JP6811669B2 - Evidence collection sheet - Google Patents

Description

The present invention relates to a sheet for collecting evidence.

For example, an adhesive sheet for forensics is used for collecting fine evidence such as hair and skin pieces in criminal forensics (see, for example, Patent Document 1).

The forensic pressure-sensitive adhesive sheet described in Patent Document 1 has a pressure-sensitive adhesive layer formed by irradiating a layer made of an acrylic pressure-sensitive adhesive composition containing a specific component with light and cross-linking the layer. According to the forensic adhesive sheet described in Patent Document 1, the evidence product can be collected by adhering the evidence product with the pressure-sensitive adhesive layer, and the evidence product can be stored by attaching a film to the pressure-sensitive adhesive layer in that state. ..

However, with the conventional adhesive sheet for forensics, the shape of the evidence may be deformed during the preservation of the evidence.

Japanese Unexamined Patent Publication No. 2008-308522

An object of the present invention is to provide a sheet for collecting evidence, which can easily collect evidence and does not easily deform the evidence when it is stored.

Such an object is achieved by the present invention described in the following (1) to (7).
(1) Base material and
A first pressure-sensitive adhesive layer provided on one surface side of the base material and containing a material having ultraviolet curability,
On the other surface side of the base material, a removable protective sheet having an ultraviolet shielding property and
A sheet for collecting evidence, which is provided on the surface side of the first pressure-sensitive adhesive layer opposite to the surface facing the base material, and includes a release liner that protects the first pressure-sensitive adhesive layer.

(2) The protective sheet has a protective sheet base material and a second pressure-sensitive adhesive layer in contact with the base material.
The evidence-collecting sheet according to (1) above, wherein the material having an ultraviolet shielding property is contained in the base material.

(3) The protective sheet has a protective sheet base material and a second pressure-sensitive adhesive layer in contact with the base material.
The evidence-collecting sheet according to (1) or (2) above, wherein the material having an ultraviolet shielding property is contained in the second pressure-sensitive adhesive layer.

(4) The protective sheet according to any one of (1) to (3) above, which has visible light transmittance.

(5) The evidence collecting sheet according to any one of (1) to (4) above, wherein the material having an ultraviolet shielding property is at least one of a triazine compound, a benzotriazole compound and a benzophenone compound. ..

(6) The evidence-collecting sheet according to any one of (1) to (5) above, wherein the release liner has visible light absorption.

(7) The sheet for collecting evidence according to any one of (1) to (6) above, wherein the release liner has an ultraviolet shielding property.

According to the present invention, since the adhesive layer is provided, evidence can be easily collected. Further, when the adhesive layer is irradiated with ultraviolet rays while the protective sheet is peeled off and the evidence is preserved, the adhesive layer is cured. As a result, even if an external force is applied to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is prevented from being deformed, so that the shape of the evidence can be prevented from being deformed. Furthermore, since the protective sheet has an ultraviolet shielding property, ultraviolet rays adhere to the protective sheet and the base material in an unused state (a state in which evidence has not been collected) in which the evidence collecting sheet has not been used yet. It is possible to prevent the agent layer from being irradiated. Therefore, it is possible to prevent the pressure-sensitive adhesive layer from being unintentionally cured by ultraviolet rays before collecting evidence. As a result, the adhesive strength of the pressure-sensitive adhesive layer is surely maintained when the evidence product is collected.

It is a schematic vertical sectional view which shows the preferable embodiment of the evidence-collecting sheet of this invention, and is the figure which shows the unused state. It is a schematic vertical sectional view which shows the preferable embodiment of the evidence collecting sheet of this invention, and is the figure which shows the state which collects. It is a schematic vertical sectional view which shows the preferable embodiment of the evidence-collecting sheet of this invention, and is the figure which shows the preservation state.

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Evidence collection sheet]
FIG. 1 is a schematic vertical cross-sectional view showing a preferred embodiment of the evidence collecting sheet of the present invention, and is a diagram showing unused. FIG. 2 is a schematic vertical cross-sectional view showing a preferred embodiment of the evidence collecting sheet of the present invention, and is a diagram showing a state of collecting. FIG. 3 is a schematic vertical cross-sectional view showing a preferred embodiment of the evidence collecting sheet of the present invention, and is a diagram showing a stored state.

As shown in FIG. 1, the evidence collecting sheet 10 is used, for example, for collecting evidence (evidence) of an incident. The evidence collecting sheet 10 is provided on one surface side of the base material 1, the base material 1, and the pressure-sensitive adhesive layer 2 (first pressure-sensitive adhesive layer) containing a material having ultraviolet curability, and the base material 1. A peelable protective sheet 5 having an ultraviolet shielding property is provided on the other surface side, and the adhesive layer 2 is provided on the surface opposite to the surface facing the base material 1 of the adhesive layer 2 to protect the adhesive layer 2. The peeling liner 3 is provided.

In this evidence collecting sheet 10, the release liner 3 is peeled from the adhesive layer 2 from an unused state (a state in which the evidence product 200 has not been collected) (see FIG. 1), and the evidence product 200 is removed. It is collected by adhering it to the pressure-sensitive adhesive layer 2 (see FIG. 2). Then, as shown in FIG. 3, the release liner 3 is adhered to the pressure-sensitive adhesive layer 2 again, and the evidence product 200 is sandwiched between the pressure-sensitive adhesive layer 2 and the release liner 3 (hereinafter, this state is referred to as this state). Evidence 200 is stored in the state of preservation). The protective sheet 5 is attached to the base material 1 in an unused state, and is peeled off from the base material 1 in a stored state.

According to the present invention as described above, since the pressure-sensitive adhesive layer 2 is provided, the evidence product 200 can be easily collected. Further, when the adhesive layer 2 is irradiated with ultraviolet rays while the protective sheet 5 is peeled off and the evidence is preserved, the adhesive layer 2 is cured. As a result, even if an external force is applied to the pressure-sensitive adhesive layer 2, the pressure-sensitive adhesive layer 2 is prevented from being deformed, so that the shape of the evidence product 200 can be prevented from being deformed. Further, since the protective sheet 5 has an ultraviolet shielding property, it is possible to prevent the adhesive layer 2 from being irradiated with ultraviolet rays through the protective sheet 5 and the base material 1 in an unused state. Therefore, it is possible to prevent the pressure-sensitive adhesive layer 2 from being unintentionally cured by ultraviolet rays before collecting the evidence product 200. As a result, the adhesive strength of the pressure-sensitive adhesive layer 2 is surely maintained when the evidence product is collected.

Examples of the "evidence item (evidence)" include hair, skin pieces, other fine particles, fingerprints, blood, blood stains, footprints, and the like. In addition, the evidence product includes powders, reagents, and the like for detecting evidence products such as fingerprints. A set of the powders and reagents is also included in the evidence product, and the shape formed by the set may be treated as the shape of the evidence product.

Further, in the present specification, "ultraviolet light" refers to light having a wavelength of 200 nm or more and 400 nm or less, and "visible light" refers to light having a wavelength of 400 nm or more and 780 nm or less.

<Base material>
The base material 1 is a portion having a function of supporting the pressure-sensitive adhesive layer 2.

The base material 1 is preferably one having visible light transmission regardless of whether it is colored or colorless. As a result, the evidence product sandwiched between the pressure-sensitive adhesive layer 2 and the release liner 3 can be visually recognized via the base material 1. Therefore, the information of the evidence product can be visually recognized in the stored state.

Examples of the constituent material of the base material 1 include polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; acetates such as cellulose triacetate and cellulose diacetate; and polyolefins such as polyethylene and polypropylene.

Further, the base material 1 may contain components other than those described above. Examples of such components include colorants such as dyes and pigments, antioxidants such as anilides and phenols, modifiers, rust inhibitors, fillers, surface lubricants, corrosion inhibitors, and heat stabilizers. , Lubricants, antioxidants, polymerization inhibitors, cross-linking agents, catalysts, plasticizers, leveling agents, thickeners, softeners, dispersants and the like.
The base material 1 may be a porous body or a laminated body having a plurality of layers.

Further, the base material 1 may be made of, for example, a functionally graded material whose composition changes in a gradient in the thickness direction.

Further, the base material 1 may be surface-treated to improve the adhesion to the pressure-sensitive adhesive layer 2.

Examples of such a surface treatment include application of a polyester-based, polyurethane-based, acrylic-based primer, and corona treatment.

The thickness of the base material 1 is not particularly limited, but is preferably 15 μm or more and 500 μm or less, and more preferably 20 μm or more and 200 μm or less.

Such a base material 1 preferably has a visible light (total light) transmittance of 30% or more and 99% or less, and 50% or more and 98% or less, as measured in accordance with JIS K 7361-1. Is more preferable. This makes it easier to see the evidence product through the base material 1. If the transmittance of visible light is too low, it becomes difficult to visually recognize the evidence product through the base material 1. On the other hand, if the transmittance of visible light is too high, it becomes difficult to select the material for the base material 1.

Such a base material 1 preferably has an ultraviolet transmittance of 5% or more and 90% or less, and more preferably 50% or more and 85% or less, as measured in accordance with JIS S 3107. As a result, as will be described later, when the pressure-sensitive adhesive layer 2 is irradiated with ultraviolet rays through the base material 1 to be cured, the pressure-sensitive adhesive layer 2 can be sufficiently irradiated with ultraviolet rays, and the irradiation times of the ultraviolet rays are compared. Can be shortened.

<Adhesive layer>
The pressure-sensitive adhesive layer 2 of the evidence collection and storage sheet of the present embodiment has ultraviolet curability.

As used herein, the term "ultraviolet curable" means that when irradiated with ultraviolet rays, a polymerization reaction occurs and the material is cured. For example, even if the pressure-sensitive adhesive layer is produced by irradiating it with ultraviolet rays and cross-linking it, the pressure-sensitive adhesive layer that does not cure even if it is irradiated with ultraviolet rays after production is not treated as ultraviolet curable.

The UV-curable pressure-sensitive adhesive layer 2 is cured by UV irradiation. Ultraviolet rays are obtained from LED lamps, high-pressure mercury lamps, electrodeless lamps, metal halide lamps, xenon lamps, etc., and their peak illuminance is 1 to 1000 mW / cm ² . Integrated quantity of ultraviolet light may include normal ^{50~1000mJ / cm 2, 50~300mJ / cm} 2 is preferred.

As an example of an index showing the property of ultraviolet curability, the change in elastic modulus of the pressure-sensitive adhesive layer 2 before and after being irradiated with ultraviolet rays can be adopted. For example, as an example of the ultraviolet curable pressure-sensitive adhesive layer 2, the value of the tensile storage elastic modulus of the pressure-sensitive adhesive layer at 23 ° C. is increased by irradiation with ultraviolet rays. Since the value of the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 is increased by irradiation with ultraviolet rays, the pressure-sensitive adhesive layer is less likely to be deformed, and the pressure-sensitive adhesive layer 2 and / or the pressure-sensitive adhesive layer 2 is attached after the evidence product 200 is collected. It is prevented that the shape of the evidence product 200 is deformed during storage, and the storage stability of the evidence is improved.

Regarding the change in elastic modulus, the ratio of the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 after UV irradiation at 23 ° C. to the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 before UV irradiation at 23 ° C. is preferably 3 or more. It is more preferably 10 or more and 1000 or less, further preferably 100 or more and 500 or less, and particularly preferably 200 or more and 400 or less. By setting the ratio of the tensile storage elastic modulus at 23 ° C. before and after UV irradiation to the above value, the balance between the development of adhesive strength before UV irradiation and the preservation of evidence after UV irradiation is further improved. it can.

The pressure-sensitive adhesive layer before UV curing is in the range where the ratio of the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 after UV irradiation at 23 ° C. / the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 before UV irradiation at 23 ° C. is 3 or more. The tensile storage elastic modulus E'at 23 ° C. of 2 is preferably 0.1 MPa or more and 10 MPa or less, more preferably 0.5 MPa or more and 5 MPa or less, and further preferably 1 MPa or more and 3 MPa or less. The tensile storage elastic modulus E'at 23 ° C. of the pressure-sensitive adhesive layer after UV curing is preferably 10 MPa or more and 2000 MPa or less, more preferably 30 MPa or more and 1000 MPa or less, and further preferably 100 MPa or more and 500 MPa or less. When the tensile storage elastic modulus E'at 23 ° C. before and after UV irradiation is the above value, the balance between the development of adhesive force before UV irradiation and the preservation of evidence after UV irradiation is further improved. it can.

The value of the tensile storage elastic modulus of the pressure-sensitive adhesive layer 2 at 23 ° C. can be obtained by the method described in Examples.

Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 2 include those containing a pressure-sensitive acrylic polymer and an ultraviolet-polymerizable compound, and those containing a pressure-sensitive acrylic polymer having an ultraviolet-polymerizable group in the side chain.

Examples of the ultraviolet polymerizable compound include a monomer or an oligomer having an ultraviolet polymerizable group.

The ultraviolet polymerizable group is a group having a carbon-carbon double bond, and specific examples thereof include a (meth) acryloyl group and a vinyl group, and a (meth) acryloyl group is preferable in that it has high ultraviolet polymerizable properties. ..

Examples of the monomer having an ultraviolet polymerizable group include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaeristoltetra (meth) acrylate, and dipentaeristol mono. Examples thereof include hydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 1,4-butanediol di (meth) acrylate.

Examples of the oligomer having an ultraviolet polymerizable group include urethane acrylate, polyester acrylate, and epoxy acrylate. The weight average molecular weight of the oligomer is preferably 3000 to 30000.

The content of the monomer or oligomer having an ultraviolet polymerizable group is preferably 10 to 150 parts by mass with respect to 100 parts by mass of the adhesive acrylic polymer. If it is less than 10 parts by mass, the adhesive layer may be deformed while the evidence product is stored. If it is more than 150 parts by mass, the evidence may fall off from the pressure-sensitive adhesive layer.

Examples of the adhesive acrylic polymer include those in which a polymer containing a monomer that imparts adhesiveness, a monomer that imparts cohesive force, a monomer having a crosslinkable functional group, or the like is crosslinked with a crosslinking agent. By combining these components, the adhesive strength before UV curing can be adjusted.

Examples of the monomer that imparts adhesiveness include ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate.

Examples of the monomer that imparts cohesive force include methyl acrylate, methyl methacrylate, styrene, vinyl acetate, and the like.

Examples of the monomer having a crosslinkable functional group include a monomer having a hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 3-hydroxypropyl methacrylate, and a monomer having a carboxyl group such as acrylic acid.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, and metal chelate-based cross-linking agents.

Examples of the isocyanate-based cross-linking agent include biuret bodies such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, isocyanurates, and adducts.

Examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylene diamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane and the like.

Examples of the metal chelate-based cross-linking agent include aluminum trisacetylacetonate and titanium tetraacetylacetonate.

The adhesive acrylic polymer having an ultraviolet polymerizable group can be obtained by a method of introducing an ultraviolet polymerizable group into the adhesive acrylic polymer. For example, a method of adding a compound having an ultraviolet polymerizable group and an isocyanate group to an adhesive acrylic polymer having a hydroxyl group can be mentioned.

Examples of the compound having an ultraviolet polymerizable group and an isocyanate group include 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.

The adhesive acrylic polymer having a hydroxyl group preferably contains 10 to 40 mol% of a monomer having a hydroxyl group.

The compound having an ultraviolet polymerizable group and an isocyanate group is preferably 70 to 90 mol% with respect to the monomer having a hydroxyl group. If it is less than 70 mol%, the tensile elastic modulus after irradiation with ultraviolet rays becomes insufficient, and the adhesive layer may be deformed during storage. If it exceeds 90 mol%, the hydroxyl groups to be crosslinked become insufficient, and the pressure-sensitive adhesive layer may be deformed during storage.

In order for the pressure-sensitive adhesive layer to initiate polymerization by irradiating it with ultraviolet rays, it is preferable that the pressure-sensitive adhesive layer contains a photopolymerization initiator.

Examples of the photopolymerization initiator include 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, and 2, -Hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) Examples thereof include alkylphenone type such as -2-morpholinopropan-1-one, and acylphosphine oxide type such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. When ultraviolet rays are used, the irradiation time and irradiation amount can be reduced by blending a photopolymerization initiator.

The content of the photopolymerization initiator is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the ultraviolet curable polymer. If the content of the photopolymerization initiator is less than the above range, sufficient evidence preservation may not be obtained due to insufficient photopolymerization, and if it exceeds the above range, a residue that does not contribute to photopolymerization is generated, and the pressure-sensitive adhesive layer. Curability may be insufficient.

The adhesive strength of the adhesive layer 2 before irradiation with ultraviolet rays may be such that the adhesive strength of the evidence product 200 can be collected. For example, in accordance with JIS Z0237: 2009, the test piece of the adhesive layer 2 is JIS G. By a test method in which the test piece is affixed to a SUS304 steel plate (test plate) specified in 4305 by roller crimping, and within 30 minutes after the affixing, the test piece is peeled off at 180 ° to the test plate under the condition of a peeling speed of 300 mm / min. The measured adhesive strength may be 0.3 to 3.0 N / 25 mm, 0.5 to 2.5 N / 25 mm, or 0.7 to 2.0 N / 25 mm. Good.

The thickness of the pressure-sensitive adhesive layer 2 is preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 100 μm or less, and further preferably 30 μm or more and 70 μm or less. Here, the thickness of the pressure-sensitive adhesive layer 2 is the average value of the thicknesses measured at 10 randomly selected sites.

<Peeling liner>
The release liner 3 is a sheet material that can be peeled off from the pressure-sensitive adhesive layer 2 and protects the pressure-sensitive adhesive layer 2. Examples of the release liner 3 include a film or paper.

Examples of the film include polyethylene terephthalate and polypropylene, and examples of the paper include high-quality paper, kraft paper, and glassine paper. A film with a smooth surface is preferred for identifying fine evidence.

The release liner 3 is preferably coated with silicone or the like so that it can be peeled off from the pressure-sensitive adhesive layer 2.

The color of the release liner 3 is preferably black so that the evidence product 200 can be clearly distinguished. In the case of a transparent film, black printing may be performed or black paper may be attached to the surface opposite to the surface coated with silicone.

Further, the thickness of the release liner 3 is preferably, for example, 50 μm or more and 250 μm or less in consideration of handleability. Here, the thickness of the release liner 3 is an average value of the thicknesses measured at 10 randomly selected locations.

Further, it is preferable that at least the surface of the release liner 3 on the adhesive layer 2 side has visible light absorption. As a result, the evidence product can be easily visually recognized from the base material 1 side in the stored state.

The visible light absorption rate of the surface of the release liner 3 on the pressure-sensitive adhesive layer 2 side is preferably 80% or more and 98% or less, and more preferably 90% or more and 97% or less. As a result, the evidence product can be easily visually recognized from the base material 1 side in the stored state. If the absorption rate of visible light is too low, it tends to be difficult to reliably exert the above effect. On the other hand, if the absorption rate of visible light is too high, it tends to be difficult to select the material for the release liner 3.

Further, the release liner 3 preferably has an ultraviolet shielding property. As a result, it is possible to prevent the pressure-sensitive adhesive layer 2 from being irradiated with ultraviolet rays via the release liner 3 in an unused state. Further, as a method of imparting ultraviolet shielding property to the release liner 3, for example, it is made of a material having ultraviolet shielding property, an ultraviolet absorbing coating or an ultraviolet reflecting coating is applied to the surface, or an ultraviolet absorber is blended. And so on.

<Protective sheet>
A protective sheet 5 is provided on the surface side of the base material 1 opposite to the pressure-sensitive adhesive layer 2. The protective sheet 5 has a function of protecting the base material 1.

The protective sheet 5 has a protective sheet base material 51 and an adhesive layer 52 (second pressure-sensitive adhesive layer), and the pressure-sensitive adhesive layer 52 and the protective sheet base material 51 are laminated in this order from the base material 1 side. It is made up of the body.

The protective sheet base material 51 can have the same structure as the base material 1, but is preferably made of polyethylene terephthalate, polypropylene, or polyethylene. The thickness of the protective sheet base material 51 is not particularly limited, but is preferably 5 μm or more and 300 μm or less, and more preferably 10 μm or more and 100 μm or less.

Examples of the pressure-sensitive adhesive layer 52 include acrylic type, synthetic rubber type, polyurethane type, silicone type and the like, and it is preferable that the pressure-sensitive adhesive layer 52 can be easily peeled off from the base material 1. The thickness of the pressure-sensitive adhesive layer 52 is not particularly limited, but is preferably 5 μm or more and 200 μm or less, and more preferably 10 μm or more and 50 μm or less.

Further, the protective sheet 5 preferably has visible light transmittance. As a result, when the evidence is collected, the evidence can be visually collected through the protective sheet 5, the base material 1, and the pressure-sensitive adhesive layer 2, that is, through the evidence collection sheet 10.

The transmittance of visible light as a whole of the protective sheet 5 is preferably 70% or more and 99% or less, and more preferably 80% or more and 95% or less. As a result, the above effect can be surely exhibited. If the transmittance of visible light is too low, the evidence product tends to be difficult to see through the protective sheet 5, depending on the transmittance of the base material 1 and the pressure-sensitive adhesive layer 2. On the other hand, if the transmittance of visible light is too high, it tends to be difficult to select the constituent materials of the protective sheet base material 51 and the pressure-sensitive adhesive layer 52.

Further, the protective sheet 5 has an ultraviolet shielding property. As a result, even if ultraviolet rays are incident on the evidence collecting sheet 10 from the protective sheet 5 side in an unused state, it is possible to prevent the ultraviolet rays from transmitting through the protective sheet 5. Therefore, it is possible to prevent the pressure-sensitive adhesive layer 2 from being unintentionally cured in an unused state, and it is possible to maintain high evidence-collectability of the pressure-sensitive adhesive layer 2.

Examples of the method of imparting the ultraviolet shielding property to the protective sheet 5 include a method of blending a material having an ultraviolet shielding property with at least one of the protective sheet base material 51 and the pressure-sensitive adhesive layer 52. Examples of the material having an ultraviolet shielding property include an ultraviolet absorber and an ultraviolet reflecting agent.

As the ultraviolet absorber, for example, a compound having a conjugated unsaturated bond, particularly an aromatic compound, can be preferably used.
Thereby, the absorption efficiency of ultraviolet rays can be made more excellent.

Examples of compounds having a conjugated unsaturated bond include benzophenone-based UV absorbers, benzotriazole-based UV absorbers, salicylic acid-based UV absorbers, oxalic acid anilide-based UV absorbers, cyanoacrylate-based UV absorbers, and triazine-based UV absorbers. Absorbents and the like can be mentioned.

Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and 2,2'. -Dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, [2-hydroxy-4- (octyloxy) phenyl] ( Examples thereof include phenyl) methanone and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane.

Examples of the benzotriazole-based ultraviolet absorber include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- ( 2'-Hydroxy-3', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2 -(2'-Hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-amylphenyl) benzotriazole , 2- (2'-Hydroxy-4'-octoxyphenyl) benzotriazole, 2- [2'-hydroxy-3'-(3'', 4'', 5'', 6'', -tetrahydrophthalimide Methyl) -5'-methylphenyl] benzotriazole, 2,2'methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-yl) phenol], 2 -(2H-benzotriazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2,2'-methylenebis [6- (2H-benzotriazole-2-yl) -4 -(1,1,3,3-tetramethylbutyl) phenol], 2- (2H-benzotriazole-2-yl) -p-cresol, 2- (5-chloro-2H-benzotriazole-2-yl) Examples thereof include -6-tert-butyl-4-methylphenol, [2 (2'-hydroxy-5'-metaacryloxyphenyl) -2H-benzotriazole and the like.

Examples of the salicylic acid-based ultraviolet absorber include phenylsalicylate, p-tert-butylphenylsalicylate, p-octylphenylsalicylate and the like.

Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, ethyl-2-cyano-3,3'-diphenylacrylate and the like.

Examples of the triazine-based ultraviolet absorber include 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 2,4,6- Tris (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris [2-hydroxy-4- (3-butoxy-2-hydroxypropyloxy) phenyl] -1 , 3,5-Triazine, 2,4,6-tris (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine and the like.

Further, as the ultraviolet absorber, for example, an inorganic material such as titania can be used. Inorganic materials (particularly Titania) are particularly excellent in chemical stability and the like, and can exhibit a function of absorbing ultraviolet rays more stably for a longer period of time.

When an ultraviolet absorber (a material having an ultraviolet shielding property) is contained in the protective sheet base material 51, the adhesive layer 52 is prevented from being deteriorated by ultraviolet rays (adhesive strength is lowered), and the ultraviolet absorber is used as a base. It is possible to prevent the material 1 from adhering to the surface of the material 1 and reducing the visibility. When the ultraviolet absorber is contained in the protective sheet base material 51, the content of the ultraviolet absorber contained in the protective sheet base material 51 is not particularly limited, but is 0.1 part by mass or more and 5 parts by mass or less. It is preferably present, and more preferably 0.3 parts by mass or more and 3 parts by mass or less.

If the content of the ultraviolet absorber is too low, the effect of including the ultraviolet absorber as described above may not be sufficiently exhibited depending on the type of the ultraviolet absorber and the like. Further, if the content of the ultraviolet absorber is too high, the content of the material constituting the base material 1 may be relatively lowered, and the adhesion between the base material 1 and the pressure-sensitive adhesive layer 2 may be lowered.

On the other hand, the ultraviolet absorber (material having an ultraviolet shielding property) may be contained in the pressure-sensitive adhesive layer 52. When the ultraviolet absorber is contained in the pressure-sensitive adhesive layer 52, the content of the ultraviolet absorber contained in the pressure-sensitive adhesive layer 52 is not particularly limited, but is preferably 0.1 part by mass or more and 5 parts by mass or less. , 0.3 parts by mass or more and 3 parts by mass or less is more preferable.

If the content of the ultraviolet absorber is too low, the effect of including the ultraviolet absorber as described above may not be sufficiently exhibited depending on the type of the ultraviolet absorber and the like. Further, if the content of the ultraviolet absorber is too high, the content of the pressure-sensitive adhesive may be relatively low, and the function of the pressure-sensitive adhesive may not be fully exhibited.

When the ultraviolet absorber is contained in both the protective sheet base material 51 and the pressure-sensitive adhesive layer 52, the ultraviolet absorber contained in the protective sheet base material 51 and the ultraviolet absorber contained in the pressure-sensitive adhesive layer 52 are combined. The content can be suppressed. Therefore, it is possible to prevent the adhesion between the base material 1 and the pressure-sensitive adhesive layer 2 from being lowered, and it is possible to sufficiently exert the function of the pressure-sensitive adhesive layer 2 as a pressure-sensitive adhesive.

When the ultraviolet absorber is contained in both the protective sheet base material 51 and the pressure-sensitive adhesive layer 52, the content of the ultraviolet absorber contained in the protective sheet base material 51 is not particularly limited, but the pressure-sensitive adhesive is 100% by mass. It is preferably 0.1 part by mass or more and 5 parts by mass or less, and more preferably 0.15 parts by mass or more and 1.5 parts by mass or less. The content of the ultraviolet absorber contained in the pressure-sensitive adhesive layer 52 is not particularly limited, but is preferably 0.1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the pressure-sensitive adhesive. More preferably, it is 1.5 parts by mass or more. As a result, the function of the pressure-sensitive adhesive layer 2 can be sufficiently enhanced while improving the adhesion between the base material 1 and the pressure-sensitive adhesive layer 2.

The ultraviolet transmittance of the entire protective sheet 5 is preferably 0% or more and 15% or less, and more preferably 0% or more and 10% or less. As a result, it is possible to effectively prevent or suppress the irradiation of the pressure-sensitive adhesive layer 2 with ultraviolet rays. If the transmittance is too high, the pressure-sensitive adhesive layer 2 may be unintentionally cured by ultraviolet rays.

As described above, according to the evidence collecting sheet 10, since the protective sheet 5 has an ultraviolet shielding property, the adhesive layer 2 is irradiated with ultraviolet rays through the base material 1 in an unused state. Can be prevented or suppressed. Therefore, it is possible to prevent the pressure-sensitive adhesive layer 2 from being unintentionally cured by ultraviolet rays. As a result, when the evidence product is collected, the adhesive strength of the pressure-sensitive adhesive layer 2 can be surely maintained.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto.

For example, the evidence-collecting sheet may have at least one intermediate layer between the base material and the pressure-sensitive adhesive layer. As the intermediate layer, for example, a layer having an adhesive force enhancing layer (primer layer or the like) or the like may be provided.

The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to these examples. In the following description, the treatments that do not particularly indicate the temperature conditions are performed at room temperature (23 ° C.) and relative humidity of 50%. Further, among various measurement conditions, those showing no particular temperature condition are numerical values at room temperature (23 ° C.) and relative humidity of 50%.

[1] Preparation of Evidence Collection Sheet (Example 1)
First, 2-methacryloyloxyethyl isocyanate (2-hydroxy) was added to an adhesive acrylic polymer (weight average molecular weight 800,000) obtained by polymerizing 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (molar ratio 80:20). By adding 80 mol) to 100 mol of ethyl acrylate, a toluene solution of a tacky acrylic polymer having an ultraviolet polymerizable group was obtained.

By adding 3 parts by mass of 1-hydroxycyclohexylphenyl ketone as a photopolymerization initiator and 4 parts by mass of an adduct of tolylene diisocyanate as a cross-linking agent to 100 parts by mass of the adhesive acrylic polymer of the solution and mixing them. , The first pressure-sensitive adhesive composition was obtained.

Then, the first pressure-sensitive adhesive composition is applied to the surface of the release liner so that the thickness after drying is 36 μm, heated at 90 ° C. for 1 minute, and dried to obtain the first pressure-sensitive adhesive layer. It was. The obtained first pressure-sensitive adhesive layer had ultraviolet curability.

Then, a polyethylene terephthalate film having a thickness of 50 μm, one of which has been treated with silicone, is attached to the first pressure-sensitive adhesive layer so that the side not treated with silicone is located on the side of the first pressure-sensitive adhesive layer. The pressure-sensitive adhesive was isocyanate-crosslinked at ° C. in a 50% RH environment to obtain a laminate.

Next, 100 parts by mass of the adhesive acrylic polymer having a weight average molecular weight of 800,000 and 0.1 parts by mass of 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane as an epoxy-based cross-linking agent. And toluene as a solvent were mixed to prepare a second pressure-sensitive adhesive composition as a coating liquid.

The thickness of the second pressure-sensitive adhesive composition after drying on the surface (silicone-treated surface) of the base material of the laminate of the base material, the first pressure-sensitive adhesive layer and the release liner, using a knife coater. A second pressure-sensitive adhesive layer was obtained by coating so that the thickness was 25 μm.

Next, 1,4-bis (4-benzoyl-3-hydroxyphenoxy) -butane as an ultraviolet absorber and polyethylene terephthalate are kneaded and molded into a film having a thickness of 50 μm to prepare a protective sheet base material. Obtained. Then, the protective sheet base material was attached to the second pressure-sensitive adhesive layer and aged for one week under the conditions of a temperature of 23 ° C. and a relative humidity of 50% to obtain a sheet for collecting evidence of Example 1. The film thickness was measured with a micro gauge.

(Example 2)
First, 2-methacryloyloxyethyl isocyanate (2-hydroxy) was added to an adhesive acrylic polymer (weight average molecular weight 800,000) obtained by polymerizing 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (molar ratio 80:20). By adding 80 mol) to 100 mol of ethyl acrylate, a toluene solution of a tacky acrylic polymer having an ultraviolet polymerizable group was obtained.

To 100 parts by mass of the adhesive acrylic polymer having an ultraviolet polymerizable group of the solution, 3 parts by mass of 1-hydroxycyclohexylphenylketone as a photopolymerization initiator and 4 parts by mass of an adduct of tolylene diisocyanate as a cross-linking agent were added. And mixed to obtain a first pressure-sensitive adhesive composition.

Then, the first pressure-sensitive adhesive composition is applied to the surface of the release liner so that the thickness after drying is 36 μm, heated at 90 ° C. for 1 minute, dried and cured, and the first pressure-sensitive adhesive layer. Got

Then, a polyethylene terephthalate film having a thickness of 50 μm, one of which has been treated with silicone, is attached to the first pressure-sensitive adhesive layer so that the side not treated with silicone is located on the side of the first pressure-sensitive adhesive layer. The pressure-sensitive adhesive was isocyanate-crosslinked at ° C. in a 50% RH environment to obtain a laminate. The obtained first pressure-sensitive adhesive layer has ultraviolet curability.

Next, 100 parts by mass of the adhesive acrylic polymer having a weight average molecular weight of 800,000 and 0.1 parts by mass of 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane as an epoxy-based cross-linking agent. And 3 parts by mass of C7-C9-alkyl-3- [3- (2H-benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4-hydroxyphenyl] propion ether as an ultraviolet absorber. And toluene as a solvent were mixed to prepare a second pressure-sensitive adhesive composition as a coating liquid.

The thickness of the second pressure-sensitive adhesive composition after drying on the surface (silicone-treated surface) of the base material of the laminate of the base material, the first pressure-sensitive adhesive layer and the release liner, using a knife coater. A second pressure-sensitive adhesive layer was obtained by coating so that the thickness was 25 μm.

Next, a protective sheet base material composed of a polyethylene terephthalate film having a thickness of 50 μm was attached to a second pressure-sensitive adhesive layer and aged for one week at a temperature of 23 ° C. and a relative humidity of 50%. A sheet for collecting evidence of Example 2 was obtained. The film thickness was measured with a micro gauge.

(Comparative Example 1)
A sheet for collecting evidence was produced in the same manner as in Example 1 except that the ultraviolet absorber of the second pressure-sensitive adhesive layer was omitted.

In Table 1, 1,4-bis (4-benzoyl-3-hydroxyphenoxy) -butane, which is a photopolymerization initiator of Examples 1 and 2 and Comparative Example 1, is indicated by A1 and compared with Example 1. 2-Methacryloyloxyethyl isocyanate (80 mol with respect to 100 mol of 2-hydroxyethyl acrylate), which is the ultraviolet absorber of Example 1, is indicated by U1 and C7-C9-alkyl-3-, which is the ultraviolet absorber of Example 2. [3- (2H-Benzotriazole-2-yl) -5- (1,1-dimethylethyl) -4-hydroxyphenyl] Propion ether is shown by U2, and the first example of Examples 1 and 2 and Comparative Example 1 is shown. The resin material used to form the pressure-sensitive adhesive layer is indicated by M1, and the resin material used to form the second pressure-sensitive adhesive layer of Examples 1 and 2 and Comparative Example 1 is indicated by M2. 2. The first release liner of Comparative Example 1 is shown by L1.

[2] Evaluation (1) Measurement of Adhesive Strength Before UV Irradiation In accordance with JIS Z0237: 2009, test pieces of each Example and Comparative Example were prepared, the release liner was peeled off, and the SUS304 steel plate specified in JIS G 4305 was prepared. Each Example and Comparative Example by a test method in which the test piece is affixed to (test plate) by roller crimping, and the test piece is peeled off at 180 ° with respect to the test plate within 30 minutes after the affixing under the condition of a peeling speed of 300 mm / min. The adhesive strength of the test piece was measured.

(2) Measurement of Adhesive Strength after UV Irradiation In addition, the sheet for collecting evidence of each Example and Comparative Example was irradiated with UV light from the protective sheet side with a high-pressure mercury lamp (peak illuminance 200 mW / cm ² , integrated light intensity 200 mJ / cm ^2). ) Was performed. Then, in accordance with JIS Z0237: 2009, test pieces of each Example and Comparative Example were prepared, the release liner was peeled off, and the SUS304 steel plate (test plate) specified in JIS G 4305 was roller-bonded and attached. Within 30 minutes from the above, the adhesive strength of the test pieces of each Example and Comparative Example was measured by a test method in which the test piece was peeled off at 180 ° with respect to the test plate under the condition of a peeling speed of 300 mm / min.

The evidence-collecting sheets of Examples 1 and 2 were compared with the evidence-collecting sheets of Comparative Example 1, and the result was that the decrease in adhesive strength after ultraviolet irradiation was prevented. Therefore, the evidence collecting sheets of Examples 1 and 2 have the same or better evidence collecting property as the conventional product.

10 Evidence collection sheet 1 Base material 2 Adhesive layer 3 Release liner 5 Protective sheet 51 Protective sheet base material 52 Adhesive layer 200 Evidence product

Claims (7)

With the base material
A first pressure-sensitive adhesive layer provided on one surface side of the base material and containing a material having ultraviolet curability,
On the other surface side of the base material, a removable protective sheet having an ultraviolet shielding property and
A sheet for collecting evidence, which is provided on the surface side of the first pressure-sensitive adhesive layer opposite to the surface facing the base material, and includes a release liner that protects the first pressure-sensitive adhesive layer. The protective sheet has a protective sheet base material and a second pressure-sensitive adhesive layer in contact with the base material.
The evidence-collecting sheet according to claim 1, wherein the material having an ultraviolet shielding property is contained in the base material. The protective sheet has a protective sheet base material and a second pressure-sensitive adhesive layer in contact with the base material.
The evidence-collecting sheet according to claim 1 or 2, wherein the material having an ultraviolet shielding property is contained in the second pressure-sensitive adhesive layer. The evidence-collecting sheet according to any one of claims 1 to 3, wherein the protective sheet has visible light transmittance. The evidence collecting sheet according to any one of claims 1 to 4, wherein the material having an ultraviolet shielding property is at least one of a triazine compound, a benzotriazole compound and a benzophenone compound. The evidence-collecting sheet according to any one of claims 1 to 5, wherein the release liner has visible light absorption. The evidence-collecting sheet according to any one of claims 1 to 6, wherein the release liner has an ultraviolet shielding property.

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