Disclosed is a waterproofing agent for repairing a damaged portion of a waterproof sheet spread on the ground, and to a waterproof sheet repair method that uses this waterproofing agent.
Waterproof sheets are used in waterproof structures such as industrial waste disposal sites and man-made ponds. In these waterproof structures, seepage of water into the ground can be prevented by spreading a waterproof sheet on the ground.
In these types of waterproof structures, the waterproof sheet may be damaged, and in such cases, the waterproof sheet is repaired. Methods used to repair waterproof sheets include exposing the damaged location by excavating soil and other debris from on top of the waterproof sheet, visually confirming the damaged location, and affixing a patch to that location. However, in the case of such repair methods, the bothersome work of having to excavate soil and other debris is employed, thereby resulting in the problem of employing considerable time and labor.
In order to resolve such problems, a repair method has been proposed in which a waterproof sheet is repaired by inserting a nozzle into debris on the waterproof sheet and injecting a thermoplastic repair agent towards a damaged location of the waterproof sheet (see Japanese Patent Publication No. 3673972).
In the repair method described above, a waterproof sheet is repaired by injecting a warmed repair agent into a damaged location. In this case, in addition to employing a mechanism for warming the repair agent, there was also the problem of difficulty in controlling the temperature of the repair agent.
According to an exemplary aspect, disclosed is a urethane-based waterproofing agent used to repair a waterproof sheet, comprising: a primary agent containing an isocyanate component, and a curing agent containing a polyester polyol obtained from castor oil, and a plasticizing agent component, wherein the primary agent and the curing agent are mixed.
According to an exemplary aspect, disclosed is a method for determining whether a waterproof sheet spread on the ground is damaged and for repairing a damaged portion of the waterproof sheet, the method comprising: acquiring an electrical status through an electrically conductive mat arranged between upper and lower waterproof sheets, and in a case where the resulting electrical status indicates seepage, injecting a urethane-based waterproofing agent, obtained by mixing a primary agent containing an isocyanate component with a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, to seal the damaged portion of the upper waterproof sheet with the urethane-based waterproofing agent.
According to an exemplary aspect, disclosed is a system for determining whether a waterproof sheet spread on the ground is damaged and for repairing a damaged portion of the waterproof sheet, the system comprising: upper and lower waterproof sheets, an electrically conductive mat arranged between the upper and lower waterproof sheets, wherein the electrically conductive mat includes a plurality of electrodes, a urethane-based waterproofing agent, obtained by mixing a primary agent containing an isocyanate component with a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, and an injector for injecting the urethane-based waterproofing agent to seal the damaged portion of the upper waterproof sheet with the urethane-based waterproofing agent.
According to an exemplary aspect, provided is a waterproofing agent for a waterproof sheet that does not require heating and can be handled easily, and a waterproof sheet repair method that uses this waterproofing agent.
According to an exemplary aspect, by mixing a primary agent containing an isocyanate component with a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, a urethane-based waterproofing agent can be obtained that has viscosity (softness) suitable for construction work without having to be warmed.
For example, disclosed is a urethane-based waterproofing agent for repairing a waterproof sheet, provided with a primary agent containing an isocyanate compound and a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, wherein the primary agent and the curing agent are mixed.
In addition, disclosed is an exemplary repair method for repairing a damaged portion of a waterproof sheet spread on the ground, comprising a step for acquiring an electrical status through an electrically conductive mat arranged between layered waterproof sheets, and in the case the resulting electrical status indicates seepage, a step for injecting a urethane-based waterproofing agent, obtained by mixing a primary agent containing an isocyanate component with a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, from the top side of the waterproof sheet and sealing the damaged portion of the waterproof sheet with the urethane-based waterproofing agent.
For example, the primary agent may be a mixture of polymethylene polyphenyl polyisocyanate and 4,4′-diphenylmethane diisocyanate, and the plasticizing agent component may be diisononyl adipate.
For example, the curing agent may further contain a powder. The powder may be calcium carbonate.
For example, a waterproofing agent for a waterproof sheet that does not require warming and can be handled easily, and a waterproof sheet repair method that uses this waterproofing agent, can be provided.
a) is a drawing for schematically explaining the arrangement of a measuring electrode and a damaged location, according to an exemplary aspect.
b) is a drawing for explaining a waterproof structure for a repair test, according to an exemplary aspect.
First, an explanation is provided of a waterproofing agent for repairing a damaged location of a waterproof sheet. The waterproofing agent used in an exemplary embodiment can be a urethane-based waterproofing agent obtained by mixing a primary agent containing an isocyanate component with a curing agent containing a polyol component and a plasticizing agent component. For example, waterproofing agents are used that were prepared according to the composition of formula A and the composition of formula B shown in
Crude MDI, for example, Cosmonate M-200 (trade name), manufactured by Mitsui Chemicals Polyurethanes Inc., can be used for the primary agent. This M-200 is a mixture of polymethylene polyphenyl polyisocyanate (PMDI) and 4,4′-diphenylmethane diisocyanate (MDI), and contains polymethylene polyphenyl polyisocyanate at a ratio of 60% to 70% and 4,4′-diphenylmethane diisocyanate as the remainder (40% to 30%). This primary agent can have a viscosity of 200 mPa·s and a specific gravity of 1.2, and is contained at 100 parts by weight in both formula A and formula B.
A mixture of a polyol component, a powder and a plasticizing agent component can be used for the curing agent. The polyol component undergoes a urethanation reaction with the primary agent, the powder serves to enhance the specific gravity of the chemical agents and increase their amount, and the plasticizing agent component is for lowering the viscosity of the chemical agents.
In an exemplary embodiment, a polyester polyol obtained from castor oil (also simply referred to as castor oil) can be used for the polyol component. Castor oil can be obtained from the seeds of a castor oil plant, and is an ester of fatty acids and glycerin. In castor oil, the majority (about 90%) of the fatty acids can include ricinoleic acid having the structure shown in
As shown in
In the example shown in
In an exemplary embodiment, calcium carbonate can be used for the powder. More specifically, NS200 (trade name) manufactured by Nitto Funka Kogyo Co., Ltd. can be used for the powder. This calcium carbonate is contained in an amount of 200 parts by weight in the chemical agent in both formula A and formula B.
Furthermore, a powder other than calcium carbonate can be used for the powder provided it can be incorporated in urethane. Examples of powders that can be used include carbon black, clay, talc, silica, titanium oxide, unslaked lime, kaolin, zeolite, diatomaceous earth, aluminum sulfate, barium sulfate and bentonite, and these can be used alone or as a mixture thereof.
In an exemplary embodiment, diisononyl adipate (DINA) manufactured by Taoka Chemical Co., Ltd. is used for the plasticizing agent component. An exemplary reason for selecting diisononyl adipate for the plasticizing agent component is that it can be highly compatible with the curing agent (Crude MDI: M-200) and is resistant to reacting with the curing agent. There can be a difference in the contents of this plasticizing agent in the chemical agent between formula A and formula B. For example, this plasticizing agent component can be contained in an amount of 200 parts by weight in formula A and in an amount of 1200 parts by weight in formula B.
Furthermore, although this plasticizing agent component can also be added to the primary agent, it can be added to the curing agent in an exemplary embodiment. This can avoid a situation in which moisture contained in the plasticizing agent component ends up reacting with the Crude MDI composing the primary agent.
In addition, there are numerous types of plasticizing agents that can be used, including phthalic acid esters, adipic acid esters, phosphoric acid esters and trimellitic acid esters, and a plasticizing agent other than diisononyl adipate can be used. For example, exemplary plasticizing agents such as diethylhexyl phthalate (DOP), diisononyl phthalate (DINP) or dioctyl adipate (DOA) can also be used.
The curing agent of formula A can have a viscosity of 67 mPa·s and specific gravity of 1.0, while the curing agent of formula B can have a specific gravity of 67 mPa·s and viscosity of 1.0. The mixing ratio of the primary agent to the curing agent in the waterproofing agent of formula A can be 1/10. Namely, 100 parts by weight of the primary agent can be mixed with 1000 parts by weight of the curing agent. In addition, the mixing ratio of the primary agent to the curing agent in the waterproofing agent of formula A can be 1/20. Namely, 100 parts by weight of the primary agent can be mixed with 2000 parts by weight of the curing agent. The viscosity of the waterproofing agent of formula A at normal temperatures immediately after mixing can be 524 mPa·s, while the viscosity of the waterproofing agent of formula B at normal temperatures can be 79 mPa·s.
Next, an explanation is provided of an exemplary waterproof sheet repair test using the aforementioned waterproofing agents (formula A and formula B). In this repair test, as shown in
Two exemplary test yards 4 were prepared. One of the test yards was used for Case 1 and Case 2, while the other test yard was used for Case 3. For the sake of convenience, in the following explanations, the test yard used for Cases 1 and 2 is referred to as test yard 4A, while the test yard used for Case 3 is referred to as test yard 4B.
Subsequently, water was injected into each of the test yards 4A and 4B, and water was allowed to seep from a defect 5 provided in advance in the upper layer waterproof sheet 1U on top. After inserting a rod 6 into the fill soil 3 from above the defect 5, a waterproofing agent 7 was injected into the defect 5 from the distal end of the rod 6. Whether or not the defect 5 was sealed with the waterproofing agent 7 was confirmed through the electrically conductive mat 2 arranged between the waterproof sheets 1. The following provides an description thereof.
As shown in
In Cases 1 and 2, leakage current values are measured with a detection system that electrically detects locations of water seepage, and this measurement was used to verify whether it was possible to confirm completion of repairs. In addition, in Case 3, one electrode each was arranged on the side of the upper layer protective sheet 1U and the side of the lower layer protective sheet 1D, conduction current was measured after injecting the waterproofing agent 7 to verify whether or not completion of repair can be confirmed even in the case the protective mat 8 is interposed between the protective sheet 1 and the soil.
In this exemplary repair test, the test yard 4 is first prepared (S1). Here, as shown in
Once the depression 9 has been formed, the lower layer waterproof sheet 1D is spread out so as to cover the depression 9 (S2). Namely, as shown in
Once the lower layer waterproof sheet 1D has been spread, the electrically conductive mat 2 is spread out (S3). The electrically conductive mat 2 has electrodes attached to a rectangular non-woven fabric 2a. Two types of electrodes are provided including measuring electrodes 2a and current electrodes. The measuring electrodes 2b are electrodes for measuring resistance values, and in the electrically conductive mat 2 used for Cases 1 and 2, a large number of the measuring electrodes 2b are arranged at intervals in the planar direction on the upper surface of the non-woven fabric 2a as shown in
Once the electrically conductive mat 2 has been spread out, the upper layer waterproof sheet 1U is spread over this electrically conductive mat 2 (S4). The upper layer waterproof sheet 1U used here has been damaged in advance. The defects 5 are, for example, L-shaped cuts measuring 3 cm×3 cm. There are two defects 5 in the upper layer waterproof sheet 1U for Cases 1 and 2 as shown in
Once the upper layer waterproof sheet 1U has been spread out, the protective mat 8 is spread out only for the test yard 4B for Case 3 (S5). As shown in
Next, the fill soil 3 is prepared (S6). The fill soil 3 is respectively prepared on the upper layer waterproof sheet 1U with respect to the test yard 4A and on the protective mat 8 with respect to the test yard 4B. The fill soil 3 of the test yard 4A is shown in
Once the fill soil 3 has been prepared, water is added (S7) and resistance values and the like are confirmed (S8). Addition of water is carried out by injecting water into the fill soil 3 to the level indicated by the dotted line of reference symbol L1 shown in
In this exemplary repair test, since the defects 5 are provided in the upper layer waterproof sheet 1U, water penetrates to the electrically conductive mat 2 through the defects 5, and the measuring electrodes 2b and current electrodes are connected electrically (for example, leakage current flows). With respect to the test yard 4A, since a plurality of measuring electrodes 2b are arranged therein, the location where seepage is occurring (for example, the locations of the defects 5) can be detected by measuring leakage current values for each measuring electrode 2b.
Once resistance values and the like have been confirmed, the waterproofing agent 7 is injected (S9). When injecting the waterproofing agent 7, an insertion hole for inserting the rod 6 is first formed extending vertically downward from the upper surface of the fill soil 3. As shown in
In this repair test, with respect to Case 1, the waterproofing agent 7 is injected for one of the defects 5 in the test yard 4A as shown in
The waterproofing agent 7 that has been pumped with the pump 10 is injected through a tube 11 (see
Once the waterproofing agent 7 has been injected, resistance values and the like are confirmed (S10). This confirmation procedure is carried out in the same manner as the confirmation procedure of step S8. Here,
In Case 1, the resistance value rapidly increased from 2500Ω immediately after injecting the waterproofing agent 7 of formula A, and reached 24000Ω 3 minutes after injection. Although the resistance value subsequently decreased slightly, it stabilized at about 22000Ω.
In Case 2, the resistance value rapidly decreased to about 2200Ω immediately after injecting the waterproofing agent 7 of formula B. However, similar to injection of the waterproofing agent 7 in Case 1, the resistance value immediately began to increase rapidly, reaching about 16000Ω 1.5 minutes after injection in Case 2. The resistance value subsequently stabilized at 18000Ω.
Furthermore, the rapid decrease in the resistance value that occurred immediately after injection of the waterproofing agent 7 in Case 2 is thought to have been caused by an increase in size of the defect 5 of Case 2 due to injection pressure as a result of the pressure applied during injection. Namely, the resistance value was thought to have increased over time since a larger defect 5 was sealed by the waterproofing agent 7 of Case 2.
Furthermore, in the repair tests of Case 1 and Case 2, electrical resistance values were lower than in the repair test of Case 3. This was determined to be the result of one of the measuring electrodes 2b having moved directly beneath the defect 5 at the stage of preparing the fill soil 3, thereby obstructing closure of the defect 5.
When the waterproofing agent 7 of formula B was injected in Case 3, the resistance value gradually increased from 10000Ω, and reached 100000Ω after 2 hours had passed since injection of the waterproofing agent 7. The reason for this increase in the resistance value is thought to be the result of the defect 5 being sealed as the waterproofing agent 7 gradually penetrated to the defect 5 in the waterproof sheet 1, thereby inhibiting the flow of current.
In addition, leakage current values were measured for each measuring electrode 2b in Cases 1 and 2.
The defect 5 indicated with reference symbol X1 in
In
Once resistance values and leakage current values have been confirmed, the injection status of the waterproofing agent 7 is confirmed (S11). This confirmation procedure was carried out by removing the fill soil 3 after 16 days had passed since injection of the waterproofing agent 7.
The fill soil 3 in the test yard 4A was dismantled as shown in
On the basis of these findings, the waterproofing agent 7 was able to be confirmed to have entered the defect 5 of the upper layer waterproof sheet 1U and repaired the defect 5 in the test yard 4A. Namely, the waterproofing agent 7 that filled the defect 5 was able to be confirmed to have reached the electrically conductive mat 2 and sealed the defect 5.
The fill soil 3 in the test yard 4B was dismantled as shown in
On the basis of these findings, the waterproofing agent 7 was able to be confirmed to have sealed the defect 5 in the upper layer waterproof sheet 1U and reached the electrically conductive mat 2 in the test yard 4B. For example, the defect 5 in the waterproof sheet 1 was able to be confirmed to be able to be sealed even if the protective mat 8 is interposed between the protective sheet 1U and the fill soil 3.
In this manner, the waterproofing agent 7 of the exemplary embodiment has the property of sealing the defect 5 by penetrating into the protective mat 8 composed of a non-woven fabric. Consequently, as shown in
As has been previously explained, since an exemplary embodiment uses a urethane-based waterproofing agent obtained by mixing a primary agent containing an isocyanate component and a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, the viscosity of the waterproofing agent does not become excessively high even at normal temperatures, and the waterproofing agent can be used to repair a waterproof sheet. As a result, handling is facilitated without requiring warming.
In addition, since an exemplary waterproof sheet repair method includes a step (S8) for acquiring an electrical status through the electrically conductive mat 2 arranged between the layered waterproof sheets 1U and 1D, and a step (S9) for injecting the urethane-based waterproofing agent 7, obtained by mixing a primary agent containing an isocyanate component and a curing agent containing a polyester polyol obtained from castor oil and a plasticizing agent component, from the top side of the upper layer waterproof sheet 1U, and sealing the defect 5 in the upper layer waterproof sheet 1U with the waterproofing agent 7, the viscosity of the waterproofing agent 7 again does not become excessively high even at normal temperatures, and the waterproofing agent 7 can be used to repair the waterproof sheet.
In addition, since an exemplary urethane-based waterproofing agent uses a mixture of polymethylene polyphenyl polyisocyanate and 4,4′-diphenylmethane diisocyanate for the primary agent and diisononyl adipate for the plasticizing agent component, the viscosity of the waterproofing agent can be held to a low level even at normal temperatures.
In addition, since an exemplary urethane-based waterproofing agent contains a powder in the curing agent, the specific gravity of the waterproofing agent can be enhanced. As a result, the waterproofing agent can rapidly reach the defect 5.
Furthermore, the exemplary embodiment as explained above is intended to facilitate understanding of exemplary aspects, and the presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The disclosed embodiments can be altered or modified within an appropriate range. For example, a waterproof structure may be an industrial waste disposal site or a man-made pond. In addition, for example, the powder may be excluded from the curing agent provided the waterproofing agent has sufficient specific gravity.
An exemplary aspect relates to, for example, a waterproofing agent for a waterproof sheet that can be handled easily and does not require warming, and to a waterproof sheet repair method that uses this waterproofing agent.
It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
1U Upper layer waterproof sheet
1L Lower layer waterproof sheet
2 Electrically conductive mat
2
a Non-woven fabric
2
b Measuring electrode
3 Fill soil
4A,4B Test yard
5 Defect
6 Rod
7 Waterproofing agent
8 Protective mat
9 Depression
10 Pump
11 Tube
12 Non-woven fabric
13 Waterproof sheet
14 Permanent fixture
Number | Date | Country | Kind |
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2010-123565 | May 2010 | JP | national |
This application claims priority as a continuation application under 35 U.S.C. §120 to PCT/JP2011/062207, which was filed as an International Application on May 27, 2011 designating the U.S., and which claims priority to Japanese Application No. 2010-123565 filed in Japan on May 28, 2010. The entire contents of these applications are hereby incorporated by reference in their entireties.
Number | Date | Country | |
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Parent | PCT/JP2011/062207 | May 2011 | US |
Child | 13687525 | US |