JP6767148B2 - Crack growth suppression resin composition and crack growth suppression method - Google Patents

Description

The present invention relates to a crack growth suppressing resin composition and a crack growth suppressing method using the same.
More specifically, the present invention relates to a crack growth suppressing resin composition for suppressing the growth of cracks generated in a steel structure or the like, and a crack growth suppressing method using the same.

In recent years, there have been concerns about the progress of aging of infrastructure development such as buildings that were built during the period of high economic growth in Japan and more than 50 years have passed since the construction. However, many of these buildings are responsible for Japan's infrastructure, and in many cases it is not possible to easily rebuild or demolish them, or to stop the infrastructure functions for full-scale repair and reinforcement work. For these buildings, it is required to provide materials that enable simple repair and reinforcement work and exhibit sufficient functions. Usually, repair methods using cement, repairs using resin compositions, and even work sites are required. Materials such as fiber-reinforced prepregs that can be attached in the field have been proposed and are beginning to be used.

Repair work using cement is mainly being studied in civil engineering and construction using concrete. However, since cement has a problem of adhesiveness to the base, when applying vertically or when applying to the ceiling, it is necessary to separately install accessories such as reinforcing bars and wire mesh to make the cement adhere. It is necessary and has a problem that the construction becomes complicated (for example, Non-Patent Document 1).
Therefore, in vertical coating and coating on the ceiling, a coating type material that is lightweight and has excellent adhesiveness is desired because it does not drip or peel off due to its own weight.

To solve these problems, a construction method has been developed in which a resin is directly injected into a cracked portion to close the crack (for example, Patent Document 1 and Non-Patent Document 2). However, in order to allow the resin to penetrate into the fine cracks between the voids, a high-pressure injection method is required at the work site, and the viscosity of the resin used must be extremely low to make the resin flow well. , Filler cannot be added to the resin itself or strengthening measures cannot be taken, and reinforcement and strengthening cannot be obtained simply by filling the crack holes. Therefore, if a larger force is applied after the repair, the injected resin itself may break and cause new cracks. Further, this repair method mainly targets concrete, and is not necessarily a preferable method for repairing steel structures and the like.

Further, in order to overcome the above problems, a repair method has recently been developed in which a fiber-reinforced prepreg is attached to the surface of a building structure to maintain rigidity (for example, Non-Patent Document 3). This method is an application of a construction method (for example, Non-Patent Document 4) developed for the purpose of suppressing and preventing crack growth that has occurred in the tail wing of an aircraft, etc., in the field of construction and civil engineering, and is used as a structural member to be repaired. By designing from the tensile elastic modulus value of the fiber-reinforced prepreg to be attached, it is possible to easily obtain the effect of suppressing the growth of cracks generated in the structural member or the like (for example, Non-Patent Document 5).

However, unlike the tail of an aircraft, the structure of a building is not always flat, but there are irregularities and ribs, so the fiber-reinforced prepreg pasting method for pasting large sheets at work sites is not always necessary. It may not be preferable and improvement is required.

Patent Document 2 attempts to overcome the above-mentioned problems by processing and attaching a fiber-reinforced prepreg sheet according to the shape of a steel structure and the state of generated cracks. However, detailed work at the work site is not always a preferable measure in terms of high cost and safety.

In addition, in these construction methods, it is necessary to use a preferable adhesive when attaching the fiber-reinforced prepreg to the base, and depending on the selection of this adhesive, the fiber-reinforced prepreg will be peeled off after the application, which is sufficient. There is a problem that the effect of suppressing crack growth cannot be obtained.

In Patent Document 3 and Patent Document 4, in order to solve such a problem, the crack growth is suppressed by infiltrating the filler inside the crack by adding the nanofiller to the resin. Similar to Documents 2 and 3, it is not sufficient to verify the use of high-pressure infiltration equipment at work sites and the extent to which nanofillers permeate into cracks to obtain a crack suppressing effect.

In Patent Document 5, in order to overcome the advantages and problems of the proposed materials so far, by adjusting the polymer cement ratio, the thickness is such that the rigidity of the steel structure and the mortar layer with respect to the shear force becomes almost equal. We are proposing mold repair materials.

However, although the method of Patent Document 5 can obtain rigidity, since it uses a brittle material called cement, for example, in a building such as a steel bridge that is constantly exposed to vibrations, the strength of the spraying material itself and the blowing material itself It has elements that are not always sufficient in terms of adhesive strength between the attachment material and the structure to be steel that requires reinforcement.

Further, in Patent Documents 6 and 7, in order to overcome the advantages and problems of the proposed materials so far, a composite material system in which a fibrous filler is added to a thermosetting resin is used for building outer walls, building foundations, etc. We are proposing a simple method for reinforcement by coating. However, in this method, depending on the orientation of the fibrous filler, significant strength and elastic modulus deflection may occur, and not only may it not always be possible to obtain well-balanced reinforcement for the target building. Since the glass fiber and rock wool fiber proposed by this method are inorganic fillers, they have a high specific gravity. For example, when coating with a thickness perpendicular to the outer wall, they may hang down due to their own weight. Problems in terms of workability are likely to occur, and there is a problem that is not always sufficient.

As described above, there are research cases in which for fatigue cracks generated in steel building structures, etc., the growth of cracks is temporarily suppressed by coating resin compositions or cement-based materials, or by attaching reinforcing materials. However, there have been no cases in which a practical method of significantly suppressing and improving crack growth was achieved by a simple construction method that reduces the work load during construction.

Japanese Unexamined Patent Publication No. 2004-263048 Japanese Unexamined Patent Publication No. 2006-57352 Japanese Unexamined Patent Publication No. 2011-62809 Japanese Unexamined Patent Publication No. 2005-28462 Japanese Unexamined Patent Publication No. 2012-184575 Japanese Unexamined Patent Publication No. 2003-213136 Japanese Unexamined Patent Publication No. 2003-213938

Fukuda et al., Tunnel Engineering Report, Vol. 15, p29 (2006). Nittetsu Sumikin Cement Co., Ltd., Special Product Guide, June 2013. Ishikawa, Journal of the Japanese Society of Adhesion, 45, p139 (2009). M. Sato et al. , Adv. Comp. Mater. , 11 (1), p51-59 (2002). Matsumoto et al., Structural Engineering Papers, VOL. 59A, p798 (2013).

An object of the present invention is to provide a coating type repair material that realizes a simple construction method and mechanical properties that cannot be realized by conventional cement, polymer cement, resin composition or fiber reinforced prepreg. Here, the coating means applying the repair material at various work sites.
More specifically, the object of the present invention is to enable a repair and reinforcement method that is simple and has a small work load during construction, in order to suppress the growth of cracks generated in steel materials such as aged steel building structures. The present invention provides a crack growth suppressing resin composition and a crack growth suppressing method using the same.

As a result of diligent studies to improve the above problems, the inventor of the present invention mixes a room temperature curable thermosetting resin with a fibrous filler and a non-spherical filler selected in an appropriate filler shape in an appropriate blending ratio. However, by setting the tensile elasticity of the cured resin composition and the shear strength between the cured resin composition and the general structural steel material to a specific strength or higher, curing adhesion by vertical coating is possible. We have realized a crack growth suppressing resin composition that enables excellent crack growth suppression.
That is, the inventor of the present invention is a resin composition containing a room temperature curable thermosetting resin and a filler, and the resin composition contains both a fibrous filler and a non-spherical particle filler as the filler. The resin composition contained is a pre-curing viscosity of 5 to 2000 Pa · s at 25 ° C., and a fibrous filler and a non-spherical particle filler are formulated with respect to 100 parts by weight of a room temperature curable thermosetting resin. I)
Blending amount of non-spherical particle filler / blending amount of fibrous filler = 1 to 10 ... Formula (I)
20 to 150 parts by weight in total, and the average particle size of the non-spherical particle filler is 1 to 80 μm. Crack growth to reinforce the steel structure by applying and hardening to the cracked part of the steel structure. The present invention has been completed by using the inhibitory resin composition.

The invention of the present application exists in the following (1) to (10).
(1) A resin composition containing a room temperature curable thermosetting resin and a filler.
The resin composition contains both a fibrous filler and a non-spherical particle filler as the filler.
The resin composition has a viscosity of 5 to 2000 Pa · s at 25 ° C., and a fibrous filler and a non-spherical particle filler are mixed with 100 parts by weight of a room temperature curable thermosetting resin according to the formula (I).
Blending amount of non-spherical particle filler / blending amount of fibrous filler = 1 to 10 ... Formula (I)
Contains a total of 20 to 150 parts by weight in the compounding ratio of
A crack growth suppressing resin composition that reinforces the steel structure by applying and curing the non-spherical particle filler to the cracked portion of the steel structure having an average particle diameter of 1 to 80 μm.
(2) The crack growth suppressing resin composition according to (1) above, which is a resin composition having a viscosity of 50 to 2000 Pa · s at 25 ° C.
(3) The crack growth suppressing resin composition according to (1) or (2) above, wherein the fibrous filler is a carbon short fiber and / or a glass short fiber having a fiber length of 3 mm or more.
(4) The above-mentioned (1) to (3), wherein the non-spherical particle filler comprises one or more fillers selected from the group consisting of crushed pitch coke, talc, mica and clay. Crack growth suppressing resin composition.
(5) The crack growth suppressing resin composition according to any one of (1) to (4) above, wherein the non-spherical particle filler is a pulverized pitch coke product having coal-based acicular crystals.

(6) The crack growth suppressing resin composition according to any one of (1) to (5) above, wherein the room temperature curable thermosetting resin is a two-component mixed type epoxy resin that can be cured at room temperature.
(7) The crack growth suppressing resin composition according to any one of (1) to (6) above, which further contains a silane coupling agent.
(8) The crack growth suppressing resin composition according to any one of (1) to (7) above, which covers all or part of the cracks and hardens to a thickness of 1 mm or more on the surface of the steel having cracks. ..
(9) The crack growth suppressing resin composition according to any one of (1) to (8) above is applied to the crack portion of the steel structure with a thickness of 1 mm or more to prevent the crack growth of the steel structure. Rhagades growth suppression method.
(10) The method for suppressing crack growth according to (9) above, wherein a primer is applied to the contact surface between the crack growth resin composition and the steel structure, and then the crack growth suppression resin composition is applied.

According to the crack growth suppressing resin composition of the present invention, it is possible to suppress crack growth for fatigue cracks generated in a steel building structure by a simple method with less work load during construction.
The crack growth suppressing resin composition of the present invention is applied to a steel surface having cracks to cover a part or all of the cracks to a certain thickness, and by hardening, the resin composition adheres to the cracks and the cracks of the steel material grow. It produces a force that suppresses doing.
The crack growth suppressing resin composition of the present invention is a resin composition having the same composition, and by changing the thickness and shape of coating and serving on the steel material, the cross-sectional area and the adhesive area of the portion for reinforcing the steel material are changed. be able to. Therefore, resin compositions having the same composition can generate a force that opposes the force of crack growth of different steel materials.

It is a figure which shows the test piece coated with the crack growth suppressing resin composition which evaluated the crack growth suppressing effect. A coating of SS400 steel with a width of L mm, a length of H mm, and a thickness of t mm, in which a crack with a length of l mm was generated, was reinforced with a width of L mm, a length of 2 × hmm, and a thickness of 2 × tmm. It is a construction restoration model.

[Crack growth suppressing resin composition]
The crack growth suppressing resin composition of the present invention is used to reinforce a steel structure having cracks by applying it to a cracked portion of the steel structure and curing it.
The crack growth suppressing resin composition of the present invention contains a room temperature curable thermosetting resin, a fibrous filler, and a non-spherical particle filler. As will be described later, the blending ratio of the fibrous filler and the non-spherical particle filler is within a predetermined value range.
The crack growth suppressing resin composition of the present invention has a viscosity of 5 to 2000 Pa · s at 25 ° C. at room temperature before curing. The crack growth suppressing resin composition of the present invention is preferably in a state of a viscosity of 50 to 2000 Pa · s at 25 ° C. When the viscosity of the crack growth suppressing resin composition of the present invention is within the above range, the resin composition can be appropriately changed in shape and at the same time lose its shape when applied at the time of coating. Since it takes a certain amount of time, molding becomes easy.
Further, the resin composition may have a viscosity higher than 2000 Pa · s, have no fluidity, and the viscosity cannot be measured, as long as the gist of the present invention is not deviated.
The crack growth suppressing resin composition of the present invention may have a viscosity of 5 to 2000 Pa · s at 25 ° C. by thickening before curing.

[Room temperature curable thermosetting resin]
As the room temperature curable thermosetting resin according to the crack growth suppressing resin composition of the present invention, a thermosetting resin capable of room temperature curing is used. Examples of the thermosetting resin include epoxy resin, polyurethane resin, acrylic resin, polyester resin and the like.
The thermosetting resin is not particularly limited as long as it satisfies the conditions such as adhesiveness to the coated surface and strength of the cured product.
As the thermosetting resin, an epoxy resin is preferably used from the viewpoint of adhesiveness to a coated surface which is a steel material and strength of a cured product.
The epoxy resin is liquid, and a compound having two or more epoxy groups in one molecule is preferable. The epoxy resin includes, for example, a glycidyl ether type epoxy resin obtained from a polyol, a glycidyl amine type epoxy resin obtained from an amine having a plurality of active hydrogens, a glycidyl ester type epoxy resin obtained from a polycarboxylic acid, and a plurality of glycidyl ester type epoxy resins in the molecule. Polyepoxydo obtained by oxidizing a compound having a double bond is used. Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, bisphenol S type epoxy resins and other bisphenol type epoxy resins, epoxy resins having a biphenyl skeleton, and epoxy resins having a naphthalene skeleton. , Epoxy resin having a dicyclopentadiene skeleton, phenol novolac type epoxy resin, novolac type epoxy resin such as cresol novolac type epoxy resin, triglycidyl-p-aminophenol, N, N, N', N'-tetraglycidyl-4 , 4'-Glysidylamine type epoxy resin such as methylenedianiline, resorcindiglycidyl ether, triglycidyl isocyanurate, etc. can be mentioned, but in terms of performance and economy, bisphenol A type, bisphenol F type, bisphenol AD type, etc. A bifunctional or higher liquid epoxy resin such as a cresol novolac type glycidyl ether type epoxy resin is preferable.
The crack growth suppressing resin composition of the present invention is, for example, a two-component type in which a curing agent is mixed with an epoxy resin before construction, and immediately after mixing the main agent and the curing agent, the viscosity is 5 to 2000 Pa · s at 25 ° C. is there. At this time, the viscosity of the thermosetting resin as the main agent is preferably in the range of 0.5 to 30 Pa · s at 25 ° C., and more preferably 0.7 to 20 Pa · s. If the viscosity is 0.5 Pa · s or less, there are problems that the crack growth suppressing resin composition tends to drip during coating and that the required strength cannot be obtained. Further, if the viscosity is 30 Pa · s or more, it becomes difficult to knead the filler, and the viscosity of the crack growth suppressing resin composition is too high, which causes a problem that coating cannot be performed.
The viscosity of the crack growth suppressing resin composition according to the embodiment of the present invention can be measured according to the viscosity test method of JIS K 7233 epoxy resin and curing agent.

When the crack growth suppressing resin composition of the present invention is used by mixing a main agent and a curing agent, the curing agent used in the present invention is an acid anhydride type, an amine type, etc. as long as it can be cured at room temperature. Although not particularly limited, an amine-based curing agent is preferable in consideration of the pot life at the work site, the usage environment, and the like.
Examples of the amine-based curing agent include aliphatic polyamines such as diethylenetriamine, alicyclic polyamines such as isophoronediamine, aromatic amines such as diaminodiphenolsulphon, and modified products thereof.
As the amine-based curing agent, a liquid aliphatic polyamine having a viscosity in the range of 0.01 to 2 Pa · s and a modified product thereof can be cured at room temperature for a short time and can be easily mixed at the time of implementation. , Can be preferably used. The compounding ratio of the curing agent is not particularly limited, but those having an amine value such that the ratio of the curing agent is 20 to 100 parts with respect to 100 parts equivalent of the epoxy resin as the main agent are preferable.

In order to obtain a tensile elastic modulus that is a coating type and sufficient to suppress crack growth, the present inventor has formulated a fibrous filler and a non-spherical particle filler that are optimal for a thermosetting resin that is cured at room temperature. Found the ratio. Since the blending ratio of these fillers increases the viscosity of the obtained resin composition, not only the effect of strengthening the resin composition after blending can be obtained, but also there are advantages in terms of construction such as prevention of sagging during coating. It is also possible to obtain.

[Fibrous filler]
As the fibrous filler according to the present invention, inorganic fibers such as carbon fibers, glass fibers and rock wool fibers, and organic fibers composed of polymers can be used, and mixtures thereof can also be used. Among them, carbon fiber and glass fiber, or a mixture thereof, are more preferable in terms of handling during production.
Further, the fibrous filler according to the present invention is more preferably a chopped strand of carbon fiber or glass fiber having a length of 3 mm or more and a fiber diameter of less than 30 μm per fiber in terms of the development of tensile elastic modulus. Fiber can be used. Although the fibrous filler according to the present invention is not limited, the surface of the fibrous filler is surface-treated to improve the affinity with the matrix material, for example, a sizing treatment by epoxy resin sizing or the like, a silane coupling agent or the like. It is preferable that the surface is treated with.

[Non-spherical particle filler]
As the non-spherical particle filler according to the present invention, crushed pitch coke, talc, mica, clay, calcium carbonate, carbon black, crushed graphite, wallastnite, crushed silica powder, resin-based fine particles and the like can be used. A mixture of can also be used.
Among them, as the non-spherical particle filler according to the present invention, the non-spherical particle filler such as pitch coke crushed product, talc, mica and the like has a scaly particle shape, and is therefore required for the crack growth suppressing resin composition of the present invention. It is preferable because it easily develops the tensile elastic modulus. The non-spherical particle filler according to the present invention is more preferably a pitch coke pulverized product having a scaly shape, a high elastic modulus of its own, and excellent compatibility with a resin composition composed of carbon-based elements. is there.
In particular, the pitch coke crushed product having acicular crystalline material made from coal-based tar has high strength and elastic modulus of the crushed particles, and most of the composition is carbon, so that it is different from the case of other inorganic fillers. Unlike the non-spherical particle filler according to the present invention, it is the most preferable non-spherical particle filler because it can exhibit strength and elastic modulus without using a compatibilizer or the like and easily becomes scaly when pulverized. ..

The non-spherical particle filler used in the crack growth suppressing resin composition of the present invention has an average particle diameter of 1 to 80 μm, preferably 1 to 50 μm, more preferably 1 to 30 μm, and even more preferably an average. The particle size is 5 to 20 μm.
A non-spherical filler having an average particle size of less than 1 μm is not preferable because it makes coating difficult because it significantly increases the viscosity when mixed with a thermosetting resin mixture. Further, a non-spherical filler having an average particle diameter of more than 80 μm is not preferable because the strength of the thermosetting resin mixture cannot be obtained.
The average particle size of the non-spherical particle filler in the present invention is the median diameter (D ₅₀ ) of the non-spherical particle filler measured by a laser diffraction / scattering type particle size distribution measuring device.

[Filler content]
In the crack growth suppressing resin composition of the present invention, a total of 20 to 150 parts by weight, preferably 40 to 120 parts by weight of the fibrous filler and the non-spherical particle filler is added to 100 parts by weight of the room temperature fast-curing thermosetting resin. Partially mixed. If the blending amount of the fibrous filler and the non-spherical particle filler is less than 20 parts by weight with respect to 100 parts of the thermosetting resin that cures at room temperature, the tensile elastic modulus for obtaining the reinforcing effect cannot be obtained, and conversely. If the blending amount is more than 150 parts by weight, the number of voids generated in the resin composition increases, so that the strength of the crack growth suppressing resin composition itself is lowered.

Further, in the crack growth suppressing resin composition of the present invention, the blending ratio of the fibrous filler and the non-spherical particle filler blended in the room temperature curable thermosetting resin is more preferably 1 to 10 according to the following formula (I). Should be 2-8. If the compounding ratio is less than 1, a sufficient tensile elastic modulus for obtaining the reinforcing effect cannot be obtained, and if it exceeds 10, not only a sufficient tensile elastic modulus for obtaining the reinforcing effect but also a tensile strength cannot be obtained. It ends up.
Blending amount of non-spherical particle filler / blending amount of fibrous filler ... Formula (I)

In the present invention, the blending ratio of the thermosetting resin and the fibrous filler and / or the non-spherical particle filler is 3 to 30 parts by weight of the fibrous filler and 3 to 30 parts by weight of the non-spherical particle filler with respect to 100 parts of the thermosetting resin. The amount is preferably 10 to 120 parts by weight, more preferably 5 to 20 parts by weight of the fibrous filler, and 20 to 100 parts by weight of the non-spherical particle filler.
If the blending amount of the fibrous filler and the non-spherical particle filler is within the range of the present invention, there will be no problem in construction or mechanical properties such as elastic modulus and strength obtained, but the blending ratio should be designed. It is possible to further enhance the effect of suppressing crack growth.

[Crack growth suppressing resin composition]
As one of the embodiments according to the present invention, by mixing a chopped type fibrous filler and a non-spherical particle filler with a thermosetting resin that can be cured at room temperature, it is easy to do on-site without using an adhesive or the like. We have realized a crack growth suppressing resin composition that enables coating on vertical portions and can exhibit a tensile elastic modulus that suppresses the growth of cracks generated in a steel structure.
Hereinafter, the embodiment will be specifically described.

Further, in the present invention, as long as the physical properties of the crack growth suppressing resin composition are not impaired, a thermosetting resin other than the thermosetting resin used for the matrix resin, an inorganic filler, and an organic filler are mixed in combination, and further, dispersibility and adhesion are achieved. Additives such as a silane coupling agent, an ultraviolet inhibitor, a thermal deterioration inhibitor, an antioxidant, and a flow conditioner for improving the properties may be mixed in combination.

The crack growth suppressing resin composition of the present invention may be a two-component resin composition in which a thermosetting resin (main agent) and a curing agent are separately provided and the operator mixes both immediately before the work. By using the two-component type, a highly reactive curing agent can be used, which enables short-time construction on site, and since the main agent and curing agent are stored separately, there are no particular restrictions on storage conditions. It can be stored for a long period of time and can be installed promptly as needed.

〔Production method〕
Although not limited to the present invention, in the production of the crack growth suppressing resin composition of the present invention, it is preferable to use a mixer such as a general helical mixer, Henschel mixer, Dalton type mixer, or centrifugal mixer. It is more preferable to reduce the pressure in these mixings because the bubbles contained in the mixture can be removed.

Further, although not limiting the present invention, in the crack growth suppressing resin composition of the present invention, the resin and the curing agent should be mixed immediately before the coating work because of the ease of coating workability at the outdoor construction site. Is preferable. For example, in the crack growth suppressing resin composition of the present invention, a mixture of a base resin varnish or a curing agent mixed with fibrous and particulate fillers in advance is prepared, and the required amount of the base resin varnish is added to the mixture immediately before the coating operation. Alternatively, it is preferable to add and mix a curing agent. At that time, the mixture prepared in advance may be a mixture of the main agent, the fibrous filler and the particulate filler, one of which is mixed, and the curing agent to be used is mixed with the other filler. It may be a method of doing.
Considering the convenience at the time of construction, it is preferable to prepare a mixed varnish in which the main resin varnish, the fibrous filler and the particulate filler are mixed, and mix the curing agent immediately before the coating work.
On the other hand, a method of preparing a mixed varnish in which a curing agent, a fibrous filler and a non-spherical particle filler are mixed and mixing the main resin varnish immediately before the coating work is also preferably used, but the main mixture has a high viscosity. The method of adding the one having a lower viscosity is more preferable because it has better handleability in terms of implementation work.
The mixing method at the construction site is not particularly limited, but a method of mixing with a drum can-mounted mixer or a handy type mixer is preferable from the viewpoint of simplicity and less work load during construction. An example of a drum-mounted mixer is Maazel made by Seiken, and an example of a handy type mixer is a handy type Maazel made by Otsuka Brush.

The crack growth suppressing resin composition of the present invention is not limited, but the mixture of the main resin varnish and the curing agent has a viscosity of 5 to 2000 Pa · s at 25 ° C., more preferably 25. It is preferable that the temperature is 50 to 2000 Pa · s in order to simplify coating on walls, ceilings and the like. Therefore, in terms of preventing dripping during coating and handling, the viscosity immediately after mixing is preferably 10 to 2000 Pa · s at 25 ° C., more preferably 30 to 1500 Pa · s, and 50 to 1000 Pa · s. -S is even more preferable.
Further, as long as the gist of the present invention is not deviated, the mixture may have a viscosity higher than 2000 Pa · s, have no fluidity, and the viscosity cannot be measured.
The crack growth suppressing resin composition of the present invention may have thixotropy (sway denaturation) due to the nature of being a resin composition containing a thermosetting resin and a filler.
Although the crack growth suppressing resin composition of the present invention is not limited, the thixotropic index of medium-viscosity thixotropy (sway modification) in the standard JIS A 6024: 2008 of epoxy resin resin for building repair is 5 ± 1. Therefore, the crack growth suppressing resin composition of the present invention may exhibit a thixotropic index of 4 or more, preferably 5 or more in the measurement according to the same standard. When the thixotropic index is in the above range, the crack growth suppressing resin composition of the present invention does not easily lose its shape when applied at the time of coating, and coating / molding becomes easy.
Further, the curing time of the crack growth suppressing resin composition of the present invention is preferably about 10 minutes to 5 hours, more preferably about 30 minutes to 3 hours in terms of construction work. In addition, as an easy method for confirming a good cured state, the mixture immediately after mixing the main resin varnish and the curing agent is applied to a thickness of 20 mm with respect to the horizontal plane, and then the change in thickness 2 hours later is 2 mm. It is preferable that it is cured within.

Although the crack growth suppressing resin composition of the present invention is not limited, the crack growth suppressing resin composition of the present invention has, for example, a tensile shear strength of 1 MPa or more indicating adhesiveness to a general structural material rolled steel SS400. Is preferable. Even if the tensile shear strength is less than this, it does not cause a particularly significant hindrance, but it may be better in terms of long-term durability that peeling after coating is less likely to occur.
[Coating method]
The coating method of the crack growth suppressing resin composition of the present invention is not particularly limited as long as it can coat a material having a viscosity of 5 to 2000 Pa · s at 25 ° C., and a generally used method can be used. Can be used.
The crack growth suppressing resin composition of the present invention produces a crack growth suppressing effect by covering the cracks or applying the resin composition across the cracks to the cracked portions of the steel structure and hardening the cracks.
The thickness to be applied is not particularly limited as long as it can be applied and sufficient strength is maintained after curing. By applying the crack growth suppressing resin composition of the present invention to a crack portion of a steel structure with a thickness of 1 mm or more, preferably 20 mm or more, the effect of suppressing crack growth of the steel structure is high.
Further, the thickness of the crack growth suppressing resin composition of the present invention is changed according to the steel material of the steel structure, and the cross-sectional area and shape of the cured resin composition and the area of the adhesive surface are changed. It is possible to suppress crack growth of steel materials of different shapes and types.
The crack growth suppressing resin composition of the present invention is applied on the steel surface of a steel structure having cracks so as to cover all or part of the cracks and cure with a thickness of 1 mm or more. By coating in this way, the crack growth suppressing resin composition of the present invention can generate a stress for resisting the force of crack growth, and produces a crack growth suppressing effect.
As the curing method, normal temperature curing is possible, but a generally used method such as heating as needed can be used.

When applying the repair material, a primer may be used separately in order to improve the adhesion. The type of primer is appropriately selected depending on the material of the steel structure to be repaired and the resin type of the repair material. For example, an epoxy resin-based primer or a silane coupling agent-based primer is preferable.

Hereinafter, the crack growth suppressing resin composition according to the examples of the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

Measurement of mechanical properties (tensile bending, tensile elastic modulus) The tensile bending strength and tensile elastic modulus of the crack growth suppressing resin composition according to the embodiment of the present invention shall be in accordance with the JIS K 7162 / 1B plastic tensile property test method. I went.

Measurement of Shear Adhesive Strength The evaluation measurement of the adhesive strength based on the tensile shear strength between the crack growth suppressing resin composition and the general structural rolling steel material SS400 according to the embodiment of the present invention is the measurement of JIS K 6850 adhesive-rigid adherend. The tensile shear adhesive strength test method was followed.

Evaluation of crack growth suppressing effect Reinforcement of width L mm, length 2 x hmm, thickness 2 x tmm for SS400 steel material with width L mm, length H mm, and thickness t mm in which a crack with a length of l mm occurred at the center. A coated restoration model is prepared (Fig. 1), and simulations and measurements are performed using the measured values of tensile strength, tensile elastic modulus, and shear strength of each material, and the following conditions 1 to 3 are satisfied. Has a crack growth suppressing effect. Practically, if the following conditions 1 to 3 are satisfied, the growth of cracks generated in the steel structure can be suppressed.
(Condition 1)
With reference to References 1 and 2 below, the calculated value of Equation 1 falls within the range of 0.5 to 3.
(Equation 1)
[(L-l) x SS400 tensile elastic modulus x t]
/ [L x tensile modulus of coating material x 2t]
(Condition 2)
The internal stress (= "tensile elastic modulus" x 0.001) generated in the coating material when the deformation strain is 0.1% is equal to or less than the tensile strength of the coating material.
(Condition 3)
The adhesive strength at the interface between the coating material and the steel material is equal to or greater than the internal stress (= "tensile elastic modulus" x 0.001) generated in the coating material when the deformation strain is 0.1%.
Reference 1 "Bounded repair of aircraft strokes", edited by A. et al. A. Baker and R. Jones (Engineering application of fraction mechanicals, 7) M.D. Nijoff, Distributors for the United States and Canada, Krower Academic, 1988
Reference 2 M. Sato et al. , Adv. Comp. Mater. , Vol. 11, No. 1, p51-59 (2022).

Evaluation of workability of the coated product after coating The crack growth suppressing resin composition is applied to the center of the SS400 steel plate that is erected vertically, and the amount of downward sagging of the coated product after 24 hours is measured. Evaluation was performed by actual measurement.
The h, which is a reference for the length of the reinforcing coating, was measured using, for example, 100 mm.

Particle size measurement of non-spherical particle filler The particle size of the non-spherical particle filler according to the present invention is measured by measuring the volume-based particle size with a laser diffraction type particle size distribution meter (Microtrac MT3300EX manufactured by Nikkiso Co., Ltd.). D50) was determined as the average particle size.

[Examples 1 to 5, Comparative Examples 1 to 4]
Epoxy resin YD-128 (bisphenol A type liquid epoxy resin, viscosity 12 Pa · s) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and FXD821-F (modified alicyclic polyamine hardener, viscosity 0.065 Pa · s) manufactured by T & K TOKA Co., Ltd. Carbon fiber 80NT manufactured by Nippon Graphite Fiber Co., Ltd. (fiber lengths 6 mm and 25 mm) or glass fiber EC13- manufactured by OCV Tsu Co., Ltd. as a fibrous filler with respect to the resin composition obtained by mixing s) at a ratio of 100:45. Table 1 shows pitch coke powder A (average particle diameter 15 μm) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. or talc K-1 (average particle diameter 8 μm) manufactured by Nippon Steel Co., Ltd. using 3MM995 (fiber length 3 mm) as a non-spherical particle filler. And, according to the formulation shown in Table 2, they were blended under normal temperature conditions using a rotation / revolution type mixer manufactured by Shinky Co., Ltd. to produce coating type crack growth suppressing resin compositions A to I. The strength and elastic modulus of the manufactured coating mold crack growth suppressing resin compositions A to I are measured by tensile tests, and the shear adhesive strength using the rolled steel material SS400 for general structure and the post-coating coated product are obtained. The workability of the above was evaluated.
The test piece for the tensile test is prepared by cutting the crack growth suppressing resin compositions A to I from the cured flat plate by stretching the crack growth suppressing resin compositions A to I on a flat plate and leaving it as it is at room temperature overnight. In order to eliminate the influence of residual stress and the like and perform a physical property test, the cured flat plate was left as it was under normal temperature conditions for about overnight to perform leveling.
On the other hand, the shear adhesive strength measurement test piece is a general structural rolled steel material SS400 (width 32 mm × length 100 mm × thickness) coated with crack growth suppressing resin compositions A to I with a thickness of 0.75 mm and a length of 50 mm. A test piece was prepared by stacking two 3 mm) sheets to bond them and leaving them to stand overnight at room temperature in the same manner as a flat plate for a tensile test. Table 1 shows the evaluation results of Examples, and Table 2 shows the evaluation results of Comparative Examples.
Regarding the crack growth suppressing effect of the resin compositions A to I, the resin composition after curing from simulation and measurement has a tensile strength of 30 MPa or more, a tensile elastic modulus of 5 GPa or more, and a shear bond strength of 1 MPa or more. When satisfied, the crack growth suppressing effect: Yes (○), and when any of these values was not satisfied, the crack growth suppressing effect: No (×).
Regarding the workability of the coated product after coating, the crack growth suppressing resin compositions A to I were placed in the center of the SS400 steel piece having a width of 10 mm and a length of 500 mm in the vertical length direction of 100 mm and a coating thickness of 20 mm. If the amount of sagging of the coated material within 24 hours after coating was within 20 mm, it was evaluated as ◯, and if it was 20 mm or more, it was evaluated as ×.

比較例５では混合物の粘度が高すぎ、試験片を作製できなかった。
比較例６では容易に破断してしまい、弾性率の測定ができなかった。 [Example 6, Comparative Examples 5 to 6]
For 100 parts by weight of the resin composition obtained by mixing the epoxy resin YD-128 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and the curing agent FXD821-F manufactured by T & K TOKA Co., Ltd. at a ratio of 100:45, carbon fiber 80NT manufactured by Nippon Graphite Fiber Co., Ltd. ( Using pitch coke powders A to C manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. with a fiber length of 6 mm), coating-type crack growth-suppressing resin compositions J to L were produced by a mixer according to the formulation shown in Table 3, and examples were obtained. The respective strengths, elastic ratios and shear bond strengths were evaluated in the same manner as in 1 to 5 and Comparative Examples 1 to 4. The pitch coke powders A to C manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. are pitch coke powders adjusted to three types of particle size by fine grinding in order to confirm the effect of the particle size, and the average of massive pitch cokes. Pitch coke powder A was finely pulverized to a particle size of 15 μm, and fine powder having a maximum particle size of less than 1 μm recovered as dust during fine pulverization was limited to pitch coke powder B and coarsely pulverized (average particle size about 500 μm). It was designated as pitch coke powder C. Further, the crack growth suppressing effect of the crack growth suppressing resin compositions J to L and the workability of the coated product after coating were evaluated in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 4. .. Table 3 shows the evaluation results of Examples and Comparative Examples.

In Comparative Example 5, the viscosity of the mixture was too high to prepare a test piece.
In Comparative Example 6, it broke easily and the elastic modulus could not be measured.

[Example 7]
The crack growth suppressing resin composition of Example 4 was applied to the test piece in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6, except that the test piece was coated with an epoxy resin primer. The status of implementation workability was evaluated. Table 4 shows the evaluation results.

[Example 8]
Example 1 except that 1 part by weight of a glycidyl-based silane coupling agent A-187 manufactured by Momentive Performance Materials was added to 100 parts by weight of the resin composition to the crack growth suppressing resin composition of Example 4. In the same manner as in Comparative Examples 1 to 6, the shear adhesive strength and the workability of the coated product after coating were evaluated. Table 4 shows the evaluation results.

From the results shown in Tables 1 to 4, the crack growth suppressing resin composition of the present invention has good workability and a crack growth suppressing effect, but the resin composition of the comparative example is used for the coating product. In addition to having some problem in sex, the effect of suppressing crack growth has not been obtained. From this, the effect of the present invention is clear.

The present invention can be used in the field of construction / construction such as repair of steel building structures.

Claims (7)

A resin composition containing a room temperature curable thermosetting resin and a filler.
The resin composition, as the filler, contain both fiber length 3mm or more short carbon fibers and lepidolite flake filler,
The resin composition has a viscosity of 50 to 2000 Pa · s at 25 ° C., and a carbon short fiber and a scaly filler are mixed with 100 parts by weight of a room temperature curable thermosetting resin according to the formula (I).
Blending amount of scaly filler / blending amount of short carbon fibers = 1-10 ... Formula (I)
Contains a total of 20 to 150 parts by weight in the compounding ratio of
A crack growth suppressing resin composition for reinforcing a steel structure by applying the scaly filler to a cracked portion of the steel structure and curing the scaly filler having an average particle size of 1 to 80 μm. Scaly filler, pitch coke crushed ore, talc, and crack growth inhibiting resin composition according to claim 1 consisting of one or more fillers selected from the My mosquito or Ranaru group. The crack growth suppressing resin composition according to claim 1 or 2 , wherein the scaly filler is a pulverized pitch coke product having coal-based acicular crystals. The crack growth suppressing resin composition according to any one of claims 1 to 3 , wherein the room temperature curable thermosetting resin is a two-component mixed type epoxy resin that can be cured at room temperature. The crack growth suppressing resin composition according to any one of claims 1 to 4 , further containing a silane coupling agent. The crack growth suppressing resin composition according to any one of claims 1 to 5 , wherein all or part of the cracks are covered and cured to a thickness of 1 mm or more on the surface of the steel having cracks. A method for suppressing crack growth in which the crack growth suppressing resin composition according to any one of claims 1 to 6 is applied to a crack portion of a steel structure to a thickness of 1 mm or more to suppress crack growth in the steel structure. ..

Images