JP2023066394A - Structure protection sheet and method for manufacturing reinforced structure - Google Patents

Abstract

To provide a structure protection sheet which enables a substantial reduction in construction time, enables protection of a structure having irregularities for a long time, is excellent in strength, and does not develop wrinkles, ruptures, or permanent deformation when attached to the structure.SOLUTION: A structure protection sheet is provided, comprising a polymer cement cured layer provided on the side of a structure, and a resin layer provided on the polymer cement cured layer, has a nonwoven fabric layer at a position contacting the inside of the polymer cement cured layer or the polymer cement cured layer, and has a tensile elastic modulus at elongation of 1% of 100-300 MPa, wherein when the sheet is cut into a test piece with a width of 10 mm and a length of 60 mm, a part of the test piece from one end to 10 mm of the test piece is fixed to a fixed base, and the other end as a free end is suspended from the edge of the fixed base, a distance between the other end as the free end and the fixed base is 30 mm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structure protection sheet and a method for manufacturing a reinforced structure. More specifically, it can significantly reduce the construction period when providing a protective layer on the surface of a structure such as concrete, and can protect even a structure with unevenness for a long period of time. TECHNICAL FIELD The present invention relates to a structure protection sheet capable of preventing tearing and permanent deformation, and a method for manufacturing a reinforced structure using the structure protection sheet.

Civil engineering structures such as road bridges, tunnels, river management facilities such as water gates, sewer pipes, and harbor quays are subject to repair and reinforcement work as they age. Repair work is carried out by recoating the coating material several times after repairing the defective or weak parts. On the other hand, the reinforcement work is carried out by coating the entire portion to be reinforced with a reinforcing coating material multiple times.

Overcoating in such repair work and reinforcement work, for example, is performed on concrete in the order of undercoating, intermediate coating, and topcoating. For example, when applying a total of 5 layers of undercoat, 1st intermediate coat, 2nd intermediate coat, 1st topcoat, and 2nd topcoat, it takes at least 5 days. Moreover, since the painting is done outdoors, it is affected by the weather. Therefore, it is difficult to shorten the construction period, labor costs are high, and the quality of the construction and coating film (film thickness, surface roughness, moisture content, etc.) depends on the external environment (humidity, temperature, etc.) during the coating process. As a result of being affected, it is difficult to become stable.

Painting is done by troweling, spraying, etc., and stable repair and reinforcement by uniform coating largely depends on the skill of the craftsman. Therefore, the quality of the coating film varies depending on the skill of the craftsmen. Furthermore, with the aging of construction workers and the declining population, the number of workers engaged in concrete repair and reinforcement work is decreasing. ing.

As a technique for solving such problems, for example, Patent Document 1 proposes a sheet and a method that are simple, inexpensive, shorten the construction period, and reliably prevent deterioration of concrete. In this technique, a concrete repair sheet comprising an intermediate layer having a resin film and surface layers made of a fabric material laminated on both sides with an adhesive resin is attached to the concrete surface to be repaired with a construction adhesive. and then coating the surface layer of the pasted sheet for repairing concrete on the side opposite to the concrete surface with a coating material.

Improvements have also been made to coating materials. For example, in Patent Document 2, it prevents alkali-aggregate reaction, has excellent conformability to cracks in concrete structures, does not cause blistering of the coating film even when the temperature rises after the coating film is formed, A method for protecting a concrete structure using a coating material capable of preventing concrete from spalling has been proposed. This technique is a method of forming a substrate conditioning material coating film on the surface of a concrete structure and then forming a coating film on the coating film surface. The base conditioning material coating film is formed from a composition containing a cationic (meth)acrylic polymer emulsion and an inorganic hydraulic substance. The coating film formed on the surface of the base conditioning material coating film is a coating film formed from a composition containing an alkyl (meth)acrylate emulsion and an inorganic hydraulic substance, and has an elongation rate of 50 to 2000% at 20°C. and the salt shielding property is 10 ^-2 to 10 ^-4 mg/cm ² . It has a water vapor permeability of 5 g/m·day or more, and a film thickness of 100 to 5000 μm.

JP 2010-144360 A JP-A-2000-16886

Conventional concrete repair sheets such as those disclosed in Patent Document 1 have differences in adhesive strength between the substrate and other layers (e.g., adhesive layer and reinforcing member), differences in elongation of the substrate, adhesive layer, reinforcing member, etc., and adhesion There are problems to be solved, such as the problem of adhesive strength between the agent layer and concrete. Specifically, the base material and the reinforcing member are bonded together with an adhesive layer. Differences in the elongation of members and the like can cause peeling at the layer interface based on the difference in the adhesive strength between the substrate and the adhesive layer and the adhesive strength between the adhesive layer and the reinforcing member.

In addition, the adhesive layer provided on the concrete repair sheet is softened by heating or the like and is bonded to the concrete. It may not work. In addition, after the concrete repair sheet was applied, the concrete sometimes swelled over time. This phenomenon was caused by the presence of the repair sheet, which has low water vapor permeability, and prevented the water vapor inside the concrete from escaping. It is considered to be
Furthermore, when attaching the concrete repair sheet to the concrete, it is necessary to once attach the concrete repair sheet to the structure, align the sheet, and then pull the sheet to prevent wrinkles while maintaining the desired shape and position of the sheet. There is
However, the conventional concrete repair sheet has a problem that the elongation against the applied stress is very large and the sheet is torn or permanently deformed.

In addition, the method of forming a coating film by coating on site, as described in the background art section above, takes one day for each coating layer, and from the undercoat to the topcoat layer, for example, a six-layer coating film. It takes as long as 6 days to form , and there are problems that the film thickness varies and the quality and characteristics such as surface roughness and water content are difficult to stabilize.

In addition, the repair target of the concrete repair sheet is usually large concrete members such as road bridges, tunnels, water gates and other river management facilities, sewer pipes, harbor quays and other civil engineering structures, so the concrete repair sheet itself is sufficient. strength (tensile strength, bending strength, hardness, surface strength, punching strength, toughness, etc.; the same applies hereinafter) is required, but conventional concrete repair sheets are considered to have sufficient strength. is difficult to say.

On the other hand, a method of laminating a mesh or the like on a conventional concrete repair sheet to give sufficient strength has been studied, but the concrete repair sheet is too rigid and difficult to bend, resulting in poor conformability to the surface shape of the repair target. There was a problem. A method of thinning the mesh in consideration of the surface followability is also conceivable, but there is a problem that when the mesh is thinned, it deforms when attached to a structure or the like, resulting in wrinkles and poor appearance.

The present invention has been made to solve the above-mentioned problems, and its object is to significantly reduce the construction period when providing a protective layer on the surface of a structure such as concrete, and to prevent the structure from having unevenness. A structure protection sheet that can protect a structure for a long period of time even if it has a high strength, is excellent in strength, and does not cause wrinkling, tearing, or permanent deformation when attached to a structure, and its structure protection. An object of the present invention is to provide a method for manufacturing a reinforced structure using a sheet.

The inventors of the present invention have found that even a structure having unevenness can be protected for a long period of time without creating gaps or wrinkles, without relying on the construction method of forming a layer on the surface of concrete by coating means. A structure protection sheet was studied. As a result, it was found that the concrete protection sheet should be given performance according to the characteristics of the concrete. In addition to waterproofing, salt blocking, neutralization prevention, and water vapor permeability that allows the water in concrete to be discharged as water vapor, the concrete protection sheet itself has a moderate tensile modulus and bending elasticity. and completed the present invention. This technical idea can also be applied as a structure protection sheet to structures other than those for concrete.

(1) A structure protection sheet according to the present invention is a structure protection sheet comprising a polymer cement hardened layer provided on the structure side, and a resin layer provided on the polymer cement hardened layer, wherein the polymer A test piece having a nonwoven fabric layer in the cement hardened layer or at a position in contact with the polymer cement hardened layer, having a tensile modulus of 100 to 300 MPa at an elongation of 1%, and having a width of 10 mm and a length of 60 mm is cut into the above test piece. 10 mm from one end of is fixed to the fixed base, and the other end is made to hang from the edge of the fixed base as a free end, the distance from the other free end to the fixed base is It is characterized by being 30 mm or less.

According to this invention, the hardened polymer cement layer provided on the structure side has excellent adhesion to the structure, etc., and has moderate tensile elasticity and moderate bending elasticity. Even if there is, it can be protected for a long time, it has excellent strength, and when it is attached to a structure, it prevents wrinkles and does not tear or permanently deform.
In addition, since the structure protection sheet can be mass-produced by coating and drying processes on the factory production line, it is possible to reduce costs, significantly reduce the work period on site, and achieve long-term protection of structures.

(2) In the present invention, the nonwoven fabric layer has a structure in which fibers selected from inorganic fibers, organic fibers, and inorganic and organic mixed fibers are formed into a sheet without weaving. A structure protection sheet is preferred.

According to this invention, the structure protection sheet according to the present invention can achieve an appropriate tensile elastic modulus and bending elasticity.

(3) In the present invention, the polymer cement-hardened layer is a layer containing a cement component and a resin, and contains 10% by weight or more and 40% by weight or less of the resin. It is preferably the structure protection sheet described. More preferably, the resin content is 20% by weight or more and 30% by weight or less.

According to the present invention, by controlling the ratio of the cement component and the resin component, it becomes easier to form the polymer cement hardened layer, and the polymer cement hardened layer tends to be a layer with excellent conformability and good compatibility. It tends to improve the adhesiveness of itself. Furthermore, the cement component contained in the polymer-cement-hardened layer on the structure side acts to enhance adhesion to structures such as concrete.

(4) A method for manufacturing a reinforced structure according to the present invention is a method for manufacturing a reinforced structure using the structure protection sheet according to the present invention described in (1), (2) or (3) above. The method is characterized in that the structure protection sheet is laminated after the adhesive is applied onto the structure.
(5) A method for manufacturing a reinforced structure according to the present invention is a method for manufacturing a reinforced structure using the structure protection sheet according to the present invention described in (1), (2) or (3) above. In the method, an adhesive is applied to the surface of the structure protection sheet where the polymer cement hardening layer is exposed to form an adhesive layer, and the structure is mounted so that the adhesive layer is in contact with the surface of the structure. It is also characterized by laminating an object protection sheet.

According to the present invention, since the structure protection sheet is composed only of a layer that does not contain a base material or a reinforcing member, it can be easily attached to the surface of a structure having irregularities. As a result, even an unskilled worker can stably apply a structure protection sheet with excellent strength to the surface of a structure, significantly reducing the construction period and protecting the structure over a long period of time. Furthermore, it is possible to prevent the occurrence of wrinkles, tearing, and permanent deformation during the pulling after positioning.

(6) The present invention is preferably the method for producing a reinforced structure according to (4), wherein an undercoat layer is provided between the structure and the adhesive.

According to this invention, the undercoat layer provided between the structure and the adhesive acts to enhance mutual adhesion, so that the structure protection sheet can stably protect the structure for a long period of time. .

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a structure protection sheet capable of protecting a structure such as concrete for a long period of time and preventing wrinkles, tearing, and permanent deformation when applied to a structure having unevenness, and a structure protection sheet thereof. A method for manufacturing a reinforced structure using the structure protection sheet can be provided. In particular, the structure protection sheet is given performance according to the characteristics of the structure, so that it can follow the cracks and expansion that occur in the structure, and it prevents deterioration factors such as water and chloride ions from penetrating into the structure. In addition, it is possible to provide a structure protection sheet that achieves permeability that allows the discharge of moisture and deterioration factors in the structure, and that has improved strength and bending elasticity. Furthermore, it has the advantage of being able to improve the stability and uniformity of quality compared to layers that have been formed by hand coating.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional block diagram which shows an example of the structure protection sheet which concerns on this invention. It is explanatory drawing of the construction method of a structure protection sheet. It is explanatory drawing which shows the example which applied the structure protection sheet to the cast-in-place construction method. FIG. 4 is an explanatory diagram of a method for measuring the flexural elasticity of the structure protection sheet according to the present invention;

Hereinafter, a structure protection sheet according to the present invention and a construction method using the sheet will be described with reference to the drawings. The present invention can be modified in various ways as long as it has the technical features, and is not limited to the following description and drawings.

[Structure protection sheet]
As shown in FIG. 1 or FIG. 2C, the structure protection sheet 1 according to the present invention comprises a hardened polymer cement layer 3 provided on the side of a structure 21, and a hardened polymer cement layer 3 provided on the hardened polymer cement layer 3. layer 2; Both the polymer cement hardened layer 3 and the resin layer 2 may be formed as a single layer or as a laminate. Another layer may be provided between the hardened polymer cement layer 3 and the resin layer 2 depending on the required performance.

The structure protection sheet 1 according to the present invention has a tensile elastic modulus of 100 to 300 MPa at an elongation of 1%. If the tensile modulus of elasticity is less than 100 MPa, when the structure protection sheet 1 according to the present invention is attached to the structure 21 and pulled for the purpose of smoothing out wrinkles after positioning, the sheet is torn or permanently deformed. If the tensile modulus of elasticity exceeds 300 MPa, the structure protection sheet 1 according to the present invention is too rigid, and when the structure protection sheet 1 according to the present invention is attached to the structure 21, it cannot be sufficiently pulled after positioning. A preferable lower limit of the tensile elastic modulus of the structure protection sheet 1 according to the present invention is 100 MPa, and a preferable upper limit thereof is 200 MPa.
If the tensile elongation is less than 1%, an error is likely to occur due to slippage between the sample and the chuck holding the sample. In addition, although the tensile elongation may be arbitrary between 1% and 5%, there are samples where the yield point occurs when it exceeds 5%. was used.
The tensile modulus can be measured, for example, using a known tensile tester, and a method of calculating by the least squares method using each stress at two points of tensile elongation 0% and 1% is used. (Regression method).

Further, the structure protection sheet 1 according to the present invention is cut into a test piece 40 having a width of 10 mm and a length of 60 mm as shown in FIG. 41 and the other end as a free end to hang down from the edge of the fixing base 41, the distance from the other free end to the fixing base 41 is 30 mm or less.
Specifically, the test piece 40 is fixed so as to protrude from the edge of the fixing table 41 by 50 mm, and when the protruding end is set as a free end, the protruding portion hangs down due to the weight of the test piece 40 itself. At this time, if the flexural elasticity of the test piece 40 is small, the test piece 40 tends to bend as shown in FIG. When the flexural elasticity of the test piece 40 is large, the test piece 40 is difficult to bend as shown in FIG.
In the structure protection sheet according to the present invention, the distance D is 30 mm or less. When the distance D exceeds 30 mm, the bending workability at the corners of the unevenness is deteriorated, and a gap is generated when the tape is attached to the surface of the structure having the unevenness.

Such tensile elastic modulus and flexural elasticity can be obtained by appropriately selecting materials for the layers constituting the structure protection sheet 1 according to the present invention. achievable.

Such a structure protection sheet 1 according to the present invention can be elastically deformed when pulled after positioning when the structure protection sheet 1 according to the present invention is attached to a structure 21, and can prevent tearing and permanent deformation due to pulling. .

The structure protection sheet 1 according to the present invention preferably has a thickness distribution within ±100 μm. Since the structure protection sheet 1 has a thickness distribution within the above range, even an unskilled worker can stably form a layer with small thickness variations on the surface of the structure 21 . Further, by controlling the thickness distribution within the above range, it becomes easier to uniformly reinforce the structure.
The hardened polymer cement layer 3 provided on the side of the structure 21 has excellent adhesion to the structure 21, and since it has the nonwoven fabric layer 5, it can also provide the property of ensuring strength. Moreover, the resin layer 2 provided on the polymer cement hardened layer 3 can impart properties such as waterproofness, salt barrier properties, and neutralization prevention properties.
In addition, since the structure protection sheet 1 can be mass-produced by the coating process and the drying process on the production line of the factory, it is possible to reduce the cost, significantly reduce the work period at the site, and achieve long-term protection of the structure. As a result, it is possible to greatly reduce the time required for attaching the film to the surface of the structure 21 and to protect the structure 21 for a long period of time.

Specific examples of each component will be described in detail below.

(Structure)
The structure 21 is a mating member to which the structure protection sheet 1 according to the present invention is applied.
As the structure 21, a structure made of concrete can be mentioned.
The concrete is generally obtained by placing and curing a cement composition containing at least a cementitious inorganic substance, an aggregate, an admixture and water. Such concrete is widely used as civil engineering structures such as road bridges, tunnels, water gates and other river management facilities, sewer pipes, harbor quays and the like. In the present invention, by applying the structure protection sheet 1 to the structure 21 made of concrete, it is possible to follow the cracks and expansion that occur in the concrete, and prevent deterioration factors such as water and chloride ions from penetrating into the concrete. There is a particular advantage that water in concrete can be discharged as steam.

The structure 21 may have unevenness formed on its surface, and the structure protection sheet 1 according to the present invention satisfies the tensile elastic modulus and bending elasticity described above. It can be protected for a long time, has excellent strength, and does not wrinkle, tear, or permanently deform when attached to a structure.

(polymer cement hardening layer)
The polymer cement hardening layer 3 is a layer arranged on the structure side, as shown in FIG. 2(C). This polymer cement hardening layer 3 may be a single layer or a laminate. ), can be arbitrarily set in consideration of the production line of the factory, production cost, etc. For example, if the production line is short and a single layer does not have a predetermined thickness, two or more layers can be overcoated. For example, when two layers are overcoated, the second layer is formed after drying the first layer.
The hardened polymer cement layer 3 may also have a structure in which layers having different properties are laminated. For example, by forming a layer with a higher resin component ratio on the resin layer 2 side, the layer with a high resin component adheres to the resin layer, and the layer with a high cement component adheres to the concrete structure. It has excellent properties.

The hardened polymer cement layer 3 is obtained by coating a resin containing a cement component (resin component) in the form of a coating.
Examples of the cement component include various cements, limestones containing calcium oxide, and clays containing silicon dioxide. Among them, cement is preferable, and examples thereof include portland cement, alumina cement, high-early strength cement, fly ash cement, and the like. Which cement is selected is selected according to the properties that the hardened polymer cement layer 3 should have, for example, considering the degree of conformability to the structure 21 made of concrete. Portland cement defined in JIS R5210 is particularly preferred.

Examples of the resin component include acrylic resin, acrylic urethane resin, acrylic silicone resin, fluororesin, flexible epoxy resin, polybutadiene rubber, acrylic resin exhibiting rubber properties (e.g., synthetic rubber containing acrylic acid ester as a main component), etc. can be mentioned. Such a resin component is preferably the same as the resin component constituting the resin layer 2 described later, from the viewpoint of enhancing the adhesion between the polymer cement hardened layer 3 and the resin layer 2 .
Moreover, any of a thermoplastic resin, a thermosetting resin, and a photocurable resin may be used as the resin component. The term "cured" in the polymer cement cured layer 3 does not mean that the resin component is limited to a resin that cures and polymerizes, such as a thermosetting resin or a photocurable resin. It is used in the sense that it is sufficient to use a material that hardens to a certain degree.

The content of the resin component is appropriately adjusted depending on the material to be used, etc., but is preferably 10% by weight or more and 40% by weight or less with respect to the total amount of the cement component and the resin component. If it is less than 10% by weight, the adhesiveness to the resin layer 2 tends to decrease and it becomes difficult to maintain the hardened polymer cement layer 3 as a layer. 21 may be insufficient. From the above viewpoint, the content of the resin component is more preferably 15% by weight or more and 35% by weight or less, and more preferably 20% by weight or more and 30% by weight or less.

The paint for forming the hardened polymer cement layer 3 is a coating liquid obtained by mixing a cement component and a resin component with a solvent. The resin component is preferably an emulsion. For example, an acrylic emulsion is polymer fine particles obtained by emulsion polymerization of a monomer such as an acrylic ester using an emulsifier. An acrylic polymer emulsion obtained by polymerizing a mixture in water containing a surfactant is preferably used.
The content of the acrylic acid ester and the like constituting the acrylic emulsion is not particularly limited, but is selected within the range of 20 to 100% by mass. Further, the amount of the surfactant is also blended according to need, and the amount is not particularly limited, but the surfactant is blended to the extent that it forms an emulsion.

The hardened polymer cement layer 3 is formed by applying the coating solution onto a release sheet and then removing the solvent (preferably water) by drying. For example, a mixed composition of a cement component and an acrylic emulsion is used as a coating liquid to form the hardened polymer cement layer 3 . Although the resin layer 2 may be formed on the release sheet after forming the polymer cement hardened layer 3, the polymer cement hardened layer 3 is formed after the resin layer 2 is formed on the release sheet. may
Specifically, for example, a process paper as a release sheet is coated with a resin layer, and after drying, a coating solution for polymer cement is applied, and a nonwoven fabric layer is laminated in a wet state before drying, followed by drying. .
After that, a coating liquid for polymer cement is further applied to the surface to which the nonwoven fabric layer is attached, and dried to obtain the structure protection sheet 1 in which the nonwoven fabric layer is present in the polymer cement hardened layer 3 according to the present invention. can be done.
In addition, the process paper as a release sheet is coated with a resin layer, and after drying, a coating liquid for polymer cement is applied, and the nonwoven fabric layer is bonded together in a wet state before drying, without the step of drying. A coating liquid for polymer cement is further applied to the surface to which the nonwoven fabric layer is attached, and then the whole is dried to obtain the structure protection sheet 1 according to the present invention in which the nonwoven fabric layer is present on the polymer cement hardened layer. It is also possible to obtain

The thickness of the hardened polymer cement layer 3 is not particularly limited, and the type of use of the structure 21 (road bridge, tunnel, river facilities such as water gates, civil engineering structures such as sewage pipes, harbor quays, etc.), degree of aging, shape, etc. Arbitrarily set by Specifically, the thickness of the hardened polymer cement layer 3 can be, for example, in the range of 0.5 mm to 1.5 mm. As an example, when the thickness is 1 mm, the thickness variation is preferably within ±100 μm. Such a precise thickness cannot be achieved by on-site coating, but can be achieved by stably coating on a factory production line. Even if the thickness is greater than 1 mm, the thickness variation can be kept within ±100 μm. Moreover, when the thickness is less than 1 mm, the thickness variation can be further reduced.

Due to the presence of the cement component, this hardened polymer cement layer 3 is more easily permeable to water vapor than the resin layer 2 which will be described later. The water vapor transmission rate at this time is, for example, about 20 to 60 g/m ² .day. Furthermore, the cement component has good compatibility with, for example, the cement component that constitutes concrete, and can be made to have excellent adhesion to the concrete surface. Also, as shown in FIG. 2, when the undercoat layer 22 and the adhesive 23 are provided in order on the surface of the structure 21, the polymer cement hardened layer 3 containing the cement component adheres well to the adhesive 23. Glue. In addition, since the hardened polymer cement layer 3 has extensibility, it can follow changes in the concrete even if the structure 21 cracks or expands.

(Nonwoven fabric layer)
The nonwoven fabric layer 5 may exist in the polymer cement hardening layer 3 as shown in FIG. on the opposite side). Above all, it is preferable that the nonwoven fabric layer 5 is embedded inside the hardened polymer cement layer 3 . By embedding the nonwoven fabric layer 5 inside the polymer cement hardening layer 3, the contact area between the nonwoven fabric layer 5 and the polymer cement hardening layer 3 is increased, and the adhesion strength between the two is easily improved, and the polymer cement is formed. The strength of the hardened layer 3 as a whole can also be easily ensured.
On the other hand, the nonwoven fabric layer 5 is provided in contact with the hardened polymer cement layer 3 because the bending elasticity and tensile elastic modulus of the structure protection sheet 1 according to the present invention can be easily adjusted within the ranges described above. preferable.

In the present invention, it is preferable that the nonwoven fabric layer 5 is impregnated with a material (for example, a cement component or a resin component) that constitutes the cement-hardened polymer layer 3 .
The state in which the nonwoven fabric layer 5 is impregnated with the material constituting the hardened polymer cement layer 3 is a state in which the material constituting the hardened polymer cement layer 3 is filled between the materials such as fibers constituting the nonwoven fabric layer 5. In other words, such an impregnated state makes it easier to make the bonding strength between the nonwoven fabric layer 5 and the polymer cement hardened layer 3 extremely excellent. Further, the interaction between the nonwoven fabric layer 5 and the material of the polymer cement hardening layer 3 tends to become stronger, and the strength of the structure protection sheet 1 tends to be improved.

The nonwoven fabric forming the nonwoven fabric layer 5 is not particularly limited as long as it is a nonwoven fabric formed into a sheet without weaving fibers.
In addition, the fibers constituting the nonwoven fabric are preferably inorganic materials, organic materials, and inorganic and organic mixed materials, and are particularly limited as long as they are nonwoven fabrics formed into a sheet without weaving fibers. not a thing
Among them, natural fibers, chemical fibers, regenerated fibers, and the like can be used more preferably as the material of the fibers constituting the nonwoven fabric because of their lightness and economic efficiency of procurement.
Examples of the natural fibers include cotton, hemp, and kenaf.
Examples of the chemical fibers include fibers made of polyolefin resins such as polypropylene and polyethylene, polyester resins, polyacrylic resins, polyamide resins such as nylon, vinylon fibers, rayon fibers, cellulose fibers, and copolymers of these resins. and synthetic fibers made of synthetic fibers, modified materials, and combinations thereof.
Examples of the regenerated fibers include rayon and cupra.
Among these, polyester fiber and rayon are preferable because they are excellent in water resistance, heat resistance, dimensional stability, weather resistance, and the like.
In the nonwoven fabric layer 5, additives such as particles, antistatic agents, and ultraviolet stabilizers may be added to the materials constituting the fibers described above. Alternatively, biological materials may be used.

The nonwoven fabric layer 5 generally has a short fiber nonwoven fabric, a long fiber nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, a thermal bonded (air-through) nonwoven fabric, Nonwoven fabrics are classified into needle-punched nonwoven fabrics, point-bonded nonwoven fabrics, laminated nonwoven fabrics (such as SMS nonwoven fabrics and SMMS nonwoven fabrics in which a meltblown layer is sandwiched between spunbond layers), and any of these nonwoven fabrics can be used.

The basis weight of ^the nonwoven fabric is not particularly limited as long as it ^is within a range that can satisfy the above- ^described tensile elastic modulus and flexural elasticity. 50 g/m ² or less is more preferable. If the basis weight of the nonwoven fabric is less than the above range, the nonwoven fabric may become thin and may not satisfy the above-mentioned range of tensile modulus. Conversely, if the basis weight of the nonwoven fabric exceeds the above range, the above bending elasticity is satisfied. Otherwise, the air permeability of the structure protection sheet 1 according to the present invention may deteriorate.

The nonwoven fabric layer 5 may have a size that covers the entire surface of the polymer cement-hardened layer 3 when viewed from the top side of the polymer cement-hardened layer 3 , or may be smaller than the polymer cement-hardened layer 3 . That is, the area of the nonwoven fabric layer 5 when viewed in plan may be the same as or smaller than the area of the hardened polymer cement layer 3 when viewed in plan. It is preferably 60% or more, more preferably 90% or more, of the planar view area of the cement-hardened layer 3 . If it is less than 60%, the strength of the structure protection sheet according to the present invention may be insufficient, and the strength may vary. In addition, the planar view area of the said nonwoven fabric layer 5 grade|etc., can be measured by a well-known method.

Moreover, the nonwoven fabric layer 5 may be a uniform layer, and may be, for example, a layer having a checkerboard pattern, a zigzag pattern, a striped pattern, an island pattern, or an irregular crimped portion. By providing the crimped portion, it is possible to prevent the fibers of the nonwoven fabric layer 5 from unraveling during the lamination process. Further, it is possible to adjust the difference in bending elasticity between the direction parallel to the lamination process and the direction perpendicular to the lamination process, which is preferable.
A resin adhesive may be used for crimping or adhering the nonwoven fabric layer 5 . When fixed with an adhesive, it is possible to prevent the assembly of fibers from unraveling during the lamination process.

(resin layer)
The resin layer 2 is a layer arranged on the side opposite to the structure 21 and appearing on the surface, as shown in FIG. 2(C). The resin layer 2 may be, for example, a single layer as shown in FIG. 1(A), or may be a laminate consisting of at least two layers as shown in FIG. 1(B). Whether to use a single layer or multiple layers takes into account the overall thickness, the functions to be imparted (waterproofness, salt barrier, neutralization prevention, water vapor permeability, etc.), the length of the factory production line, the production cost, etc. For example, if the production line is short and a single layer does not have a predetermined thickness, two or more layers can be overcoated. In the case of overcoating, the second layer is applied after drying the first layer. The second layer is then dried.

The resin layer 2 is coated with a paint that has flexibility, can follow cracks and cracks that occur in concrete, and can form a resin layer that is excellent in waterproofness, salt shielding, neutralization prevention, and water vapor permeability. obtained by Examples of the resin constituting the resin layer 2 include acrylic resins exhibiting rubber characteristics (for example, synthetic rubber containing acrylic acid ester as a main component), acrylic urethane resins, acrylic silicone resins, fluorine resins, flexible epoxy resins, polybutadiene rubbers, and the like. can be mentioned. This resin material is preferably the same as the resin component constituting the polymer cement hardening layer 3 described above. In particular, it is preferably a resin containing an elastic film-forming component such as rubber.

Among these, the acrylic resin exhibiting rubber properties is preferably composed of an aqueous emulsion of an acrylic rubber copolymer in terms of excellent safety and coatability. Incidentally, the proportion of the acrylic rubber copolymer in the emulsion is, for example, 30 to 70% by mass. An acrylic rubber copolymer emulsion is obtained, for example, by emulsion polymerization of monomers in the presence of a surfactant. Any of anionic, nonionic and cationic surfactants can be used.

The paint for forming the resin layer 2 is prepared by preparing a mixed coating liquid of a resin composition and a solvent, applying the coating liquid on a release sheet, and then removing the solvent by drying. Form layer 2; The solvent may be water, an aqueous solvent, or an organic solvent such as xylene/mineral spirit. In Examples described later, a water-based solvent is used, and the resin layer 2 is made of an acrylic rubber composition. The order of the layers formed on the release sheet is not limited. may be in that order. However, it is preferable to form the resin layer 2 on the release sheet and then form the hardened polymer cement layer 3, as shown in Examples described later.

The thickness of the resin layer 2 is arbitrarily set according to the type of use of the structure 21 (road bridge, tunnel, river management facility such as a water gate, civil engineering structure such as a sewage pipe, port quay, etc.), degree of aging, shape, and the like. be. As an example, it is preferable that the thickness be within the range of 50 to 150 μm, and that the thickness variation be within ±50 μm. Thickness with such precision cannot be achieved by coating on site, and can be stably achieved on the production line of the factory.

This resin layer 2 has high waterproof properties, salt-shielding properties, and neutralization-preventing properties, but is preferably permeable to water vapor. At this time, it is desirable that the water vapor transmission rate is, for example, about 10 to 50 g/m ² .day. By doing so, the structure protection sheet 1 can be endowed with high waterproof properties, salt barrier properties, neutralization prevention properties, and predetermined water vapor permeability. Further, by being composed of the same kind of resin component as the polymer cement hardening layer 3, the compatibility with the polymer cement hardening layer 3 is good and the adhesion can be excellent. The water vapor permeability was measured according to JIS Z0208 "Test method for moisture permeability of moisture-proof packaging materials".

Moreover, the resin layer 2 may contain a pigment from the viewpoint of increasing the color variations of the structure protection sheet 1 according to the present invention.
Moreover, the resin layer 2 may contain an inorganic substance. By containing an inorganic substance, the resin layer 2 can be imparted with scratch resistance. The inorganic material is not particularly limited, and examples thereof include conventionally known materials such as metal oxide particles such as silica, alumina, and titania.
Furthermore, the resin layer 2 may contain a known antifouling agent. Since the structure protection sheet according to the present invention is usually used for repairing concrete structures installed outdoors, the resin layer 2 is often contaminated. It is possible to suitably prevent the structure protection sheet from being contaminated. The antifouling agent is not particularly limited and includes conventionally known materials.
Moreover, the resin layer 2 may contain additives capable of imparting various functions. Examples of such additives include cellulose nanofibers and the like.

(Other configurations)
The manufactured structure protection sheet 1 may have a release sheet on one side of the polymer cement hardening layer 3 and the resin layer 2 . For example, the release sheet can protect the surface of the structure protection sheet 1 when it is sent to the construction site, and at the construction site, it is applied on the target structure 21 (or via the undercoat layer 22 or the adhesive 23). 3) Adhering the structure protection sheet 1 to which the release sheet is attached and then easily peeling off the release sheet greatly improves workability at the construction site. The release sheet is preferably process paper used in the production process of the structure protection sheet 1 .

The process paper used as the release sheet is not particularly limited in terms of its material, etc., as long as it is conventionally known and used in the manufacturing process. For example, laminated paper having an olefin resin layer such as polypropylene or polyethylene or a silicon-containing layer, like known process paper, can be preferably used. The thickness is not particularly limited, but it can be any thickness, for example, about 50 to 500 μm, as long as the thickness does not impede handling in terms of manufacturing and construction.

The structure protection sheet 1 described above can protect the structure 21 such as concrete for a long period of time. In particular, the structure protection sheet 1 is given performance according to the characteristics of the structure 21 to follow cracks and expansions that occur in the structure 21, and permeation of deterioration factors such as water and chloride ions into the structure 21. It is possible to prevent the occurrence of wrinkles and tearing because it is possible to provide permeability that can discharge moisture and deterioration factors in the structure, and it can be suitably pulled when it is attached to a structure having unevenness. Prevents permanent deformation. Since such a structure protection sheet 1 can be manufactured in a factory, it is possible to mass-produce high-quality sheets with stable characteristics. As a result, it can be constructed without relying on the skills of craftsmen, shortening the construction period and reducing labor costs.

[Method for manufacturing reinforced structure using structure protection sheet]
The method for manufacturing a reinforced structure using the structure protection sheet according to the present invention is a construction method using the structure protection sheet 1 according to the present invention, as shown in FIG. It is characterized in that the structure protection sheet 1 is pasted after the adhesive 23 is applied thereon. This construction method can easily bond the structure protection sheet 1 to the surface of the structure 21 . As a result, even an unskilled worker can provide the structure protection sheet 1 composed of a layer with a small thickness variation on the structure 21, thereby significantly reducing the construction period and extending the structure 21. can be protected over

FIG. 2 is an explanatory view of a construction method of the structure protection sheet 1 (manufacturing method of a reinforced structure). Construction forms the undercoat layer 22 on the surface of the structure 21, as shown in FIG. 2(A). The undercoat layer 22 can be formed by coating the structure 21 with a coating liquid obtained by mixing a resin such as an epoxy resin and a solvent, and then volatilizing and drying the solvent in the coating liquid. Examples of the solvent at this time include water and the like similar to those described above. Although the thickness of the undercoat layer 22 is not particularly limited, it can be in the range of 100 to 150 μm, for example. Since the undercoat layer 22 provided between the structure 21 and the adhesive 23 acts to enhance mutual adhesion, the structure protection sheet 1 can stably protect the structure 21 for a long period of time. If the structure 21 is cracked or damaged, it is preferable to provide the undercoat layer 22 after repairing it. Also, the repair is not particularly limited, but usually cement mortar, epoxy resin, or the like is used.

After forming the undercoat layer 22, an adhesive 23 is applied as shown in FIG. 2(B). Without drying the applied adhesive 23, the structure protection sheet 1 is adhered thereon as shown in FIG. 2(C). Examples of the adhesive 23 include urethane-based adhesives, epoxy-based adhesives, and adhesives using acrylic resins exhibiting rubber characteristics (for example, synthetic rubber containing acrylic acid ester as a main component). Among them, the adhesive 23 composed of the same resin component as the resin component constituting the polymer cement hardened layer 3 of the structure protection sheet 1 is more preferable because the adhesive strength with the polymer cement hardened layer 3 is increased. The thickness of the adhesive 23 is not particularly limited. The adhesive 23 is usually applied to concrete by means of brushing or spraying, and then naturally dried and hardened over time.

A method for manufacturing a reinforced structure using the structure protection sheet according to the present invention is a construction method using the structure protection sheet according to the present invention, wherein the polymer cement hardened layer of the structure protection sheet is It is also characterized in that an adhesive is applied to the exposed surface to form an adhesive layer, and the structure protection sheet is attached so that the adhesive layer is in contact with the surface of the structure. This construction method can easily bond the structure protection sheet to the surface of the structure. As a result, even an unskilled worker can provide a structure protection sheet composed of layers with small variations in thickness on a structure, thereby significantly reducing the construction period and protecting the structure over a long period of time. be able to.

The adhesive to be applied to the surface of the structure protection sheet where the polymer cement hardened layer is exposed is not particularly limited, and a known adhesive that can be applied to the surface of a structure such as concrete and that can adhere a resin film is used. For example, an acrylic pressure-sensitive adhesive or the like is preferably used.
The coating amount of the adhesive is preferably, for example, 20 g/m ² or more and 100 g/m ² or less, and the adhesive strength of the adhesive layer to be formed is preferably 30 N/25 mm or more and 60 N/25 mm or less. As described above, the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive, and the coating amount of the pressure-sensitive adhesive and the adhesive strength of the pressure-sensitive adhesive layer are within the above ranges. can be reliably fixed to the wall surface of the structure.
In addition, since the amount of the adhesive applied is within the above range, even if there are minute dents on the wall surface of a concrete structure, etc., the adhesive layer can be embedded in the dents, and the concrete structure of the structure protection sheet can be obtained. Adhesion to structures such as objects can be enhanced.

FIG. 3 is an explanatory diagram showing an example in which the structure protection sheet 1 is applied to the cast-in-place construction method. The cast-in-place method is a construction method in which a formwork 24 is formed at a work site, a concrete composition 21' is poured into the formwork 24, and left to harden to obtain a structure 21 made of concrete. In this cast-in-place method, after forming the structure 21 made of hardened concrete, the structure protection sheet 1 is attached to the surface of the structure 21 , thereby making the structure 21 resistant to deterioration. In bonding, the undercoat layer 22 is applied to the surface of the structure 21 made of concrete and dried, the adhesive 23 is applied thereon, and then the structure protection sheet 1 is bonded. Thereafter, the structure protection sheet 1 is adhered by drying and curing the adhesive 23 by leaving it to stand naturally.

On the other hand, for the structure 21 already cracked or the like, after repairing the damaged portion, the structure protection sheet 1 is attached by the same construction method as described above. In this way, the life of the structure 21 made of concrete can be extended.

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples.

(Example 1)
A release sheet made of PP-laminated paper and having a thickness of 130 μm was used. A resin layer was formed on this release sheet by the following method.
First, a water-soluble acrylic emulsion containing 60 parts by mass of acrylic silicone resin, 25 parts by mass of titanium dioxide, 10 parts by mass of ferric oxide, and 5 parts by mass of carbon black was prepared. After the water-soluble acrylic emulsion was applied onto the release sheet, it was cured by heat treatment to form a resin layer. The thickness of the resin layer after drying was set to 0.1 mm.
Next, a polymer cement hardening layer was formed on the resin layer.
Specifically, a water-based acrylic emulsion containing 45 parts by mass of a cement mixture was prepared as a composition for forming a polymer cement layer. Here, the cement mixture contains at least 70 ± 5 parts by mass of Portland cement, 10 ± 5 parts by mass of silicon dioxide, 2 ± 1 parts by mass of aluminum oxide, and 1 to 2 parts by mass of titanium oxide. It contains at least 53±2 parts by mass of an acrylic polymer obtained by emulsion polymerization using an acid ester monomer as an emulsifier and 43±2 parts by mass of water. The polymer cement hardened layer obtained by coating and drying the polymer cement layer-forming composition in which these are mixed is a composite layer containing 50% by mass of Portland cement in the acrylic resin.
The above composition for forming a polymer cement hardened layer was applied onto the resin layer so that the thickness after drying was 0.3 mm, and before drying, a PET spandex with a basis weight of 35 g / m ² was applied. A nonwoven fabric layer was provided. The nonwoven fabric was dried in a state in which the nonwoven fabric was submerged in the hardened layer 3 of polymer cement.
Thus, a structure protection sheet with a total thickness of 0.6 mm was produced. In addition, this structure protection sheet was continuously produced in a factory controlled at about 25° C., and was wound into a roll while including a release sheet.

[Measurement of tensile modulus]
The tensile elastic modulus of the structure protection sheet 1 obtained in Example 1 was measured using a tensile tester (AGX-V, manufactured by Shimadzu Corporation).
The tensile modulus of Example 1 was 131 MPa.

[Measurement of bending elasticity]
A test piece 40 (width 10 mm, length 60 mm) shown in FIG. , the other end of which hangs down from the edge of the fixing base 41 as a free end, and the distance D from the other free end to the fixing base 41 is 22 mm.

[Processability]
The structure protection sheet obtained in Example 1 was cut out to a length of 300 mm and a width of 300 mm, and an adhesive (SP-1090NT manufactured by DIC) was applied to the surface where the hardened polymer cement layer was exposed using an applicator. and dried in a hot air oven at 80° C. for 10 minutes to form a pressure-sensitive adhesive layer having a thickness of 100 μm to prepare a sample.
The obtained sample was attached to a concrete test piece having a step of 5 mm so that the pressure-sensitive adhesive layer was in contact with the concrete test piece at a position of 150 mm in the longitudinal direction of the sample so as to be in contact with the concrete step. At that time, the lower side of the step was attached first, and the sample was pulled upward by hand and pushed into the step.
When the sample made of the structure protection sheet was pulled by hand, it was evaluated as "O" when it did not stretch and deformed, and as "X" when it stretched and its flatness was deformed.
In addition, the part pushed into the step was observed after 24 hours, and the sample made of the structure protection sheet was visually observed at the step. was evaluated as "x".
[Comprehensive judgment]
In the evaluation of processing suitability, when both were ◯, it was comprehensively judged as “◯”, and when either one was ×, it was comprehensively judged as “×”.

The structure protection sheet 1 according to Example 1 is excellent in tensile elastic modulus and flexural elasticity and maintains appropriate elasticity when attached to a structure, which is convenient for construction work, and causes wrinkles, tears, and permanent deformation. It was nothing.

(Examples 2 and 3, Comparative Examples 1 to 5)
A structure protection sheet was prepared in the same manner as in Example 1 except that the thickness of the resin layer and the type and basis weight of the nonwoven fabric layer were changed as shown in Table 1. Flexural elasticity was measured.

1 structure protection sheet 2 resin layer 3 polymer cement hardened layer 5 non-woven fabric layer 21 structure 21' concrete composition (structure-forming composition)
22 Undercoat layer
23 Adhesive
24 Formwork

Claims (6)

A structure protection sheet comprising a polymer cement hardened layer provided on the structure side and a resin layer provided on the polymer cement hardened layer,
having a nonwoven fabric layer in the polymer cement hardened layer or at a position in contact with the polymer cement hardened layer;
The tensile modulus at elongation of 1% is 100 to 300 MPa,
A test piece with a width of 10 mm and a length of 60 mm was cut out, and one end of the test piece was fixed to a fixing base up to 10 mm. A structure protection sheet, wherein the distance from the other end, which is a free end, to the fixed base is 30 mm or less. 2. The structure protection sheet according to claim 1, wherein said non-woven fabric layer has a structure in which fibers selected from inorganic fibers, organic fibers, and inorganic and organic mixed fibers are formed into a sheet without weaving. 3. The structure protection sheet according to claim 1, wherein said polymer cement hardening layer is a layer containing a cement component and a resin, and said resin is contained in an amount of 10% by weight or more and 40% by weight or less. 3. A method for manufacturing a reinforced structure using the structure protection sheet according to claim 1 or 2, wherein the structure protection sheet is laminated after applying an adhesive to the structure. a method of manufacturing a constructed structure. 5. A method of making a reinforced structure according to claim 4, wherein a primer layer is provided between said structure and said adhesive. 3. A method for manufacturing a reinforced structure using the structure protection sheet according to claim 1 or 2, wherein an adhesive is applied to the surface of the structure protection sheet where the polymer cement hardened layer is exposed to adhere. A method for producing a reinforced structure, comprising forming an adhesive layer and adhering the structure protection sheet so that the pressure-sensitive adhesive layer is in contact with the surface of the structure.

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