JP7023682B2 - Adhesive film, manufacturing method of adhesive film and manufacturing method of printed matter - Google Patents

Description

The present invention relates to an adhesive film , a method for producing an adhesive film, and a method for producing a printed matter .

The print label is configured, for example, by applying the desired printing to the surface of the adhesive film.
As a print label, a label having a printing portion formed on a plastic film by using an ultraviolet curable ink (UV ink) is known. By using UV ink, it is not necessary to use a volatile organic solvent, so that it is environmentally friendly, does not require a drying process, and can efficiently form a printed portion.

Then, as an adhesive film to which UV ink is applied, in order to improve the adhesion with UV ink, a layer made of a material containing a component having a reactive functional group is provided on the printing surface side. It is known (see, for example, Patent Document 1).

However, in the past, when printing with UV ink, the reactivity with UV ink was insufficient, and the adhesion of the printed portion was sometimes lowered. Such a problem occurred more prominently when stored for a long period of time.

Special Table 2000-513663 Gazette

An object of the present invention is to provide an adhesive film having excellent storage stability and excellent adhesion to an ultraviolet curable ink (printed matter by an ultraviolet curable ink) even when stored for a long period of time. It is an object of the present invention to provide a method for producing an adhesive film capable of producing the same, and to provide a method for producing a printed matter having excellent adhesion of an ultraviolet curable ink (printed matter by an ultraviolet curable ink) .

Such an object is achieved by the present invention described in the following (1) to ( 10 ).
(1) An adhesive film used for printing using ultraviolet curable ink.
With the base material
A printing coat layer provided on the first surface side, which is one surface of the base material, and made of a material containing a component having an ultraviolet polymerizable functional group.
An adhesive layer provided on the second surface side, which is a surface opposite to the first surface of the base material, and
A release liner that protects the adhesive layer is provided .
It is stored in a rolled state and is stored.
The ultraviolet polymerizable functional group reacts with the ultraviolet curable functional group of the ultraviolet curable ink by being irradiated with ultraviolet rays after the ultraviolet curable ink is applied.
An adhesive film characterized in that the transmittance of ultraviolet rays of the adhesive film is 40% or less.

(2) The adhesive film according to (1) above, wherein the laminated body portion of the adhesive film other than the printing coat layer contains an ultraviolet blocking agent.

(3) The pressure-sensitive adhesive film according to (2) above, which contains the ultraviolet blocking agent in the pressure-sensitive adhesive layer.

(4) The pressure-sensitive adhesive film according to any one of (1) to (3) above, wherein the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive.

(5) The pressure-sensitive adhesive film according to any one of (1) to (4) above, wherein the base material is made of a material containing at least one of polyolefin and polyester.
(6) A method for producing an adhesive film according to any one of (1) to (5) above.
A printing coat layer forming step of forming a printing coat layer on one surface of a base material using a coating liquid containing a material containing a component having an ultraviolet polymerizable functional group.
A method for producing a pressure-sensitive adhesive film, which comprises a pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer on the other surface of the base material.
(7) The method for producing an adhesive film according to (6) above, wherein the printing coat layer forming step is performed prior to the pressure-sensitive adhesive layer forming step.
(8) The method for producing an adhesive film according to (6) above, wherein the printing coat layer forming step is performed after the pressure-sensitive adhesive layer forming step.
(9) The method for producing an adhesive film according to any one of (6) to (8) above, wherein the coating liquid is not irradiated with ultraviolet rays after being applied.
(10) An ultraviolet curable ink applying step of applying an ultraviolet curable ink onto the printing coat layer of the adhesive film according to any one of (1) to (5) above.
By irradiating the ultraviolet curable ink applied on the printing coat layer with ultraviolet rays, the curing reaction of the ultraviolet curable ink is promoted, and the ultraviolet curable functional group of the ultraviolet curable ink and the printing are performed. A method for producing a printed matter, which comprises an ultraviolet irradiation step of advancing a reaction with an ultraviolet polymerizable functional group in a coating layer for printing.

According to the present invention, it is possible to provide an adhesive film having excellent adhesion to an ultraviolet curable ink (printed portion by an ultraviolet curable ink) even when stored for a long period of time, and to manufacture the adhesive film. It is possible to provide a method for producing an adhesive film and to provide a recorded material having excellent adhesion of an ultraviolet curable ink (printed portion by an ultraviolet curable ink) .

It is a schematic vertical sectional view which shows the preferable embodiment of the adhesive film of this invention. It is a schematic block diagram which shows an example of the structure of a printing machine (flexographic printing machine).

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Adhesive film]
First, the adhesive film of the present invention will be described.
FIG. 1 is a schematic vertical sectional view showing a preferred embodiment of the pressure-sensitive adhesive film of the present invention.

The pressure-sensitive adhesive film 10 includes a base material 11, a printing coat layer 12 provided on the first surface side, which is one side of the base material 11, and made of a material containing a component having an ultraviolet polymerizable functional group. A pressure-sensitive adhesive layer 13 provided on the second surface side opposite to the first surface of the base material 11 and a release liner 14 for protecting the pressure-sensitive adhesive layer 13 are provided. The adhesive film 10 is stored in a rolled state, and has an ultraviolet transmittance (wavelength region: average transmittance in a wavelength region of 300 nm or more and 380 nm or less) of 40% or less.

Such an adhesive film 10 is used as a print label by, for example, applying a desired print on the surface with an ultraviolet curable ink (UV ink).

The adhesive film 10 is generally traded in a rolled state and stored indoors such as a warehouse until use (printing).

Such an adhesive film 10 has excellent storage stability, and can maintain excellent adhesion to an ultraviolet curable ink (adhesion to a printed portion by an ultraviolet curable ink) even when stored for a long period of time. can.

In the present specification, the transmittance of ultraviolet rays of the adhesive film 10 is, as shown in FIG. 1, a normal line from the surface side where the adhesive film 10 is developed in a plane and the printing coat layer 12 is provided. It refers to the transmittance of ultraviolet rays when ultraviolet rays are applied along the direction. The same applies to the transmittance of ultraviolet rays for each portion constituting the adhesive film 10.

Conventionally, in an adhesive film provided with a layer (printing coat layer) made of a material having a reactive functional group (ultraviolet polymerizable functional group) for improving adhesion with UV ink. When printing with UV ink, the reactivity with UV ink is insufficient, and the adhesion of the printed portion may be deteriorated, resulting in impaired printability. Such a problem occurred more prominently when stored for a long period of time.

Therefore, the present inventor has conducted diligent research for the purpose of solving such a problem. As a result, it has been found that the above-mentioned problems are caused by the deterioration of the printing coat layer due to the reaction of the component having an ultraviolet polymerizable functional group with ultraviolet rays in sunlight or the like during storage. The present invention has been reached.

Specifically, as will be described later, when printing is performed on the adhesive film 10 with a printing machine (for example, a flexographic printing machine), usually, about three rounds of the outermost layer of the adhesive film 10 wound in a roll shape are formed. It is used for passing paper when setting it in a printing machine. This part is not printed and is usually discarded. Therefore, even if this portion (about 3 rounds of the outermost layer) deteriorates due to the reaction with ultraviolet rays and the printability is impaired, there is no effect.

In the present invention, it is sufficient if the influence of ultraviolet rays can be suppressed on the adhesive film 10 on the fourth and subsequent laps (inside the fourth lap) from the outside of the roll, which is actually used for printing.

When the transmittance of the ultraviolet rays of the adhesive film 10 satisfies the above conditions, for example, when the adhesive film 10 is stored indoors (for example, a place where sunlight is inserted but not exposed to direct sunlight) for a long period of time (for example,). Even after 2 years or more), sufficient quality (adhesion of the printed portion, printing characteristics, etc.) can be maintained.

As described above, the transmittance of the ultraviolet rays of the adhesive film 10 is 40% or less, preferably 35% or less, more preferably 30% or less, still more preferably 25% or less. ..
As a result, the above-mentioned effects are more prominently exhibited.

The means for setting the transmittance of the ultraviolet rays of the adhesive film 10 to a predetermined value or less is not particularly limited, but can be easily and surely realized by, for example, containing an ultraviolet ray blocking agent in the adhesive film 10.

The lower limit of the ultraviolet ray transmittance of the adhesive film 10 is not particularly limited, but if an attempt is made to lower the ultraviolet ray transmittance of the adhesive film 10 more than necessary, the degree of discoloration (coloring) of the adhesive film 10 by the ultraviolet blocking agent May become noticeable, or the characteristics of the portion containing the ultraviolet blocking agent (for example, the adhesive force in the pressure-sensitive adhesive layer 13, the peeling force in the release liner 14, etc.) may be unintentionally lowered. From such a viewpoint, the transmittance of ultraviolet rays of the adhesive film 10 is preferably 0.1% or more, more preferably 0.2% or more, and further preferably 0.3% or more. ..

When the pressure-sensitive adhesive film 10 contains an ultraviolet blocking agent, at least one of the laminated body portion (for example, the base material 11, the pressure-sensitive adhesive layer 13, and the release liner 14) of the portion other than the printing coat layer 12 of the pressure-sensitive adhesive film 10. ) Preferably contains a UV blocking agent

As a result, the transmittance of ultraviolet rays as a whole of the adhesive film 10 can be effectively reduced, and the unwilling reaction of the component having an ultraviolet polymerizable functional group contained in the printing coat layer 12 at the time of storage or the like. Can be suppressed more effectively.

Among the laminated parts other than the printing coat layer 12, the base material 11 and the printing coat layer 12 are formed by bleeding out the ultraviolet blocking agent by impregnating the portion other than the base material 11 with the ultraviolet blocking agent. It is possible to more effectively prevent the occurrence of problems such as deterioration of the adhesion of UV rays. Further, a commercially available film can be suitably applied to the base material 11, which is advantageous from the viewpoint of improving the productivity of the adhesive film 10 and reducing the manufacturing cost.

For this reason, it is particularly preferable that the ultraviolet blocking agent is contained in the pressure-sensitive adhesive layer 13. Since the pressure-sensitive adhesive layer 13 is not adjacent to the printing coat layer 12, even if the ultraviolet blocking agent contained in the pressure-sensitive adhesive layer 13 bleeds out, the influence on the printing coat layer 12 can be suppressed.

In the following description, among the laminates constituting the pressure-sensitive adhesive film 10, the case where the pressure-sensitive adhesive layer 13 contains an ultraviolet blocking agent will be mainly described.

The transmittance of ultraviolet rays in the laminated body portion of the adhesive film 10 excluding the printing coat layer 12 (in the illustrated configuration, the laminated body composed of the base material 11, the adhesive layer 13 and the release liner 14) is 40% or less. It is preferably present, more preferably 35% or less, still more preferably 30% or less.
As a result, the above-mentioned effects are more prominently exhibited.

<Base material>
The base material 11 has a function of supporting the printing coat layer 12 and the pressure-sensitive adhesive layer 13.

Examples of the constituent material of the base material 11 include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate and polyethylene naphthalate; acetate resins and acrylonitrile-butadiene-styrene copolymer (ABS) resins. Examples thereof include various resin materials such as polystyrene and polyvinyl chloride, and one kind or two or more kinds selected from these can be used in combination.

In particular, the base material 11 is preferably made of a material containing at least one of polyolefin and polyester.

A film made of these materials is easily available, is advantageous from the viewpoint of stable production of the adhesive film 10 and reduction of production cost, and makes the productivity of the adhesive film 10 more excellent. Can be done. It is also advantageous from the viewpoint of improving various properties such as flexibility, strength, and durability of the base material 11.

The base material 11 may contain components other than those described above (other components). Examples of such components include colorants such as dyes and pigments, modifiers, rust inhibitors, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, polymerization inhibitors, and the like. Examples thereof include cross-linking agents, catalysts, plasticizers, antioxidants, leveling agents, thickeners, softeners, dispersants and the like.

The thickness of the base material 11 is not particularly limited, but is preferably 20 μm or more and 300 μm or less, and more preferably 25 μm or more and 200 μm or less.

Further, the base material 11 may be made of a single layer or may be a laminated body having a plurality of layers. Further, the base material 11 may be made of, for example, a functionally graded material whose composition changes in a gradient in the thickness direction.

The ultraviolet transmittance of the base material 11 is not particularly limited, but is preferably 70% or more and 99.5% or less, more preferably 75% or more and 99% or less, and further preferably 80% or more and 98% or less.

<Printing coat layer>
The printing coat layer 12 is a portion to which the ultraviolet curable ink is applied, and has a function of fixing the printed portion by the ultraviolet curable ink.

The printing coat layer 12 is made of a material containing a component having an ultraviolet polymerizable functional group. As a material containing a component having an ultraviolet polymerizable functional group, the polymer as the main agent of the coating coat layer 12 for printing may have an ultraviolet polymerizable government-responsive group, or ultraviolet rays may be obtained separately from the polymer as the main agent. A compound having a polymerizable public response group may be blended. Examples of the compound having an ultraviolet-polymerizable public response group include polyfunctional acrylates such as pentaerythritol triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate. Further, the polymer may contain a crosslinked structure formed by bonding with each other via a crosslinking agent (for example, an isocyanate crosslinking agent or the like).

(Polymer)
The type of the polymer serving as the main agent of the printing coat layer 12 is not particularly limited. The "main agent" means a component that occupies 50% by mass or more of the entire material (hereinafter, also referred to as "coating material") constituting the printing coat layer 12, and is a "polymer". Also includes the concept of oligomers.

Examples of the type of polymer contained in the printing coat layer 12 include polyester, polyolefin, polyamide, polyurethane, polystyrene and the like. Among them, polyester, polyamide, polyurethane and the like are preferable from the viewpoint that it is easy to form a crosslinked structure described later.

Further, the polyester may be a urethane-modified polyester. In the following description, a resin material having an ester bond in the main chain, such as polyester and urethane-modified polyester, is referred to as a polyester resin. Since the polyester-based resin easily reacts with an isocyanate cross-linking agent described later to form a cross-linked structure, the polymer preferably contains a polyester-based resin.

In addition, at least a part of the polymer may have an ultraviolet polymerizable functional group. A polymer having such a structure (hereinafter, also referred to as “ink-reactive polymer”) is, for example, a monomer and / or an oligomer (hereinafter, “single”) at a stage of carrying out a polymerization reaction to form a polymer. (Also referred to as "polymer, etc.") and a compound having an ultraviolet polymerizable functional group are allowed to coexist, and a reaction between the compound and a monomer or the like is generated together with a polymerization reaction of the monomer or the like to form a polymer skeleton. It can be produced by incorporating this compound. Further, the ultraviolet polymerizable functional group may be introduced into the polymer by advancing the reaction with the compound in the mixture containing the polymer and the compound having the ultraviolet polymerizable functional group.

The specific type of the reactive functional group, which is a site that reacts with the cross-linking agent in the above polymer, is not particularly limited, and examples thereof include a hydroxyl group, a carboxyl group, and an amino group. This reactive functional group may be one that is involved in the polymerization reaction of the polymer (that is, one that is involved in the formation of the main chain), or one that is additionally provided (such as one introduced into the side chain). You can do it.

(Ultraviolet polymerizable functional group)
The ultraviolet polymerizable functional group (hereinafter, also referred to as “ink reactive group”) contained in the printing coat layer 12 is a component contained in other compounds (particularly, an ultraviolet curable ink) by irradiating with ultraviolet rays. ), And examples thereof include a functional group containing a vinyl group, a (meth) acryloyl group, and the like.

The ink reactive group has an ethylenically unsaturated bond, although it depends on the type of the ultraviolet curable functional group contained in the ultraviolet curable ink (UV ink) used for forming the printed portion. In the case of a functional group, the ink reactive group is preferably a functional group having an ethylenically unsaturated bond (for example, a vinyl group, a (meth) acryloyl group, etc.), and a (meth) acryloyl group is preferable. More preferred. As a result, the reactivity with the UV ink can be made higher. Further, as the UV ink, those containing a functional group having an ethylenically unsaturated bond as an ultraviolet curable functional group are widely used, so that the adhesive film 10 is suitable for many types of UV inks. It can be made highly versatile.

When the adhesive film 10 to which the UV ink is applied is irradiated with ultraviolet rays, the curing reaction of the UV ink proceeds, and the ultraviolet curable functional group of the UV ink (including the cured product of the UV ink) and the printing coat layer 12 The reaction with the compound containing the ink-reactive group inside proceeds. As a result, a structure in which the curable component of the UV ink and the compound containing the ink reactive group are chemically bonded (covalently bonded) is formed. As a result, the adhesion of the printing portion with the UV ink to the printing coat layer 12 becomes excellent. Further, even if the UV ink shrinks due to curing, peeling at the interface between the UV ink and the printing coat layer 12 is less likely to occur.

(Crosslink structure)
The printing coat layer 12 may have a cross-linked structure in which polymers are cross-linked via a cross-linking agent (for example, an isocyanate cross-linking agent or the like). By having such a crosslinked structure, the hardness of the printing coat layer 12 becomes high, and when the UV ink applied to the printing coat layer 12 is cured, a shrinkage stress acts on the printing coat layer 12. Even if there is, the printing coat layer 12 is less likely to be deformed. Therefore, shear stress is less likely to occur between the printing coat layer 12 and the base material 11, and peeling at these interfaces is less likely to occur. In addition, the water resistance of the printing coat layer 12 is improved, and swelling and peeling are less likely to occur even after contact with water.

Various cross-linking agents can be used to form the cross-linked structure, but when an isocyanate cross-linking agent is used, the isocyanate cross-linking agent preferably contains a polyisocyanate compound having two or more isocyanate groups per molecule. Examples of the polyisocyanate compound include adducts such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate and hexamethylene diisocyanate, biuret and isocyanurates.

(Other ingredients)
The printing coat layer 12 may contain components (other components) other than those described above. Examples of such components include cross-linking accelerators, dyes, colorants such as pigments, rust preventives, fillers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, antistatic agents, plasticizers, and oxidations. Examples include preventive agents, dispersants, leveling agents and the like.

The thickness of the printing coat layer 12 is not particularly limited, but is preferably 80 nm or more and 450 nm or less, and more preferably 100 nm or more and 350 nm or less.

If the print coat layer 12 is too thin, the effect of providing the print coat layer 12 as described above may not be sufficiently exhibited. Further, if the printing coat layer 12 is too thick, problems such as a decrease in the productivity of the adhesive film 10 and a decrease in blocking resistance may occur.

The printing coat layer 12 may be a single layer or a laminated body including a plurality of layers. Further, the printing coat layer 12 may be made of, for example, a functionally graded material whose composition changes in a gradient in the thickness direction.

The ultraviolet transmittance of the printing coat layer 12 is not particularly limited, but is preferably 55% or more and 100% or less, and more preferably 70% or more and 99% or less.

<Adhesive layer>
The pressure-sensitive adhesive layer 13 is a portion that comes into contact with the adherend when the pressure-sensitive adhesive film 10 is attached to the adherend. By having the pressure-sensitive adhesive layer 13, the adhesiveness to the adherend can be improved.

When the pressure-sensitive adhesive film 10 is used as a transparent label, it is preferable that the pressure-sensitive adhesive layer 13 is also transparent.

Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 13 include an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a polyvinyl ether-based pressure-sensitive adhesive. Above all, the pressure-sensitive adhesive layer 13 preferably contains an acrylic pressure-sensitive adhesive.

Thereby, the transparency of the pressure-sensitive adhesive layer 13 can be made more excellent. Further, for example, when the pressure-sensitive adhesive layer 13 contains an ultraviolet-cutting agent as described in detail later, the ultraviolet-cutting agent can be stably and uniformly present in the pressure-sensitive adhesive layer 13, and the pressure-sensitive adhesive layer 13 can be present. It is possible to more effectively prevent other components constituting the above (for example, acrylic adhesive) from being adversely affected by the ultraviolet blocking agent, and to exert the function as the adhesive layer 13 more stably. Can be done.

Hereinafter, the acrylic pressure-sensitive adhesive as an example of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 13 will be described in detail.

(Acrylic adhesive)
Examples of the acrylic pressure-sensitive adhesive include acrylic acid ester homopolymers, copolymers containing two or more acrylic acid ester units, and copolymers of acrylic acid esters and other functional monomers. Those containing at least one selected from them (hereinafter, also simply referred to as "acrylic polymer") are used.

Examples of the acrylic acid ester include (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid octyl ester, and (meth) acrylic acid dodecyl ester.

Examples of the functional monomer include (meth) acrylic acid hydroxyethyl ester, (meth) acrylic acid hydroxypropyl ester, (meth) acrylic acid, (meth) acrylamide, and dimethyl (meth) acrylamide. ..

(UV blocking agent)
The pressure-sensitive adhesive film 10 preferably contains an ultraviolet blocking agent in the pressure-sensitive adhesive layer 13.

Since the pressure-sensitive adhesive layer 13 is not adjacent to the printing coat layer 12, even if the ultraviolet blocking agent contained in the pressure-sensitive adhesive layer 13 bleeds out, the influence on the printing coat layer 12 can be suppressed. Therefore, it is possible to appropriately cut ultraviolet rays and make the transmittance of the adhesive film 10 sufficiently small as described above, while effectively preventing the occurrence of problems due to bleed-out of the ultraviolet blocking agent.

The ultraviolet blocking agent is not particularly limited as long as it can block at least a part of ultraviolet rays, and may be, for example, an ultraviolet absorbing agent that absorbs ultraviolet rays or an ultraviolet reflecting agent that reflects ultraviolet rays. ..

As the organic UV absorber, for example, benzophenone-based, benzotriazole-based, benzoate-based, benzoxazine-based, triazine-based, phenylsalicylate-based, cyanoacrylate-based, salicylic acid-based, nickel complex salt-based UV absorbers are used. can do. Of these, benzotriazole-based, benzophenone-based, triazine-based, salicylic acid-based, and cyanoacrylate-based UV absorbers are preferable.

Examples of the inorganic ultraviolet blocking agent (ultraviolet absorber and ultraviolet reflecting agent) include iron oxide, magnetite, titanium oxide (titanium white), zinc oxide and the like, and zinc oxide having a wide wavelength range of ultraviolet rays that can be cut can be used. Is preferable.
Further, as the inorganic ultraviolet reflecting agent, various metal powders can be used.

The inorganic ultraviolet blocking agent may be surface-treated with, for example, potassium stearate, lauric acid, silicone oil, or the like. This makes it possible to improve the dispersibility of the inorganic ultraviolet blocking agent.

When the ultraviolet blocking agent is contained in the pressure-sensitive adhesive layer 13 in a dispersed state, the average particle size of the ultraviolet blocking agent is preferably 0.1 μm or less, and more preferably 0.05 μm or less.
Thereby, the transparency of the pressure-sensitive adhesive layer 13 can be made more excellent.

The content of the ultraviolet blocking agent in the pressure-sensitive adhesive layer 13 is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 0.2% by mass or more and 10% by mass or less.

If the content of the ultraviolet blocking agent is less than the lower limit, it may be difficult to sufficiently block the ultraviolet rays depending on the thickness of the pressure-sensitive adhesive layer 13 and the type of the ultraviolet blocking agent.

On the other hand, if the content of the ultraviolet blocking agent exceeds the upper limit, the transparency of the pressure-sensitive adhesive layer 13 may decrease depending on the thickness of the pressure-sensitive adhesive layer 13, the type of the ultraviolet-cutting agent, and the like.

The pressure-sensitive adhesive layer 13 may contain components (other components) other than those described above. Examples of such components include tackifiers, antioxidants, plasticizers, silane coupling agents, fillers, dyes, colorants such as pigments, dispersants, emulsifiers and the like.

The thickness of the pressure-sensitive adhesive layer 13 is not particularly limited, but is preferably 1 μm or more and 200 μm or less, more preferably 5 μm or more and 100 μm or less, and further preferably 20 μm or more and 60 μm or less.

The ultraviolet transmittance of the pressure-sensitive adhesive layer 13 is not particularly limited, but is preferably 1% or more and 50% or less, more preferably 2% or more and 45% or less, and 3% or more and 40% or less. More preferred.

<Peeling liner>
The release liner 14 has a function of protecting the pressure-sensitive adhesive layer 13 during transportation, storage, and the like of the pressure-sensitive adhesive film 10.

The release liner 14 is not particularly limited, and one usually used in the field of adhesive film can be used. Examples of the release liner include those provided with a release layer on the surface of a paper substrate or a film substrate.

Examples of the paper base material include papers such as high-quality paper, kraft paper, and glassine paper. Examples of the film base material include films made of various resins such as polyethylene terephthalate, polyethylene, and polypropylene. The paper base material and the film base material may contain a filler such as a filler.

When a paper base material is used, ultraviolet rays are usually cut by the paper base material, so that the problem of deterioration of the printing coat layer 12 due to the above-mentioned ultraviolet rays does not occur, but the adhesive film 10 is a transparent label. When used as a release liner 14, a transparent sheet is often used as the release liner 14. Further, when a paper base material is used, problems such as roughening of the film surface are likely to occur because the texture of the paper base material is reflected. Therefore, as the release liner 14, a transparent film base material is preferably used, and a polyethylene terephthalate film is more preferable.

Examples of the constituent material of the release layer include silicone, long-chain alkyl-based resin, fluororesin, and the like.

The thickness of the release liner 14 is not particularly limited, but is preferably 10 μm or more and 150 μm or less, more preferably 20 μm or more and 130 μm or less, and further preferably 35 μm or more and 50 μm or less.

The ultraviolet transmittance of the release liner 14 is not particularly limited, but is preferably 40% or more and 100% or less, and more preferably 70% or more and 99% or less.

[Manufacturing method of adhesive film]
Next, a method for manufacturing the adhesive film 10 as described above will be described.
The adhesive film 10 is manufactured, for example, by the following steps.

That is, for example, the adhesive film 10 has a printing coat layer forming step of forming the printing coat layer 12 on one surface (first surface) of the base material 11 and the other surface (second surface) of the base material 11. It can be suitably manufactured by a method having a pressure-sensitive adhesive layer forming step of forming the pressure-sensitive adhesive layer 13 on the surface) and a coating step of coating the pressure-sensitive adhesive layer 13 with the release liner 14.

<Printing coat layer forming process>
In the printing coat layer forming step, the printing coat layer 12 is formed on one surface (first surface) of the base material 11.

Prior to this step, the base material 11 has a corona treatment or the like on one or both sides for the purpose of improving the adhesion to the layers (printing coat layer 12 and the pressure-sensitive adhesive layer 13) provided on the surface thereof. Surface treatment may be applied.

The method for forming the print coat layer 12 is not particularly limited, but for example, a coating liquid for forming the print coat layer 12 is prepared, and a roll coat, a gravure coat, a reverse coat, a spray coat, a knife coat, and a die coat are prepared. , A method of applying a coating liquid to one surface side of the base material 11 by various coating methods such as bar coating and drying the coating film of the coating liquid.

<Adhesive layer forming process>
In the pressure-sensitive adhesive layer forming step, the pressure-sensitive adhesive layer 13 is formed on the other surface (second surface) of the base material 11.

For the pressure-sensitive adhesive layer 13, for example, a coating liquid containing a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 13 is applied to a surface of the base material 11 opposite to the surface on which the printing coat layer 12 is formed. It can be formed by.

The method for forming the pressure-sensitive adhesive layer 13 is not particularly limited, but for example, a coating liquid for forming the pressure-sensitive adhesive layer 13 is prepared, and a roll coat, a gravure coat, a reverse coat, a spray coat, a knife coat, a die coat, etc. Examples thereof include a method of applying a coating liquid to the other surface (second surface) of the base material 11 by various coating methods such as bar coating and drying the coating film of the coating liquid.

At this time, for example, by incorporating an ultraviolet blocking agent in a predetermined ratio in the coating liquid for forming the pressure-sensitive adhesive layer 13, the pressure-sensitive adhesive film 10 having a transmittance of a predetermined value or less can be preferably obtained. can.

<Coating process>
In the coating step, the surface of the pressure-sensitive adhesive layer 13 (the surface opposite to the surface facing the base material 11) is coated with the release liner 14.

As a result, the pressure-sensitive adhesive layer 13 is suitably protected, and for example, it is possible to more effectively prevent foreign matter from adhering to the pressure-sensitive adhesive film 10 during transportation or storage, or sticking to an undesired portion.

[Flexographic printing machine]
Next, a flexographic printing machine as an example of a printing machine that prints on the adhesive film 10 as described above will be described.
FIG. 2 is a schematic configuration diagram showing an example of the configuration of a printing machine (flexographic printing machine).

The flexographic printing machine 20 shown in FIG. 2 includes a unwinding roll 21 for mounting an adhesive film 10 wound in a roll shape, which is an object to be printed, and a winding roll 28 for winding the adhesive film 10 after printing. , Flexographic printing is performed on the adhesive film 10 continuously supplied from the unwinding roll 21.

As shown in FIG. 2, the flexographic printing machine 20 has an ink pan (ink storage unit) 22 for storing ink (UV ink) and a rotatable anilox roll 23 arranged so as to be immersed in the ink in the ink pan 22. And have. Further, the rotatable plate cylinder 24 having the flexographic plate 24a on the outer peripheral surface is arranged so as to come into contact with the anilox roll 23.

Further, a doctor blade 25 for scraping off excess ink or the like adhering to the surface of the anilox roll 23 is arranged so that the tip thereof comes into contact with the outer peripheral surface of the anilox roll 23.

Further, a rotatable impression cylinder 26 is installed so as to press-contact with the plate cylinder 24 and form a nip portion N between the plate cylinder 24 and the plate cylinder 24.

Printing is performed on the pressure-sensitive adhesive film 10 by transferring the ink adhering to the plate cylinder 24 to the pressure-sensitive adhesive film 10 at the nip portion N.

Further, the flexographic printing machine 20 includes an ultraviolet irradiation lamp 27 that cures the UV ink applied on the adhesive film 10.

In the case of multicolor printing, a printing unit as described above is provided for each color, but only one unit is shown in the figure.

When printing on the adhesive film 10 (flexographic printing) using such a flexographic printing machine 20, the roll-shaped adhesive film 10 attached to the unwinding roll 21 is unwound and pressed against the plate cylinder 24. The adhesive film 10 is set in the printing machine by passing paper to the take-up roll 28 via the nip portion N between the body 26 and the body 26. Normally, about three turns of the roll are used for this paper, and printing is not performed on this portion.

Then, when the anilox roll 23, the plate cylinder 24, and the impression cylinder 26 are rotated in the directions of the arrows in FIG. 2, the ink first adheres to the outer peripheral surface of the anilox roll 23 immersed in the ink in the ink pan 22. Then, the ink on the outer peripheral surface of the anilox roll 23 is further transferred to the outer peripheral surface of the plate cylinder 24, that is, the flexographic plate 24a. At this time, the ink is transferred to the image portion which is the raised portion of the flexographic plate 24a, but the ink is not transferred to the non-image portion which is the recessed portion.

On the other hand, for example, the adhesive film 10 continuously unwound from the unwinding roll 21 is sent to the nip portion N formed between the plate cylinder 24 and the impression cylinder 26. Printing is started after the portion that has been drawn out when the adhesive film 10 is set has passed. The adhesive film 10 is sandwiched between the plate cylinder 24 and the impression cylinder 26, and the ink on the outer peripheral surface of the plate cylinder 24 is transferred to the adhesive film 10. Specifically, the ink adhering to the convex image portion (convex portion) of the flexographic plate 24a of the plate cylinder 24 is transferred to the adhesive film 10.

The printed adhesive film 10 is irradiated with ultraviolet rays by an ultraviolet irradiation lamp 27 to cure the ink.

At this time, when the ink-reactive group contained in the printing coat layer 12 of the adhesive film 10 reacts with the ink (UV ink) by irradiation with ultraviolet rays, the ink reaction component chemically bonds with the cured ink. As a result, the cured ink has improved adhesion to the printing coat layer 12, and even if the ink shrinks due to curing, peeling at the interface between the ink and the printing coat layer 12 is less likely to occur.

In particular, according to the pressure-sensitive adhesive film 10 according to the present invention, even when the adhesive film 10 is stored in the form of a roll for a long period of time, the component having an ultraviolet polymerizable functional group contained in the printing coat layer 12 is not affected by ultraviolet rays. Since the intentional reaction is suppressed, the adhesion between the printing coat layer 12 and the ink at the time of printing can be surely sufficiently excellent.

The printed adhesive film 10 is wound on a winding roll 28.
The printed adhesive film 10 is subjected to various treatments such as cutting to cut it to a desired length, if necessary.

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

For example, in the above description, a case where printing is performed on an adhesive film by flexographic printing has been described as an example, but the present invention is not limited to this, and printing is performed using an ultraviolet curable ink. , May be applied to other printing methods.

Further, the pressure-sensitive adhesive film of the present invention may be provided with a base material, a coating layer for printing, a pressure-sensitive adhesive layer, and a release liner, and further has another structure (for example, at least one intermediate layer). You may be prepared.

Further, in the above-described embodiment, the pressure-sensitive adhesive film of the present invention has been described with an example of a manufacturing method, but the pressure-sensitive adhesive film of the present invention may be manufactured by any method.

Further, in the above-described embodiment, the case where the pressure-sensitive adhesive layer is formed after the printing coat layer is formed on the base material has been typically described, but the printing coat layer is formed after the pressure-sensitive adhesive layer is formed. It may be formed.

Further, in the above-described embodiment, the case where the pressure-sensitive adhesive layer is formed on the base material and then coated with the release liner has been typically described. For example, the pressure-sensitive adhesive layer is formed on the release liner and the release liner is used. The pressure-sensitive adhesive layer formed above may be attached to the substrate.

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

[1] Production of Adhesive Film (Example 1)
(Preparation of coating liquid for printing coat layer)
As a polymer constituting the resin composition, 100 parts by mass of a urethane-modified polyester resin having a hydroxyl group (hydroxyl value 2 mgKOH / g, number average molecular weight 40,000), 10 parts by mass of pentaerythritol triacrylate as an ink reaction component, and isocyanate. A coating liquid having a solid content of 1.5% was prepared by mixing with 20 parts by mass of a cross-linking agent (Coronate HX manufactured by Tosoh Corporation) and diluting with toluene.

(Preparation of adhesive composition)
100 parts by mass of an acrylic copolymer (mass ratio (BA: AA) = 90:10, weight average molecular weight 550,000) obtained using butyl acrylate (BA) and acrylic acid (AA), and an isocyanate cross-linking agent. (Tosoh Co., Ltd., Coronate L) 0.5 parts by mass and 0.3 parts by mass of a benzotriazole-based ultraviolet absorber as an ultraviolet blocking agent are mixed, diluted with methyl ethyl ketone, and a pressure-sensitive adhesive composition having a solid content concentration of 30%. I got something.

(Manufacturing of adhesive film)
A biaxially stretched polypropylene film having a thickness of 50 μm was prepared as a base material, and both surfaces thereof were subjected to corona treatment.

The coating liquid for a printing coat layer is applied to one surface of the substrate by bar coating and dried at 70 ° C. for 1 minute to form a printing coat layer having a thickness of 60 nm made of a resin composition. did.

Further, the prepared pressure-sensitive adhesive composition was applied to the other surface of the substrate at a coating thickness of 25 μm using a roll coater, dried at 80 ° C., and peeled with silicone as a peeling liner. After laminating a 38 μm polyethylene terephthalate (PET) film, the laminate was wound into a roll.

Then, the laminated body wound in a roll shape was further cured under the conditions of 23 ° C. and 50% relative humidity for 7 days, and the printing coat layer, the base material, the adhesive layer and the release liner were laminated in this order. I got an adhesive film.

(Examples 2 and 3)
An adhesive film was produced in the same manner as in Example 1 above, except that the ultraviolet transmittance was changed to the value shown in Table 1 by changing the content of the ultraviolet blocking agent.

(Examples 4 and 5)
The above-mentioned Examples except that the type of the ultraviolet blocking agent was changed as shown in Table 1 and the content of the ultraviolet blocking agent was changed so that the ultraviolet transmittance became the value shown in Table 1. An adhesive film was produced in the same manner as in 1.

(Comparative Example 1)
A pressure-sensitive adhesive film was produced in the same manner as in Example 1 above, except that the pressure-sensitive adhesive layer composition did not contain an ultraviolet blocking agent.

(Comparative Example 2)
An adhesive film was produced in the same manner as in Example 1 above, except that the ultraviolet transmittance was changed to the value shown in Table 1 by changing the content of the ultraviolet blocking agent.

Table 1 summarizes the main conditions of the pressure-sensitive adhesive films of each of the above-mentioned Examples and Comparative Examples. In addition, Table 1 also shows the ultraviolet transmittance (average transmittance in the wavelength range) in the wavelength range of 300 nm or more and 380 nm or less for the pressure-sensitive adhesive films of each of the Examples and Comparative Examples. The ultraviolet transmittance was measured using an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, model name "UV-3600"). Further, in each of the above examples, the content of the ultraviolet blocking agent in the pressure-sensitive adhesive layer was 0.2% by mass or more and 10% by mass or less.

[2] Evaluation [2-1] Ink Adhesion Evaluation After irradiation with ultraviolet rays, the ink adhesion of the printing coat layer was evaluated for the fourth adhesive film from the top.

For the adhesive films of each of the Examples and Comparative Examples, four A4 size sheets were cut out, and these four sheets were laminated so that the printing coat layer faced upward and no gap was formed between the sheets. did. In this state, an ultraviolet fade meter U48 (manufactured by Suga Test Instruments Co., Ltd.) was used to accelerate irradiation with ultraviolet rays for 40 hours in a light resistance test based on JIS B7751-2007.

Then, for the fourth sheet from the top, the release liner was removed, and the exposed adhesive layer was attached to the surface of the rolled film. After that, the film to which the sheet is attached is set in a flexo printing machine, and a predetermined pattern is printed on the printing coat layer surface of the sheet with UV ink (UV flexo white 500 manufactured by T & K TOKA) and irradiated with ultraviolet rays. (Metal halide lamp 4 kW) was performed to form a printed portion, and a printed matter was obtained.

The adhesive film (printed matter) on which the printed portion was formed was allowed to stand for 24 hours in an environment of 23 ° C. and a relative humidity of 50%. After that, based on the cross-cut method of JIS K5600-5-6: 1999 (ISO 2409: 1992), the cut interval is 1 mm and the cut lines are 11 x 11 on the surface of the adhesive film (printed matter) on the side where the printed portion is formed. A cross-cut portion having 100 squares was prepared as a book, and the adhesion between the printed portion and the adhesive film was evaluated.

Specifically, a cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. was attached to the cross-cut portion, the number of squares remaining after the tape was peeled off was set to x, and the residual ratio was obtained as x / 100, which was evaluated according to the following criteria. ..

A: The value of the survival rate (x / 100) is 95/100 or more.
B: The value of the residual ratio (x / 100) is 90/100 or more and less than 95/100.
C: The value of the residual ratio (x / 100) is 80/100 or more and less than 90/100.
D: The value of the residual ratio (x / 100) is 70/100 or more and less than 80/100.
E: The value of the survival rate (x / 100) is less than 70/100.
These results are shown in Table 2.

As is clear from Table 2, in the comparative example, the ink adhesion (adhesion of the printed portion) to the printing coat layer has decreased after the ultraviolet-promoted irradiation, whereas in the present invention, the ultraviolet-promoted. Even after irradiation, the ink adhesion to the printing coat layer (adhesion of the printed portion) was sufficiently maintained.

10 ... Adhesive film 11 ... Base material 12 ... Printing coat layer 13 ... Adhesive layer 14 ... Peeling liner 20 ... Flexographic printing machine 21 ... Unwinding roll 22 ... Ink pan 23 ... Anilox roll 24 ... Plate cylinder 24a ... Flexographic plate 25 ... Doctor blade 26 ... Impressor 27 ... Ultraviolet irradiation lamp 28 ... Winding roll N ... Nip

Claims (10)

An adhesive film used for printing using UV curable ink.
With the base material
A printing coat layer provided on the first surface side, which is one surface of the base material, and made of a material containing a component having an ultraviolet polymerizable functional group.
An adhesive layer provided on the second surface side, which is a surface opposite to the first surface of the base material, and
A release liner that protects the adhesive layer is provided .
It is stored in a rolled state and is stored.
The ultraviolet polymerizable functional group reacts with the ultraviolet curable functional group of the ultraviolet curable ink by being irradiated with ultraviolet rays after the ultraviolet curable ink is applied.
An adhesive film characterized in that the transmittance of ultraviolet rays of the adhesive film is 40% or less. The adhesive film according to claim 1, wherein the laminated body portion of the adhesive film other than the printing coat layer contains an ultraviolet blocking agent. The pressure-sensitive adhesive film according to claim 2, wherein the pressure-sensitive adhesive layer contains the ultraviolet-blocking agent. The pressure-sensitive adhesive film according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive. The pressure-sensitive adhesive film according to any one of claims 1 to 4, wherein the base material is made of a material containing at least one of polyolefin and polyester. A method for producing an adhesive film according to any one of claims 1 to 5.
A printing coat layer forming step of forming a printing coat layer on one surface of a base material using a coating liquid containing a material containing a component having an ultraviolet polymerizable functional group.
A method for producing a pressure-sensitive adhesive film, which comprises a pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer on the other surface of the base material. The method for producing an adhesive film according to claim 6, wherein the printing coat layer forming step is performed prior to the pressure-sensitive adhesive layer forming step. The method for producing an adhesive film according to claim 6, wherein the printing coat layer forming step is performed after the pressure-sensitive adhesive layer forming step. The method for producing an adhesive film according to any one of claims 6 to 8, wherein the coating liquid is not irradiated with ultraviolet rays after being applied. The ultraviolet curable ink applying step of applying the ultraviolet curable ink onto the printing coat layer of the adhesive film according to any one of claims 1 to 5.
By irradiating the ultraviolet curable ink applied on the printing coat layer with ultraviolet rays, the curing reaction of the ultraviolet curable ink is promoted, and the ultraviolet curable functional group of the ultraviolet curable ink and the printing are performed. A method for producing a printed matter, which comprises an ultraviolet irradiation step of advancing a reaction with an ultraviolet polymerizable functional group in a coating layer for printing.

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