JP2021066770A - Displacement detection sheet and laminate - Google Patents

Abstract

To provide a displacement detection sheet capable of satisfactorily detecting local displacement of an inspection object, and a laminate having the displacement detection sheet.SOLUTION: A displacement detection sheet is provided that is composed of a prepreg sheet obtained by impregnating a fiber base material with a liquid composition including the following (a) to (d), and provides a molded article obtained by curing the prepreg sheet and having a tensile modulus of elasticity of 1,000 MPa or more and 2,000 MPa or less. (a) one or more curable resins selected from the group consisting of a vinyl ester resin, an unsaturated polyester resin, an acrylic resin and an urethane resin. (b) monomer. (c) photopolymerization initiator. (d) thickening material of 1 mass% or more and 50 mass% or less based (a)+(b)+(c) 100 of mass%, the thickening material being non-crosslinked acrylic resin powder.SELECTED DRAWING: None

Description

The present invention relates to a displacement detection sheet and a laminate.

Conventionally, in order to ensure the safety of concrete buildings and metal structures, a method of detecting local displacements such as cracks and joint deviations that occur in buildings and structures has been known.

For example, in piping equipment installed in a factory, the connection points between pipes may gradually loosen due to expansion and contraction due to vibration or temperature change. Therefore, it is confirmed by daily inspection work that there is no local displacement at the joint of the pipes.

In addition, concrete structures used in many infrastructure buildings such as bridges and tunnels may crack when exposed to wind and rain. If the cracks are left unattended, the cracks may grow, causing a decrease in the strength of the entire structure and a peeling of a part of the structure. Therefore, in order to properly maintain and manage the concrete structure, it is required to appropriately repair the cracks generated in the concrete structure.

Regarding the cracks generated in such a concrete structure, for example, a concrete microcrack sensor used for monitoring the minute cracks generated in the concrete structure is known (see, for example, Patent Document 1).

The concrete microcrack sensor described in Patent Document 1 has a laminated structure of a fiber-containing plastic plate and an adhesive. The concrete microcrack sensor is used by tilting the fiber direction of the sheet-like fiber of the fiber-containing plastic plate at a predetermined angle with respect to the direction in which the crack spreads. As a result, when tensile stress due to cracks is applied to the concrete microcrack sensor, the fiber-containing plastic plate is whitened along the fiber direction of the sheet-like fibers, and crack growth can be detected.

Japanese Patent No. 5567057

The concrete microcrack sensor described in Patent Document 1 needs to be attached while checking the fiber direction so that the fiber direction of the sheet-shaped fiber is at a predetermined angle with respect to the direction in which the crack spreads. Therefore, the work efficiency at the time of construction tends to decrease.

Further, the concrete micro-crack sensor needs to have a predetermined angle between the fiber direction and the crack direction, and its use is limited only to the detection of cracks in concrete whose displacement direction can be specified. Therefore, when there are multiple displacement directions, such as a displacement in which the pipes are relatively separated from each other in the axial direction of the pipe, or a displacement in which the pipes are gradually twisted around the axis of the pipe, such as a loosening of a connection point in a piping facility. Cannot adapt.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a displacement detection sheet capable of satisfactorily detecting a local displacement of a subject. Another object of the present invention is to provide a laminated body having such a displacement detection sheet.

In order to solve the above problems, the present invention includes the following aspects.

[1] Displacement detection in which the liquid composition containing the following (a) to (d) comprises a prepreg sheet impregnated in a fiber base material, and the tensile elastic modulus of the molded product obtained by curing the prepreg sheet is 1000 MPa or more and 2000 MPa or less. Sheet.
(A) One or more curable resin selected from the group consisting of vinyl ester resin, unsaturated polyester resin, acrylic resin, and urethane resin (b) Monomer (c) Photopolymerization initiator (d) Uncrosslinked acrylic resin powder A certain thickener: 1% by mass or more and 50% by mass or less when (a) + (b) + (c) is 100% by mass.

[2] The displacement detection sheet according to [1], which is cured by absorbing light in a wavelength band of 365 nm or more and 410 nm or less.

[3] A laminate having the displacement detection sheet according to [1] or [2] and a pair of protective films covering both sides of the displacement detection sheet.

[4] The laminate according to [3], wherein at least one of the pair of protective films transmits light in a wavelength band that cures the displacement detection sheet.

[5] The laminate according to [4], further comprising a light-shielding film that covers the protective film that transmits light in the wavelength band and does not transmit light in the wavelength band among the pair of protective films.

According to the present invention, it is possible to provide a displacement detection sheet capable of satisfactorily detecting a local displacement of a subject. Further, it is possible to provide a laminated body having such a displacement detection sheet.

FIG. 1 is a cross-sectional view showing a displacement detection sheet according to an embodiment of the present invention and a laminated body having the displacement detection sheet. FIG. 2 is a process diagram showing a method of manufacturing the displacement detection sheet of the present embodiment.

The displacement detection sheet according to the present embodiment is a prepreg sheet in which a fiber base material is impregnated with a liquid composition containing the following (a) to (d). The displacement detection sheet is preferably one obtained by impregnating a fiber base material with a liquid composition and then heat-treating the liquid composition to thicken it.
(A) One or more curable resin selected from the group consisting of vinyl ester resin, unsaturated polyester resin, acrylic resin, and urethane resin (b) Monomer (c) Photopolymerization initiator (d) Uncrosslinked acrylic resin powder A certain thickener: 1% by mass or more and 50% by mass or less when (a) + (b) + (c) is 100% by mass.

Further, in the displacement detection sheet of the present embodiment, the tensile elastic modulus of the molded product after being completely cured is 1000 MPa or more and 2000 MPa or less.

Further, the laminate according to the embodiment of the present invention has the above-mentioned displacement detection sheet and a pair of protective films covering both sides of the displacement detection sheet.

When such a displacement detection sheet is attached to a subject and cured, and then a local displacement occurs in the subject, the molded body after the displacement detection sheet is cured according to the displacement turns white. .. Therefore, the local displacement of the subject can be visualized and easily detected.

Examples of the subject for detecting the local displacement include a cracked concrete structure. When the displacement detection sheet is attached to such a concrete structure over the cracks and cured, the concrete structure is locally displaced around the cracks as the cracks grow, and the cured product becomes white. And local displacement can be detected.

Moreover, the seam of the piping structure can be mentioned as a subject. When the displacement detection sheet is attached and cured across the flanges that connect the pipes to each other, the cured product is whitened due to the displacement that the connection points between the pipes are loosened or twisted, and the local displacement can be detected.
Hereinafter, they will be described in order.

[Displacement detection sheet, laminate]
FIG. 1 is a cross-sectional view showing a displacement detection sheet according to an embodiment of the present invention and a laminated body having the displacement detection sheet. As shown in the figure, the laminated body 1 has a displacement detection sheet 2 of the present embodiment and protective films 3 and 4 which are a pair of protective films covering both sides of the displacement detection sheet 2.

((A) Curable resin)
The displacement detection sheet 2 contains a curable resin as a main component. As the curable resin, vinyl ester resin, unsaturated polyester resin, acrylic resin, and urethane resin can be used. These may be used alone or in combination of two or more.

Examples of the vinyl ester resin include a reaction product of an epoxy resin and an unsaturated monobasic acid such as acrylic acid and methacrylic acid. Examples of the epoxy resin contained in the vinyl ester resin include a bisphenol type epoxy resin, a phenol novolac type epoxy resin, and a cresol novolac type epoxy resin. Examples of the bisphenol type epoxy resin include bisphenol A type, bisphenol AD type, bisphenol S type, and bisphenol F type.

Examples of the unsaturated polyester resin include a reactant obtained by a condensation reaction between a polyhydric alcohol and an unsaturated polybasic acid (and, if necessary, a saturated polybasic acid).

The curable resin used is preferably one in which the raw material monomer does not contain styrene. The curable resin that does not use styrene as a raw material does not contain unreacted styrene, and styrene is less likely to be released from the obtained prepreg sheet (displacement detection sheet). Therefore, the displacement detection sheet 2 can be easily used indoors.

((B) Monomer)
The displacement detection sheet 2 contains a monomer. The monomer functions as a solvent for dissolving the curable resin (a) and adjusting the viscosity. Further, if (b) the monomer is multifunctional, it also functions as a cross-linking agent that polymerizes and cross-links the above-mentioned (a) curable resin.

The monomer in this embodiment preferably does not contain styrene. As a result, styrene is less likely to be released from the obtained prepreg sheet (displacement detection sheet). Therefore, the displacement detection sheet 2 can be easily used indoors.

As the monomer in the present embodiment, one or more selected from the group consisting of acrylic acid, methacrylic acid and esters thereof ((meth) acrylic acid ester) can be preferably used.

Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. , (Meta) cyclohexyl acrylate can be exemplified.

Further, as the (meth) acrylic acid ester, hydroxy group-containing monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate, ethylene glycol di (meth) acrylate and diethylene glycol (meth) Polyfunctional monomers such as acrylates, triethylene glycol di (meth) acrylates, butylene glycol di (meth) acrylates, trimethylolpropandi (meth) acrylates, and trimethylolpropantri (meth) acrylates can also be used.

The monomer (b) may be commercially available after being mixed with the curable resin (a) in advance, but even in such a form, it is suitable as a raw material for the displacement detection sheet 2 of the present embodiment. Can be used.

The ratio of the (b) monomer to the total amount of the (a) curable resin and the (b) monomer is preferably 20% by mass or more, and more preferably 30% by mass or more. Further, it is preferably 80% by mass or less, and more preferably 70% by mass or less. The upper and lower limits of the ratio of (b) monomer to (a) curable resin + (b) monomer can be arbitrarily combined.

((C) Photopolymerization Initiator)
The displacement detection sheet 2 contains a photopolymerization initiator. As the photopolymerization initiator, one capable of generating radicals by light irradiation and initiating radical polymerization is used.

As the photopolymerization initiator, known agents such as acetophenone-based, benzophenone-based, and acylphosphine oxide-based agents can be used. Specifically, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1-phenyl-2-hydroxy-3-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1 −Phenylpropane-1-one and the like can be mentioned. Only one kind of these polymerization initiators may be used, or two or more kinds thereof may be used in combination.

When the photopolymerization initiator is a solution dissolved in a solvent, it is preferable that the solvent does not contain styrene. As a result, styrene is less likely to be released from the obtained prepreg sheet (displacement detection sheet).

As the photopolymerization initiator, one having an absorption wavelength band of 365 nm or more and 410 nm or less and absorbing light in a wavelength band in this range to generate radicals can be preferably used. Since the light in such a wavelength band is deviated from the ultraviolet absorption region of the curable resin, the light energy required for the radical generation reaction of the photopolymerization initiator can be effectively absorbed.

Further, the absorption wavelength band of the photopolymerization initiator may not be included in the wavelength band of 365 nm or more and 410 nm or less. In that case, it is preferable to use a photosensitizer having an absorption wavelength band in combination with a wavelength band of 365 nm or more and 410 nm or less.

((D) thickener)
The displacement detection sheet 2 contains a thickener. The thickener is an uncrosslinked acrylic resin powder. The content of the thickener (d) in the liquid composition constituting the displacement detection sheet 2 is 1% by mass or more and 50% by mass when the above (a) + (b) + (c) is 100% by mass. It is as follows.

As the thickener in the present embodiment, a thickener having a viscosity of 40,000 mPa · s or more when measured under the following measurement conditions can be preferably used.
(Measurement condition)
90 g of a mixture of the following formulations (a1) to (c1) and (d) is heated to 85 ° C. and held at 85 ° C. using a Brookfield B-type viscometer (spindle: No. 7, rotation speed: 100 rpm). Measure the viscosity with.
(A1) Vinyl ester resin (bisphenol A type vinyl ester resin): 60 g
(B1) Monomer (methacrylic acid ester): 40 g ((a1) + (b1) = 100 g)
(C1) Photopolymerization Initiator (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide): 1 g
(D) Thickener, which is an uncrosslinked acrylic resin powder: 10.1 g

Under the above measurement conditions, the amount of "(d) thickener which is an uncrosslinked acrylic resin powder" is 10% by mass when (a1) + (b1) + (c1) is 100% by mass. Is.

As the methacrylic ester used as the "(b1) monomer", the same methacrylic ester exemplified as the "(b) monomer" described above can be used. As the methacrylic acid ester, a polyfunctional monomer can also be used.

A thickener having a viscosity of less than 40,000 mPa · s under the above measurement conditions tends to cause stringiness when the protective films 3 and 4 are peeled from the displacement detection sheet 2. On the other hand, the thickener having a viscosity of 40,000 mPa · s or more under the above measurement conditions can suppress the above-mentioned problems when the displacement detection sheet 2 is produced.

The thickener preferably has an average degree of polymerization of 10,000 or more. The average degree of polymerization of the thickener is preferably 50,000 or less.

If the average degree of polymerization of the thickener is less than 10,000, the viscosity when heat-treated and thickened is unlikely to increase, so that stringing is likely to occur when the protective films 3 and 4 are peeled from the displacement detection sheet 2. On the other hand, when the average degree of polymerization of the thickener is 10,000 or more, the viscosity when heat-treated and thickened can be increased to a desired value, and the above-mentioned problems can be suppressed.

The thickener used is preferably one that does not contain styrene as a raw material. The thickener that does not use styrene as a raw material does not contain unreacted styrene, and styrene is less likely to be released from the obtained prepreg sheet (displacement detection sheet). As the thickener, a polymer of acrylic acid or methacrylic acid or an ester thereof can be preferably used, and for example, a polymer of methyl methacrylate (MMA) can be preferably used.

The average degree of polymerization of the thickener can be appropriately adjusted by a commonly known method such as the polymerization temperature, the polymerization time, the amount of the polymerization initiator, and the rate of addition of the monomer into the polymerization system.

(Fiber base material)
The displacement detection sheet 2 has a fiber base material impregnated with a liquid composition containing the above-mentioned (a) curable resin, (b) monomer, (c) photopolymerization initiator, and (d) thickener.

Examples of the fibers (constituent fibers) constituting the fiber base material include inorganic fibers such as glass fibers, carbon fibers and ceramic fibers, and resin fibers such as aramid fibers, acrylic fibers, polyester fibers, polyethylene fibers and nylon fibers. .. Among them, glass fiber which is excellent in light transmission and strength and is also inexpensive can be preferably used. Only one type of these constituent fibers may be used, or two or more types may be used in combination.

The fiber base material may be a woven fabric (woven fabric), a knitted fabric, or a non-woven fabric. Among them, the fiber base material is preferably a non-woven fabric. Since the fiber direction of the non-woven fabric is less likely to be biased in a certain direction, it is not necessary to worry about the attachment direction of the displacement detection sheet 2 when the displacement detection sheet 2 is attached to the subject, and improvement in work efficiency can be expected. Further, since the non-woven fabric is easier to stretch than the woven fabric in which the fiber direction is fixed, it is preferable because it easily follows the local displacement of the subject.

As the fiber base material, those having a thickness of 0.01 mm or more and 10 mm or less can be preferably used.

In the displacement detection sheet 2 of the present embodiment, when the total amount of (a) curable resin and (b) monomer is 100 parts by mass, (c) the content of the photopolymerization initiator is 0.01 part by mass or more. It is preferably 0.1 part by mass or more, and more preferably 0.1 part by mass or more. Further, (c) the content of the photopolymerization initiator is preferably 5 parts by mass or less, and more preferably 1 part by mass or less. The upper limit value and the lower limit value of the content (number of copies) of these (c) photopolymerization initiators can be arbitrarily combined.

Similarly, when the total amount of (a) curable resin, (b) monomer and (c) photopolymerization initiator is 100 parts by mass, the content of (d) thickener is 1 part by mass or more. Is preferable, and 5 parts by mass or more is more preferable. Further, (d) the content of the thickener is preferably 50 parts by mass or less, and more preferably 30 parts by mass or less. The upper limit value and the lower limit value of the content (number of copies) of these (d) thickeners can be arbitrarily combined.

Further, a thickener after thickening a liquid composition containing (a) a curable resin, (b) a monomer, (c) a photopolymerization initiator, and (d) a thickener with respect to the entire displacement detection sheet 2. The ratio can be considered to be the same as the ratio of the liquid composition to the total amount of the liquid composition and the fiber substrate.

The ratio of the fiber base material to the total amount of the liquid composition and the fiber base material is preferably 3% by mass or more, and more preferably 5% by mass or more. Further, it is preferably 80% by mass or less, and more preferably 50% by mass or less. The upper and lower limits of the ratio of the liquid composition to the total amount of the liquid composition and the fiber base material can be arbitrarily combined.

The displacement detection sheet 2 may contain other components such as pigments and fillers as long as the effects of the present invention are not impaired.

The displacement detection sheet 2 of the present embodiment has a tensile elastic modulus of 1000 MPa or more and 2000 MPa or less after being completely cured.

In the present invention, "complete curing" refers to the normal use of the displacement detection sheet 2 by reacting the curable resin and the monomer contained in the displacement detection sheet 2 with the photopolymerization initiator when the displacement detection sheet 2 is used. Indicates that it is cured to the degree of polymerization in the application.

Specifically, the displacement detection sheet 2 of the present embodiment is pulled by the method specified in JIS K7164 "Plastic-Test method for tensile properties-Part 4: Test of isotropic and orthogonal anisotropic fiber reinforced plastic". The tensile elastic modulus obtained by conducting the test is 1000 MPa or more and 2000 MPa or less.

The test piece used for the tensile test is a type 1B system A type test piece according to the above JIS standard.
The measurement was performed on three test pieces, and the arithmetic mean value of the obtained measurement results at the three points was adopted as the tensile elastic modulus.

If the tensile elastic modulus is less than 1000 MPa, the molded product after curing will stretch too much, and it will be difficult to confirm discoloration of the molded product. On the other hand, when the tensile elastic modulus is 1000 MPa or more, it becomes easy to confirm the discoloration of the whitened portion when the molded product after curing is deformed by tension.

If the tensile elastic modulus exceeds 2000 MPa, the molded product after curing is difficult to stretch and easily breaks due to tensile stress, so that it is difficult to confirm discoloration of the molded product. On the other hand, when the tensile elastic modulus is 2000 MPa or less, the molded product after curing is less likely to be broken by tension, and discoloration of the whitened portion can be easily confirmed.

The tensile elastic modulus is preferably 1100 MPa or more, more preferably 1200 MPa or more. The tensile disconnection rate is preferably 1900 MPa or less, more preferably 1800 MPa or less.
The upper limit value and the lower limit value of the tensile elastic modulus can be arbitrarily combined.

The tensile elastic modulus can be controlled by adjusting the amount of any of the above-mentioned (a) curable resin and (b) monomer.

For example, in the case of (a) curable resin, the tensile elastic modulus tends to decrease when the amount of urethane acrylate (Yupika 8965 (manufactured by Japan U-Pica Co., Ltd.)) is increased. On the contrary, when the amount of urethane acrylate is reduced, the tensile elastic modulus tends to increase.

Further, in the case of the monomer (b), when the amount of methoxypolyethylene glycol # 400 acrylate (AM-90G (manufactured by Shin-Nakamura Kogyo Co., Ltd.)) is increased, the tensile elastic modulus tends to decrease. On the contrary, when the amount of methoxypolyethylene glycol # 400 acrylate is reduced, the tensile elastic modulus tends to increase.

In addition, when the material of the fiber base material is changed from the inorganic fiber to the resin fiber, the tensile elastic modulus tends to decrease.

(Protective film)
The protective films 3 and 4 are films that protect the surface of the displacement detection sheet 2 during storage of the displacement detection sheet 2.

As the protective films 3 and 4, polyester films such as polyethylene terephthalate (PET) films, nylon films, vinylon films, polycarbonate films, polyethylene films, polypropylene films, polyvinyl chloride films and the like can be used.

If styrene is not used as the raw material contained in the displacement detection sheet 2, or if styrene is not contained, even a film made of a resin that swells due to styrene can be suitably used as the protective films 3 and 4. it can.

The protective films 3 and 4 may have a strip-like shape extending in one direction, or the strip-shaped protective film may be cut into a predetermined size according to the form of the product.

At least one of the protective films 3 and 4 is capable of transmitting light in the absorption wavelength band of the photopolymerizable initiator or photosensitizer contained in the displacement detection sheet 2 with respect to light in the absorption wavelength band. It is preferably substantially transparent. As a result, when the displacement detection sheet 2 is irradiated with light to be cured, at least one of the pair of protective films can be left attached to the displacement detection sheet 2 for repair using the displacement detection sheet 2. Work becomes easy.

As described above, when the protective films 3 and 4 are substantially transparent to light in the absorption wavelength band of the photopolymerizable initiator or photosensitizer, the laminate 1 is transparent. A light-shielding film that covers 4 and does not transmit light in the wavelength band may be provided. By having such a light-shielding film, the displacement detection sheet 2 can be light-shielded during storage. Therefore, the displacement detection sheet 2 can be well stored without being cured.

[Manufacturing method of displacement detection sheet]
FIG. 2 is a process diagram showing a method of manufacturing the displacement detection sheet of the present embodiment.
First, as shown in FIG. 2A, the above-mentioned liquid composition (represented by reference numeral 21) is applied onto the protective film 3.

Examples of the method of applying the liquid composition 21 on the protective film 3 include a die coating method, a roller coating method, a spray coating method, a curtain coating method, a slot coating method, a comma coating method, a gravure coating method, and a reverse coating method. The bar coating method and the screen printing method can be mentioned. In FIG. 2A, the liquid composition 21 is applied from the die 100.

Next, as shown in FIG. 2B, the fiber base material 22 is overlaid on the coating film of the liquid composition 21 coated on the protective film 3, and the fiber base material 22 is impregnated with the liquid composition 21.

Next, as shown in FIG. 2C, the protective film 4 is superposed on the fiber base material 22, and then heat-treated to thicken the liquid composition 21.

In the present invention, the "heat treatment" is intended to increase the viscosity of the liquid composition 21. The heat treatment may be performed using a heating device such as a heater, or may be performed by irradiating infrared rays. In the figure, it is shown as irradiating infrared IR.

The temperature of the heat treatment is, for example, 30 ° C. or higher and 180 ° C. or lower. The heat treatment temperature is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. The heat treatment temperature is preferably 160 ° C. or lower, more preferably 140 ° C. or lower. The upper limit value and the lower limit value of the temperature of these heat treatments can be arbitrarily combined.
The heat treatment time is, for example, 60 minutes or less.
The temperature and time of these heat treatments are appropriately set according to the configuration of the manufacturing apparatus to be used, the product standard of the displacement detection sheet 2, and the like.

In the method for producing a displacement detection sheet of the present embodiment, the liquid composition 21 contains the thickener which is the above-mentioned (d) uncrosslinked acrylic resin powder. The thickener has a viscosity of 40,000 mPa · s or more within 20 minutes of holding time when measured under the following measurement conditions.
(Measurement condition)
90 g of a mixture of the following formulations (a1) to (c1) and (d) is heated to 85 ° C. and held at 85 ° C. using a Brookfield B-type viscometer (spindle: No. 7, rotation speed: 100 rpm). Measure the viscosity with.
(A1) Vinyl ester resin (bisphenol A type vinyl ester resin): 60 g
(B1) Monomer (methacrylic acid ester): 40 g ((a1) + (b1) = 100 g)
(C1) Photopolymerization Initiator (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide): 1 g
(D) Thickener, which is an uncrosslinked acrylic resin powder: 10.1 g

Under the above measurement conditions, the thickener having a viscosity of 40,000 mPa · s within a holding time of 20 minutes can rapidly increase the viscosity to a desired value during heat treatment, and can suppress an increase in production time. it can. Further, a thickener having a viscosity of 40,000 mPa · s within a holding time of 10 minutes under the above measurement conditions is preferable because the production time can be further suppressed.

The thickener preferably has an average degree of polymerization of 10,000 or more and 50,000 or less. When the average degree of polymerization of the thickener is 10,000 or more, the viscosity can be preferably increased to a desired level during heat treatment. A thickener whose average degree of polymerization is not within the above range cannot be increased to a desired viscosity.
In this way, the displacement detection sheet 2 of the present embodiment can be manufactured.

As shown in FIG. 1, the displacement detection sheet of the present embodiment can be easily used by forming a laminated body 1 in which a pair of protective films are laminated on both sides. That is, after cutting the laminate 1 to a desired size, one of the protective films is peeled off, the displacement detection sheet 2 is attached to the repaired portion, and the displacement detection sheet 2 is irradiated with light to be cured. , Can be easily repaired. When the protective film has light transmission property, it is possible to irradiate the displacement detection sheet 2 with light through the protective film after the displacement detection sheet 2 is attached to the repaired portion, so that the work is easy. It becomes.

The displacement detection sheet and the laminated body of the present embodiment have the above-described configuration.

According to the displacement detection sheet having the above configuration, the local displacement of the subject can be satisfactorily detected.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. The various shapes and combinations of the constituent members shown in the above-mentioned examples are examples, and can be variously changed based on design requirements and the like within a range that does not deviate from the gist of the present invention.

For example, when the displacement detection sheet is attached to the subject, the displacement detection sheet may be attached directly to the subject, or may be attached via a known primer (adhesive).

[Example]
Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
A monomer (methacrylic acid ester) solution (60% by mass) of vinyl ester resin (bisphenol A type vinyl ester resin) and urethane acrylate (Yupika 8965 (manufactured by Japan U-Pica Co., Ltd.)) are mixed in a mass ratio of 95: 5. To obtain a raw material mixture.

Further, 1 g of a photopolymerization initiator (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide) was weighed and mixed with respect to 100 g of the obtained raw material mixture. To the obtained mixture, 10.1 g of thickener 1 (average degree of polymerization 20000, acrylic resin, uncrosslinked, core-shell structure), which is 10% by mass when the mixture is 100% by mass, is added. , A stirrer (Three-One Motor, manufactured by Shinto Kagaku Co., Ltd.) was used to stir at 300 rpm to 500 rpm for 10 minutes at room temperature to obtain a liquid composition.

The obtained liquid composition was impregnated into a non-woven fabric (polyester non-woven fabric, Sontara 8021, manufactured by DuPont Co., Ltd.) and then heated at 80 ° C. for 20 minutes to prepare a prepreg sheet (displacement detection sheet).

From the molded body obtained by irradiating the obtained displacement detection sheet with light and completely curing it, a type 1B system A type test piece specified in JIS K7164 was prepared. Using the obtained test piece, a tensile test specified in JIS K7164 was performed. The tensile test was performed three times, and the arithmetic mean value was calculated for each measured value.

(Examples 2 to 3 and Comparative Examples 1 to 7)
A displacement detection sheet was prepared in the same manner as in Example 1 except that the raw material mixture was adjusted at the ratio shown in Table 1. A tensile test was carried out on the molded body obtained by curing the displacement detection sheet in the same manner as in Example 1.

The evaluation results are shown in Table 1. In Table 1, "whitening" was evaluated as follows. Those with a bleaching evaluation of "○" were judged to be non-defective.
(Whitening evaluation criteria)
〇: Whitening could be confirmed by visual evaluation.
× 1: The test piece broke before the whitening was confirmed by visual evaluation.
× 2: Whitening could not be confirmed by visual evaluation.

A to C shown in Table 1 indicate the following materials, respectively.
A: Monomer (methacrylic acid ester) solution of vinyl ester resin (bisphenol A type vinyl ester resin) (60% by mass)
B: Urethane acrylate (Yupika 8965 (manufactured by Japan U-Pica Co., Ltd.))
C: Methoxypolyethylene glycol # 400 acrylate (AM-90G (manufactured by Shin-Nakamura Kogyo Co., Ltd.))

As a result of the evaluation, in the displacement detection sheets of Examples 1 to 3, it was confirmed that the stretched portion was satisfactorily whitened in response to a slight displacement, and it was expected that the local displacement could be detected.

On the other hand, in the displacement detection sheets of Comparative Examples 1, 3, 4, and 7, the test piece broke before confirming whitening.

Further, the displacement detection sheets of Comparative Examples 2, 5 and 6 were excessively stretched according to the stress as compared with the displacement detection sheets of Examples 1 to 3, and whitening could not be confirmed in the tensile test. Since the displacement detection sheets of Comparative Examples 2, 5 and 6 are easily stretched, even if the stretched parts are whitened as in the displacement detection sheets of Examples 1 to 3, the whitened parts are widely dispersed and whitened. Is considered to be difficult to visually confirm. Therefore, it was found that the displacement detection sheets of Comparative Examples 2, 5 and 6 are not suitable for the purpose of the present application of detecting local displacement.

From the above, it is considered that the displacement detection sheets of Comparative Examples 1 to 7 are not suitable for detecting local displacement because it is difficult to confirm whitening.

From the above results, the usefulness of the present invention could be confirmed.

1 ... Laminated body, 2 ... Displacement detection sheet, 3, 4 ... Protective film, 21 ... Liquid composition, 22 ... Fiber base material

Claims (5)

The liquid composition containing the following (a) to (d) comprises a prepreg sheet impregnated in a fiber base material.
A displacement detection sheet in which the tensile elastic modulus of a molded product obtained by curing the prepreg sheet is 1000 MPa or more and 2000 MPa or less.
(A) One or more curable resin selected from the group consisting of vinyl ester resin, unsaturated polyester resin, acrylic resin, and urethane resin (b) Monomer (c) Photopolymerization initiator (d) Uncrosslinked acrylic resin powder A certain thickener: 1% by mass or more and 50% by mass or less when (a) + (b) + (c) is 100% by mass. The displacement detection sheet according to claim 1, wherein the displacement detection sheet is cured by absorbing light in a wavelength band of 365 nm or more and 410 nm or less. The displacement detection sheet according to claim 1 or 2,
A laminate having a pair of protective films covering both sides of the displacement detection sheet. The laminate according to claim 3, wherein at least one of the pair of protective films transmits light in a wavelength band that cures the displacement detection sheet. The laminate according to claim 4, further comprising a light-shielding film that covers the protective film that transmits light in the wavelength band and does not transmit light in the wavelength band among the pair of protective films.

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