JP2018053601A - Multi-layer sheet for preventing concrete from falling off and method for manufacturing the same - Google Patents

Abstract

There is provided a multilayer sheet for preventing concrete peeling, which can observe cracks, cracks, etc. on the surface of the structure over time even after reinforcement of the concrete structure.
A multilayer sheet for preventing concrete peeling according to the present disclosure includes a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing substrate on the first (meth) acrylic pressure-sensitive adhesive layer, A second (meth) acrylic pressure sensitive adhesive layer on the reinforcing substrate, wherein the refractive index of the reinforcing substrate is about 1.40 to about 1.60, and the reinforcing substrate is the first and / or Impregnated with the adhesive of the second (meth) acrylic pressure-sensitive adhesive layer.
[Selection] Figure 1

Description

  The present disclosure relates to a multilayer sheet for preventing concrete peeling and a method for producing the same.

  Conventionally, in order to prevent the peeling of concrete pieces from concrete structures such as bridges, tunnels, and elevated roads, a method of applying a coating agent for preventing concrete peeling to the concrete structure surface has been used.

  Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-342538) discloses a concrete in which an undercoat resin is applied to the surface of a concrete structure, a fiber substrate is applied to the application surface, and an overcoat resin is applied to the surface of the fiber substrate. A method of repairing a structure, wherein the viscosity of the undercoat resin is from 4,000 mPa · s to 100,000 mPa · s, the thixotropic index is from 2.0 to 5.0, and the viscosity of the topcoat resin is 100 mPa · s. A method for repairing a concrete structure is described in which the above is less than 4,000 mPa · s and the thixotropic index is 1.0 or more and less than 2.0.

  In Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-027718), a protective layer and an adhesive coating layer composed of a reinforcing layer and / or a sticking layer are bonded to each other, and the adhesive coating layer is bonded to the concrete structure. It describes that a concrete structure repair / reinforcement / deterioration prevention sheet applied to a concrete structure having an adhesive layer made of an adhesive or a hot-melt adhesive is applied to the concrete structure.

JP 2006-342538 A JP 2004-027718 A

  Conventionally, construction has been performed to reinforce a concrete structure by applying a reinforcing fiber layer after applying an adhesive to the surface of the concrete structure. However, since such construction requires work processes and time, it takes time to inconvenience by blocking a part of the road during work, etc., and restrictions on time, cost, safety, etc. at places where construction can be performed It takes. Also, the finish depends on the construction skills of the workers. Even with such a reinforced concrete structure, cracks, cracks, and the like may occur, and there has been a demand for a simple reinforcing means that can observe the temporal change of the concrete structure surface even after reinforcement.

  The present disclosure provides a multilayer sheet for preventing concrete peeling that allows the surface of a structure to be observed over time even after reinforcement of the concrete structure and that can be easily applied in a short time.

  According to one embodiment of the present disclosure, a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing substrate on the first (meth) acrylic pressure-sensitive adhesive layer, and a reinforcing substrate And a second (meth) acrylic pressure-sensitive adhesive layer, the multilayer sheet for preventing concrete peeling, wherein the refractive index of the reinforcing base is about 1.40 to about 1.60. Is provided with an adhesive of the first and / or second (meth) acrylic pressure-sensitive adhesive layer.

  According to another embodiment of the present disclosure, a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing substrate on the first (meth) acrylic pressure-sensitive adhesive layer, and a reinforcing substrate And a second layer (meth) acrylic pressure-sensitive adhesive layer, wherein the reinforcing material has an opening length of about 4.0 mm or more and an opening area of about 40% or more. There is provided a multilayer sheet for preventing concrete from peeling off, which has transparency corresponding to the open area.

  According to another embodiment of the present disclosure, a step of providing a first (meth) acrylic pressure sensitive adhesive layer comprising an ultraviolet curable pressure sensitive adhesive, and a first (meth) acrylic pressure sensitive adhesive Providing a reinforced substrate having a refractive index of about 1.40 to about 1.60 on the agent layer, and a second (meth) acrylic system comprising an ultraviolet curable pressure-sensitive adhesive on the reinforced substrate Providing a pressure-sensitive adhesive layer and impregnating; and irradiating ultraviolet rays to cure the first and second (meth) acrylic pressure-sensitive adhesive layers simultaneously or separately; A method for producing a multilayer sheet for prevention is provided.

  Since the multilayer sheet for preventing concrete peeling of the present disclosure is wholly or partially transparent, cracks, cracks, etc. on the surface of the structure can be observed over time even after the concrete structure is reinforced.

  Since the multilayer sheet for preventing concrete peeling of the present disclosure can be directly applied to a concrete structure optionally having a surface treatment layer at a time, it is observed as compared with a conventional construction method that requires a coating means at the time of construction. Therefore, sufficient transparency can be easily expressed without requiring skill, and construction work can be completed in a short time.

  The above description should not be construed as disclosing all embodiments of the invention and all advantages related to the invention.

It is a perspective view of the multilayer sheet for concrete peeling prevention of one embodiment of this indication. It is sectional drawing of the concrete structure to which the multilayer sheet for concrete peeling prevention of FIG. 1 is applied. It is sectional drawing of the multilayer sheet for concrete peeling prevention in another embodiment of this indication. It is a side view of a punching test apparatus. It is a front view of a punching test apparatus. It is the upper side figure (right side) and A-A 'cross section (left side) of the punching test apparatus of another structure. It is a photograph of the multilayer sheet for concrete peeling prevention in the embodiment of Examples 1 and 2 of the present disclosure. It is a photograph of the multilayer sheet for concrete peeling prevention in the embodiment of comparative examples 1-3 of this indication. It is a photograph of the reinforcing substrate in Reference Examples 1 and 2 of the present disclosure. It is a photograph of the multilayer sheet for concrete peeling prevention in the embodiment of Examples 3 and 4 of this indication. It is a photograph of the multilayer sheet for concrete peeling prevention in the embodiment of comparative examples 4 and 5 of this indication. It is a simplified diagram illustrating the relationship between the opening length (OP) and the fiber diameter (D) in the reinforcing base material of the present disclosure. It is a photograph of the concrete structure reinforced with the conventional construction method (comparative example 6) and the multilayer sheet for concrete peeling prevention in the embodiment of Example 1.

  The multilayer sheet for preventing concrete peeling in the first embodiment includes a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing base on the first (meth) acrylic pressure-sensitive adhesive layer, and reinforcement. And a second (meth) acrylic pressure-sensitive adhesive layer on the substrate, the multilayer sheet for preventing concrete from peeling off, wherein the refractive index of the reinforcing substrate is about 1.40 to about 1.60. The reinforcing substrate is impregnated with the adhesive of the first and / or second (meth) acrylic pressure sensitive adhesive layer. Since this multilayer sheet for preventing concrete exfoliation is entirely transparent, changes in the appearance of the concrete structure surface can be observed over time. Compared with conventional construction methods that require application means at the time of construction, sufficient transparency (visibility) to observe can be expressed easily without requiring skill, and construction work can be completed in a short time Can do.

  The multilayer sheet for preventing concrete peeling in the second embodiment includes a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing base on the first (meth) acrylic pressure-sensitive adhesive layer, and reinforcement. And a second (meth) acrylic pressure-sensitive adhesive layer on the substrate, the multilayer sheet for preventing concrete peeling, wherein the reinforcing substrate has an opening length of about 4.0 mm or more and about 40% or more. It has an open area, and a portion corresponding to the open area has transparency. Since this concrete peeling prevention multilayer sheet is partially transparent, the appearance change of the concrete structure surface can be observed over time. Compared with conventional construction methods that require application means at the time of construction, sufficient transparency (visibility) for easy observation can be expressed easily without requiring skill, and construction work can be completed in a short time can do.

  In the multilayer sheet for preventing concrete exfoliation in the first or second embodiment, the reinforcing base material may include glass fiber or polymer monofilament. By including such a material in the reinforcing base material, it is possible to improve the transparency and the prevention of peeling off of the concrete.

In the multilayer sheet for preventing concrete from peeling off in the first embodiment, the reinforcing base material includes glass fibers, and the thickness and basis weight of the reinforcing base material are about 0.20 mm or less and about 40 to about 130 g / m ^2. May be. Such a reinforcing base material has sufficient resistance to peeling off of the concrete, and the pressure-sensitive adhesive can easily be impregnated into the reinforcing base material, can improve transparency, and can follow the concrete structure. Excellent pastability.

  In the multilayer sheet for preventing concrete from peeling off in the first embodiment, the reinforcing base material may include a polymer monofilament, and the thickness of the reinforcing base material may be about 0.40 mm or less. The reinforcing base material including the polymer monofilament is sufficiently provided with a concrete peeling prevention property, and the pressure-sensitive adhesive can easily be impregnated into the reinforcing base material, thereby improving the transparency. When the thickness of the reinforcing base material is about 0.40 mm or less, the followability to the concrete structure and the sticking property are also excellent.

  In the multilayer sheet for preventing concrete exfoliation in the first embodiment, the reinforcing base material may include glass fibers that have not been treated with a sealing agent and a sizing agent. When such a reinforcing substrate is used, the pressure-sensitive adhesive is easily impregnated into the reinforcing substrate, and the transparency of the multilayer sheet is improved.

  In the multilayer sheet for preventing concrete exfoliation in the first or second embodiment, the tensile strength and thickness of the reinforcing substrate may be about 200 N / 25 mm or more and about 0.05 mm or more. By using a reinforcing base material having a tensile strength of about 200 N / 25 mm or more, it is possible to improve the concrete preventive property. When the thickness of the reinforcing substrate is about 0.05 mm or more, vertical wrinkles due to MD-direction tension applied to the reinforcing substrate during the production of the multilayer sheet are less likely to occur, resulting in poor thickness and poor appearance of the multilayer sheet. Can be prevented.

  In the multilayer sheet for preventing concrete peeling in the first or second embodiment, a polymer layer containing a fluorine-based polymer or the like on the side opposite to the reinforcing substrate side of the first or second (meth) acrylic pressure-sensitive adhesive layer May be provided. By adopting such a polymer layer, it is possible to improve performance such as weather resistance.

  In the multilayer sheet for preventing concrete peeling in the first or second embodiment, the first and / or second (meth) acrylic pressure-sensitive adhesive layer may not contain a filler. When the pressure-sensitive adhesive layer does not contain a filler, it is possible to improve the impregnation property of the reinforcing substrate and the transparency of the multilayer sheet.

  The method for producing a multilayer sheet for preventing concrete peeling in the first or second embodiment includes a step of providing a first (meth) acrylic pressure-sensitive adhesive layer containing an ultraviolet curable pressure-sensitive adhesive; A step of providing a reinforcing substrate on the (meth) acrylic pressure-sensitive adhesive layer, and a second (meth) acrylic pressure-sensitive adhesive layer comprising an ultraviolet curable pressure-sensitive adhesive on the reinforcing substrate Optionally impregnating the pressure sensitive adhesive layer; optionally, providing a polymer layer on the second (meth) acrylic pressure sensitive adhesive layer; Curing the first and second (meth) acrylic pressure-sensitive adhesive layers simultaneously or separately. This production method can easily produce a multilayer sheet having sufficient transparency to observe the temporal change of the concrete structure surface.

  In the method for producing a multilayer sheet for preventing concrete peeling in the first or second embodiment, the viscosity of the partial polymer of the ultraviolet curable pressure-sensitive adhesive may be about 10,000 mPa · s or less. When the viscosity of the partial polymer of the UV-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is within this range, the pressure-sensitive adhesive is excellent in impregnation into the reinforcing substrate, and the resulting multilayer sheet is transparent. Can be improved.

  The construction method of the multilayer sheet for preventing concrete peeling in the first or second embodiment includes a step of directly applying the multilayer sheet to the concrete structure or a step of applying the multilayer sheet to the concrete structure through the surface treatment layer. . This construction method can be easily constructed in a short period of time without requiring skill in expressing transparency as compared with a conventional construction method that requires an application means at the time of construction.

  Hereinafter, the present invention will be described in more detail for the purpose of illustrating representative embodiments of the present invention, but the present invention is not limited to these embodiments.

  In the present disclosure, “transparent” or “partially transparent” means performance capable of visually recognizing a hairline crack of about 0.3 mm or less, about 0.2 mm or less, or about 0.1 mm or less in a concrete structure. To do. Alternatively, based on the light transmittance calculated from Equation 3 described later, “entirely transparent” means that the light transmittance of the concrete peeling prevention multilayer sheet is 65% or more, 75% or more, or 80% or more. "Partially transparent" may mean that the light transmittance of the concrete peeling prevention multilayer sheet is more than 65%, 70% or more, or 75% or more.

  In the present disclosure, “(meth) acryl” means acryl or methacryl, and “(meth) acrylate” means acrylate or methacrylate.

In the present disclosure, the “opening length” means, for example, in the case of a substantially square lattice-shaped reinforcing base as shown in FIG. 12, the distance between the ends of adjacent fibers, that is, a substantially square shape. It means one side “OP” in the opening. In view of the manufacturing process and isotropy of the reinforcing base material, it is considered that a substantially square shape is desirable as the shape of the opening. However, when the shape of the opening is other, the maximum diagonal length may be the opening length. The “opening region” means the ratio of the area of the opening to the entire area of the reinforcing substrate. For example, in a reinforcing substrate having a substantially square lattice-like opening as shown in FIG. When the thickness is “D”, the following expression (1) is satisfied. When the lattice-shaped opening is substantially rectangular, the following formula (2) is satisfied when the long side and the short side of the opening are “OP _length ” and “OP _short ”. Here, “substantially” means including variations caused by manufacturing errors and the like, and it is intended that a variation of about ± 20% is allowed.

  In the present disclosure, “impregnation” means a state in which a reinforcing substrate is immersed in and covered with a pressure-sensitive adhesive. When the reinforcing base is composed of monofilament, the periphery of the monofilament is covered with a pressure sensitive adhesive, and when the reinforcing base is composed of multifilament, it is between each fiber. Means that the periphery of the multifilament is covered while the pressure sensitive adhesive penetrates into a part of it (the pressure sensitive adhesive does not necessarily have to penetrate between all the fibers). In order to improve transparency, it is desirable to cover so as not to include bubbles (air).

  The multilayer sheet for preventing concrete peeling according to an embodiment of the present disclosure includes a first (meth) acrylic pressure-sensitive adhesive layer, a reinforcing base on the first (meth) acrylic pressure-sensitive adhesive layer, A second (meth) acrylic pressure sensitive adhesive layer on the reinforcing substrate, wherein the refractive index of the reinforcing substrate is about 1.40 to about 1.60, and the reinforcing substrate is the first and / or Or it is impregnated with the adhesive of the second (meth) acrylic pressure-sensitive adhesive layer.

  The concrete peeling prevention multilayer sheet of one embodiment of the present disclosure is shown in a perspective view in FIG. 1, and a concrete structure to which the concrete peeling prevention multilayer sheet is applied is shown in a sectional view in FIG. As shown in FIGS. 1 and 2, the multilayer sheet 1 for preventing concrete peeling includes a reinforcing base impregnated with a pressure-sensitive adhesive 2 constituting a first and / or second (meth) acrylic pressure-sensitive adhesive layer. A material 3 is provided.

The first and second (meth) acrylic pressure sensitive adhesive layers are tacky and may each be composed of the same component or different components, the monomer component comprising a monofunctional monomer and a polyfunctional methacrylate, A partial polymer obtained by partial polymerization can be contained. Here, “tackiness” is a storage elastic modulus (G ′) measured at 10 radians / second at an application temperature (which can be measured at 20 ° C. to 22 ° C.) is less than about 3 × 10 ⁵ Pascals. Means (Darquist standard).

((Meth) acrylic pressure sensitive adhesive)
In this embodiment, the (meth) acrylic pressure-sensitive adhesive contains a partial polymer obtained by partial polymerization of a monomer component containing a monofunctional monomer and a polyfunctional methacrylate.

  The monofunctional monomer includes an alkyl acrylate having an alkyl group having 1 to 18 carbon atoms (hereinafter sometimes referred to as “C1-18 alkyl acrylate”), and an unsaturated monomer having a vinylcarbonyl group and a polar group (hereinafter referred to as “C1-18 alkyl acrylate”). Sometimes referred to as "polar unsaturated monomer").

  The proportion of the C1-18 alkyl acrylate and the polar unsaturated monomer in the monofunctional monomer is such that the total amount of the monofunctional monomer is 100% by mass, and the C1-18 alkyl acrylate is about 70% by mass or more, about 85% by mass or more, About 87% by weight or more, about 99% by weight or less or about 98% by weight or less, and the polar unsaturated monomer is about 1% by weight or more, or about 2% by weight or more, about 30% by weight or less, about 15% by weight or less; It is preferably about 13% by mass or less. When the proportion of the C1-18 alkyl acrylate and the polar unsaturated monomer in the monofunctional monomer is within the above range, the followability, the adhesive force, and the holding force are excellent.

The alkyl acrylate having 1 to 18 carbon atoms in the alkyl group means that the alkyl alcohol has 1 to 18 carbon atoms when the alkyl acrylate is viewed as an ester of acrylic acid and alkyl alcohol. That is, when an alkyl acrylate ^{_{CH 2 = CH-COO-R}} 1 and, ^{R 1} is meant an alkyl group having 1 to 18 carbon atoms.

  The number of carbon atoms of the alkyl group of the alkyl acrylate is preferably 4 or more, and preferably 12 or less. When such an alkyl acrylate is included as a monofunctional monomer, the adhesive force (adhesive force) of the multilayer sheet is improved.

  As alkyl acrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl Acrylate, n-heptyl acrylate, n-octyl acrylate, isooctyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, n-undecyl acrylate, n-dodecyl acrylate, n-tridecyl acrylate, n-tetra Decyl acrylate, n-pentadecyl acrylate, n-hexadecyl acrylate, n-heptadecyl acrylate, n Octadecyl acrylate, and the like.

  Among these, in consideration of transparency, followability to irregularities and curved surfaces, adhesive force, holding power, etc., n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-Nonyl acrylate, isononyl acrylate, and n-decyl acrylate are preferable, and n-butyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate are more preferable.

  The polar unsaturated monomer has a vinylcarbonyl group and a polar group.

  Examples of the polar group include a hydroxyl group, a carboxyl group, a carbamoyl group, an amino group, an epoxy group, and a nitrile group, and among these, a hydroxyl group, a carboxyl group, and an amino group are preferable.

Vinyl carbonyl _{group, CH 2 = CH-C (} = O) - refers to a group represented by. The vinylcarbonyl group and the polar group may be directly bonded, or may be bonded via a linking group such as an alkylene group.

Examples of polar unsaturated monomers include:
Hydroxyl group-containing unsaturated monomers such as 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate;
Carboxyl group-containing unsaturated monomers such as acrylic acid;
Carbamoyl group-containing unsaturated monomers such as acrylamide;
Amino group-containing monomers such as N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate;
And epoxy group-containing unsaturated monomers such as glycidyl acrylate.

  Considering transparency, followability, adhesive strength, holding power, etc., among these, a hydroxyl group-containing unsaturated monomer, a carboxyl group-containing unsaturated monomer, and a carbamoyl group-containing unsaturated monomer are preferable, and a carboxyl group-containing unsaturated monomer and carbamoyl A group-containing unsaturated monomer is more preferable, and a carboxyl group-containing unsaturated monomer is more preferable. Specifically, 2-hydroxyethyl acrylate, acrylic acid, and acrylamide are preferable, acrylic acid and acrylamide are more preferable, and acrylic acid is more preferable.

The polyfunctional methacrylate is a compound having two or more groups represented by CH ₂ ═C (CH ₃ ) —C (═O) —.

  Polyfunctional methacrylates are 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, penta Examples include erythritol dimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexamethacrylate, trimethylolpropane trimethacrylate, and tetramethylolmethane trimethacrylate.

  Of these, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, ethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate are preferable in view of transparency, followability, adhesive strength, holding power, and the like.

  The content of the polyfunctional methacrylate in the monomer component is preferably about 0.05 mmol or more, or about 0.1 mmol or more and about 0.25 mmol or less with respect to 100 g of the monofunctional monomer. When the content ratio of the polyfunctional methacrylate is within the above range, the followability, adhesive force and holding force are excellent.

  The partial polymer is obtained by partial polymerization of a monomer component, and can also be referred to as a “partial polymer of monomer component”.

  Here, the partial polymer is a composition obtained by polymerizing at least a part of the monomer component, and an unreacted ethylenically unsaturated bond (C) derived from a monofunctional monomer or polyfunctional methacrylate in the composition. = C) is present.

  The viscosity of the partial polymer at 25 ° C. can be about 10,000 mPa · s or less, about 8000 mPa · s or less, or about 5000 mPa · s or less. The viscosity may be about 500 mPa · s or higher. When the viscosity range of the partial polymer is within the above range, since the impregnation property to the reinforcing base material can be improved and the coating can be applied with a thickness, a multilayer sheet excellent in transparency can be obtained, and the strength, followability, adhesion A multilayer sheet having excellent strength and holding power can be obtained. The viscosity defined here is a value measured using a B-type viscometer (BH type) manufactured by Tokyo Keiki Co., Ltd. (Minato-ku, Tokyo, Japan). It is carried out at 25 ° C. using a # 6 rotor (rotation speed: 20 rpm), and the value for 1 minute after the start of measurement is taken as the measurement value.

  The viscosity of the partial polymer varies depending on the degree of progress of the partial polymerization, and the viscosity of the partial polymer tends to increase as the partial polymerization proceeds. Therefore, the viscosity of the partial polymer can be easily adjusted to a desired range by appropriately adjusting the amount of the polymerization initiator used for the partial polymerization, the reaction time of the partial polymerization, and the like.

  It can also be said that the partial polymer contains an unreacted monomer component and a solid content that is a polymer of the monomer component. Here, the solid content in the partial polymer is about 1% by mass or more, about 2% by mass or more, about 10% by mass or less or about 10% by mass based on the total amount of the partial polymer in consideration of the impregnation property to the reinforcing substrate. It is preferable that it is 7 mass% or less.

  The amount of the solid content in the partial polymer can be determined by measuring the amount of the remaining solid content after removing the unreacted monomer component from the partial polymer. For example, the partial polymer can be obtained in an oven at 120 ° C. for 2 hours. The mass after drying can be taken as the solid content.

  The partial polymer can be obtained, for example, by blending a monomer component with a photopolymerization initiator and irradiating with light to photopolymerize the monomer component.

As a photopolymerization initiator, an azo compound such as azobisinbutyronitrile;
Benzoins such as benzoin, benzoin methyl ether, benzoisoethyl ether, benzoin propyl ether, benzoin isobutyl ether, α-methylbenzoin, α-phenylbenzoin;
Anthraquinones such as anthraquinone, methylanthraquinone and chloroanthraquinone;
and onium salts such as p-methoxybenzenediazonium, hexafluorophosphate, diphenyliodonium, triphenylsulfonium, and the like.

Examples of photopolymerization initiators include benzyldialkyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one;
1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl Α such as -1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, etc. -Hydroxyalkylphenones;
2-Methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2- (dimethyl Α-aminoalkylphenones such as amino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone;
Acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide;
Titanocenes such as bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium;
1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3 And oxime esters such as 1- (0-acetyloxime);

The light irradiation is preferably ultraviolet irradiation. For example, the monomer component formulated with photoinitiators, irradiation intensity of about 0.05 mW / cm ² or more, or about 0.1 mW / cm ² or more, about 10 mW / cm ² or less, or about 5 mW / cm ² or less, about the irradiation time A partial polymer can be obtained by irradiation with ultraviolet rays for 5 seconds or more, or about 10 seconds or more, about 300 seconds or less, or about 240 seconds or less.

  In the present embodiment, the (meth) acrylic pressure-sensitive adhesive may be one in which a polyfunctional methacrylate is further added in addition to the partial polymer. However, in this embodiment, the total amount of the polyfunctional methacrylate blended in the (meth) acrylic pressure-sensitive adhesive is about 0.05 mmol or more, or about 0.1 mmol or more, and about 0.0. It can be 25 mmol or less.

  Here, “the total amount of polyfunctional methacrylate blended in the (meth) acrylic pressure sensitive adhesive” means that the polyfunctional methacrylate used as a monomer component for obtaining the partial polymer and the acrylic polymer separately from the partial polymer The total amount of polyfunctional methacrylate added to the pressure-sensitive adhesive composition is shown.

  In this embodiment, the outstanding followability and holding | maintenance force can be made compatible by making the total amount of the polyfunctional methacrylate mix | blended with a (meth) acrylic-type pressure-sensitive adhesive into the said range.

  In this embodiment, the (meth) acrylic pressure sensitive adhesive may contain components other than the partial polymer.

The (meth) acrylic pressure-sensitive adhesive preferably contains a photopolymerization initiator because it facilitates formation of a pressure-sensitive adhesive layer by ultraviolet curing. Examples of the photopolymerization initiator include the same ones as described above. The ultraviolet curable pressure sensitive adhesive has the following advantages over other adhesives such as a thermosetting adhesive and a fast curable adhesive.
(1) Since the ultraviolet curable pressure-sensitive adhesive of the present disclosure does not need to contain a solvent, it is easy to increase the film thickness (for example, 0.3 mm or more) compared to a solvent-based adhesive or the like.
(2) The thermosetting adhesive takes time for thermal polymerization, and there is a risk of bubble formation of monomer during heating (defective appearance), but the ultraviolet curable pressure sensitive adhesive of the present disclosure reduces such risk. can do.
(3) Since it can be cured at a desired stage while taking into account the degree of impregnation of the adhesive into the reinforcing material, it is easy to ensure the desired transparency.

  The photopolymerization initiator contained in the (meth) acrylic pressure-sensitive adhesive may be an unreacted product of the photopolymerization initiator used in the production of the partial polymer described above. Although it may be added, the latter is more preferable in view of ease of adjusting the molecular weight of the pressure-sensitive adhesive, productivity, and the like.

  The content of the photopolymerization initiator in the (meth) acrylic pressure-sensitive adhesive is about 0.01 parts by mass or more, or about 0.05 parts by mass or more, and about 1.0 parts by mass with respect to 100 parts by mass of the partial polymer. Or about 0.5 parts by mass or less.

  The (meth) acrylic pressure-sensitive adhesive may further contain a polar unsaturated monomer or the like separately from the partial polymer. By containing these, the adhesive force of the (meth) acrylic pressure-sensitive adhesive can be adjusted. Here, examples of the polar unsaturated monomer are the same as described above.

  The (meth) acrylic pressure-sensitive adhesive preferably does not contain a filler in consideration of transparency and impregnation into a reinforcing substrate, but contains a filler as long as it does not cause a problem with transparency. May be. The content of the filler can be about 0.1% by volume or more and about 10% by volume or less based on the total solid content of the (meth) acrylic pressure-sensitive adhesive.

  The shape of the filler is not particularly limited, and a filler having a spherical shape, a plate shape, a flake shape, a needle shape, or the like can be used. Of these, spherical fillers are preferred in view of moldability into a multilayer sheet and impregnation into a reinforcing substrate. From the viewpoint of transparency, the average particle diameter of the filler is preferably about 100 μm or less.

  Examples of the filler include an inorganic filler made of an inorganic material selected from the group consisting of silica, titania, alumina, zirconia, vanadia, ceria, iron oxide, antimony oxide, tin oxide, aluminum / silica, and combinations thereof. Can be mentioned.

  The (meth) acrylic pressure-sensitive adhesive may contain additives other than those described above within a range that does not cause problems in transparency, curability and the like. Examples of the additive include a plasticizer, a tackifier, a pigment, a dye, a reinforcing agent, a reinforcing agent, a flame retardant, an antioxidant, an ultraviolet absorber, and a stabilizer.

  The (meth) acrylic pressure-sensitive adhesive is preferably subjected to defoaming treatment, for example, by a vacuum defoaming machine, before the curing. Thereby, the hardening inhibition of the (meth) acrylic-type pressure-sensitive adhesive by contact with air bubbles (air), the appearance defect, etc. can be suppressed.

  The thickness of the multilayer sheet including the pressure-sensitive adhesive 2 exemplified in FIG. 1 (thickness including the first and second (meth) acrylic pressure-sensitive adhesive layers and the reinforcing base 3) is, for example, It may be about 200 μm or more, about 400 μm or more, about 600 μm or more, about 800 μm or more, or about 1000 μm or more.

(Reinforcing substrate)
The reinforcing base 3 can be formed of a plurality of fibers 3a intersecting with each other. For example, the reinforcing substrate 3 intersects each other in a state in which a plurality of fibers 3a are oriented in two or more directions or randomly, and the fibers 3a are joined at one of the intersections by one or more of entanglement, fusion, and adhesion. Can do. As such a reinforcing substrate 3, for example, a woven fabric, a knitted fabric, or a non-woven fabric can be used. The woven fabric / knitted fabric here is a multiaxial woven fabric / knitted fabric such as a biaxial woven fabric / knitted fabric or a triaxial woven fabric / knitted fabric in which a plurality of fibers are oriented in two or more directions. The reinforcing substrate 3 is preferably a biaxial woven fabric or a triaxial woven fabric from the viewpoint of suitably reinforcing the concrete structure. The weaving method of the biaxial woven fabric or the triaxial woven fabric may be, for example, plain weave, twill weave, satin weave, leno weave, or imitation weave. In the multilayer sheet 1 shown in FIGS. 1 and 2, a biaxial woven fabric in which a plurality of fibers 3a are woven together in a state of being arranged in two directions (substantially orthogonal directions) is adopted as the reinforcing base 3.

  The fiber 3a may be either a monofilament or a multifilament, but is preferably a monofilament considering the impregnation property of the pressure-sensitive adhesive into the reinforcing base material. The fiber 3a may be formed of at least one of, for example, glass, vinylon, aramid, nylon (polyamide), polyester, polyethylene, and polypropylene. In the case of obtaining a totally transparent multilayer sheet, a reinforcing substrate including at least one fiber 3a out of glass, nylon (polyamide), polyester, and polypropylene can be used. In the case of obtaining a partially transparent multilayer sheet described below, a reinforcing substrate including at least one fiber 3a among polyethylene, vinylon, aramid, and glass can be used. The fiber 3a may be treated with a sealing agent or a sizing agent, but in the case of glass fiber, it is preferable that the fiber 3a is not treated with a sealing agent or a sizing agent. In this case, the impregnation property of the pressure sensitive adhesive to the reinforcing base material is improved.

  When obtaining a totally transparent multilayer sheet as shown in FIG. 7, the refractive index of the reinforcing substrate is about 1.40 or more, about 1.43 or more, or about 1.45 or more, about 1.60 or less, A reinforcing substrate that is about 1.57 or less or about 1.54 or less and that can be impregnated with a pressure-sensitive adhesive is used.

When a multi-filament glass fiber reinforced base material is used to obtain a totally transparent multi-layer sheet, the thickness of the reinforced base material is considered in consideration of the impregnation property of the pressure-sensitive adhesive and the strength of the multi-layer sheet. Is preferably about 0.20 mm or less, about 0.15 mm or less, or about 0.13 mm or less, and the basis weight of the reinforcing substrate is about 40 g / m ² or more, about 50 g / m ² or more, or about 60 g / It is preferable to be m ² or more, about 130 g / m ² or less, about 120 g / m ² or less, or about 110 g / m ² or less. In the case of obtaining a totally transparent multilayer sheet using a reinforcing substrate containing polymer monofilament, the reinforcement is made in consideration of the impregnation property of the pressure-sensitive adhesive, the strength, flexibility and workability of the multilayer sheet. The thickness of the substrate is preferably about 0.40 mm or less, about 0.35 mm or less, or about 0.30 mm or less. The reason why the thickness condition is different between the multifilament glass fiber and the polymer monofilament is that the impregnation property of the pressure-sensitive adhesive is particularly lowered when the multifilament is thick. The thickness of the reinforcing base is reduced from the viewpoint of suppressing the vertical wrinkles caused by the tension in the MD direction applied to the reinforcing base during the production of the totally or partially transparent multi-layered sheet, and preventing the poor thickness and appearance of the multilayer sheet. The thickness is preferably about 0.05 mm or more, about 0.06 mm or more, or about 0.07 mm or more.

  From the viewpoint of suitably reinforcing the concrete structure, the tensile strength of the reinforcing base 3 is preferably about 200 N / 25 mm or more, about 300 N / 25 mm or more, or about 450 N / 25 mm or more, and can be about 2500 N / 25 mm or less. .

  The multilayer sheet for preventing concrete peeling according to another embodiment of the present disclosure includes a first (meth) acrylic pressure-sensitive adhesive layer, and a reinforcing substrate on the first (meth) acrylic pressure-sensitive adhesive layer. A second (meth) acrylic pressure-sensitive adhesive layer on the reinforcing substrate, the reinforcing substrate having an opening length of about 4 mm or more and an opening area of about 40% or more, corresponding to the opening area The part to do has transparency.

  In the multilayer sheet for preventing concrete peeling in this embodiment, the opening length of the reinforcing base is about 4.0 mm or more, about 4.5 mm or more, or about 5.0 mm or more, about 100 mm or less, about 50 mm or less, or about 20 mm or less. The open area may be about 40% or more, about 45% or more, or about 50% or more, and may be about 90% or less, about 85% or less, or about 80% or less, as illustrated in FIG. As long as it is partially transparent, the first and second (meth) acrylic pressure-sensitive adhesive layers and the reinforcing substrate can employ the same configuration as described above. The partially transparent multilayer sheet is sufficient if the (meth) acrylic pressure-sensitive adhesive penetrates into the opening of a predetermined size of the reinforcing substrate, and does not necessarily penetrate between the fibers of the multifilament. Therefore, the refractive index, thickness, and basis weight of the reinforcing substrate may be outside the above ranges, and glass fibers containing a sealing agent and a sizing agent may be used.

  The shape of the opening of the reinforcing substrate is not particularly limited, and for example, a substantially polygonal shape such as a substantially triangular shape (a substantially regular triangle, a substantially isosceles triangle, etc.), a substantially quadrilateral shape (a substantially square shape, a substantially rectangular shape, a substantially rhombus shape, etc.) is used. be able to. Among these, a substantially square opening is preferable from the viewpoints of low strength anisotropy in the vertical and horizontal directions, ease of penetration of the pressure-sensitive adhesive into the opening, cost, and the like.

  The reinforcing substrate 3 is disposed in the pressure sensitive adhesive 2. That is, the pressure sensitive adhesive 2 is present on both main surfaces of the reinforcing base 3, and both main surfaces of the reinforcing base 3 are not exposed. As shown in FIG. 2, the opening formed between the plurality of fibers 3 a forming the reinforcing base 3 is filled with the pressure-sensitive adhesive 2. Therefore, when the first (meth) acrylic pressure-sensitive adhesive layer and the second (meth) acrylic pressure-sensitive adhesive layer are formed of the same material, these adhesive layers are two layers. It can also be regarded as a single configuration rather than a configuration. Since the pressure sensitive adhesive 2 fills the openings between the fibers, the movement of the fibers is suppressed, so that the stripping prevention performance of the concrete pieces can be further improved.

  At least one of the thicknesses (average values) between the main surfaces of the pressure-sensitive adhesive 2 facing both the main surfaces of the reinforcing base 3 is about 10 μm or more, about 30 μm or more, or about 50 μm or more. preferable. A concrete structure can be suitably reinforced by sticking the main surface of the pressure-sensitive adhesive 2 on the thickness (average value) side or more to the concrete structure.

  FIG. 3 is a cross-sectional view showing another embodiment of the concrete peeling prevention multilayer sheet. As shown in FIG. 3, the concrete peeling prevention multilayer sheet 11 of the present disclosure may further include a transparent polymer layer 5 on one side of the pressure-sensitive adhesive 2.

(Polymer layer)
The polymer layer 5 may be a material that functions as a protective layer capable of imparting at least one performance such as weather resistance, antifouling property, waterproofness, and salt barrier property. For example, polyethylene, polypropylene, polyester, polycarbonate, One or more resins such as vinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyurethane, acrylic polymer, silicone, and fluorine polymer can be used. Of these, fluorine-based polymers are preferable. Examples of fluorine-based polymers include polyvinyl fluoride, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and polychlorotrifluoroethylene. One or more of ethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and the like can be used. The polymer layer 5 is added with the above-mentioned fillers, plasticizers, pigments, dyes, reinforcing agents, reinforcing agents, flame retardants, ultraviolet absorbers, antioxidants, stabilizers and the like as long as they do not cause problems with transparency. An agent may be included.

  The polymer layer 5 may be formed by melt-extruding the above resin on a pressure-sensitive adhesive layer and laminating it by painting, solvent casting, or the like, and applying a pre-molded film or sheet form to the pressure-sensitive adhesive layer. Also good. The polymer layer 5 may be a single layer or a multilayer configuration. In addition, in order to improve the adhesion between the polymer layer and the pressure-sensitive adhesive layer, it is possible to subject the laminate surface of the polymer layer with the pressure-sensitive adhesive to easy adhesion treatment such as corona treatment, plasma treatment, and primer treatment. .

  The thickness of the polymer layer 5 may be, for example, about 1 μm or more, about 5 μm or more, or about 10 μm or more, about 1000 μm or less, about 500 μm or less, or about 100 μm or less.

  The multilayer sheet for preventing concrete peeling of the present disclosure is used by bonding the main surface of the pressure-sensitive adhesive layer opposite to the polymer layer to the concrete structure. The polymer layer may be bonded to the pressure-sensitive adhesive layer in advance before construction, or after one pressure-sensitive adhesive layer is bonded to the concrete structure, the polymer is applied to the other pressure-sensitive adhesive layer. The layers may be bonded together.

  The thickness (average value) T1 between the main surface of the pressure-sensitive adhesive layer opposite to the polymer layer 5 and the main surface of the reinforcing base 3 shown in FIG. 3 can suitably reinforce the concrete structure. From the viewpoint, it is preferably about 10 μm or more, about 30 μm or more, or about 50 μm or more. The thickness (average value) T2 between the main surface of the pressure-sensitive adhesive layer on the polymer layer 5 side and the main surface of the reinforcing base 3 is about 10 μm or more, or about 20 μm or more, about 300 μm or less, or about 100 μm. It may be the following. The total thickness of the pressure-sensitive adhesive 2 including the thicknesses of T1 and T2 and the reinforcing base 3 (the vertical distance in FIG. 3) is 300 μm (0.3 mm) or more, 600 μm (0.6 mm) or more, 1000 μm ( 1 mm) or more.

The concrete peeling prevention multilayer sheets 1 and 11 of the present disclosure can be manufactured by, for example, the following method.
(1) A first (meth) acrylic pressure-sensitive adhesive layer is formed on the peelable substrate or the polymer layer 5 in the form of a film or sheet by, for example, applying an ultraviolet curable pressure-sensitive adhesive, The first (meth) acrylic pressure-sensitive adhesive layer is cured by irradiating ultraviolet rays as necessary.
(2) The reinforcing substrate 3 is disposed on the first (meth) acrylic pressure-sensitive adhesive layer. When the first (meth) acrylic pressure-sensitive adhesive layer is uncured, the reinforcing base material 3 is impregnated with part or all of the pressure-sensitive adhesive layer when the reinforcing base material 3 is disposed. Or you may make it penetrate | invade into the opening part of the reinforcement base material 3. FIG.
(3) A second (meth) acrylic pressure-sensitive adhesive layer is formed on the reinforcing base 3 by, for example, applying an ultraviolet curable pressure-sensitive adhesive, and the reinforcing base 3 is not impregnated or intruded. If there is a portion, the pressure-sensitive adhesive layer is partially impregnated into the reinforcing base 3 or penetrated into the opening of the reinforcing base 3 and irradiated with ultraviolet rays as necessary. The (meth) acrylic pressure-sensitive adhesive layer is cured. When the first (meth) acrylic pressure-sensitive adhesive layer is uncured, the pressure-sensitive adhesive layer can be cured at the same time.
(4) When a release substrate is used in the step (1), the second (meth) acrylic pressure sensitivity is optionally obtained by, for example, coating, melt-extruding the polymer layer 5 and bonding in the form of a film or sheet. It can be applied on the adhesive layer. After the polymer layer 5 is applied, the first and second (meth) acrylic pressure-sensitive adhesive layers may be cured by irradiating with ultraviolet rays.

  The multilayer sheet for preventing concrete from peeling off may be an aspect other than the above embodiment. For example, the multilayer sheet for preventing concrete peeling may include a peelable substrate on both main surfaces of the first and second (meth) acrylic pressure-sensitive adhesive layers.

The concrete peeling prevention multilayer sheets 1 and 11 of the present disclosure can be applied to the concrete structure 4 by the following method, for example.
(1) Optionally, a surface treatment agent is applied to the concrete structure 4 and dried, and if necessary, heat or light is applied to form a surface treatment layer.
(2) The pressure sensitive adhesive layer of the concrete peeling prevention multilayer sheets 1 and 11 is applied to the concrete structure 4 directly or via a surface treatment layer.
(3) Optionally, the polymer layer 5 is further applied to the pressure-sensitive adhesive layer on the opposite side of the concrete structure 4 of the concrete peeling prevention multilayer sheet 1.

  From the viewpoint of preventing cracks in the concrete structure, a surface treatment agent such as an acrylic adhesive or an epoxy adhesive is applied to the surface of the concrete structure before the multilayer sheet for preventing concrete peeling is applied to the concrete structure. Can do. The surface treatment agent may be an accelerating curable resin that accelerates curing when given heat, light, moisture, or the like. The applied surface treatment layer may have a function as a primer layer for the multilayer sheet for preventing concrete peeling.

  The multilayer sheet for preventing concrete stripping of the present disclosure is suitable for preventing the stripping of concrete pieces from concrete structures such as bridges, tunnels, and elevated roads, and simply sticking the multilayer sheet for preventing concrete stripping to the concrete structure. The concrete structure can be suitably reinforced only by this, and the appearance change of the concrete structure can be observed over time.

  In the following examples, specific embodiments of the present disclosure are illustrated, but the present invention is not limited thereto. All parts and percentages are by weight unless otherwise specified.

  The reagents and raw materials used in this example are shown in Table 1 below.

(Overall transparent multi-layer sheet for preventing concrete peeling)
<Example 1>
91 parts by mass of 2EHA, 9 parts by mass of AA, and 0.04 parts by mass of a photopolymerization initiator (Irgacure 651) were mixed in a glass container purged with nitrogen. The resulting mixture was irradiated with 0.5 mW / cm ² of ultraviolet light to partially polymerize the mixture. 0.08 parts by mass of HDDA and 0.1 parts by mass of a photopolymerization initiator (Irgacure 651) were added to the mixture after irradiation with ultraviolet light to obtain a pressure sensitive adhesive A having a viscosity of 2000 mPa · s.

Next, on the peelable PET film treated with silicone, the obtained pressure-sensitive adhesive A was knife-coated with a thickness of 500 μm to form a first (meth) acrylic pressure-sensitive adhesive layer, and the adhesive A glass fiber cloth 2116 was placed on the layer. On the glass fiber cloth 2116, the obtained pressure-sensitive adhesive A was tandem-coated with a thickness of 500 μm and impregnated to form a second (meth) acrylic pressure-sensitive adhesive layer. Next, another peelable PET film treated with silicone is placed on the second (meth) acrylic pressure-sensitive adhesive layer, and 0.5 mW / cm ² (total energy: The pressure sensitive adhesive layer was cured by irradiating the ultraviolet light of 1J).

  After curing, the peelable PET film on one side was removed, and a TEFKA film as a polymer layer was laminated on the removed surface to obtain a multilayer sheet for preventing concrete peeling (FIG. 7).

<Example 2>
A multilayer sheet for preventing concrete peeling was produced in the same manner as in Example 1 except that the reinforcing base material was changed to mesh NB80 (FIG. 7).

<Comparative Example 1>
An opaque pressure-sensitive adhesive B having a viscosity of 10,000 mPa · s or less by further blending 2.0 parts by mass of A200 fumed silica and 6.0 parts by mass of Glass Bubbles K15 into the pressure-sensitive adhesive A of Example 1; Except for the above, a multilayer sheet for preventing concrete exfoliation was produced in the same manner as in Example 1 (FIG. 8).

<Comparative example 2>
87.5 parts by mass of 2EHA, 12.5 parts by mass of AA, and 0.04 parts by mass of a photopolymerization initiator (Irgacure 651) were mixed in a glass container purged with nitrogen. The resulting mixture was irradiated with 0.5 mW / cm ² of ultraviolet light to partially polymerize the mixture. 0.08 parts by mass of HDDA and 0.1 part by mass of a photopolymerization initiator (Irgacure 651) were added to the mixture after irradiation with ultraviolet light to obtain a pressure sensitive adhesive C having a viscosity of 2000 mPa · s or less.

Subsequently, the pressure-sensitive adhesive C obtained was knife-coated with a thickness of 1000 μm on a peelable PET film treated with silicone to form a (meth) acrylic pressure-sensitive adhesive layer. Next, another peelable PET film treated with silicone was placed on the (meth) acrylic pressure-sensitive adhesive layer, and 0.5 mW / cm ² (total energy: 1 J) using a UV-A lamp. The pressure sensitive adhesive layer was cured by irradiating UV light.

  After curing, the peelable PET film on one side was removed, and a TEFKA film was laminated on the removal surface to obtain a multilayer sheet for preventing concrete peeling that did not contain a reinforcing substrate (FIG. 8).

<Comparative Example 3>
The pressure-sensitive adhesive C obtained in Comparative Example 2 was knife-coated with a thickness of 500 μm on a silicone-peelable PET film to form a first (meth) acrylic pressure-sensitive adhesive layer, Another peelable PET film treated with silicone is placed on the first (meth) acrylic pressure-sensitive adhesive layer, and 0.5 mW / cm ² (total energy: 1 J) using a UV-A lamp. The pressure sensitive adhesive layer was cured by irradiating UV light. Two pressure-sensitive adhesive sheets including the cured pressure-sensitive adhesive layer were prepared.

  The peelable PET film on one side of one pressure-sensitive adhesive sheet was removed, and a glass fiber cloth 2116 was laminated on the removal surface. Next, the peelable PET film on one side of the other pressure-sensitive adhesive sheet was removed, and the sheet was laminated on the glass fiber cloth 2116 to form a second (meth) acrylic pressure-sensitive adhesive layer. Further, the other peelable PET film of the pressure-sensitive adhesive layer was removed, and a TEFKA film was laminated on the removed surface to obtain a multilayer sheet for preventing concrete peeling that was not impregnated with the pressure-sensitive adhesive ( FIG. 8).

<Reference Example 1>
Only the glass fiber cloth 2116 which is a reinforcing base material is configured (FIG. 9).

<Reference Example 2>
Only the mesh NB80, which is a reinforcing base material, is configured (FIG. 9).

  The following concrete exfoliation prevention evaluation test 1 and transparency test 1 were performed on each of the above concrete exfoliation multilayer sheets.

(Concrete peeling prevention evaluation test 1)
The multilayer sheet 11 for preventing concrete peeling was cut into a size of 70 mm × 110 mm to prepare a multilayer sheet 11 for a sample. As shown in FIG. 6, the multilayer sheet 11 was fixed on the lower metal block 14 with the fixing tool 13 so that the polymer layer side of the multilayer sheet 11 became the upper surface. Next, the upper metal block 12 having a size of 30 mm × 30 mm was oscillated from the upper side to the lower side to punch out the multilayer sheet 11. The test was performed at room temperature, the amplitude was 25 mm, the wavelength was 0.1 Hz, the displacement amount and the load of the upper metal block 12 were observed, and the maximum load obtained was defined as the maximum punching strength. Here, the amplitude of 25 mm means that the upper surface of the multilayer sheet is 0 mm as a reference and the lower end of the upper metal block 12 is positioned 25 mm above (+25 mm) from the upper surface of the multilayer sheet, and the upper metal block 12 is positioned below. Is moved to a position in contact with the multi-layer sheet, and further moved downward by 25 mm (−25 mm). In concrete peeling prevention evaluation test 1, the maximum punching strength is 500 N or more, preferably 800 N or more, more preferably 1100 N or more. When the maximum punching strength is within this range, it is desirable for use as a multilayer sheet for preventing concrete peeling.

(Transparency test 1)
The multilayer sheet for preventing concrete exfoliation was applied on a concrete structure having a predetermined crack, and the transparency was visually observed. Those that could not observe a hairline crack of 0.3 mm or less in a concrete structure or those that had a problem with the appearance after construction "+", those that could observe a hairline crack of 0.3 mm or less and more than 0.1 mm “++” was defined as “++” where hairline cracks of 0.1 mm or less could be observed.

(Partially transparent multilayer sheet for preventing concrete peeling)
<Example 3>
A multilayer sheet for preventing concrete peeling was produced in the same manner as in Example 1 except that the reinforcing base material was changed to CRENETTE (registered trademark) DN1000 (FIG. 10).

<Example 4>
A multilayer sheet for preventing concrete exfoliation was produced in the same manner as in Example 1 except that the reinforcing base material was changed to CRENETTE (registered trademark) VHA1102 (FIG. 10).

<Comparative Example 4>
A multilayer sheet for preventing concrete peeling was produced in the same manner as in Example 1 except that the reinforcing substrate was changed to glass cloth M340 (FIG. 11).

<Comparative Example 5>
The pressure-sensitive adhesive A obtained in Example 1 was knife-coated with a thickness of 500 μm on a silicone-treated peelable PET film to form a first (meth) acrylic pressure-sensitive adhesive layer. Another peelable PET film treated with silicone was placed on 1 (meth) acrylic pressure-sensitive adhesive layer, and 0.5 mW / cm ² (total energy: 1 J) using a UV-A lamp. The pressure sensitive adhesive layer was cured by irradiation with ultraviolet light. Two pressure-sensitive adhesive sheets including the cured pressure-sensitive adhesive layer were prepared.

  The peelable PET film on one side of one pressure-sensitive adhesive sheet was removed, and CRENETTE (registered trademark) DN1000 was laminated on the removal surface. Next, the peelable PET film on one side of the other pressure-sensitive adhesive sheet is removed and the sheet is laminated on CRENETTE (registered trademark) DN1000 to form a second (meth) acrylic pressure-sensitive adhesive layer. did. Furthermore, the other peelable PET film of this pressure-sensitive adhesive layer is removed, and a TEFKA film is laminated on the removal surface to prevent the concrete from peeling off without allowing the pressure-sensitive adhesive to penetrate into the opening of the reinforcing substrate. A multilayer sheet was obtained (FIG. 11).

  Table 3 shows the results of the concrete peeling prevention evaluation test 1 and the transparency test 1 in Examples 3 to 4 and Comparative Examples 4 to 5.

(Concrete peeling prevention evaluation test 2)
Measured according to NEXCO test method 424-2011. First, as shown in FIGS. 4 and 5, a core portion having a remaining portion having an inner diameter of 100 mm, a groove width of 5 mm, and a depth of 55 mm by a concrete core cutter at the center of a concrete block 7 having a length of 400 mm, a width of 600 mm, and a height of 60 mm. Formed. Alpha primer 380 was applied to the surface of the concrete block 7 opposite to the core portion to form a primer layer, and then a concrete peeling prevention multilayer sheet was applied. The construction area was 400 mm long and 400 mm wide. Next, as shown in FIGS. 4 and 5, the concrete block 7 was installed at a position of a height h or higher where the peeling resistance of the punching tester 6 can be confirmed in an atmosphere of 50 ° C. or −30 ° C. The core part of the concrete block 7 was loaded at a speed of 1 mm / min in the direction of the arrow through the spherical seat 8 until the remaining part of the core part was broken. After breaking, the load was applied at 5 mm / min to give a forced displacement to the concrete peeling prevention multilayer sheet, and the load and displacement were continuously recorded with a load meter 9 and a displacement meter 10. Meanwhile, the loading was temporarily interrupted at displacements of 10 mm, 20 mm, and 30 mm, and the peeling range of the multilayer sheet for preventing concrete peeling was measured (marking). When the final load bearing capacity could be confirmed while the displacement was up to 30 mm, the test was terminated at that point. Furthermore, when it was judged that it had load bearing capacity, loading was continued to about 50 mm. In addition, the thing with the largest maximum load and small maximum displacement amount shows that it is excellent in peeling prevention property. The acceptance criteria for the reinforcing member of the concrete structure is 1.5 kN or more in the NEXCO test method. In addition, in the test method of the Metropolitan Expressway Co., Ltd. other than the NEXCO test method, the maximum load of 0.3 kN or more and less than 1.5 kN is distinguished from the B type and the 1.5 kN or more is distinguished from the A type. However, the measurement temperature is set to room temperature (23 ° C) instead of 50 ° C or below zero. In the case of the measurement temperature of this metropolitan expressway, the maximum load when measured at 50 ° C or below zero. It is predicted that the value will be higher than the value (even if the material has a lower mechanical strength than the level of Type A or Type B). In this way, the required performance of the maximum load varies depending on the application, but it is one guideline that exceeds the level of the acceptance standard of the NEXCO test method. It can be said that exceeding the B level continues.

  Concrete peeling prevention evaluation test 2 was performed on the concrete peeling prevention multilayer sheets in Examples 5 to 7 below, and the results are shown in Table 4.

<Example 5>
Concrete that is totally transparent in the same manner as in Example 1 except that the blending amounts of 2EHA and AA are changed to 90 parts by mass and 10 parts by mass, and the reinforcing base and the polymer layer are changed to H105H and DX film. A multilayer sheet for preventing peeling was prepared.

<Example 6>
A partially transparent concrete exfoliation multilayer sheet was produced in the same manner as in Example 5 except that the reinforcing base material was changed to CRENETTE (registered trademark) VHA1102.

<Example 7>
A partially transparent concrete exfoliation multilayer sheet was produced in the same manner as in Example 5 except that the reinforcing base material was changed to CRENETTE (registered trademark) DN1000.

  As shown in Table 4, in the concrete exfoliation prevention evaluation test 2 of the present disclosure, Examples 5 to 7 show a value of 1.5 kN or more corresponding to the acceptance standard of the NEXCO test method, and are particularly high in applications for preventing concrete exfoliation. The maximum load requirement is met.

  For reference, the results of the concrete peeling prevention evaluation tests 2 and 1 of the present disclosure are compared. Example 6 and Example 4 use the same reinforcing base material CRENETTE (registered trademark) VHA1102, and Example 7 and Example 3 use the same reinforcing base material CRENETTE (registered trademark) DN1000. Considering that the blending amount of 2EHA and AA is a difference of 1 part by mass, and that the polymer layer on the surface does not have a great influence on the maximum load, Examples 6 and 7 satisfying the acceptance criteria of the NEXCO test method and Examples 4 and 3 are estimated to show approximate maximum loads. Therefore, Examples 1-4 which exceed 1100N which is near the standard of maximum punching strength 1289N and 1158N which are the results of the concrete peeling prevention evaluation test 1 of Examples 4 and 3 are particularly high maximum loads in the concrete peeling prevention application. It is estimated that this requirement is satisfied.

(Comparative test on transparency)
<Comparative Example 6>
The mortar plate was ground with a No. 150 polishing cloth and subjected to a ground treatment, and then Alphatech 380 was applied to form a primer layer. After drying for 24 hours, hard rock II DK550-003 was applied onto the primer layer, a NAV sheet was placed on it, and hard rock II DK550-003 was overcoated, and the concrete structure according to the conventional construction method Repair was carried out. The result is shown on the left side of FIG. 13, and the right side shows a photograph of the appearance after applying the concrete peeling prevention multilayer sheet of Example 1 to the concrete structure. Even in the conventional construction method of Comparative Example 6, although a certain degree of transparency is obtained, the uneven surface based on the reinforcing base material, coating unevenness, etc. can be clearly confirmed, compared with that of Example 1 of the present embodiment, It was confirmed that the transparency was clearly inferior. In addition, the appearance of the repaired part by the conventional method of Comparative Example 6 largely depends on the amount of adhesive applied, the skill level of the operator, and the like, and the same visibility as in Example 1 of the embodiment of the present application is stable. It can be easily predicted that it is difficult to obtain.

(Transparency test 2)
A measurement sample (reinforcing base material or multilayer sheet for preventing concrete peeling) was placed so as to cover the light receiving part of a color illuminometer (manufactured by Konica Minolta: CL-200A), and the illuminance (LX ₁ ) of each sample was measured. . Based on the illuminance (LX ₀ ) when the measurement sample is not covered with the light receiving portion, the light transmittance of each measurement sample was calculated from the following equation (3). The results are shown in Tables 5 and 6. Here, Table 5 shows the results of various samples prepared in the same manner as in Example 1 except for Examples 1 and 2 and the reinforcing base material of the multilayer sheet for preventing concrete exfoliation as a whole, and Table 6 shows the results. These are the results of Examples 3 and 4 and Comparative Example 4 of the partially transparent multilayer sheet for preventing concrete peeling. In addition, the result of Table 6 is based on the illumination intensity obtained by irradiating light to the sample including both the lattice portion and the opening portion.

  It will be apparent to those skilled in the art that various modifications can be made to the embodiments and examples described above without departing from the basic principles of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

DESCRIPTION OF SYMBOLS 1,11 Multilayer sheet for concrete peeling prevention 2 Pressure sensitive adhesive 3 Reinforcement base material 3a Fiber 4 Concrete structure 5 Polymer layer 6 Punching test machine 7 Concrete block 8 Spherical seat 9 Load meter 10 Displacement meter 12 Upper metal block 13 Fixation Tool 14 Lower metal block

Claims (14)

A first (meth) acrylic pressure sensitive adhesive layer;
A reinforcing substrate on the first (meth) acrylic pressure sensitive adhesive layer;
A second (meth) acrylic pressure-sensitive adhesive layer on the reinforcing substrate, and a multilayer sheet for preventing concrete peeling,
The refractive index of the reinforcing substrate is 1.40 to 1.60,
A multilayer sheet for preventing concrete peeling, wherein the reinforcing base material is impregnated with an adhesive of the first and / or second (meth) acrylic pressure-sensitive adhesive layer. A first (meth) acrylic pressure sensitive adhesive layer;
A reinforcing substrate on the first (meth) acrylic pressure sensitive adhesive layer;
A second (meth) acrylic pressure-sensitive adhesive layer on the reinforcing substrate, and a multilayer sheet for preventing concrete peeling,
The reinforcing substrate has an opening length of 4.0 mm or more and an opening area of 40% or more;
A multilayer sheet for preventing concrete from peeling off, wherein a portion corresponding to the opening region is transparent.   The multilayer sheet for concrete peeling prevention according to claim 1 or 2 in which said reinforced substrate contains glass fiber or polymer monofilament. It said reinforcing comprises a substrate of glass fiber, thickness and basis weight of the reinforcing substrate is 0.20mm or less and 40~130g / ^{m 2,} the multilayer sheet for concrete spalling prevention according to claim 1, wherein.   The multilayer sheet for preventing concrete peeling according to claim 1, wherein the reinforcing base material contains a polymer monofilament, and the thickness of the reinforcing base material is 0.40 mm or less.   The multilayer sheet for preventing concrete exfoliation according to claim 1 or 4 in which said reinforcing substrate contains glass fiber which has not been processed with a sealant and a bundling agent.   The multilayer sheet for preventing concrete peeling according to any one of claims 1 to 6, wherein the reinforcing substrate has a tensile strength and thickness of 200 N / 25 mm or more and 0.05 mm or more.   The multilayer sheet for preventing concrete exfoliation according to any one of claims 1 to 7, comprising a polymer layer on the side opposite to the reinforcing substrate side of the first or second (meth) acrylic pressure-sensitive adhesive layer. .   The multilayer sheet for preventing concrete from peeling off according to claim 8, wherein the polymer layer is a fluoropolymer layer.   The multilayer sheet for concrete peeling prevention according to any one of claims 1 to 9, wherein the first and / or second (meth) acrylic pressure-sensitive adhesive layer does not contain a filler. Providing a first (meth) acrylic pressure sensitive adhesive layer, the pressure sensitive adhesive layer comprising an ultraviolet curable pressure sensitive adhesive; and
Providing a reinforcing substrate on the first (meth) acrylic pressure sensitive adhesive layer;
Providing a second (meth) acrylic pressure sensitive adhesive layer on the reinforcing substrate, the pressure sensitive adhesive layer comprising an ultraviolet curable pressure sensitive adhesive;
The multilayer sheet for preventing concrete peeling according to any one of claims 1 to 10, comprising a step of irradiating ultraviolet rays to cure the first and second (meth) acrylic pressure-sensitive adhesive layers. Manufacturing method.   The method for producing a multilayer sheet for preventing concrete exfoliation according to claim 11, wherein the viscosity of the partial polymer of the ultraviolet curable pressure-sensitive adhesive is 10,000 mPa · s or less. A construction method of a multilayer sheet for preventing the concrete structure from peeling off,
The construction method provided with the process of applying the multilayer sheet for concrete peeling prevention as described in any one of Claims 1-10 directly to a concrete structure, or a process applied to a concrete structure through a surface treatment layer. Providing a first (meth) acrylic pressure sensitive adhesive layer comprising an ultraviolet curable pressure sensitive adhesive;
Providing a reinforcing substrate having a refractive index of 1.40 to 1.60 on the first (meth) acrylic pressure-sensitive adhesive layer;
Providing and impregnating a second (meth) acrylic pressure sensitive adhesive layer containing an ultraviolet curable pressure sensitive adhesive on the reinforcing substrate;
And a step of curing the first and second (meth) acrylic pressure-sensitive adhesive layers simultaneously or separately by irradiating with ultraviolet rays.