JP2009221425A - Adhesive sheet for marking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet for marking which is, in particular, excellent in weatherability and has resistance to rubbing with a chemical, resistance to immersion in a chemical, a desired degree of glossiness, and resistance to cracking when it is elongated and which can be suitably used for e.g. automobiles. <P>SOLUTION: The adhesive sheet for marking has a self-adhesive layer on one surface of a base film, and a crosslinked acryl-urethane coating layer on the other surface of the base film, wherein the coating layer is formed by using a coating agent containing (A) a polyester-modified acrylpolyol resin having a weight-average molecular weight of 15,000-80,000, (B) a polyisocyanate compound, and (C) rutile type titanium oxide particles in an amount of 1-15 pts.mass based on 100 pts.mass of the solid content of the (A) component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive sheet for marking. More specifically, it has excellent weather resistance, chemical scratch resistance, chemical immersion resistance, desired glossiness, crack resistance during stretching, etc. It is related with the adhesive sheet for marking used suitably as.

In recent years, pressure-sensitive adhesive sheets (including pressure-sensitive adhesive tapes; the same applies hereinafter) have been widely used in many fields. For example, for packaging / bundling, office / home use, bonding, paint masking, surface protection, sealing, anticorrosion / waterproofing, electrical insulation, electronic equipment, medical / hygiene materials, display / signs, Used for decoration and labels.
On the other hand, recently, in the field of marking adhesive sheets such as display / labeling adhesive sheets and decorative adhesive sheets among the above-mentioned applications, in order to improve the productivity of coated products and reduce manufacturing costs, it is possible to replace coating. The demand for pressure-sensitive adhesive sheets for use is increasing. For example, danger indication tapes, line tapes, marking tapes, etc. are used for indications / signs. For decoration purposes, signs, show windows and interior / exterior of buildings, decorations for cars and motorcycles with marking sheets / stickers, automobiles Adhesive sheets are used for decorating door sashes.
There are various adherends to which such a coating substitute adhesive sheet is applied, and examples thereof include metal plates, painted metal plates, glass, ceramics, stone materials, wood materials, plastics, papers, and the like.
In adhesive sheets for painting substitutes, the affixed products are often used outdoors, and it is necessary for both the base material and the adhesive to have excellent weather resistance. A system adhesive is used. On the other hand, it is preferable that the base material is excellent in weather resistance, has a small shrinkage rate, and is not very hard from the viewpoint of the workability of application, for example, vinyl chloride resin, polyester, polyolefin, polyacrylate, polycarbonate, polytetrafluoroethylene. A film substrate made of ethylene fluoride, thermoplastic polyurethane or the like is used.
By the way, for marking sheet for marking used in automobiles, in addition to weather resistance, glossiness of the substrate, scratch resistance, chemical immersion resistance (gasoline immersion resistance), etc. are required, but conventional marking In the pressure-sensitive adhesive sheet for use, it was difficult to satisfy these simultaneously.
On the other hand, in the golf ball field, a golf ball coating composition having impact resistance and wear resistance and excellent weather resistance is disclosed (for example, see Patent Document 1). However, this coating composition has insufficient weather resistance because the marking pressure-sensitive adhesive sheet is required to have longer weather resistance than the golf ball.
JP 2003-253201 A

  Under such circumstances, the present invention is particularly excellent in weather resistance, chemical scratch resistance, chemical immersion resistance, desired glossiness, crack resistance during stretching, etc. It aims at providing the adhesive sheet for marking used suitably as.

As a result of intensive research to develop a pressure-sensitive adhesive sheet for marking having the above-mentioned preferable properties, the present inventor found that a specific polyester-modified acrylic polyol resin and a polyisocyanate compound as a curing agent were formed on the surface side of the base film. Preferably, the object can be achieved by a pressure-sensitive adhesive sheet having a cross-linked acrylic urethane-based coating layer containing a specific modified product of the polyisocyanate-based compound and a specific ratio of rutile-type titanium oxide particles. The present invention has been completed based on this finding.
That is, the present invention
[1] While having a pressure-sensitive adhesive layer on one surface of the base film, (A) a polyester-modified acrylic polyol resin having a weight average molecular weight of 15,000 to 80,000 and (B) a polyisocyanate on the other surface Crosslinked acrylic urethane formed using a coating agent containing 1 to 15 parts by mass of (C) rutile-type titanium oxide particles with respect to 100 parts by mass of the solid content of the system compound and component (A) An adhesive sheet for marking, characterized by having a coating layer,
[2] The pressure-sensitive adhesive sheet for marking according to the above [1], wherein the glass transition temperature of the polyester-modified acrylic polyol resin as the component (A) is 42 to 60 ° C.
[3] The marking pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the average particle diameter of the (C) rutile-type titanium oxide particles is 10 to 100 nm,
[4] The polyisocyanate compound as component (B) is an aliphatic, cycloaliphatic, aromatic or araliphatic isocyanate, and adduct-modified, burette-modified, isocyanurate-modified, uretonimine-modified, uretdione. The pressure-sensitive adhesive sheet for marking according to any one of [1] to [3] above, which is at least one selected from a modified body, a carbodiimide-modified body, and an elastically modified polyisocyanate;
[5] Any of [1] to [4] above, wherein the molar ratio [NCO] / [OH] of the isocyanate group of component (B) to the hydroxyl group of component (A) is 0.5 to 1.5. The marking pressure-sensitive adhesive sheet according to any one of [1] to [5] above, wherein the thickness of the marking pressure-sensitive adhesive sheet and [6] cross-linked acrylic urethane coating layer is 1 to 8 μm ,
Is to provide.

  According to the present invention, particularly excellent in weather resistance, chemical scratch resistance, chemical immersion resistance, desired glossiness, crack resistance at the time of stretching, and the like, for example, for marking suitably used for automobiles, etc. An adhesive sheet can be provided.

  The pressure-sensitive adhesive sheet for marking of the present invention has a pressure-sensitive adhesive layer on one surface of a base film, and (A) a polyester-modified acrylic polyol resin having a weight average molecular weight of 15,000 to 80,000 on the other surface; The (B) polyisocyanate compound and the solid content of 100 parts by mass of the component (A) are formed using (C) a coating agent containing 1 to 15 parts by mass of rutile-type titanium oxide particles. It has a cross-linked acrylic urethane coating layer.

[Base film]
As the substrate film used in the pressure-sensitive adhesive sheet for marking according to the present invention, since the pressure-sensitive adhesive sheet is used as a substitute for coating, a film having a small shrinkage rate and not too hard is preferable from the viewpoint of application workability. Therefore, vinyl chloride resins, polyester resins such as polyethylene terephthalate and amorphous polyethylene terephthalate, polyolefin resins such as polyethylene, polypropylene, propylene-ethylene copolymer, acrylic resins, polycarbonate resins, fluorine resins, heat A base film obtained using a plastic urethane-based resin, a polyester-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, a mixture thereof, or the like can be used.

(surface treatment)
These base films are subjected to surface treatment on one or both sides by an oxidation method, an unevenness method, or the like as desired for the purpose of improving the adhesiveness with the pressure-sensitive adhesive layer or acrylic urethane coating layer provided thereon. be able to. Examples of the oxidation method include corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and examples of the unevenness method include a sand blast method, a solvent, and the like. Treatment methods and the like. These surface treatment methods are appropriately selected depending on the type of the substrate, but in general, the corona discharge treatment method is preferably used from the viewpoints of effects and operability. Moreover, what gave the primer process to the single side | surface or both surfaces can also be used.
Although the thickness of this base film is based also on the use of an adhesive sheet, it is normally selected in the range of 10-300 micrometers, Preferably it is the range of 30-200 micrometers.

[Adhesive layer]
In the pressure-sensitive adhesive sheet for marking according to the present invention, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer provided on one surface of the substrate film is not particularly limited, and is conventionally used for the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for marking. Any one can be appropriately selected and used. For example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyurethane adhesive, a polyester adhesive, and the like can be used. These pressure-sensitive adhesives may be emulsion type, solvent type, or solventless type. The thickness of the pressure-sensitive adhesive layer is usually 1 to 300 μm, preferably about 5 to 100 μm.
Among the various pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferable from the viewpoint of weather resistance and the like.

(Acrylic adhesive)
The pressure-sensitive adhesive layer formed using the acrylic pressure-sensitive adhesive includes an acrylic resin having a weight average molecular weight of about 500,000 to 2,000,000, preferably 700,000 to 1,700,000, and is made of a crosslinked acrylic pressure-sensitive adhesive. A layer is preferred. If the weight average molecular weight is in the above range, a marking pressure-sensitive adhesive sheet having a balanced adhesive force and holding force can be obtained.
In addition, the said weight average molecular weight is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

<Acrylic resin>
As the acrylic resin contained in the acrylic pressure-sensitive adhesive, a (meth) acrylic acid ester copolymer is used. As this (meth) acrylic acid ester-based copolymer, an alkyl group in the ester moiety having 1 to 20 carbon atoms (meth) acrylic acid ester, a monomer having a functional group having active hydrogen, and, if desired, Preferred examples include copolymers with other monomers used.
Here, examples of the (meth) acrylic acid ester having 1 to 20 carbon atoms of the alkyl group in the ester portion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth ) Butyl acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, Examples include dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  On the other hand, examples of the monomer having a functional group having active hydrogen include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) (Meth) acrylic acid hydroxyalkyl esters such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; acrylamide, methacrylamide, N-methylacrylamide, N-methyl Acrylamides such as methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide; monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, (meth) acrylic Acids such as monoethylaminopropyl ( Data) acrylate monoalkyl aminoalkyl, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, ethylenically unsaturated carboxylic acids such as citraconic acid. These monomers may be used independently and may be used in combination of 2 or more type.

Examples of other monomers used as desired include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene Styrene monomers such as α-methylstyrene; diene monomers such as butadiene, isoprene and chloroprene; nitrile monomers such as acrylonitrile and methacrylonitrile; N, N-dimethylacrylamide, N, N— And N, N-dialkyl-substituted acrylamides such as dimethylmethacrylamide. These may be used alone or in combination of two or more.
In the acrylic pressure-sensitive adhesive, the (meth) acrylic acid ester copolymer used as a resin component is not particularly limited with respect to the copolymerization form, and may be any of random, block, and graft copolymers. .
In the present invention, this (meth) acrylic acid ester copolymer may be used alone or in combination of two or more.

<Crosslinking agent and other additive components>
The acrylic pressure-sensitive adhesive is preferably subjected to a crosslinking treatment, and the crosslinking agent used for the crosslinking treatment is not particularly limited, and any one of those conventionally used as a crosslinking agent in an acrylic pressure-sensitive adhesive can be arbitrarily selected. Those can be appropriately selected and used. Examples of such a crosslinking agent include polyisocyanate compounds, epoxy compounds, melamine resins, urea resins, dialdehydes, methylol polymers, metal chelate compounds, metal alkoxides, metal salts, and the like. Is preferably used.
In this invention, this crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the amount used depends on the kind of the crosslinking agent, but is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the (meth) acrylic ester copolymer. It is selected in the range of mass parts.
In addition, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, a silane coupling agent, a filler, and the like can be added to the acrylic pressure-sensitive adhesive as desired.

[Coating agent]
In the pressure-sensitive adhesive sheet for marking according to the present invention, the acrylic urethane-based coating layer provided on the surface opposite to the pressure-sensitive adhesive layer of the base film comprises (A) a polyester-modified acrylic polyol resin and (B) a polyisocyanate-based compound. And (C) a crosslinked coating layer formed using a coating agent containing rutile-type titanium oxide particles.
((A) polyester-modified acrylic polyol resin)
In the coating agent, the polyester-modified acrylic polyol resin used as the component (A) is composed of a main chain made of an acrylic polymer and a side chain made of polyester.
In the polyester-modified acrylic polyol resin, the content of the polyester moiety in the side chain is 2 to 50% by mass from the viewpoint of scratch resistance of the coating layer, crack resistance during stretching, stain resistance, weather resistance, and the like. Preferably, 10 to 30% by mass is more preferable.

Moreover, the said polyester modified acrylic polyol resin requires that the weight average molecular weight Mw exists in the range of 15,000-80,000. When the weight average molecular weight is in the above range, chemical scratch resistance, chemical immersion resistance, crack resistance during stretching, and the like are improved. The preferred weight average molecular weight is 16,000-75,000, more preferably 17,000-70,000. Moreover, it is preferable that a glass transition temperature exists in the range of 42-60 degreeC. If this glass transition temperature is in the above range, chemical scratch resistance and the like are good. A more preferable glass transition temperature is 42 to 55 ° C.
The weight average molecular weight is a value in terms of polystyrene measured by the GPC method, and the glass transition temperature is a value measured using a differential scanning calorimeter (DSC) apparatus.
Furthermore, it is preferable that a hydroxyl value exists in the range of 30-180 mgKOH / g. If the hydroxyl value is 30 mgKOH / g or more, sufficient crosslinking is possible, and the coating layer has good chemical scratch resistance and chemical immersion resistance. Moreover, if a hydroxyl value is 180 mgKOH / g or less, the crack resistance at the time of extending | stretching will become favorable. A more preferred hydroxyl value is 50 to 150 mgKOH / g.
The hydroxyl value is a value measured according to JIS K 0070 7.1.

（式中、Ｒ¹、Ｒ²及びＲ³は、それぞれ炭素数１〜１２のアルキレン基、ｎ及びｍは、それぞれ１〜２０の整数を示す。）
で表される構造を有することが好ましい。 The structure of the acrylic polymer that is the main chain of the polyester-modified acrylic polyol resin is not particularly limited, but among all the monomer units constituting the polyester-modified acrylic polyol resin, the repeating units derived from the acrylic monomer described below are included. It is preferable that it is 50 mass% or more. Further, the acrylic monomer constituting the main chain may be only one kind or two or more kinds, and is obtained by copolymerizing with another monomer copolymerizable with the acrylic monomer. It may be.
The polyester part which is the side chain of the polyester-modified acrylic polyol resin has the general formula (I) and / or (II)

(Wherein R ¹ , R ² and R ³ are each an alkylene group having 1 to 12 carbon atoms, and n and m are each an integer of 1 to 20)
It preferably has a structure represented by

The polyester-modified acrylic polyol resin includes, for example, (1) a main chain of an acrylic polymer to which a component constituting a side chain such as a lactone is added, and (2) an acrylic monomer to which a polyester is added (hereinafter, polyester) And a product obtained by homopolymerizing (3) a polyester-containing acrylic monomer and another acrylic monomer.
In the present invention, the polyester-modified acrylic polyol resin is preferably a copolymer composed of at least two kinds of acrylic monomers. The acrylic monomer preferably contains a polyester-containing acrylic monomer.
In the present invention, the amount of the polyester-containing acrylic monomer is preferably 5 to 50% by mass with respect to the total mass of the monomer, from the viewpoint of chemical scratch resistance of the coating layer, crack resistance during stretching, and the like. More preferably, it is 10-30 mass%.

  In the present invention, it is preferable to use a hydroxyl-terminated lactone-modified (meth) acrylate as the polyester-containing acrylic monomer. Examples of the hydroxyl group-terminated lactone-modified (meth) acrylate include those obtained by ring-opening addition of about 1 to 10 mol of a lactone compound to a hydroxyl group-containing acrylic monomer using a catalyst. Examples of the lactone compound include ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, and the like. Specifically, “Placcel FM series (Placcel FM-3 etc.)” (caprolactone-modified methacrylate), “Placcel FA series” (caprolactone-modified acrylate), etc., manufactured by Daicel Chemical Industries, Ltd. can be used.

Other acrylic monomers may be used as the acrylic monomer other than the polyester-containing acrylic monomer, and the type of the acrylic monomer is not particularly limited. For example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert- Butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) Acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, γ-methacryloxypropyltrimethoxysilane, acrylonitrile, acrylamide, N, N-dimethylacrylamide, diacetone acrylate Amide.
Also, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxy Acrylic monomers containing a hydroxyl group such as butyl (meth) acrylate, N-methylol acrylamide, carbonate-modified methacrylate [manufactured by Daicel Chemical Industries, Ltd., "HEMAC"] can also be used.

  In addition to the above polyester-containing acrylic monomer and other acrylic monomers, the polyester-modified acrylic polyol resin may contain an unsaturated monomer copolymerizable with these as a monomer component. Examples of such unsaturated monomers include vinyl ester compounds such as vinyl acetate and vinyl propionate, vinyl ether compounds such as vinyl methyl ether, vinyl cyclohexyl ether, vinyl phenyl ether, vinyl benzyl ether, vinyl glycidyl ether, Ethylenically unsaturated double bond-containing aromatic compounds such as styrene, vinyltoluene and α-methylstyrene, vinyl halides such as vinyl chloride and vinyl bromide, vinylidene halides such as vinylidene chloride and vinylidene bromide, Maleic acid diesters such as dialkyl maleate, fumaric acid diesters such as dialkyl fumarate, itaconic acid diesters such as dimethyl itaconate, heterocyclic vinyl compounds such as N-vinylpyrrolidone and 2-vinylpyridine, allyl alcohol Le, glycerol monoallyl ether, allyl compounds such as glycerol diallyl ether, and the like.

Furthermore, an acrylic monomer having an ultraviolet absorbing unit in the molecule, an acrylic monomer having an antioxidant unit in the molecule, an acrylic monomer having an antistatic unit in the molecule, or the like can be used. By using these acrylic monomers, the coating layer can be provided with good ultraviolet absorbing ability, antioxidant ability, and antistatic ability.
In the present invention, the polyester-modified acrylic polyol resin is composed of a polyester-containing acrylic monomer, a methyl (meth) acrylate, and a (meth) acrylate containing a hydroxyl group, particularly from the viewpoint of crack resistance during stretching and weather resistance. A copolymer is preferable, and a copolymer composed of caprolactone-modified methacrylate, methyl methacrylate and 2-hydroxyethyl methacrylate is particularly preferable.

The polyester-modified acrylic polyol resin uses, for example, the above-mentioned monomers, radical polymerization initiators such as organic peroxide compounds, azo compounds, persulfates, etc., and conventionally known polymerization methods such as solution polymerization methods, suspension weights, etc. It can be produced by a combination method, an emulsion polymerization method or the like.
When the polyester-modified acrylic polyol resin is produced by a solution polymerization method, each of the above monomers is present in a suitable solvent in the presence of a radical polymerization initiator such as an oil-soluble organic peroxide or an azo compound. May be copolymerized.
At this time, examples of the polymerization solvent include known esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as benzene, toluene and xylene, ketones such as acetone, cyclohexanone and methyl ethyl ketone, and ethers such as tetrahydrofuran. A solvent can be used. These solvents can be used alone or in combination of two or more. Although the usage-amount of a polymerization initiator does not have a restriction | limiting in particular, It is about 0.05-2 mass% with respect to the monomer whole quantity.
On the other hand, when the polyester-modified acrylic polyol resin is produced by the emulsion polymerization method, the monomer component is emulsified using an emulsifier as necessary, and a water-soluble organic peroxide, an azo compound, or a persulfate. What is necessary is just to copolymerize in presence of polymerization initiators, such as.
The ester-modified acrylic polyol resin thus obtained needs to have a weight average molecular weight in the range of 15,000 to 80,000. Moreover, it is preferable that a glass transition temperature exists in the range of 42-60 degreeC.

((B) polyisocyanate compound)
In the coating agent, the polyisocyanate compound used as the component (B) is a curing agent for crosslinking the polyester-modified acrylic polyol resin of the component (A) described above to form a crosslinked acrylic urethane-based coating layer. Function.
The polyisocyanate compound is not particularly limited as long as it has two or more isocyanate groups. Specifically, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′- Diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 1,2-phenylene diisocyanate Aromatic diisocyanates such as 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 3,3′-dimethoxydiphenyl-4,4′-diisocyanate, , 6-he Aliphatic diisocyanates such as samethylene diisocyanate, 1,4-tetramethylene diisocyanate, lysine diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate, and the like, Examples thereof include diisocyanates such as alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate. In addition, triisocyanates such as triphenylmethane triisocyanate, methylenebis (4-phenylmethane) triisocyanate, 2,4,6-triisocyanatetoluene, 2,4,4-triisocyanate diphenyl ether, etc., having four isocyanate groups Examples include tetraisocyanates.

In addition, so-called modified polyisocyanates such as adduct-modified products, burette-modified products, isocyanurate-modified products, uretonimine-modified products, uretdione-modified products, carbodiimide-modified products, and elastic-modified polyisocyanates can be used.
The adduct-modified product is a reaction product of a low molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, and the various isocyanates.
The elastically modified polyisocyanate is a diisocyanate such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate as a monomer, and an active hydrogen-containing compound having elasticity thereto is subjected to a urethane reaction. NCO-terminated prepolymer.
Examples of the active hydrogen-containing compound having elasticity used for elastically modifying isocyanates include polyester polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, animal and plant polyols, and copolyols thereof.

In the present invention, as the component (B), the polyisocyanate compound may be used singly or in combination of two or more. Among these, the crack resistance during stretching is From the viewpoint, adduct modified products, isocyanurate modified products and elastic modified polyisocyanates of diisocyanates are preferable.
Further, regarding the blending ratio of the component (A) and the component (B), the molar ratio [NCO] / [OH] of the isocyanate group of the component (B) to the hydroxyl group of the component (A) is 0.5 to 1. A range of 5 is preferable. If the molar ratio is 0.5 or more, the number of unreacted hydroxyl groups is reduced, and the chemical scratch resistance and chemical immersion resistance are improved. On the other hand, if the molar ratio is 1.5 or less, excess isocyanate groups are reduced. Stickiness does not easily remain, and crack resistance during stretching becomes good. [NCO] / [OH] is more preferably 0.8 to 1.2.

((C) Rutile-type titanium oxide particles)
In the coating agent, rutile type titanium oxide particles are blended as the component (C).
Titanium oxide powder has long been known as an ultraviolet scattering agent and has been used in the cosmetic field. In recent years, the photocatalytic activity has attracted attention, and application development has been actively conducted.
Titanium oxide crystals include anatase type, brookite type and rutile type, and the photocatalytic ability is the highest in the anatase type and the lowest in the rutile type. When titanium oxide particles having high photocatalytic ability are contained in the organic coating layer, the organic coating layer is severely deteriorated due to the photocatalytic ability of the titanium oxide particles.
Accordingly, in the pressure-sensitive adhesive sheet for marking according to the present invention, in order to improve the weather resistance, the coating agent contains rutile-type titanium oxide particles having a high ultraviolet scattering ability and the lowest photocatalytic ability.
From the theoretical calculation of the particle size of the titanium oxide and the ultraviolet light scattering ability, it is known that the optimum particle size for UV protection at a wavelength of 300 nm is about 30 to 70 nm, and at a wavelength of 400 nm is about 100 to 150 nm [ J. et al. Coatings Tech. 62 (789), 95 (1990)].
In the present invention, rutile type titanium oxide particles having an average particle size of preferably 10 to 100 nm, more preferably 20 to 70 nm, and still more preferably 20 to 50 nm are used. If the average particle diameter of the rutile-type titanium oxide particles is within the above range, the weather resistance of the resulting pressure-sensitive adhesive sheet for marking is improved. The average particle diameter can be measured by a laser diffraction scattering method.
Moreover, the compounding quantity of this rutile type titanium oxide particle is 1-15 mass parts with respect to 100 mass parts of solid content of the polyester modified acrylic polyol resin of the said (A) component. If the compounding amount of the rutile-type titanium oxide particles is within the above range, the crosslinked acrylic urethane-based coating layer to be formed exhibits sufficient ultraviolet shielding ability and improves the weather resistance of the pressure-sensitive adhesive sheet for marking. , It can suppress that the other performance of this coating layer falls. A preferable compounding quantity is 2-9 mass parts, and a more preferable compounding quantity is 2-7 mass parts.

(Other additive components)
In order to adjust the surface glossiness of the cross-linked acrylic urethane coating layer to be formed, the coating agent includes inorganic particles and / or organic particles having an average particle diameter of about 1 to 5 μm for matting as necessary. Particles can be included.
If the average particle diameter of these particles is in the above range, it has a fine coating surface and can effectively exhibit a matte effect.
Examples of inorganic particles that can be used include silica, alumina, mica, calcium carbonate, barium sulfate, silica sand, and shirasu balloon. Examples of organic particles include polyethylene particles, polystyrene particles, acrylic resin particles, polycarbonate particles, Benzoguanamine / formaldehyde condensate particles, benzoguanamine / melamine / formaldehyde condensate particles, urea resin particles, and wax particles can be used.
In the present invention, these particles may be used alone or in combination of two or more. The content of the matting particles in the cross-linked acrylic urethane coating layer is usually about 0.05 to 10% by mass, preferably 0 in terms of solid content, although it depends on the desired surface gloss. 0.1 to 5% by mass.

(Preparation of coating agent)
The coating agent may be either a solvent type or an emulsion type, but a solvent type is preferred in the present invention.
When the coating agent is a solvent type, the polyester-modified acrylic polyol resin as the component (A), the polyisocyanate compound as the component (B), the rutile-type titanium oxide particles as the component (C), and an appropriate solvent. If necessary, it can be prepared by adding the above-mentioned matting inorganic particles and organic particles and various additives, and uniformly dissolving or dispersing them.
Examples of the solvent include known solvents such as esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as benzene, toluene and xylene, ketones such as acetone, cyclohexanone and methyl ethyl ketone, and ethers such as tetrahydrofuran. can do. These solvents can be used alone or in combination of two or more.
In addition, as various additives, for example, an additive type (low molecular weight type) ultraviolet absorber, antioxidant, antistatic agent, leveling agent, filler, colorant, hydrolysis inhibitor, antifoaming agent and the like are included. Can do.
The concentration suitable for coating is usually about 5 to 50% by mass, preferably 10 to 40% by mass in terms of solid content.

[Coating layer]
In the pressure-sensitive adhesive sheet of the present invention, the cross-linked acrylic urethane-based coating layer formed on the surface opposite to the pressure-sensitive adhesive layer of the base film is prepared by using a conventionally known method such as a bar coating method, Using a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc., it is applied to the surface opposite to the adhesive layer of the base film, and a temperature of about 30 to 80 ° C. for 30 seconds to It can be formed by heating and drying for about 5 minutes.
Although there is no restriction | limiting in particular in the thickness of this crosslinked acrylic urethane type coating layer, Usually, about 1-8 micrometers, Preferably it is 3-6 micrometers.

[Peeling sheet]
In the pressure-sensitive adhesive sheet for marking of the present invention, a release sheet can be attached to the pressure-sensitive adhesive layer. Examples of the release sheet include paper base materials such as glassine paper, coated paper, and high-quality paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, or polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. For example, a film obtained by applying a release agent to a plastic film such as a polyester film such as polypropylene film or a polyethylene film such as polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, a silicone-based material that is inexpensive and provides stable performance is preferable. Although there is no restriction | limiting in particular about the thickness of this peeling sheet, Usually, it is about 20-250 micrometers.
Thus, when sticking a release sheet to an adhesive layer, after applying an adhesive to the release agent layer surface of the release sheet and providing an adhesive layer with a predetermined thickness, this is applied to the base film. The adhesive sheet may be attached to one surface, the pressure-sensitive adhesive layer transferred, and the release sheet attached as it is.

  The pressure-sensitive adhesive sheet for marking according to the present invention is particularly excellent in weather resistance, and has chemical scratch resistance, chemical immersion resistance, crack resistance during stretching, and desired glossiness. Suitable for decoration tapes, line tapes, marking tapes, etc. Also suitable for decoration, interior and exterior of signs, show windows and buildings, decoration of cars and motorcycles with marking sheets and stickers, decoration of automobile door sashes, etc. Used.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The performance of the marking pressure-sensitive adhesive sheet was evaluated according to the following method.
(1) Weather resistance Based on the JIS D 0205 automotive component weather resistance test method, a 5.4 accelerated weather resistance test was conducted and the following evaluation was performed.
7.3 Change in Gloss at 60 ° Specular Gloss (Gloss Residual Ratio γ (%)): 75% or more is acceptable in 2000 hours.
7.4 Discoloration ΔE ^* ab: 2 or less is acceptable in 2000 hours.
7.7 Other Changes in Appearance The accelerated weather resistance test was conducted for 1000 hours and 2000 hours.
(2) Crack resistance Appearance at the time of stretching (presence / absence of crack generation, etc.) was evaluated according to the following evaluation criteria.
In addition, extending | stretching performed the longitudinal direction of the adhesive sheet of 25 mm x 100 mm which peeled the peeling sheet, using Orientec Co., Ltd. "TENSILON RTA-100".
Evaluation criteria ○: No generation of cracks at 10% stretching Δ: No generation of cracks at 5% stretching ×: Generation of cracks at 5% stretching (3) Chemical scuff resistance Isopropyl alcohol (IPA), Using a compounded WAX (WAX) and kerosene impregnated respectively, the surface of the cross-linked acrylic urethane coating layer of the marking adhesive sheet was reciprocated 10 times with a load of 4.9 N. The change rate of the 60 ° specular gloss before and after the test was determined and evaluated according to the following evaluation criteria.
○: Change rate of 60 ° specular gloss is less than 10% before and after the test, and no scratches are found after the test. Δ: Change rate of 60 ° specular gloss is less than 10 to 20% before and after the test, and there is a slight scratch after the test. Enter ×: The rate of change in the 60 ° specular gloss before and after the test is 20% or more, and scratches occur after the test. (4) 60 ° specular gloss Use a gloss meter “VG2000” manufactured by Nippon Denshoku Industries Co., Ltd. The 60 ° specular gloss was measured according to JIS Z 8741.
(5) Chemical immersion resistance At 23 ° C. and 50% RH, a 25 mm × 50 mm adhesive sheet from which the release sheet had been peeled was affixed to a melamine resin coated plate, left in the same environment for 24 hours, and then into gasoline 30 The appearance after immersion for a minute was visually observed and evaluated according to the following criteria.
○: No change in appearance Δ: Slightly cloudy or slight peeling of coating layer ×: Clear appearance abnormality

Moreover, the weight average molecular weight (Mw), glass transition temperature (Tg), and average particle diameter of titanium oxide of the polyester-modified acrylic polyol resin used in each example were measured by the following methods.
<Weight average molecular weight (Mw)>
GPC method Measuring instrument: “HLC-8120” manufactured by Tosoh Corporation Column: TSK-GelSuper HM-MX1
Column temperature: 40 ° C
Developing solvent: THF (tetrahydrofuran)
Flow rate: 0.6 mL / min
<Glass transition temperature (Tg)>
DSC apparatus Measuring instrument: “DSC6200” manufactured by Seiko Instruments Inc. Temperature condition: −30 ° C. to 100 ° C. (temperature increase rate: 8 ° C./min)
<Average particle size>
Laser diffraction / scattering type particle size distribution analyzer Measuring instrument: “LA-920” manufactured by Horiba, Ltd.

Example 1
With respect to 182 parts by mass of ethyl acetate, polyester-modified acrylic polyol resin [manufactured by Asia Ltd., trade name “NX-62-1”, Mw = 38,000, Tg = 47 ° C., hydroxyl value 19.0 mgKOH / g, Solid content concentration 54.9% by mass] 182 parts by mass (solid content 100 parts by mass), curing agent [manufactured by Asia Industry Co., Ltd., trade name “# 8000”, modified cyanurate of aliphatic diisocyanate, solid content concentration 48. 1% by mass. NCO content 10.1% by mass] 27.3 parts by mass (solid content 13.1 parts by mass), and rutile-type titanium oxide dispersion [manufactured by CI Chemical Co., Ltd., trade name “RTTDNB15WT% -E38”, average particle size 38 nm, solid content concentration of 15 mass%] 9.1 mass parts (solid content of 1.4 mass parts) was added to prepare a coating agent having a solid content concentration of about 29 mass%.
Next, white vinyl chloride resin adhesive sheet [manufactured by Lintec Corporation, trade name “Fuji Paint FP (M) 5011”, substrate film thickness 50 μm, adhesive layer: 30 μm thick acrylic, release sheet The coating agent is applied to the surface of [Appendix] so as to be 5 g / m ² after drying, and is heated at 70 ° C. for 1 minute to form a crosslinked acrylic urethane-based coating layer, An adhesive sheet for marking was prepared.
The performance evaluation results of this marking pressure-sensitive adhesive sheet are shown in Table 1.

Examples 2 to 5 and Comparative Example 1
Each marking pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the amount of the titanium oxide dispersion was changed as shown in Table 1.
The performance evaluation results of each marking pressure-sensitive adhesive sheet are shown in Table 1.
Reference example 1
Table 1 shows the performance evaluation results of the white vinyl chloride resin pressure-sensitive adhesive sheet (described above) without the coating layer.

As can be seen from Table 1, the marking pressure-sensitive adhesive sheets (Examples 1 to 5) of the present invention all pass the weather resistance, and Examples 2 and 3 are particularly excellent in the weather resistance. In Example 4, the gloss residual ratio was slightly low due to the titanium oxide choking, and in Example 5, one titanium oxide layer was formed due to the titanium oxide choking, and interference fringes were generated.
On the other hand, the comparative example 1 which does not use a rutile type titanium oxide particle has bad weather resistance.
Furthermore, the pressure-sensitive adhesive sheets for marking of Examples 1 to 5 are all good in stretching crack resistance, chemical scratch resistance, and chemical immersion resistance.

  The pressure-sensitive adhesive sheet for marking according to the present invention is particularly excellent in weather resistance, has chemical scratch resistance, chemical immersion resistance, crack resistance during stretching, and desired glossiness, and is suitably used, for example, for automobiles. .

Claims (6)

  While having a pressure-sensitive adhesive layer on one surface of the base film, (A) a polyester-modified acrylic polyol resin having a weight average molecular weight of 15,000 to 80,000, and (B) a polyisocyanate compound on the other surface A crosslinked acrylic urethane coating layer formed by using a coating agent containing 1 to 15 parts by mass of (C) rutile-type titanium oxide particles with respect to 100 parts by mass of the solid content of the component (A). A marking pressure-sensitive adhesive sheet comprising:   The pressure-sensitive adhesive sheet for marking according to claim 1, wherein the polyester-modified acrylic polyol resin as the component (A) has a glass transition temperature of 42 to 60 ° C.   (C) The pressure-sensitive adhesive sheet for marking according to claim 1 or 2, wherein the rutile-type titanium oxide particles have an average particle size of 10 to 100 nm.   (B) component polyisocyanate compound is aliphatic, cycloaliphatic, aromatic and araliphatic isocyanate, and adduct-modified, burette-modified, isocyanurate-modified, uretonimine-modified, uretdione-modified, The pressure-sensitive adhesive sheet for marking according to any one of claims 1 to 3, which is at least one selected from a modified carbodiimide and an elastically modified polyisocyanate.   The pressure-sensitive adhesive sheet for marking according to any one of claims 1 to 4, wherein the molar ratio [NCO] / [OH] of the isocyanate group of component (B) to the hydroxyl group of component (A) is 0.5 to 1.5. .   The pressure-sensitive adhesive sheet for marking according to any one of claims 1 to 5, wherein the crosslinked acrylic urethane-based coating layer has a thickness of 1 to 8 µm.