JPWO2016031072A1 - Pressure sensitive adhesive composition, marking film and retroreflective sheet - Google Patents

Abstract

Pressure-sensitive adhesive composition capable of adhering well to difficult-to-adhere materials and effectively hiding the surface of these materials, and pressure-sensitive formed from such pressure-sensitive adhesive compositions A marking film and a retroreflective sheet including an adhesive layer are provided. The pressure-sensitive adhesive composition according to an embodiment of the present disclosure is derived from (a) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower, and (b) an aromatic vinyl monomer. Derived from a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit, (c) a tackifier, (d) the carboxyl group-containing adhesive (meth) acrylic polymer, and an aromatic vinyl monomer 15 parts by mass or more of a titanium dioxide pigment with respect to a total of 100 parts by mass of the dispersant and tackifier containing an amino group-containing (meth) acrylic polymer that does not contain the monomer unit.

Description

  The present disclosure relates to a pressure-sensitive adhesive composition having a concealing property and suitable for adhesion of a hardly-adhesive material, and a marking film and a retroreflective sheet including a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition About.

  In vehicles, buildings, traffic signs, packaging materials, signs, etc., decorative or functional films or sheets such as marking films with a pressure-sensitive adhesive layer provided on a film base or retroreflective sheets are used. . These films or sheets require the ability to conceal the color (background color) or pattern on the surface of the adherend in order to appropriately exhibit decorativeness, retroreflective properties, and the like.

  As a means for imparting concealability to the marking film and the retroreflective sheet, use of an adhesive layer or a pressure-sensitive adhesive layer containing a white pigment such as titanium dioxide can be mentioned.

  Patent Document 1 (Patent No. 5296335) states that “a carboxyl group-containing (meth) acrylic adhesive polymer, and a pigment or dye, and a colorant comprising an amino group-containing (meth) acrylic polymer that does not contain an aromatic vinyl monomer”. Including an acrylic colored pressure-sensitive adhesive in which the content of the amino group-containing (meth) acrylic polymer that does not contain the aromatic vinyl monomer is 5 to 1000 parts by mass with respect to 1 to 100 parts by mass of the pigment or dye. ing.

  Patent Document 2 (Japanese Patent No. 3500240) states that “in a colored film in which at least one colored adhesive layer is provided on one surface of a transparent film, the adhesive layer is a color composed of a pigment and a dispersant. The dispersing agent has an ammonium group quaternized with an aromatic vinyl monomer, a primary to tertiary amino group-containing (meth) acrylic acid ester monomer, and an aromatic compound as a monomer component (meth). "Colored film comprising a (meth) acrylic acid ester polymer having an acrylic acid ester monomer as an essential component" is described.

  Patent Document 3 (Patent No. 43079797) states that “a white toner is prepared by uniformly dispersing a white pigment and a polyester plasticizer having a glass transition temperature of −10 ° C. or less, and this white toner and an adhesive are mixed. A white pressure-sensitive adhesive layer containing 3 to 150 parts by weight of a white pigment with respect to 100 parts by weight of the pressure-sensitive adhesive on one side of a colored film having a total light transmittance of 3 to 80% by the obtained white pressure-sensitive adhesive composition The manufacturing method of the adhesive sheet for decoration characterized by forming "is described.

  Patent Document 4 (Patent No. 3516035) states that “(meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms as a main component, a carboxyl group contained therein, and a copolymerizable unsaturated monomer. A resin composition (1) having a weight average molecular weight of 800,000 or more obtained by copolymerization of 0.5 to 10% by weight, and a methacrylic acid alkyl ester or methacrylic acid cycloalkyl ester having 1 to 20 carbon atoms in the alkyl group 1 or 2 or more types of monomers selected from benzyl methacrylate or styrene as a main component, containing 0.5 to 10% by weight of a copolymerizable unsaturated monomer containing an amino group and copolymerizable thereto. The obtained resin composition (2) having a glass transition temperature (Tg) of 40 ° C. or more and a weight average molecular weight of 100,000 or less, and 100 parts by weight of the resin composition (1) It describes a resin composition (2) 1 to 40 parts by weight of the adhesive composition prepared by adding ".

Japanese Patent No. 5296335 Japanese Patent No. 3500240 Japanese Patent No. 43079797 Japanese Patent No. 3516035

  Polyolefin resins such as polyethylene (PE) and polypropylene (PP) that are lightweight, inexpensive, and do not contain halogen are difficult to adhere because of their low surface energy. In particular, polypropylene resins are suitable for outdoor applications such as automotive exterior parts and traffic signs in terms of strength, moldability, weather resistance, etc., but are known to be particularly difficult to bond with pressure sensitive adhesives. Yes.

  Adhesion to inorganic materials such as mortar used for building outer walls is often constrained by the low smoothness of the material surface, which limits the choice and use of pressure-sensitive adhesives to achieve good adhesion. May be.

  The purpose of the present disclosure is to make it possible to adhere well to difficult-to-adhere materials such as polyolefin resins such as polyethylene and polypropylene, and inorganic materials such as mortar, and to effectively conceal the surface of these materials. It is to provide a pressure-sensitive adhesive composition. Another object of the present disclosure is to provide a marking film and a retroreflective sheet comprising a pressure sensitive adhesive layer formed from such a pressure sensitive adhesive composition.

  According to one embodiment of the present disclosure, (a) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower and (b) a monomer unit derived from an aromatic vinyl monomer are not included. A dispersant containing an amino group-containing (meth) acrylic polymer, and (c) a rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic At least one tackifier selected from the group consisting of a group-modified terpene resin, and (d) an amino group containing no monomer unit derived from the carboxyl group-containing tacky (meth) acrylic polymer or aromatic vinyl monomer 15 parts by mass or more of titanium dioxide with respect to 100 parts by mass in total of the dispersant and tackifier containing the (meth) acrylic polymer The pressure sensitive adhesive composition containing a pigment is provided.

  According to another embodiment of the present disclosure, a marking film comprising a base film layer and a pressure sensitive adhesive layer disposed on or above the base film layer, wherein the pressure sensitive adhesive layer comprises: Dispersant comprising a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower, and (b) an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer And (c) at least one selected from the group consisting of rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin. Monomers derived from two tackifiers, (d) the carboxyl group-containing tacky (meth) acrylic polymer, and aromatic vinyl monomer Position and a titanium dioxide pigment to 15 parts by weight of the amino group-containing (meth) total 100 parts by weight of dispersants and tackifier comprises an acrylic polymer without, marking film is provided.

  According to still another embodiment of the present disclosure, a retroreflective sheet including a retroreflective layer including a cube corner element, and a pressure-sensitive adhesive layer disposed on or above the cube corner element, The pressure-sensitive adhesive layer comprises (a) a carboxyl group-containing tacky (meth) acrylic polymer having a glass transition temperature of −50 ° C. or less, and (b) an amino group containing no monomer unit derived from an aromatic vinyl monomer ( (C) rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin At least one tackifier selected from the group consisting of: (d) the carboxyl group-containing tacky (meth) acrylic polymer; A retroreflective sheet comprising 15 parts by mass or more of a titanium dioxide pigment with respect to a total of 100 parts by mass of a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from a monomer and a tackifier Is provided.

  The pressure-sensitive adhesive composition of the present disclosure adheres well to difficult-to-adhere materials such as polyolefin resins such as polyethylene and polypropylene, and inorganic materials such as mortar, and effectively conceals the surface of these materials. be able to. Even if the marking film and the retroreflective sheet including the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present disclosure are applied to an adherend formed from a difficult-to-adhere material, these It is possible to satisfactorily adhere to the adherend and to effectively conceal the color and pattern on the surface of the adherend, thereby sufficiently exhibiting decorative properties, retroreflective properties, and the like.

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

It is sectional drawing of the marking film of one embodiment of this indication. It is sectional drawing of the retroreflection sheet of one embodiment of this indication. It is a photograph which shows the result of the concealment test of Examples 1-4 and Comparative Examples 1-3.

  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, “(meth) acryl” means acryl or methacryl, and “(meth) acrylate” means acrylate or methacrylate.

  In the present disclosure, the term “pressure-sensitive adhesive” refers to a permanent adhesiveness in a use temperature range, for example, in a range of 0 ° C. or more and 50 ° C. or less, and adheres to various surfaces with a light pressure, and phase change (from liquid Means a property of a material or composition that does not exhibit (to solid).

  In the present disclosure, “on” representing the positional relationship between the pressure-sensitive adhesive layer and the base film layer or the cube corner element is a direction along the direction perpendicular to the main surface of the film or sheet, regardless of the direction of gravity. It means that the pressure bonding layer and the base film layer or the cube corner element are located, and at least a part of them is in contact with each other.

  In the present disclosure, “above” indicating the positional relationship between the pressure-sensitive adhesive layer and the base film layer or the cube corner element is a direction along the direction perpendicular to the main surface of the film or sheet, regardless of the direction of gravity. It means that the pressure bonding layer and the base film layer or the cube corner element are located.

  In the present disclosure, “retroreflection” and “retroreflection” mean a phenomenon or characteristic of a material in which light from a light source incident on a material is reflected and reflected in the direction of the light source.

  In the present disclosure, “transparent” means that the average transmittance of light of a target wavelength or wavelength region is about 60% or more, preferably about 80% or more, more preferably about 90% or more.

  The pressure-sensitive adhesive composition according to an embodiment of the present disclosure is derived from (a) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower, and (b) an aromatic vinyl monomer. A dispersant containing an amino group-containing (meth) acrylic polymer that does not contain a monomer unit (hereinafter, also simply referred to as “amino group-containing (meth) acrylic polymer” in the present disclosure), and (c) a rosin ester type, At least one tackifier selected from the group consisting of hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin; (d) And titanium dioxide pigment. The titanium dioxide pigment is a total of 100 masses of a carboxyl group-containing tacky (meth) acrylic polymer, a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer, and a tackifier. The pressure-sensitive adhesive composition is contained in an amount of 15 parts by mass or more with respect to the part.

  It is known to change the adhesion performance by adding a tackifier to a general acrylic pressure sensitive adhesive. On the other hand, the inventors of the present invention are superior to difficult-to-adhere materials such as polyolefin resins by further adding a tackifier to an acrylic pressure-sensitive adhesive containing a large amount of titanium dioxide as a white pigment. It has been found that a pressure-sensitive adhesive having adhesive strength can be obtained. Since pigments such as titanium dioxide are solid, they have a disadvantageous effect on the adhesive strength of pressure-sensitive adhesives, and the tackifier itself does not have adhesive properties. It is expected that the adhesive strength of the pressure sensitive adhesive will be significantly reduced when used together with a tackifier. This surprising result found by the present inventors is contrary to the expectation of those skilled in the art, and extends the use of the acrylic pressure-sensitive adhesive having concealment to adherends of difficult-to-adhere materials. Providing significant technical and economic benefits.

  In the pressure-sensitive adhesive composition of the present disclosure, an amino group-containing (meth) acrylic polymer that does not contain a monomer unit derived from an aromatic vinyl monomer improves the dispersibility of the titanium dioxide pigment. It can be filled into the composition to enhance the hiding properties of the pressure sensitive adhesive. Moreover, the adhesive force and concealment property of a pressure sensitive adhesive can be maintained at a high level by disperse | distributing a titanium dioxide pigment in a pressure sensitive adhesive effectively by amino group containing (meth) acrylic-type polymer.

The carboxyl group-containing adhesive (meth) acrylic polymer is composed mainly of a monoethylenically unsaturated monomer and a monoethylenically unsaturated monomer containing a carboxyl group (carboxyl group-containing monoethylenically unsaturated monomer). It can be obtained by copolymerization. The monoethylenically unsaturated monomer is the main component of the polymer and generally has the formula CH ₂ = CR ¹ COOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is linear or cyclic) Or a branched alkyl group, a phenyl group, an alkoxyalkyl group, a phenoxyalkyl group, a hydroxyalkyl group, or a cyclic ether group.), Styrene, α-methylstyrene, vinyltoluene, etc. Aromatic vinyl monomers, vinyl esters such as vinyl acetate, and unsaturated nitriles such as acrylonitrile and methacrylonitrile are also included. Examples of monoethylenically unsaturated monomers represented by the formula CH ₂ = CR ¹ COOR ² include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isoamyl (meth) acrylate, n- Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. Alkyl (meth) acrylates; phenoxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate; methoxypropyl (meth) acrylate, 2-methoxybutyl (meth) acrylate Alkoxyalkyl (meth) acrylates; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; glycidyl (meth) acrylate, tetrahydro Examples thereof include cyclic ether-containing (meth) acrylates such as furfuryl (meth) acrylate. As the monoethylenically unsaturated monomer, one type or two or more types of monoethylenically unsaturated monomers can be used as necessary.

  As monoethylenically unsaturated monomers containing carboxyl groups, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; unsaturated dicarboxylic acids such as itaconic acid, fumaric acid, citraconic acid and maleic acid; ω-carboxypolycaprolactone Examples include monoacrylate, monohydroxyethyl (meth) acrylate phthalate, β-carboxyethyl acrylate, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and the like.

  The glass transition temperature (Tg) of the carboxyl group-containing tacky (meth) acrylic polymer is about −50 ° C. or less, thereby providing a pressure-sensitive adhesive having good adhesion while containing a large amount of titanium dioxide pigment. can do. In some embodiments, the glass transition temperature (Tg) of the carboxyl group-containing tacky (meth) acrylic polymer is about −52 ° C. or lower, or about −55 ° C. or lower, about −80 ° C. or higher, about − 75 ° C. or higher, or about −70 ° C. or higher. When Tg is lower than these ranges, the cohesive force of the pressure-sensitive adhesive tends to decrease. On the other hand, when Tg is higher than these ranges, the adhesiveness of the pressure-sensitive adhesive tends to decrease.

  The carboxyl group-containing adhesive (meth) acrylic polymer is, for example, about 80 parts by mass or more, about 85 parts by mass or more, or about 90 parts by mass or more, about 99.5 parts by mass or less, about 99 parts by mass of a monoethylenically unsaturated monomer. About 0.5 parts by mass or more, about 1 part by mass or more, or about 5 parts by mass or more, about 20 parts by mass or less, about 20 parts by mass or less, It can be obtained by copolymerization at a ratio of 15 parts by mass or less, or about 10 parts by mass or less.

  The carboxyl group-containing tacky (meth) acrylic polymer has a tack at room temperature (about 25 ° C.) and imparts pressure-sensitive adhesiveness to the pressure-sensitive adhesive. The weight average molecular weight of the carboxyl group-containing adhesive (meth) acrylic polymer is generally about 100,000 or more, about 200,000 or more, or about 300,000 or more, less than about 2,000,000, about 1,000,000. Less than 000, or less than about 800,000. If the molecular weight is too high, the dispersibility of titanium dioxide tends to decrease. The weight average molecular weight in the present disclosure means a molecular weight converted with standard polystyrene by GPC method.

  The carboxyl group-containing tacky (meth) acrylic polymer can be used as a main component of the pressure-sensitive adhesive composition. The compounding amount of the carboxyl group-containing adhesive (meth) acrylic polymer is about 30 parts by mass or more, about 35 parts by mass or more, or about 40 parts by mass or more when the entire pressure-sensitive adhesive composition is 100 parts by mass. , About 88 parts by mass or less, about 75 parts by mass or less, or about 60 parts by mass or less.

  An amino group-containing (meth) acrylic polymer that does not contain a monomer unit derived from an aromatic vinyl monomer and is used as a dispersant in the present disclosure is mainly composed of a monoethylenically unsaturated monomer and an amino group-containing unsaturated monomer. It is obtained by copolymerizing with a saturated monomer and does not contain an aromatic vinyl monomer as a constituent component of the polymer. The amino group-containing (meth) acrylic polymer not only acts as a dispersant for the titanium dioxide pigment, but also interacts with the carboxyl group-containing adhesive (meth) acrylic polymer to increase the cohesive strength of the pressure-sensitive adhesive. It is thought that it contributes to this. The monoethylenically unsaturated monomer is the same as the case of the carboxyl group-containing adhesive (meth) acrylic polymer except for the aromatic vinyl monomer, and one or more monoethylenically unsaturated monomers are selected as necessary. Monomers can be used. The aromatic vinyl monomer includes styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, vinyl anthracene, vinyl anthraquinone, (meth) acrylamide of an aromatic amine, (meth) acrylate of a hydroxyl group-containing aromatic compound, and the like. Aromatic amines include aniline, benzylamine, naphthylamine, aminoanthracene, aminoanthraquinone or derivatives thereof. Examples of the hydroxyl group-containing aromatic compound include a hydroxyl group-containing compound corresponding to the aromatic amine.

  Examples of the amino group-containing unsaturated monomer include dialkylaminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl acrylate (DMAEA) and N, N-dimethylaminoethyl methacrylate (DMAEMA); N, N-dimethylaminopropyl acrylamide ( DMAPAA), dialkylaminoalkyl (meth) acrylamides such as N, N-dimethylaminopropyl methacrylamide; dialkylaminoalkyl vinyl ethers such as N, N-dimethylaminoethyl vinyl ether and N, N-diethylaminoethyl vinyl ether. If necessary, one or more amino group-containing unsaturated monomers can be used.

  The amino group-containing (meth) acrylic polymer is, for example, about 80 parts by mass or more, about 85 parts by mass or more, or about 90 parts by mass or more, about 99.5 parts by mass or less, about 99 parts by mass of a monoethylenically unsaturated monomer. Or about 95 parts by mass or less, and about 0.5 parts by mass or more, about 1 part by mass or more, or about 5 parts by mass or more, about 30 parts by mass or less, about 20 parts by mass or less, Or it can obtain by copolymerizing in the ratio of about 10 mass parts or less.

  The weight average molecular weight of the amino group-containing (meth) acrylic polymer is not particularly limited, and for example, about 1,000 or more, about 5,000 or more, about 10,000 or more, about 500,000 or less, about 200,000 or less. Or about 100,000 or less.

  The compounding amount of the amino group-containing (meth) acrylic polymer is about 2 parts by mass or more, about 4 parts by mass or more, or about 8 parts by mass or more, when the total pressure-sensitive adhesive composition is 100 parts by mass. It can be 25 parts by mass or less, about 20 parts by mass or less, or about 15 parts by mass or less.

  In some embodiments, the glass transition temperature (Tg) of the amino group-containing (meth) acrylic polymer is about 0 ° C. or higher, about 20 ° C. or higher, or about 40 ° C. or higher, about 150 ° C. or lower, about 135 ° C. or lower, Or about 120 degrees C or less.

The glass transition temperature (Tg) of the carboxyl group-containing adhesive (meth) acrylic polymer and the amino group-containing (meth) acrylic polymer is expressed as the FOX formula (wherein each polymer is copolymerized from n types of monomers). It can be obtained from the following formula.

  The copolymerization of these polymers is preferably carried out by radical polymerization, and known polymerization methods such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization can be used. As initiators, organic peroxides such as benzoyl peroxide, lauroyl peroxide, bis (4-tert-butylcyclohexyl) peroxydicarbonate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 -Methylbutyronitrile), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-methylpropionic acid) An azo polymerization initiator such as dimethyl or azobis (2,4-dimethylvaleronitrile) (AVN) can be used. The amount of the initiator used is generally about 0.01 parts by mass or more, or about 0.05 parts by mass or more, about 5 parts by mass or less, or about 3 parts by mass or less with respect to 100 parts by mass of the monomer mixture.

  As the tackifier included in the pressure-sensitive adhesive composition, it is preferable to use a tackifier exhibiting compatibility with at least an acrylic resin. For example, rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, aromatic modified terpene resin and the like can be used. Among them, it is preferable to use a rosin ester tackifier. A tackifier can be used by 1 type or in combination of 2 or more types.

  As a rosin ester, a monohydric alcohol such as methanol or ethanol, or a natural rosin ester that is an esterified product of a polyhydric alcohol such as glycerin or pentaerythritol and a natural rosin (eg, gum rosin, tall oil rosin, wood rosin); Or a modified rosin ester which is an esterified product of a polyhydric alcohol and a modified rosin such as a hydrogenated rosin, a disproportionated rosin or an acid-modified rosin; an ester of the monohydric or polyhydric alcohol and a polymerized rosin (especially a polymerized natural rosin) Polymerized rosin ester which is a compound. Natural rosin, hydrogenated rosin, disproportionated rosin, acid-modified rosin and polymerized rosin may be purified by recrystallization or the like. These rosins are generally used as resin acids as abietic acid, neoabietic acid, dehydroabietic acid, parastrinic acid, levopimaric acid, pimaric acid, isopimaric acid, sandaracopimalic acid, tetrahydroabietic acid, dehydroabietic acid, dihydroabietic acid, Or a mixture thereof.

  In some embodiments, the softening point of the rosin ester is about 70 ° C or higher, about 75 ° C or higher, or about 80 ° C or higher, about 130 ° C or lower, about 120 ° C or lower, or about 110 ° C or lower. By using a rosin ester having a softening point in the above range as a tackifier, it is possible to obtain a pressure-sensitive adhesive having excellent adhesive strength at high temperatures and little change with time in adhesive strength. The softening point of rosin ester can be measured by a thermomechanical analyzer (TMA).

  In some embodiments, the acid value (mg KOH / g) of the rosin ester is about 1 or more, about 2 or more, or about 3 or more, about 45 or less, about 30 or less, or about 20 or less. The acid value of the rosin ester can be determined according to JIS K0070: 1992 (potentiometric titration method).

  In some embodiments, the rosin ester has a color number of about 9 or less, about 5 or less, or about 3 or less. The number of colors of the rosin ester can be determined according to the Gardner colorimetric method (JIS K0071-2).

  Commercially available rosin esters include, for example, Haritac F85 (stabilized rosin ester), Haritac F105 (stabilized rosin ester), Haritac 4851 (modified rosin ester), Harrier Star DS-90 (rosin modified special synthetic resin), Neotor (trademark) G2 (stabilized rosin half ester) (all manufactured by Harima Chemical Group Co., Ltd.), Permalyn ™ 5095, Foral ™ 85-E, Permalyn ™ 6110-E, Foral ™ 105-E (all Also, Eastman Co., Ltd.), Foral (trademark) 3085, Foral (trademark) 85 (all are made by PINOVA), etc. are mentioned.

  The use amount of the tackifier is about 3 parts by mass or more, about 4 parts by mass or more, or about 5 parts by mass or more with respect to 100 parts by mass of the carboxyl group-containing adhesive (meth) acrylic polymer in terms of solid content. It can be about 150 parts by weight or less, about 130 parts by weight or less, or about 110 parts by weight or less.

  The titanium dioxide pigment imparts hiding properties to the pressure sensitive adhesive. While not being bound by any theory, titanium dioxide pigments form intermolecular crosslinks of carboxyl group-containing tacky (meth) acrylic polymers and contribute to increasing the cohesive strength of pressure sensitive adhesives. It is thought that The titanium dioxide pigment may be particles having various shapes such as a spherical shape, a needle shape, a flat shape, or a flake shape, and is preferably a spherical particle because of good dispersibility. The titanium dioxide pigment may be surface-treated with a coupling agent such as silane or titanate in order to further improve dispersibility.

The average primary particle size of the titanium dioxide pigment is generally about 0.10 μm or more, about 0.12 μm or more, or about 0.15 μm or more, about 0.50 μm or less, about 0.40 μm or less, or about 0.30 μm or less. . By setting the average primary particle size of the titanium dioxide pigment within the above range, the titanium dioxide pigment can be more uniformly dispersed in the pressure-sensitive adhesive. The average primary particle size of the titanium dioxide pigment is the volume cumulative particle size D ₅₀ that can be determined using laser diffraction / scattering particle size distribution measurements.

  The compounding amount of the titanium dioxide pigment is such that the carboxyl group-containing adhesive (meth) acrylic polymer, the dispersant and the tackifier containing the amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer. It is about 15 parts by mass or more with respect to 100 parts by mass in total, and thereby sufficient concealability can be imparted to the pressure sensitive adhesive. In some embodiments, the compounding amount of the titanium dioxide pigment includes a carboxyl group-containing adhesive (meth) acrylic polymer, an amino group-containing (meth) acrylic polymer that does not include a monomer unit derived from an aromatic vinyl monomer. About 20 parts by mass or more, about 25 parts by mass or more, or about 30 parts by mass or more, about 150 parts by mass or less, about 120 parts by mass or less, or about 100 parts by mass with respect to 100 parts by mass in total of the dispersant and the tackifier It is as follows.

  The pressure-sensitive adhesive composition may include a colorant composed of a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer, and a titanium dioxide pigment. More titanium dioxide pigment is incorporated into the pressure sensitive adhesive composition by including the titanium dioxide pigment in the pressure sensitive adhesive composition in the form of a colorant, i.e., predispersed in a polymer containing dispersant. It can be dispersed stably.

  The colorant can be obtained by mixing a dispersant and a titanium dioxide pigment by a known method. For the mixing, for example, a paint shaker (manufactured by Sinky Corporation), a sand grind mill, a ball mill, an attritor mill, a three-roll mill, or the like can be used. If necessary, an aqueous solvent or an organic solvent may be used during mixing. Even after a long time (for example, about 1 month) after preparation, the colorant can maintain a well dispersed state without aggregation of the titanium dioxide pigment particles, just after the preparation.

  The amount of the dispersant contained in the colorant may be 100% by mass of the dispersant contained in the pressure-sensitive adhesive composition.

  The amount of the titanium dioxide pigment contained in the colorant may be 100% by mass of the dispersant contained in the pressure-sensitive adhesive composition.

  In the colorant, the blending amount of the titanium dioxide pigment is about 100 parts by mass or more, about 500 parts by mass or more, or about 1000 parts by mass or more, about 10,000 parts by mass or less, about 5000 parts by mass with respect to 100 parts by mass of the dispersant. Or about 2000 parts by mass or less.

  The pressure sensitive adhesive composition may include a crosslinking agent. As a crosslinking agent, for a carboxyl group-containing adhesive (meth) acrylic polymer, for example, a bisamide-based crosslinking agent (for example, 1,1′-isophthaloyl-bis (2-methylaziridine)), an aziridine-based crosslinking agent (for example, Chemitite PZ33 manufactured by Nippon Shokubai Co., Ltd., NeoCryl CX-100 manufactured by Avisia Co., Ltd., carbodiimide-based crosslinking agents (for example, Carbodilite V-03, V-05, V-07 manufactured by Nisshinbo Chemical Co., Ltd.), epoxy-based crosslinking agents (for example, Soken Chemical Co., Ltd. E-AX, E-5XM, E5C), isocyanate cross-linking agent (for example, Nippon Polyurethane Industry Co., Ltd. Coronate L, Coronate HK, Bayer Corp. Death Module H, Death Module W, Death Module I) Etc. can be used. For amino group-containing (meth) acrylic polymers, epoxy crosslinking agents (for example, E-AX, E-5XM, E5C manufactured by Soken Chemical Co., Ltd.), isocyanate crosslinking agents (for example, Coronate manufactured by Nippon Polyurethane Industry Co., Ltd.) L, Coronate HK, Death Module H, Death Module W, Death Module I) manufactured by Bayer, etc. can be used.

  The addition amount of the crosslinking agent is about 0.01 equivalent or more and about 0 with respect to the carboxyl group in the carboxyl group-containing adhesive (meth) acrylic polymer or the amino group in the amino group-containing (meth) acrylic polymer. 0.02 equivalents or more, or about 0.05 equivalents or more, about 0.5 equivalents or less, about 0.3 equivalents or less, or about 0.2 equivalents or less.

  The pressure sensitive adhesive composition includes other white pigments such as zinc carbonate, zinc oxide and zinc sulfide, fillers such as talc, kaolin, calcium carbonate, aluminum flakes, fumed silica, alumina and nanoparticles as other components. , Antioxidants, UV stabilizers and the like.

  The pressure-sensitive adhesive composition comprises a carboxyl group-containing tacky (meth) acrylic polymer, a dispersant containing an amino group-containing (meth) acrylic polymer, a tackifier containing a rosin ester, and a titanium dioxide pigment. It can be obtained by mixing using a known method.

  For example, each component may be put into a mixing container almost simultaneously and mixed using a paint shaker (manufactured by Sinky Co., Ltd.), a sand grind mill, a ball mill, an attritor mill, a three roll mill, or the like. If necessary, an aqueous solvent or an organic solvent may be used during mixing. The titanium dioxide pigment can be mixed with an aqueous solvent or an organic solvent and then mixed with other components.

  As described above, after preparing a colorant by mixing the total amount or part of the dispersant and the total amount or part of the titanium dioxide pigment, the obtained colorant and the remaining components are mixed by a known method, A pressure sensitive adhesive composition can also be prepared.

  The pressure-sensitive adhesive composition of the present disclosure has good adhesion to difficult-to-adhere materials such as polyolefin resins such as polyethylene (PE) and polypropylene (PP) and inorganic materials such as mortar. The material surface can be effectively concealed.

  The marking film of one embodiment of the present disclosure includes a base film layer and a pressure sensitive adhesive layer disposed on or over the base film layer. The pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition of the present disclosure or a crosslinked product after curing. The marking film may have a liner on the surface of the pressure-sensitive adhesive layer opposite to the base film layer.

  A cross-sectional view of a marking film of one embodiment of the present disclosure is shown in FIG. The marking film 10 has a base film layer 14 and a pressure-sensitive adhesive layer 12, and the pressure-sensitive adhesive layer 12 has a liner 16 on the side opposite to the base film layer. Although the base film layer is shown as a transparent material in FIG. 1, the base film layer may be formed of an opaque material or a colored material. As shown in FIG. 1, the base film layer 14 and the pressure-sensitive adhesive layer 12 may be in direct contact, and other layers such as other adhesive layers, colored layers, metal layers, printed layers, A bulk layer or the like may be interposed. Other layers such as other adhesive layers, colored layers, metal layers, printed layers, bulk layers, surface protective film layers, clear layers and the like may be laminated on the base film layer. The marking film may further have another functional layer such as a primer layer.

  As the base film layer, for example, a polyethylene film, a polypropylene film, a polyester film, an acrylic resin film, a polycarbonate film, a polyvinyl chloride film, a polyvinylidene chloride film, a polystyrene film, a polyamide film and the like can be used.

  Examples of the liner that is an optional component include paper; plastic materials such as polyethylene, polypropylene, polyester, and cellulose acetate; paper coated with such plastic materials, and the like. These liners may have a surface subjected to a release treatment with silicone or the like.

  In the marking film, the thickness of each layer is not particularly limited. The thickness of the base film layer can be, for example, about 5 μm or more, about 10 μm or more, or about 20 μm or more, about 300 μm or less, about 200 μm or less, or about 100 μm or less. The thickness of the pressure sensitive adhesive layer can be about 5 μm or more, about 10 μm or more, or about 20 μm or more, about 100 μm or less, about 50 μm or less, or about 30 μm or less. The liner thickness can usually be about 10 μm or more, or about 25 μm or more, about 500 μm or less, or about 200 μm or less.

  The marking film can be produced by a known method. For example, a pressure-sensitive adhesive layer is formed by applying a solution obtained by dissolving a pressure-sensitive adhesive composition in an organic solvent onto a liner by knife coating, bar coating, or the like and drying the solution. A marking film can be formed by laminating a base film layer on the obtained pressure-sensitive adhesive layer by dry lamination or the like.

  The marking film using the pressure-sensitive adhesive composition of the present disclosure is applied to an adherent surface made of a hardly adhesive material such as a polyolefin resin such as polyethylene (PE) or polypropylene (PP), or an inorganic material such as mortar. Since it has good adhesiveness and the covering surface can be effectively concealed, a marking film with high decorativeness can be provided.

  The retroreflective sheet of one embodiment of the present disclosure includes a retroreflective layer including a cube corner element and a pressure-sensitive adhesive layer disposed on or above the cube corner element. The pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition of the present disclosure or a crosslinked product after curing. The retroreflective sheet may have a liner on the surface of the pressure-sensitive adhesive layer opposite to the retroreflective layer.

  A cross-sectional view of a retroreflective sheet according to an embodiment of the present disclosure is shown in FIG. The retroreflective sheet 100 includes a retroreflective layer 110 with a plurality of cube corner elements 112 that collectively form a structured surface 114 opposite the main surface 116. The adhesive layer 130 is adjacent to the retroreflective layer 110. The adhesive layer 130 includes an adhesive 132 and one or more barrier layers 134, and on the opposite side of the retroreflective layer 110, a liner 136 such as a PET film, a polyethylene film, or a laminated paper that has been peeled off with a silicone resin or the like. You may have. The barrier layer 134 has sufficient structural integrity to prevent the adhesive 132 from flowing into the low index layer 138 between the structured surface 114 and the barrier layer 134. The barrier layer 134 may be in direct contact with the tip of the cube corner element 112, may be separated from the tip of the cube corner element 112, or may be slightly pushed into the tip of the cube corner element 112. .

  The barrier layer 134 provides a physical “barrier” between the adhesive 132 and the cube corner element 112, allowing the formation of a low refractive index layer 138. The presence of the barrier layer allows retroreflection of the light ray 150 incident on the portion of the structured surface 114 adjacent to the low index layer 138 and / or the barrier layer 134. The barrier layer 134 can also prevent the adhesive 132 from infiltrating the retroreflective layer 110. An adhesive 132 that does not contact the barrier layer 134 adheres to the cube corner element 112, thereby effectively sealing the retroreflective region and forming an optically active region or cell. The adhesive 132 also holds the retroreflective structure 120 comprised of the retroreflective layer 110 and the adhesive layer 130 together as a whole, thereby eliminating the need for a separate sealing film and sealing process. To do.

  As shown in FIG. 2, the light ray 150 incident on the cube corner element 112 adjacent to the low refractive index layer 138 is retroreflected. In the present disclosure, the region of the retroreflective sheet 100 including the low refractive index layer 138 is an optically active region. In contrast, the region of the retroreflective sheet 100 that does not include the low refractive index layer 138 is an optically inactive region because it does not substantially retroreflect the incident light ray 150 as shown in FIG.

  The low refractive index layer 138 is made of a material having a refractive index of about 1.30 or less, about 1.25 or less, about 1.2 or less, about 1.15 or less, about 1.10 or less, or about 1.05 or less. Including. A typical low refractive index material is air.

  As the material of the barrier layer 134, any material that prevents the adhesive 132 from coming into contact with the cube corner element 112 or entering the low refractive index layer 138 can be used. Typical materials used in the barrier layer include resins, ultraviolet curable polymers, inks, dyes, pigments, inorganic materials, particles, and beads. The dimensions and spacing of the barrier layer may vary. In some embodiments, the barrier layer may form a pattern of grids, stripes, dots, characters, etc. on the retroreflective sheet.

  The thickness of the barrier layer can vary and can generally be about 2 μm or more, or about 3 μm or more, about 10 μm or less, about 8 μm or less, or about 4 μm or less.

  In some embodiments, the adhesive layer 130 includes the pressure sensitive adhesive composition of the present disclosure or a crosslinked product after curing as the adhesive 132. In another embodiment (not shown), the adhesive layer includes a first adhesive layer adjacent to the retroreflective layer and a second layer laminated on the surface of the first adhesive layer opposite to the retroreflective layer. And the first adhesive layer contains other pressure sensitive adhesives such as acrylic pressure sensitive adhesive, natural rubber pressure sensitive adhesive, synthetic rubber pressure sensitive adhesive, silicone pressure sensitive adhesive, etc. The second adhesive layer contains the pressure-sensitive adhesive composition of the present disclosure or a cross-linked product thereof. The other pressure-sensitive adhesive contained in the first adhesive layer may be heat-crosslinked or UV-crosslinked by a crosslinking agent, and if necessary, addition of a tackifier, an antioxidant, an ultraviolet absorber, a plasticizer, etc. An agent may be included. In order to enhance the interlayer adhesion between the first adhesive layer and the second adhesive layer, the surface of the first adhesive layer facing the second adhesive layer and / or the surface of the second adhesive layer facing the first adhesive layer is formed by flame treatment, corona A surface treatment such as a treatment, a plasma treatment, an oxidation with ozone or an oxidizing acid, a sputter etching, or a primer treatment such as polyethylene acrylic acid may be included.

  The thickness of the adhesive layer can vary and can generally be about 30 μm or more, about 40 μm or more, or about 50 μm or more, about 150 μm or less, about 90 μm or less, or about 60 μm or less.

  The retroreflective layer 110 includes any suitable cube corner element 112 that is configured to reflect incident light in a direction back to the light source. The cube corner element 112 may have any suitable structure as long as it exhibits a retroreflecting function. For example, the cube corner element may be a perfect cube, a truncated cube, a cube corner type triangular pyramid, a cube corner type cavity, or the like. For example, the cube corner element includes a trihedral structure having three side surfaces that are substantially orthogonal to each other. In use, the retroreflective sheet 100 is usually arranged with its display surface facing the assumed observer and light source. Light incident on the display surface enters the retroreflective sheet 100 and is reflected by each of the three side surfaces of the cube corner element 112 so as to exit the display surface in a direction substantially toward the light source. In some implementations, the cube corner elements 112 are tilted with respect to each other to improve retroreflective properties over a wider range of incident ray angles. Exemplary embodiments of retroreflective sheets based on cube corners are described in US Pat. Nos. 5,138,488 (Szczech), 5,387,458 (Paverka), and 5,450,235 ( Smith), 5,605,761 (Burns), 5,614,286 (Bacon), 5,691,846 (Benson, Jr.), and 7,422,334. No. (Smith).

  Examples of the material suitably used for the retroreflective layer 110 include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, aliphatic polyurethane, and ethylene copolymer, resins such as ionomers thereof, and inorganic materials such as glass. The cube corner element 112 included in the retroreflective layer 110 can be formed by direct casting on a resin film, for example, as described in US Pat. No. 5,691,846 (Benson, Jr.). it can. When the retroreflective layer is formed by radiation curing, examples of suitable resins include a cured product of a radiation curable composition containing, for example, polyfunctional acrylate, epoxy acrylate, acrylated urethane, and the like. The resin is advantageous for any one or more of, for example, thermal stability, environmental stability, transparency, excellent peelability from a tool or a mold, and adhesion to other layers. A polycarbonate and a cured product of epoxy acrylate are particularly advantageous in terms of thermal stability.

  The thickness of the retroreflective layer can vary and can generally be about 40 μm or more, about 50 μm or more, or about 55 μm or more, about 150 μm or less, about 100 μm or less, or about 60 μm or less. The thickness of the retroreflective layer refers to the distance between the main surface of the retroreflective layer and the highest top of the structured surface. The height of the cube corner element can vary and can generally be about 50 μm or more, about 70 μm or more, or about 80 μm or more, about 150 μm or less, about 120 μm or less, or about 100 μm or less. The height of the cube corner element refers to the length in the direction perpendicular to the surface of the retroreflective sheet, of the area effective for retroreflection of the side surfaces constituting the cube corner element.

  In the method of manufacturing the retroreflective structure 120 having the retroreflective layer 110 and the adhesive layer 130 composed of the barrier layer 134 and the adhesive 132, for example, the material of the barrier layer 134 is disposed on the adhesive 132. And a step of laminating the obtained adhesive layer 130 on the retroreflective layer 110. The adhesive layer 130 can be formed by various methods including, but not limited to, the following representative methods. In one exemplary embodiment, the material forming the barrier layer is printed on the adhesive. The printing method may be a non-contact method, such as printing using an inkjet printer, or a contact printing method, such as flexographic printing. In another exemplary embodiment, the material forming the barrier layer is printed onto a flat release surface, for example using an ink jet or screen printing method, and then transferred from the flat release surface onto the adhesive. In another exemplary embodiment, the material forming the barrier layer is flood coated onto a liner having a microstructured surface and the barrier layer has a microstructured surface by laminating an adhesive thereon. Transferred from the liner to the adhesive.

  The retroreflective sheet may include a transparent polyurethane surface protective layer as the outermost layer. The polyurethane surface protective layer may include a crosslinked product of a polyol having a polyester skeleton or a polycarbonate skeleton and a trifunctional or higher functional aliphatic isocyanate. The retroreflective sheet 100 may include an overlay layer, a graphic layer, a colored layer, etc. as other optional layers or structures.

  The structure of the retroreflective sheet of the present disclosure is not limited to that shown in FIG. 2, and includes, for example, a combination of a cube corner element and a reflection layer, a combination of beads and a reflection layer, and the like. However, it is formed using the pressure-sensitive adhesive composition of the present disclosure on a retroreflective structure that does not have a reflective layer such as a vapor-deposited metal film that is useful for hiding the adherend surface, as shown in FIG. When the pressure-sensitive adhesive layer is used, excellent concealability can be imparted to the retroreflective sheet having such a retroreflective structure.

  The marking film and the retroreflective sheet of the present disclosure can be used for decoration of a vehicle, a building, a traffic sign, a packaging material, a signboard, and the like and a retroreflective function, and the adherend surface is a polyolefin such as polyethylene or polypropylene. This is particularly useful in the case of containing a hard-to-adhere material including inorganic materials such as resin and mortar.

  In the present specification, the following abbreviations shown in Table 1 may be used.

  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.

<Production of dispersant-amino group-containing (meth) acrylic polymer 1 (HAP1)->
60 parts by mass of MMA, 34 parts by mass of BMA, and 6 parts by mass of DMAEMA were dissolved in 150 parts by mass of EtOAc, and dimethyl-2,2-azobis (2-methylpropionate) (trade name V-601, Wako Pure Chemical Industries, Ltd.) as a polymerization initiator. After adding 0.6 parts by mass), the mixture was reacted at 65 ° C. for 24 hours under a nitrogen atmosphere to prepare an EtOAc solution (solid content 40%) of amino group-containing (meth) acrylic polymer 1 (HAP1). . HAP1 had a weight average molecular weight (Mw) of 68,000 and a glass transition temperature (Tg) of 63 ° C. Tg was determined from the FOX formula (the following formula) assuming that each polymer was copolymerized from n types of monomers.

<Production of adhesive polymer 1 (ADH1)>
76 parts by mass of BA, 21 parts by mass of 2EHA, 2 parts by mass of VAc, and 1 part by mass of AA were dissolved in 203 parts by mass of a mixed solvent of toluene / EtOAc (mass ratio 50:50), and 2,2′-azobis (2,2) was used as a polymerization initiator. 4-dimethylvaleronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd.) 0.2 parts by mass was added, followed by reaction at 65 ° C. for 24 hours in a nitrogen atmosphere to obtain adhesive polymer 1 (ADH1). A toluene / EtOAc solution (33% solids) was prepared. ADH1 had a weight average molecular weight (Mw) of 660,000 and a glass transition temperature (Tg) of −57 ° C.

<Manufacture of adhesive polymer 2 (ADH2)>
94 parts by mass of 2EHA, 2 parts by mass of MA, and 4 parts by mass of AA were dissolved in 122 parts by mass of a mixed solvent of toluene / EtOAc (mass ratio 50:50), and 2,2′-azobis (2,4-dimethyl) was used as a polymerization initiator. Valeronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd.) 0.2 parts by mass was added, followed by reaction at 65 ° C. for 24 hours under a nitrogen atmosphere, and toluene / EtOAc of adhesive polymer 2 (ADH2). A solution (45% solids) was prepared. ADH2 had a weight average molecular weight (Mw) of 640,000 and a glass transition temperature (Tg) of −62 ° C.

<Production of adhesive polymer 3 (ADH3)>
94 parts by mass of BA and 6 parts by mass of AA were dissolved in 203 parts by mass of a mixed solvent of toluene / EtOAc (mass ratio 50:50), and 2,2′-azobis (2,4-dimethylvaleronitrile) (as a polymerization initiator) After adding 0.2 parts by mass of trade name V-65 (manufactured by Wako Pure Chemical Industries, Ltd.), the mixture was reacted at 65 ° C. for 24 hours in a nitrogen atmosphere, and a toluene / EtOAc solution of adhesive polymer 3 (ADH3) (solid content) 33%) was prepared. ADH3 had a weight average molecular weight (Mw) of 760,000 and a glass transition temperature (Tg) of −48 ° C.

<Manufacture of adhesive polymer 4 (ADH4)>
94 parts by mass of IOA and 6 parts by mass of AA were dissolved in 122 parts by mass of a mixed solvent of acetone / heptane (mass ratio 50:50), and 2,2′-azobis (2,4-dimethylvaleronitrile) ( After adding 0.2 part by mass of trade name V-65 (manufactured by Wako Pure Chemical Industries, Ltd.), the mixture was reacted at 65 ° C. for 24 hours in a nitrogen atmosphere, and an acetone / heptane solution (solid content) of adhesive polymer 4 (ADH4) 45%) was prepared. ADH4 had a weight average molecular weight (Mw) of 460,000 and a glass transition temperature (Tg) of −49 ° C.

<Production of adhesive polymer 5 (ADH5)>
70 parts by mass of IOA, 22.5 parts by mass of MA, and 7.5 parts by mass of AA were dissolved in 250 parts by mass of EtOAc, and 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name V-65) was used as a polymerization initiator. After adding 0.2 parts by mass of Wako Pure Chemical Industries, Ltd.), the mixture was reacted at 65 ° C. for 24 hours under a nitrogen atmosphere to prepare an EtOAc solution (solid content 40%) of adhesive polymer 5 (ADH5). ADH5 had a weight average molecular weight (Mw) of 360,000 and a glass transition temperature (Tg) of −35 ° C.

  Table 2 shows the polymer composition, crosslinking agent, pigment, and tackifier used in the production of the retroreflective sheet in this example.

<Evaluation method>
The characteristics of the retroreflective sheet were evaluated according to the following method.

1. Initial adhesive force A test piece is prepared by cutting the retroreflective sheet into a length of 150 mm and a width of 25 mm. JIS Z 0237 8.2.3. The test piece is attached to a polypropylene substrate, an aluminum substrate, or a mortar plate smooth surface (manufactured by Nippon Test Panel Co., Ltd.) at 20 ° C. The specimen is left at 20 ° C. for 48 hours. 180 degree | times adhesive force is measured using the tensile tester (Tensilon "Tensilon (trademark)" by Orientec Co., Ltd.) at 20 degreeC. The gripping interval is 100 mm and the peeling speed is 300 mm / min.

2. Adhesion force after curing The retroreflective sheet is cut into a length of 150 mm and a width of 25 mm to prepare a test piece. JIS Z 0237 8.2.3. The test piece is attached to a polypropylene substrate, an aluminum substrate, or a mortar plate smooth surface (manufactured by Nippon Test Panel Co., Ltd.) at 20 ° C. The specimen is left at 650 ° C. for 168 hours. 180 degree | times adhesive force is measured using the tensile tester (Tensilon "Tensilon (trademark)" by Orientec Co., Ltd.) at 20 degreeC. The gripping interval is 100 mm and the peeling speed is 300 mm / min.

  The adhesion to the polypropylene substrate is judged as “good” when the initial and post-curing adhesive strength is 10 N / 25 mm or more, and as “bad” when the initial and post-curing adhesive strength is less than 10 N / 25 mm. The adhesion to the mortar plate is judged as “good” when the initial and post-curing adhesive strength is 10 N / 25 mm or more, and as “bad” when the initial and post-curing adhesive strength is less than 10 N / 25 mm.

3. Concealing property A test piece is prepared by cutting a retroreflective sheet into 50 mm squares. Adhere the test piece to the concealment rate test paper on which white and black portions are printed adjacent to each other. L *, a *, and b * are measured using a spectrocolorimeter (CM-3700A manufactured by Konica Minolta). The equation difference is obtained with the measured values on the white part as L ₁ *, a ₁ *, b ₁ * and the measured values on the black part as L ₂ *, a ₂ *, b ₂ *. The calculation formula of the color difference is as follows, and the concealment property is “excellent” when the color difference is less than 1, “good” when the color difference is 1 or more and less than 3, and “possible” when the color difference is 3 or more and less than 5. If it is 5 or more, it is judged as “bad”.

<Example 1>
Pigment 1, amino group-containing (meth) acrylic polymer 1 (HAP1) and MIBK were mixed to prepare a white pigment dispersion. The mass ratio of Pigment 1 to HAP1 was 5: 1 in terms of solid content. The solid content of the white pigment dispersion solution was about 66%. A white adhesive solution was prepared by mixing a white pigment dispersion solution, an adhesive polymer 1 (ADH1), a tackifier 1 (TF1), and a crosslinking agent 1 (CL1). About the quantity of each component used, ADH1 was 100 mass parts, TF1 was 35 mass parts, HAP1 was 15 mass parts, and the pigment 1 was 75 mass parts. That is, the pigment 1 was 50 mass parts with respect to 100 mass parts in total of ADH1, HAP1, and TF1. CL1 was added to the white adhesive solution. CL1 was 0.05 mass part with respect to 100 mass parts of ADH1. The white adhesive solution was applied on a 50 μm thick polyester film with silicone treatment using a knife coater. The coating layer was dried at 95 ° C. for 5 minutes to obtain a white pressure-sensitive adhesive layer having a thickness of 30 μm. The pressure-sensitive adhesive layer of Disco 2100 (retroreflective sheet with pressure-sensitive adhesive layer, manufactured by 3M) was subjected to corona treatment. The white pressure-sensitive adhesive layer was bonded to the disco 2100 pressure-sensitive adhesive layer to obtain the retroreflective sheet of Example 1.

<Example 2>
The retroreflective sheet of Example 2 was produced in the same manner as in Example 1 except that the amount of CL1 added was changed from 0.05 parts by mass to 0 parts by mass.

<Example 3>
The retroreflective sheet of Example 3 was prepared using the white pigment dispersion solution of Example 1, and the addition amount of pigment 1 was 20 parts by mass with respect to a total of 100 parts by mass of ADH1, HAP1, and TF1, and the addition amount of TF1 was 100. It was produced in the same manner as in Example 1 except that the amounts of ADH1, HAP1, TF1, and pigment 1 were adjusted so as to be 35 parts by mass with respect to parts by mass, and pigment 2 was added. The addition amount of the pigment 2 was 0.5 mass part with respect to 100 mass parts in total of ADH1, HAP1, TF1, and the pigment 1 in conversion of solid content.

<Example 4>
The retroreflective sheet of Example 4 was changed from ADH1 to ADH2 using the white pigment dispersion solution of Example 1, and the amount of pigment 1 added was 50 parts by mass with respect to a total of 100 parts by mass of ADH2, HAP1, and TF1, TF1 This was prepared in the same manner as in Example 1 except that the amounts of ADH2, HAP1, TF1, and pigment 1 were adjusted so that the amount of ADH2 was 30 parts by mass with respect to 100 parts by mass of ADH2.

<Comparative Example 1>
For the retroreflective sheet of Comparative Example 1, the white pigment dispersion solution of Example 1 was used, the addition amount of TF1 was changed from 35 parts by mass to 0 parts by mass, ADH1 was changed to ADH3, and the addition amount of Pigment 1 was ADH3 And the amount of ADH3, HAP1, and the pigment 1 was adjusted so that it might be 50 mass parts with respect to 100 mass parts in total of HAP1, and the addition amount of CL1 was changed from 0.05 mass part to 0.2 mass part Except this, it was produced in the same manner as in Example 1.

<Comparative example 2>
The retroreflective sheet of Comparative Example 2 was prepared by mixing only 100 parts by mass of ADH1, 35 parts by mass of TF1, and 0.05 parts by mass of CL1 without using a white pigment dispersion solution. This was prepared in the same manner as in Example 1 except that this was used in place of the white adhesive solution.

<Comparative Example 3>
The retroreflective sheet of Comparative Example 3 was mixed with only 100 parts by mass of ADH4, 47 parts by mass of TF1, and 19.1 parts by mass of Pigment 1 without using a white pigment dispersion solution to prepare a white adhesive solution. It was produced in the same manner as in Example 1 except that it was prepared.

<Example 5>
The 30 μm thick white pressure-sensitive adhesive layer of Example 1 was bonded to a 50 μm thick transparent acrylic film with a 50 μm thick release-treated polyester film. The marking film of Example 5 was obtained by removing the 50 μm thick release-treated polyester film.

<Example 6>
The marking film of Example 6 was produced in the same manner as Example 5 except that the amount of CL1 added was changed from 0.05 parts by mass to 0 parts by mass in the production of the white pressure-sensitive adhesive layer of Example 1.

<Example 7>
In the production of the white adhesive layer of Example 1, the marking film of Example 7 was used in the white pigment dispersion solution of Example 1, and the amount of pigment 1 added was 20 parts by mass with respect to a total of 100 parts by mass of ADH1, HAP1 and TF1. The amounts of ADH1, HAP1, TF1 and Pigment 1 were adjusted so that the amount of TF1 added was 35 parts by mass with respect to 100 parts by mass of ADH1, and Example 5 was used except that Pigment 2 was added. It produced similarly. The addition amount of the pigment 2 was 0.5 mass part with respect to 100 mass parts in total of ADH1, HAP1, TF1, and the pigment 1 in conversion of solid content.

<Example 8>
In the production of the white pressure-sensitive adhesive layer of Example 1, the marking film of Example 8 was changed from ADH1 to ADH2 using the white pigment dispersion solution of Example 1, and the added amount of pigment 1 was 100 mass in total of ADH2, HAP1 and TF1. Except that the amounts of ADH2, HAP1, TF1, and Pigment 1 were adjusted so that the amount added was 50 parts by weight and TF1 was 30 parts by weight with respect to 100 parts by weight of ADH2, and Example 5 It produced similarly.

<Comparative example 4>
In the production of the white pressure-sensitive adhesive layer of Example 1 for the marking film of Comparative Example 4, the white pigment dispersion solution of Example 1 was used, the amount of TF1 added was changed from 35 parts by weight to 0 parts by weight, and ADH1 was changed to ADH3. The amount of ADH3, HAP1, and Pigment 1 is adjusted so that the amount of Pigment 1 added is 50 parts by mass with respect to the total of 100 parts by mass of ADH3 and HAP1, and the amount of CL1 added is 0.05 parts by mass. This was prepared in the same manner as in Example 5 except that the content was changed from 0.2 to 0.2 parts by mass.

<Comparative Example 5>
In the production of the white adhesive layer of Example 1, the marking film of Comparative Example 5 was prepared using only 100 parts by mass of ADH1, 35 parts by mass of TF1, and 0.05 parts by mass of CL1 without using the white pigment dispersion solution. An adhesive solution was prepared by mixing and was prepared as in Example 5 except that it was used in place of the white adhesive solution.

<Example 9>
In the production of the white pressure-sensitive adhesive layer of Example 1, the marking film of Example 9 was prepared by using the white pigment dispersion solution of Example 1, changing ADH1 to ADH2, and the addition amount of pigment 1 being 100 masses in total of ADH2, HAP1 and TF1. Except that the amounts of ADH2, HAP1, TF1 and Pigment 1 were adjusted so that the amount added was 50 parts by weight with respect to 100 parts by weight and 5 parts by weight with respect to 100 parts by weight of ADH2, respectively. It produced similarly.

<Example 10>
In the production of the white pressure-sensitive adhesive layer of Example 1, the marking film of Example 10 was prepared by using the white pigment dispersion solution of Example 1, changing ADH1 to ADH2, and the addition amount of pigment 1 being 100 masses in total of ADH2, HAP1 and TF1. Except that the amounts of ADH2, HAP1, TF1 and Pigment 1 were adjusted so that the amount added was 50 parts by weight with respect to parts and 20 parts by weight with respect to 100 parts by weight of ADH2, respectively. It produced similarly.

<Example 11>
In the production of the white pressure-sensitive adhesive layer of Example 1, the marking film of Example 11 was changed from ADH1 to ADH2 using the white pigment dispersion solution of Example 1, and the added amount of pigment 1 was 100 mass in total of ADH2, HAP1 and TF1. Except that the amounts of ADH2, HAP1, TF1, and Pigment 1 were adjusted so that the amount added was 50 parts by weight with respect to 100 parts by weight and 50 parts by weight with respect to 100 parts by weight of ADH2, respectively. It produced similarly.

<Example 12>
In the production of the white pressure-sensitive adhesive layer of Example 1, the marking film of Example 12 was changed from ADH1 to ADH2 using the white pigment dispersion solution of Example 1, and the added amount of pigment 1 was a total of 100 masses of ADH2, HAP1 and TF1. Except that the amounts of ADH2, HAP1, TF1 and Pigment 1 were adjusted so that the amount added was 50 parts by weight with respect to 100 parts by weight and 100 parts by weight with respect to 100 parts by weight of ADH2, respectively. It produced similarly.

<Comparative Example 6>
The marking film of Comparative Example 6 was produced in the same manner as in Example 11 except that ADH1 was changed to ADH3.

<Comparative Example 7>
A marking film of Comparative Example 7 was produced in the same manner as in Example 11 except that ADH1 was changed to ADH5.

  The evaluation results of the retroreflective sheets of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 3, and the evaluation results of the marking films of Examples 5 to 12 and Comparative Examples 4 to 7 are shown in Table 4, respectively. Moreover, the result of the concealment test of Examples 1-4 and Comparative Examples 1-3 is shown with a photograph in FIG.

  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 10 Marking film 12 Pressure sensitive adhesive layer 14 Base film layer 16 Liner 100 Retroreflective sheet 110 Retroreflective layer 112 Cube corner element 114 Structured surface 116 Main surface 120 Retroreflective structure 130 Adhesive layer 132 Adhesive 134 Barrier layer 136 Liner 138 Low Refractive Index Layer 150 Light

Claims (13)

(A) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower;
(B) a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer;
(C) At least one adhesive selected from the group consisting of rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin An imparting agent;
(D) A total of 100 parts by mass of the carboxyl group-containing tacky (meth) acrylic polymer, a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer, and a tackifier Pressure sensitive adhesive composition containing 15 parts by mass or more of titanium dioxide pigment.   The pressure sensitive adhesive composition according to claim 1, wherein the tackifier is a rosin ester.   The pressure-sensitive adhesive according to claim 1, comprising 4 to 110 parts by mass of the tackifier based on 100 parts by mass of the carboxyl group-containing adhesive (meth) acrylic polymer. Composition.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, further comprising a crosslinking agent.   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, which is suitable for adhesion of at least one polyolefin resin selected from the group consisting of polyethylene and polypropylene. A marking film comprising a base film layer, and a pressure-sensitive adhesive layer disposed on or above the base film layer, wherein the pressure-sensitive adhesive layer comprises:
(A) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower;
(B) a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer;
(C) At least one adhesive selected from the group consisting of rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin An imparting agent;
(D) A total of 100 parts by mass of the carboxyl group-containing tacky (meth) acrylic polymer, a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer, and a tackifier A marking film comprising 15 parts by mass or more of a titanium dioxide pigment.   The marking film according to claim 6, wherein the tackifier is a rosin ester.   8. The pressure sensitive adhesive layer according to claim 6, wherein the pressure-sensitive adhesive layer contains 4 to 110 parts by mass of the tackifier relative to 100 parts by mass of the carboxyl group-containing tacky (meth) acrylic polymer. Marking film as described in.   At least one of the carboxyl group-containing adhesive (meth) acrylic polymer and the amino group-containing (meth) acrylic polymer that does not contain a monomer unit derived from the aromatic vinyl monomer is crosslinked. The marking film as described in any one of these. A retroreflective layer comprising a cube corner element, and a retroreflective sheet comprising a pressure sensitive adhesive layer disposed on or above the cube corner element, the pressure sensitive adhesive layer comprising:
(A) a carboxyl group-containing adhesive (meth) acrylic polymer having a glass transition temperature of −50 ° C. or lower;
(B) a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer;
(C) At least one adhesive selected from the group consisting of rosin ester, hydrogenated rosin, terpene phenol, styrene, hydrogenated terpene phenol, aromatic modified hydrogenated terpene resin, and aromatic modified terpene resin An imparting agent;
(D) A total of 100 parts by mass of the carboxyl group-containing tacky (meth) acrylic polymer, a dispersant containing an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer, and a tackifier A retroreflective sheet containing 15 parts by mass or more of a titanium dioxide pigment.   The retroreflection sheet according to claim 10, wherein the tackifier is a rosin ester.   The pressure-sensitive adhesive layer according to claim 10 or 11, wherein the tackifier is contained in an amount of 4 parts by mass or more and 110 parts by mass or less with respect to 100 parts by mass of the carboxyl group-containing tacky (meth) acrylic polymer. The retroreflective sheet described in 1.   At least one of the carboxyl group-containing adhesive (meth) acrylic polymer and the amino group-containing (meth) acrylic polymer not containing a monomer unit derived from the aromatic vinyl monomer is crosslinked. The retroreflection sheet according to any one of the above.