Adhesive sheet and adhesion method

Abstract

To provide a bonding technique capable of solving problems in the prior art, that is, capable of arranging a curable composition between members while obtaining the uniform thickness of the curable composition.SOLUTION: An adhesive sheet capable of holding a curable composition to bond and fix an adherend includes a first surface material, a second surface material and an intermediate. The adhesive sheet satisfies the requirement that a restoration time until returning to the original state after being bent in the state of holding the curable composition having a predetermined reference viscosity on a test piece having a predetermined flat surface size is equal to or less than a predetermined allowable time.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technique for bonding adherends, and more specifically to an adhesive sheet that holds a curable composition, and a bonding method using the same. [Background technology]

[0002] Production facilities such as factories generally have a steel frame structure, which is primarily made up of steel materials such as H-shaped steel and steel pipes, and is constructed by combining steel columns, beams, diagonal members, etc. For example, this steel frame structure can be constructed by attaching beams made of H-shaped steel to columns made of H-shaped steel, and then attaching diagonal members made of channel steel or angle steel to the columns and beams.

[0003] Traditionally, welding methods such as arc welding have been the mainstream for connecting steel frames and reinforcing materials. However, welding requires the preparation of various tools such as arc welding machines and manual welding torches, and is quite time-consuming, requiring the routing of cabtyre cords, and has the drawback of being limited to workers with special training and experience. For this reason, in recent years, a method of connecting steel frames and reinforcing materials with adhesives has also been adopted. Joining with adhesives (hereinafter referred to as "adhesive fixing") is extremely easy and can be done in a short time, does not require limited workers, and does not pose the risk of fire during the work, as occurs with welding.

[0004] However, several problems can be pointed out with adhesive fixing. Compared to electronic components in the industrial sector, components used in the construction industry, such as H-beams and steel pipes, have significantly larger adhesive areas and thicknesses, placing a heavy burden on the person applying the adhesive. While adhesives with low viscosity, such as water, can be easily applied to components with large surfaces, it is not easy to apply the adhesive while ensuring the required thickness. In particular, when adhesive fixing components to tilted components, the adhesive tends to run off, making it extremely difficult to apply the adhesive evenly.

[0005] In addition, steel materials such as H-beams have a certain amount of unevenness (concave and concave) on their surfaces, and it is difficult to apply adhesive evenly while ensuring the required thickness and adapting to these unevenness. Furthermore, if a liquid adhesive is applied directly to the surface of a component, voids (vacuum cavities) may form inside the applied adhesive, which may result in the expected adhesive strength not being achieved.

[0006] Incidentally, so-called "carriers" that can hold liquids inside are already known, and various technologies have been proposed for these carriers. For example, Patent Document 1 proposes a liquid-retaining material that is composed of a three-dimensional knitted fabric made of two knitted fabrics and connecting fibers that connect the knitted fabrics. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-280927 Summary of the Invention [Problem to be solved by the invention]

[0008] The inventors of the present invention have developed a technical concept for using a carrier for adhesive bonding. A carrier of a predetermined thickness is impregnated with an adhesive, and the adhesive-loaded carrier is placed between components to adhesively bond them together. This allows the adhesive to be applied uniformly to tilted components while maintaining the predetermined thickness, and also prevents voids from forming inside the adhesive. However, it is possible that a carrier placed between components to be adhesively bonded may be significantly compressed (crushed) in the thickness direction. For example, even if a 10 mm thick carrier is used to bond steel materials, it may be compressed to about 2 mm by the steel material and then not return to its original thickness. In this case, it may be difficult to apply the adhesive accurately while adapting to the unevenness of the steel surface.

[0009] The object of the present invention is to solve the problems of the conventional technology, that is, to provide an adhesive technology that can arrange a curable composition between members while ensuring a uniform thickness of the curable composition. [Means for solving the problem]

[0010] The present invention was made with a focus on the fact that adherends can be bonded and fixed together using an adhesive sheet that has been confirmed to have a predetermined restoring force, and is based on an unprecedented idea.

[0011] The adhesive sheet of the present invention is capable of holding a curable composition and adhering and fixing an adherend, and comprises a first surface material, a second surface material, and an intermediate. Multiple voids are formed in the first surface material and the second surface material, and an intermediate formed between the first surface material and the second surface material is capable of holding the curable composition. The adhesive sheet of the present invention satisfies the requirement that a test piece of predetermined planar dimensions, impregnated with a curable composition of a predetermined standard viscosity, is folded and then restored to its original state within a predetermined allowable time. Alternatively, the test piece may have planar dimensions of 5 cm x 5 cm, a standard viscosity of 25 Pa·s, and an allowable time of 3 seconds. This test piece has the same configuration as the adhesive sheet of the present invention, i.e., it comprises a first surface material, a second surface material, and an intermediate.

[0012] The adhesive sheet of the present invention can also be one in which the curable composition held on the test specimen is one adhesive selected from the group consisting of acrylic adhesives, epoxy adhesives, modified silicone adhesives, silicone adhesives, urethane adhesives, and polyester adhesives, or an adhesive consisting of a combination of two or more adhesives.

[0013] In the adhesive sheet of the present invention, the curable composition held on the test specimen can be one adhesive selected from the group consisting of one component heat-curing epoxy adhesive, one component moisture-curing acrylic-modified silicone adhesive, one component moisture-curing modified silicone adhesive, two component mixing curing modified silicone adhesive, one component moisture-curing silicone adhesive, two component mixing curing silicone adhesive, two component mixing moisture-curing epoxy-modified silicone adhesive, two component mixing curing epoxy adhesive, one component anaerobic curing acrylic adhesive, two component mixing fast-curing acrylic adhesive, two component mixing slow-curing acrylic adhesive, one component moisture-curing urethane adhesive, and two component mixing curing urethane adhesive.

[0014] The adhesive sheet of the present invention can also have a three-dimensional knit structure in which the first surface material and the second surface material are connected by connecting yarns, in which case the intermediate body is formed by a plurality of connecting yarns.

[0015] The adhesive sheet of the present invention may have a three-dimensional knit structure in which the first surface material and the second surface material are connected by a connecting yarn, in which case the first surface material, the second surface material, and the connecting yarn may each be formed from either a synthetic monofilament yarn or a synthetic multifilament yarn.

[0016] The bonding method of the present invention is a method for adhering and fixing an adherend using the adhesive sheet of the present invention, and includes an adhesive sheet testing step, a curable composition impregnation step, and an adhesive sheet installation step. In the adhesive sheet testing step, a test specimen of the adhesive sheet is tested to determine whether it is pass or fail. In the curable composition impregnation step, an adhesive sheet determined to be pass or fail in the adhesive sheet testing step is impregnated with a curable composition, and in the adhesive sheet installation step, the adhesive sheet holding the curable composition is installed on the surface of the adherend. In the adhesive sheet testing step, a specimen of predetermined planar dimensions is bent while holding a curable composition of a predetermined standard viscosity, and the adhesive sheet is judged pass if its recovery time to its original state is within a predetermined allowable recovery time. If the recovery time exceeds the allowable recovery time, the adhesive sheet is judged fail. The adhesive sheet testing step can also be performed with a specimen of 5 cm x 5 cm planar dimensions, a standard viscosity of 25 Pa·s, and an allowable recovery time of 3 seconds.

[0017] The bonding method of the present invention can also be a method for judging the suitability of an adhesive sheet based on the exudation time in addition to the recovery time. In this case, in the adhesive sheet testing step, after impregnating a test specimen with a curable composition of a standard viscosity, if the exudation time until the curable composition exudes from the test specimen is equal to or shorter than a predetermined allowable exudation time, the adhesive sheet is judged as suitable, and if the exudation time exceeds the allowable exudation time, the adhesive sheet is judged as unsuitable.

[0018] The bonding method of the present invention can also be a method using, as the curable composition, one adhesive selected from acrylic adhesives, epoxy adhesives, modified silicone adhesives, silicone adhesives, urethane adhesives, and polyester adhesives, or an adhesive consisting of a combination of two or more adhesives.

[0019] The bonding method of the present invention can also be a method using, as the curable composition, one adhesive or a combination of two or more adhesives selected from one-component heat-curing epoxy adhesives, one-component moisture-curing acrylic-modified silicone adhesives, one-component moisture-curing modified silicone adhesives, two-component mixing curing modified silicone adhesives, one-component moisture-curing silicone adhesives, two-component mixing curing silicone adhesives, two-component mixing moisture-curing epoxy-modified silicone adhesives, two-component mixing curing epoxy adhesives, one-component anaerobic-curing acrylic adhesives, two-component mixing fast-curing acrylic adhesives, two-component mixing slow-curing acrylic adhesives, one-component moisture-curing urethane adhesives, and two-component mixing curing urethane adhesives. [Effects of the Invention]

[0020] The adhesive sheet and adhesive method of the present invention have the following effects. (1) The adhesive fixing work can be performed without placing a heavy burden on the worker. (2) Even when the member is in an inclined position, the adhesive can be applied uniformly while ensuring a predetermined thickness. (3) It is also possible to suppress the occurrence of voids inside the adhesive, and as a result, it is expected that the intended adhesive strength will be fully exerted. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a partial cross-sectional view schematically showing an H-shaped steel beam and an angle steel beam bonded and fixed together with an adhesive sheet according to the present invention. [Figure 2] 1 is a perspective view schematically showing an adhesive sheet according to the present invention. [Figure 3] (a) is a plan view showing a schematic representation of a rectangular void, and (b) is a plan view showing a schematic representation of a hexagonal void. [Figure 4] (a) is a cross-sectional view showing a schematic diagram of an adhesive sheet with a three-dimensional knitted structure in its normal state (uncompressed state), and (b) is a cross-sectional view showing a schematic diagram of an adhesive sheet with a three-dimensional knitted structure in a compressed state. [Figure 5] 1 is a flow chart showing the flow of main steps in the bonding method of the present invention. [Figure 6] 10A to 10C are graphs showing experimental results of various evaluations of adhesive bonding according to the present invention. [Figure 7] FIG. 10 is a graph showing the results of an experiment in which a recovery test was performed on an adhesive bond according to the present invention. [Figure 8] FIG. 10 is a diagram showing the experimental results of evaluations of adhesive bonding using various adhesives. [Figure 9] A schematic diagram of the research experiment conducted to measure tensile shear bond strength. DETAILED DESCRIPTION OF THE INVENTION

[0022] An example of an embodiment of the adhesive sheet and bonding method of the present invention will be described with reference to the drawings.

[0023] 1.Overview The present invention relates to a technology for joining (i.e., adhesively fixing) a member such as an H-shaped steel beam (hereinafter, for convenience, referred to as the "first member EL1") to a member such as an angle steel beam (hereinafter, for convenience, referred to as the "second member EL2") using a curable composition (e.g., an adhesive). However, adhesive fixing is performed using an adhesive sheet 100 of the present invention, as shown in FIG. 1. More specifically, the first member EL1 and the second member EL2 are adhesively fixed by placing the adhesive sheet 100 holding the curable composition. This allows the adhesive to be uniformly distributed (applied, so to speak) while ensuring a predetermined thickness. While FIG. 1 shows an example of adhesively fixing an H-shaped steel beam to an angle steel beam, the present invention can be used to adhesively fix members made of various materials, including not only steel (e.g., SS400) but also resins.

[0024] 2. Adhesive sheet Next, the adhesive sheet 100 of the present invention will be described in detail. The adhesion method of the present invention is a method of adhesively fixing components together using the adhesive sheet 100 of the present invention. Therefore, the adhesive sheet 100 of the present invention will be described first, and then the adhesion method of the present invention will be described.

[0025] FIG. 2 is a perspective view schematically illustrating an adhesive sheet 100 of the present invention. As shown in this figure, the adhesive sheet 100 comprises a first surface member 110, a second surface member 120 (i.e., the front and back surfaces), and an intermediate member 130 formed between the first surface member 110 and the second surface member 120. As shown in FIG. 3, a plurality of voids 111 are formed in the first surface member 110 and the second surface member 120. The voids 111 can have various shapes; for example, FIG. 3(a) shows rectangular voids 111, and FIG. 3(b) shows hexagonal voids 111. Of course, the voids 111 of the same shape can be formed in the first surface member 110 and the second surface member 120, or the voids 111 of different shapes can be formed in the first surface member 110 and the second surface member 120. The first surface material 110 and the second surface material 120 can be made of various conventionally used materials, but research and experiments conducted by the inventors of the present invention have confirmed that it is particularly suitable to form them from synthetic monofilament yarn or synthetic multifilament yarn.

[0026] When adhesive sheet 100 is impregnated with a curable composition (e.g., an adhesive), intermediate 130 can hold the curable composition. Then, when adhesive sheet 100 is placed between first member EL1 and second member EL2 while intermediate 130 holds the curable composition, as shown in Figure 1, the curable composition seeps out from gaps 111 in first surface member 110 and second surface member 120, and as a result, first member EL1 and second member EL2 are adhered and fixed via adhesive sheet 100.

[0027] As mentioned above, the adhesive sheet 100 placed between the first member EL1 and the second member EL2 to be bonded and fixed may be significantly compressed (crushed) in the thickness direction. If the sheet remains compressed and does not recover (does not return to its original thickness), it may not be possible to apply the adhesive properly while adapting to the unevenness of the steel surface. Therefore, the adhesive sheet 100 of the present invention is designed to have a considerable restoring force (hereinafter referred to as the "target restoring force"). In other words, the adhesive sheet 100 of the present invention is one that has been confirmed to have the target restoring force.

[0028] To confirm the target restoring force, a restoration test can be performed. The procedure for performing the restoration test is described below. First, a test specimen having predetermined planar dimensions (hereinafter referred to as "reference dimensions") is impregnated with a curable composition having a predetermined viscosity (hereinafter referred to as "reference viscosity"), and this curable composition is held by an intermediate 130. Note that the test specimen here has a similar structure to the adhesive sheet 100, but since the target restoring force has not yet been confirmed, it can be considered a provisional adhesive sheet 100. Then, with the curable composition held, the first surface member 110 (or the second surface member 120) of the test specimen is folded in half, and the time it takes for the specimen to return to its original state (hereinafter referred to as the "restoring time") is measured. If the restoring time is equal to or shorter than the predetermined time (hereinafter referred to as the "allowable restoring time"), it is determined that the test specimen has the target restoring force (i.e., can be used as the adhesive sheet 100 of the present invention). If not, it is determined that the test specimen does not have the target restoring force (i.e., cannot be used as the adhesive sheet 100 of the present invention).

[0029] For example, a test specimen with standard dimensions of 5 x 5 cm can be impregnated with an adhesive with a standard viscosity of 25 Pa·s and folded in half. If the recovery time is 3 seconds or less (the allowable recovery time), it is determined to have the target recovery force; otherwise, it is determined to not have the target recovery force. The standard dimensions of the test specimen are not limited to 5 x 5 cm and can be set in the range of 3 to 25 cm (i.e., 3 to 25 x 3 to 25 cm), and a curable composition (adhesive) with a standard viscosity of 5 to 100 Pa·s can also be used. Furthermore, the allowable recovery time is not limited to 3 seconds and can be set in the range of 2 to 5 seconds.

[0030] The inventors of the present invention have discovered that a three-dimensional knit structure such as that shown in FIG. 4 improves the restoring force, i.e., makes it easier to use as an adhesive sheet 100. This three-dimensional knit structure is a structure with multiple connecting threads 131, as shown in FIG. 4. More specifically, the multiple connecting threads 131 connect the first surface material 110 and the second surface material 120, and a predetermined space (i.e., an intermediate body 130) is formed between the first surface material 110 and the second surface material 120. Each connecting thread 131 is arranged so as to bend in a normal (uncompressed) state, as shown in FIG. 4(a). When compressed, as shown in FIG. 4(b), the connecting threads 131 bend even more, thereby enabling the fabric to exert a large restoring force. Note that the connecting threads 131 can be made of various conventional materials, but research and experiments conducted by the inventors of the present invention have confirmed that they are particularly suitable when made of synthetic monofilament yarn or synthetic multifilament yarn.

[0031] Incidentally, when adhesive sheet 100 is placed between first member EL1 and second member EL2 and compressive force due to the weight of first member EL1 or second member EL2 acts, poor adhesion may occur unless the curable composition properly seeps out not only from the sides of adhesive sheet 100 (particularly intermediate 130) but also from gaps 111 between first surface member 110 and second surface member 120. Therefore, adhesive sheet 100 of the present invention can be one that has a target restoring force as well as a corresponding fluidity of the curable composition (hereinafter referred to as "target fluidity"). In other words, adhesive sheets that have confirmed the target restoring force and target fluidity are adopted as adhesive sheets 100 of the present invention.

[0032] To confirm the target fluidity, it is advisable to conduct an exudation test. The procedure for conducting an exudation test is described below. First, a test specimen is immersed in a curable composition of standard viscosity, and this curable composition is held in an intermediate 130. The time (hereinafter referred to as the "exudation time") until the curable composition exudes from the test specimen (particularly the first surface material 110 and the second surface material 120) holding the curable composition is measured. If the exudation time is equal to or shorter than a predetermined time (hereinafter referred to as the "allowable exudation time"), it is determined that the target fluidity is met (i.e., it can be used as the adhesive sheet 100 of the present invention). If not, it is determined that the target fluidity is not met (i.e., it cannot be used as the adhesive sheet 100 of the present invention).

[0033] 3.Adhesion method Next, the bonding method of the present invention will be described with reference to Figure 5. The bonding method of the present invention is a method of bonding and fixing components together using the adhesive sheet 100 described up to this point. Therefore, we will avoid any overlapping explanation with the explanation of the adhesive sheet 100 and will only explain the details unique to the bonding method of the present invention. In other words, the details not described here are the same as those explained in "2. Adhesive Sheet."

[0034] Figure 5 is a flow diagram showing the main steps of the bonding method of the present invention. As shown in this figure, the bonding method of the present invention is roughly divided into a "testing process" in which restoration tests are conducted in advance, and a "bonding process" in which the members are actually bonded and fixed together on site.

[0035] (Testing process) First, if there are multiple types of test specimens, the desired test specimen is selected (Step 211 in Fig. 5). Of course, this step is omitted when conducting a test on test specimen 1. Once the test specimen is selected, a recovery test (Step 212 in Fig. 5) is performed to confirm the target recovery force. If the recovery time is shorter than the allowable recovery time (Yes in Step 213 in Fig. 5), proceed to the next step. On the other hand, if the recovery time is longer than the allowable recovery time (No in Step 213 in Fig. 5), a new test specimen should be selected (Step 211 in Fig. 5) and a recovery test (Step 212 in Fig. 5) should be performed.

[0036] If the result of the resilience test shows that the resilience time is equal to or less than the allowable resilience time, the test specimen can be used as is to proceed to the bonding step as adhesive sheet 100 of the present invention, or an exudation test (Step 214 in FIG. 5) can be performed before deciding on adhesive sheet 100 of the present invention. When performing an exudation test, if the exudation time is less than the allowable exudation time (Yes in Step 215 in FIG. 5), proceed to the bonding step; on the other hand, if the exudation time is greater than the allowable exudation time (No in Step 215 in FIG. 5), a new test specimen can be selected (Step 211 in FIG. 5) and then the resilience test (Step 212 in FIG. 5) and the exudation test (Step 214 in FIG. 5) can be performed.

[0037] Once the adhesive sheet 100 to be used in the actual bonding process has been determined, this adhesive sheet 100 is impregnated with the planned curable composition (e.g., adhesive) (Step 221 in Figure 5). The curable composition used here can be any of a variety of conventional curable compositions, including acrylic adhesives, epoxy adhesives, modified silicone adhesives, silicone adhesives, urethane adhesives, and polyester adhesives, and curing conditions such as one-component or two-component types can be selected appropriately from the perspective of application. In particular, it is recommended to use one of the following adhesives as the curable composition: One-component heat-curing epoxy adhesive One-component moisture-curing acrylic-modified silicone adhesive One-component moisture-curing modified silicone adhesive Two-component mixed curing modified silicone adhesive One-component moisture-curing silicone adhesive Two-component curing silicone adhesive Two-component moisture-curing epoxy-modified silicone adhesive Two-component curing epoxy adhesive One-component anaerobic curing acrylic adhesive Two-component, fast-curing acrylic adhesive Two-component slow-curing acrylic adhesive One-component moisture-curing urethane adhesive Two-component curing urethane adhesive

[0038] Once the impregnation step has caused the intermediate 130 to retain the curable composition, the adhesive sheet 100 is placed on the first member EL1 (or the second member EL2) (Step 222 in FIG. 5), and the second member EL2 (or the first member EL1) is placed so as to be in contact with the adhesive sheet 100 (Step 223 in FIG. 5). This causes the curable composition to seep out from the gaps 111 in the first surface member 110 and the second surface member 120, and as a result, the first member EL1 and the second member EL2 are adhered and fixed via the adhesive sheet 100.

[0039] (Example of research experiment) The results of research experiments actually conducted by the inventors will now be described. Figure 6 is a diagram of the results of experiments showing various evaluations of adhesive bonding using the present invention. In this research experiment, 17 types of carriers (No. 1 to No. 17) were used as candidates for adhesive sheet 100 to bond and fix components together, and six types of evaluations (Evaluation 1 to Evaluation 6) were conducted, along with confirming whether or not the target tensile shear adhesive strength (in the figure, "adhesive strength") was achieved and the state of the components when they were peeled off (in the figure, "fracture state").

[0040] Four types of three-dimensional knitted support materials were used: Type A to Type D (No. 1 to No. 4). All were manufactured by Asahi Kasei Corporation. Type A was model number AKE65710 (double russell (hexagonal mesh), polyester-polytrimethylene terephthalate (PTT)-polyester), Type B was model number AKE64036 (double russell (hexagonal mesh), polyester-nylon-polyester), Type C was model number AKE65810 (double russell (flat), polyester-polytrimethylene terephthalate (PTT)-polyester), and Type D was model number AKE65910 (double russell (square mesh), polyester-polytrimethylene terephthalate (PTT)-polyester).

[0041] Additionally, four types of polyethylene foam carriers, Type A to Type D (No. 11 to No. 14), are used. All are manufactured by Sanwa Kako Co., Ltd. Type A is model number LC300#3 (semi-open foam sponge, polyethylene), Type B is model number LR300#2 (semi-open foam sponge, polyethylene), Type C is model number LC150#1 (semi-open foam sponge, polyethylene), and Type D is model number LC300#2 (semi-open foam sponge, polyethylene).

[0042] Evaluations 1 to 6 are all rated on a 5-point scale, with higher values indicating higher ratings. Regarding "adhesive strength," a "good" is given if the target tensile shear adhesive strength is met, and an "x" if it is not met. Regarding "failure state," a "deadhesive type" is given if cohesive failure of the adhesive occurs between the carrier surface and the surface of the component, and a "carrier type" is given if cohesive failure of the carrier occurs. "Adhesive type" means that the adhesive's inherent tensile shear adhesive strength is fully exerted, while "carrier type" means that the carrier is destroyed before the tensile shear adhesive strength is exerted.

[0043] Rating 1 evaluates the presence or absence of the target restoring force, and Rating 6 evaluates the presence or absence of the target fluidity. Rating 2 evaluates "liquid absorbency," Rating 3 evaluates "rigidity," Rating 4 evaluates "toughness," and Rating 5 evaluates "supportability." Here, "liquid absorbency" refers to the ability to add and remove liquid when using, for example, a two-component adhesive; the easier it is to add and remove liquid, the higher the rating. "Rigidity" refers to the ease of handling the carrier that holds the adhesive; flexible carriers tend to adhere to workers and contaminate the site, so a carrier without such flexibility receives a higher rating. "Toughness" refers to the resistance to breakage when compressive force is concentrated in a small area of the carrier; the higher this performance, the better the ability to prevent the adhesive from leaking, resulting in a higher rating. "Supportability" refers to the ability to allow liquid to flow under its own weight when installed on an inclined or vertical surface; a high rating is given when sufficient adhesive thickness is ensured to prevent flow.

[0044] Looking at the "total score" calculated by adding up ratings 1 to 6, the three-dimensional knitted structure carriers (No. 1 to No. 4) and the three-dimensional mesh structure carbon fiber (No. 5) all received high scores (i.e., high ratings), and they also had the target tensile shear adhesive strength. The failure state was also "adhesive type (a failure state in which cohesive failure of the adhesive occurred between the carrier surface and the component surface)," indicating that they are highly suitable as adhesive sheets 100 of the present invention. Furthermore, the PET foam carrier (No. 6), high-resilience urethane foam carrier (No. 7), urethane foam carrier (No. 8), natural rubber carrier (No. 9), carbon fiber carrier (No. 10), and glass felt carrier (No. 11) also have relatively high "overall scores," although not as high as the three-dimensional knitted structure carrier, and they have the target tensile shear adhesive strength, and their failure state is "adhesive type (failure state in which cohesive failure of the adhesive occurs between the carrier surface and the component surface)," so it can also be seen that they can be used as adhesive sheets 100 of the present invention.

[0045] As explained above, the suitability of the adhesive sheet 100 of the present invention can be determined using the evaluation point format shown in FIG. 6 , but it can also be determined by quantitative evaluation based on the target restoring force. FIG. 7 is a graph showing the results of a recovery test using the carriers shown in FIG. 6 (excluding Nos. 7, 9, and 11 among Nos. 1 to 17). The "liquid soaking time" in the table refers to the time the carrier is soaked in the adhesive, and the target restoring force is set at 3 seconds. The results of this recovery test show that the recovery times of the carriers with a three-dimensional knit structure (Nos. 1 to 4) are all below the target restoring force (3 seconds), indicating that they can be used as the adhesive sheet 100 of the present invention. Furthermore, the recovery time of the carbon fiber (No. 5), which has a three-dimensional network structure, is also below the target restoring force, indicating that they can also be used as the adhesive sheet 100 of the present invention. It can be seen that the three-dimensional knit structure improves the restoring force, making it easier to use as the adhesive sheet 100.

[0046] The inventors have also conducted research experiments to select a curable composition suitable for the present invention. Figure 8 is a graph showing the results of experiments evaluating adhesive bonding using various adhesives. In these experiments, Type A three-dimensional knitted structure (product number "AKE65710") shown in Figures 6 and 7 was used as the carrier, and experiments were conducted with various adhesives. Figure 8 shows nine adhesives (No. 1 to No. 9) that produced good results. The six types of evaluations (Evaluation 1 to Evaluation 6) shown in Figure 8, as well as "adhesive strength" and "fracture state," are the same as those described in Figure 6, and the evaluation method is also the same as that described in Figure 6.

[0047] The nine adhesives shown in Figure 8 all received high overall scores (i.e., high ratings), had the target tensile shear bond strength, and failed in an adhesive-type state (a state in which cohesive failure of the adhesive occurred between the carrier surface and the member surface). Therefore, it can be seen that these nine adhesives are suitable curable compositions for the present invention.

[0048] To evaluate the "adhesive strength" and "failure state" in Figures 6 and 8, a tensile shear bond strength test was conducted as shown in Figure 9. The actual tensile shear bond strength test will be described below with reference to this figure. First, a support body measuring 25 mm × 25 mm in plan view and 10 mm thick was prepared, and various adhesives were applied to it. Of course, various supports were prepared in the case of Figure 6, and a Type A three-dimensional knitted structure was prepared in the case of Figure 8. Next, the support body was placed on the first member EL1 and pressed against the second member EL2. The support body was further compressed from 10 mm to 3 mm in thickness and secured in place with clips. The first member EL1 and the second member EL2 were made of SS400 material, each measuring 100 mm (length) × 25 mm (width) in plan view and 3.2 mm thick. 3 mm-thick spacers SP were placed on both sides of the support body to prevent it from becoming thinner than 3 mm. After a predetermined curing period, the tensile shear bond strength was measured. The details of the test procedure are as follows: Test conditions: Compliant with JIS K 6850 Adherend (first member EL1 and second member EL2): Oxide film (black scale or mill scale) is removed in advance by sandblasting. Curing period: 2 weeks at 23°C and 50% RH Adhesive area: 25mm (length) x 25mm (width) x 3mm (thickness) Test speed: 2.5mm / min. Destruction status: Visually confirmed [Industrial Applicability]

[0049] The adhesive sheet and adhesive method of the present invention can be used in production facilities such as factories, as well as in any other building such as warehouses and gymnasiums. [Explanation of symbols]

[0050] 100 Adhesive sheet of the present invention 110 1st surface material 111 void 120 Second surface material 130 Intermediates 131 Connecting thread EL1 First member EL2 Second member SP spacer

Claims

1. An adhesive sheet that holds a curable composition and can adhesively fix an adherend, comprising: a first surface material having a plurality of voids formed therein; a second surface material having a plurality of voids formed therein; an intermediate formed between the first surface material and the second surface material and capable of holding the curable composition impregnated therein; The first surface material, the second surface material, and the intermediate body are formed as a three-dimensional knitted structure or a three-dimensional net structure, the time required for the sheet to return to its original state after being bent in half while holding the curable composition having a viscosity of 25 Pa s is 3 seconds or less; An adhesive sheet characterized by:

2. The adherend is a steel material including H-shaped steel and angle steel, 2. The adhesive sheet according to claim 1.

3. the curable composition is any one of an acrylic adhesive, an epoxy adhesive, a modified silicone adhesive, a silicone adhesive, a urethane adhesive, and a polyester adhesive; 3. The adhesive sheet according to claim 1 or 2.

4. The curable composition is any one of a one-component heat-curing epoxy adhesive, a one-component moisture-curing acrylic-modified silicone adhesive, a one-component moisture-curing modified silicone adhesive, a one-component moisture-curing silicone adhesive, a two-component mixture moisture-curing epoxy-modified silicone adhesive, a two-component mixture curing epoxy adhesive, a two-component mixture fast-curing acrylic adhesive, a two-component mixture slow-curing acrylic adhesive, and a one-component moisture-curing urethane adhesive.

3. The adhesive sheet according to claim 1 or 2.

5. The three-dimensional knitted structure is configured such that the first surface material and the second surface material are connected by a connecting yarn, The first surface material, the second surface material, and the connecting yarn are each formed of either a synthetic monofilament yarn or a synthetic multifilament yarn.

4. The adhesive sheet according to claim 1.

6. A method for adhering and fixing an adherend using the adhesive sheet according to claim 1, comprising: an adhesive sheet testing step in which a test specimen of the adhesive sheet is tested to determine whether the test specimen is suitable or unsuitable as the adhesive sheet; a curable composition impregnation step of forming the test specimen determined to be suitable in the adhesive sheet testing step into an adhesive sheet and impregnating the adhesive sheet with the curable composition; an adhesive sheet placement step of placing the adhesive sheet holding the curable composition on the surface of the adherend, In the adhesive sheet testing step, the test piece having a planar dimension of 5 cm x 5 cm is folded in half while holding the curable composition having a viscosity of 25 Pa s, and if the restoration time required for the test piece to return to its original state is 3 seconds or less, the adhesive sheet is judged to be acceptable, and if the restoration time exceeds 3 seconds, the adhesive sheet is judged to be unacceptable. A bonding method characterized by:

7. The adherend is a steel material including H-shaped steel and angle steel, 7. The bonding method according to claim 6.

8. In the curable composition impregnation step, the adhesive sheet is impregnated with any one of an acrylic adhesive, an epoxy adhesive, a modified silicone adhesive, a silicone adhesive, a urethane adhesive, and a polyester adhesive.

8. The bonding method according to claim 6 or 7.

9. In the curable composition impregnation step, the adhesive sheet is impregnated with any one of a one-component heat-curing epoxy adhesive, a one-component moisture-curing acrylic-modified silicone adhesive, a one-component moisture-curing modified silicone adhesive, a one-component moisture-curing silicone adhesive, a two-component mixture moisture-curing epoxy-modified silicone adhesive, a two-component mixture curing epoxy adhesive, a two-component mixture fast-curing acrylic adhesive, a two-component mixture slow-curing acrylic adhesive, or a one-component moisture-curing urethane adhesive.

8. The bonding method according to claim 6 or 7.

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