Release film for curing, method for curing adhesive resin, method for applying fiber sheet, and method for repairing structure

Abstract

To suppress both the occurrence of an amine blushing phenomenon and the occurrence of air pockets, and to enhance interlayer adhesion between a plurality of adhesive resins that are applied in layers.SOLUTION: A release film for curing 10 has a resin film body 11 that covers a surface of an adhesive resin while isolating it from the atmosphere, and a plurality of micro holes 12 that are opened at a regular pitch in the film body 11 to allow air to be exhausted. After covering and curing each of the adhesive resins 30a to 30d, the release film for curing 10 is peeled off.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a release film for curing, a method for curing an adhesive resin, a method for applying a fiber sheet, and a method for repairing a structure. [Background technology]

[0002] A known repair technique for structures with attached fiber sheets involves first applying a primer to the surface of the structure, then attaching a fiber sheet, and impregnating the sheet with an epoxy resin-based adhesive resin applied to the fiber sheet and allowing it to harden (Patent Document 1). During construction, when attaching a fiber sheet using an adhesive resin, it is known that carbon dioxide and moisture in the air react with the amines in the adhesive resin, forming a brittle layer of impurities (amine blushing layer) on the surface of the adhesive resin. If the fiber sheet is attached without removing the brittle layer, the interlayer adhesion is impaired, causing the fiber sheet layers to lift or peel off.

[0003] In order to solve such problems, Patent Document 1 discloses a method of removing the fragile layer by using a fiber release sheet. Specifically, when attaching a fiber sheet to the surface of a structure, a fiber release sheet is pressed against the adhesive surface before the adhesive resin hardens, causing the brittle layer formed on the surface of the adhesive resin to penetrate into the fiber release sheet, and the fiber release sheet is then peeled off after the adhesive resin has hardened, thereby removing the brittle layer.

[0004] Furthermore, Patent Document 2 discloses a method of suppressing the occurrence of the amine blushing phenomenon by covering the surface of the adhesive resin with a non-breathable release sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7153995 [Patent Document 2] JP 2002-235444 A Summary of the Invention [Problem to be solved by the invention]

[0006] The fiber release sheet described in Patent Document 1 has the following problems. <1> If you try to peel off the release sheet when the surface of the applied adhesive resin is still tacky, the release sheet will be difficult to peel off. Particularly when construction is carried out during the cold winter months, the time required for the applied adhesive resin to harden increases. Therefore, since the adhesive resin must be allowed to harden sufficiently before it can be peeled off, it takes a long time to complete the peeling of the release sheet, which causes delays in construction. <2> Since the fiber release sheet has excellent impregnation properties with adhesive resin, the impregnated adhesive resin is peeled off when the release sheet is peeled off, and the amount of adhesive resin remaining on the structural part side is greatly reduced.

[0007] The release sheet described in Patent Document 2 has the following problems. <1> Because the release sheet has no breathability, it can prevent the occurrence of the amine blushing phenomenon, but on the other hand, air pockets form on the application surface, reducing the quality of the applied surface. For this reason, it is difficult to simultaneously suppress the occurrence of the amine blushing phenomenon and the occurrence of air pockets. <2> When the release sheet is peeled off, the surface of the adhesive resin becomes like a mirror, which deteriorates the mechanical adhesion when joining the next layer, resulting in low interlayer adhesion.

[0008] The present invention aims to provide a release film for curing, a method for curing an adhesive resin, a method for applying a fiber sheet, and a method for repairing a structure, which can solve the above-mentioned problems. [Means for solving the problem]

[0009] The present invention is a release film for curing that covers and cures adhesive resin applied to reinforce or repair a structure, the release film for curing having a resin film body that covers the surface of the adhesive resin and isolates it from the atmosphere, and a plurality of micropores that are opened at a constant pitch in the film body to allow air to be exhausted and that form a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin, the film body being peelable from the surface of the adhesive resin and from the plurality of protrusions after the adhesive resin has been cured. In another embodiment of the present invention, the aperture d of the micropores 12 is in the range of 50 to 800 μm, and the formation pitch of the micropores is in the range of 0.5 to 20 mm. The present invention is a method for curing an adhesive resin, which involves covering the surface of the adhesive resin with a curing release film and peeling off the curing release film after a curing period has elapsed, and includes the steps of covering the surface of the adhesive resin with the curing release film and curing it, peeling off the curing release film after curing the adhesive resin and forming a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin, and laminating and adhering a separate adhesive resin to the surface of the existing adhesive resin on which the plurality of protrusions have been formed. The present invention is a method for installing a fiber sheet, in which a protective release film and a fiber sheet are used in combination to impregnate the fiber sheet with an adhesive resin applied to the structure and then affixed to the structure, comprising the steps of covering the surface of the adhesive resin with the protective release film described in claim 1 and curing it, peeling off the protective release film after curing the adhesive resin and forming a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin, and impregnating and adhering a separate adhesive resin to the surface of the existing adhesive resin on which the plurality of protrusions have been formed, thereby affixing the fiber sheet to the structure. In another embodiment of the present invention, a step of curing the adhesive resin using the release film for curing and a step of peeling off the release film for curing may be repeated to impregnate and bond a plurality of laminated fiber sheets. The present invention is a method for repairing a structure by covering the surface of the structure with an adhesive resin, which comprises the steps of: applying an adhesive resin to the surface of the structure, covering the surface of the adhesive resin with the curing release film described in claim 1 and curing it; peeling off the curing release film after curing the adhesive resin to form a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin; and applying a separate adhesive resin to the surface of the adhesive resin on which the plurality of protrusions have been formed, and repeating these steps to form a plurality of adhesive resins laminated together. Effect of the Invention

[0010] The present invention has at least one of the following advantages. <1> The protective release film is capable of suppressing both the occurrence of the amine blushing phenomenon and the occurrence of air pockets, and therefore allows the surface of the adhesive resin to be protected to a higher quality than before. <2> The multiple protrusions formed on the surface of the adhesive resin after the protective release film is peeled off act like dowel muscles when joining the next layer of adhesive resin, so that the interlayer adhesion is significantly improved when multiple layers of adhesive resin are applied in layers. <3> The release film for curing can be peeled off by itself even if the adhesive resin has tack on its surface. Therefore, even when application is made in a low-temperature environment where the adhesive resin requires a long time to harden, the release film can be easily peeled off without waiting for complete hardening, thereby shortening the application period of the adhesive resin compared to conventional methods. <4> The protective release film is highly versatile and can be used not only in a method for reinforcing a structure, in which an adhesive resin is impregnated into a fiber sheet and adhered to the structure, but also in a method for repairing a structure, in which an adhesive resin is repeatedly applied to the surface of the structure. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an enlarged perspective view of a release film for curing according to the present invention with a portion omitted. [Diagram 2] An explanatory diagram of the process of adhering a fiber sheet using a protective release film [Diagram 3] Cross-sectional view of the structure and fiber sheet attached [Figure 4] Cross-sectional view of a release film and a structure to explain the curing effect of the release film [Diagram 5] Cross-sectional view of the adhesive resin surface when the protective release film is peeled off [Figure 6] A model diagram of another embodiment applied to a method for repairing a structure in which only adhesive resin is applied to the surface of the structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will now be described with reference to the drawings. In this example, a form will be described in which a release film 10 for protection (hereinafter referred to as "release film 10") and a liquid or putty-like adhesive resin 30 are used in combination to attach a fiber sheet 20 to a structure 40 for reinforcement.

[0013] <1> Release film Conventional release sheets are fibrous sheets that are used on the premise that weak parts will be formed on the surface of the adhesive resin, and the weak parts formed on the surface of the uncured adhesive resin are impregnated into the interior of the fibrous sheet.

[0014] The release film 10 used in the present invention is a film for preventing the formation of weak parts on the surface of the adhesive resin 30, and has a porous structure.

[0015] That is, the release film 10 has a film body 11 having a shielding function, and a plurality of micropores 12 formed in the film body 11 at predetermined intervals.

[0016] <1.1> Film body The film body 11 is not impregnated with the adhesive resin 30 and does not have the water permeability and air permeability required to cover the surface of the adhesive resin 30 . The reason why a non-breathable film is used as the material for the film body 11 is to prevent the occurrence of the amine blushing phenomenon by insulating the surface of the adhesive resin 30 from the atmosphere.

[0017] The film body 11 may be made of a material such as an OPP film (biaxially oriented polypropylene film), a PET film, or a PP film. For practical purposes, OPP film is the most suitable. OPP film, which is made by stretching and processing polypropylene material, is not only strong and tear-resistant, but also highly transparent.

[0018] The sheet thickness t of the film body 11 is 25 to 100 μm, and in practice, 50 to 60 μm is preferable. If the sheet thickness t of the film body 11 is less than 25 μm, the film itself will not have enough stiffness and will easily wrinkle when applied. If the sheet thickness t of the film body 11 is greater than 100 μm, the film will be too stiff and will have difficulty conforming to uneven surfaces.

[0019] <1.2> Micropore The micro holes 12 function to form raised protrusions 31 in the adhesive resin 30 in addition to the air vent function. The planar shape of the micropores 12 is not particularly limited, but taking into consideration processability and the like, the planar shape is preferably circular.

[0020] <1.2.1> Micropore diameter The diameter d of the micropores 12 is preferably in the range of 50 to 800 μm, and more preferably in the range of 50 to 150 μm.

[0021] If the diameter d of the micropores 12 is smaller than 50 μm, it is difficult to manufacture the micropores 12 themselves. If the aperture d of the micropores 12 is greater than 800 μm, too much of the adhesive will come out onto the front side of the film body 11 .

[0022] <1.2.2> Micropore formation pitch The formation pitch p of the micropores 12 is preferably 0.5 to 20 mm, and more preferably in the range of 0.5 to 5 mm.

[0023] If the pitch of the micropores 12 is greater than 20 mm, the deaeration property becomes poor and air tends to remain. If the pitch of the micropores 12 is smaller than 0.5 mm, the hole area ratio becomes large and the film itself becomes easily avoided.

[0024] <1.2.3> Hole area ratio of micropores The hole area ratio of the micropores 12 is preferably 0.10 to 4.0% with an aperture d of less than 800 μm, and more preferably in the range of 0.2 to 2.0%. If the hole area ratio of the micropores 12 is greater than 4.0%, the contact area with the atmosphere becomes large, resulting in poorer suppression of amine blushing and increased overflow of the adhesive resin onto the surface, resulting in poor workability. If the hole area ratio of the micropores 12 is less than 0.10%, there is a problem that workability such as air removal is deteriorated.

[0025] <2> Fiber Sheet The fiber sheet 20 is a sheet-like material intended for reinforcement or repair, and is adhered via an adhesive resin 30 for the purposes of reinforcing a structure 40 or preventing concrete pieces from peeling off, and has a woven, knitted, or laminated structure. The fibrous sheet 20 may be either a unidirectional sheet or a bidirectional sheet. The material of the fiber sheet 20 may be, for example, carbon fiber, aramid fiber, glass fiber, Basalt fiber, vinylon fiber, polyester fiber, olefin-based organic fiber, etc. can be used.

[0026] <3> adhesive resin The primer 30a, the putty 30b, the impregnating adhesive resins 30c, 30d, . . . are resin-based adhesives, and for example, solvent-free liquid epoxy resins that cure at room temperature and use amines as a hardener are used. The amines used as the curing agent are not particularly limited as long as they can cure the adhesive at room temperature, and can be arbitrarily selected from, for example, aliphatic polyamines, alicyclic polyamines, modified polyamines, polymercaptans, polyamides, and the like.

[0027] <4> structure The structure 40 includes a concrete structure, a steel structure, and the like. Examples of concrete structures include bridges, bridge piers, and tunnel lining walls.

[0028] [How to install fiber sheets] A method of applying the fiber sheet 20 using the release film 10 will be described with reference to FIGS.

[0029] 1. Preparation of the structure The structure 40 is prepared through the following steps.

[0030] <1> Primer applicator After performing a surface preparation (cleaning) to remove protrusions and various deposits on the surface of the structure 40, a primer 30a, which is a type of adhesive resin, is applied to the surface of the structure 40. As the primer 30a, a liquid epoxy resin that cures at room temperature can be used.

[0031] The surface of the primer 30a in an unhardened state is covered with a release film 10 and dried and cured in a state cut off from the atmosphere, after which the release film 10 is peeled off.

[0032] The various functions of the release film 10 during curing will be described later.

[0033] <2> Putty processing Putty 30b, which is a type of adhesive resin, is applied to the surface of the primer 30a with a spatula or the like to correct unevenness. The putty 30b may be made of a liquid epoxy resin that hardens at room temperature.

[0034] Similarly, in the case of the putty 30b, the surface is covered with the release film 10 and dried and cured, and then the release film 10 is peeled off. The putty process is not an essential step and may be omitted.

[0035] 2. Fiber sheet attachment process The fiber sheet or sheets 20 are attached through the following steps.

[0036] <1> Undercoat of adhesive resin The surface of the putty 30b is coated with an impregnating adhesive resin 30c as a primer.

[0037] <2> Adhesion of fiber sheets and topcoat of adhesive resin The surface of the undercoated impregnating adhesive resin 30c is impregnated with the fiber sheet 20, and then the fiber sheet 20 is coated with a topcoat of impregnating adhesive resin 30d.

[0038] Similarly, in the case of the topcoated adhesive resin 30d, the surface is covered with the release film 10 and dried and cured, after which the release film 10 is peeled off.

[0039] <3> Attachment of multiple fiber sheets When a plurality of fiber sheets 20 are laminated and attached, the above steps are repeated. FIG. 3 shows a configuration in which two fiber sheets 20 are laminated and attached.

[0040] 3. Protective effect of release film In the following description, the primer 30a, putty 30b, and impregnating adhesive resins 30c, 30d will be collectively referred to as adhesive resin 30. With reference to FIG. 4, the curing effect of the release film 10 covered with the adhesive resin 30 will be described. In FIG. 4, in order to make the structure easier to understand, a gap is shown between the adhesive resin 30 and the release film 10, but in reality, the adhesive resin 30 and the release film 10 are in close contact with each other and no gap is created.

[0041] <1> Contact area between release film and adhesive resin The entire surface of the adhesive resin 30 is covered with the film body 11 constituting the release film 10 . Since the hole area ratio of the group of microholes 12 formed in the film body 11 is very small, the effect of the group of microholes 12 on the interlayer adhesion between the surface of the adhesive resin 30 and the film body 11 is very small. Therefore, even if the film body 11 has micropores 12 formed therein, the adhesion between the release film 10 and the adhesive resin 30 is not impaired.

[0042] <2> Prevents the occurrence of amine blushing phenomenon The entire surface of the adhesive resin 30 is covered with the film body 11 having a shielding function, thereby blocking contact between the adhesive resin 30 and the atmosphere. Therefore, the amine in the adhesive resin 30 is prevented from coming into contact with moisture and carbon dioxide, so that the occurrence of the blushing phenomenon can be effectively suppressed.

[0043] Since the hole area ratio of the group of micropores 12 opened in the adhesive resin 30 is set to be very small, an amine brushing layer is not formed on the surface of the adhesive resin 30 through the micropores 12 .

[0044] <3> Release film helps remove air bubbles Air bubbles may be present between the surface of the adhesive resin 30 and the film body 11. Even if air bubbles are generated, they can be reliably exhausted (defoamed) to the outside through the micropores 12. The pitch of the micro holes 12 is selected so that air bubbles generated wherever they occur can be discharged through the micro holes 12, thereby reliably preventing the generation of air pockets.

[0045] <4> Formation of protrusions by micro-holes A portion of the adhesive resin 30 flows into the micropores 12 formed in the release film 10 , forming raised protrusions 31 on the surface of the adhesive resin 30 .

[0046] <5> Sealing effect (prevents resin from whitening) For example, when the adhesive resin 30 comes into contact with moisture such as rainwater or condensation, the resin surface turns white. Since the whitened resin is structurally weak, it is necessary to remove the whitened areas using sandpaper or the like.

[0047] In the present invention, the release film 10 seals the surface of the adhesive resin 30, preventing contact with moisture such as rainwater and condensation. The micropores 12 formed in the release film 10 have a very small diameter, so that water can be prevented from penetrating inward through the micropores 12 . Therefore, whitening of the adhesive resin 30 can be prevented, and the work of removing the whitened resin at the site is not required.

[0048] <6> Leakage of adhesive resin through micropores If the diameter of the micropores 12 is too large, there is a risk that the adhesive resin 30 will leak to the outside through the micropores 12. In the present invention, the aperture of the micropores 12 is set to a size that does not allow the resin to easily pass through the micropores 12, and the adhesive resin 30 has a certain degree of viscosity. Therefore, even if the release film 10 is pressed, there is no risk of the adhesive resin 30 leaking out through the micropores 12.

[0049] 4. Remove the release film The peeling of the release film 10 will be described with reference to FIG.

[0050] <1> Removal of release film When the adhesive resin 30 has hardened to a certain extent, the release film 10 is forcibly peeled off. Where the film body 11 is peeled off, a smooth surface of the unweakened adhesive resin 30 appears, and where the micropores 12 are peeled off, raised protrusions 31 appear.

[0051] <2> When to remove the release film Conventionally, if a release sheet was peeled off when the adhesive resin had tack on its surface, the good quality adhesive resin would also be peeled off, so it was necessary to wait until the adhesive resin hardened before peeling off the release sheet. In particular, in low temperature environments such as winter, it takes a long time for the adhesive resin to harden, which makes construction time longer.

[0052] In contrast, the release film 10 of the present invention is not impregnated with the adhesive resin 30, and therefore the release film 10 can be easily peeled off even if the adhesive resin 30 has tack on its surface. That is, since the adhesive resin 30 does not permeate the inside of the release film 10, it is possible to prevent the applied adhesive resin 30 from being torn off when the release film 10 is peeled off. In the present invention, when construction is performed in a low temperature environment, the release film 10 can be easily peeled off without waiting for the adhesive resin 30 to completely harden, so that the construction period can be shortened compared to the conventional case.

[0053] <3> Interlayer adhesion After the release film 10 is peeled off, a large number of protrusions 31 are formed on the surface of the adhesive resin 30 so as to protrude therefrom. The numerous protrusions 31 formed on the surface of the adhesive resin 30 function like dowel muscles when joining the next layer of adhesive resin 30, improving interlayer adhesion compared to when the protrusions 31 are not formed (Figure 3).

[0054] 5.Lamination of fiber sheets To laminate and attach a plurality of fiber sheets 20, the above-described steps of attaching and peeling the release film 10 are repeated each time a fiber sheet 20 is attached (FIG. 3). The number of layers of the fiber sheets 20 can be appropriately selected.

[0055] The entire surface of the uppermost adhesive resin 30 is finished to be smooth.

[0056] [Other Examples] In the previous embodiment, a form in which a fiber sheet 20 is attached to a structure 40 by using a release film 10 and an adhesive resin 30 in combination was described. However, it is also possible to apply the present invention to a form in which repair is performed by applying adhesive resin 30 (30e, 30f) to the surface of a structure 40 without using a fiber sheet 20.

[0057] <1> How to repair a structure This embodiment will be described in detail with reference to FIG. In this example, after applying adhesive resin 30e to the surface of the structure 40, the following steps are carried out: covering the surface of the adhesive resin 30e with a curing release film 10 and curing it; peeling off the curing release film 10 after curing the adhesive resin 30e to form a plurality of protrusions 31 integrally with the adhesive resin 30e on the surface of the adhesive resin 30e; and applying a separate adhesive resin 30f to the surface of the adhesive resin 30e, thereby forming a plurality of adhesive resins 30e, 30f by stacking them together. In this example, two layers of adhesive resin 30e, 30f are laminated, but the number of layers of adhesive resin can be appropriately selected.

[0058] <2> Protective effect of release film In this embodiment, the protective effect of the adhesive resin by the release film 10 is the same as in the previous embodiment.

[0059] <3> Effects of this embodiment In this embodiment, the surface of the structure 40 can be repaired by coating it with a good quality adhesive resin that does not have a brittle layer. In particular, the present invention can be applied to a peeling prevention method in which the surface of a structure 40 such as an aged concrete tunnel is covered with adhesive resin 30. [Explanation of symbols]

[0060] 10....Curtain release film (release film) 11. Film body 12... Micropore 20... Fiber sheet 30...Adhesive resin 30a····Primer (adhesive resin) 30b Putty (adhesive resin) 30c...Impregnated adhesive resin 30d...Impregnating adhesive resin 30e...Adhesive resin 30f...Adhesive resin 31... Projection 40...Structures

Claims

1. A release film for curing that covers and cures an adhesive resin applied to reinforce or repair a structure, A resin film body in which the protective release film covers the surface of the adhesive resin while isolating it from the atmosphere; the film body has holes at a constant pitch that allow air to be exhausted, and a plurality of minute holes are provided on the surface of the adhesive resin that integrally form a plurality of protrusions with the adhesive resin; The film body is characterized in that it can be peeled off from the surface of the adhesive resin and the multiple protrusions after the adhesive resin has cured. Release film for protective purposes.

2. 2. The release film for curing according to claim 1, characterized in that the aperture of the micropores is in the range of 50 to 800 μm, and the formation pitch of the micropores is in the range of 0.5 to 20 mm.

3. A method for curing an adhesive resin, comprising covering a surface of the adhesive resin with a release film for curing, and peeling off the release film for curing after a curing period has elapsed, A step of covering the surface of the adhesive resin with the release film for curing according to claim 1 and curing the surface; a step of peeling off the release film after curing the adhesive resin to form a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin; and a step of laminating and adhering a separate adhesive resin onto the surface of the existing adhesive resin on which the plurality of protrusions are formed. How to cure adhesive resin.

4. A method for attaching a fiber sheet to a structure by using a release film for curing and a fiber sheet in combination and impregnating the fiber sheet with an adhesive resin applied to the structure, comprising: A step of covering the surface of the adhesive resin with the release film for curing according to claim 1 and curing the surface; a step of peeling off the release film after curing the adhesive resin to form a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin; The surface of the existing adhesive resin on which the plurality of protrusions are formed is impregnated with a separate adhesive resin to adhere the fiber sheet to the structure. How to install fiber sheets.

5. The method for applying a fiber sheet according to claim 4, characterized in that a step of curing the adhesive resin using the release film for curing and a step of peeling off the release film for curing are repeated to impregnate and bond a plurality of laminated fiber sheets.

6. A method for repairing a structure by coating a surface of the structure with an adhesive resin, comprising the steps of: After applying an adhesive resin to the surface of the structure, A step of covering the surface of the adhesive resin with the release film for curing according to claim 1 and curing the surface; a step of peeling off the release film after curing the adhesive resin to form a plurality of protrusions integrally with the adhesive resin on the surface of the adhesive resin; and applying a separate adhesive resin to the surface of the adhesive resin on which the plurality of protrusions are formed. How to repair a structure.

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