WO2011052626A1

WO2011052626A1 - Shrink label

Info

Publication number: WO2011052626A1
Application number: PCT/JP2010/069038
Authority: WO
Inventors: 卓荒井; 彰宮崎
Original assignee: 株式会社フジシールインターナショナル
Priority date: 2009-10-30
Filing date: 2010-10-27
Publication date: 2011-05-05
Also published as: JP2011095602A; JP5513847B2

Abstract

Provided is a shrink label having a printed layer that has good following characteristics with respect to shrink treatment and is tack-free. Said shrink label is characterized by having a printed layer on at least one surface of a base material, said printed layer including an acrylic polymer formed from a monomer component that contains at least 80 wt% of a monofunctional monomer and at least 50 wt% of a monomer selected from a group comprising acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, p-cumyl phenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropylacrylate.

Description

Shrink label

The present invention relates to a shrink label. More specifically, the present invention relates to a shrink label having a printed layer made of an acrylic polymer that has excellent followability and tack-free property during shrink processing.

Currently, plastic bottles such as PET bottles and metal bottles such as bottle cans are widely used as beverage containers for tea and soft drinks. These containers are often equipped with plastic labels for display, decoration, and functionality. These plastic labels have decorativeness, workability (followability to containers), wide display area, etc. In view of merits, shrink labels provided with a printed layer are widely used.

As a printing ink for forming a printing layer of a plastic label, an active energy ray curable printing ink that is cured by an active energy ray such as ultraviolet (UV) has been used in recent years. Furthermore, among them, there are many radically polymerizable active energy ray-curable printing inks that are cured by radical polymerization to form a printing layer because of their comparatively low cost and not being hindered by water polymerization. In particular, radically polymerizable active energy ray-curable printing inks mainly composed of acrylic resins are used (see Patent Document 1).

However, the above radical polymerizable active energy ray curable printing ink uses a relatively large amount of a polyfunctional monomer as a monomer component in order to obtain sufficient curability, and forms a hard printed layer with a high degree of crosslinking after curing. . For this reason, when such a printed layer is used for a shrink label (particularly a highly shrinkable shrink label), the printed layer cannot follow the shrinkage deformation of the shrink film as a base material during shrink processing, and the printed layer is whitened. There has been a problem that causes poor tracking performance.

In response to such a problem, a shrink label is known in which urethane acrylate is added to the printing ink to improve the processing followability of the printed layer (see Patent Document 2).

JP 2002-371217 A International Publication No. 2009/011256 Pamphlet

However, when a printing layer formed from a printing ink added with the above urethane acrylate is also used for a shrink label having a very high shrinkage (for example, a shrinkage rate of about 50%), the followability to shrink processing is Insufficient followability may occur. On the other hand, if the proportion of the monofunctional monomer in the monomer component is increased in order to further improve the followability, the curability of the printing ink decreases, and the uncured monomer remains in the printed layer. There was a problem that the surface tack) remained. Therefore, the present situation is that a shrink label having a good printed layer with good tack-free property and good tack-free property even with high shrinkage shrinkage and no tack or weak tack.

That is, an object of the present invention is to provide a shrink label having a printed layer excellent in both followability to shrink processing and tack-free property.

As a result of intensive studies to achieve the above object, the present inventors have formed a monomer component containing a monofunctional monomer as a main component and containing a specific monomer in a specific ratio on at least one side of the substrate. It was found that by providing a printing layer made of an acrylic polymer (formed by polymerization), it is possible to obtain a shrink label having a printing layer that has both excellent followability to shrink processing and tack-free properties, and completed the present invention. did.

That is, the present invention contains at least 80% by weight of a monofunctional monomer on at least one side of a substrate, and acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy- There is provided a shrink label comprising a printing layer containing an acrylic polymer formed from a monomer component containing 50% by weight or more of a monomer selected from the group consisting of 3-phenoxypropyl acrylate.

Furthermore, the present invention provides the shrink label as described above, wherein the monomer component contains 5 to 90% by weight of acryloylmorpholine.

Furthermore, the present invention provides the shrink label as described above, wherein the monomer component contains 5 to 90% by weight of N-acryloyloxyethyl hexahydrophthalimide.

Furthermore, the present invention provides the shrink label, wherein the printing layer is a printing layer formed by active energy ray curing.

The shrink label of the present invention uses an acrylic polymer formed from a monomer component containing 80% by weight or more of a monofunctional monomer as the acrylic polymer constituting the printed layer. The followability to the deformation of the base material at the time (followability to shrink processing) is good. The monomer component forming the acrylic polymer may be selected from the group consisting of acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropyl acrylate. Thus, the printed layer has no tack (surface tack) or has very low tack (surface tack) and is excellent in tack-free property.
As described above, the shrink label of the present invention is excellent in the followability to the shrink processing of the printed layer and tack-free, and is particularly suitable as a highly shrinkable shrink label.

In this specification, “excellent tack-free” includes not only the case where there is no tack on the surface of the printing layer but also the case where tack is extremely weak.

The shrink label of the present invention contains 80% by weight or more of a monofunctional monomer on at least one side of a base material, and acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy It has a printing layer containing an acrylic polymer formed from a monomer component containing 50% by weight or more of a monomer selected from the group consisting of -3-phenoxypropyl acrylate. The above print layer may be referred to as “print layer of the present invention”. Further, the above acrylic polymer may be referred to as “the acrylic polymer of the present invention”. Furthermore, a monomer selected from the group consisting of the above acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropyl acrylate may be referred to as a “specific monomer”. . 2 selected from the group consisting of acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropyl acrylate in the monomer component forming the acrylic polymer of the present invention. When the above monomers are included, all the monomers are “specific monomers”. The specific monomer is included in the monofunctional monomer.

[Print layer of the present invention]
The printed layer of the present invention is an essential printed layer in the shrink label of the present invention. The printing layer of the present invention contains the acrylic polymer of the present invention as an essential component. Moreover, the printing layer of this invention may contain color materials (coloring agents), such as a cellulose resin and a pigment, and another additive.

The content of the acrylic polymer of the present invention in the total weight (100% by weight) of the printed layer of the present invention varies depending on the content of the pigment and the like and is not particularly limited, but is preferably 30 to 99% by weight, Preferably, it is 45 to 95% by weight.

(Acrylic polymer of the present invention)
The acrylic polymer of the present invention is a polymer formed from a monomer component containing 80% by weight or more of a monofunctional monomer and 50% by weight or more of the specific monomer. In other words, in the acrylic polymer of the present invention, 80% by weight or more of all constituent monomer units constituting the acrylic polymer is a constituent unit derived from a monofunctional monomer, and 50% by weight or more of all constituent monomer units. Is a polymer that is a structural unit derived from a specific monomer. In this specification, “acrylic polymer” means a polymer of monomer components containing (meth) acrylic acid (acrylic acid and / or methacrylic acid) and / or a derivative thereof, that is, a (meth) acryloyl group. The polymer of the monomer component containing the monomer which has is meant. “(Meth) acryl” means “acryl” and / or “methacryl”.

The monofunctional monomer is a monomer having only one radical polymerizable functional group in the molecule. The radical polymerizable functional group is preferably an ethylenically unsaturated group (radical polymerizable ethylenically unsaturated group), more preferably an active energy ray polymerizable radical polymerizable ethylenically unsaturated group (active energy ray radical polymerization). Ethylenically unsaturated group). More specifically, for example, vinyl group, propenyl group, isopropenyl group, (meth) acryloyl group and the like can be mentioned. Examples of the monofunctional monomer include known ethylenically unsaturated monofunctional monomers, and are not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth ) Isopropyl acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate (Meth) acrylic acid alkyl esters having a linear or branched alkyl group such as 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate [preferably (meth) acrylic acid C _1-12 alkyl ester, etc.]; (meth) acrylic acid, black Carboxyl group-containing polymerizable unsaturated compounds such as acid, itaconic acid, fumaric acid, maleic acid or the like; 2-hydroxymethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meta ) Acrylate, 6-hydroxyhexyl (meth) acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate and other hydroxyl group-containing (meth) acrylate [preferably hydroxy (meth) acrylate C _{1- 8} alkyl ester, etc.]; (meth) cyclohexyl acrylate (meth) acrylic acid cycloalkyl ester having an alicyclic hydrocarbon group such as isobornyl (meth) acrylate (meth) acrylic acid ester; phenyl (meth) (Meth) acrylic acid ester having an aromatic hydrocarbon group such as relate and phenoxyethyl (meth) acrylate; N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide (Meth) acrylic acid amide derivatives such as N, N-diethyl (meth) acrylamide; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) (Meth) acrylic acid dialkylaminoalkyl esters such as acrylate and dipropylaminopropyl (meth) acrylate; styrene compounds such as styrene, vinyltoluene and α-methylstyrene; vinyl acetate and propionic acid Vinyl esters such as alkylsulfonyl; vinyl ethers such as methyl vinyl ether; vinyl halides such as vinyl chloride (meth) cyano group-containing vinyl compounds such as acrylonitrile, ethylene, etc. olefins such as propylene. The specific monomer is also included in the monofunctional monomer.

Among these, the monofunctional monomer is preferably a monofunctional monomer having a primary irritation index (PII) value of 2.5 or less according to OECD 404 from the viewpoint of safety, and a monofunctional monomer having a PII value of 2.0 or less. Monomers are more preferred.

Monofunctional monomers other than the specific monomer include isobornyl acrylate (PII value: 0.6), phenoxyethyl acrylate (PII value: 0.5), nonylphenol EO modified acrylate (PII value: 2.0), 4-acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane (PII value: 0.55) is preferred.

The above nonylphenol EO-modified acrylate is represented by the following formula.

In the above formula, m is the average added mole number of ethylene oxide and is not particularly limited, but is preferably about 1.

The content of the monofunctional monomer in the total amount (100% by weight) of the monomer components forming the acrylic polymer of the present invention is 80% by weight or more (80 to 100% by weight), preferably 85 to 99% by weight. is there. In addition, content of a specific monomer is also contained in content of said monofunctional monomer. By setting the content of the monofunctional monomer to 80% by weight or more, the acrylic polymer of the present invention becomes relatively flexible, and the followability to the shrink processing of the printed layer of the present invention is improved. When the content of the monofunctional monomer is less than 80% by weight, that is, 20% by weight of the polyfunctional monomer having two or more radically polymerizable functional groups in the molecule in the total amount of the monomer components forming the acrylic polymer of the present invention. If it is contained in an amount of at least%, the acrylic polymer of the present invention becomes hard, and the followability of the printed layer of the present invention to shrink processing decreases.

The specific monomers (acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO modified acrylate, 2-hydroxy-3-phenoxypropyl acrylate) that form the acrylic polymer of the present invention are highly reactive. When the acrylic polymer is cured (polymerized) to form an acrylic polymer and a printed layer made of the acrylic polymer is formed, the uncured (unreacted) residual monomer is reduced in the printed layer. Moreover, the glass transition temperature (Tg) of the acrylic polymer formed by curing these specific monomers is relatively high. For this reason, the tack of a printing layer can be reduced. Generally, when the proportion of the monofunctional monomer in the monomer component forming the acrylic polymer increases, the reactivity decreases, and the printed layer made of the acrylic polymer tends to have a large tack. However, in the present invention, by adding a specific amount of the above specific monomer to the monomer component that forms the acrylic polymer, tack is reduced, and both the followability to the shrink processing of the printed layer and the tack free property are achieved. ing.

The above paracumylphenol EO-modified acrylate (paracumylphenol ethylene oxide-modified acrylate) is represented by the following formula.

In the above formula, n is the number of added moles of ethylene oxide, and is not particularly limited, but is preferably an integer of 1 or 2, and 1 is particularly preferable. The average number of added moles of ethylene oxide is not particularly limited, but is preferably about 1.

The content of the specific monomer in the total amount (100% by weight) of monomer components forming the acrylic polymer of the present invention is 50% by weight or more (50 to 100% by weight), preferably 70 to 100% by weight, more The amount is preferably 80 to 100% by weight, more preferably 85 to 99% by weight. When the content of the specific monomer is less than 50% by weight, the reactivity of the monomer component is low, and the uncured (unreacted) monomer tends to remain in the formed printing layer, or the glass transition of the acrylic polymer after curing. Since the temperature is lowered, the surface tack of the printed layer is increased. The total amount of monomer components forming the acrylic polymer of the present invention is selected from the group consisting of acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropyl acrylate. In the case where two or more specific monomers are included, the total content (total content) of all the specific monomers is the “specific monomer content”.

The specific monomer in the acrylic polymer of the present invention may be used alone or in combination of two or more. From the viewpoint of improving the curability of the printing ink when forming the printing layer, it is preferable to use two or more kinds in combination.

Among the above-mentioned specific monomers, acryloylmorpholine is preferable from the viewpoint of good curing reactivity, higher glass transition temperature of the cured acrylic polymer, and effective in reducing the tack of the printed layer. When acryloylmorpholine is used as the specific monomer, the content of acryloylmorpholine in the total amount (100% by weight) of monomer components forming the acrylic polymer of the present invention is preferably 5 to 90% by weight, more preferably 20 to 80%. % By weight, more preferably 30 to 70% by weight.

As the specific monomer, N-acryloyloxyethylhexahydrophthalimide is also used from the viewpoint of good curing reactivity, higher glass transition temperature of the acrylic polymer after curing, and effective in reducing the tack of the printed layer. preferable. When N-acryloyloxyethyl hexahydrophthalimide is used as the specific monomer, the content of N-acryloyloxyethyl hexahydrophthalimide in the total amount (100% by weight) of the monomer component forming the acrylic polymer of the present invention is 5 to It is preferably 90% by weight, more preferably 20 to 80% by weight, still more preferably 30 to 70% by weight.

If the monomer component forming the acrylic polymer of the present invention is less than 20 wt% [preferably less than 15 wt%, more preferably less than 10 wt%] relative to the total amount (100 wt%) of the monomer component, It may contain a functional monomer. The polyfunctional monomer is a monomer having two or more radical polymerizable functional groups in the molecule.

The above monofunctional monomer and polyfunctional monomer may be used for the polymerization of the acrylic polymer of the present invention in the form of an oligomer. The degree of polymerization of the oligomer is not particularly limited, but is preferably 2 to 20, and more preferably 5 to 15. That is, for example, the monofunctional monomer may be polymerized in advance to obtain an oligomer (monofunctional oligomer) having a polymerization degree of 2 to 20 (more preferably 5 to 15) and then used for the polymerization of the acrylic polymer of the present invention. Good.

(Cellulosic resin)
The printing layer of the present invention may contain a cellulose resin in addition to the acrylic polymer of the present invention. Cellulosic resins exhibit the effect of adjusting the viscosity of a composition for forming a printed layer (sometimes referred to as “printing ink”). When the viscosity of the printing ink is low, the coating property (coating property) can be improved by adding a cellulose resin to increase the viscosity. In addition, since it is non-reactive with the curing reaction of the printing ink (polymerization reaction of the monomer component), it gives the printed layer a certain degree of hardness while maintaining the flexibility of the acrylic polymer, and the surface tack of the printed layer. Demonstrate the effect of reducing. The cellulose-based resin is not particularly limited, but esterified cellulose resins such as nitrocellulose (nitrified cotton), cellulose acetate butyrate (CAB), cellulose acetate, and cellulose acetate propionate (CAP) are preferably exemplified. The Among these, cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) are particularly preferable.

The weight average molecular weight of the cellulose resin is not particularly limited, but is preferably 10,000 to 150,000, and more preferably 20,000 to 100,000. If the weight average molecular weight is less than 10,000, the viscosity of the printing ink may not increase, or the tack reduction effect of the printed layer may not be obtained. On the other hand, if it exceeds 150,000, the solubility of the cellulose resin in the printing ink may deteriorate. In addition, the printing ink may have a too high viscosity and the coating property may deteriorate.

Commercially available products can also be used as the cellulose resin. For example, “CAB-381-20, CAB-381-0.5, CAB-551-0.1, CAP-504-0.2, CAP-482-0.5, etc.” manufactured by Eastman Chemical Co., Bergerac NC's "HIG series" and "LIG series" are available on the market.

The content of the cellulose resin in the printing layer of the present invention is not particularly limited, but is preferably 0 to 20 parts by weight with respect to 100 parts by weight of the acrylic polymer of the present invention. When a cellulose resin is added, the amount is more preferably 1 to 15 parts by weight, still more preferably 2 to 10 parts by weight. When the content of the cellulose resin is less than 1 part by weight, the effect of adjusting the viscosity of the printing ink is insufficient, and the applicability of the printing ink may be lowered. On the other hand, when the amount exceeds 20 parts by weight, the printing ink becomes too viscous and the applicability may be lowered, or the performance of the printing layer may be lowered.

(Coloring material)
The printing layer of the present invention may contain a color material (colorant) for the purpose of coloring or the like. As the coloring material, known or commonly used dyes and pigments used in printing inks can be used, and are not particularly limited, but pigments are preferably used. The pigment may be a known or commonly used organic or inorganic coloring pigment used in printing ink depending on the application, and is not particularly limited. For example, white pigment such as titanium oxide (titanium dioxide), copper Indigo (blue) pigments such as phthalocyanine blue, red pigments such as condensed azo pigments, yellow pigments such as azo lake pigments, carbon black, aluminum flakes, mica (mica), and the like can be selected and used according to the application. In addition, extender pigments such as alumina, calcium carbonate, barium sulfate, silica, and acrylic beads can also be used as pigments for the purpose of adjusting gloss. Only 1 type may be used for the said pigment and it may use 2 or more types together.

The content of the pigment can be arbitrarily designed according to the type of pigment, the concentration of the target color, etc., but is preferably 1 to 50% by weight, more preferably based on the total amount (100% by weight) of the printed layer. 2 to 40% by weight. When two or more kinds of pigments are contained in the printing layer, the total content of all pigments preferably satisfies the above range.

As the titanium oxide when the printing layer of the present invention is used as a white printing layer, any of rutile type (tetragonal high temperature type), anatase type (tetragonal low temperature type), and brookite type (orthogonal crystal) may be used. However, for example, titanium oxide “JR series” manufactured by Teika Co., Ltd. is available. In addition, the content of titanium oxide in the white printed layer is preferably 30 to 50% by weight with respect to the total amount of the printed layer from the viewpoints of concealability and suppression of coarse protrusion formation.

(Other additives)
In addition to the acrylic polymer of the present invention, which is an essential component, and the cellulose resin and color materials (pigments, etc.), which are essential components, the printing layer of the present invention includes the acrylic polymer of the present invention and Resins other than cellulosic resins (sometimes called "other resins"), plasticizers, lubricants, anti-settling agents, dispersants, stabilizers, fillers, antioxidants, ultraviolet absorbers, antistatic agents, colors You may contain additives, such as a parting prevention agent, a fragrance | flavor, and a deodorizing agent, in the range which does not impair the effect of this invention.

Examples of the other resin include a silicone compound (silicone oil) added from the viewpoint of leveling properties of printing ink, defoaming effect, and slipperiness of the printing layer. Although the silicone compound is not particularly limited, a straight silicone compound (dimethylsilicone, methylphenylsilicone, methylhydrogensilicone, etc.) that is a polysiloxane having a main chain composed of a siloxane bond and has no substituent other than a methyl group or a phenyl group. Or a modified silicone compound having a substituent other than a methyl group or a phenyl group at the side chain or terminal. Examples of the substituent in the modified silicone compound include an epoxy group, a fluorine atom, an amino group, a carboxyl group, an aliphatic hydroxyl group (alcoholic hydroxyl group), an aromatic hydroxyl group (phenolic hydroxyl group), and a polyether chain. A substituent etc. are mentioned. Examples of the modified silicone having these substituents include epoxy-modified silicone, fluorine-modified silicone, amino-modified silicone, polyether-modified silicone, carboxyl-modified silicone, carbinol-modified silicone, phenol-modified silicone, and diol-modified silicone. The As these modified silicone compounds, for example, compounds described in International Publication No. 2007/007803 pamphlet can be used. The content of the silicone compound is not particularly limited, but is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight, based on the total amount (100% by weight) of the printed layer.

Examples of the lubricant include polyolefin waxes such as polyethylene wax and polyethylene oxide wax, various waxes such as fatty acid amide, fatty acid ester, paraffin wax, polytetrafluoroethylene (PTFE) wax, and carnauba wax. . The content of the lubricant is not particularly limited, but is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on the total amount (100% by weight) of the printed layer.

(Method for forming printed layer of the present invention, printing ink)
The printing layer of the present invention comprises a polymerizable component [monofunctional monomer including a specific monomer and / or its oligomer (monofunctional oligomer), etc.] that forms the acrylic polymer of the present invention, and a polymerization initiator as necessary. It is formed by applying and curing a composition (printing ink) containing a cellulose resin, a color material (pigment etc.) and other additives. The composition for forming the printing layer may be referred to as “printing ink”.

As the above-described printing ink curing method, known and commonly used ink curing methods such as active energy ray curing and thermal curing can be used. Among these, active energy ray curing is preferable from the viewpoint of suppressing thermal deformation of the shrink film as the base material. Examples of the active energy rays include visible light, ultraviolet rays, and electron beams. Among these, from the viewpoint of productivity, ultraviolet rays are particularly preferable, and near ultraviolet rays are more preferable. A preferred wavelength is 200 to 460 nm. That is, the printing layer of the present invention is preferably a printing layer formed by active energy ray curing (active energy ray curable printing layer), more preferably a printing layer formed by ultraviolet curing (ultraviolet curable printing layer). ).

The printing ink for forming the printing layer of the present invention (sometimes referred to as “printing ink of the present invention”) contains a polymerizable component that forms the acrylic polymer of the present invention as an essential component. The polymerizable component contains the above-mentioned monofunctional monomer and / or monofunctional oligomer, and includes specific monomers (acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy- A monomer selected from the group consisting of 3-phenoxypropyl acrylate) as an essential component.

The monofunctional monomer in the polymerizable component is a monofunctional monomer exemplified as the monofunctional monomer contained in the monomer component forming the acrylic polymer of the present invention. The monofunctional oligomer is a polymer having a low degree of polymerization of the monofunctional monomer. The degree of polymerization is not particularly limited, but is preferably 2 to 20, and more preferably 5 to 15.

In the present specification, the oligomer is a polymer having a low polymerization degree of the monomer component forming the acrylic polymer of the present invention [radically polymerizable functional group (preferably radical polymerizable ethylenically unsaturated group, more preferably Means a polymer polymerized in an active energy ray radically polymerizable ethylenically unsaturated group). In the present specification, among the polymers described above, a polymer having a molecular weight of 10,000 or less (preferably a polymer having a molecular weight of 7000 or less) is referred to as an oligomer.

The content of the polymerizable component in the total weight (100% by weight) of the printing ink of the present invention is not particularly limited, but is preferably 30 to 99% by weight, more preferably 45 to 95% by weight.

The total content of the monofunctional monomer and the monofunctional oligomer in the total amount of the polymerizable component (100 wt%) is preferably 80 wt% or more (80 to 100 wt%), more preferably 85 to 99 wt%. . The total content of the specific monomer in the total amount of the polymerizable component (100% by weight) is preferably 50% by weight or more (50 to 100% by weight), more preferably 70 to 100% by weight, and still more preferably 80%. -100% by weight, most preferably 85-99% by weight.

The polymerizable component may contain a polyfunctional monomer and / or a polyfunctional oligomer. Said polyfunctional monomer is a monomer which has a 2 or more radically polymerizable functional group in a molecule | numerator. The polyfunctional oligomer is a polymer having a low polymerization degree of the polyfunctional monomer. The degree of polymerization is not particularly limited, but is preferably 2 to 20, and more preferably 5 to 15. The total content of the polyfunctional monomer and polyfunctional oligomer in the total amount of the polymerizable component (100% by weight) is less than 20% by weight, preferably less than 15% by weight, and more preferably less than 10% by weight.

In addition to the polymerizable component, the printing ink of the present invention preferably further contains a polymerization initiator (active energy ray polymerization initiator, thermal polymerization initiator, etc.) corresponding to the type of curing reaction. In particular, when the printing layer of the present invention is formed by active energy ray curing, the printing ink of the present invention contains an active energy ray polymerization initiator (sometimes referred to as “photopolymerization initiator”). Is preferred.

The photopolymerization initiator is not particularly limited, but a photoradical polymerization initiator is preferable. The radical photopolymerization initiator is not particularly limited. For example, benzoin, benzoin alkyl ethers, benzyl ketals, acetophenone, α-hydroxycyclohexyl phenyl ketone, acetophenone derivatives, benzyl, benzophenone, benzophenone derivatives, α-acyloxime esters Thioxanthone derivatives, anthraquinone derivatives, aromatic peroxide esters and the like. These may be used alone or in admixture of two or more. The content of the photo radical polymerization initiator is not particularly limited, but is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, based on the total weight (100% by weight) of the printing ink.

Commercially available products can also be used as the photopolymerization initiator, for example, trade names “DAROCUR TPO”, “IRGACURE 184, 651, 2959, 907, 369, 1700, 1800, manufactured by Ciba Specialty Chemicals, Inc. 1850, 819 "," DAROCUR 1173 "and the like.

The printing ink of the present invention may further contain the aforementioned cellulose resin, color material (pigment, etc.) and other additives as necessary.

In the printing ink of the present invention, the content of the solvent used mainly as a dispersant without participating in the reaction is preferably 5% by weight or less, more preferably 1% by weight or less, Most preferably, no solvent is contained. The solvent here refers to, for example, an organic solvent such as toluene, xylene, methyl ethyl ketone, ethyl acetate, methyl alcohol, and ethyl alcohol, and water. In gravure and flexographic printing inks, coating processability and These are usually used for the purpose of improving the compatibility and dispersibility of these components. In addition, the reactive diluent taken in the printed layer after hardening is not included in this. The printing ink of the present invention can exhibit excellent coating properties and dispersibility between components even without a solvent, and can be used without a solvent, or the amount of the solvent can be extremely reduced. Removal is unnecessary, speeding up and cost reduction can be achieved, and the environmental load can be reduced.

The printing ink of the present invention is not particularly limited, but the polymerizable component that forms the acrylic polymer of the present invention, a polymerization initiator, a cellulose resin, a coloring material (pigment, etc.) and other additives as necessary. Each component such as an agent can be blended and mixed. For mixing, mixers such as butterfly mixers, planetary mixers, pony mixers, dissolvers, tank mixers, homomixers, homodispers, paint shakers, roll mills, sand mills, ball mills, bead mills, line mills, and kneaders are used. The mixing time (retention time) during mixing is not particularly limited, but is preferably 10 to 120 minutes. The obtained printing ink may be used after being filtered, if necessary.

The viscosity (23 ± 2 ° C.) of the printing ink of the present invention is not particularly limited. For example, when applied by flexographic printing, it is preferably 10 to 3000 mPa · s, more preferably 20 to 1000 mPa · s. is there. When the viscosity exceeds 3000 mPa · s, the flexographic printability may be reduced, and “decrease” or the like may occur, resulting in a decrease in decorating properties. On the other hand, when the viscosity is less than 10 mPa · s, the storage stability may be deteriorated, for example, the pigment or the additive may easily settle. The viscosity of the printing ink can be controlled by the blending ratio of each blending component, thickener, thinning agent, and the like. In the present specification, “viscosity” is JIS Z under the conditions of 23 ± 2 ° C. and 50 rpm of the cylinder using an E-type viscometer (conical flat plate viscometer) unless otherwise specified. The value measured according to 8803 is meant.

The printing layer of the present invention can be formed by applying the above-described printing ink of the present invention to at least one side of the substrate and curing it.

The above application can be performed using a known and commonly used application method and printing method. Among these, the printing ink of the present invention is preferably applied (coated) by gravure printing, flexographic printing, or inkjet printing from the viewpoints of cost, productivity, printing decoration, and the like.

As described above, the above curing can be performed by a known and commonly used ink curing method, and among them, active energy ray curing (particularly, ultraviolet curing) is preferable. Specifically, for example, an ultraviolet (UV) lamp, an ultraviolet LED, or an ultraviolet laser can be used. The active energy ray to be irradiated varies depending on the composition of the printing ink and is not particularly limited. However, from the viewpoint of curability, ultraviolet rays having a wavelength of 200 to 460 nm (near ultraviolet rays) are preferable, and the integrated light amount is 50 to 2000 (mJ). / Cm ² ) is preferred.

The thickness of the printing layer of the present invention (single layer thickness) is not particularly limited, but is preferably 0.5 to 5 μm, more preferably 1 to 4 μm. If the thickness of the printing layer is less than 0.5 μm, the strength of the printing layer may be weakened. On the other hand, if the thickness exceeds 5 μm, the amount of printing ink used increases, which may be undesirable in terms of cost and environment. Furthermore, when it becomes difficult to apply uniformly, the followability to shrink processing may be reduced, or the printed layer may become brittle and easily peel off. Moreover, when the coloring material (coloring agent) is contained, it becomes difficult to harden to a deep part and it may become easy to peel.

[Base material]
The base material (base material layer) in the shrink label of the present invention serves as a carrier (support) for the printing layer, and is a layer that mainly affects the strength, rigidity and shrinkage characteristics of the label. If the said base material is a shrink film (heat-shrinkable film), it will not specifically limit, The shrink film used as a base material of a well-known shrink label can be used. The type of resin that forms the shrink film can be appropriately selected according to the required physical properties, application, cost, and the like, and is not particularly limited. For example, a polyester resin, a polyolefin resin, a polystyrene resin, Examples of the resin include polyvinyl chloride resin, polyamide resin, aramid resin, polyimide resin, polyphenylene sulfide resin, and acrylic resin. These resins may be used alone or in combination of two or more. Furthermore, the same kind or different kinds of resins may be laminated to be used as a laminated film. Of these, polyester resins, polyolefin resins, and polystyrene resins are preferable. That is, the shrink film includes a polyester film made of a polyester resin, a polystyrene film made of a polystyrene resin, a polyolefin film made of a polyolefin resin, a polyester resin as an outer layer, and a polyolefin resin or a polystyrene resin as an inner layer. The heterogeneous laminated film is preferred. Among the above, a polyester film is particularly preferable from the viewpoint of transparency. Examples of the polyester-based resin, polyolefin-based resin, and polystyrene-based resin include, for example, JP-A-2008-170822, JP-A-2008-170697, JP-A-2008-163215, and JP-A-2008-163231. The polyester resins, polyolefin resins, polystyrene resins, and the like described can be used.

Examples of the polyester resin used for the polyester film include polyethylene terephthalate (PET) resin, poly (ethylene-2,6-naphthalenedicarboxylate) (PEN), polylactic acid (PLA), and the like. Among them, polyethylene terephthalate (PET) resin is preferable. As the PET resin, polyethylene terephthalate (PET) using terephthalic acid as the dicarboxylic acid component and ethylene glycol as the diol component; terephthalic acid as the dicarboxylic acid component, ethylene glycol as the diol component, Copolyester (CHDM copolymerized PET) using 4-cyclohexanedimethanol (CHDM) as a copolymerization component, terephthalic acid as a dicarboxylic acid component, ethylene glycol as a diol component, and neopentyl glycol (NPG) as a main component Copolyester (NPG copolymerized PET) used as copolymer component, terephthalic acid as dicarboxylic acid component, ethylene glycol as main component as diol component, diethylene glycol as copolymer component Diol-modified PET, such as copolymerized polyester; (in the dicarboxylic acid component, modified terephthalic acid as a main component with isophthalic acid and / or adipic acid) the dicarboxylic acid-modified PET, and the like.

Examples of the polystyrene resin used for the polystyrene film include styrene, α-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, p-isobutyl styrene, pt- Examples thereof include resins containing one or more styrene monomers such as butyl styrene and chloromethyl styrene. Specifically, for example, general polystyrene, styrene-butadiene copolymer (SBS), styrene-butadiene-isoprene copolymer (SBIS), styrene-acrylate copolymer, and the like are preferably exemplified.

Examples of polyolefin resins used in the polyolefin film include polyethylene resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and metallocene catalyst LLDPE (mLLDPE), polypropylene, and propylene-α-olefin. Examples include polypropylene resins such as copolymers, ethylene vinyl acetate copolymers, and cyclic olefin resins. In particular, the polyolefin film is preferably one having a cyclic olefin resin as an outer layer. For example, it is preferable to use a cyclic olefin resin as an outer layer and a polyethylene resin or a polypropylene resin as an inner layer (center layer).

The base material in the present invention may have a single layer structure or a laminated structure. That is, the shrink film may be a single layer film or a laminated film in which a plurality of film layers are laminated according to required physical properties, applications, and the like. In the case of a laminated film, film layers made of the same kind of resin may be laminated, or film layers made of different resins may be laminated. In the case of a laminated film, a laminated film having a polyester resin as an outer layer and a polyolefin resin or polystyrene resin as an inner layer, or a laminated film having a cyclic olefin resin as an outer layer and a polyethylene resin or a polypropylene resin as an inner layer is preferable.

The shrink film used as the substrate is preferably a uniaxially, biaxially or multiaxially oriented film from the viewpoint of exhibiting shrinkage characteristics. When the shrink film is a laminated film, it is preferable that at least one film layer in the laminated film is oriented. When all the film layers are non-oriented, sufficient shrink characteristics may not be exhibited. As the shrink film, a uniaxial or biaxially oriented film is often used, and among them, a film that is strongly oriented in the uniaxial direction of the film (substantially uniaxially stretched film) is generally used. It is done. A film uniaxially stretched in the width direction is particularly preferable.

The shrink film can be produced by a conventional method such as melt film formation or solution film formation. It is also possible to use a commercially available shrink film. The surface of the shrink film may be subjected to conventional surface treatment such as corona discharge treatment or primer treatment, if necessary. When a shrink film having a laminated structure is produced, a conventional method such as a co-extrusion method or a dry lamination method can be used as a lamination method. Biaxial stretching in the longitudinal direction (the film production line direction; also referred to as the longitudinal direction or MD direction) and the width direction (the direction perpendicular to the longitudinal direction; also referred to as the transverse direction or TD direction) is used as a method for orienting the shrink film. Uniaxial stretching in the longitudinal direction or the width direction can be used. As the stretching method, any of a roll method, a tenter method, and a tube method may be used. For example, the stretching treatment of the film substantially uniaxially stretched in the width direction is, for example, 1.01 to 1.5 times, preferably 1.05 in the longitudinal direction at a temperature of about 70 to 100 ° C. if necessary. After stretching to about 1.3 times, it can be performed by stretching 3 to 6 times, preferably about 4 to 5.5 times in the width direction.

The shrinkage rate of the shrink film in the main orientation direction at 90 ° C. for 10 seconds (sometimes referred to as “thermal shrinkage rate (90 ° C., 10 seconds)”) is not particularly limited, but is 15 to 80%. Preferably, it is 20 to 75%, more preferably 25 to 70%. The heat shrinkage (90 ° C., 10 seconds) in the direction perpendicular to the main orientation direction is not particularly limited, but is preferably −3 to 15%. The above-mentioned “main orientation direction” is a direction mainly subjected to a stretching process (a direction having the largest thermal shrinkage), and is generally a longitudinal direction or a width direction, for example, substantially in the width direction. In the case of a uniaxially stretched film, it is the width direction.

When the shrink film is a transparent film, the haze value (%) of the shrink film (based on JIS K 7105) is preferably less than 10%, more preferably less than 5.0%, and even more preferably less than 2.0%. . When the haze value is 10% or more, when printing is shown through the shrink film, the printing may become cloudy and the decorativeness may be deteriorated.

The thickness of the substrate is not particularly limited, but is preferably 10 to 100 μm, more preferably 12 to 80 μm, and still more preferably 15 to 60 μm.

Commercially available products can be used as the shrink film used as the base material. For example, “Space Clean S7042” manufactured by Toyobo Co., Ltd., “LX-10S”, “LX-61S” manufactured by Mitsubishi Plastics (hereinafter polyester film); “Bonnset” manufactured by CI Kasei Co., Ltd., Gunze “GMLS” (polystyrene film) manufactured by Gunze Co., Ltd. “FL” (polyolefin film) manufactured by Gunze Co., Ltd. “Ecology” manufactured by Mitsubishi Plastics Co., Ltd. (polylactic acid film); Mitsubishi Plastics Co., Ltd. “DL” manufactured by Gunze Co., Ltd. and “HGS” manufactured by Gunze Co., Ltd. (the above is a laminated film having a polyester resin as a surface layer and a polystyrene resin as a central layer).

[Shrink label]
As described above, the shrink label of the present invention has the printed layer of the present invention on at least one side of the substrate. The printed layer of the present invention is not necessarily provided on the entire surface of the label, and can be provided only on a part of the substrate. Specifically, the printing layer of the present invention each containing a different color material is laminated on the substrate, the printing layer of the present invention is further laminated on the printing layer of the present invention provided on the substrate, Or a desired character and design can be formed by not providing a printing layer in a part. Moreover, the printing layer of this invention may be provided on the base material through the anchor coat layer as needed.

Furthermore, in addition to the base material and the printing layer of the present invention, the shrink label of the present invention includes an adhesive layer, an ultraviolet protection layer, an anchor coating layer, a primer coating layer, and a printing layer other than the printing layer of the present invention (“ A layer such as a nonwoven fabric or paper may be provided as necessary. The other printing layer may be, for example, a printing layer formed from a solvent-based printing ink.

In the shrink label of the present invention, the printed layer of the present invention may be provided so as to be inside the label, or may be provided so as to be outside the label.
Although the lamination structure of the shrink label of the present invention is not particularly limited, for example, from the front side (the front side of the label),
A two-layer laminated structure comprising a substrate / printing layer of the present invention and a printing layer / substrate of the present invention;
Print layer of the present invention / Substrate / Print layer of the present invention, Substrate / Print layer of the present invention / Print layer of the present invention, Print layer of the present invention / Substrate / Print layer of the present invention / Print layer of the present invention , Substrate / other printing layer / printing layer of the present invention, printing layer of the present invention / substrate / other printing layer / printing layer of the present invention, and the like.

In the present specification, the “front side” of the shrink label means the side viewing the design of the label (the side of the surface on which the design looks correct), and the “back side” of the shrink label means the above “front side”. Means the other side. The “outside” of the shrink label means the side that does not contact the container (the side opposite to the container) when the shrink label is attached to the container, and the “inside” of the shrink label contacts the container. Means side (container side).

The shrinkage rate of the shrink label of the present invention in the main orientation direction at 90 ° C. for 10 seconds (heat shrinkage rate (90 ° C., 10 seconds)) is not particularly limited, but is 15% or more (for example, 15 to 80%) ), Preferably 20 to 75%, more preferably 25 to 70%. When the heat shrinkage (90 ° C., 10 seconds) is less than 15%, the followability with respect to the shape of a container or the like to which the label is attached is insufficient during shrink processing, and a beautiful finish may not be obtained. The heat shrinkage (90 ° C., 10 seconds) in the direction perpendicular to the main orientation direction is not particularly limited, but is preferably −3 to 15%. The “main orientation direction” is a direction mainly subjected to a stretching process (a direction having the largest thermal shrinkage rate), and is generally a circumferential direction when the shrink label is a cylindrical shrink label.

In the shrink label of the present invention, the printing ink can be cured by radical polymerization to form a printing layer, so that it does not suffer from polymerization inhibition (curing inhibition) due to moisture unlike a printing layer cured by cationic polymerization. This is also advantageous. For this reason, for example, the printing layer of this invention can also be provided on the printing layer by water-based ink. Furthermore, the printing layer of this invention uses the acrylic polymer formed from the monomer component which has a monofunctional monomer as a main component as an acrylic polymer which comprises a printing layer. For this reason, the printing layer of this invention is excellent in the followability with respect to a shrink process, and whitening of a print layer does not arise also at the time of the high shrinkage shrink process.

In general, when an acrylic polymer is formed from a monomer component containing a monofunctional monomer as a main component, curing is insufficient and uncured monomer remains in the printed layer or has a low glass transition temperature (Tg). Since the acrylic polymer is formed, surface tack (stickiness, adhesiveness) occurs in the printing layer, and there is a tendency that problems such as a decrease in wear resistance and blocking occur. In contrast, in the present invention, the use of a specific amount of a specific monomer capable of forming an acrylic polymer having excellent curability and high Tg in the monomer component forming the acrylic polymer suppresses the tack of the printed layer. And has achieved excellent tack-free properties. As a result, the shrink label of the present invention has both a followability to the shrink processing of the printed layer and a tack-free property.

The shrink label of the present invention is not particularly limited, such as a cylindrical label, a wound label, and the like, but from the viewpoint of sufficiently exhibiting the effect of excellent followability to shrink processing, a tubular shrink label (cylindrical shrink label) is preferable.

The shrink label of the present invention is generally used as a labeled container by placing it on the container by heat-shrinking it with the front side facing away from the container. Such containers include, for example, soft drink bottles such as PET bottles, milk containers for home delivery, food containers such as seasonings, alcohol beverage bottles, pharmaceutical containers, containers for chemical products such as detergents and sprays, cups, etc. This includes noodle containers. Also, the material of the container includes plastic such as PET, glass, metal and the like. In addition, the shrink label of this invention may be used for adherends other than a container.

In the shrink label of the present invention, the printing ink of the present invention is applied on the surface of at least one side of the substrate (shrink film) according to the above-described method for forming a printed layer of the present invention, and the printed layer is formed by curing. By providing, it can produce. The above coating and curing steps may be performed during the shrink film manufacturing process (in-line coating) or after film formation (off-line coating), from the viewpoint of productivity and workability, An off-line coat is preferred. Moreover, you may provide printing layers other than the printing layer of this invention as needed.

(Cylinder shrink label processing method)
An example of the shrink label processing method (cylindrical shrink label processing method) of the present invention is shown below. The shrink label of the present invention may be processed into a cylindrical label. For example, the shrink label is formed in a cylindrical shape so that the main orientation direction is the circumferential direction. Specifically, a shrink label having a predetermined width in the main orientation direction is formed into a cylindrical shape by overlapping both ends in the main orientation direction so that the outer surface (outside) of the shrink label is on the front side, and one side of the label Apply a solvent such as tetrahydrofuran (THF) or an adhesive (hereinafter referred to as an adhesive) to the inner surface of the belt at a width of about 2 to 4 mm, and apply the adhesive applied portion to the outer surface of the other side edge. To obtain a cylindrical shrink label. In addition, it is preferable that the printing layer is not provided in the part which apply | coats said adhesive agent etc., and the part to adhere | attach.

In addition, when providing the perforation for label cutting to a cylindrical shrink label, the perforation of predetermined length and a pitch is formed in the direction orthogonal to the circumferential direction. The perforation can be applied by a conventional method (for example, a method of pressing a disk-shaped blade having a cut portion and a non-cut portion repeatedly formed around it, a method using a laser, or the like). The process stage for perforating can be appropriately selected after the printing process and before and after the cylindrical processing process.

The cylindrical shrink label can be attached to a container to form a labeled container. For example, after a cylindrical shrink label is externally fitted to a predetermined container, the label is thermally contracted by heat treatment, and a container with a label is manufactured by closely contacting the container. Examples of the heat treatment include treatment with steam at 80 to 100 ° C. (passing through a heating tunnel filled with steam and steam). In addition, in the above, it is preferable that the shrink label is attached to the container so that the printed layer is on the inner side.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
Table 1 shows the composition of the printing inks used in Examples and Comparative Examples (blending amount) and the evaluation results of the obtained shrink labels. The blending composition of the above printing ink was indicated by the blending amount (parts by weight) based on weight.

Example 1
(Printing ink)
As monomer components, 50 parts by weight of acryloylmorpholine (trade name “ACMO”: specific monomer) manufactured by Kojin Co., Ltd., N-acryloyloxyethylhexahydrophthalimide (manufactured by Toagosei Co., Ltd., trade name “Aronix M-140”) ": Specific monomer) 43 parts by weight was used.
As an active energy ray polymerization initiator, 5,4 parts by weight of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by Ciba Specialty Chemicals, trade name “DAROCUR TPO”) was used.
As a surfactant, 1 part by weight of an organically modified (epoxy modified) polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-40-2670”) was used.
As a lubricant, 1 weight of oxidized polyethylene wax (manufactured by Clariant Japan Co., Ltd., trade name “Ceridust 3715”) was used.
The above components (monomer component, active energy ray polymerization initiator, surfactant and lubricant) were mixed using a homodisper to prepare a printing ink (100 parts by weight).

(Shrink label)
Polyester (PET) -based shrink film (trade name “Space Clean S7042”, thickness: 45 μm, heat shrinkage rate in main orientation direction (width direction) (90 ° C., 10 seconds) : 60%) on one side using a table-top flexographic printing press (manufactured by RK Print Coat Instruments Ltd., trade name “RK Flexiproof 100”) and 80 L / cm anilox at a process speed of 50 m / min. Printing ink layer (application layer) thickness: 2.5 μm) was applied.
Subsequently, on the shrink film coated with the above printing ink, using an ultraviolet irradiation device (trade name “LIGHT HAMMER-10” manufactured by Fusion UV Systems Japan Co., Ltd .: H + bulb), a lamp output of 120 W / cm, Ultraviolet irradiation was performed twice (2 passes) at a process speed of 50 m / min, and the printing ink layer was cured to obtain a shrink label (printing layer thickness: 2.5 μm).

Examples 2 and 4-6
As shown in Table 1, printing inks were prepared in the same manner as in Example 1 except that the types and blending amounts of the specific monomers were changed. Moreover, the shrink label was produced like Example 1 using the said printing ink.

Example 3 and Comparative Example 2
As shown in Table 1, the type and blending amount of the specific monomer were changed, and a monofunctional monomer was further added to produce a printing ink in the same manner as in Example 1. Moreover, the shrink label was produced like Example 1 using the said printing ink.

Examples 7 and 8, Comparative Example 1
As shown in Table 1, the type and blending amount of the specific monomer were changed, and a polyfunctional acrylate was further added to produce a printing ink in the same manner as in Example 1. Moreover, the shrink label was produced like Example 1 using the said printing ink.

Example 9
As shown in Table 1, the types and blending amounts of specific monomers are changed, and cellulose acetate propionate (manufactured by Eastman Chemical, trade name “CAP-504-0.2”) is added as a cellulose resin. In the same manner as in Example 1, a printing ink was prepared. Moreover, the shrink label was produced like Example 1 using the said printing ink.

Example 10
As shown in Table 1, the type and blending amount of the specific monomer, the blending amount of the lubricant, etc. were changed, and as a coloring material (pigment), titanium oxide (trade name “JR-707” manufactured by Teika Co., Ltd.) was used. The printing ink was prepared in the same manner as in Example 1. Moreover, the shrink label was produced like Example 1 using the said printing ink.

Comparative Example 3
As shown in Table 1, a printing ink was produced in the same manner as in Example 1 without using a specific monomer as a monomer component. Moreover, the shrink label was produced like Example 1 using the said printing ink.

(Evaluation)
Thermal shrinkage (90 ° C., 10 seconds), surface tackiness (tack-free property), peel resistance (tape peel test), resistance to fringe (in the main orientation direction) of the shrink labels obtained in Examples and Comparative Examples The following method evaluated the followability (shrink followability) with respect to shrink processing (scratch test) and scratch resistance (scratch test). In addition, in an Example and a comparative example, the main orientation direction of a shrink label is a main orientation direction of the shrink film which is a base material.

(1) Surface tack (tack free)
In Examples and Comparative Examples, immediately after producing a shrink label (immediately after the curing treatment by ultraviolet irradiation), the surface of the printed layer of the shrink label was touched with a finger and judged according to the following criteria based on the presence or absence of tack.
No tack (tack free): Good tack free (○)
Slightly tacky: Usable level (△)
Strong tack: Tack free defect (×)

(2) Peel resistance (tape peel test)
The test was conducted in accordance with JIS K 5600-5-6, except that no cross cuts were made on the grid. An adhesive tape having a width of 18 mm (manufactured by Nichiban Co., Ltd., trade name “Cello Tape (registered trademark))” is pasted on the surface of the printed layer of the shrink label obtained in Examples and Comparative Examples. It was peeled off in the direction.
In the area of 5 mm (longitudinal direction; orthogonal direction to the main orientation direction) × 5 mm (width direction; main orientation direction) in the surface of the printed layer with the adhesive tape attached, the peeled area (ratio) of the printed layer was visually observed. And judged according to the following criteria.
There is no peeling of the printing layer (the peeling area of the printing layer is 0%): good peeling resistance (○)
The peeled area of the printed layer is greater than 0% and less than 30%: Usable level (△)
The peeled area of the printed layer is 30% or more: Poor peel resistance (×)

(3) Scratch resistance (scratch test)
Samples for measurement measuring 100 mm (longitudinal direction; orthogonal direction to the main orientation direction) × 100 mm (width direction; main orientation direction) were collected from the shrink labels obtained in the examples and comparative examples. Hold both ends of the sample for measurement with both hands, and even 10 times. Whether the printed layer was peeled off (remaining area (ratio) of the printed layer) was visually observed and evaluated according to the following criteria.
The remaining area of the printed layer is 90% or more: Good resistance to padding (○)
The remaining area of the printed layer is less than 90%: Poor resistance to padding (×)

(4) Scratch resistance (scratch test)
Samples for measurement measuring 100 mm (longitudinal direction; orthogonal direction to the main orientation direction) × 100 mm (width direction; main orientation direction) were collected from the shrink labels obtained in the examples and comparative examples. Place the sample for measurement on a smooth table, observe the surface after rubbing the surface on the side where the printed layer was provided 10 times in the back of the nail of the hand (20 mm in the longitudinal direction). Judged by criteria.
The printed layer is not peeled at all. : Good scratch resistance (○)
There is slight peeling on the printed layer. : Scratch resistance is slightly poor but usable level (△)
The printed layer is peeled off significantly. : Scratch resistance failure (×)

(5) Followability to shrink processing (shrink followability)
(Sample for measurement)
From the shrink labels obtained in Examples and Comparative Examples, a label piece having a size of 12 cm (longitudinal direction; a direction perpendicular to the main orientation direction) × 12 cm (width direction; the main orientation direction) was cut out. Both ends of the label piece in the main orientation direction (width direction) [100 mm intervals excluding portions chucked by the jig (each 10 mm at both ends)] were fixed to a jig that can be fixed at 70 mm intervals (thermal contraction) It is in a slack state before processing). The label pieces having both ends fixed to the jig were immersed in warm water at 90 ° C. for 20 seconds and heat-treated, and the label pieces were heat-shrinked so as to have a length of 70% compared to before the heat-shrinking treatment ( 30% thermal shrinkage in the main orientation direction (width direction). In this way, a measurement sample was obtained that was heat shrunk by 30% in the main orientation direction (width direction).
Moreover, the sample for a measurement which carried out the heat shrink of 40% in the main orientation direction (width direction) was obtained like the above except having changed into the jig | tool which can fix a jig | tool at a 60 mm space | interval.
Furthermore, a sample for measurement was obtained in the same manner as described above except that the jig was changed to a jig that could be fixed at an interval of 50 mm and thermally contracted by 50% in the main orientation direction (width direction).
(Measurement)
The above-prepared measurement sample with 30% heat shrinkage, 40% heat shrinkage measurement sample, and 50% heat shrinkage measurement sample were each visually observed for the presence or absence of whitening. Judgment was made based on the following criteria.
There is no whitening even in the measurement sample that is 50% heat-shrinked: Excellent shrink followability (◎)
There is no whitening in the measurement sample with 40% heat shrinkage, but there is whitening in the measurement sample with 50% heat shrinkage.
There is no whitening in the measurement sample with 30% heat shrinkage, but there is whitening in the measurement sample with 40% heat shrinkage: Usable shrink followability (△)
There is also whitening in the measurement sample that was heat-shrinked by 30%.
In Example 10, instead of “whether there was whitening”, “whether there were cracks, wrinkles, etc.” was observed and judged in the same manner as described above. The shrink label of Example 10 did not generate cracks, wrinkles, etc. even in the measurement sample subjected to 50% thermal shrinkage (◎).

(6) Thermal shrinkage in main orientation direction (90 ° C., 10 seconds)
A rectangular measurement sample having a length of 200 mm (mark interval 150 mm) and a width of 10 mm in the measurement direction (main alignment direction) was cut out from the shrink labels obtained in Examples and Comparative Examples.
The measurement sample is heat-treated for 10 seconds (under no load) in hot water at 90 ° C., the difference between the marked lines before and after the heat treatment is read, and the heat shrinkage rate is calculated by the following formula.
Thermal contraction rate (%) = (L ₀ −L ₁ ) / L ₀ × 100
L ₀ : Marking interval before heat treatment L ₁ : Marking interval after heat treatment In the examples and comparative examples, the main orientation direction is the width direction of the shrink label.
Further, the thermal contraction rate (90 ° C., 10 seconds) in the direction orthogonal to the main alignment direction can be measured in the same manner as described above by changing the measurement direction to the direction orthogonal to the main alignment direction.

As can be seen from the evaluation results, the shrink label (Example) of the present invention has both excellent followability of the printed layer for shrink processing and tack-free property of the surface of the printed layer, and furthermore, adhesion between the printed layer and the substrate. It was a shrink label having excellent properties, excellent peel resistance, resistance to scratching, and excellent scratch resistance.
On the other hand, in the case where the content of the polyfunctional monomer in the monomer component forming the acrylic polymer exceeds 20% by weight (Comparative Example 1), the followability to shrink processing was lowered. In addition, when the content of the specific monomer in the monomer component forming the acrylic polymer is less than 50% by weight (Comparative Examples 2 and 3), the printed layer was insufficiently cured and the printed layer surface was tacked. .
In addition, the thermal contraction rate (90 degreeC, 10 second) of the main orientation direction of the shrink label obtained by the Example and the comparative example was 60%.

Claims

Contains at least 80% by weight of a monofunctional monomer on at least one side of the substrate, and includes acryloylmorpholine, N-acryloyloxyethylhexahydrophthalimide, paracumylphenol EO-modified acrylate, and 2-hydroxy-3-phenoxypropyl acrylate A shrink label comprising a printed layer containing an acrylic polymer formed from a monomer component containing 50% by weight or more of a monomer selected from the group consisting of:
The shrink label according to claim 1, wherein the monomer component contains 5 to 90% by weight of acryloylmorpholine.
The shrink label according to claim 1 or 2, wherein the monomer component contains 5 to 90% by weight of N-acryloyloxyethyl hexahydrophthalimide.
The shrink label according to any one of claims 1 to 3, wherein the printed layer is a printed layer formed by active energy ray curing.