EP0757139A1

EP0757139A1 - Moisture-permeable composite sheet for water-proofing concrete

Info

Publication number: EP0757139A1
Application number: EP96902459A
Authority: EP
Inventors: Yoshihiro Chikamori; Satoshi Yamamoto
Original assignee: Japan Gore Tex Inc
Current assignee: Japan Gore Tex Inc
Priority date: 1995-02-17
Filing date: 1996-02-16
Publication date: 1997-02-05
Also published as: CN1150832A; JPH08218567A; WO1996025569A1; AU4676096A; CA2188016A1; EP0757139A4; AU691724B2

Abstract

Disclosed is a vapor-permeable and waterproof sheet to be applied to a concrete surface in waterproofing the surface of concrete.

This waterproof sheet has the structure such that a protective cloth is laminated on a one surface of a polymer film having water repellency and vapor permeability and fixed thereto by partial fusing or bonding and a lightweight and flexible sheet having a number of air-permeable pores is laminated on another surface of said polymer and fixed thereto by partialfusing or bonding.

Description

TECHNICAL FIELD

The present invention relates to a waterproof sheet useful for waterproofing surfaces of concrete covering roofs or outer walls of buildings and, more particularly, to a vapor-permeable and waterproof sheet for waterproofing concrete so adapted as to diffuse water vapors generated from the inside of the concrete to the outside due its vapor permeability, to fail to cause workers to bear too heavy physical load on account of its light weight, and to allow a ready adhesion with adhesive at construction sites because of its material configuration that can make sheets attach and adhere to each other readily.

BACKGROUND ART

A waterproof sheet for use in waterproofing surfaces of concrete are employed primarily for preventing rain water from leaking through cracks or the like created in surfaces of concrete into buildings by covering the concrete surfaces of roofs or outer walls of buildings. If a waterproof sheet would be made of a material that does not permeate vapor for the exclusive purpose to prevent the leakage of rain water, however, water vapor generated from the inside of the concrete cannot be diffused or spread into the outside, thereby causing the water vapor to be condensed into dew on and between surfaces of the concrete and the waterproof sheet. The dew may cause the waterproof sheet to become swollen or come off from the concrete surface and eventually iron reinforcing rods to rust away when the dew again queezes and penetrates into the inside of the concrete. Recently, therefore, a waterproof sheet for waterproofing concrete has been demanded to have the functions of permeating vapor or spreading water vapor into the air in the outside atmosphere as well as waterproofing ability.
The present invention relates to a vapor-permeable and waterproof sheet so adapted as to be employed for such a technical field as described hereinabove and it further provides the solution to the technical problems left unsolved by conventional the waterproof sheets, which involve making a waterproof sheet lightweight in order to provide a better attachment workability and improving attachment workability.
The following has been proposed so far as techniques for waterproofing concrete which take diffusion and removal of water vapor inside the concrete into consideration.
One of the waterproofing techniques comprises sticking an air permeable material such as a non-woven cloth or the like on a surface of concrete and further sticking a non-vapor-permeable rubber sheet for waterproofing on the outer surface of the air permeable material, followed by discharging vapor in a layer of the air permeable material by suction with a deairing device (such as a vacuum pump or the like). The discharge of the water vapor generated from the inside of the concrete to the outside with such a deairing device by this process is theoretically possible; however, this technique generally requires a long deairing step and it cannot actually achieve effects of deaeration as expected. Further, it requires additional equipment such as a deairing device and it can be easily anticipated that building and running costs become expensive. Furthermore, it suffers from the problem from the point of view of management that continual maintenance and inspection are also required. In addition, the use of a waterproofing rubber sheet presents the defects that the sheet is very heavy in itself and it imposes a too heavy burden upon workers.
A process using a waterproofing porous sheet is also proposed (in the Official Gazette of Japanese Utility Model Publication No. 63-15,471), which involves sticking a non-vapor-permeable rubbery sheet on a surface of concrete, forming at least one through hole (a permeable hole) in the rubbery sheet, covering the through hole portion with an oriented polytetrafluoroethylene film or a composite film consisting of an oriented polytetrafluoroethylene film with a fiber material, and allowing the rubbery sheet to adhere to the oriented polytetrafluoroethylene film or the composite film in a liquid tight manner by the action of adhesion, fusion or the like. This process, however, presents the problem that it actually is very difficult to let the rubbery sheet adhere to the oriented polytetrafluoroethylene film or the fiber material in a liquid tight way. Further, as it is well known that polytetrafluoroethylene is a material very poor in adhesion in itself in joining the polytetrafluoroethylene film to the rubbery sheet, it can be said to be almost impossible to achieve a reliable and liquid tight adhesion by simplified adhesion processing at building sites. In instances where the fiber material is to be joined to the rubbery sheet, the presence of a layer of the fiber material causes the problem with adhesion by adhesive. The reason is because the layer of the fiber material rich in pores absorb the adhesive, thereby failing to provide a liquid-tight adhesion unless a considerably strong compression force should be continued to be applied until a sufficient tack can be gained. Therefore, it is extremely difficult in this case, too, to provide a reliably liquid-tight adhesion by simplified adhesion processing at building sites. Given this, the conventional method adopts convenient procedure in which a part (hereinafter referred to as a deairing disk) prepared in plants in advance by batch processing by integrating a composite film of the oriented polytetrafluoroethylene film and the fiber material with a rubbery frame are mounted on a waterproof sheet so as to cover its hole at building sites and the rubbery frame of this part is then attached to the rubbery sheet with adhesive. This procedure, however, presents the difficulties that manufacturing and constructing costs per one deairing portion become too expensive and a number of mounting portions is limited for that reason. As a result, the problem may arise that no sufficient effect can be achieved for discharging water vapor. Further, as long as a waterproofing rubbery sheet is still used, the problem with imposing too heavy load upon workers remains unsolved yet because the rubbery sheet is very heavy.
A process for joining a vapor-permeable' and waterproof sheet to a surface of concrete is also proposed (as in Japanese Utility Model Publication No. 4-45,872), the vapor-permeable and waterproof sheet being prepared by laminating a cushioning material having air permeability and flexibility with a surface material consisting of a porous polytetrafluoroethylene film by partially bonding and fixing them to each other. This process can be said to ensure a sufficient level of vapor permeability as well as sufficient waterproofing performance because the water-repellent polymer film bears the waterproofing function and the porous film ensures permeability of water vapor over the entire area of the waterproof sheet. The vapor-permeable and waterproof sheet to be used for this process may be a laminated sheet having a two-ply structure with the cushioning material having air permeability and flexibility laminated on the porous polytetrafluoroethylene film or a laminated sheet having a three-ply structure with a protective layer consisting of a fiber material laminated on the two-ply laminated sheet on the side of the porous polytetrafluoroethylene film. This embodiment of the waterproof sheet fails to become too heavy so that it can solve the problem of weight of the waterproof sheet that may impose too heavy load upon workers. The waterproof sheet of this type having the polytetrafluoroethylene film disposed on its outermost side, however, may actually be encountered with the difficulty in sustaining the initially expected level of waterproofing performance in construction environment because the polytetrafluoroethylene film may often be damaged with foreign materials such as sands or small pieces of stones. Further, the liquid-tight adhesion with adhesive to be made for the purpose to attach and join the sheets to each other may cause the problem at construction sites as long as the waterproof sheet has the material configuration as described hereinabove, even if it would be made by superimposing one sheet upon another or attaching a one side of one the waterproof sheet face to face to a one side of another waterproof sheet.
When there is used the sheet having the three-ply structure with the protective layer of the fiber material disposed as its outermost layer, the probability at which the polytetrafluoroethylene film is damaged by foreign materials can be made lower, but the presence of the layer of the fiber material may cause the problem, too, in joining the sheets to each other in a waterproof way.
The vapor-permeable and waterproof sheet according to the present invention uses a flexible and lightweight sheet having a large number of air-permeable pores as a protective layer, in place of the protective layer of the fiber material layer to be used for the conventional vapor-permeable and waterproof sheet having the three-ply structure. This arrangement can provide the present invention with a solution to the problems inherent in the conventional waterproof sheets that it is difficult to attach and bond them to each other in a liquid-tight fashion, while the waterproof sheet of the present invention sustains a vapor-permeable function and a lightweight property as a whole. In other words, the present invention can provide a solution to the long-lasting technical demand to readily allow a waterproofing adhesion and bonding of the sheets to each other at construction sites.

DISCLOSURE OF INVENTION

As a result of extensive studies, it has been found that a composite sheet having a three-ply structure can achieve the objects as described hereinabove, the composite sheet being structured in such a way that a polymer film having water-repellent and vapor-permeable abilities, as illustrated by a porous polytetrafluoroethylene film, is laminated on its one surface with a protective cloth having air permeability and cushioning performance and on its other with a lightweight and flexible sheet having a great number of air-permeable pores and fixed to the protective cloth and the sheet with their laminated surfaces partially bonded or fused. The present invention has been completed on the basis of this finding.
The present invention provides a vapor-permeable composite sheet for waterproofing concrete, which is characterized by the structure in which a polymer film having water-repellent and vapor-permeable abilities is laminated on its one surface with a protective cloth having air permeability and cushioning performance by partial bonding or partial fusing, and it is further laminated on its other with a lightweight and flexible sheet having a great number of air-permeable pores and fixed to the protective cloth and the sheet by partial bonding or partial fusing.
The vapor-permeable and waterproof sheet according to the present invention comprises three materials each in a sheet or membrane form having air permeability or vapor permeability in its entirety or in parts and it is structured in such a manner that all the layers are laminated together with each gap between the layers bonded together by the process that does not adversely affect the air permeability or vapor permeability of each material (by partial bonding or fusing) . With this structure, the waterproof sheet has water permeability or vapor permeability as a whole.
The vapor-permeable and waterproof sheet according to the present invention can provide a sufficient level of protection for the polymer film having water-repellency and vapor permeability because the polymer film having water-repellency and vapor permeability can be prevented from being damaged by foreign materials, such as small stone or sands, which may enter a gap between the concrete surface and the waterproof sheet at the time of execution as well as the impact from the outside can be alleviated by attaching the side of the protective cloth having air permeability and cushioning performance to the side of the concrete surface. Further, even if the concrete surface would be cracked, the protective cloth cannot be broken due to its elastic ability, thereby enabling a prevention of break of the vapor-permeable and waterproof sheet or a prevention of separation of the bonded surfaces between the vapor-permeable and waterproof sheet and the concrete surface.
The vapor-permeable and waterproof sheet according to the present invention can prevent damages of its middle sheet layer against impact from the outside or by foreign materials by laminating a lightweight and flexible water-resistant sheet having a large number of air-permeable pores as an outermost layer (on the side opposite to the protective cloth surface), while sustaining the air-permeable or vapor-permeable function of the vapor-permeable and waterproof sheet as a whole and contributing toward making the vapor-permeable and waterproof sheet lightweight. Further, the vapor-permeable and waterproof sheets according to the present invention can readily be attached and bonded to each other with adhesive in a waterproofing manner. Even if this lightweight and flexible sheet little has air permeability or vapor permeability, however, that the air permeability or vapor permeability of the vapor-permeable and waterproof sheet as a whole is impaired to a great extent can be avoided by providing the sheet with a large number of air-permeable pores.
It is to be noted herein that such air-permeable pores be formed each independently from the others and they are not connected to each other in the plane direction of the sheet, thereby failing to impair waterproofing capabilities at its connecting portion.
The following is a description of the vapor-permeable and waterproof sheet according to the present invention in more detail.
The vapor-permeable and waterproof sheet according to the present invention is structured in such a manner that a protective cloth (1c) having air permeability and cushioning performance is laminated on a one surface of a polymer film (1b) having water-repellency and vapor permeability and fixed thereto by partial bonding or partial fusing and a lightweight and flexible sheet (1a) having a large number of air-permeable pores is laminated on the other surface thereof and fixed thereto by partial bonding or partial fusing.
As the polymer film (1b) having water-repellency and vapor permeability which constitutes a structuring material layer of the vapor-permeable and waterproof sheet according to the present invention, there may be used a polymer film comprising a polymer compound of a polyolefinic type, a polyurethane type, a polyester type, a polyvinyl chloride type, a cellulosic type, a fluorine-containing polyolefinic type or the like. Although the polymer film is not required to be porous, it is preferred that it is a porous film from the point of view of ensuring a great extent of air permeability or vapor permeability. Further, it is desired from the point of view of preventing penetration of water that its water-repellency has at least 90° or more, when determined as a contact angle of a water drop. In each case, there may appropriately be used any polymer film having any chemical composition, whether it is porous or non-porous, as long as it can ensure water-repellency to such an extent to which it can prevent penetration of water as well as a required level of vapor permeability can be gained.
As the particularly preferred polymer films having water-repellency and vapor permeability, there may be mentioned polymer films of a fluorine-containing polyolefinic type. Among those, porous polytetrafluoroethylene films are preferred and porous polytetrafluoroethylene films having flexibility, as referred to as oriented polytetrafluoroethylene films, are more preferred.
The oriented polytetrafluoroethylene films are so-called polytetrafluoroethylene films which may be prepared by orienting a paste product obtained by extruding polytetrafluoroethylene fine powder consisting of a mixture of polytetrafluoroethylene with a lubricating aid. Polytetrafluoroethylene is well known as a material having extremely chemical stability and superior in weathering, resistance to ultraviolet rays, resistance to hot and cold temperatures, water resistance, water repellency and so on. Hence, it is a material very suitable for usage required to sustain waterproofing and vapor permeable performance over a long period of time for a product, such as a waterproof sheet for water-proofing concrete.
A preferred range of a film thickness of the porous polytetrafluoroethylene films or the oriented polytetrafluoroethylene films to be used for the vapor-permeable and waterproof sheet of the present invention may be from 3 to 300 µm as an average film thickness, preferably from 10 to 150 µm and more preferably from 20 to 100 µm, from the point of view of providing the waterproof sheet with flexibility, when measured by a dial gauge (1/1,000 mm dial thickness gauge; manufactured by Techlock; measured in a state in which no load other than the spring load of the main body is applied). If the average film thickness of the polytetrafluoroethylene film would be thinner than 3 µm, mechanical durability cannot be gained at a sufficient level and, in addition, laminating procedures may become difficult. Conversely, if the average film thickness thereof would exceed 300 µm, productivity becomes worse and costs become impractical because such material becomes too expensive. Given a balance among durability, water resistance, productivity and costs, it is preferred to set the film thickness of the film in the range of from 10 to 150 µm as an average film thickness. Further, with the provision of flexibility taken into account, it is more preferred to set the film thickness of the film in the range of from 20 to 100 µm as an average film thickness.
When the porous polytetrafluoroethylene films or oriented polytetrafluoroethylene films are specified from their pore sizes, any polytetrafluoroethylene film may be used for the purpose of the present invention as long as the maximum pore sizes may be within the range of from 0.01 to 10 µm, when measured by bubble point method (ASTM F-316). When a balance between vapor permeability and water resistance is taken into account, the range of the maximum pore sizes may be preferably from 0.05 to 5 µm and, more preferably, from 0.1 to 3 µm. If the maximum pore size would be less than 0.01 micron, the film cannot provide a sufficient degree of vapor permeability. On the contrary, if the maximum pore size would be greater than 10 µm, a surface level of water resistance cannot be gained. Given a balance among vapor permeability, water resistance and durability, it is most appropriate to set the maximum pore sizes to be within the range of from 0.1 to 3 µm. In either case, what is greatly significant is that a speed of permeating vapor is more important than the length of the pore size and it is desired that the speed of permeating vapor is at least 500 grams per square meter per 24 hours or higher, when measured by the method in accordance with JIS L1099 B-2.
Then, a description will be made of the protective cloth (1c) having air permeability and cushioning performance as one of the structuring material layers for the vapor-permeable and waterproof sheet of the present invention. As the protective cloth (1c), any woven cloth, knitted cloth, non-woven cloth or any other product made of polymer fibers may be used for this purpose as long as they sustain air permeability and cushioning performance to a sufficient extent and there may be mentioned any one of a polyolefinic type, a polyurethane type, a polyester type, a nylon type, a polyvinyl alcohol type, an acrylic type, a fluorocarbon type or the like. They may be employed singly or in combinations thereof. A thermoplastic polymer of a polyolefinic type, a nylon type, a vinyl chloride type or the like is preferred in order to ensure adhesion or fusion performance between the waterproof sheets as a product. Whichever is more suitable among woven cloth, knitted cloth and non-woven cloth may be appropriately selected on the basis of environment of use or purposes of use. In this sense, non-woven cloth can be said to take a preferred status as a material because it is high in air permeability and cushioning performance and it is plenty of kinds to be selected and reasonable in price. Further, non-woven cloth made of, for example, polyethylene, polypropylene, nylon, polyester or polyvinyl alcohol is preferred.
The average film thickness of the protective cloth may be preferably from 1 to 20 mm, more preferably from 0.3 to 10 mm. If the average film thickness would be less than 0.1 mm, the cushioning function for the protective cloth cannot be expected to a sufficient extent. Conversely, if the average film thickness thereof would be thicker than 20 mm, it is not appropriate to use such a protective cloth because productivity may become poor, costs may become expensive and, further, a waterproof sheet resulting from the such protective cloth may become heavy as a whole. Accordingly, with a balance of these factors, the most preferred range of the average film thickness of the protective cloth may be said to be from 0.3 to 10 mm.
Further, a description will be made of the lightweight and flexible sheet (1a) having a large number of air-permeable pores as one of the structuring material layers of the vapor-permeable and waterproof sheet according to the present invention. As the lightweight and flexible sheet (1a), there may appropriately be used any water-resistant and non-porous material shaped in the form of a sheet and having no continuous pores. It is further preferred that such a material has some degree of cushioning ability in order to protect the vapor-permeable polymer film. In addition, it is preferred that a material is low in weight per unit area in order to sustain lightweight properties. Furthermore, thermally insulating properties are preferred properties to be provided for the sheet. From these points of view, the sheet is desired to be a closed-cell foam sheet. The material of the closed-cell foam sheet is not limited to a particular one as long as the above-mentioned properties can be ensured. It may preferably include, for example, one made of a polyethylene, a polypropylene, a polybutene, a polyvinyl acetate, a polyethyl acrylate, a polyacrylate or the like and it may be used singly or in combinations of two or more. Among those, the closed-cell foam sheet made of polyethylene or polypropylene is particularly preferred in terms of cushioning ability, thermally insulating properties, density, weathering, costs and so on.
The thickness of the closed-cell foam sheet may be in the range of from 1 to 50 mm, more preferably from 2 to 35 mm. If the thickness thereof would be less than 1 mm, then cushioning ability and thermally insulating properties may become insufficient. On the contrary, if the thickness thereof would exceed 50 mm, it is not preferred because flexibility and portability become poor and its weight becomes heavier. Further, the foaming magnification of the closed-cell foam may be in the range of from 5 to 50 times, more preferably from 10 to 40 times. If the foaming magnification thereof would be too low, then the resulting closed-cell foam may become too stiff. On the other hand, if the foaming magnification thereof would be too high, the manufacturing of the closed-cell foam becomes difficult and the resulting closed-cell foam may become difficult to handle. With these matters taken into account, it is preferred that the foaming magnification of the closed-cell foam sheet be set within the range of from 10 to 40 times.
As the process for providing the closed-cell foam sheet with air-permeable pores, there may be used any process known to the art as long as such air-permeable pores can be formed in the closed-cell foam sheet. In usual cases, there may be used the process comprising punching the closed-cell foam sheet with air-permeable pores formed therethrough after the sheet was prepared from the closed-cell foam. Although the area of the air-permeable pores, shape, pitch, density, distribution and so on are not limited to particular ones, it can be noted here that if a rate of the area of the pore portion is too small, on the one hand, a sufficient degree of vapor-permeable performance may not be gained and if a rate of the area of the pore portion is too large, on the other hand, the intensity and core of the closed-cell foam sheet may become so weak that the adhesion by laminating is made difficult. Therefore, it is desired to set the area of the pore portion thereof within the range of from 0.001% to 40%, more preferably from 0.1% to 20%.
In accordance with the present invention, the protective cloth (1c) having air permeability and cushioning performance and the lightweight and flexible sheet (1a) having a large number of air-permeable pores are laminated on the respective surfaces of the polymer film (1b) having water repellency and vapor permeability and fixed thereto by partial bonding or partial fusing. The reason for adopting the partial bonding or partial fusing technique is because air permeability and vapor permeability of the vapor-permeable polymer film may be impaired if they would be bonded or fused over their entire areas.
As a process for joining, there may be mentioned a variety of processes such as adhesion with adhesive, fusion with heat or high frequency. For the present invention, any process may be appropriately selected as long as it can provide a sufficient degree of bonding as well as water resistance and weathering can be gained to an adequate extent. As the waterproof sheet for concrete is required to sustain durability for a long period of time, thermal fusion is the most preferred joining process.
By the term partial bonding is intended herein to be meant a bonding technique for laminating films and bonded to each other by partially coating the surfaces thereof with adhesive, for example, in spot-like, linear, lattice or pattern form.
For the adhesion of the protective cloth (1c) having air permeability and cushioning ability to the vapor-permeable polymer film (1b) and for the adhesion of the lightweight and flexible sheet (1a) having a large number of air-permeable pores to the vapor-permeable polymer film (1b), there may be applied any coating pattern of the adhesive such as coating in spot-like, linear, lattice-shaped or pattern form for the former, while for the latter it is desired to apply a continuous coating pattern such as in linear, lattice-shaped or pattern form except for a coating pattern in spot-like form. The reason is because, if the adhesive would be coated in spot-like state, rain water leaked from an air-permeable pore portion may penetrate into a gap at the adhesion point of the boundary surface portion between the vapor-permeable polymer film (1b) and the porous sheet (1a) eventually reach the bonded portion between the waterproof sheets (1), thereby causing the risk that the rain water enters into the inside of the waterproof sheet. These can be likewise said of the partial fusion.
When the vapor-permeable polymer film (1b) is bonded to the protective cloth (1c) having air permeability and cushioning ability, the rate of the area of adhesion therebetween may be appropriately in the range of from 3 to 90%, more preferably from 10 to 70%. If the rate of the area of adhesion would be less than 3%, no sufficient intensity of laminating by bonding can be gained. On the other hand, if the rate of the area of adhesion would exceed 90%, then neither air permeability nor vapor permeability can be achieved to a sufficient extent. From the point of view of a balance among adhesion intensity, air permeability and vapor permeability, the rate of the area of adhesion therebetween may appropriately be in the range of from 10% to 70%. This can be said of the partial fusing.
On the other hand, when the vapor-permeable polymer film (1b) is bonded to the sheet (1a) having a great number of air-permeable pores, the rate of the area of adhesion therebetween may be appropriately in the range of from 3 to 99.999%, more preferably from 10 to 99.9%. If the rate of the area of adhesion would be less than 3%, no sufficient intensity of laminating by bonding can be gained. Further, as long as the air-permeable pores portions would not be filled up, the entire surface of the film may be coated with adhesive over the entire area, except for the air-permeable pores portions of the sheet (1a). The area of adhesion in this case may be less at the rate of than 99.999% satisfying the rate of area of the air-permeable pores portions amounting to 0.001% to 40%. The area rate of adhesion in the range of from 10% to 99.9% can be said to be appropriate from the point of view of a balance among adhesion intensity, air permeability and vapor permeability. These can be likewise applied to the fusing.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is a schematic exploded view showing an example of the vapor-permeable and waterproof sheet according to the present invention.
Fig. 2 is a schematic view in section showing a status of execution according to an execution example of the vapor-permeable and waterproof sheet according to the present invention.

EXAMPLES

The present invention will be described in more detail by way of examples, but it should be understood that the present invention is not restricted to those examples in any respect.

Example 1

Fig. 1 shows an example of a vapor-permeable and waterproof sheet 1 according to the present invention. As a sheet 1a having air-permeable pores was used a polytetrafluoroethylene sheet having a film thickness of 4 mm, prepared at a foaming magnification of 30 times, with the air-permeable pores each of 2.6 mm in diameter punched at a distance of 10 mm. As a vapor-permeable polymer film 1b was used a porous polytetrafluoroethylene sheet having a thickness of 50 µm and a maximum pore size of 0.2 micron. As a protective cloth 1c was used a non-woven cloth made of polypropylene long fiber having a thickness of 2.0 mm and a weight of 200 grams per square meter.
For the preparation of the vapor-permeable and waterproof sheet 1, first, the non-woven cloth made of polypropylene long fiber was partially bonded to the porous polytetrafluoroethylene film by melting a surface of the polytetrafluoroethylene non-woven by thermal fusing. Thereafter, the remaining surface of the porous polytetrafluoroethylene film was bonded to a one surface of a polyethylene foam sheet by melting a surface of the polyethylene foam sheet by thermal fusing. The area in which the non-woven cloth of polypropylene long fiber was bonded to the porous polytetrafluoroethylene film to each other was approximately 30% and the area in which the polyethylene foam sheet was bonded to the porous polytetrafluoroethylene film to each other was approximately 95%.
The vapor-permeable and waterproof sheet prepared in this example had a water-resistant pressure (measured in accordance with JIS L 1092) of 4.1 kgf per square meter and a vapor permeability (measured in accordance with JIS L 1099 B-2) of 550 grams per square meter per 24 hours. This indicates that the resulting vapor-permeable and waterproof sheet has a sufficient degree of vapor permeability for the use intended by the present invention although the action of vapor permeability is restricted to the air-permeable pores portion.

Execution Example 1

Fig. 2 indicates an execution example of a vapor-permeable and waterproof sheet according to the present invention. In Fig. 2, reference numeral 3 designates concrete and reference numeral 2 designates a polyethylene foam sheet prepared at a foaming magnification of 30 times, having a thickness of 2 mm and a width of 200 mm, which was used for sealing a bonding portion with the vapor-permeable and waterproof sheet 1. As the sheet 2, although there may be appropriately employed any sheet as long as it is not liquid-permeable, waterproofing and water-resistant, a sheet made of the same material as the sheet 1a is favorable because good bonding strength can be gained with ease.
Reference numeral 5 designates a chloroprene type adhesive which bonded the entire area of the vapor-permeable and waterproof sheet 1 to the polyethylene foam sheet 2. As the adhesive 5, there may be appropriately used adhesive of a synthetic rubber type (chloroprene type, nitrile rubber type or the like), an epoxy type, a thermoplastic type (urethane type or the like) or the like. It is also possible to bond them by fusing, in place of adhesive.
Reference numeral 4 designates a chloroprene type adhesive which was coated on a concrete surface in a lattice form with the vapor-permeable and waterproof sheet 1 partially bonded to the concrete surface 3. As the bonding process for bonding the concrete surface 3 to the vapor-permeable and waterproof sheet 1, there may be mentioned a bonding process in which the entire area of a concrete surface is coated with adhesive having vapor permeability and water resistance in a manner as disclosed in Japanese Patent Publication No. 6-63,323 or a bonding process in which a concrete surface is partially coated with an adhesive of a non-vapor-permeable type such as a synthetic rubber type (chloroprene type, nitrile rubber type or the like) adhesive, an epoxy type adhesive, a thermoplastic type (urethane type or the like) in a spot, linear, lattice or pattern form or the like. For this example, any process may be appropriately used as long as it can sustain a sufficient level of air permeability and vapor permeability for the vapor-permeable and water-proof sheet 1.
With the execution process as described herein-above, a field test was carried out at the roof top of a plant. As a result, it was found in two years after the test that neither separation nor swelling of the vapor-permeable and waterproof sheet 1 were recognized and no waterproofing performance was reduced and it was confirmed that the good waterproofing functions have been sustained.
The vapor-permeable and waterproof sheet according to the present invention can prevent an occurrence of various problems (coming off, swelling, accelerated corrosion of iron reinforcing rods and so on) resulting from vapor, inherent in conventional waterproofing materials, because a protective cloth having air permeability and cushioning ability was laminated on a one surface of a vapor-permeable polymer film by partial bonding and the remaining surface of the film is laminated with a water-resistant sheet having air-permeable pores by partial bonding, thereby allowing the vapor generated from concrete to effectively be discharged from the air-permeable pores portion of the sheet to the outside. Further, as the protective cloth having air permeability and cushioning ability is joined to the concrete surface, it is not broken even if the concrete would be cracked, thereby enabling a prevention of the vapor-permeable and waterproof sheet from breaking. At the same time, even if foreign materials such as small pieces of stones would enter during execution into a gap between the concrete surface and the vapor-permeable and waterproof composite sheet, the vapor-permeable polymer sheet can be prevented from breaking. In addition, as the highly adherent sheet having air-permeable pores is provided on the outermost layer of the vapor-permeable and waterproof composite sheet, the vapor-permeable and waterproof composite sheet can be attached and bonded in a waterproofing way with high reliability and with ease by techniques such as brushing or the like at construction sites.
Furthermore, the vapor-permeable and waterproof sheet for waterproofing concrete readily enables a ready waterproofing attachment and adhesion at sites as a vapor-permeable and waterproof sheet for use between an inner wall and an outer wall of buildings, a vapor-permeable and waterproof sheet for use as general purposes for a building, and so on and it can be extensively applicable as a vapor-permeable and waterproof composite sheet for buildings.

Claims

A vapor-permeable composite sheet for waterproofing concrete characterized by the structure wherein a protective cloth having air permeability and cushioning ability is laminated on a one surface of a polymer film having water repellency and vapor permeability and fixed thereto by partial fusing or bonding and a lightweight and flexible sheet having a number of air-permeable pores is laminated on another surface of said polymer film and fixed thereto by partial fusing or bonding.
A vapor-permeable composite sheet as claimed in claim 1, wherein said polymer film having water repellency and vapor permeability is a porous polymer film of a polyolefinic type, a polyurethane type, a polyester type, a polyether type, a polyvinyl chloride type, a cellulosic type or a fluorocarbon type.
A vapor-permeable composite sheet as claimed in claim 1, wherein said polymer film having water repellency and vapor permeability is a porous polytetrafluoroethylene film.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 3, wherein said protective cloth having air permeability and cushioning ability is a woven or non-woven cloth comprising one or more polymer fiber selected from a polyethylene, a polypropylene, a polyurethane, a nylon, a polyester, a polyvinyl alcohol and a polyvinyl chloride.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 4, wherein said lightweight and flexible sheet is a closed-cell foam sheet comprising a polymer of a mixture type or a composite type containing one or more of a polyethylene, a polypropylene, a polyvinyl acetate or a polyethyl acrylate.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 5, wherein the total area of openings of said air-permeable is 0.1% to 20% of the total area of said sheet.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 6, wherein said polymer film having water repellency and vapor permeability is an oriented polytetrafluoroethylene film.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 7, wherein said polymer film having water repellency and vapor permeability is a porous and oriented polytetrafluoroethylene film having a film thickness of from 3 to 300 µm and a maximum pore size of from 0.01 to 10 µm.
A vapor-permeable composite sheet as claimed in any one of claims 1 to 7, wherein said polymer film having water repellency and vapor permeability is a porous oriented polytetrafluoroethylene film having a film thickness of from 10 to 100 µm and a maximum pore size of from 0.1 to 3 µm.
A vapor-permeable composite sheet as claimed in claim 1 or 6, wherein a non-woven cloth made of polypropylene long fiber is laminated on a one surface of a porous and oriented polytetrafluoroethylene film and fixed thereto by partial bonding or fusing and a polyethylene foam sheet having a number of air-permeable pores is laminated on another surface of said sheet and fixed thereto by partial fusing bonding or fusing.