Waterproof membrane and method for producing the same

Abstract

The present invention aims to provide a waterproof membrane that is applicable to parking lots and exhibits excellent weather resistance and abrasion resistance without the application of a topcoat. [Solution] A waterproof membrane that is placed on and exposed on the floor of a parking lot having a parking area for parking vehicles, wherein the waterproof membrane consists of a primer layer, a waterproof layer, and an anti-slip layer laminated in that order on the floor, with the anti-slip layer being the outermost layer of the waterproof membrane, and the anti-slip layer being composed of a urethane composition and aggregate, wherein the urethane composition is a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, and the urethane prepolymer is formed from a polyisocyanate compound and a polyol containing polyoxyalkylene polyol and butanediol, with the molar equivalent ratio of butanediol to polyoxyalkylene polyol being 60:40 to 75:25, and a method for producing the same.

Description

[Technical Field] 【0001】 The present invention relates to a waterproof membrane and a method for producing the same. [Background technology] 【0002】 In recent years, the rooftops, middle floors, or basements of large buildings such as commercial facilities and hospitals have been used as parking lots. Such parking lots are typically constructed on top of the aforementioned building, for example, using concrete as the floor. When used as a parking lot, it is common practice to apply a urethane waterproof coating to the concrete or other floor, and then apply a topcoat with weather resistance and abrasion resistance over the entire urethane waterproof coating. Conventionally, materials used for such topcoats include, for example, acrylic urethane-based topcoats (see, for example, Patent Document 1). [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] Japanese Patent Publication No. 2007-720 [Overview of the project] [Problems that the invention aims to solve] 【0004】 However, in acrylic urethane topcoats, a large amount of solvent with a strong odor is usually used to dissolve the acrylic polyol, which is the raw material for acrylic urethane, into the topcoat composition. Therefore, from an environmental and hygiene perspective, there is a need for construction methods that do not use a topcoat on top of the urethane waterproof coating material. In addition, by not using a topcoat, the number of steps required for applying the topcoat can be reduced. On the other hand, as mentioned above, a topcoat can impart weather resistance and abrasion resistance to the waterproofing material. Therefore, if a topcoat is not used, it becomes necessary to improve the weather resistance and abrasion resistance of the waterproofing material itself. 【0005】 The present invention aims to provide a waterproof membrane and a method for producing the same that can be applied to parking lots and have excellent weather resistance and abrasion resistance without the application of a topcoat. [Means for solving the problem] 【0006】 As a result of diligent research to solve the above problems, the inventors of the present invention have found that the above problems can be solved by having a waterproof membrane, which is placed on the floor of a parking lot having a parking area for parking vehicles and is exposed to the elements, and by having the outermost anti-slip layer composed of a urethane composition and aggregate, and by having the polyol that forms the urethane prepolymer contained in the urethane composition contain butanediol and polyoxyalkylenediol, and by having the molar equivalent ratio of butanediol and polyoxyalkylenediol within a predetermined range, thereby leading to the present invention. The present invention is based on the above findings, and specifically solves the above problems with the following configuration. 【0007】 [1] A waterproof membrane that is placed on and exposed on the floor of a parking area for parking vehicles, wherein the waterproof membrane is laminated on the floor in the order of a primer layer, a waterproof layer, and an anti-slip layer, the anti-slip layer being the outermost layer of the waterproof membrane, the anti-slip layer being composed of a urethane composition and aggregate, the urethane composition being a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, the urethane prepolymer being formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of butanediol to polyoxyalkylene polyol (butanediol:polyoxyalkylene polyol) being 60:40 to 75:25. [2] The waterproof membrane according to [1], wherein the isocyanate group content of the urethane prepolymer is 6.0 to 9.0% by mass of the urethane prepolymer. [3] The waterproof membrane according to [1] or [2], wherein the parking lot further has a driving area for the vehicle to drive, and the parking area and the driving area are integrated to form the floor. [4] A production method for producing a waterproof membrane that is disposed and used in an exposed manner on the floor of a parking lot having a parking area for parking a vehicle. The method includes the step of laminating a primer layer, a waterproof layer, and an anti-slip layer on the floor in this order. The anti-slip layer is the outermost layer of the waterproof membrane, and the anti-slip layer is composed of a urethane-based composition and an aggregate. The urethane-based composition is a one-component urethane-based composition containing a urethane prepolymer having an isocyanate group and a latent curing agent. The urethane prepolymer is formed by a polyisocyanate compound having a plurality of isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of butanediol to polyoxyalkylene polyol (butanediol: polyoxyalkylene polyol) is 60:40 to 75:25. 【Effects of the Invention】 【0008】 According to the present invention, it is possible to provide a waterproof membrane with excellent weather resistance and abrasion resistance and a production method thereof, which are applied to a parking lot without applying a top coat. 【Brief Description of the Drawings】 【0009】 [Figure 1] FIG. 1 is a photograph showing an example of a parking lot having a parking area for parking a vehicle. [Figure 2] FIG. 2 is a photograph showing an example when a slope connecting each floor of a building serves as a driving area for a vehicle. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an example of the floor of a parking lot and the waterproof membrane of the present invention disposed thereon. ] 【Modes for Carrying Out the Invention】 【0010】 Hereinafter, the present invention will be described in detail. The following description of the constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. In this specification, when using a certain component, unless otherwise specified, that component may be used alone or in combination of two or more types. In this specification, if two or more components are present, the "content" of those components means the total content of those two or more components unless otherwise specified. In this specification, the method of producing a certain component is not limited unless otherwise specified. Examples include conventionally known methods. In this specification, when applied to a parking lot without the application of a topcoat, the fact that at least one of the weather resistance and abrasion resistance of the waterproof membrane of the present invention is superior is also referred to as "the effects of the present invention are superior." In this specification, the urethane prepolymer contained in the urethane composition that forms the anti-slip layer of the waterproof membrane of the present invention is also referred to as the "specific urethane prepolymer." In this specification, the urethane-based composition that forms the anti-slip layer of the waterproof membrane of the present invention is also referred to as the "specific urethane-based composition." 【0011】 [Waterproof membrane after processing] The waterproof membrane of the present invention will be described in detail below. The waterproof membrane of the present invention is A waterproof membrane is provided for use on the floor of a parking lot having a parking area for parking vehicles, wherein the waterproof membrane is laminated on the floor in the order of a primer layer, a waterproof layer, and an anti-slip layer, the anti-slip layer being the outermost layer of the waterproof membrane, the anti-slip layer being composed of a urethane composition and aggregate, the urethane composition being a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, the urethane prepolymer being formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of butanediol to polyoxyalkylene polyol (butanediol:polyoxyalkylene polyol) being 60:40 to 75:25. 【0012】 The reason why the waterproof membrane of the present invention can achieve the above effects is not clear, but the inventors speculate that the mechanism of the present invention is as follows. In the waterproof membrane of the present invention, the anti-slip layer is the outermost layer of the waterproof membrane. Since the waterproof membrane of the present invention is placed on the floor of the parking lot and used in an exposed state, at least the anti-slip layer is exposed in the waterproof membrane of the present invention. In other words, there is no topcoat on the waterproof membrane of the present invention. For this reason, the anti-slip layer needs the weather resistance and abrasion resistance that a topcoat normally possesses. In the present invention, the anti-slip layer is formed by the urethane composition containing the urethane prepolymer, and the polyol forming the urethane prepolymer contains butanediol and polyoxyalkylene polyol. It is believed that by having the molar equivalent ratio of butanediol to polyoxyalkylene polyol within a predetermined range, the crosslinking of the cured product obtained from the urethane composition becomes denser, thereby improving the weather resistance and abrasion resistance of the anti-slip layer in the waterproof film of the present invention. Furthermore, cases where the effect is obtained by mechanisms other than those described above are also included within the scope of the present invention. 【0013】 [parking] The parking lot in which the waterproof membrane of the present invention is installed can be any parking lot having a parking area for parking vehicles. Examples of parking facilities include those located on the rooftops, middle floors, or underground of large buildings such as commercial facilities and hospitals. 【0014】 [Parking area] In this invention, a parking area is an area for parking vehicles. In this invention, a parking area is a broad concept that includes an area where vehicles can be parked (for example, the floor in the case where a parking lot occupies the entire floor of a large building), and a single parking space for parking one vehicle. 【0015】 (Driving area) The above-mentioned parking lot may further have a driving area for vehicles to travel on. Examples of the above-mentioned driving area include at least one or all of the area surrounding the above-mentioned parking area, and ramps connecting each floor of the building. If the above-mentioned parking area further includes a driving area for vehicles to travel on, the parking area and the driving area may be integrated to form the floor (substrate) of the parking area. Examples of cases where the parking area and the driving area are integrated include cases where the parking area and the driving area are integrated to form a parking area on the rooftop or on each floor of a building, and cases where, in addition to the rooftop or on-floor parking area where the parking area and driving area are integrated as described above, a ramp connecting each floor of the building is connected as a driving area, and these are integrated. The floor (substrate) of the parking lot may be made of concrete, mortar, or the like. 【0016】 [Waterproof membrane] The waterproof membrane of the present invention is a waterproof membrane that is placed on and exposed on the floor of the parking lot. The waterproof membrane of the present invention can waterproof the floor (substrate) of the parking lot. 【0017】 [Placement] The waterproof membrane of the present invention may be placed in the parking area of ​​the parking lot, and if the parking lot further has a driving area, the waterproof membrane of the present invention may be placed in both the parking area and the driving area. Alternatively, the waterproof membrane of the present invention may be placed over the entire floor of the parking lot having a parking area. 【0018】 [Exposure] The waterproof membrane of the present invention is placed on the floor of the parking lot and is exposed. In the present invention, exposure of the waterproof membrane of the present invention means that there is no topcoat on the waterproof membrane of the present invention (that the waterproof membrane of the present invention is not covered by a topcoat). Therefore, in the present invention, the anti-slip layer becomes the outermost layer of the waterproof layer of the present invention. In other words, in the waterproof membrane of the present invention, at least the anti-slip layer is directly exposed to, for example, sunlight, rain, and contact with tires. 【0019】 The above-mentioned parking lot will be described below using the attached drawings. Note that the present invention is not limited to the attached drawings. (Figure 1) Figure 1 is a photograph showing an example of a parking lot with parking areas for parking vehicles. In Figure 1, parking lot 1 has multiple parking areas 11, each accommodating one vehicle. Adjacent parking areas 11 are separated by lines 13. In addition, parking lot 1 has a driving area 15 in addition to the parking area 11. The parking area 11 and the driving area 15 are integrated to form parking lot 1. Arrows 17 indicating the direction of vehicle travel are painted on the driving area 5. The waterproof membrane of the present invention is already laid over the entire floor surface of parking lot 1, and lines 13, arrows 17, etc. are applied on top of the waterproof membrane of the present invention. In Figure 1, the waterproof membrane of the present invention (specifically the anti-slip layer) is exposed in the areas other than those to which lines 13, arrows 17, etc. are applied and the wheel stops. 【0020】 (Figure 2) Figure 2 is a photograph illustrating an example where the ramps connecting each floor of a building are used as vehicle access areas. In Figure 2, the ramp 25 connects to the rooftop or floor-level parking area, which integrates the parking and driving areas, as a driving area, and further connects each floor of the building. The ramp 25 slopes downward from the foreground of the photograph to the left in the background. The ramp 25 has a driving area 21 and collision prevention poles 27, and the driving area 21 is demarcated by lines 23. The waterproof membrane of the present invention is already laid over the entire floor of the slope 25, and the line 23 is applied on top of the waterproof membrane of the present invention. In the slope 25 (floor), the waterproof membrane of the present invention (more specifically the anti-slip layer) is exposed in areas other than those where the line 23 and pole 27 are installed. 【0021】 [Lamination of waterproof membrane] The waterproof membrane of the present invention is constructed by laminating a primer layer, a waterproof layer, and an anti-slip layer in that order on top of the floor (substrate) of a parking lot. 【0022】 The waterproof membrane of the present invention (particularly the lamination of the waterproof membrane of the present invention) will be described below with reference to the attached drawings. However, the waterproof membrane of the present invention is not limited to the attached drawings. (Figure 3) Figure 3 is a schematic cross-sectional view showing an example of a parking lot floor and the waterproof membrane of the present invention placed thereon. In Figure 3, a waterproof membrane 30 is placed on the floor 31 of a parking lot with a parking area for parking vehicles. The waterproof membrane 30 is exposed. The waterproof membrane 30 is constructed by laminating a primer layer 35, a waterproof layer 37, and an anti-slip layer 39 on the floor 31 in that order. The anti-slip layer 39 is the outermost layer of the waterproof membrane 30. 【0023】 Furthermore, lines indicating parking areas, the direction a vehicle should travel, and stopping positions can be partially displayed on the waterproof membrane of the present invention. Furthermore, the waterproof membrane of the present invention may be placed on parts of the parking lot other than the floor, for example, on the walls. 【0024】 The following describes each layer of the waterproof membrane of the present invention. [Primer layer] The waterproof membrane of the present invention has a primer layer. The primer layer can improve the adhesion between the parking lot floor (substrate) and the waterproof layer. The thickness of the primer layer can be, for example, 0.01 to 1 mm. The primer layer may be, for example, an epoxy resin primer or a urethane resin primer. A commercially available material used to form the primer layer is, for example, Primer PW-F for parking lots (manufactured by Sika Japan Co., Ltd.). 【0025】 [Waterproof layer] The waterproof membrane of the present invention has a waterproof layer. The waterproof layer is placed between the primer layer and the anti-slip layer described later. The waterproof layer can waterproof the floor (substrate) of a parking lot. The thickness of the waterproof layer may be, for example, 0.5 to 6 mm, and is preferably 1 to 3 mm. The waterproof layer may be a coating waterproofing material made of, for example, a polyurethane resin, epoxy resin, polyester resin, vinyl ester resin, or methyl methacrylate resin. The waterproof layer is preferably a polyurethane resin, and more preferably a polyurethane resin formed from a one-component urethane composition. Examples of commercially available materials used to form a waterproof layer include Evercoat Zero-1H for parking lots and Plamax 450P (ND) (both manufactured by Sika Japan). The materials used to form the waterproof layer do not include the specific urethane-based composition used to form the anti-slip layer described later. 【0026】 [Anti-slip layer] The waterproof membrane of the present invention has an anti-slip layer. In the present invention, the anti-slip layer is the outermost layer of the waterproof membrane of the present invention. Therefore, the waterproof membrane of the present invention does not have a topcoat on top of the anti-slip layer, which is typically found on general coating waterproofing materials. Because the urethane-based composition constituting the anti-slip layer is a specific urethane-based composition, the waterproof membrane of the present invention has excellent abrasion resistance and weather resistance even without a topcoat. As described above, the anti-slip layer has excellent abrasion resistance, thus protecting the waterproof layer from wear caused by vehicle traffic. Furthermore, the anti-slip layer can prevent vehicles from slipping in parking lots. The thickness of the anti-slip layer can be, for example, 0.05 to 8 mm, but from the viewpoint of achieving superior effects of the present invention, it is preferably 0.1 to 3 mm. The thickness of the anti-slip layer refers to the distance from the surface of the anti-slip layer that contacts the waterproof layer, excluding the protrusions caused by the aggregate, to the flat surface of the anti-slip layer (i.e., excluding the height of the portion that protrudes from the surface of the anti-slip layer due to the aggregate). 【0027】 In the present invention, the anti-slip layer is composed of a specific urethane-based composition and aggregate. The specific urethane-based composition will be described later. 【0028】 [aggregate] In this invention, the anti-slip layer includes aggregate. The aggregate included in the anti-slip layer may be, for example, natural silicate materials such as silica sand, minerals (such as basalt), river sand, or ceramics. The average particle size of the aggregate can be, for example, 0.1 mm to 2 mm, and more preferably 0.2 mm to 1 mm. The average particle size can be measured by methods such as laser diffraction / scattering, and can be measured using, for example, the SALD-2000J particle size distribution analyzer manufactured by Shimadzu Corporation. (Amount of aggregate) The amount of aggregate can be 10 to 200 parts by mass per 100 parts by mass of the solid content (cured product) of the specified urethane composition. Here, the solid content of the specified urethane composition refers to the entire composition if it does not contain a solvent, or the remainder after subtracting the amount of solvent from the total amount of the specified urethane composition if it contains a solvent. One preferred embodiment is that the aggregate is dispersed in the solid content (cured product) of a specific urethane-based composition. 【0029】 (Method for producing a waterproof membrane according to the present invention) Examples of the production method (manufacturing method) for the waterproof membrane of the present invention include: A production method for producing a waterproof membrane to be placed on and exposed on the floor of a parking lot having a parking area for parking vehicles, the production method comprising the step of laminating a primer layer, a waterproof layer, and an anti-slip layer on the floor in that order, wherein the anti-slip layer is the outermost layer of the waterproof membrane, the anti-slip layer is composed of a urethane composition and aggregate, the urethane composition is a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, the urethane prepolymer is formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of butanediol to polyoxyalkylene polyol (butanediol:polyoxyalkylene polyol) is 60:40 to 75:25. 【0030】 More specifically, a method for producing (manufacturing) the waterproof membrane of the present invention includes, for example, a step 1 of applying a material used to form a primer layer to the entire surface of a parking lot floor (substrate) and drying it to form a primer layer; a step 2 of applying a material used to form a waterproof layer to the entire surface of the primer layer and curing it to form a waterproof layer; a step 3 of applying a specific urethane-based composition to the entire surface of the waterproof layer; a step 4 of scattering aggregate on the specific urethane-based composition applied in step 3 before it hardens, and then curing the specific urethane-based composition; and a step 5 of applying the specific urethane-based composition again on the aggregate, and further curing the specific urethane-based composition to form an anti-slip layer and obtain the waterproof membrane of the present invention. 【0031】 ·Process 1 Step 1 is the process of applying a material used to form a primer layer to the entire surface of the parking lot floor (substrate), and allowing it to dry to form the primer layer. Methods for applying the above-mentioned material include application by roller, brush, etc., and spraying by spray gun. The amount of the above material to be applied (amount applied per application; the same applies to the amount applied hereafter) is, for example, 0.15 to 0.2 kg / m². 2 It can be done this way. In step 1, the above material may be applied once or multiple times. The drying time for the above materials can range from 1 to 24 hours, depending on the size of the parking lot, the season, and the outdoor temperature. 【0032】 ·Process 2 Step 2 is the process of applying a material used to form a waterproof layer to the entire surface of the primer layer and curing it to form a waterproof layer. Methods for applying the above-mentioned material include application by roller, brush, etc., and spraying by spray gun. The amount of the above material to be applied is, for example, 1.5 to 3.0 kg / m². 2 It can be done this way. In step 2, the above material may be applied once or multiple times. The curing time for the above materials can range from 1 to 24 hours, depending on the size of the parking lot, the season, and the outdoor temperature. 【0033】 ·Process 3 Step 3 is the step of applying a specific urethane-based composition to the entire surface of the waterproof layer. Methods for applying specific urethane compositions include, for example, application by roller, brush, or the like. The application rate of the specific urethane composition is, for example, 0.1 to 1.0 kg / m². 2 It can be done this way. In step 3, the specific urethane composition may be applied once or multiple times. 【0034】 ·Process 4 Step 4 is a step in which aggregate is scattered on top of the specific urethane composition applied in Step 3 before it hardens, and then the specific urethane composition is cured. The method for scattering the aggregate may be, for example, a conventionally known method. The amount of aggregate to be scattered can be, for example, an amount that corresponds to the amount of aggregate per 100 parts by mass of the solid content (cured product) of the specified urethane composition described above. In step 4, the curing period for the specific urethane composition after scattering the aggregate can be, for example, 1 to 24 hours, depending on the size of the parking lot, the season, and the outdoor temperature. 【0035】 ·Process 5 Step 5 is a step in which the specific urethane composition is applied again on top of the aggregate, and then the specific urethane composition is cured to form an anti-slip layer and obtain the waterproof membrane of the present invention. Methods for applying the specific urethane composition in step 5 include, for example, application by roller, brush, etc. In step 5, the curing period for the specific urethane composition can be, for example, 1 to 24 hours, depending on the size of the parking lot, the season, and the outdoor temperature. In this invention, the step of applying a topcoat is omitted after step 5. 【0036】 [Urethane-based composition] In the present invention, the urethane-based composition (specific urethane-based composition) constituting the anti-slip agent will be described below. In the present invention, the specific urethane composition is a one-component urethane composition containing a urethane prepolymer having an isocyanate group and a latent curing agent. 【0037】 [Urethane prepolymer (specific urethane prepolymer)] The specific urethane composition contains a urethane prepolymer having an isocyanate group (specific urethane prepolymer). 【0038】 One preferred embodiment of the specific urethane prepolymer is that it has the above-mentioned isocyanate group at its terminal end. 【0039】 In the present invention, the specific urethane prepolymer is formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol. 【0040】 [Polyisocyanate compounds] The polyisocyanate compound used to form a specific urethane prepolymer is not particularly limited as long as it is a compound having multiple isocyanate groups per molecule. Examples include xylylene diisocyanate (XDI), hexamethylene diisocyanate, and isophorone diisocyanate (IPDI). The polyisocyanate compound used to form the specific urethane prepolymer preferably contains an aliphatic diisocyanate, and more preferably contains an isophorone diisocyanate, from the viewpoint of achieving superior effects of the present invention. 【0041】 [Polyol] In the present invention, the polyol used to form a specific urethane prepolymer includes butanediol and polyoxyalkylene polyol. Polyols refer to compounds that have multiple hydroxyl groups per molecule. 【0042】 [Butanediol] In the present invention, the butanediol used to form the specific urethane prepolymer preferably contains 1,4-butanediol, from the viewpoint of achieving superior effects of the present invention. 【0043】 [Polyoxyalkylene polyol] In the present invention, the polyoxyalkylene polyol used to form a specific urethane prepolymer refers to a polyoxyalkylene compound having multiple hydroxyl groups per molecule. Examples of oxyalkylene groups that constitute polyoxyalkylene polyols include oxyethylene groups, oxypropylene groups, and combinations thereof. From the viewpoint of achieving superior effects of the present invention, the polyoxyalkylene polyol preferably contains polyoxyalkylenediol, and more preferably contains polyoxypropylenediol. The number-average molecular weight of the polyoxyalkylene polyol is preferably 1500 to 5000, and more preferably 1800 to 2500, from the viewpoint of achieving superior effects of the present invention. In this specification, the number-average molecular weight of a compound can be obtained in terms of polystyrene equivalent by gel permeation chromatography. 【0044】 [Molar equivalent ratio of butanediol and polyoxyalkylene polyol] In the present invention, the molar equivalent ratio (butanediol:polyoxyalkylene polyol) of the butanediol and polyoxyalkylene polyol used to form a specific urethane prepolymer is 60:40 to 75:25. Because the above molar equivalent ratio is within the above range, the waterproof membrane of the present invention has excellent abrasion resistance and weather resistance. From the viewpoint of achieving superior effects of the present invention and making the resulting anti-slip film (and consequently the waterproof film) less prone to cracking, the above molar equivalent ratio is preferably 65:35 to 75:25. 【0045】 The polyol may further contain polyols other than the above-mentioned butanediol and polyoxyalkylene polyol (other polyols). Examples of other polyols include polyester polyols. The polyester polyol is not particularly limited. 【0046】 From the viewpoint of achieving superior effects of the present invention, the polyol preferably contains the above-mentioned butanediol and the above-mentioned polyoxyalkylene polyol in a total amount of 50 to 100% by mass, and more preferably 100% by mass, of the total amount of polyol. 【0047】 (Isocyanate group content of specific urethane prepolymers) From the viewpoint of achieving superior effects of the present invention, the isocyanate group content of the specific urethane prepolymer is preferably 6.0 to 9.0% by mass, and more preferably 7.0 to 8.0% by mass. 【0048】 (Content of specific urethane prepolymers) From the viewpoint of achieving superior effects of the present invention, the content of the specific urethane prepolymer is preferably 30 to 50% by mass of the total amount of the specific urethane composition. 【0049】 (Method for preparing specific urethane prepolymers) The method for preparing the specific urethane prepolymer is not particularly limited, but for example, a solution is prepared by weighing and mixing 1,4-butanediol and polypropylene glycol with a number-average molecular weight of 2000 as a polyoxyalkylene polyol in a predetermined molar equivalent ratio. Taking into account the amount of water in the polypropylene glycol, isophorone diisocyanate (IPDI) (polyisocyanate) is added to the solution so that the molar equivalent ratio (NCO / OH) of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the 1,4-butanediol and polypropylene glycol is greater than 1.0 and less than or equal to 3.0 to form a liquid mixture. Then, the liquid mixture is heated while stirring, a catalyst is added in an amount of 0.01 to 1% by mass of the total liquid mixture, and the reaction is carried out under conditions of 40 to 110°C to produce the specific urethane prepolymer. In this specification, the above molar equivalent ratio (NCO / OH) represents the molar equivalent ratio of isocyanate groups in a polyisocyanate compound to hydroxyl groups in a polyol containing butanediol and polyoxyalkylene polyol used in the preparation of a specific urethane prepolymer. Regarding the molar equivalent of hydroxyl groups in the above molar equivalent ratio (NCO / OH), as described above, the amount of water contained in the polyoxyalkylene polyol such as polypropylene glycol may or may not be added to the total molar equivalent of the hydroxyl groups. 【0050】 The catalysts that can be used when preparing specific urethane prepolymers are not particularly limited as long as they are compounds that can promote the reaction between the isocyanate group and the polyol. Examples include organotin compounds (tin catalysts) such as dibutyltin diacetate, dibutyltin dilaurate, and dibutyltin bis(3-mercaptopropionate ethoxybutyl ester) salt; organotitanium compounds such as titanic acid, tetraisopropyl titanate, tetra-n-butyl titanate, polyhydroxytitanium stearate, and titanium acetylacetonate; and tertiary amine compounds such as triethylenediamine, N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, triethylamine, and N,N-dimethylaminoethanol. 【0051】 [Latent curing agent] In the present invention, the specific urethane composition contains a latent curing agent. The latent curing agent can be hydrolyzed upon contact with moisture (e.g., humidity in the air) to produce a compound having a functional group containing an active hydrogen group. A specific urethane-based composition can become a one-component urethane-based composition by containing a latent curing agent. 【0052】 The latent curing agent preferably contains a compound having an oxazolidine ring, and more preferably contains a bis-oxazolidine compound in which two oxazolidine rings are crosslinked by a linking group having a urethane bond, from the viewpoint of achieving superior effects of the present invention and superior elongation at fracture of the cured product (the cured product is included in the anti-slip layer) obtained by curing the specific urethane composition. The latent curing agent having an oxazolidine ring can be hydrolyzed to produce a curing agent having a reactive amine (e.g., an imino group) and a hydroxyl group. 【0053】 The oxazolidine ring that the latent curing agent may have is not particularly limited. For example, one preferred embodiment is that the carbon atom at position 2 of the oxazolidine ring (the single carbon atom between the oxygen atom and the nitrogen atom) is substituted with an alkyl group. The alkyl group is not particularly limited. The alkyl group may be linear or branched, and one preferred embodiment is that it is branched. Examples of the linking groups having the above-mentioned urethane bond include groups represented as -ABCDE-, where A, C, and E are each independently alkylene groups having 1 to 10 carbon atoms, and B and D are each urethane bonds. The alkylene group having 1 to 10 carbon atoms may be linear or branched, with linear being one preferred embodiment. In the above embodiment, the alkylene group having 1 to 10 carbon atoms as A and E is preferably an alkylene group having 1 to 6 carbon atoms. In one preferred embodiment, the alkylene group having 1 to 10 carbon atoms as C is an alkylene group having 4 to 8 carbon atoms. The above linking group can be bonded to, for example, a nitrogen atom on the oxazolidine ring. 【0054】 Examples of bis-oxazolidine compounds in which two oxazolidine rings are crosslinked by a linking group having a urethane bond include the compound represented by the following formula. [ka] The method for preparing compounds having an oxazolidine ring as latent curing agents is not particularly limited. For example, conventionally known methods can be used. 【0055】 (Content of latent hardening agent) From the viewpoint of achieving superior effects of the present invention, the content of the latent curing agent is preferably 5.0 to 20% by mass of the total amount of the specific urethane composition. 【0056】 (Filler) The specific urethane-based composition may further contain a filler. Examples of fillers include calcium carbonate and silica. From the viewpoint of achieving superior effects of the present invention, the filler preferably contains calcium carbonate. If the specific urethane composition further contains a filler, the filler content is preferably 20 to 40% by mass of the total amount of the specific urethane composition, from the viewpoint of achieving superior effects of the present invention. Furthermore, the above-mentioned filler does not contain the aggregate mentioned above. 【0057】 (At least one selected from the group consisting of UV absorbers, light stabilizers, and antioxidants) From the viewpoint of achieving superior effects of the present invention, the specific urethane composition preferably further contains at least one selected from the group consisting of ultraviolet absorbers, light stabilizers, and antioxidants, and more preferably contains ultraviolet absorbers, light stabilizers, and antioxidants. 【0058】 (UV absorber) Examples of UV absorbers include benzotriazole-based UV absorbers such as 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, triazine-based UV absorbers such as 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol, benzophenone-based UV absorbers such as octabenzone, and benzoate-based UV absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate. 【0059】 (Light stabilizer) Examples of light stabilizers include hindered amine-based light stabilizers, specifically bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine. 【0060】 (Antioxidant) Examples of antioxidants include hindered phenol antioxidants, specifically pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diyrbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propioamide], benzenepropanoate 3,5-bis(1,1-dimethylethyl)-4-hydroxyC7-C9 side-chain alkyl ester, and 2,4-dimethyl-6-(1-methylpentadecyl)phenol. 【0061】 (Content of UV absorbers, etc.) If the specific urethane composition further contains the above-mentioned ultraviolet absorber, etc., the content of at least one selected from the group consisting of ultraviolet absorbers, light stabilizers, and antioxidants (or the total content of these if all of them are included) is preferably 0.1 to 3.0% by mass of the total amount of the specific urethane composition, from the viewpoint of achieving superior effects of the present invention. 【0062】 (Additives) The specific urethane-based composition may contain additives in addition to the above-mentioned components. Examples of additives include isocyanate oligomers (e.g., trimers of diisocyanate compounds), solvents, plasticizers, adhesion promoters, curing accelerators (e.g., acid catalysts), and storage stability improvers (dehydrating agents). When the specific urethane-based composition further contains various additives, their types and amounts can be selected as appropriate. 【0063】 (solvent) If the specific urethane composition further contains a solvent, the solvent should be a compound that does not react with the above-mentioned components contained in the specific urethane composition. Examples of solvents include conventionally known organic solvents such as aliphatic solvents like n-hexane, alicyclic solvents like cyclohexane, aromatic solvents like toluene and xylene, and petroleum-based solvents containing these. 【0064】 (Methods for manufacturing specific urethane-based compositions, etc.) A method for producing a specific urethane-based composition is, for example, by using the above-mentioned components in the above-mentioned amounts and mixing them together. The specific urethane-based composition can be used as the matrix for the anti-slip layer that constitutes the outermost layer of the waterproof membrane of the present invention. [Examples] 【0065】 The present invention will be described in more detail below based on examples. The materials, quantities, proportions, processing details, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples. 【0066】 [Preparation of Urethane Prepolymer 1] 5.68 parts by mass of 1,4-butanediol with a molecular weight of 90 (1,4-BD, OH value 1247 mgKOH / g, manufactured by Mitsubishi Chemical Corporation; the same applies hereafter) and 54.1 parts by mass of polypropylene glycol with a number average molecular weight of 2000 (product name: Sannix PP-2000NS, bifunctional, OH value 56±2 mgKOH / g, manufactured by Sanyo Chemical Industries, Ltd.; the same applies hereafter) were weighed and mixed in a molar equivalent ratio of 1,4-butanediol:the above polypropylene glycol = 70:30, and then IPDI40.21 with a molecular weight of 222 was added to the solution. Parts by mass (product name: IPDI, manufactured by Hyulls; the same applies hereinafter) were added to a liquid mixture such that the molar equivalent ratio (NCO / OH) of isocyanate groups in IPDI to the total number of hydroxyl groups in 1,4-butanediol and polypropylene glycol was 2.00. The liquid mixture was then heated while stirring, and a tin catalyst was added to the total liquid mixture in an amount of 0.01% by mass of the total liquid mixture. The mixture was reacted at 95°C for 2.5 hours to obtain urethane prepolymer 1. Urethane prepolymer 1 includes 1,4-BD with IPDI added, and the above-mentioned polypropylene glycol with IPDI added, and the isocyanate group content of urethane prepolymer 1 was 7.6% by mass of urethane prepolymer 1. 1,4-Butanediol: Urethane prepolymer 1, in which the molar equivalent ratio of the above polypropylene glycol is 70:30, falls under the category of a specific urethane prepolymer. 【0067】 [Preparation of Urethane Prepolymer 3] Urethane prepolymer 3 was obtained by preparing urethane prepolymer 3 in the same manner as described in [Preparation of Urethane Prepolymer 1] above, except that the molar equivalent ratio of 1,4-butanediol to polypropylene glycol was changed to 50:50. The amount of 1,4-butanediol used was 3.02 parts by mass, the amount of polypropylene glycol with a number average molecular weight of 2000 was 67.06 parts by mass, and the amount of IPDI used was 29.91 parts by mass. Urethane prepolymer 3 included 1,4-BD with IPDI added, and the above-mentioned polypropylene glycol (Sannix PP-2000NS) with IPDI added, and the isocyanate group content of urethane prepolymer 3 was 5.6% by mass. 1,4-Butanediol: Urethane prepolymer 3, in which the molar equivalent ratio of the above polypropylene glycol is 50:50, does not fall under the category of a specified urethane prepolymer. 【0068】 [Preparation of Urethane Prepolymer 4] Urethane prepolymer 4 was obtained by preparing urethane prepolymer 4 in the same manner as described in [Preparation of Urethane Prepolymer 1] above, except that the molar equivalent ratio of 1,4-butanediol to polypropylene glycol was changed to 80:20. The amount of 1,4-butanediol used was 7.84 parts by mass, the amount of polypropylene glycol with a number average molecular weight of 2000 used was 43.57 parts by mass, and the amount of IPDI used was 48.58 parts by mass. The urethane prepolymer 4 included 1,4-BD with IPDI added, and the above-mentioned polypropylene glycol (Sannix PP-2000NS) with IPDI added, and the isocyanate group content of the urethane prepolymer 4 was 9.2% by mass. 1,4-Butanediol: The urethane prepolymer 4 having a molar equivalent ratio of 80:20 with the above polypropylene glycol does not fall under the category of a specific urethane prepolymer used in the present invention. 【0069】 [Preparation of one-component urethane-based composition] Each component shown in Table 1 was used in the amounts (mass%) shown in the table, and these were mixed to prepare each one-component urethane-based composition. 【0070】 [Preparation of test specimens] • Test specimens for tensile testing, tear strength testing, and hardness testing. Each of the one-component urethane compositions obtained as described above was cured at 23°C for 24 hours, and then cured at 60°C for 24 hours to obtain cured products. Using the above cured products, test specimens for tensile testing and tear strength testing were prepared in accordance with JIS A 6021:2011. Test specimens for hardness testing were prepared in accordance with DIN 53505-D:2000 standard. • Test specimens for weather resistance evaluation Each of the one-component urethane compositions obtained as described above was cured for 7 days under conditions of 23°C and 50% relative humidity to obtain initial cured products. As described above, each of the initial cured materials obtained was irradiated with ultraviolet light from a xenon arc lamp for 2150 hours using a xenon weather meter (ATLAS Ci4000), and post-irradiation test specimens were obtained. 【0071】 [evaluation] • Tensile test, tear strength test, hardness Tensile and tear strength tests were performed on the above test specimens under conditions of 23°C in accordance with JIS A 6021:2011. The hardness (D) of the above test specimens was measured according to the DIN 53505-D:2000 standard. If the elongation rate at break of the above test specimen is 200% or more, the resulting waterproof film is less prone to cracking, which is preferable. The results are shown in Table 1. 【0072】 (Abrasion resistance) In this invention, when the hardness of the test specimen was between 40 and 65, the abrasion resistance of the waterproof membrane (anti-slip layer) was evaluated as excellent. On the other hand, if the hardness of the test specimen was less than 40 or greater than 65, the abrasion resistance of the waterproof membrane (anti-slip layer) was evaluated as insufficient. 【0073】 ·Color difference (ΔE * ab ) The color difference (ΔE) between the initial cured material and the post-irradiation test specimen used for weather resistance evaluation. * ab ) is based on JIS Z 8781-4:2013 Colorimetric Measurement - Part IV: CIE 1976 L * a* b * It was determined according to the color difference of 4.3 in the color space. The above results are shown in Table 1. 【0074】 The color of the initial cured product is L *1 , a *1 , b *1 and is represented by, and the color of the test piece after irradiation is L *2 , a *2 , b *2 If it is represented by, the color difference (ΔE * ab ) between the initial cured product and the test piece after irradiation is obtained by the following formula. ΔE * ab =[(ΔL * )<{ 2 +(Δa * ) 2 +(Δb * ) 2 1 / 2 ΔL * =L *1 -L *2 Δa * =a *1 -a *2 Δb * =b *1 -b *2 【0075】 (Weather resistance) In the present invention, when the above color difference (ΔE * ab ) was 1.00 or less, it was evaluated that the color change was small and the weather resistance was excellent. The smaller the above color difference (ΔE * ab ), the better the weather resistance. On the other hand, when the above color difference (ΔE * ab ) exceeded 1.00, it was evaluated that the weather resistance was insufficient. In addition, when the weather resistance was not evaluated, it was indicated as "not measured". 【0076】 【Table 1】 ​ 【0077】 The details of each component shown in Table 1 above are as follows: • Urethane prepolymers 1, 3-4: Urethane prepolymers 1, 3-4 prepared as described above. • Filler: Calcium carbonate. Product name: Whiteon P-30, manufactured by Toyo Fine Chemical Co., Ltd. • Latent curing agent: A urethane-crosslinked bis-oxazolidine compound (structure shown below). Hydrolysis yields a reactive amine and a crosslinking agent having a hydroxyl group. [ka] The method for preparing the above-mentioned urethane-crosslinked bis-oxazolidine compound is as follows. 435.0 g of diethanolamine was placed in a reaction vessel equipped with a stirrer, thermometer, nitrogen-sealed tube, and heating / cooling device, followed by the addition of 183.3 g of toluene. While stirring, 328.3 g of isobutyraldehyde was added, and the dehydration reaction was continued at 110-150°C for 3 hours, after which 74.5 g of water was removed using an ester tube. The mixture was then reduced in pressure to remove excess isobutyraldehyde and toluene, yielding a hydroxyl-containing oxazolidine compound. 341.0 g of hexamethylene diisocyanate was added to 658.9 g of this hydroxyl-containing oxazolidine compound, and the mixture was heated at 80°C for 8 hours. The urethane reaction was terminated when the measured isocyanate group content, determined by titration, fell to 0.0% by mass or less. The resulting reaction product was a translucent liquid at room temperature. The resulting reaction product is a urethane-crosslinked bis-oxazolidine compound having the structure described above. • Eversorb S02: A blend of UV absorbers, hindered amine light stabilizers (HALS), and antioxidants. Manufactured by Everlight Chemical. Desmodur 4470: A trimer of isophorone diisocyanate. Manufactured by Sumitomo Chemical Covestro. Isocyanate group content: 11.9% by mass. • Solvent: C9 and C10 alkylcyclohexane isomer compound (Swaclean 150), manufactured by Maruzen Petrochemical Co., Ltd. • Acid catalyst: Octylic acid. 【0078】 The results in Table 1 show that the cured products of the urethane compositions in Examples 1 to 5 exhibited excellent abrasion resistance and weather resistance. Therefore, the waterproof layer of the present invention, in which the outermost anti-slip layer is formed from a specific urethane composition containing a specific urethane prepolymer, can be said to have excellent abrasion resistance and weather resistance. On the other hand, the cured product of the urethane composition of Comparative Example 1, which contained urethane prepolymer 3 in which the butanediol:polyoxyalkylene polyol was outside the specified range, had low hardness and insufficient abrasion resistance. Furthermore, its physical properties, such as tensile strength, were insufficient compared to the examples. The cured product of the urethane composition of Comparative Example 2, which contained a urethane prepolymer 4 in which the butanediol:polyoxyalkylene polyol was outside the specified range, had excessively high hardness and insufficient abrasion resistance. Furthermore, the cured product of Comparative Example 2 cracked without elongating in a tensile test, indicating insufficient physical properties in terms of elongation at fracture. Based on the results above, weather resistance tests were not conducted for Comparative Examples 1 and 2. [Explanation of symbols] 【0079】 1 Parking 11 Parking area 13, 23 line 15, 21 Driving range 17 Arrows 25 slopes 27 Paul 30 waterproof membrane 31 Floor (parking lot floor) 35 Primer layer 37 Waterproof layer 39. Anti-slip layer (outermost layer of waterproof membrane 30)

Claims

[Claim 1] A waterproof membrane that is placed on and exposed on the floor of a parking area for parking vehicles, wherein the waterproof membrane is laminated on the floor in the order of a primer layer, a waterproof layer, and an anti-slip layer, the anti-slip layer being the outermost layer of the waterproof membrane, the anti-slip layer being composed of a urethane composition and aggregate, the urethane composition being a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, the urethane prepolymer being formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of the butanediol to the polyoxyalkylene polyol (butanediol:polyoxyalkylene polyol) being 60:40 to 75:

25. [Claim 2] The waterproof film according to claim 1, wherein the isocyanate group content of the urethane prepolymer is 6.0 to 9.0% by mass of the urethane prepolymer. [Claim 3] The waterproof membrane according to claim 1, wherein the parking area further has a driving area for vehicles to drive on, and the parking area and the driving area together form the floor. [Claim 4] A production method for producing a waterproof membrane to be placed on and exposed on the floor of a parking lot having a parking area for parking vehicles, the method comprising the step of laminating a primer layer, a waterproof layer, and an anti-slip layer on the floor in this order, wherein the anti-slip layer is the outermost layer of the waterproof membrane, the anti-slip layer is composed of a urethane composition and aggregate, the urethane composition is a one-component urethane composition containing a urethane prepolymer having isocyanate groups and a latent curing agent, the urethane prepolymer is formed from a polyisocyanate compound having multiple isocyanate groups per molecule and a polyol containing butanediol and polyoxyalkylene polyol, and the molar equivalent ratio of the butanediol to the polyoxyalkylene polyol (butanediol:polyoxyalkylene polyol) is 60:40 to 75:25.

Images