2 256.47 277.77 21.30 1~97 8.31 16.38 3 261.53 281.66 20.13 2.01 7.70 15.48 4 251.95 275.05 23.10 1.94 9.17 17.76 245.43 269.81 24.38 1.89 9.93 18.75 _ .
Average: 8.74 17.05 131~361 ~delfang sandstone (impregnated with the solution according to the invention;
Specimen Weight, g Dimensions, mm No. Days of storage in water After Length Width Height 5 6 7 8 drying . .
1a 27û.09 270.49 270.85 271.10 267.12 50 50 51 2a 248.19 248.95 249.61 250.47 243.10 50 50 51 3a 251.81 252.38 252.80 253.2û 248.26 50 50 51 4a 250.56 250.92 251.14 251.50 247.89 50 50 51 5a 250.01 250.80 251.38 252.08 245.25 50 50 51 . . _ _ Specimen Weight per Water absorp-No. Weight, g unit volume tion Dry Saturated Water ab- kg/dm3 X by Z by with water sorption mass volume W ;~
1a 267.12 271.10 3.98 2.10 1.49 3.12 2a 243.10 250.47 7.37 1.91 3.03 5.78 3a 248.26 253.20 4.94 1.95 1.99 3.87 4a 247.89 251.50 3.61 1.94 1.46 2.83 5a 245.25 252.00 6.75 1~92 2.75 5.29 - - -Average: 2.14 4.18 Example 6 Modified Quervain crystallization test : :~, , _ The same Udelfang sandstone test specimens were used as in Example S (5 pieces untreated and 5 pieces treatecl with the soLution according to the invention as in Exam-ple 5). The specimens were subjected to the Quervain crystallization test using 10~ sodium sulfate solution.
After 10 cycles sand formation was observed in the un-treated test specimens, ~hile, in the case of the treated test specimens, there was still no change even after 20 cycles.
~r~e~ rk
Claims (6)
1. Method for hydrophobizing as yet undamaged stone structures having capillaries and being of open porosity, which comprises applying to said stone structure a solution consisting essentially of 1-10% by weight of a polyisocyanate prepolymer in at least one vaporizable organic solvent inert to said polyisocyanate prepolymer which has reactive isocyanate groups capable of reacting with moisture to form polymers, said reactive isocyanate groups in said solution remaining unreacted until contacted with moisture, said polyisocyanate prepolymer solution penetrating into the pores of the capillary system; and permitting said organic solvent to evaporate, whereby the capillaries remain open and the polyisocyanate prepolymer which remains, upon reaction with moisture, forms a polymeric film on the walls of said pores, thus coating the walls of the capillaries with the formed polymeric film while the capillaries themselves remain open so that the vapor diffusion capability of the stone material remains substantially intact.
2. Method for consolidation of stone structures damaged by atmosphere or microorganisms, which comprises applying to said stone structure a solution consisting essentially of 3-15% by weight of a polyisocyanate prepolymer in at least one vaporizable organic solvent inert to said polyisocyanate prepolymer which has reactive isocyanate groups capable of reacting with moisture to form polymers, said reactive isocyanate groups in said solution remaining unreacted until contacted with moisture said polyisocyanate prepolymer solution penetrating into the pores and capillary spaces of the capillary system; and permitting said organic solvent to evaporate, whereby the capillaries remain open and the polyisocyanate prepolymer which remains, upon reaction with moisture, forms a polymeric film on the walls of said pores, thus coating the walls of the capillaries with the formed polymeric film and consolidating the stone structure while the capillaries themselves remain open so that the vapor diffusion capability of the stome material remains substantially intact.
3. Method for restoring stone structures heavily damaged by atmosphere or microorganisms with loss of stone by replacing said lost stone with a moldable composition which consists of a polyisocyanate prepolymer, at least one vaporizable organic solvent, inert to said polyisocyanate prepolymer and mineral constituents, which comprises applying said composition to said stone structure, said composition containing 8-30% by weight of said polyisocyanate prepolymer in said vaporizable organic solvent inert to said polyisocyanate prepolymer, which has reactive isocyanate groups capable of reacting with moisture to form polymers, said reactive isocyanate groups in said composition remaining unreacted until contacted with moisture, said composition penetrating into the pores of the capillary system;
and permitting said organic solvent to evaporate, whereby said polyisocyanate cures, upon reaction with moisture, thus replacing the stone substance already lost a polymeric film on the walls of said pores and coating the walls of the capillaries with the formed polymeric film while the capillaries themselves remain open so that the vapor diffusion capability of the stone material remains substantially intact.
and permitting said organic solvent to evaporate, whereby said polyisocyanate cures, upon reaction with moisture, thus replacing the stone substance already lost a polymeric film on the walls of said pores and coating the walls of the capillaries with the formed polymeric film while the capillaries themselves remain open so that the vapor diffusion capability of the stone material remains substantially intact.
4. Method according to claim 1, 2 or 3 wherein said polyisocyanate prepolymer is an aliphatic isocyanate.
5. Method according to claim 1, 2 or 3 wherein said polyisocyanate prepolymer contains approximately 8.5% by weight of reactive NCO groups.
6. Method according to claim 1, 2 or 3 wherein said solvent is selected from the group consisting of xylene, methyl isobutyl ketone, solvent naphtha, toluene, ethyl acetate, isobutyl acetate, acetone and methoxypropyl acetate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19873712967 DE3712967A1 (en) | 1987-04-16 | 1987-04-16 | METHOD FOR PROTECTING, RENOVATING AND RESTORING STONE CONSTRUCTIONS, MONUMENTS AND THE LIKE |
| DEP3712967.8 | 1987-04-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1314361C true CA1314361C (en) | 1993-03-16 |
Family
ID=6325787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000563773A Expired - Fee Related CA1314361C (en) | 1987-04-16 | 1988-04-11 | Method for protecting, renovating and restoring stone structures, monuments and the like |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0287026B1 (en) |
| AT (1) | ATE58365T1 (en) |
| AU (1) | AU600357B2 (en) |
| CA (1) | CA1314361C (en) |
| CS (1) | CS270584B2 (en) |
| DD (1) | DD281216A5 (en) |
| DE (2) | DE3712967A1 (en) |
| ES (1) | ES2019117B3 (en) |
| FI (1) | FI94127C (en) |
| PL (1) | PL150756B1 (en) |
| WO (1) | WO1988007982A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2643899B1 (en) * | 1989-03-01 | 1992-11-20 | Crea Eric | Renovation of external marble and stone |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1194754B (en) * | 1963-10-09 | 1965-06-10 | Hoechst Ag | Water repellent for building protection |
| FI237174A (en) * | 1973-08-10 | 1975-02-11 | Nya Asfalt Ab | |
| DE2713857A1 (en) * | 1977-03-29 | 1978-10-12 | Sager & Woerner | Surface impregnation of concrete, plaster, bricks, natural stone etc. - using compsn. contg. epoxide, isocyanate and opt. organo-silicon cpd. |
| AT351997B (en) * | 1977-12-01 | 1979-08-27 | Bartak Gottlieb | INSULATING LIQUID FOR NIGHTLY INSULATING MASONRY AGAINST RISING LIQUID |
| DE3135941A1 (en) * | 1981-09-10 | 1983-03-24 | Misawa Homes K.K., Tokyo | Process for the surface treatment of components consisting of lightweight aerated concrete |
| DE3629061A1 (en) * | 1986-08-27 | 1988-03-03 | Bayer Ag | IMPREGNANT AND ITS USE |
| JPH0755851B2 (en) * | 1987-02-20 | 1995-06-14 | 宇部興産株式会社 | High-strength cement hardened body and method for producing the same |
-
1987
- 1987-04-16 DE DE19873712967 patent/DE3712967A1/en active Granted
-
1988
- 1988-04-11 CA CA000563773A patent/CA1314361C/en not_active Expired - Fee Related
- 1988-04-12 WO PCT/DE1988/000226 patent/WO1988007982A1/en active IP Right Grant
- 1988-04-12 DE DE8888105787T patent/DE3861045D1/en not_active Expired - Lifetime
- 1988-04-12 EP EP88105787A patent/EP0287026B1/en not_active Expired - Lifetime
- 1988-04-12 AU AU15479/88A patent/AU600357B2/en not_active Ceased
- 1988-04-12 ES ES88105787T patent/ES2019117B3/en not_active Expired - Lifetime
- 1988-04-12 AT AT88105787T patent/ATE58365T1/en not_active IP Right Cessation
- 1988-04-15 CS CS882587A patent/CS270584B2/en unknown
- 1988-04-15 DD DD88314798A patent/DD281216A5/en not_active IP Right Cessation
- 1988-04-15 PL PL1988271855A patent/PL150756B1/en unknown
-
1989
- 1989-10-12 FI FI894835A patent/FI94127C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1988007982A1 (en) | 1988-10-20 |
| FI94127C (en) | 1995-07-25 |
| CS270584B2 (en) | 1990-07-12 |
| DE3712967A1 (en) | 1988-12-22 |
| PL150756B1 (en) | 1990-06-30 |
| CS258788A2 (en) | 1989-11-14 |
| AU1547988A (en) | 1988-11-04 |
| AU600357B2 (en) | 1990-08-09 |
| ES2019117B3 (en) | 1991-06-01 |
| EP0287026B1 (en) | 1990-11-14 |
| DE3861045D1 (en) | 1990-12-20 |
| DD281216A5 (en) | 1990-08-01 |
| EP0287026A1 (en) | 1988-10-19 |
| DE3712967C2 (en) | 1989-04-13 |
| PL271855A1 (en) | 1989-02-06 |
| ATE58365T1 (en) | 1990-11-15 |
| FI94127B (en) | 1995-04-13 |
| FI894835A0 (en) | 1989-10-12 |
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