JP2023022442A - Label and bottle container - Google Patents

Abstract

To provide a label and a bottle container causing few water droplets.SOLUTION: A label has a base material layer, a middle layer and a coating layer in this order. The base material layer and the middle layer are thermoplastic resin films. Smoothness of a surface of the coating layer is 5,000 seconds or more, and an angle of contact to surface water of the coating layer ranges from 85 to 104 degrees.SELECTED DRAWING: Figure 1

Description

The present invention relates to labels and bottle containers.

A bottle container such as a PET bottle is sometimes attached with a label on which the product name, description, and the like are printed. As a label, a resin film having excellent water resistance is generally used (see Patent Documents 1 and 2, for example). Such resin-made labels include a body-wrapped label that is wound around the body of the bottle container and whose ends are adhered with an adhesive, and a shrink label that adheres tightly to the outer peripheral surface of the bottle container by heat shrinkage. be.

JP 2013-122514 A JP-A-2002-219751 JP-A-1-99935

Bottle containers containing beverages and the like are often stored at low temperatures such as refrigerators. Since resin labels are thin and easily transfer heat from the outside air, dew condensation is likely to occur when the bottle container is moved from a low temperature to room temperature. Water droplets caused by dew condensation fall, and post-treatment of the puddle formed under the bottle container is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a label and a bottle container from which water drops are less likely to fall.

As a result of intensive studies by the present inventors to solve the above problems, it was found that the above problems can be solved by adjusting the surface smoothness of the outermost layer and the contact angle with water when attached to a bottle container. and completed the present invention.
That is, the present invention is as follows.

[1] A label having a substrate layer, an intermediate layer and a coating layer in this order,
The base layer and the intermediate layer are thermoplastic resin films,
The smoothness of the surface of the coating layer is 5000 seconds or more,
A label, wherein the surface of the coating layer has a contact angle with water of 85 to 104 degrees.

[2] The label according to [1] above, wherein the dynamic friction coefficient of the coating layer is 0.3 to 0.5.

[3] The label according to [1] or [2] above, wherein the adhesive strength of the coating layer is 2 to 10 N/50 mm.

[4] The label according to any one of [1] to [3] above, wherein the filler content in the intermediate layer is 5% by mass or less.

[5] The coating layer contains an ethyleneimine polymer and a (meth)acrylic acid ester copolymer.
The label according to any one of [1] to [4] above.

[6] The label according to [5] above, wherein the content of the ethyleneimine polymer in the coating layer is 30 to 70% by mass.

[7] The label according to [5] or [6] above, wherein the content of the (meth)acrylate copolymer in the coating layer is 30 to 70% by mass.

[8] The label according to any one of [1] to [7] above, wherein the substrate layer is a porous stretched film containing an olefin resin and a filler.

[9] A bottle container, wherein the label according to any one of [1] to [8] above is attached to the surface of the bottle body.

ADVANTAGE OF THE INVENTION According to this invention, the label and bottle container with few drops of water droplets can be provided.

FIG. 4 is a cross-sectional view showing an example of a label; 1 is a perspective view showing an example of a labeled bottle; FIG. FIG. 4 is an enlarged view of the surface of the bottle body near the label; It is a figure explaining the evaluation method of the fall prevention property of a water droplet.

Hereinafter, the label and bottle container of the present invention will be described in detail. The following are examples (representative examples) of the present invention, and the present invention is not limited thereto.
In the following description, the description of "(meth)acrylic" indicates both acrylic and methacrylic.

[label]
The label of the present invention is a laminated film having a substrate layer, an intermediate layer and a coating layer in this order. The base layer and the intermediate layer are thermoplastic resin films. The surface of the coating layer has a smoothness of 5000 seconds or more and a contact angle with water of 85 to 104 degrees.

When the label of the present invention is attached to the outer surface of the bottle container, the substrate layer is located on the side closer to the bottle container, and the coating layer is located on the outermost surface on the side opposite to the bottle container. When dew condensation occurs due to the temperature difference between the bottle container and the outside air temperature, water droplets form on the surface of the label on the coating layer side. The contact angle of the surface of the coating layer with water tends to increase as the surface smoothness increases.

In the present invention, the contact angle of the surface of the coating layer with water is adjusted to the above specific range by adjusting the smoothness of the coating layer to a relatively high range. If the smoothness of the outermost surface is equal to or higher than the above specific value and the contact angle with water is within the above specific range, dew condensation is less likely to spread and water droplets are less likely to connect with each other. to prevent water droplets from falling. Although the specific mechanism has not been clarified, if the contact angle with water is within the above-mentioned specific range, the interfacial tension acting on each interface between the coating layer surface, water droplets, and the air under gravity will be easily balanced. It is speculated that one of the reasons why water droplets can be prevented from falling is that the movement of water droplets in the gravitational direction can be suppressed. Therefore, it is possible to provide a label on which water droplets are less likely to drop even if dew condensation occurs.

FIG. 1 shows an example of the label of the present invention.
A label 10 illustrated in FIG. 1 includes a substrate layer 11 and an intermediate layer 12 and a coating layer 13 on one surface of the substrate layer 11 . The printed layer 14 can be formed by printing on the coating layer 13 .
Each layer will be described below.

(Coating layer)
As described above, the coating layer is provided on the outermost surface of the label of the present invention to prevent water droplets from falling. In addition, when a printed layer is formed, the coating layer can enhance the adhesion to the ink and improve the printability of the label.

The coating layer may contain an ethyleneimine-based polymer and a (meth)acrylic acid ester copolymer from the viewpoint of adjusting the contact angle of the surface of the coating layer with water within a specific range. These components enhance the water repellency and increase the contact angle of the coating layer surface with water. In addition, the ethyleneimine-based polymer can enhance the adhesion to the print layer formed on the coating layer. The (meth)acrylic acid ester copolymer suppresses adhesion of foreign matter to the label due to charging.

<Ethyleneimine-based polymer>
Examples of ethyleneimine-based polymers include polyethyleneimine, poly(ethyleneimine-urea), ethyleneimine adducts of polyamine polyamides, alkyl modified products thereof, cycloalkyl modified products, aryl modified products, allyl modified products, aralkyl modified products, Benzyl-modified, cyclopentyl-modified, cycloaliphatic-hydrocarbon-modified, glycidol-modified, or hydroxides thereof can be mentioned. Modifiers for obtaining modified compounds include, for example, methyl chloride, methyl bromide, n-butyl chloride, lauryl chloride, stearyl iodide, oleyl chloride, cyclohexyl chloride, benzyl chloride, allyl chloride, and cyclopentyl chloride. .

〔上記式（Ｉ）中、Ｒ^１とＲ^２はそれぞれ独立して水素原子；炭素数１～１２の直鎖又は分岐状のアルキル基；炭素数６～１２の脂環式構造を有するアルキル基又はアリール基を表す。Ｒ^３は水素原子；ヒドロキシ基を含んでいてもよい炭素数１～１８の範囲のアルキル基又はアリル基；ヒドロキシ基を含んでいてもよい炭素数６～１２の脂環式構造を有するアルキル基又はアリール基を表す。ｍは２～６の整数を表し、ｎは２０～３０００の整数を表す。〕 Among them, an ethyleneimine-based polymer represented by the following general formula (I) is preferable from the viewpoint of improving the transferability and adhesiveness of ink or toner used for printing, particularly ultraviolet curable ink.

[In the above formula (I), R ¹ and R ² are each independently a hydrogen atom; a linear or branched alkyl group having 1 to 12 carbon atoms; an alkyl group having an alicyclic structure having 6 to 12 carbon atoms; or represents an aryl group. R ³ is a hydrogen atom; an alkyl group or allyl group having 1 to 18 carbon atoms and optionally containing a hydroxy group; an alkyl group having an alicyclic structure having 6 to 12 carbon atoms and optionally containing a hydroxy group. or represents an aryl group. m represents an integer of 2-6, and n represents an integer of 20-3000. ]

The content of the ethyleneimine polymer ester copolymer in the coating layer is preferably 30% by mass or more, more preferably 40% by mass or more, from the viewpoint of increasing the contact angle with water on the surface of the coating layer. From the viewpoint of adjusting the contact angle with water so as not to excessively increase, the content of the ethyleneimine polymer ester copolymer is preferably 70% by mass or less, more preferably 50% by mass or less. % by mass or less is more preferable.

<(Meth) acrylic acid ester copolymer>
Monomers constituting the (meth)acrylic acid ester copolymer include (meth)acrylic acid ester monomers, derivatives thereof, and vinyl compounds copolymerizable therewith. (Meth)acrylic acid ester monomers include (meth)acrylic acid aliphatic alkyl esters, alicyclic hydrocarbon groups or aromatic hydrocarbons having a linear or branched alkyl group having 1 to 20 carbon atoms in the alkyl group. (Meth)acrylic acid esters having a cyclic skeleton such as a group, or derivatives thereof. Derivatives include (meth)acrylic acid esters obtained by introducing a functional group such as a hydroxy group or an amino group into the above alkyl group, alicyclic hydrocarbon group or aromatic hydrocarbon group.

Examples of the (meth)acrylic acid aliphatic alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, ( meth)hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate , tetradecyl (meth)acrylate, or octadecyl (meth)acrylate.

Examples of (meth)acrylic acid esters having a cyclic skeleton include (meth)acrylic acid alicyclic alkyl esters having an alicyclic hydrocarbon group such as cyclohexyl (meth)acrylate or isobornyl (meth)acrylate; ) acrylate, phenoxyethyl (meth)acrylate or benzyl (meth)acrylate having an aromatic hydrocarbon group (meth)acrylic acid aryl ester.

Examples of the (meth)acrylic acid esters introduced with a hydroxy group, that is, the (meth)acrylic acid esters having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or 2-hydroxy Butyl (meth)acrylate and the like can be mentioned.

Examples of the (meth)acrylic acid ester into which an amino group is introduced, that is, the (meth)acrylic acid ester having an amino group include monoethylamino (meth)acrylate, diethylamino (meth)acrylate, or dimethylaminoethyl (meth)acrylate. etc. These (meth)acrylic acid esters having an amino group may be (meth)acrylic acid esters having an ammonium base obtained by quaternizing the amino group with an acid or an alkylating agent.
These may be used individually by 1 type, and may use 2 or more types together.

Further, as the (meth)acrylic acid ester copolymer, a cationic type, anionic type, amphoteric type, or nonionic type (meth)acrylic acid ester copolymer having a functional group introduced as necessary can be used. can.

Among these, cationic or amphoteric (meth)acrylic acid ester copolymers are preferred, and nitrogen-containing (meth)acrylic acid ester copolymers are more preferred. Examples thereof include, for example, primary to quaternary nitrogen-containing (meth)acrylic acid ester copolymers.

The method for producing the (meth)acrylate copolymer is not particularly limited. As a method for synthesizing , various commonly used polymerization methods can be applied. For example, a cationic (meth)acrylic acid ester copolymer having an ammonium salt structure may use an ammonium salt as a monomer constituting the copolymer.

The (meth)acrylic acid ester copolymer is generally dissolved in a solvent such as water, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, toluene and xylene and used in a solution state. Among them, it is preferable to use it in the form of an aqueous solution. The concentration of the (meth)acrylic acid ester copolymer aqueous solution is preferably 0.5 to 40%, more preferably 1 to 20%, from the viewpoint of handleability during application.

The content of the (meth)acrylic acid ester copolymer in the coating layer is preferably 30% by mass or more, more preferably 50% by mass or more, from the viewpoint of increasing the contact angle with water on the surface of the coating layer. 52% by mass or more is more preferable. From the viewpoint of adjusting the contact angle with water so as not to excessively increase, the content of the ethyleneimine polymer-ester copolymer is preferably 70% by mass or less, more preferably 60% by mass or less.

<Other additives>
The coating layer contains antioxidants such as sterically hindered phenol, phosphorus, amine, and sulfur; light stabilizers such as sterically hindered amine, benzotriazole, and benzophenone, as long as they do not impair the effects of the present invention. it may contain additives such as dispersants or antistatic agents. The content of each additive in the coating layer is usually 0.001 to 1% by mass.

(Base material layer)
The base layer can impart mechanical strength to the label. As a result, sufficient stiffness can be obtained when printing on the label, and excellent handleability can be obtained.

<Thermoplastic resin>
The base layer is a thermoplastic resin film. Examples of thermoplastic resins that can be used for the substrate layer include olefin resins, ester resins, amide resins, polyvinyl chloride resins, polystyrene resins, and polycarbonate resins. From the viewpoint of mechanical strength, the base material layer preferably contains an olefin resin or an ester resin as a thermoplastic resin, and more preferably contains an olefin resin.

Examples of olefin-based resins include propylene-based resins and ethylene-based resins. Propylene-based resins are preferred from the viewpoint of moldability and mechanical strength.

The propylene-based resin is not particularly limited as long as propylene is used as the main monomer. Examples include isotactic and syndiotactic polymers obtained by homopolymerizing propylene. It is also a copolymer of propylene, which is the main component, and α-olefins such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene. , propylene-α-olefin copolymers and the like can also be used. The copolymer may be a binary system or a multi-component system having three or more monomer components, and may be a random copolymer or a block copolymer. Also, a propylene homopolymer and a propylene copolymer may be used in combination. Among these, a propylene homopolymer is preferable as a main raw material for the base material layer because it is easy to handle.

Examples of ethylene-based resins include high density polyethylene with a density of 0.940 to 0.965 g/cm ³ , medium density polyethylene with a density of 0.920 to 0.934 g/cm ³ , and density of 0.900 to 0.920 g. / cm ³ linear low-density polyethylene, ethylene, etc. as the main component, propylene, butene, hexene, heptene, octene, 4-methylpentene-1, etc. α-olefin copolymer, ethylene-acrylic acid copolymers, ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylate copolymers, metal salts of ethylene-methacrylic acid copolymers (metals are zinc, aluminum, lithium, sodium, potassium, etc.), Examples include ethylene-cyclic olefin copolymers.

Examples of ester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
Examples of amide-based resins include nylon-6, nylon-6,6, nylon-6,10, and nylon-6,12.

The content of the thermoplastic resin in the substrate layer is preferably 50% by mass or more, more preferably 70% by mass or more. If the content is 50% by mass or more, the mechanical strength of the base material layer is likely to be improved. On the other hand, there is no particular upper limit for the content of the thermoplastic resin, and it may be 100% by mass, or less than 100% by mass with the addition of fillers, additives, etc. described later within a range that does not affect the strength or moldability. may be

<Filler>
The base material layer can contain a filler. The inclusion of a filler facilitates the formation of voids inside, and can increase the degree of whiteness or opacity. Examples of fillers that can be used in the base material layer include inorganic fillers and organic fillers.

Among them, the substrate layer is preferably a porous stretched film containing an olefinic resin and a filler. The stretching forms a large number of pores with the filler as the nucleus inside the film, and these pores enhance the heat insulating properties of the substrate layer. Since heat transfer from the outside air can be suppressed, it becomes easier to suppress the occurrence of dew condensation due to the temperature difference between the bottle container and the outside air.

Examples of inorganic fillers include heavy calcium carbonate, light calcium carbonate, calcined clay, silica, diatomaceous earth, clay, talc, titanium oxide such as rutile-type titanium dioxide, barium sulfate, aluminum sulfate, zinc oxide, magnesium oxide, mica, and celery. Inorganic particles such as site, bentonite, sepiolite, vermiculite, dolomite, wollastonite, and glass fibers. Among them, heavy calcium carbonate, clay or diatomaceous earth is preferable because it has good pore moldability and is inexpensive. For the purpose of improving dispersibility, etc., the surface of the inorganic filler may be surface-treated with a surface-treating agent such as fatty acid.

Examples of organic fillers include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyamide, polycarbonate, polystyrene, cyclic olefin homopolymer, ethylene-cyclic olefin copolymer, polyethylene sulfide, polyimide, poly Organic particles such as methacrylate, polyetheretherketone, polyphenylene sulfide, or melamine resin are included.
One of the above inorganic fillers or organic fillers can be used alone, or two or more thereof can be used in combination.

From the viewpoint of increasing the whiteness or opacity of the substrate layer, the content of the filler in the substrate layer is preferably 10% by mass or more, more preferably 15% by mass or more. In addition, from the viewpoint of improving the uniformity of molding of the base material layer, the content of the filler in the base material layer is preferably 70% by mass or less, more preferably 60% by mass or less, and 50% by mass or less. More preferred. On the other hand, from the viewpoint of increasing the transparency of the substrate layer, the content of the filler in the substrate layer may be less than 10% by mass, or may be 0% by mass.

The average particle size of the inorganic filler or organic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more, from the viewpoint of ease of forming pores. From the viewpoint of imparting mechanical strength such as tear resistance, the average particle size of the inorganic filler or organic filler is preferably 15 μm or less, more preferably 5 μm or less, and even more preferably 2 μm or less.

The average particle diameter of the inorganic filler is the volume average particle diameter corresponding to 50% of the cumulative volume (cumulative 50% particle diameter) measured by a particle measuring device such as a laser diffraction particle size distribution measuring device (Microtrac, manufactured by Nikkiso Co., Ltd.). D50. Also, the average particle size of the organic filler is the average dispersed particle size when dispersed in the thermoplastic resin by melt-kneading and dispersion. The average dispersed particle size can be obtained by observing the cut surface of the thermoplastic resin film containing the organic filler with an electron microscope, measuring the maximum size of at least 10 particles, and calculating the average value.

<Porosity>
When the substrate layer has pores inside, the porosity, which indicates the ratio of pores in the layer, is preferably 10% or more, more preferably 20% or more, from the viewpoint of obtaining opacity. Preferably, it is more preferably 30% or more. From the viewpoint of maintaining mechanical strength, the porosity is preferably 70% or less, more preferably 55% or less, and even more preferably 40% or less. On the other hand, from the viewpoint of increasing the transparency of the substrate layer, the porosity may be less than 10% or may be 0%.
The porosity can be obtained from the ratio of the area occupied by pores in a certain region of the cross section of the sample observed with an electron microscope.

In general, the higher the filler content, the higher the porosity, and the higher the whiteness or opacity of the substrate layer. The filler content or porosity can be selected according to the transparency, whiteness, etc. required for the label.

<Other additives>
The substrate layer, if necessary, antioxidants such as sterically hindered phenols, phosphorus, amines, and sulfur; light stabilizers such as sterically hindered amines, benzotriazoles, and benzophenones; dispersants, or Ingredients such as antistatic agents can be included. When the substrate layer contains these components, the content of each component is preferably 0.001 to 1% by mass relative to the total mass of each component constituting the substrate layer.

(middle layer)
The intermediate layer is located below the coating layer. The intermediate layer smoothes the irregularities on the surface of the substrate layer, thereby increasing the smoothness of the coating layer.

The intermediate layer in the present invention is a thermoplastic resin film. As the thermoplastic resin used for the intermediate layer, the same resins listed in the <Thermoplastic resin> section of the substrate layer can be used, and the preferred resins are also the same.

From the viewpoint of increasing the smoothness of the coating layer, the intermediate layer preferably does not contain a filler. Even when the intermediate layer contains a filler, the content of the filler in the intermediate layer is preferably 5% by mass or less from the viewpoint of adjusting the smoothness of the coating layer within the above specific range.

<Print layer>
The printed layer is provided by printing characters, drawings, etc. on the surface of the substrate layer opposite to the heat seal layer. The printed layer is a layer composed of an ink component transferred by printing.

(Physical properties of label)
<Thickness>
The thickness of all layers of the label of the present invention is preferably 50 µm or more, more preferably 60 µm or more, preferably 300 µm or less, and more preferably 150 µm or less.

The ratio of the thickness of the substrate layer to the total thickness of the label of the present invention is preferably 50 to 90%. When the thickness ratio is 50% or more, sufficient stiffness of the label is likely to be obtained, and workability when attaching to the bottle container is likely to be improved. Further, when the thickness ratio is 90% or less, when the base layer having a higher porosity than the other layers is torn, the tear is less likely to propagate to other layers, and the strength of the label is likely to be improved.

Specifically, the thickness of the substrate layer is preferably 30 μm or more, more preferably 40 μm or more. When the thickness is 30 µm or more, the label tends to have sufficient stiffness, and the workability when attaching it to a bottle container tends to improve. Moreover, the thickness of the substrate layer is preferably 120 μm or less, more preferably 90 μm or less. When the thickness is 120 μm or less, when the base layer having a higher porosity than the other layers is torn, the tear is less likely to propagate to the other layers, and the strength of the label is likely to be improved. .

The thickness of the intermediate layer is preferably 5 μm or more, more preferably 8 μm or more. When the thickness is 5 μm or more, it is easy to fill in the unevenness of the substrate layer and improve the smoothness of the surface of the coating layer. Also, the thickness of the intermediate layer is preferably 50 μm or less, more preferably 20 μm or less. When the thickness is 50 µm or less, the weight of the label can be easily reduced.

The thickness of the coating layer is preferably 0.001 μm or more, more preferably 0.01 μm or more. When the thickness is 0.001 μm or more, it is easy to adjust the contact angle of the coating layer surface with water within a specific range. Moreover, the thickness of the coating layer is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less. When the thickness is 5 µm or less, it is easy to suppress stickiness on the surface of the coating layer.

<Smoothness>
In the present invention, the surface smoothness of the coating layer is 5000 seconds or more and usually 99999 seconds or less. If the smoothness is within this range, it becomes easier to adjust the contact angle of the surface of the coating layer with water to 85 to 104 degrees. The contact angle is influenced in a complex manner by surface components, smoothness, intervals between surface irregularities, etc., and the higher the smoothness, the larger the contact angle with water. Therefore, from the viewpoint of adjusting the contact angle to 85° or more, the smoothness is preferably 10000 seconds or more, more preferably 20000 seconds or more. On the other hand, from the viewpoint of adjusting the contact angle to 104° or less, the smoothness is preferably 50000 seconds or less, more preferably 40000 seconds or less.

The above smoothness is Oken smoothness measured according to JIS P 8155:2010 "Paper and paperboard-Smoothness test method-Oken method". For the measurement, a digital Oken type air permeability and smoothness tester (“EYO-55-1M” manufactured by Asahi Seiko Co., Ltd.) can be used.
The smoothness can be adjusted within the above specific range by, for example, providing an intermediate layer between the coating layer and the substrate layer, or forming the coating layer by applying a coating liquid.

<Contact angle with water>
In the present invention, the contact angle of water on the surface of the coating layer is 85 to 104 degrees. If the contact angle with water is within this range, it is difficult for the water droplets generated by condensation to spread, and the water droplets are less likely to connect with each other. In addition, it is presumed that the interfacial tension acting on each interface between the coating layer surface, the water droplets, and the air under gravity is easily balanced, and the movement of the water droplets in the direction of gravity, that is, the falling of the water droplets, can be suppressed. If the contact angle with water is too large or too small, the balance of the interfacial tension tends to be lost, so from the viewpoint of maintaining the balance, the contact angle is preferably 90° or more, more preferably 94° or more. While preferred, 100° or less is preferred.

The contact angle with water was measured using a fully automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., equipment name: DM-700) in an environment of 23 ° C. and a relative humidity of 50%. is the contact angle measured when 1 μL of water is dropped on the
The contact angle with water can be adjusted within the above specific range by adjusting the smoothness of the coating layer, the water repellency of the coating layer, and the like.

FIG. 2A shows an example of a labeled bottle container.
In FIG. 2A, a bottle container 20 has a label 10 wound around the body of a container body 21 to which a cap 22 can be attached. An adhesive layer 40 is provided on one end of the label 10, and the other end of the label 10 is superimposed on the adhesive layer 40, and the ends of the label 10 are adhered to each other with an adhesive.

2B is an enlarged view within the frame 20e of FIG. 2A, showing the surface of the bottle container 21 and the label 10. FIG.
When dew condensation occurs in the labeled bottle 20, water droplets 30 are formed on the coating layer of the label 10. However, since the surface of the coating layer has a contact angle with water within the above range, the water droplets 30 are less likely to fall. It's becoming

<Coefficient of dynamic friction>
The coefficient of dynamic friction of the label is preferably 0.3 or more and 0.5 or less from the viewpoint of obtaining good rubber roll transportability.
A dynamic friction coefficient means the value measured based on JISK7125:1999.

<Adhesive strength>
The adhesive strength of the label of the present invention is preferably 2 to 10 N/50 mm.

(Label manufacturing method)
The method for manufacturing the label of the present invention is not particularly limited. For example, the label of the present invention can be manufactured by forming and laminating each layer of film.

<Film molding>
Film forming methods for each layer include extrusion molding (cast molding) with a T-die, inflation molding with an O-die, and calender molding with a rolling roll.

Methods for laminating each film include a coextrusion method, an extrusion lamination method, a coating method, a film lamination method, and the like, and these can be combined.
In the co-extrusion method, each layer of resin composition is supplied to a multilayer die, laminated within the multilayer die, and extruded. According to the co-extrusion method, lamination is performed in parallel with film formation.
In the extrusion lamination method, one of the films is formed first, and the molten resin composition is extruded and laminated on this film in the form of a film, which is then nipped with rolls while being cooled. According to the extrusion lamination method, film formation and lamination are performed in separate steps.
In the coating method, a solution, emulsion or dispersion of a resin composition is coated on one film and dried to form and laminate another film.
In the film bonding method, each layer of film is formed and the two are bonded together via an adhesive. According to the film lamination method, film formation and lamination are performed in separate steps.

<Stretching>
Each layer may be a non-stretched film or a stretched film. Also, each layer may be stretched individually before lamination, or may be stretched together after lamination. After the unstretched layer and the stretched layer are laminated, they may be stretched again.

Stretching methods include, for example, a longitudinal stretching method using a difference in circumferential speed between rolls, a transverse stretching method using a tenter oven, a sequential biaxial stretching method combining these methods, a rolling method, and a simultaneous two-stretching method using a combination of a tenter oven and a pantograph. An axial stretching method and a simultaneous biaxial stretching method using a combination of a tenter oven and a linear motor can be used. A simultaneous biaxial stretching (inflation molding) method can also be used, in which a circular die connected to a screw extruder is used to extrude a molten resin into a tubular shape, and then air is blown into the tubular shape.

When the thermoplastic resin used for each layer is an amorphous resin, the stretching temperature when stretching is preferably in the range of the glass transition point of the thermoplastic resin or higher. Also, when the thermoplastic resin is a crystalline resin, the stretching temperature should be above the glass transition point of the non-crystalline portion of the thermoplastic resin and below the melting point of the crystalline portion of the thermoplastic resin. is preferred, and specifically, a temperature lower than the melting point of the thermoplastic resin by 2 to 60°C is preferred.

The stretching speed is not particularly limited, but from the viewpoint of stable stretching molding, it is preferably in the range of 20 to 350 m/min.
In addition, the draw ratio can also be appropriately determined in consideration of the properties of the thermoplastic resin to be used. For example, when a thermoplastic resin film containing a propylene homopolymer or a copolymer thereof is stretched in one direction, the draw ratio is usually about 1.2 times or more, preferably about 2 times or more. , is usually 12 times or less, preferably 10 times or less. In the case of biaxial stretching, the draw ratio in area draw ratio is usually 1.5 times or more, preferably 10 times or more, while it is usually 60 times or less, preferably 50 times or less. .
If the draw ratio is within the above range, the desired porosity can be obtained and the opacity tends to be improved. In addition, the film tends to be less likely to break and can be stretched stably.

<Surface treatment>
It is preferable that each layer is subjected to surface treatment to activate the surface in order to enhance adhesion to adjacent layers.
Surface treatments include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, ozone treatment, and the like, and these treatments can be combined. Among them, corona discharge treatment or flame treatment is preferable, and corona discharge treatment is more preferable.

The amount of discharge when performing corona discharge treatment is preferably 600 J/m ² (10 W·min/m ² ) or more, more preferably 1,200 J/m ² (20 W·min/m ² ) or more. . Also, the discharge amount is preferably 12,000 J/m ² (200 W·min/m ² ) or less, more preferably 10,800 J/m ² (180 W·min/m ² ) or less. The amount of discharge when flame treatment is performed is preferably 8,000 J/m ² or more, more preferably 20,000 J/m ² or more, and the discharge amount is preferably 200,000 J/m ² . or less, more preferably 100,000 J/m ² or less.

<Formation of printed layer>
The printed layer can be formed by printing on the coating layer. The printed information includes, for example, a product name, a product display such as a logo, a manufacturer, a sales company name, a method of use, a bar code, and the like.
The printing method is not particularly limited, and examples thereof include gravure printing, offset printing, flexographic printing, seal printing, and screen printing.

<Label processing>
The label of the present invention can be processed into a required shape and size by cutting or punching the laminated film obtained by the above steps. Although cutting or punching can be performed before printing, it is preferable to perform cutting or punching after printing in terms of ease of work.

[bottle container]
The bottle container of the present invention has the label of the present invention attached to the surface of the bottle body.

(How to attach the label)
As a method for attaching the label of the present invention to the bottle container, for example, a band-shaped label is wound around the outer peripheral surface of the bottle container, and the ends of the label are overlapped and adhered with an adhesive. There are a shrink method in which the label is heat-shrunk to adhere to the outer surface of the bottle container after covering the periphery of the bottle container, and a stretch method in which a cylindrical label is stretched and attached to the outer periphery of the bottle body.

Among them, the glue method is preferable because it does not require a large manufacturing facility and the processing speed can be increased only by coating the adhesive and bonding, and the production cost can be reduced. In the case of the glue method, labels can be attached to bottle containers made of various materials by selecting the type of adhesive, or by appropriately selecting the phase transition temperature in the case of an emulsion-based adhesive. .

(bottle container)
Materials for the bottle container to which the label of the present invention can be attached include metals such as aluminum and stainless steel; glass; ceramics; polyethylene terephthalate (PET), high-density polyethylene, polypropylene, polyester, polystyrene, polyvinyl chloride, polycarbonate, and the like and plastics. Among them, metal, glass, ceramics, high-density polyethylene, polypropylene, polyester, or polystyrene are suitable from the viewpoint of adhesion when wound, and polyester such as PET bottles is particularly suitable.

The shape of the bottle container to which the label of the present invention is attached is not particularly limited. For example, the cross-section of the portion of the bottle container to which the label is attached may be circular, elliptical, rectangular, or any other shape. From the viewpoint of ease of winding, the cross-sectional shape of the portion to be wound is preferably circular or elliptical, more preferably circular. Moreover, the bottle container to which the label of the present invention is attached may be a cylindrical bottle container having a hollow portion, or may be a bottle container having no hollow portion. The diameter of the portion of the bottle container around which the label is wound may be smaller than or the same as the diameter of the portion adjacent to that portion. When the diameter of the portion of the bottle container around which the label is wound is smaller than that of the adjacent portion, that is, when the label is wound in the concave portion provided on the outer peripheral surface of the bottle container, peeling of the label due to rubbing or the like is suppressed. easy and desirable.

Applications of the bottle container to which the label of the present invention is attached are also not particularly limited, and examples thereof include containers, piping, advertising bottle containers, batons, poles, and lighting fixtures. Among them, containers are suitable as bottle containers to which labels are attached, and among these containers, beverage containers are suitable. Beverage containers include, for example, water (mineral water), soft drinks, carbonated drinks, juices, milk drinks, lactic acid drinks, beer, wine, Japanese sake, various distilled spirits, nutritional drinks, seasonings, medical drugs, cosmetics, Examples include containers for chemicals and the like.

(Label coverage)
The higher the coverage of the label on the bottle container, the easier it is to reduce dripping. Therefore, from the viewpoint of suppressing the dropping of water droplets, the coverage is preferably 50% or more, preferably 60% or more, and may be 100%. From the viewpoint of workability in winding the label, the coverage is usually 90% or less.

The label coverage (%) is obtained as a ratio of the area of the label to the area of the side surface of the bottle container to which the label is attached. For example, when the body of the bottle container is cylindrical, the side surface area of the cylindrical body is obtained from the diameter of the body of the bottle container and the height from the bottom of the bottle container to the bottom of the cap. The ratio of the area of the label to the area is obtained as the coverage. If the diameter of the body differs depending on the height, the body is regarded as a cylindrical body with the diameter equal to the maximum diameter of the body, and the area of the side surface is obtained. In addition, when the body of the bottle container is a prismatic body, the side surface area is obtained from the length of each side of the body of the bottle container and the height from the bottom of the bottle container to the bottom of the cap. The coverage rate is calculated as the ratio of the area of the label to the area of the side surface. If the length of the side of the body differs depending on the height, the area of the side is determined by regarding the body as a prismatic body having the longest side on each side of the body.

Assuming that the bottle container is a cylindrical body, the diameter of the cylindrical body is d1, and the height of the body (the height from the bottom of the body to the bottom of the cap) is d2, the side surface area of the bottle container is It can be expressed as π×d1×d2. The ratio of the area of the label covering the side surface to the area of the side surface is the coverage rate (%) of the label.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. The following materials, usage amounts, ratios, processing details, processing procedures, etc. can be changed as appropriate without departing from the scope of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the specific examples shown below.

[Preparation of coating liquid]
(Aqueous solution of ethyleneimine polymer)
100 mass of a 25 mass% aqueous solution of polyethyleneimine (trade name: Epomin P-1000, manufactured by Nippon Shokubai Co., Ltd., degree of polymerization: 1600) was placed in a four-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen gas inlet. 10 parts by mass of n-butyl chloride and 10 parts by mass of propylene glycol monomethyl ether were added. This was stirred under a nitrogen stream and subjected to a modification reaction at a temperature of 80° C. for 20 hours to obtain a 20 mass % butyl-modified polyethyleneimine aqueous solution (d).

(Aqueous solution of (meth)acrylic acid ester copolymer)
35 parts by mass of dimethylaminoethyl methacrylate, 20 parts by mass of ethyl methacrylate, 20 parts by mass of cyclohexyl methacrylate, 25 parts by mass of stearyl methacrylate, 150 parts by weight of ethyl alcohol and 1 part by weight of azobisisobutyronitrile were added. After purging the inside of the system with nitrogen, a polymerization reaction was carried out at a temperature of 80° C. for 6 hours under a nitrogen stream. Then, 70 parts by mass of a 60% by mass ethyl alcohol solution of 3-chloro-2-hydroxypropylammonium chloride was added, and the mixture was further reacted at a temperature of 80° C. for 15 hours. Thereafter, ethyl alcohol was distilled off while water was added dropwise to obtain a quaternary ammonium salt-containing acrylic resin aqueous solution (e) having a solid content of 30% by mass.

(Emulsion)
Using a twin-screw extruder (TEX30HSS, manufactured by Japan Steel Works, Ltd.), melt-kneading and emulsification of the starting resin were performed according to the following procedures to produce emulsion (f).
Specifically, pellet-shaped ethylene/methacrylic acid/acrylic acid ester copolymer resin (trade name: Nucrel N035C, manufactured by Mitsui DuPont Polychemicals, 2.0 kg) was supplied from a hopper to the extruder, and the screw was rotated. Melting and kneading were carried out under conditions of several 270 rpm and a cylinder temperature of 160°C to 250°C.

A dispersant was then prepared as follows. A reactor having an inner volume of 150 L equipped with a condenser, a nitrogen inlet tube, a stirrer, a monomer dropping funnel and a jacket for heating was charged with 40 kg of isopropanol. While stirring this, 12.6 kg of N,N-dimethylaminoethyl methacrylate (trade name: Methacrylate DMA, manufactured by Sanyo Chemical Industries, Ltd.), 12.6 kg of butyl methacrylate (trade name: Acryester B, manufactured by Mitsubishi Rayon Co., Ltd.), and 2.8 kg of higher alcohol methacrylate (trade name: Acryester SL, manufactured by Mitsubishi Rayon Co., Ltd.). After purging with nitrogen, the internal temperature was raised to 80° C., and 0.3 kg of azobisisobutyronitrile was added as a polymerization initiator to initiate polymerization. After polymerization was carried out for 4 hours while maintaining the reaction temperature at 80° C., the obtained copolymer was neutralized with 4.3 kg of glacial acetic acid. Then, while isopropanol is distilled off, 48.3 kg of ion-exchanged water is added to replace the inside of the system, and an aqueous solution (solid content concentration 35% by weight) was obtained as a dispersant.

After supplying the above dispersant from the injection port in the middle of the cylinder so that the solid content of the emulsion becomes 45% by mass, emulsification and dispersion treatment are performed, and a resin composed of a white olefin copolymer is discharged from the extruder outlet. An emulsion of particles was obtained.

(Preparation of coating liquid (c))
The butyl-modified polyethyleneimine aqueous solution (d) and the quaternary ammonium salt-containing acrylic resin aqueous solution (e) were mixed to prepare a coating solution (c). The blending amount of each aqueous solution is such that the solid content of the butyl-modified polyethyleneimine in the coating layer formed by the coating liquid (c) is 3 parts by mass, and the solid content of the quaternary ammonium salt-containing acrylic resin is 3.5. It was adjusted to be parts by mass.

[Example 1]
Thermoplastic resin (propylene homopolymer (trade name: Novatec PP FY-4, manufactured by Japan Polypropylene Corporation, MFR (230 ° C., 2.16 kg load): 5 g / 10 minutes, melting point: 165 ° C.))) 80 parts by mass , Filler (heavy calcium carbonate fine powder (manufactured by Bihoku Funka Kogyo Co., Ltd., product name: Softon #1800, volume average particle size: 1.8 μm))) 20 parts by mass, and a resin composition for the base layer Item (a) was prepared.

Thermoplastic resin (propylene homopolymer (trade name: Novatec PP FY-4, manufactured by Japan Polypropylene Corporation, MFR (230 ° C., 2.16 kg load): 5 g / 10 minutes, melting point: 165 ° C.))) 100 parts by mass , was used as the resin composition (b) for the intermediate layer.

The above resin composition (a) was melt-kneaded by an extruder set at 250° C., extruded, and cooled to 70° C. by a cooling device to obtain a single-layer unstretched film. After heating this unstretched film to 140° C., it was stretched 5 times in the longitudinal direction between rolls to obtain a longitudinally uniaxially stretched film. On the other hand, the above resin composition (b) was melt-kneaded in an extruder set at 250° C., extruded into a sheet shape and laminated on a longitudinally uniaxially stretched film. The obtained laminated film was heated to 155°C, stretched 8 times in the horizontal direction using a tenter stretching machine, and heat-treated at 165°C. Both surfaces of this laminated film were subjected to corona treatment at 40 W/m ² ·min using a discharge processor (manufactured by Kasuga Denki Co., Ltd.) to obtain a two-layer stretched film consisting of a substrate layer and an intermediate layer.

Next, the coating solution (c) was applied onto the intermediate layer to form a coating layer, and a label of Example 1 was obtained. The label of Example 1 is a three-layer laminate film consisting of a substrate layer/intermediate layer/coating layer (thickness of each layer: 90/10/-μm, total thickness: 100 μm, number of stretching axes of each layer: 1 axis/2 axes/ 1 axis).

[Example 2 and Comparative Example 1]
In Example 1, a filler (heavy calcium carbonate fine powder (manufactured by Bihoku Funka Kogyo Co., Ltd., product name: Softon #1800, volume average particle diameter: 1.8 μm)) was added to the resin composition (b) in the intermediate layer. Labels of Example 2 and Comparative Example 1 were obtained in the same manner as in Example 1 except that they were blended. Contents of the thermoplastic resin and filler in the resin composition (b) were changed as shown in Table 2. The thickness of each layer and the total thickness of the labels of Example 2 and Comparative Example 1 were the same as those of Example 1.

[Comparative Example 2]
A label of Comparative Example 2 was obtained in the same manner as in Example 1, except that no coating layer was formed. The thickness of each layer and the total thickness of the label of Comparative Example 2 were the same as those of Example 1.

[Comparative Example 3]
In Example 1, instead of the coating liquid (c), a water repellent agent (perfluoroalkyl acrylate copolymer (trade name: F-Tone GMW605, manufactured by Daikin Industries, Ltd.)) was applied to form a coating layer. A label of Comparative Example 3 was obtained in the same manner as in Example 1. The solid content of the water repellent in the coating layer was 5 parts by mass. The thickness of each layer and the total thickness of the label of Comparative Example 3 were the same as those of Example 1.

[Comparative Example 4]
In Example 1, a commercially available silane coupling agent (3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)) was added as a cross-linking agent to the coating solution (c). A label of Comparative Example 4 was obtained in the same manner as in Example 1, except that a coating layer was formed. The solid content of the cross-linking agent in the coating layer was 5 parts by mass. The thickness of each layer and the total thickness of the label of Comparative Example 4 were the same as those of Example 1.

[Comparative Example 5]
A label of Comparative Example 5 was obtained in the same manner as in Example 1, except that 30 parts by mass of emulsion (f) was further added to coating liquid (c) to form a coating layer. The thickness of each layer and the total thickness of the label of Comparative Example 5 were the same as those of Example 1.

Table 1 shows a list of raw materials for the labels of the above Examples and Comparative Examples.

[Label properties]
The surface smoothness and contact angle with water of the coating layer side of each label of Examples and Comparative Examples were measured.

(Smoothness)
The Oken smoothness of the surface of the coating layer of the label was measured according to JIS P 8155:2010 "Paper and paperboard-Smoothness test method-Oken method". For the measurement, a digital Oken type air permeability and smoothness tester (“EYO-55-1M” manufactured by Asahi Seiko Co., Ltd.) was used.

(contact angle)
23 ° C., in an environment of 50% relative humidity, using a fully automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., equipment name: DM-700), drop 1 μL of water on the surface of the coating layer of the label, Its contact angle was measured.

[evaluation]
The water drop prevention property when the label of each example and comparative example was attached to the outer surface of the bottle container and the ink adhesion property when printed on the coating layer were evaluated as follows.

(Drop prevention of water droplets)
A label of each example and comparative example was punched out to a size of 20 cm×8.5 cm and wrapped around the outer surface of a polyethylene terephthalate (PET) bottle body having a diameter of 5.5 cm and a height of 20 cm. The beginning and end of the wrapped label were glued together. Water was then added to the bottle until it reached the same height as the wrapped label, and cooled to a water temperature of 1-3°C. After cooling, as shown in FIG. 3, the bottle container 20 was put on the water receiving rubber 52 of the scale 51 placed in an environment with a temperature of 30° C. and a relative humidity of 70% RH for 30 minutes, and the mass was measured. The mass measured at this time was set in the scale 51 as a reference point (zero point).

As it was, the bottle container 20 was placed in an environment with a temperature of 30° C. and a relative humidity of 70% RH for 30 minutes to cause condensation. After 30 minutes, the mass (g) increased from the zero point of the weighing device 51 was taken as the amount of water droplets generated due to dew condensation (w1). The bottle container 20 was slowly moved from the scale 51 so that water droplets would not drop from the bottle container 20 . Then, the mass was measured by the measuring instrument 51 while only the water receiving rubber 52 and the water droplets accumulated therein were left, and the mass measured at this time was set as the reference point (zero point) on the measuring instrument 51 again. All water droplets on the water receiving rubber 52 were wiped off, and the mass (g) reduced from the zero point of the weighing device 51 was defined as the amount of water droplets falling (w2).

From the obtained water droplet generation amount (w1) and water droplet falling amount (w2), the water droplet falling rate (Wt) was calculated by the following formula.
Wt=w2/w1×100

From the calculated water droplet fall ratio (Wt), the water droplet fall prevention property was evaluated as follows.
A (Good): Water droplet falling ratio (Wt) is less than 15% B (Fair): Water droplet falling ratio (Wt) is 15% or more and 20% or less C (Poor): Water droplet falling ratio (Wt) is more than 20%

(Ink adhesion)
Solid printing was performed on the surface of the coating layer of each label of Examples and Comparative Examples with an ink coverage of 2.0 g/m ² . For printing, an ink for UV flexo (trade name: flexo 500, manufactured by T&KTOKA) was used. Next, UV irradiation was performed using a UV irradiation machine so that the irradiation intensity was 100 mJ/cm ² to obtain a sample for ink adhesion evaluation.

The obtained sample was conditioned at 23° C. and 50% RH for 1 day. A cellophane tape of 18 mm (trade name: CT-18, manufactured by Nichiban Co., Ltd.) was pasted on the printed image of the sample after humidity conditioning, and adhered with a finger. The tape was then peeled off with a peel angle of 180 degrees and a peel speed of 50 m/min. The peeling of the ink after peeling was observed, and the ink adhesion before promoting humidification was evaluated according to the following criteria.
A: No peeling of ink C: Peeling of ink and exposure of film surface

Table 2 shows the evaluation results.

As shown in Table 2, Examples 1 and 2, in which the surface smoothness and contact angle of the coating layer side of the label are within the specific ranges of the present invention, are excellent in water drop prevention properties and ink adhesion. was also highly sexual. On the other hand, Comparative Examples 1 and 5, which have a smoothness of less than 5000 seconds, cannot increase the contact angle, and are low in water drop prevention properties. Comparative Example 2, in which the intermediate layer is located on the surface, and Comparative Example 3, in which a coating layer made of a water-repellent agent is provided, have a contact angle with water within a specific range. ) It can be seen that the adhesiveness to the ink is low because the acrylic acid ester copolymer is not blended.

10 Label 11 Base layer 12 Coating layer 13 Intermediate layer 14 Printing layer 20 Bottle container 21 Container body 22 Cap 30 Water drop 40 Adhesive layer 51 Scale 52 Water receiving rubber

Claims (9)

A label having a substrate layer, an intermediate layer and a coating layer in this order,
The base layer and the intermediate layer are thermoplastic resin films,
The smoothness of the surface of the coating layer is 5000 seconds or more,
A label, wherein the surface of the coating layer has a contact angle with water of 85 to 104 degrees. The label according to claim 1, wherein the coating layer has a dynamic friction coefficient of 0.3 to 0.5. 3. The label according to claim 1, wherein the coating layer has an adhesive strength of 2 to 10 N/50 mm. 4. The label according to any one of claims 1 to 3, wherein the filler content in the intermediate layer is 5% by mass or less. The label according to any one of claims 1 to 4, wherein the coating layer contains an ethyleneimine polymer and a (meth)acrylate copolymer. 6. The label according to claim 5, wherein the content of said ethyleneimine polymer in said coating layer is 30 to 70% by mass. 7. The label according to claim 5, wherein the content of the (meth)acrylic acid ester copolymer in the coating layer is 30 to 70% by mass. The label according to any one of claims 1 to 7, wherein the substrate layer is a porous stretched film containing an olefin resin and a filler. A bottle container, wherein the label according to any one of claims 1 to 8 is attached to the surface of the bottle body.

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