JP2002069398A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet of a low environmental loading type having excellent adhesiveness of a colored resin layer to a substrate layer with time, excellent application to a three-dimensional curved surface and handling workability due to flexibility and shape followingness, being readily dumped by a simple incinerator after use. SOLUTION: This adhesive sheet is obtained by laminating a colored resin layer 1, a polyolefin-based resin substrate layer 2 and an adhesive layer 3 in this order. The polyolefin-based resin substrate layer 2 comprises at least two layers of a skin layer 21 adjacent to the colored resin layer 1 and a supporting layer 22 adjacent to the adhesive layer. The adhesive layer 3 is stuck with a releasing agent layer 4, if required. The adhesive sheet is composed of four layers as a whole (five layers if the polyolefin-based resin substrate layer 2 composed of two layers is considered). The skin layer is made of a polyolefin- based resin having >=15% surface oxygen atom weight measured by an X-ray photoelectron spectrophotometer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet suitably used as an outdoor or indoor advertising sticker, a display sticker, a decorative sticker, or the like.
The pressure-sensitive adhesive sheet of the present invention also includes a pressure-sensitive adhesive film, and the pressure-sensitive adhesive sheet used for the above-mentioned applications is generally often referred to as a marking film.

[0002]

2. Description of the Related Art Such a marking film is generally made of a soft vinyl chloride-based resin film as a base layer, and the base layer is kneaded with a pigment according to the purpose or purpose, and then colored, printed or painted. After applying, a suitable pressure-sensitive adhesive (pressure-sensitive adhesive) is applied to one side of the base material layer according to the application and purpose, to form a pressure-sensitive adhesive layer. It is composed of laminated release material layers such as release paper and release film for the purpose of protection.When used, this release material layer is peeled off and the exposed pressure-sensitive adhesive layer is attached to a predetermined location on the adherend. Used with.

[0003] This marking film is often used outdoors, for example, for signs, billboards, shutters,
Advertising stickers used for shop windows, etc .;
Widely used for outdoor applications such as decorative stripe stickers used for vehicles such as automobiles and motorcycles and ships such as motor boats; and display stickers used for traffic signs, road signs, and information boards. For this reason, the marking film is required to have excellent weather resistance, and also have appropriate flexibility and shape followability for attaching to a cubic curved surface.

On the other hand, a conventional marking film using a soft vinyl chloride resin film as a base layer generates hydrogen chloride gas and dioxin when it is incinerated and discarded. Further, there is a problem that the durability of the incineration equipment is reduced. Therefore, recently, there has been an increasing demand for a low environmental load type marking film which can be processed by a simple incineration facility, and various attempts have been made.

For example, Japanese Patent Application Laid-Open No. 8-157780 discloses that "a film made of a composition obtained by mixing titanium oxide or the like with a polyolefin resin is used as a base material layer, and an adhesive layer and a release material layer are formed on the base material layer. An adhesive sheet which is formed and is easy to dispose by incineration "is disclosed.

However, in the case of the marking film described in this publication, titanium oxide is blended in order to provide the polyolefin-based resin base material layer with concealing properties, so that the colored resin layer formed on the surface of the base material layer cannot be used. Titanium oxide develops a photocatalytic action due to the ultraviolet rays and heat of the transmitted sunlight, and the resin at the interface of the base material layer in contact with the colored resin layer deteriorates, and the colored resin layer peels off from the base material layer with time. There was a problem that sometimes.

In order to address the above problems, generally,
There is a method in which a primer layer (undercoat layer) having high adhesiveness is provided on both the colored resin layer and the base material layer on the surface of the base material layer. Therefore, there is a problem that the manufacturing operation becomes complicated and the cost becomes disadvantageous.
In addition, the polyolefin resin used for the base layer is not specified at all, and in the case of a marking film produced using a base layer made of a commercially available polyolefin resin, a soft polyvinyl chloride resin is used as the base layer. Compared with the marking film, the flexibility and shape followability were inferior, so that the tertiary curved surface workability and handling workability were insufficient and could not be used for actual use.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the conventional pressure-sensitive adhesive sheet, it is an object of the present invention to improve the adhesion of the colored resin layer to the base material layer over time, and to improve the flexibility and shape following. An object of the present invention is to provide a low environmental load type pressure-sensitive adhesive sheet that is excellent in workability and handling workability on a cubic curved surface due to the property, and that can be easily disposed of by a simple incineration facility after use.

[0009]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 is an adhesive sheet comprising a colored resin layer, a polyolefin resin base material layer and an adhesive layer laminated in this order. The polyolefin-based resin base material layer includes at least two layers having a skin layer adjacent to the colored resin layer and a support layer adjacent to the pressure-sensitive adhesive layer, and the skin layer is measured by an X-ray photoelectron spectrometer. Provided is a pressure-sensitive adhesive sheet formed from a polyolefin resin having a surface oxygen atom weight of 15% by weight or more.

Further, the invention according to claim 2 is characterized in that the polyolefin resin of the support layer is a soft polypropylene resin 20 to
90% by weight and other polyolefin resin 80-1
The soft polypropylene resin has a weight-average molecular weight in the range of 80,000 to 500,000 and a resin elution amount of 0 ° C. or less by a cross fractionation method of 30 to 50%.
The pressure-sensitive adhesive sheet according to claim 1, wherein the amount of the resin eluted at 70% by weight, more than 0 ° C. and 70 ° C. or less is 5 to 30% by weight, and the amount of the resin eluted at a temperature exceeding 70 ° C. is 20 to 60% by weight. Further, in the invention according to claim 3, the colored resin layer has a pigment of 5 to 200 parts by weight based on 100 parts by weight of at least one kind of a crosslinked acrylic resin, polyester resin, and fluorine resin. The pressure-sensitive adhesive sheet according to claim 1, which is formed from the contained colored resin composition. Hereinafter, the present invention will be described in more detail.

FIG. 1 is a sectional view showing an embodiment of the pressure-sensitive adhesive sheet of the present invention. As shown in FIG. 1, the colored resin layer 1,
The polyolefin-based resin base material layer 2 and the pressure-sensitive adhesive layer 3 are laminated in this order, and the polyolefin-based resin base material layer 2 further includes:
It comprises at least two layers having a skin layer 21 adjacent to the colored resin layer 1 and a support layer 22 adjacent to the pressure-sensitive adhesive layer. A release material layer 4 is adhered to the pressure-sensitive adhesive layer 3 as necessary, and a total of four layers ( Considering that the polyolefin-based resin base material layer 2 is composed of two layers, it has a configuration of five layers).

[Colored resin layer] The resin used for the colored resin layer is not particularly limited, but, for example, a synthetic resin substantially containing no chlorine atom is preferably used. , Polyester resin, fluorine resin, urethane resin, polyacetal resin, polyamide resin, polyolefin resin, vinyl acetate resin, styrene resin, epoxy resin, ethylene-vinyl acetate copolymer (EVA), ethylene -Vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, styrene-
Conjugated diene copolymers and the like can be mentioned. In particular, an acrylic resin, a polyester resin, a fluorine resin, or the like is preferably used because of its excellent weather resistance and transparency. These synthetic resins may be used alone or in combination of two or more.

In accordance with the required functions such as weather resistance and strength, various polyols, melamine, silanol, a hydroxyl group structure, an alicyclic epoxy compound, and glycidyl methacrylate may be arranged inside the main chain of these synthetic resins. A three-dimensional crosslinked structure may be formed by reacting isocyanate, melamine, silane or the like as a crosslinking component. Depending on the required quality, the main chain itself can be modified with an acid, modified with silicone, modified with fluorinated, or blended with vinylidene fluoride or the like to impart adhesiveness or weather resistance. For example, as the fluorine-based resin, a fluoroethylene-based, vinylidene fluoride-based, fluoroethylene vinyl ether-based or fluororesin-grafted product, or an alkyl fluoride-grafted product on an acrylic main chain can be used.

Materials used as the crosslinking agent include isocyanates, melamines, and methylols.
In order to prevent the occurrence of yellowing due to light, it is preferable to select and use, for example, an aliphatic isocyanate that does not contain an aromatic ring. These crosslinking agents may be used alone or in combination of two or more. Usually, a cross-linking component and, if necessary, a curing accelerating catalyst are blended in the resin solution, and the resin solution is used in a pot life in which the liquid does not cure, and after curing, a cross-linked colored resin layer is formed.

The colored resin layer is made of, for example, a colored resin composition in which a coloring agent such as a pigment or a dye is blended. The pigment is not particularly limited. Pigments are used.

The colorant is not particularly limited, but may be, for example, titanium oxide, carbon black,
Red petals, cyanine blue, cyanine green, quinacridone red, polyazo yellow, diketopyrrolopyrrole, and the like are preferably used. These colorants may be used alone or in combination of two or more, in order to enable color development of a desired hue or color pattern,
It is preferable to select and use a colorant having excellent weather resistance, and it is preferable to select and use a colorant that does not contain a chlorine atom that is a source of harmful gas in the molecule.

In the pressure-sensitive adhesive sheet of the present invention, the colored resin layer has a pigment content of 5 to 200 parts by weight based on 100 parts by weight of at least one kind of synthetic resin of a crosslinked acrylic resin, polyester resin and fluorine resin. Is preferably formed from a colored resin composition containing When the amount of the pigment is less than 5 parts by weight, a desired hue or color pattern cannot be obtained. When the amount is more than 200 parts by weight, the viscosity of the colored resin composition becomes too high, so that coating or printing becomes difficult, and the obtained colored resin layer The appearance deteriorates. In addition, since the raw material unit price is generally high, the cost becomes uneconomical. Further, by using the above resin as the synthetic resin, the obtained colored resin layer has excellent weather resistance and transparency.

The above colored resin composition is preferably used in the form of a so-called paint or printing ink, but is not limited to these. The form of the colored resin composition is not particularly limited, and a solvent-type colored resin composition, an emulsion-type colored resin composition, a hot-melt-type colored resin composition, a film-shaped colored resin composition, for example, light Any form such as a monomer-type or oligomer-type colored resin composition capable of bulk polymerization such as photopolymerization by irradiation may be used.

The colored resin composition may be a one-part type, a two-part or more multi-part type, a cross-linked type, or a non-cross-linked type. It may be present, but in order to impart better weather resistance and durability to the obtained colored resin layer, a crosslinked type is preferable.

The above-mentioned colored resin composition may further contain an inorganic or organic filler, a softener, a plasticizer, a surfactant, a coupling agent, a leveling agent, if necessary, as long as the object of the present invention is not hindered. UV absorbers such as benzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, etc., light stabilizers such as hindered amine compounds, heat stabilizers, antioxidants (antiaging agents), antistatic agents One or more of various additives such as a flame retardant and an antifoaming agent may be contained, but it is preferable to select and use an additive substantially containing no chlorine atom.

The method for forming the colored resin layer on the skin layer of the polyolefin-based resin base material layer described below is not particularly limited. For example, depending on the form of the colored resin composition, for example,
Gravure coater, comma coater, knife coater,
Using a flow coater, a hot melt coater, a spray coating machine, a screen printing machine, a gravure printing machine, or the like, after coating or printing the colored resin composition on the outer layer of the base material layer, if necessary, drying, By performing crosslinking, cooling, light irradiation, or the like, a desired colored resin layer can be formed. The thickness of the colored resin layer thus formed is not particularly limited, but is preferably 5 to 40 μm.

[Polyolefin Resin Substrate Layer] The polyolefin resin substrate layer (hereinafter sometimes abbreviated as “substrate layer” as appropriate) includes a skin layer adjacent to the colored resin layer and an adhesive layer described below. And a support layer adjacent to the agent layer. The skin layer has a surface oxygen atom weight of 15% by weight measured by an X-ray photoelectron spectrometer.
It is necessary to be above.

The polyolefin resin constituting the base material layer is not particularly limited as long as it is a polyolefin resin containing substantially no chlorine atom. Among them, ethylene or propylene is a main constituent unit. Polymers are preferred. Specifically, low-density polyethylene resin (LD
PE), linear low density polyethylene resin (LLDP)
E), polyethylene resin such as high-density polyethylene resin (HDPE), polypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, ethylene-vinyl acetate copolymer (EV
A) and a hydroxyl group-containing polyolefin-based resin in which a hydroxyl group is introduced into these, are preferred examples. These polyolefin resins may be used alone or in combination of two or more.

If the surface oxygen atom weight of the skin layer is less than 15% by weight, the adhesion of the colored resin layer to the substrate layer becomes insufficient, and the colored resin layer peels off from the substrate layer with time. Sometimes. In order to make the surface oxygen atom weight in the skin layer 15% by weight or more, a so-called adhesive polyolefin resin such as an ethylene-vinyl acetate copolymer having an oxygen atom or a hydroxyl group-containing polyolefin resin is used alone or It is preferable to use them in combination.

By using a polyolefin resin having a surface oxygen atom weight of 15% by weight or more as the resin forming the skin layer, the adhesion of the colored resin layer to the obtained base material layer becomes excellent, Thereby, the colored resin layer hardly peels off from the base material layer.

The resin forming the skin layer contains an ultraviolet absorber and a hindered amine compound in order to prevent light deterioration.
It may be blended within a range that does not inhibit the achievement of the object of the present invention. As the ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, or an eztel salicylate-based ultraviolet absorber as conventionally used can be used. These may be used alone or in combination of several types. As the hindered amine-based compound, a substance which has been conventionally compounded in a polyolefin-based resin may be used, and one kind or a combination of several kinds may be used.

In the present invention, it is preferable to mix titanium oxide in the support layer of the base material layer in order to impart concealing properties to the polyolefin base material layer itself. Examples of the titanium oxide include rutile-type titanium oxide and anatase-type titanium oxide. Among them, rutile-type titanium oxide is preferably used because of excellent concealing property and weather resistance. The particle size of the titanium oxide is not particularly limited, but preferably has an average particle size of 0.01 to 1 μm because of excellent dispersibility in the polyolefin resin.

These titanium oxides may be used alone or in combination of two or more. The compounding amount is
With respect to 100 parts by weight of the polyolefin resin of the support layer,
Generally, it is 40 to 100 parts by weight. If the compounding amount is less than 40 parts by weight, the concealing properties of the obtained base material layer and the entire pressure-sensitive adhesive sheet become insufficient, and if it exceeds 100 parts by weight, the polyolefin is not improved anymore. The dispersibility of titanium oxide in the system resin becomes poor, and the moldability of the support layer becomes insufficient, making it difficult to obtain a good base layer having a two-layer structure.

The method for incorporating titanium oxide into the polyolefin resin is not particularly limited. For example, a predetermined amount of titanium oxide is directly added to the polyolefin resin, and the mixture is stirred, mixed and dispersed. Preparation method and a titanium oxide masterbatch prepared by uniformly dispersing titanium oxide in a high concentration in a polyolefin resin in advance, and adding this masterbatch to the polyolefin resin so that the titanium oxide becomes a predetermined amount. Then, a method of stirring and mixing and dispersing, etc. may be mentioned, but the latter method is preferable because more uniform dispersibility can be obtained.

The polyolefin resin constituting the support layer in the base layer is preferably a soft polypropylene resin or a blend of a soft polypropylene resin and another polyolefin resin. More preferred polyolefin resin is soft polypropylene resin 20.
~ 90% by weight and other polyolefin resin 80 ~
The soft polypropylene resin has a weight average molecular weight in the range of 80,000 to 500,000, and has a resin elution amount of 0 ° C or less by the cross fractionation method of 30% or less.
The resin elution amount is from 5 to 30% by weight at a temperature exceeding 70 ° C and 0 ° C to 70 ° C, and the resin elution amount at a temperature exceeding 70 ° C is 20 to 60% by weight. When such a pressure-sensitive adhesive sheet of the present invention is used as a marking film, an appropriate tertiary curved surface workability can be exhibited while maintaining appropriate film strength and waist strength in the base material layer and the entire marking film.

A preferred embodiment of the soft polypropylene resin is a propylene-ethylene copolymer or a propylene-α-olefin copolymer. In order to obtain such a soft polypropylene-based resin, for example, as a first step, polymerization is carried out using a propylene monomer and, if necessary, an α-olefin monomer other than propylene in the presence of a titanium compound catalyst and an aluminum compound catalyst. To obtain a first polypropylene-based polyolefin. In the second step, the titanium-containing polypropylene-based polyolefin produced in the first step is copolymerized with propylene, ethylene, or α-olefin in the presence of the titanium compound catalyst to obtain a second polypropylene-based polyolefin. Hereinafter, it can be obtained by performing a multi-stage copolymerization reaction according to the purpose in the same manner.

More preferred soft polypropylene-based resin is that the polypropylene-based polyolefin produced in the first step is a propylene homopolymer, a propylene-ethylene copolymer, or a propylene-α-olefin copolymer.

The weight average molecular weight of the soft polypropylene resin is, for example, a high temperature GPC (150
CV). The weight average molecular weight of the soft polypropylene resin used in the present invention according to claim 2 is 8
000-500,000, preferably 20
It is between 0.00000 and 400,000. If the weight average molecular weight is less than 80,000, the film strength is insufficient, and
If it exceeds 0.000, sufficient flexibility cannot be obtained.

The measurement of the amount of resin eluted by the cross fractionation method used in the present invention is performed as follows. First, the polypropylene resin is dissolved in O-dichlorobenzene at 140 ° C. or at a temperature at which the polypropylene resin is completely dissolved,
After cooling at a constant rate, a thin polymer layer is formed on the surface of a previously prepared inert carrier in the order of crystallinity and molecular weight.

Next, the temperature of the formed polymer layer is raised continuously or stepwise, the concentration of the components eluted sequentially is detected, and the composition distribution (crystallinity distribution) is measured (temperature-elution elution fractionation). At the same time, the molecular weight and molecular weight distribution of the component are measured by high-temperature GPC. For example, the temperature rise elution fraction (TREF = Temperature Rising Elution Fracti
onation) part and high temperature GPC (GelPermeation Chrom)
A cross-separation chromatograph (CFC-T150A: manufactured by Mitsubishi Yuka Co., Ltd.) having a system (atography) as a system is used.

The preferred soft polypropylene resin has a resin elution amount of 0 ° C. or less by the above-mentioned cross fractionation method of 30 to 70% by weight of the total amount of the polypropylene resin. If it is less than 30% by weight, the film lacks flexibility, and if it exceeds 70% by weight, sufficient strength as a film cannot be obtained. The resin elution amount at more than 0 ° C. and 70 ° C. or less is 5 to 30% by weight based on the total amount of the polypropylene resin. If it is less than 5% by weight, the film lacks flexibility, and if it exceeds 30% by weight, the film has poor deformation recovery properties. The resin elution amount at a temperature exceeding 70 ° C. is 20 to 60% by weight based on the total amount of the polypropylene resin. If it is less than 20% by weight, the film has poor deformation recovery properties,
If it exceeds 60% by weight, the strength as a film cannot be obtained. If the amount of the soft polypropylene resin is less than 20% by weight, the film cannot have an appropriate stress relaxation property and the tertiary curved surface workability deteriorates. On the other hand, if the content exceeds 90% by weight, the film is very soft, and the film handling becomes very poor.

Commercially available flexible soft polypropylene resins described above include "PER" manufactured by Tokuyama and Montel S.
DK Sunrise's “Cataroy” and the like can be used, and any of these can be used as the raw material resin for the pressure-sensitive adhesive sheet of the present invention. There is no problem even if another layer is laminated between the skin layer and the support layer as long as it does not hinder the present invention.

The above-mentioned polyolefin resin composition forming the base layer may contain, if necessary, an antistatic agent, an antiblocking agent, an antioxidant (antioxidant), as long as the object of the present invention is not hindered. Inorganic or organic fillers, softeners, plasticizers, surfactants, coupling agents, heat stabilizers,
One or more of various additives such as a light stabilizer, an ultraviolet absorber, a lubricant, and a flame retardant may be contained, but it is possible to select and use an additive substantially containing no chlorine atom. preferable.

The total thickness of the base material layer is usually 20 to 1
It is 50 μm, and preferably 40-60 μm.
If it is less than 20 μm, the obtained marking film itself will be too soft, so that it will be difficult to apply or insufficient strength.If it exceeds 150 μm, it will be harder, and it will be inferior to adherends such as cubic curved surfaces. Tearability is also an issue.

The ratio of the base material layer is preferably (skin layer / support layer) = (1/50) to (1/1). Considering the extruding function at the film formation stage and the cost estimation by blending the weathering agent, it is preferable. , (Skin layer / support layer) = (1/10)-(1 /
5) is more preferable.

The method of forming the base material layer is not particularly limited. For example, after blending the above-mentioned additives with a polyolefin resin, a T-die method, an inflation method or the like which has been conventionally used. It is preferable to extrude the skin layer and the support layer in two layers with a T-die from the viewpoint of excellent film formation and excellent productivity. Since the formed substrate layer generally has a low surface tension, it is desirable to improve the adhesion to the colored resin layer and the pressure-sensitive adhesive layer by a surface modification treatment such as a corona discharge treatment.

[Pressure-sensitive adhesive layer] The pressure-sensitive adhesive used as the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and examples thereof include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a polyvinyl ether-based pressure-sensitive adhesive, and a silicone. Although there are many types of adhesives, considering that they are often used outdoors,
An acrylic pressure-sensitive adhesive excellent in weather resistance and transparency is preferable.

The acrylic pressure-sensitive adhesive is not particularly limited, but, for example, an alkyl group having 1 to 1 carbon atoms.
(Meth) acrylic acid ester monomers of alcohols having 2 alkyls, preferably alkyl groups having 4 carbon atoms
A homopolymer of a (meth) acrylate monomer having an alkyl of from 12 to 12 or a copolymer of (meth) acrylate monomers, or the above (meth) acrylate monomer and the (meth) acrylate monomer Those containing a copolymer with a polymerizable monomer capable of being copolymerized as a main component are exemplified. In addition, (meth) acrylate referred to in the present invention means acrylate or methacrylate.

The (meth) acrylate monomer having alkyl having 4 to 12 carbon atoms in the alkyl group is not particularly limited. For example, (meth) acrylic acid n
-Butyl, 2-ethylhexyl (meth) acrylate,
Examples thereof include isooctyl (meth) acrylate, n-octyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate. These can be used alone or in combination. However, in order to obtain a good balance between the adhesiveness of the resulting pressure-sensitive adhesive and the adhesive strength and cohesiveness, the glass transition temperature of the homopolymer is usually used. (Tg) whose main component is an alkyl (meth) acrylate having a temperature of -50 ° C or lower, and further used together with a (meth) acrylate of a lower alcohol such as methyl (meth) acrylate and ethyl (meth) acrylate. Is preferred.

The monomers copolymerizable with these other than the vinyl monomers include carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid, anhydrides thereof, and 2-hydroxyethyl. (Meth) acrylate, 4-hydroxybutyl acrylate, polyoxyethylene (meth) acrylate,
Examples include hydroxyl group-containing monomers such as polyoxypropylene (meth) acrylate and modified caprolactone (meth) acrylate. These polymerizable monomers may be used alone or in combination of two or more.

The form of the pressure-sensitive adhesive used in the present invention including the above-mentioned acrylic pressure-sensitive adhesive is not particularly limited.
For example, it may be in any form of a solvent-type adhesive, an emulsion-type adhesive, a hot-melt-type adhesive, a monomer-type or oligomer-type adhesive capable of bulk polymerization such as photopolymerization by light irradiation. In addition, the pressure-sensitive adhesive,
It may be a crosslinked type or a non-crosslinked type.
It may be a liquid type or a multi-liquid type of two or more liquids.

In the above-mentioned pressure-sensitive adhesive, a tackifier, a coupling agent, an inorganic or organic filler, a softener, a plasticizer, a surface active agent may be used, if necessary, as long as the achievement of the object of the present invention is not hindered. Addition of one or more of various additives such as chemicals, antioxidants (antiaging agents), heat stabilizers, light stabilizers, ultraviolet absorbers, colorants, defoamers, antistatic agents, flame retardants, etc. However, it is preferable to select and use an additive that does not substantially contain a chlorine atom.

The thickness of the pressure-sensitive adhesive layer formed by using the above-mentioned pressure-sensitive adhesive after drying is not particularly limited.
It is preferably from 50 μm to 50 μm. When the thickness of the pressure-sensitive adhesive layer after drying is less than 20 μm, the resulting marking film may have insufficient tackiness or tackiness, and conversely, the dried pressure-sensitive adhesive layer may have a thickness of 50 μm. If it exceeds, the pressure-sensitive adhesive layer (glue) tends to seep out from the end of the obtained marking film, and dust adheres to it, or the pressure-sensitive adhesive layer causes cohesive failure when the marking film is peeled off after use, Adhesive residue may occur on the surface of the adherend.

The release material generally adhered to the pressure-sensitive adhesive layer is not particularly limited. For example, a silicone resin-based release agent or a long-chain alkyl group pendant-type graft polymer-based release agent may be used to remove paper or paper. A release paper or a release film obtained by subjecting at least one surface of a plastic film or the like to a release treatment is exemplified.

The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited. For example, the pressure-sensitive adhesive is coated on the release-treated surface of the release material by a reverse coating method, a hot melt coating method, or the like so as to have a predetermined coating thickness. Coated, dried, if necessary
After forming a pressure-sensitive adhesive layer having a predetermined thickness after drying through steps such as crosslinking, cooling, and light irradiation, a skin layer of the pressure-sensitive adhesive layer and a skin layer of a base material layer prepared in advance by, for example, a two-layer coextrusion method. A desired marking film can be obtained by laminating the surface of the support layer of the base material layer on which the colored resin layer is pre-laminated by the above-described forming method and transferring the pressure-sensitive adhesive layer to the base material layer side. . The method for producing the pressure-sensitive adhesive sheet of the present invention is not limited to the above method. First, the pressure-sensitive adhesive layer and the release material layer are laminated on the surface of the support layer of the base material layer prepared in advance, and then the base material is laminated. The method of laminating the colored resin layer on the surface of the skin layer of the layer may be adopted, and the laminating of the colored resin layer on the surface of the skin layer of the substrate layer and the pressure-sensitive adhesive layer on the surface of the support layer of the substrate layer Alternatively, a method of simultaneously performing lamination of the release material layer may be adopted.

(Function) In the pressure-sensitive adhesive sheet of the present invention, the skin layer adjacent to the colored resin layer of the base material layer is formed of a polyolefin resin having a specific surface oxygen atom concentration. The adhesiveness with the layer is excellent, and the colored resin layer hardly peels off from the base layer over time.

Further, in the pressure-sensitive adhesive sheet according to the present invention, the polyolefin resin of the support layer of the base layer comprises a specific amount of a soft polypropylene resin and a specific amount of other polyolefin resins, The soft polypropylene resin has a weight-average molecular weight in a specific range, and the amount of elution in each temperature range determined by the cross separation method is specified, so that the soft polypropylene resin has appropriate flexibility, shape conformability, and film strength. Excellent in tertiary curved surface workability and handling workability.

Further, since the pressure-sensitive adhesive sheet of the present invention does not substantially contain chlorine atoms, it is a low environmental load type which can be easily disposed of by incineration after use.

[0054]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples, “parts” means “parts by weight”.

In this example, the following raw materials were used. 1. Polyolefin resin for base material layer (1) EVA (manufactured by Tosoh Corporation, trade name "750", vinyl acetate content 32% by weight) (2) EVA (manufactured by DuPont Mitsui Polychemicals, trade name "P1207", acetic acid (3%) Polypropylene adhesive resin (trade name "P513V", manufactured by Mitsubishi Chemical Corporation) (4) Polyethylene adhesive resin (trade name "AT1243", manufactured by Mitsui Chemicals, Inc.) (5) Soft polypropylene-based resin (Montel SDK SDK Sunrise resin): weight-average molecular weight 313,000, resin elution at 0 ° C. or less by cross fractionation 47% by weight,
A resin having a resin elution amount of 20% by weight at a temperature higher than 0 ° C and 70 ° C or lower and a resin elution amount of 33% by weight at a temperature higher than 70 ° C was used. (6) PP (manufactured by Nippon Polychem, trade name "F327",
(MFR 7.0 g / 10 min) (7) LLDPE (trade name “FR152” manufactured by Tosoh Corporation)
C ", MFR 0.80 / 10 minutes)

2. Titanium oxide Rutile type titanium oxide (trade name "CR-60", manufactured by Ishihara Sangyo Co., Ltd.)

3. Colored resin composition for colored resin layer (1) Polyester resin paint (trade name "Planit U"
# 500 ", manufactured by Dai Nippon Paint Co., Ltd. (2) Fluorine-based resin paint (trade name" Duflon Pure Clear ", manufactured by Nippon Paint Co., Ltd.) (3) Acrylic resin paint (trade name" Leatheric T "
C ", Fujikura Kasei Co., Ltd.)

In each of the above paints, the clear resin content 1
A mixture of 40 parts of a composite pigment (manufactured by Dainichi Seika Kogyo Co., Ltd.) composed of cyanine blue, quinacridone red, polyazo yellow, and cyanine green as a colorant was used as a coloring agent. A colored resin composition obtained by blending 6.5 parts of trade name "Coronate 2094", manufactured by Nippon Polyurethane Industry Co., Ltd.) was used. However, in Comparative Example 5, 250 parts of the above-mentioned composite pigment as a coloring agent and the above-mentioned isocyanate-based compound as a cross-linking agent were used as the coloring resin composition for 100 parts of the clear resin component of the polyester resin coating “Planit U # 500”. What mixed 6.5 parts was used.

4. 4. Pressure-sensitive adhesive for pressure-sensitive adhesive layer Two-component crosslinkable acrylic solvent-type pressure-sensitive adhesive (trade name "BPS5520", manufactured by Tokyo Ink Co., Ltd.) Release material Release paper that has been release treated with a silicone resin-based release agent

(Example 1) E for a skin layer of a substrate layer
A polyolefin resin comprising 70 parts of VA "750" and 30 parts of a soft PP resin was prepared. Further, 50 parts of a soft PP resin and LLDPE “FR15”
50 parts of "2C" were prepared.

An X-ray photoelectron spectrometer (KRATO)
The surface oxygen atom concentration of the polyolefin resin for a skin layer measured under the following measurement conditions using a model “AXIS-165 type” manufactured by S Company) was 25.2% by weight. [Method of measuring surface oxygen atom concentration] X-ray source: monochromatic Al-Kα Analysis diameter: 300 × 700 μm Voltage: 15 kV Current: 5 mA Pass energy: 40 eV

Using a T-die, two layers of the above-mentioned polyolefin resin for the skin layer and the polyolefin resin for the support layer were co-extruded so that the thickness of the skin layer became 10 μm and the thickness of the support layer became 40 μm. After forming a film with a thickness of 50 μm, corona discharge treatment (24 × 1
0 ^-5 N / cm) to produce a substrate layer in which a corona discharge treatment was applied to the skin layer surface and the support layer surface.

Next, a spray gun coater (coating machine)
The polyester resin-based paint ("Planit U # 500") was spray-coated on the skin layer surface of the base material layer so that the thickness after drying was 20 μm, dried, and a colored resin layer was laminated. . Next, using a comma coater, a two-part crosslinkable acrylic solvent-based pressure-sensitive adhesive “BPS” was applied to the release-treated surface of release paper that had been release-treated with a silicone resin-based release agent.
5520 "was applied so that the thickness after drying was 40 μm, and dried to form an adhesive layer. Thereafter, this pressure-sensitive adhesive layer was laminated on the support layer surface of the base material layer to obtain a target marking film.

(Examples 2 to 5) and (Comparative Examples 1 to 4) Colored resins were used as shown in Table 1 as the polyolefin resin for the skin layer and the polyolefin resin for the support layer of the base material layer. A marking film was obtained in the same manner as in Example 1 except that the colored resin composition shown in Table 1 was used for the layer. However, in Comparative Example 3, when the surface oxygen atom concentration of the base material layer composed of only the support layer without forming the skin layer was measured, it was 14.5% by weight. In Comparative Example 4, a colored resin composition was prepared in which the resins of the skin layer and the support layer were as shown in Table 1 and the ratio of the composite pigment was 250 parts with respect to 100 parts of the resin. Except for the above, it was attempted to obtain a marking film in the same manner as in Example 1, but the viscosity of the colored resin composition was too high to apply to the base material layer. Could not be provided. Therefore, various evaluations were impossible.

The surface oxygen atom concentration of the skin layer of the substrate layer was measured in the same manner as in Example 1. The results were as shown in Table 1.

Example 6 A marking film was obtained in the same manner as in Example 1 except that the colored resin layer was prepared using a fluorine-based paint ("Duflon Pour Clear"). (Example 7) A marking film was obtained in the same manner as in Example 1 except that the colored resin layer was prepared using an acrylic paint ("Leatheric TC").

[Evaluation of Marking Film] Examples 1 to
The moldability of the base layer prepared in Example 7 and Comparative Examples 1 to 4, the formability of the colored resin layer, the adhesion with time of the marking film, the handling workability, and the tertiary curved surface workability were evaluated by the following methods. did. The results were as shown in Table 2. However, in Comparative Example 4, the subsequent evaluation was not performed because the colored resin layer could not be formed.

Formability of base layer: The formability of the base layer by the two-layer coextrusion method was evaluated according to the following criteria. (Judgment Criteria) O The two-layered base material layer could be formed without any problem. X: Two-layer coextrusion could not be performed.

Formability of the colored resin layer: The coatability when the paint for the colored resin layer was spray-coated on the outer layer surface of the base material layer and the appearance of the formed colored resin layer were visually observed, and the following judgment was made. The formability of the colored resin layer was evaluated based on criteria. (Judgment Criteria) O: There was no problem in coatability, and the appearance of the formed colored resin layer was also good. C: The spray gun clogged during coating, and a good colored resin layer could not be formed.

Adhesion over time: Xenon weatherometer (black panel temperature: 63 ° C., water spray time: 12 minutes / 60 minutes) with the adhesive layer exposed by peeling off the release paper of the marking film and adhered to an aluminum plate. After 2,000 hours exposure, a cross-cut test was performed by a cross-cut method in accordance with JIS K-5400 "General Test Methods for Paints" to count the number of peeled colored resin layers. The temporal adhesion between the layer and the colored resin layer was evaluated. (Judgment criteria) ○ ‥‥ The number of peeled colored resin layers was 10 or less / 100. Δ ‥‥ The number of peeled colored resin layers was 11 to 30/100. × ‥‥ The number of peeled colored resin layers was 31 or more / 100.

Handling workability: The handling workability of the marking film after the release paper was peeled was evaluated according to the following criteria. (Judgment Criteria) ○ ‥‥ Since the marking film had moderate flexibility, the handling operation could be performed without any problem. Δ ‥‥ The handling operation was slightly difficult because the marking film was slightly too soft. × ‥‥ Since the marking film was extremely soft,
Handling work could not be performed.

Tertiary curved surface workability: 5 shown in FIG. 2 is a sectional view of a corrugated plate used for evaluation of the tertiary curved surface workability. After releasing the release paper of the marking film and bonding the exposed adhesive layer of the marking film to the peak of the corrugated plate 5 having the tertiary curved surface shown in FIG. 2, a special installation tool ( Using a special spatula), the pieces were pressed and bonded. The workability at this time was evaluated according to the following criteria. (Judgment criteria) ○ ‥‥ Since the marking film had moderate flexibility, it could be adhered to the corrugated plate without any problem. Δ ‥‥ Since the modulus of the marking film was somewhat unsuitable, it was somewhat difficult to apply the adhesive to the corrugated plate. × ‥‥ Since the modulus of the marking film was unsuitable, it was extremely difficult to apply it to the corrugated plate.

[0073]

[Table 1]

[0074]

[Table 2]

As is clear from Tables 1 and 2, all of the marking films of Examples 1 to 7 according to the present invention exhibited excellent performance for all evaluation items.

On the other hand, the marking film of Comparative Example 1 provided with a base layer comprising a skin layer having a surface oxygen atom concentration of less than 15% by weight and a support layer not using a soft polypropylene resin as a polyolefin resin. Was poor in aging adhesion and tertiary curved surface workability. Further, without a skin layer, the surface oxygen atom concentration is less than 15% by weight,
The marking film of Comparative Example 2 having the base layer composed of the support layer made of the soft polypropylene resin had poor adhesion with time and workability. In addition, the marking film of Comparative Example 3 including the base layer having the skin layer having the surface oxygen atom concentration of less than 15% by weight had poor adhesion with time.

[0077]

The pressure-sensitive adhesive sheet of the present invention has excellent adhesion between the colored resin layer and the substrate layer, so that the colored resin layer hardly peels off from the substrate layer over time, and has an appropriate flexibility. It is excellent in tertiary curved surface workability and handling workability because it has shape followability and strength, and it is a low environmental load type that can be easily disposed of by incineration after use, so it is a marking film for indoor use Naturally, for example, it is suitably used as a marking film for outdoor applications such as advertising stickers, decoration stickers, and display stickers.

[0078]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer configuration of a pressure-sensitive adhesive sheet of the present invention.

FIG. 2 is a cross-sectional view showing a corrugated plate used for evaluation of tertiary curved surface workability.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Colored resin layer 2 ... Base layer 21 ... Skin layer 22 ... Support layer 3 ... Adhesive layer

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) 4F100 AA21C AH02A AH03A AK01A AK03B AK03C AK04B AK06C AK07B AK07C AK17A AK24A AK24D AK41A AK52E AK68B AL05A AL05B AL05C BA04 BA05 BA07E10 JK17 JL10A JL11 JL11B JL11C JL13 JL13D JL14E YY00A YY00B YY00C 4J004 AB01 CA04 CC03 CD01

Claims (3)

[Claims] 1. A pressure-sensitive adhesive sheet in which a colored resin layer, a polyolefin-based resin base material layer and a pressure-sensitive adhesive layer are laminated in this order, wherein the polyolefin-based resin base material layer has a skin layer adjacent to the colored resin layer and The skin layer is formed of a polyolefin-based resin having a surface oxygen atom weight of 15% by weight or more as measured by an X-ray photoelectron spectrometer, comprising at least two layers having a support layer adjacent to the pressure-sensitive adhesive layer. An adhesive sheet characterized by the above-mentioned. 2. The polyolefin resin of the support layer comprises 20 to 90% by weight of a soft polypropylene resin and 80 to 10% by weight of another polyolefin resin. The soft polypropylene resin has a weight average molecular weight of 80,
The resin elution amount at 0 ° C or less by the cross fractionation method is 30 to 70% by weight, the resin elution amount at more than 0 ° C and 70 ° C or less by 5 to 30% by weight,
2. The pressure-sensitive adhesive sheet according to claim 1, wherein the resin elution amount at a temperature exceeding 70 [deg.] C. is 20 to 60% by weight. 3. A pigmented resin layer comprising at least one of a crosslinked acrylic resin, a polyester resin and a fluororesin, and 100 parts by weight of a synthetic resin.
The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet is formed from a colored resin composition containing parts by weight.