Flood prevention sheet

Abstract

This invention provides a flood-proof sheet that offers excellent water-prevention performance through building openings, can be easily removed after use, can be stored compactly, and can be easily reused when flooding is anticipated. [Solution] A water-preventing sheet for preventing water from seeping into the interior of a building, comprising a base layer in which a fiber cloth is embedded in a vulcanized elastomer, and an adhesive layer on one side of the base layer made of a cured silicone adhesive composition, characterized in that the adhesive strength of the adhesive layer is 2 to 10 N / 25 mm.

Description

[Technical Field]

[0001] This invention relates to a flood-prevention sheet for preventing water from entering the interior of a building. [Background technology]

[0002] In Japan, flooding caused by typhoons and torrential rains has been a frequent occurrence for a long time. In particular, in recent years, localized torrential rains caused by linear rainbands have led to river overflows and road flooding, and there has been an increasing trend of serious flooding damage to buildings such as houses, shops, factories, and warehouses.

[0003] Sandbags are a common measure to prevent flooding, but they are heavy, difficult to transport, and require storage space. In particular, using sandbags is not practical for typical houses, and they are not sufficient to protect against water seeping in through gaps in the building.

[0004] Patent Document 1 discloses a water-prevention sheet made of a resin sheet with a waterproofing function and an adhesive layer applied to prevent water from seeping in through openings in buildings such as entrance doors. However, while resin sheets have excellent weather resistance and rigidity, they have difficulty conforming to uneven surfaces such as doors with complex designs, and there is a risk of water seeping in through even small gaps. Patent Document 2 discloses a waterproof sheet made by coating and laminating a fiber-reinforced rubber sheet with silicone adhesive. Compared to conventional waterproof sheets, it has features such as being less prone to damage and being able to follow cracks and shifts in the applied surface. However, it is intended for use in situations where it is firmly attached for a long period of time and is not intended for use in preventing flooding of buildings. It is not intended to be used by attaching it to openings in houses etc. when flooding occurs, and then peeling it off without damage and storing it, and only using it when flooding is expected. In either case, the strong adhesive force may damage the paint or resin coating of the building when removed, and it is difficult to reuse the removed waterproof sheet.

[0005] Due to these circumstances, there has been a demand for a waterproof sheet that can follow even complex shapes, has excellent water resistance, can be easily peeled off without damaging the coating film of the adherent after use, can be compactly stored, and can be easily reused.

Prior Art Documents

Patent Documents

[0009] The flood-prevention sheet of the present invention offers excellent performance in preventing flooding from openings in buildings such as houses, can be easily peeled off after use, can be stored compactly, and is also easy to reuse. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing one embodiment of the flood prevention sheet according to the present invention. [Figure 2] This is a perspective view showing an example in which the water-repellent sheet according to the present invention is installed from the indoor side in the gap between the bottom of the door and the door frame. [Figure 3] This is a perspective view showing an example in which the water ingress prevention sheet according to the present invention is installed from the outside in the gap between the bottom of the door and the door frame. [Figure 4-1] This is a perspective view showing the door in the open position with the adhesive layer of the water-prevention sheet according to the present invention attached to the bottom of the door. [Figure 4-2] This is a perspective view showing the state in which the water-prevention sheet according to the present invention is sandwiched in the gap between the door and the door frame after the adhesive layer of the sheet has been attached to the bottom of the door and the door has been closed. [Figure 5] This is a photograph showing the exterior of a flood prevention performance testing device. [Figure 6] This is a front view showing the flood prevention sheet attached from the inside to the gap between the bottom of the door and the door frame of the flood prevention performance testing device. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0012] The water-repellent sheet of the present invention has an adhesive layer on one side of a base layer which is an elastomer reinforced with fiber cloth, and is used to prevent water from seeping into the interior of a building from the outside. Specifically, it can be used by applying the adhesive layer to the gaps that occur between the opening / closing mechanism and the frame or floor of the opening, or to openings such as ventilation holes under the floor, while the opening / closing mechanism of a building, such as a door or shutter, is closed.

[0013] The water-repellent sheet of the present invention can conform to complex shapes because its base layer is made of elastomer. Furthermore, through optimization of the adhesive layer, it can adhere firmly to surfaces such as doors, while being removable without damaging the surface's coating. After removal, it can be compactly stored by rolling it up with the adhesive layer facing inward and reused as is. If the adhesive strength decreases due to dust or sand adhering to the adhesive layer, it can be restored and reused by washing it with water or a neutral detergent and then thoroughly wiping off the water.

[0014] [Base material layer] The base layer constituting the water-preventing sheet of the present invention is characterized by being an elastomer, taking into consideration the sheet's manufacturing process, conformability to the adherend, and ease of handling. The type of elastomer is not particularly limited as long as it is vulcanizable, and thermosetting elastomers such as synthetic rubbers like diene rubbers and non-diene rubbers, or natural rubbers can be used. Examples of diene rubbers include isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), and hydrogenated nitrile rubber (HNBR). Examples of non-diene rubbers include butyl rubber (IIR), ethylene propylene rubber (EPDM), fluororubber (FKM), thermosetting urethane rubber, and silicone rubber. Considering heat resistance, weather resistance, and cold resistance, it is preferable that the elastomer be one or more selected from the group consisting of silicone rubber, EPDM rubber, butyl rubber, chloroprene rubber, and natural rubber. Among these, silicone rubber is preferred because it can be used in environments ranging from cold to extremely hot, it deteriorates relatively little over time and can be reused even after long-term storage, and it can be rolled up and stored with the adhesive layer facing inward.

[0015] The silicone rubber used to provide the above-mentioned base layer may be any of the following silicone rubber compositions: organic peroxide curing type, addition reaction curing type, ultraviolet curing type, or electron beam curing type. The base layer is formed from vulcanized silicone rubber, that is, a cured product of the above-mentioned silicone rubber composition. In this case, any curing type is acceptable, but it is preferable to form the base layer with a cured product obtained from an addition (hydrosilylation) reaction curing type silicone rubber composition or an organic peroxide curing type silicone rubber composition, as this allows for molding in a short time by heating.

[0016] As an organic peroxide-curable silicone rubber composition, an organopolysiloxane having two or more alkenyl groups in one molecule is used, to which an effective amount of organic peroxide as a curing agent is added (usually 1 to 10 parts by mass per 100 parts by mass of the above organopolysiloxane). Examples of organic peroxides include acyl organic peroxides represented by para-methylbenzoyl peroxide and ortho-methylbenzoyl peroxide, alkyl organic peroxides represented by dicumyl peroxide and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, parkerized organic peroxides, and peroxyketal organic peroxides.

[0017] In the case of addition reaction curing, an organosiloxane polymer having two or more alkenyl groups per molecule is reacted with a compound having at least two functional groups that react with alkenyl groups per molecule, in the presence of a catalyst. Hydrosilylation reactions are a good example of this type. This addition reaction curing type silicone rubber composition uses an alkenyl-containing organopolysiloxane having two or more alkenyl groups, such as vinyl groups, per molecule; an organohydrogenpolysiloxane having two or more, preferably three or more, hydrosilyl groups per molecule (usually in an amount where the molar ratio of hydrosilyl groups to alkenyl groups is 0.5 to 4); and a platinum group metal-based addition reaction catalyst, such as platinum or a platinum compound (usually in an amount of about 1 to 1,000 ppm (calculated in terms of metal mass) as platinum group metal relative to the alkenyl-containing organopolysiloxane).

[0018] In the case of UV-curing type rubber compounds, the rubber compound containing a photopolymerization initiator is irradiated with ultraviolet light at a wavelength of 200-400 nm, and cured in a few seconds to tens of seconds. Typical wavelengths used for irradiation are 254 nm or 365 nm. Any known photopolymerization initiator can be used, with Irgacure 184 (manufactured by BASF) being an example.

[0019] In electron beam curing, electrons are artificially accelerated, and the energy of the electron beam is used as a beam to cure the material. Vulcanization is adjusted by the acceleration voltage and penetration depth. There are no particular limitations on the electron beam vulcanization equipment; commercially available equipment can be used.

[0020] Furthermore, commercially available silicone rubber compositions may be used as described above. For example, KE-971-U and KE-675-U manufactured by Shin-Etsu Chemical Co., Ltd. can be used as organic peroxide curing type silicone rubber compositions, and KE-551-U, KE-1300T, and KE-1950-60-A / B manufactured by Shin-Etsu Chemical Co., Ltd. can be used as addition reaction curing type silicone rubber compositions.

[0021] Since the strength of the above-mentioned base material layer depends on the physical properties of the fiber cloth, the rubber properties of the silicone rubber are not particularly limited and should be any material that exhibits rubber properties in a cured state. In particular, it is preferable that it does not feel extremely sticky to the touch. The rubber properties should preferably be such that, according to the measurement method in accordance with JIS K6249:2003, the durometer type A hardness is 10 to 90, the tensile strength is 2 MPa or more, especially 2 to 15 MPa, the elongation at break is 50 to 800%, and the tear strength is 2 kN / m or more, especially 2 to 40 kN / m. Within these ranges of physical properties is preferable because it makes it less likely for scratches or damage to occur on the surface of the water-prevention sheet.

[0022] The fibrous fabric of the base layer described above reinforces the elastomer. The fibrous fabric is a cloth woven from one or more fibers selected from the group consisting of glass fibers, carbon fibers, aramid fibers, and silicon carbide fibers. The specifications of the fibers are not particularly limited, but the yarn count of the constituent threads should be 5-600 tex for both warp and weft, the weave density should be 10-150 threads / 25 mm, the thickness should be 0.02-0.6 mm, and the tensile strength should be 70 N / 25 mm or more. Plain weave and satin weave are preferred. In particular, it is preferable that the fabric has an appearance in which the bottom surface is visible when a single flat fiber is placed. The degree of transparency should preferably be 50-99% total light transmittance, measured in accordance with the provisions of JIS K7361:1997, and more preferably 60-99%. Transparency of 50% or more is sufficient. Furthermore, transparency is preferable from the viewpoint of the design of the water-prevention sheet.

[0023] The base material layer reinforced with the above-mentioned fiber cloth has a tensile strength of 15 MPa or more, usually 100 MPa or less, preferably 20 to 100 MPa, and more preferably 50 to 100 MPa. The tear strength is, for example, 50 kN / m or more, preferably 100 kN / m or more, more preferably 300 kN / m or more, and even more preferably 400 kN / m or more, and there is no particular upper limit, but for example it is 700 kN / m or less. It is preferable that the tear strength is within the above range because damage to the water-prevention sheet is less likely to occur both during the first use and during reuse.

[0024] The above-mentioned base layer is made by embedding a fibrous cloth in a vulcanized elastomer. The base layer can be manufactured, for example, by applying an unvulcanized silicone rubber composition to both sides of the fibrous cloth and then curing it. In particular, using a liquid silicone rubber composition is preferable because the composition penetrates the mesh of the fibers from both sides of the fibrous cloth, and the fibrous cloth and the composition can be cured together as one unit. As a result, a base layer is obtained in which the fibrous cloth is embedded in the silicone rubber, making it difficult for the fibrous cloth and silicone rubber to separate. As will be described later, if the thickness of the fiber cloth is 3 to 80% of the thickness of the base layer, the fiber cloth will be suitably embedded in the vulcanized elastomer, which is preferable.

[0025] [Adhesive layer] The water-resistant sheet of the present invention has an adhesive layer made of a cured silicone adhesive composition on one side of the base layer. For example, as shown in Figure 1, a water-resistant sheet 5 is provided in which the silicone rubber composition is applied to both sides of a fiber cloth 1, and an adhesive layer 4 is laminated on one side of the base layer 3 formed by curing, and curing. In Figure 1, the fiber cloth 1 is embedded in the cured silicone rubber composition 2 (vulcanized elastomer), and the adhesive layer 4 is laminated on the cured silicone rubber composition 2 on one side of the base layer 3. Note that the configuration of the base is not limited to the example in Figure 1.

[0026] Here, the adhesive layer may use a conventionally known silicone adhesive composition, but the combination and molding conditions differ from those previously proposed, and it is preferable to have the following characteristics. That is, the silicone adhesive composition consists of the following components (A) to (D), (A) A linear organopolysiloxane having alkenyl groups with 2 to 8 carbon atoms at both ends of the molecular chain, comprising (A-1) and (A-2) below, 100 parts by mass, (A-1) Alkenyl group-containing organopolysiloxane with a viscosity of 30 to 1,000 Pa·s at 25°C, 95.0 to 99.9% by mass. (A-2) Kinematic viscosity at 25°C is 30-10,000 mm² 2 Alkenyl group-containing organopolysiloxane, 0.1-5.0% by mass, (B)R3SiO 1 / 2 Unit, R 1 R2SiO 1 / 2 Units, and SiO 4 / 2 unit (In the above formula, R is independently an alkyl group having 1 to 6 carbon atoms, R 1 A resinous organopolysiloxane consisting of an alkenyl group having 2 to 8 carbon atoms, 5 to 100 parts by mass, (C)R3SiO 1 / 2 Unit: R2HSiO 1 / 2 Units, and SiO 4 / 2 unit A resinous organohydrogenpolysiloxane comprising (wherein R is the same as above), an amount such that the amount of hydrosilyl groups in component (C) is in the range of 0.2 to 1.0 moles relative to the total amount of alkenyl groups in component (A) and component (B), (D) Addition reaction catalyst, amount of catalyst An addition-curing silicone adhesive composition containing is preferred, and the adhesive layer is preferably formed from its cured product.

[0027] Component (A) of the above addition-curing silicone adhesive composition is a linear organopolysiloxane having alkenyl groups with 2 to 8 carbon atoms at both ends of the molecular chain.

[0028] Examples of alkenyl groups having 2 to 8 carbon atoms include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups. Among these, vinyl and allyl groups are preferred. The content of alkenyl groups in the organopolysiloxane is preferably 0.001 to 5 mol / 100g, more preferably 0.001 to 1 mol / 100g. These alkenyl groups must be bonded to the silicon atoms at both ends of the molecular chain, but they may also be bonded to silicon atoms in the middle of the molecular chain. If the content of alkenyl groups is 0.001 mol / 100g or more, sufficient rubber properties can be obtained in the adhesive layer, and if it is 5 mol / 100g or less, sufficient adhesive strength can be obtained without the hardness becoming too high.

[0029] Other substituents besides alkenyl groups include monovalent hydrocarbon groups having 1 to 10 carbon atoms. Examples of monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups, aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups, and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups. In particular, it is preferable that 90 mol% or more of all substituents excluding alkenyl groups are methyl groups.

[0030] The above component (A) consists of the following combinations of (A-1) and (A-2), which have different degrees of polymerization. (A-1) Alkenyl group-containing organopolysiloxane with a viscosity of 30 to 1,000 Pa·s at 25°C (A-2) Kinematic viscosity at 25°C is 30-10,000 mm² 2 / s Alkenyl group-containing organopolysiloxane

[0031] The viscosity of component (A-1) is preferably 30 to 1,000 Pa·s, more preferably 50 to 500 Pa·s, and even more preferably 80 to 200 Pa·s. The kinematic viscosity of component (A-2) is 30 to 10,000 mmHg. 2 / s is preferred, and 100~7,000mm 2 / s is more preferable, 500~6,000mm 2 / s is more preferable. In this invention, the viscosity of component (A-1) is the absolute viscosity measured at 25°C using a rotational viscometer as described in JIS K6249:2003, and the kinematic viscosity of component (A-2) refers to the value measured at 25°C using a Cannon-Fenske viscometer as described in JIS Z8803:2011.

[0032] The composition ratio of component (A-2) in component (A) (the mass fraction of component (A-2) relative to the total mass of components (A-1) and (A-2)) is 0.1 to 5.0% by mass, preferably 1.0 to 4.0% by mass. Component (A-2) contributes to the shape retention of the adhesive, but if it is between 0.1% by mass and 5.0% by mass, the adhesive is flexible and has sufficient adhesive strength. The composition ratio of component (A-1) in component (A) (the mass fraction of component (A-1) relative to the total mass of components (A-1) and (A-2)) is 95.0 to 99.9% by mass, preferably 96.0 to 99.0% by mass. Furthermore, components (A-1) and (A-2) may be used individually or in combination of two or more.

[0033] (B) The resinous organopolysiloxane component is R3SiO1 / 2 Unit, R 1 R2SiO 1 / 2 Units, and SiO 4 / 2 It consists of units. Here, R 1 R is an alkenyl group having 2 to 8 carbon atoms, and R is independently an alkyl group having 1 to 6 carbon atoms. Examples of R include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, and cyclohexyl groups.

[0034] (B) The resinous organopolysiloxane component is R3SiO 1 / 2 Units and R 1 R2SiO 1 / 2 Sum of units and SiO 4 / 2 Molar ratio with respect to units [(R3SiO 1 / 2 +R 1 R2SiO 1 / 2 ) / SiO 4 / 2 The molar ratio of 0.5 to 1.5 is preferably 0.6 to 1.3. A molar ratio of 0.5 to 1.5 provides sufficient rubber hardness and strength. Furthermore, the resinous organopolysiloxane of component (B) preferably has two or more alkenyl groups per molecule, and the alkenyl group content is 0.01 mol / 100 g or more, preferably in the range of 0.01 to 0.1 mol / 100 g. If the alkenyl group content is 0.01 mol / 100 g or more, sufficient rubber properties are obtained, and if it is 0.1 mol / 100 g or less, the adhesive will have an appropriate hardness and sufficient adhesive strength. The above-mentioned resinous organopolysiloxane may be a liquid with fluidity at 25°C, particularly with a pressure of 10 mPa·s or higher, preferably 50 mPa·s or higher, or it may be a solid with no fluidity. In the case of a solid, it may be dissolved in an organic solvent such as toluene. This resinous organohydrogenpolysiloxane can usually be produced by hydrolyzing a suitable chlorosilane or alkoxysilane by a method well known in the art.

[0035] The amounts of components (A) and (B) described above are preferably 5 to 100 parts by mass, more preferably 10 to 90 parts by mass, and particularly preferably 20 to 80 parts by mass, of component (B) per 100 parts by mass of component (A). If the amount of component (B) is above the lower limit, sufficient adhesive strength and durability will be achieved. If the amount of component (B) is below the upper limit, the adhesive will not become too hard and will have sufficient rubber properties. From the viewpoint of rubber properties, strength, and adhesiveness of the adhesive layer, it is preferable to use component (B) in combination with component (A).

[0036] Component (C) is a resinous organohydrogenpolysiloxane containing a hydrosilyl group, R3SiO 1 / 2 Unit: R2HSiO 1 / 2 Units, and SiO 4 / 2 It consists of units. Any organohydrogenpolysiloxane having at least two, preferably three or more, hydrosilyl groups in one molecule is acceptable, and the hydrosilyl groups in the molecule crosslink with alkenyl groups bonded to silicon atoms in components (A) and (B) through a hydrosilylation addition reaction, and act as a curing agent for curing the composition. Here, R is an alkyl group having 1 to 6 carbon atoms, independent of R in component (B).

[0037] (C) The resinous organohydrogen polysiloxane component is R3SiO 1 / 2 Units and R2HSiO 1 / 2 Sum of units and SiO 4 / 2 Molar ratio with respect to units [(R3SiO 1 / 2 +R2HSiO 1 / 2 ) / SiO 4 / 2 The mol / g ratio is preferably 0.5 to 1.5, and particularly preferably 0.6 to 1.3. The hydrosilyl group content can be, for example, 0.0005 to 0.02 mol / g, preferably 0.001 to 0.015 mol / g, so as to fall within the above range. The amount of resinous organohydrogenpolysiloxane in component (C) is preferably such that the amount of hydrosilyl groups in component (C) is in the range of 0.2 to 1.0 moles, particularly 0.3 to 0.8 moles, relative to the total amount of alkenyl groups in components (A) and (B). If the amount is above the lower limit, the hardness of the adhesive layer is appropriate, and it is easy to maintain the shape when peeled off. If the amount is below the upper limit, the hardness of the adhesive layer does not become too high, and sufficient adhesive strength is exhibited.

[0038] Here, the molar ratio of hydrosilyl groups of component (C) to the amount of alkenyl groups present in the system is expressed as H / Vi, and the theoretical crosslinking amount is the amount of crosslinking that would occur if 100% of the hydrosilyl groups in component (C) added to the system reacted with the alkenyl groups present in the system. That is, when H / Vi is 1 or less, the amount of hydrosilyl groups is the theoretical crosslinking amount, and when H / Vi is 1 or greater, the amount of alkenyl groups is the theoretical crosslinking amount. These functional group amounts may be amounts based on calculation formulas used in composition design, but it is more preferable to use measured values. The amount of functional groups can be measured by known analytical methods such as hydrogen gas generation amount or unsaturated group measurement, or NMR analysis. The amount of functional groups in the system is expressed as X × Y mol / g, where X mol / g is the amount of functional groups in the molecule and Y parts by mass is the amount added.

[0039] The addition reaction catalyst for component (D) can be any conventionally known catalyst, such as platinum black, platinum-dicin chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, complexes of chloroplatinic acid and vinylsiloxanes, platinum-based catalysts such as platinum bisacetate, palladium-based catalysts, and rhodium-based catalysts. The amount of this addition reaction catalyst can be a catalytic amount, and is usually around 0.5 to 1,000 ppm, particularly 1 to 500 ppm, by mass relative to the total amount of components (A) and (B) as platinum group metals.

[0040] [Adhesive layer hardness] The hardness of the adhesive layer is lower than that of the base material layer, and it is preferable that the hardness measured with a CSR2 type Asker rubber hardness tester (manufactured by Polymer Instruments Co., Ltd.) is between 3 and 30. More preferably, it is in the range of 5 to 25, and even more preferably 8 to 20. This hardness is such that when you touch the adhesive surface with your finger and slowly lift your finger away, the adhesive surface follows your finger. The greater the adhesive force, the more advantageous it is to lower the hardness of the adhesive layer. However, if the hardness is 3 or higher on the CSR2 type hardness tester, the shape will be maintained when the waterproof sheet is peeled off the surface after application, making it easy to reuse, and the adhesive force will be appropriate so as not to damage the paint on the surface. Furthermore, when the sheet is peeled off the surface, rolled up with the adhesive layer facing inward so that the adhesive layer surface is in direct contact with the base material layer surface, and then reused, the adhesive layer will stick to the base material layer, making it easy to unroll. This also makes it easier to clean and restore the adhesive layer if dust or sand adheres to it and reduces its adhesive strength. Furthermore, if the hardness is 30 or less, sufficient adhesive strength is achieved, resulting in good adhesion to the surface to be bonded and adequate water-repellent performance. Controlling the hardness is practically achieved by managing the molding and curing conditions, as described later.

[0041] [Adhesive strength] The adhesiveness of the present invention is indicated by the adhesive strength to the roughened surface of a polyethylene terephthalate resin film (product name: Matt Lumirror 125, manufactured by Kimoto Co., Ltd.) with one side roughened. A water-repellent sheet produced by the molding method described later is cut to a width of 25 mm, and the adhesive layer side of the sheet is attached and pressed with a roller five times back and forth with a load of 2 kg. Within 5 minutes, a 180° peel test is performed at a peeling speed of 300 mm / min. The present invention is characterized in that the adhesive strength at this time is 2 to 10 N / 25 mm, preferably 3 to 8 N / 25 mm, and more preferably 4 to 7 N / 25 mm. If it is less than 2 N / 25 mm, the adhesive strength is weak, and adhesion to the surface to be adhered to is weak, and sufficient water-repellent performance may not be obtained. If it is greater than 10 N / 25 mm, the adhesive strength is too strong and may damage the paint on the surface to be adhered to. Furthermore, when the adhesive layer is peeled off the surface to be attached, rolled up with the adhesive layer facing inward so that the adhesive layer surface is in direct contact with the substrate layer surface, and then stored compactly, there is a possibility that the adhesive layer may stick to the substrate layer when reused, making it difficult to unroll. Cleaning and restoration of the adhesive layer will also be difficult if dust or sand adheres to it and reduces its adhesive strength. The evaluation of adhesiveness can be done as described in the examples.

[0042] [Other additives to the base layer and adhesive layer] In addition to the components described above, the composition forming the base rubber layer and adhesive layer may optionally contain other components such as fillers like fumed silica, precipitated silica, quartz powder, diatomaceous earth, and calcium carbonate; conductive agents like carbon black, conductive zinc oxide, and metal powders; and heat-resistant agents like iron oxide and cerium oxide. Furthermore, it is optional to include hydrosilylation reaction control agents such as nitrogen-containing compounds, acetylene compounds, phosphorus compounds, nitrile compounds, carboxylates, tin compounds, mercury compounds, and sulfur compounds; colorants such as pigments and dyes; internal release agents such as dimethyl silicone oil; adhesion modifiers; and thixotropic agents.

[0043] [Adhesion treatment of the substrate layer surface] An adhesive layer is laminated on the base layer of the water-preventing sheet of the present invention. In order to strengthen the interlayer adhesion between the base layer and the adhesive layer, the surface of the base layer that is in contact with the adhesive layer may be subjected to a dry surface modification treatment selected from the group consisting of plasma treatment, corona treatment, ultraviolet irradiation treatment, or primer treatment.

[0044] Plasma treatment methods include treating the surface of the substrate layer to which the adhesive layer will be laminated with atmospheric pressure plasma or vacuum plasma before lamination. Corona treatment methods include treating the surface of the substrate layer by irradiating it with high-frequency, high-voltage corona discharge. Ultraviolet irradiation treatment methods are not limited to any treatment that irradiates with ultraviolet light. Specifically, it may be general ultraviolet treatment (UV treatment) that irradiates with ultraviolet light in a wide wavelength range or multiple wavelengths, or it may be excimer ultraviolet treatment that irradiates with excimer ultraviolet light of a single wavelength. The above dry surface modification can be carried out using commercially available equipment. Through these treatments, the surface of the silicone rubber can be chemically modified, that is, adhesion can be improved by introducing polar groups (such as highly hydrophilic silanol groups) to increase the surface energy or by promoting the generation of fine irregularities. Since these polar groups are unstable and their effect diminishes over time, it is preferable to perform the treatment immediately before laminating the adhesive layer.

[0045] One method of priming involves applying a silane coupling agent diluted with an organic solvent such as toluene to the surface of the substrate layer to which the adhesive layer will be laminated, before the adhesive layer is laminated. After air drying, the organic solvent is completely evaporated at a temperature of about 80°C. This treatment forms a silane coupling agent layer on the surface of the substrate layer, which strengthens the adhesion with the adhesive layer.

[0046] [Release treatment for the surface of the substrate layer] The water-repellent sheet of the present invention can be used by attaching it to a surface such as a door, then peeling it off the surface, and rolling it up with the adhesive layer facing inward so that the adhesive layer surface is in direct contact with the base material layer surface for compact storage. Long-term storage in this state is also anticipated, and the adhesive layer may stick to the base material layer, making it difficult to unroll. To prevent this adhesion of the adhesive layer to the base material layer, a release treatment may be applied to the surface of the base material layer opposite to the side with the adhesive layer.

[0047] One method of mold release treatment involves applying a silicone release agent containing a fluoroalkyl group, diluted with an organic solvent such as toluene, to the surface of the substrate layer. After air drying, the mixture is heated to completely evaporate and harden the organic solvent, forming a release layer on the substrate layer surface. To ensure strong adhesion with the silicone release agent, it is advisable to pre-treat the substrate layer with a dry surface modification treatment such as plasma treatment, corona treatment, or ultraviolet irradiation. The specific treatment should be carried out as described above.

[0048] [Thickness composition] The thickness of the above-mentioned water-prevention sheet is preferably 0.5 to 6 mm, more preferably 0.8 to 3.5 mm. Of this, the thickness of the base material layer is preferably 0.2 to 3 mm, more preferably 0.3 to 1.5 mm. If it is less than 0.2 mm, it may be insufficient to make the most of the elasticity of the sheet, and if it exceeds 3 mm, the weight will be large, which may affect adhesion and may be costly. In this case, it is preferable that the thickness of the fiber cloth be in the range of 3 to 80% of the thickness of the base material layer, and more preferably 5 to 70%. If it is 3% or more, the reinforcing effect of the fiber cloth will be sufficient and handling will be improved. If it is 80% or less, the rubber elasticity of the base material layer will not be suppressed and the ability to follow the irregularities of the adherend will be improved. Furthermore, the thickness of the adhesive layer is preferably in the range of 0.3 to 3 mm, more preferably in the range of 0.5 to 2 mm. If it is 0.3 mm or more, the irregularities of the surface of the adherend to which the adhesive layer is attached can be sufficiently absorbed, and if it is 3 mm or less, the rubber strength of the adherend surface will not be affected by the adhesive layer and there will be no risk of rubber failure.

[0049] [Protective film] In the water-resistant sheet of the present invention, a resin film may be applied to the surface of the adhesive layer (a resin film is attached to the surface of the adhesive layer) in order to protect the surface of the adhesive layer. This resin film must have release properties relative to the adhesive layer material, and examples include a polyethylene terephthalate film treated on one side with an acrylic release agent, or a polyethylene film with a silk-like embossed finish. When attaching the water-resistant sheet of the present invention to an object such as a door, this resin film should be peeled off before use.

[0050] [How to manufacture a flood-proof sheet] This section describes a method for forming a water-resistant sheet. An elastomer is applied to a fibrous fabric by dipping, coating, calendering, screen printing, etc., and then cured to obtain a base layer in which the fibrous fabric is embedded in the vulcanized elastomer. In this case, coating molding is preferable because it can be used effectively. An adhesive layer is laminated onto the above-mentioned base material layer. After forming the base material layer in which the fiber cloth is embedded in the vulcanized elastomer, a composition for forming the adhesive layer on the base material layer can be applied by dipping, coating, screen printing, etc., and coating molding is preferred as it can be suitably used. The curing conditions are preferably in the range of 10 seconds to 1 hour at 80 to 250°C. Furthermore, after-curing may be performed for about 1 to 100 hours at 120 to 250°C for purposes such as removing low molecular weight components.

[0051] [Construction example] The flood-prevention sheet of the present invention can be used to prevent flooding from openings in buildings caused by river overflows due to torrential rains. An example of this method will be described below with reference to the drawings.

[0052] Flooding into buildings such as houses occurs when water seeps in through gaps between doors and door frames, walls, floors, etc., that occur when opening and closing mechanisms such as front doors are closed. Therefore, it is necessary to seal these gaps. For example, as shown in Figure 2, by closing the front door 6 of a building and attaching the adhesive layer 9 of the water intrusion prevention sheet 8 of the present invention to the gap 7 between the door and the door frame, wall, floor, etc., from the inside so as to provide a liquid-tight seal, it is possible to prevent water from entering from outside the building.

[0053] As shown in Figure 3, by attaching the adhesive layer side 12 of the water ingress prevention sheet 11 of the present invention to the gap portion 10, similar to that described above, from the outside to provide a liquid-tight covering, it is also possible to prevent water from entering from outside the building.

[0054] Furthermore, by leaving the building's entrance door 13 open and attaching the adhesive layer of the water-prevention sheet 14 of the present invention to the door (Figure 4-1), and then closing the door, the water-prevention sheet can be tucked into the gap between the door and the door frame, wall, floor, etc., creating a liquid-tight installation (Figure 4-2), thereby preventing water from entering from outside the building.

[0055] When multiple flood-proof sheets are laid side by side to tightly cover the gaps, by butting the edges of adjacent flood-proof sheets together without any gaps and ensuring there are no overlapping sections, it is possible to prevent water from seeping in through gaps between the sheets, through steps caused by overlapping sheets, and through gaps between doors and door frames, walls, floors, etc.

[0056] The water-repellent sheet of the present invention can prevent water ingress simply by adhering its adhesive layer to the target area in a liquid-tight manner, and does not require the preparation of any other components. However, if the surface to be adhered, such as a door surface, is dirty with dust or other debris, wiping it clean before applying the water-repellent sheet of the present invention will allow it to exert its full adhesive strength, making water ingress prevention more reliable. Furthermore, this helps to suppress soiling of the water-repellent sheet of the present invention, making it suitable for reuse.

[0057] After the risk of flooding has passed, the flood-preventing sheet of the present invention, which is attached to doors, etc., can be peeled off, rolled up with the adhesive layer facing inward, and stored compactly with the adhesive layer surface attached to the base layer surface. This protects the adhesive layer surface from dirt and scratches, and allows for reuse when a new risk of flooding occurs. If dust or sand adheres to the adhesive layer and its adhesive strength decreases, it can be washed with water or a neutral detergent, wiped thoroughly to restore its adhesive strength, and then stored for immediate reuse in an emergency. [Examples]

[0058] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, "parts" refers to parts by mass.

[0059] [Creating the base layer] An elastomer, specifically silicone rubber (liquid silicone KE-1950-60-A / B, an addition-curing type silicone rubber composition manufactured by Shin-Etsu Chemical Co., Ltd.), was applied to both sides of a fiber cloth (0.22 mm thick, density: 19 threads / 25 mm vertically, 19 threads / 25 mm horizontally, tensile strength: 450 N / 25 mm vertically, 350 N / 25 mm horizontally, plain weave glass cloth) using a coating molding method. The cloth was then heated and cured in a vulcanizing furnace at 120°C for 15 minutes to obtain a base layer in which the fiber cloth was embedded in the vulcanized elastomer. Base layers A to C were obtained, with the average thickness and the ratio of the fiber cloth thickness to the base layer thickness as shown in Table 1 below.

[0060] [Table 1]

[0061] [Preparation of Silicone Adhesive Composition A] On the other hand, component (A-1) is 98 parts of dimethylpolysiloxane (A1) with a viscosity of 100 Pa·s at 25°C, with both ends sealed with dimethyl vinylsiloxy groups, and component (A-2) is a dimethylpolysiloxane with a kinematic viscosity of 5,000 mm at 25°C, with both ends sealed with dimethyl vinylsiloxy groups. 2One part of dimethylpolysiloxane (A2) at 1 / s and a kinematic viscosity of 1,000 mm² at 25°C, with both ends sealed with dimethyl vinylsiloxy groups. 2 (A3) 1 part of dimethylpolysiloxane (A3) / s, (B) component is (CH2=CH)(CH3)2SiO2, which is solid at 25°C. 1 / 2 Unit: (CH3)3SiO 1 / 2 Units and SiO 4 / 2 (B1) is a resinous organopolysiloxane (CH2=CH)(CH3)2SiO2 1 / 2 Unit: +(CH3)3SiO 1 / 2 Unit) / SiO 4 / 2 A 50% by mass toluene solution containing 33 parts of [unit (molar ratio) = 0.85, vinyl group content: 0.08 mol / 100 g] was placed in a stirring mixer and mixed for 30 minutes, after which the toluene was completely removed by distillation. To 100 parts of this silicone base, (CH3)3SiO was added as the crosslinking agent, which is component (C). 1 / 2 Unit: (CH3)2HSiO 1 / 2 Units, and SiO 4 / 2 1.2 parts of a resinous organohydrogenpolysiloxane (C1) having hydrosilyl groups consisting of units (hydrosilyl group amount 0.009 mol / g) (the ratio of the amount of hydrosilyl groups in component (C) to the amount of alkenyl groups in components (A) and (B) is 0.37) and 0.1 parts of ethynylcyclohexanol as a reaction control agent were added, and stirring was continued for 15 minutes to obtain silicone rubber composition A. 0.2 parts of platinum catalyst (Pt concentration 1% by mass) were mixed with this silicone rubber composition A to obtain silicone adhesive composition A.

[0062] [Preparation of Silicone Adhesive Composition B] (A-1) Component: 97 parts of the dimethylpolysiloxane (A1), (A-2) Component: a material with a kinematic viscosity of 600 mm at 25°C, with both ends sealed with dimethyl vinylsiloxy groups. 2A 50% by mass toluene solution containing 3 parts of dimethylpolysiloxane (A4) at 1 / s and 33 parts of the resinous organopolysiloxane (B1) as component (B) was placed in a stirring mixer and mixed for 30 minutes. After mixing, the toluene was completely removed to prepare a silicone base. To 100 parts of this silicone base, 1.3 parts of the resinous organohydrogenpolysiloxane (C1) as a crosslinking agent (component (C) was 0.40, with the ratio of hydrosilyl groups in component (C) to alkenyl groups in components (A) and (B) being 0.40) and 0.1 parts of ethynylcyclohexanol as a reaction control agent were added, and stirring was continued for 15 minutes to obtain silicone rubber composition B. 0.2 parts of platinum catalyst (Pt concentration 1% by mass) was mixed with this silicone rubber composition B to obtain silicone adhesive composition B.

[0063] [Preparation of Silicone Adhesive Composition C] A 50% by mass toluene solution containing 98 parts of dimethylpolysiloxane (A1) as component (A-1), 2 parts of dimethylpolysiloxane (A2) as component (A-2), and 50 parts of the resinous organopolysiloxane (B1) as component (B) was placed in a stirring mixer and mixed for 30 minutes. After mixing, the toluene was completely removed to prepare a silicone base. To 100 parts of this silicone base, 1.5 parts of the resinous organohydrogenpolysiloxane (C1) as a crosslinking agent (component C) was added (the ratio of the amount of hydrosilyl groups in component (C) to the amount of alkenyl groups in components (A) and (B) was 0.32), and 0.1 parts of ethynylcyclohexanol as a reaction control agent was added. Stirring was continued for 15 minutes to obtain silicone rubber composition C. 0.2 parts of platinum catalyst (Pt concentration 1% by mass) was mixed with this silicone rubber composition C to obtain silicone adhesive composition C.

[0064] [Preparation of Silicone Adhesive Composition D] A 50% by mass toluene solution containing 98 parts of dimethylpolysiloxane (A1) as component (A-1), 1 part of dimethylpolysiloxane (A2) and 1 part of dimethylpolysiloxane (A3) as component (A-2), and 25 parts of the resinous organopolysiloxane (B1) as component (B) was placed in a stirring mixer and mixed for 30 minutes. After mixing, the toluene was completely removed to prepare a silicone base. To 100 parts of this silicone base, 1.1 parts of the resinous organohydrogenpolysiloxane (C1) as a crosslinking agent (component (C) was 0.44, with the ratio of hydrosilyl groups in component (C) to alkenyl groups in components (A) and (B) being 0.44) and 0.1 parts of ethynylcyclohexanol as a reaction control agent were added, and stirring was continued for 15 minutes to obtain silicone rubber composition D. 0.2 parts of a platinum catalyst (Pt concentration 1% by mass) was mixed with this silicone rubber composition D to obtain a silicone adhesive composition D.

[0065] [Preparation of Silicone Adhesive Composition E] A 50% by mass toluene solution containing 50 parts of dimethylpolysiloxane (A1) as component (A-1), 50 parts of dimethylpolysiloxane (A3) as component (A-2), and 33 parts of the resinous organopolysiloxane (B1) as component (B) was placed in a stirring mixer and mixed for 30 minutes. After mixing, the toluene was completely removed to prepare a silicone base. To 100 parts of this silicone base, 3.0 parts of the resinous organohydrogenpolysiloxane (C1) as a crosslinking agent (component C) (the ratio of the amount of hydrosilyl groups in component (C) to the amount of alkenyl groups in components (A) and (B) is 0.85) and 0.1 parts of ethynylcyclohexanol as a reaction control agent were added, and stirring was continued for 15 minutes to obtain silicone rubber composition E. 0.2 parts of platinum catalyst (Pt concentration 1% by mass) was mixed with this silicone rubber composition E to obtain silicone adhesive composition E.

[0066] [Preparation of Silicone Adhesive Composition F] A 50% by mass toluene solution containing 100 parts of the dimethylpolysiloxane (A1) as component (A-1) and 10 parts of the resinous organopolysiloxane (B1) as component (B) was placed in a stirring mixer and mixed for 30 minutes. After mixing, the toluene was completely removed to prepare a silicone base. To 100 parts of this silicone base, 8.0 parts of a linear dimethylsiloxane-methylhydrogensiloxane copolymer (degree of polymerization 18, SiH group content 0.0013 mol / g) (C2) with dimethylhydrogensiloxy groups sealed at both ends was added as a crosslinking agent (the ratio of the amount of hydrosilyl groups in component (C) to the amount of alkenyl groups in components (A) and (B) was 0.96), and 0.1 parts of ethynylcyclohexanol was added as a reaction control agent. Stirring was continued for 15 minutes to obtain silicone rubber composition F. 0.2 parts of a platinum catalyst (Pt concentration 1% by mass) was mixed with this silicone rubber composition F to obtain a silicone adhesive composition F.

[0067] [Example 1] The above-mentioned silicone adhesive composition A was laminated onto the substrate layer A using a comma coater to a thickness of 1.0 mm, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.45 mm. The adhesive surface of the above-mentioned adhesive layer is protected by attaching a 38 μm thick polyethylene terephthalate resin film (acrylic-treated PET) that has been treated with an acrylic release agent.

[0068] [Example 2] The above-mentioned silicone adhesive composition B was laminated onto the substrate layer B using a comma coater to a thickness of 2.0 mm, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 3.0 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0069] [Example 3] The above-mentioned silicone adhesive composition C was laminated onto the substrate layer C using a comma coater to a thickness of 1.5 mm, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.8 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0070] [Example 4] On the substrate layer A described above, the side opposite to the side on which the adhesive layer is laminated was subjected to plasma treatment using an atmospheric pressure plasma generator under the following conditions: plasma treatment speed 10-100 mm / s, power supply: 200VAC (30A), compressed air: 0.5 MPa (1 NL / min), 20 kHz / 300 W, irradiation time: 20 seconds. After that, a silicone release agent for silicone adhesives containing a fluoroalkyl group was applied to the surface of the substrate layer as a toluene diluted solution, air-dried, and then heated to completely volatilize and cure the organic solvent, thereby performing a release treatment. Furthermore, the adhesive layer laminated surface of the obtained substrate layer was subjected to plasma treatment using an atmospheric pressure plasma generator under the same conditions as above. A plasma-treated substrate layer A was coated with the above-mentioned silicone adhesive composition D to a thickness of 1.0 mm using a comma coater, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.45 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0071] [Comparative Example 1] As a base rubber, 100 parts of millable-type dimethyl silicone rubber compound KE-571-U (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a transparent, uncrosslinked dimethyl silicone rubber compound, to which 0.5 / 2.0 parts each of addition (hydrosilylation) reaction vulcanizing agent C-25A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) were added and kneaded using a double roll to obtain a dimethyl silicone rubber composition. This composition was then formed into a 0.7 mm thick sheet on a 100 μm textured PET film by calendering, and subsequently heated and cured in a heating furnace at 140°C for 10 minutes to obtain a sheet in which a base layer D was laminated on the PET film. The above-mentioned silicone adhesive composition A was laminated onto the substrate layer D using a comma coater to a thickness of 1.0 mm, and after heating and curing in a heating furnace at 120°C for 10 minutes, the PET film was peeled off to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.7 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0072] [Comparative Example 2] The above-mentioned silicone adhesive composition E was laminated onto the above-mentioned substrate layer A using a comma coater to a thickness of 1.0 mm, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.45 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0073] [Comparative Example 3] The above-mentioned silicone adhesive composition F was laminated onto the above-mentioned substrate layer A using a comma coater to a thickness of 1.0 mm, and then heated and cured in a heating furnace at 120°C for 10 minutes to produce a water-resistant sheet. The average thickness of the obtained water-resistant sheet was 1.45 mm. The adhesive surface of the above-mentioned adhesive layer was protected by attaching a resin film similar to that in Example 1.

[0074] [Comparative Example 4] A 2mm thick sheet, in which polyester resin fiber cloth was embedded in polyvinyl chloride resin, was laminated with a 0.1mm thick acrylic adhesive tape without a base material to create a water-resistant sheet. The average thickness of the resulting water-resistant sheets was 2.1mm.

[0075] [Evaluation criteria] The following evaluations were performed on the flood prevention sheets of Examples 1-4 and Comparative Examples 1-4 described above. The results are shown in Table 2.

[0076] [Hardness of the adhesive layer] The hardness of the adhesive layer of the obtained water-repellent sheet was measured using a CSR2 type Asker rubber hardness tester (manufactured by Polymer Instruments Co., Ltd.). The hardness was measured 5 seconds after the base of the hardness tester made contact with the adhesive layer.

[0077] [Adhesive strength] A 130 μm thick polyethylene terephthalate film (product name: Matt Lumirror #125, manufactured by Kimoto Co., Ltd.), with one side roughened by sandblasting (surface roughness Ra 0.7 μm), was attached to a SUS plate so that the matte side was facing outwards. This was prepared as the substrate for the adhesive layer. A waterproof sheet was cut to a width of 25 mm and a length of 200 mm to serve as a test sample. The adhesive layer was attached to the matte side of the polyethylene terephthalate film, and after pressing with a roller five times with a load of 2 kg, a 180° peel test was performed within 5 minutes at a peeling speed of 300 mm / min to measure the adhesive strength.

[0078] [Water ingress prevention performance test] A water ingress prevention performance test was conducted in accordance with JIS A4716:2019 and the Japan Building Materials Testing Center (JSTM) K6401-1. A water ingress prevention performance test apparatus was constructed using an 800mm wide aluminum alloy door 15 with a door frame and a water tank 16 on the side corresponding to the exterior of the door. The appearance of the test apparatus is shown in Figure 5. In Figure 5, the front is the exterior side and the back is the interior side. With the door closed, a 150mm wide x 900mm wide water ingress prevention sheet 17 was attached from the interior side of the door so that the width direction was the height direction (Figure 6), and the test was conducted with a watertight height of 85mm. Good water ingress prevention was marked with ◎, and significant water ingress was marked with ×.

[0079] [Direct winding test] The resin film attached to the adhesive layer of the waterproof sheet was peeled off, and the waterproof sheet was rolled up with the adhesive layer facing inward. After storage at 40°C for 30 days, the state of unrolling the sheet and whether the adhesive layer had migrated to the surface of the base material layer or whether there was any damage were evaluated. ◎ was used to indicate good results in all aspects, △ for heavy unrolling, and × for partial migration of the adhesive layer to the surface of the base material layer.

[0080] [Damage to door paint during peeling] Sample pieces of wooden entrance doors painted with various types of paint were prepared, a water-repellent sheet was attached, and after one week, the paint peeling was visually evaluated after peeling at a rate of 300 mm / min in a 180° direction according to the method described in JIS Z0237:2009. A ◎ was used to indicate that there was no paint peeling and no damage, and a × was used to indicate that some of the paint had peeled off.

[0081] [Washability, Restoration rate of adhesive strength after washing] A waterproof sheet, soiled with sand attached to its adhesive layer, was washed with water using a sponge and neutral detergent. The cleanability of the sheet was visually evaluated to determine if the sand could be removed. A score of ◎ was used to indicate that no sand residue remained, and a score of × indicated that some residue remained. Furthermore, after the above-mentioned cleaning and wiping off the water, the adhesive strength of the water-resistant sheet was measured by performing the above-mentioned 180° peel test, and the ratio of this to the adhesive strength before soiling (measured in the above-mentioned adhesive strength evaluation) was defined as the post-cleaning adhesive strength recovery rate. Adhesion recovery rate after cleaning = Adhesion after cleaning / Adhesion before soiling

[0082] [Tear test] The tear strength of the base material layer of the water-repellent sheet was measured using a crescent-shaped test specimen in accordance with JIS K6252-1:2015. For Comparative Example 4, the test specimen did not tear under the same test conditions, so no measurement results were obtained.

[0083] [Table 2] In the table, H / Vi represents the molar ratio of hydrosilyl groups in component (C) to the total amount of alkenyl groups in components (A) and (B).

[0084] As is clear from the results in Table 2, the flood-prevention sheets of Examples 1 to 4, which are within the scope of the present invention, exhibit excellent performance in preventing flooding from openings in buildings, can be easily peeled off after use, can be stored compactly, and can be easily reused when flooding is expected. On the other hand, the water-resistant sheet of Comparative Example 1 lacked a fibrous fabric in its base layer, resulting in insufficient tear strength in the base layer and a risk of damage during use. The water-resistant sheet of Comparative Example 2 had a weak adhesive strength of less than 2N / 25mm in its adhesive layer, resulting in poor adhesion to the surface to which it was attached and insufficient water-resistant performance. Conversely, the water-resistant sheet of Comparative Example 3 had an adhesive strength exceeding 10N / 25mm in its adhesive layer, which was too strong and damaged the paint on the surface to which it was attached. Furthermore, when it was peeled from the surface to which it was attached and rolled up with the adhesive layer facing inward so that the adhesive layer surface was in direct contact with the surface of the base layer, the adhesive layer stuck to the base layer when it was reused, making it difficult to unroll. Moreover, cleaning and regeneration became difficult when foreign matter adhered to the adhesive layer and the adhesive strength decreased. The water-resistant sheet of Comparative Example 4, which was outside the scope of the present invention, was significantly inferior to the present invention in all evaluation results. [Explanation of Symbols]

[0085] 1. Textile fabric 2. Cured product of silicone rubber composition 3 Base material layer 4 Adhesive layer 5. Flood prevention sheet 6. Entrance door 7. Gap 8. Flood prevention sheet 9 Adhesive layer side 10 Gap 11. Flood prevention sheet 12 Adhesive layer side 13. Entrance door 14. Flood prevention sheet 15 Aluminum alloy doors 16 Aquariums 17 Flood prevention sheet

Claims

1. A water-preventing sheet for preventing water from seeping into the interior of a building, comprising a base layer in which a fiber cloth is embedded in a vulcanized elastomer, and an adhesive layer on one side of the base layer made of a cured silicone adhesive composition, The aforementioned silicone adhesive composition (A) A linear organopolysiloxane having alkenyl groups with 2 to 8 carbon atoms at both ends of the molecular chain, consisting of (A-1) and (A-2) below: 100 parts by mass (A-1) Alkenyl group-containing organopolysiloxane with a viscosity of 30 to 1,000 Pa·s at 25°C: 95.0 to 99.9% by mass (A-2) Alkenyl group-containing organopolysiloxane with a kinematic viscosity of 30 to 10,000 mm² / s at 25°C: 0.1 to 5.0% by mass (B) R 3 SiO 1 / 2 unit, R 1 R 2 SiO 1 / 2 unit, and SiO 4 / 2 unit Resinous organopolysiloxane consisting of (wherein R is independently an alkyl group having 1 to 6 carbon atoms, and R1 is an alkenyl group having 2 to 8 carbon atoms): 5 to 100 parts by mass (C) R 3 SiO 1 / 2 unit, R 2 HSiO 1 / 2 unit, and SiO 4 / 2 unit A resinous organohydrogenpolysiloxane consisting of the above formula (wherein R is the same as above): an amount such that the amount of hydrosilyl groups in component (C) is in the range of 0.2 to 1.0 moles relative to the total amount of alkenyl groups in component (A) and component (B): (D) Addition reaction catalyst: Catalytic amount This is an addition-curing type silicone adhesive composition containing, A water-prevention sheet characterized in that the adhesive strength of the adhesive layer is 2 to 10 N / 25 mm.

2. The water-repellent sheet according to claim 1, wherein the elastomer is one or more selected from the group consisting of silicone rubber, EPDM rubber, butyl rubber, chloroprene rubber, and natural rubber.

3. The water-repellent sheet according to claim 1, wherein the fiber cloth is a cloth woven from one or more fibers selected from the group consisting of glass fibers, carbon fibers, aramid fibers, and silicon carbide fibers.

4. The water-repellent sheet according to claim 1, wherein the thickness of the fiber cloth is 3 to 80% of the thickness of the base material layer.

5. The water-repellent sheet according to claim 1, characterized in that the surface of the base layer in contact with the adhesive layer is subjected to a dry surface modification treatment selected from the group consisting of plasma treatment, corona treatment, and ultraviolet irradiation treatment, or a primer treatment.

6. The water-repellent sheet according to claim 1, characterized in that a release treatment is applied to the surface of the base material layer opposite to the surface having the adhesive layer.

7. The water-resistant sheet according to claim 1, wherein a resin film is applied to the surface of the adhesive layer.

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