JP2018060185A - In-mold label and container with label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-mold label stuck to a container made from a polar resin irrespective of use of a non-polar resin in an adhesive layer, and to provide an in-mold label which has a high adhesion strength even on a low temperature adhesion condition of stretch blow molding, and prevents the label from peeled from a container with label even when the container is brought into contact with water.SOLUTION: There are provided an in-mold label which has a low melting point resin layer (B) on one surface of a thermoplastic resin film (A), where the low melting point resin layer (B) contains a polyethylene-based resin, a melting point of the polyethylene-based resin is 60-110°C, a thickness of the low melting point resin layer (B) is 1.5-15 μm, and the surface of the low melting point resin layer (B) is subjected to activation treatment; and a container with label.SELECTED DRAWING: None

Description

  The present invention relates to an in-mold label and a labeled container.

Conventionally, in order to integrally mold a resin-molded product with a label, a blank or a label is previously inserted into the mold, and then the mold is molded by a method such as injection molding, hollow molding, differential pressure molding, or foam molding. A resin molded product is molded by the above method, a label is attached to the resin molded product, and painting is performed.
As such a label, for example, a label obtained by laminating a polypropylene film containing inorganic fine powder as a base material, and laminating an adhesive layer made of polyethylene on the base material and having a thickness of 1 to 10 μm, and the label as polyethylene A labeled container obtained by sticking to a container is known (for example, see Patent Document 1).

  On the other hand, an in-mold label having an adhesive layer made of polyethylene cannot be attached to the surface of a container obtained by blow-molding a preform made of polyester resin represented by polyethylene terephthalate. As an in-mold label to be attached to a polyester resin container, for example, a stretched polypropylene film having a heat seal layer containing an ethylene-vinyl acetate copolymer, a label having an adhesive layer thickness of 25 to 50 μm, and the label as a polyester A labeled container obtained by sticking to a container is known (for example, see Patent Document 2).

  On the other hand, an in-mold label having an adhesive layer with a thickness of about 25 μm using linear low density polyethylene polymerized by a single site catalyst on one surface of a polymer film is extrusion blow molding (also referred to as direct blow molding). Is known to stick to a polyester container (for example, see Patent Document 3).

Japanese Patent Publication No. 02-007814 JP 2004-136486 A JP 10-315410 A

When the present inventors examined with respect to the method of patent document 2, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid alkyl copolymer, carboxylic acid modified polyolefin resin, thermoplastic polyester type A resin (hereinafter sometimes referred to as “polar resin”) containing many heteroatoms (atoms other than hydrogen atoms and carbon atoms) in the main chain or side chain, such as a resin or a thermoplastic polyamide-based resin, is used for the adhesive layer. In some cases, the co-extrusion with the base material or the molding method by heat laminating the base material has problems such as coloring due to thermal decomposition of the adhesive layer resin and curling due to the thickness of the adhesive layer.
In addition, when applying polar resins that are considered to have high adhesion to polyester, these resins do not dissolve in water due to the high content of ethylene polymerized units, and it is necessary to use them as paints containing polar resins as emulsions. There is. A surfactant is generally used to make the polar resin into an emulsion. Then, when the obtained container with a label is brought into contact with water, there is a problem that the label is immediately peeled off from the container.

In the case of stretch blow molding, the amount of heat of the parison (original made of thermoplastic resin for use in blow molding) is less than the amount of heat of the parison of direct blow molding, so it is necessary to select a resin that can be fused with a small amount of heat. Naturally, a polar resin having a melting point of 130 ° C. or lower is selected. Then, due to the thickness of the adhesive layer, when blocking a plurality of in-mold labels at a room temperature and when applying a load, a plurality of in-mold labels are stacked and punching is performed. It was found that cut blocking occurs in which the labels are not separated from each other.
When the present inventors examined stretch blow molding in place of direct blow molding for the label produced by the production method described in Patent Document 3, since the parison has a small amount of heat, the adhesive strength decreased.

  Therefore, the present inventors use a resin (hereinafter sometimes referred to as “non-polar resin”) containing almost no hetero atoms (atoms other than hydrogen atoms and carbon atoms) in the main chain or side chain in the adhesive layer. Nevertheless, an object of the present invention is to provide an in-mold label that is adhered to a polar resin container and an in-mold label that does not easily peel from the container even when the labeled container is brought into contact with water. That is, the problem to be solved by the present invention is that an in-mold label adhered to a polar resin container in spite of using a non-polar resin for the adhesive layer, and further bonded under low temperature bonding conditions of stretch blow molding. It is to provide an in-mold label that has high strength and is difficult to peel from the container even when the container with the label is brought into contact with water.

  As a result of intensive studies, the present inventors have selected a nonpolar resin as an adhesive layer, laminated a low melting point resin that melts by the heat of stretch blow molding, and then activated the surface of the low melting point resin layer. It has been found that the above-mentioned problems can be solved by achieving the intended purpose.

That is, the present invention, which is a means for solving the above problems, and preferred embodiments thereof are as follows.
[1] A low melting point resin layer (B) is provided on one surface of the thermoplastic resin film (A),
The low melting point resin layer (B) contains a polyethylene resin,
The melting point of the polyethylene resin is 60 to 110 ° C.
The thickness of the low melting point resin layer (B) is 1.5 to 15 μm,
An in-mold label, wherein the surface of the low melting point resin layer (B) is activated.
[2] The in-mold label according to [1], wherein the polyethylene-based resin is a copolymer of 95 mol% or more and less than 100 mol% of ethylene and more than 0 mol% and 5 mol% or less of a monomer copolymerizable with ethylene.
[3] The in-mold label according to [1] or [2], wherein a corona discharge treatment mark is present on the surface of the low melting point resin layer (B).
[4] The in-mold label according to any one of [1] to [3], wherein the surface tension of the surface of the low melting point resin layer (B) is 45 to 75 mN / m.
[5] The in-mold according to any one of [1] to [4], wherein the thermoplastic resin film (A) has an ink receiving layer (C) on a surface not having the low melting point resin layer (B). label.
[6] A labeled container in which the in-mold label according to any one of [1] to [5] is attached to a surface of a polar resin container.
[7] The labeled container according to [6], wherein the polar resin is a polyester resin.

According to the present invention, an in-mold label that is attached to a polar resin container in spite of using a non-polar resin for the adhesive layer, and also has a high adhesive strength even under low-temperature bonding conditions of stretch blow molding, and with a label It is possible to provide an in-mold label in which the label is difficult to peel from the container even when the container is brought into contact with water.
Moreover, according to this invention, even if it makes it contact with water using the said in-mold label, a labeled container which cannot peel easily from a container can be provided.

  The description of the constituent elements described below is made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present invention, “(meth) acrylic acid” refers to both acrylic acid and methacrylic acid. “Heteroatom” refers to an atom other than a hydrogen atom and a carbon atom. Moreover, the numerical range represented using "to" means the range which includes the numerical value described before and behind "to" as a lower limit and an upper limit, respectively. Further, “mainly contained” means containing most by mass ratio. In addition, an organic substance having 2 carbon atoms such as ethane or ethylene may be represented by the number of carbon atoms such as C2. The melting point of the thermoplastic resin is the melting peak temperature according to JIS K7121: 1987.

<In-mold label>
The in-mold label of the present invention has a low melting point resin layer (B) on one surface of the thermoplastic resin film (A),
The low melting point resin layer (B) contains a polyethylene resin,
The melting point of the polyethylene resin is 60 to 110 ° C.
The thickness of the low melting point resin layer (B) is 1.5 to 15 μm,
The surface of the low melting point resin layer (B) is activated.
Below, the preferable aspect of the in-mold label of this invention is demonstrated.

[Thermoplastic resin film (A)]
In this invention, a thermoplastic resin film (A) becomes a support body in an in-mold label, and is not specifically limited. It is preferable that the thermoplastic resin film (A) gives the in-mold label a rigidity (stiffness) that allows handling such as printing and insertion in a mold.

(Thermoplastic resin)
Examples of the thermoplastic resin contained in the thermoplastic resin film (A) include olefin resins such as polypropylene resin, polymethyl-1-pentene, and ethylene-cyclic olefin copolymer; polyesters such as polyethylene terephthalate resin and polybutylene terephthalate resin. Polyvinyl chloride resin; Polyamide resins such as nylon-6, nylon-6, 6, nylon-6, 10, nylon-6, 12; polystyrene; polycarbonate, and the like. Among these, it is preferable that a polypropylene resin and a polyethylene terephthalate resin are mainly included from the viewpoint of ease of production. The thermoplastic resin contained in the thermoplastic resin film (A) from the viewpoint of causing a difference in melting point with the low melting point resin layer (B) and preventing the thermoplastic resin film (A) from being deformed unnecessarily during in-mold molding. Is preferably a thermoplastic resin having a melting point 15 ° C. higher than the melting point of the polyethylene resin contained in the low melting point resin layer (B). Specifically, a thermoplastic resin having a melting point in the range of 130 to 280 ° C is preferable. Two or more of these thermoplastic resins can be mixed and used.

(Inorganic fine powder and organic filler)
The thermoplastic resin film (A) may contain an inorganic fine powder or an organic filler. By stretching the thermoplastic resin film (A) containing the inorganic fine powder, the thermoplastic resin film (A) can be made white opaque. As a result, the visibility of printing provided on the in-mold label can be improved. In addition, when the thermoplastic resin film (A) does not contain the inorganic fine powder, the label is not conspicuous in the labeled container, and can be displayed as if it is directly printed on the container. Depending on the design, the thermoplastic resin film (A) containing inorganic fine powder and the thermoplastic resin film (A) not containing inorganic fine powder can be properly used.

Inorganic fine powders include calcium carbonate (preferably heavy calcium carbonate), calcined clay, silica, diatomaceous earth, white clay, talc, titanium oxide (preferably rutile titanium dioxide), barium sulfate, alumina, zeolite, mica, Examples thereof include sericite, bentonite, sepiolite, vermiculite, dolomite, wollastonite, and glass fiber.
As the inorganic fine powder, one whose surface is treated with a fatty acid or the like can be used.

The thermoplastic resin film (A) may contain an organic filler. Even when the thermoplastic resin film (A) contains an organic filler, the in-mold label can be whitened and opaqued, and the effect of facilitating the visual recognition of printing is achieved.
The organic filler is the melting point or glass transition point of the thermoplastic resin mainly contained in the thermoplastic resin film (A) (50% by mass or more based on the total mass of the thermoplastic resin when two or more types of thermoplastic resins are included). It is preferable that the resin has a high melting point or glass transition point.
When the thermoplastic resin mainly contained in the thermoplastic resin film (A) is a propylene resin, the melting point or glass transition point of the organic filler is preferably 120 to 300 ° C. Suitable organic fillers include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyamide, polycarbonate, polystyrene, cyclic olefin homopolymer, ethylene-cyclic olefin copolymer, polyethylene sulfide, polyimide, polymethacrylate, polyethyl ether ketone, Examples include polyphenylene sulfide and melamine resin.

For the thermoplastic resin film (A), one kind selected from inorganic fine powder or organic filler may be used alone, or two or more kinds selected may be used in combination. Good.
When designing the thermoplastic resin film (A) to include inorganic fine powder or organic filler, the addition ratio of the inorganic fine powder or organic filler to the total mass of the thermoplastic resin film (A) is preferably 10 to 70% by mass. 10-60 mass% is more preferable, and 15-50 mass% is further more preferable. When the addition rate of the inorganic fine powder or the organic filler is equal to or higher than the lower limit of the above range, the thermoplastic resin film (A) is likely to become white opaque, and the addition rate of the inorganic fine powder or the organic filler is less than the upper limit of the above range. If there is, the molding tends to be uniform.

The volume average particle diameter of the inorganic fine powder or the average dispersed particle diameter of the organic filler is preferably 0.01 to 15 μm, more preferably 0.05 to 5 μm, and more preferably 0.1 to 2. 0 μm is more preferable. Accordingly, there is a tendency that voids are easily obtained by stretch molding, and the in-mold label is easily made opaque. When the volume average particle diameter of the inorganic fine powder or the average dispersed particle diameter of the organic filler is not less than the lower limit of the above range, the thermoplastic resin film (A) can easily achieve white opacification, and the volume average particle diameter is in the above range. If it is less than or equal to the upper limit value, the molding becomes uniform, and the strength of the thermoplastic resin film (A) becomes sufficient.
The volume average particle size of the inorganic fine powder and the average dispersed particle size of the organic filler are cumulative values measured by a particle measuring device such as a laser diffraction particle measuring device “Microtrack” (trade name, manufactured by Microtrack Bell Co., Ltd.). Observation of particle diameter corresponding to 50% (cumulative 50% particle diameter), observation of primary particle diameter with a scanning electron microscope (in the present invention, the average value of 100 particles is an average particle diameter), conversion from specific surface area (present invention) Then, the specific surface area was measured using a powder specific surface area measuring device SS-100 manufactured by Shimadzu Corporation.

(Additive)
In addition, the thermoplastic resin film (A) is optionally provided with a sterically hindered phenol-based, phosphorus-based, amine-based or sulfur-based antioxidant; a sterically hindered amine-based, benzotriazole-based or benzophenone-based light stabilizer. Additives such as dispersants, lubricants and antistatic agents can be used. It is preferable to add 0.001 to 1% by mass of each of the above-mentioned various additives independently with respect to the total mass of the thermoplastic resin film (A). When the additive amount of various additives is equal to or higher than the lower limit value of the above range, the effect of the additive tends to be exhibited, and when the additive amount of various additives is equal to or lower than the upper limit value of the above range, coloring or printability decreases. It becomes difficult to do.

  The thermoplastic resin film (A) may be a single layer or two or more layers. By forming two or more layers, the in-mold label can be provided with functions such as white opaqueness of the label, printing ink acceptability, heat insulation, and accompanying good in-mold moldability.

  20-200 micrometers is preferable and, as for the thickness of a thermoplastic resin film (A), 40-150 micrometers is more preferable. As a result, the label is less likely to be wrinkled at the time of printing, and can be easily fixed at a proper position when inserted into the mold, so that the effect of increasing the drop-proof strength associated with a decrease in the strength of the label boundary portion of the labeled container can be obtained.

When these conditions are taken into consideration, suitable transparent thermoplastic resin film (A) does not include fine inorganic powder, polypropylene-based unstretched film (CPP film), polypropylene-based biaxially stretched film (BOPP film), polyethylene Examples thereof include a terephthalate-based unstretched film (CPET film) and a polyethylene terephthalate-based biaxially stretched film (BOPET film).
Moreover, as a suitable opaque thermoplastic resin film (A), a CPP film, a BOPP film, a CPET film, a BOPET film, and synthetic paper containing an inorganic fine powder are mentioned.

[Low melting point resin layer (B)]
The in-mold label of the present invention has a low melting point resin layer (B) on one surface of the thermoplastic resin film (A). The low melting point resin layer (B) provides sufficient adhesion strength with a molded product even under low temperature adhesion conditions in stretch blow molding.

  The thickness of the low melting point resin layer (B) is 1.5 to 15 μm. When the thickness is 1.5 μm or more, the adhesive strength is hardly lowered. If the thickness is 15 μm or less, coloring of the adhesive layer and curling of the label are less likely to occur, and it is not necessary to deepen the embossing to escape the air that has entered between the label and the container during in-mold molding, affecting the appearance. It becomes difficult to do. The thickness of the low melting point resin layer (B) is preferably 2 to 5 μm, and more preferably 2 to 3 μm.

(Polyethylene resin)
In the present invention, the melting point of the polyethylene resin contained in the low melting point resin layer (B) is 60 to 110 ° C. When the melting point is 60 ° C. or higher, blocking (particularly cut blocking) is difficult to occur, and when the melting point is 110 ° C. or lower, the low melting point resin layer (B) is easily melted during in-mold molding, and the adhesive strength is easily increased. From the viewpoint of achieving both label blocking and adhesive strength of the labeled container, the melting point of the polyethylene resin contained in the low melting point resin layer (B) is preferably 70 to 100 ° C, and more preferably 75 to 90 ° C.
The polyethylene resin contained in the low melting point resin layer (B) may be an ethylene homopolymer; it may be a copolymer of ethylene and a monomer copolymerizable with ethylene. The polyethylene resin contained in the low melting point resin layer (B) is preferably a copolymer of ethylene and a monomer copolymerizable with ethylene.
Monomers that can be copolymerized with ethylene include α-olefins having 3 to 10 carbon atoms (preferably 3 to 8 carbon atoms), monomers having no hetero atoms such as styrene, vinyl acetate, (meth) acrylic acid, and alkyl groups. And monomers having a heteroatom such as (meth) acrylic acid alkyl ester having 1 to 8 carbon atoms and maleic anhydride.
From the viewpoint of improving water resistance, it is preferable that the polyethylene-based resin does not basically have a hetero atom. From the viewpoint of improving water resistance, it is preferable to contain 95 mol% or more, more preferably 97 mol% or more of a monomer-derived structural unit having no hetero atom. Similarly, the polyethylene-based resin preferably contains 5 mol% or less of a structural unit derived from a monomer having a hetero atom, more preferably 3 mol% or less, and particularly preferably does not contain at all.
Especially, it is preferable that a polyethylene-type resin contains 80 mol% or more of structural units derived from ethylene. From the viewpoint of increasing the adhesive strength at low temperatures, the polyethylene resin more preferably contains 95 mol% or more and less than 100 mol% of structural units derived from ethylene, and particularly preferably contains 97 mol% or more and less than 100 mol%.
Further, from the viewpoint of inhibiting blocking, it is preferable that the structural unit derived from a monomer copolymerizable with ethylene is included more than 0 mol% and 5 mol% or less, and more preferably more than 0 mol% and 3 mol% or less.

For the above reasons, among polyethylene resins, low density polyethylene, linear low density polyethylene, and ethylene-propylene copolymer are particularly preferable, and linear low density polyethylene is most preferable. These polyethylene resins may be used alone or in combination of two or more.
Examples of the linear low density polyethylene include those synthesized by a multisite catalyst typified by a Ziegler type catalyst and those synthesized by a single site catalyst typified by a metallocene catalyst. From the viewpoint of controlling the melting point of the polyethylene resin contained in the low melting point resin layer (B) within the above range, those synthesized by a single site catalyst are preferable. Among the catalysts, transition metals such as Zr, Ti, Hf and the like A so-called metallocene catalyst comprising an unsaturated ring such as a cyclopentadienyl ring or an indenyl ring is preferred.
Moreover, from the viewpoint of cut-blocking suppression, the ratio Mw / Mn between the weight average molecular weight and the number average molecular weight of the linear low density polyethylene is preferably 3.5 or less.
Various additives such as an antioxidant, a lubricant, an antiblocking agent, and an antistatic agent can be blended with the polyethylene resin as necessary.

(Surface activation treatment)
In the present invention, the surface of the low melting point resin layer (B) is activated in the state of the in-mold label. When the melting point of the low melting point resin layer (B) is melted by the heat of the parison, if the surface of the low melting point resin layer (B) is activated, the familiarity with the parison is good, and the surface easily wets and spreads. It is inferred that the adhesion between the resin layer (B) and the container is improved. Thereby, the label adhesive strength of a labeled container can be made high.
Examples of the activation treatment include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, and ozone treatment. Of these, corona discharge treatment and plasma treatment are preferred from the viewpoint of treatment effects, and corona discharge treatment and flame treatment are preferred from the viewpoint of using simple equipment.
Activation amount in the case of corona discharge treatment, from the viewpoint of obtaining the effect of corona discharge treatment, 600~12,000J / m ² (10~200W · min / m ²⁾ are preferred, 1200~9000J / m ² ( 20 to 150 W · min / m ² ) is more preferable. When the processing amount is within this range, the label adhesive strength is unlikely to decrease.
Activation amount in the case of plasma treatment and flame treatment is preferably 8,000~200,000J / m ² from the viewpoint of obtaining the effects of the activation treatment, and more preferably 20,000~100,000J / m ^2. When the processing amount is within this range, the label adhesive strength is unlikely to decrease. Moreover, the surface after a corona discharge process may have a corona discharge process trace. Corona discharge treatment traces include surface pinholes due to arcing, processing unevenness due to uneven distribution of streamers (surface tension varies depending on location), and post-treatment charging. In the charging due to corona discharge, when a mixture of two types of toners having different polarities and colors is sprinkled on the surface, toners having different polarities are unevenly distributed on the surface to form a mottled pattern of two colors. In the present invention, it is preferable that corona discharge treatment traces exist on the surface of the low melting point resin layer (B).

  Examples of the flame treatment include activation treatment by blowing ionized plasma in a flame generated when a combustible gas such as natural gas or propane is burned by a burner to the surface of the low melting point resin layer (B). Examples of the frame processing apparatus include an apparatus provided with a burner provided on the low melting point resin layer (B) side of the in-mold label and having a nozzle row parallel to the in-mold label.

  In plasma treatment, a gas in which hydrogen, oxygen, nitrogen, air or the like is mixed with a gas containing an inert gas such as argon, helium, or neon as a main component is passed through a glow discharge region generated between the discharge electrode and the counter roll. There is a method in which an excited inert gas that is excited electronically, removes charged particles, and is electrically neutral is sprayed on the surface of the in-mold label. The plasma processing apparatus includes a pair of counter electrodes provided on the surface side of the low melting point resin layer (B), and a counter electrode roll disposed to face these counter electrodes with an in-mold label interposed therebetween. Examples of the electrode include a flat plate shape, a convex surface on the opposite surface, and a roll shape that can be rotated. The counter roll is preferably coated with an insulator.

  If the surface of the low-melting-point resin layer (B) is activated, the surface tension obtained using a test liquid mixture according to JIS K6768: 1999 “Plastic-film and sheet-wetting tension test method” is 40 mN. / M or more. From the viewpoint of expressing the adhesive effect of the present invention, the surface tension of the low melting point resin layer (B) is preferably 45 to 75 mN / m, more preferably 45 to 72 mN / m, and still more preferably 55 to 70 mN / m. This increases the adhesive strength of the labeled container. It is presumed that the wetting and spreading of the thermoplastic resin composition of the low melting point resin layer (B) with respect to the parison is not good whether the surface tension is outside or above the above range.

The activation treatment is preferably an oxidation treatment, and the number of oxygen atoms / carbon atoms (= O / C ratio) determined by X-ray photoelectron spectroscopy (XPS) on the surface of the low melting point resin layer (B) after the activation treatment. Is preferably 0.006 to 0.1, and more preferably 0.015 to 0.1. This increases the adhesive strength of the labeled container. It is estimated that the wetting spread of the thermoplastic resin composition of the low melting point resin layer (B) with respect to the parison is good when the O / C ratio is within the above range.
In addition, since the activation treatment effect tends to gradually decrease with time, the activation treatment may be performed immediately before in-mold molding from the viewpoint of suppressing variation in the adhesive strength of the labeled container for each label production lot. .

  The surface of the low melting point resin layer (B) preferably has irregularities from the viewpoint of promptly discharging air that has entered between the label and the parison during in-mold molding. Although a well-known method can be used for the provision of unevenness, generally the embossing roll can be preferably used.

[Ink receiving layer (C)]
The in-mold label of the present invention preferably has an ink receiving layer (C) on the surface on which the thermoplastic resin film (A) does not have the low melting point resin layer (B). The ink receiving layer (C) has the effect of improving the printability of the in-mold label, particularly the ink transferability and the ink adhesion.
The ink receiving layer (C) preferably contains a binder and / or an antistatic agent. The ink receiving layer (C) preferably further contains a crosslinking agent. Further, the ink receiving layer (C) can contain an antiblocking agent, a colorant, an antifoaming agent, an antifungal agent and the like, if necessary.

The binder is not particularly limited as long as it has adhesiveness and can be applied to the surface of the thermoplastic resin film (A).
Examples of the binder include ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid copolymer and metal salts thereof (Zn, Al, Li, K, Na, etc.), ethylene / (meth) acrylic acid (C1-8). ) Ethylene copolymers such as alkyl ester copolymers; acid-modified polyolefins such as maleic acid-modified polyethylene, maleic acid-modified polypropylene, maleic acid-modified ethylene / vinyl acetate copolymers; monohydroxy (C3-6) alkyl-modified polyethylene Hydroxyl-modified polyolefin such as chlorinated polyolefin; Polyurethane such as polyester polyurethane and polycarbonate polyurethane; Polyethyleneimine such as polyethyleneimine and poly (ethyleneimine-urea) and its modified product; Ethyleneimine adduct of polyamine polyamide, polyamine Polyamide various (alkyl, cycloalkyl, aryl, aralkyl, benzyl, cyclopentyl) include modified polyamine polyamide modified products and the like.
When imparting water resistance to the ink receiving layer (C), a water dispersible (emulsion) binder can be selected.

An antistatic agent is applicable to the surface which does not have the low melting point resin layer (B) of an in-mold label. There is no particular limitation as long as antistatic properties can be imparted to the surface of the thermoplastic resin film (A) or the ink receiving layer (C) constituting this surface.
Antistatic agents include low molecular weight organic compounds such as stearic acid monoglyceride, alkyldiethanolamine, sorbitan monolaurate, alkylbenzene sulfonate and alkyl diphenyl ether sulfonate; ITO (indium doped tin oxide), ATO (antimony doped oxidation) Tin), conductive inorganic compounds such as graphite whiskers; so-called electron conductive polymers that exhibit conductivity by pi electrons in the molecular chain such as polythiophene, polypyroyl, polyaniline; polyethylene glycol, polyoxyethylene alkyl ether, polyoxyethylene diamine, etc. Nonionic polymer type antistatic agent of quaternary ammonium such as polyvinylbenzyltrimethylammonium chloride, polydimethylaminoethyl methacrylate Type copolymer; alkali metal salt-containing polymers such as an alkali metal ion additives, etc. to the alkylene oxide group and / or hydroxyl group-containing polymer.
The surface resistivity of the in-mold label surface is preferably 1 × 10 ² Ω to 1 × 10 ¹³ Ω, and more preferably 1 × 10 ⁶ Ω to 1 × 10 ¹² Ω.

The crosslinking agent reacts with the binder and / or antistatic agent, or encapsulates the binder and / or antistatic agent in the network formed by the crosslinking agent, and the binder and / or antistatic agent is placed on the surface of the in-mold label. It works to fix. As a result, for example, there is an effect of improving adhesion and water resistance of printing applied to the in-mold label.
Examples of the crosslinking agent include bifunctional or higher functional materials having a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an aldehyde group, an oxazoline skeleton, a carbodiimide skeleton, and the like as a reactive functional group.
Among them, bisphenol A-epichlorohydrin resin, polyamine polyamide epichlorohydrin resin, aliphatic epoxy resin, epoxy novolac resin, cycloaliphatic epoxy resin, brominated epoxy resin, etc. are preferable, and polyamine polyamide epichlorohydrin adduct, monofunctional to polyfunctional glycidyl. Ethers and glycidyl esters are more preferred.

[In-mold label manufacturing method]
There is no limitation on the method for producing the in-mold label.
It is preferable to manufacture the low melting point resin layer (B) by laminating it on one surface of the thermoplastic resin film (A). The method for laminating the low melting point resin layer (B) on one surface of the thermoplastic resin film (A) is not particularly limited.
Moreover, a thermoplastic resin film (A) can also be made into a multilayer structure. Examples of the method for forming a single layer film include extrusion molding (cast molding) using a T die, inflation molding using an O die, and calendar molding using a rolling roll. As a method of forming a multilayer film, the T die and the O die are configured as a multilayer die. Then, the thermoplastic resin composition used for each layer is supplied to different extruders and melted, and the thermoplastic resin composition discharged from each extruder is supplied to the multilayer die and laminated in the die. Discharge in film form.

(Lamination method of low melting point resin layer (B))
Examples of the method for laminating the low melting point resin layer (B) on one surface of the thermoplastic resin film (A) include a co-extrusion method, an extrusion laminating method, and a film laminating method.
The co-extrusion method supplies the multilayer die with a thermoplastic composition for the thermoplastic resin film (A) and a thermoplastic composition for the low-melting-point resin layer (B) (each of which may be a plurality). In order to laminate and extrude in a multilayer die, lamination is performed simultaneously with molding.
In the extrusion laminating method, the thermoplastic resin film (A) is formed first, and the melted low melting point resin layer (B) is laminated thereon. Therefore, the molding and lamination are performed in separate steps.
In the film laminating method, the thermoplastic resin film (A) and the low-melting point resin layer (B) are each formed into a film and bonded together via an adhesive.
Among these lamination methods, the coextrusion method is preferable from the viewpoint that each layer can be firmly bonded.

(Stretching)
Each of the thermoplastic resin film (A) and the low melting point resin layer (B) may be unstretched or may be stretched in at least one axial direction.
For example, if the thermoplastic resin film (A) is non-stretched, the shape followability of the labeled container can be improved. On the other hand, if the thermoplastic resin film (A) is stretched, it is lightweight and excellent in thickness uniformity.
Stretching methods include longitudinal stretching using the peripheral speed difference of the roll group, rolling, lateral stretching using a tenter oven, sequential biaxial stretching combining longitudinal stretching and lateral stretching, and simultaneous use of a combination of a tenter oven and a linear motor. Biaxial stretching, simultaneous biaxial stretching by a combination of a tenter oven and a pantograph can be exemplified. Moreover, when using an inflation shaping | molding method, simultaneous biaxial stretching by adjustment of the amount of blowing air can be mentioned.

The draw ratio at the time of drawing is not particularly limited, and is appropriately determined in consideration of the physical properties of the in-mold label and the drawing characteristics of each layer (particularly the thermoplastic resin film (A)).
In the case of uniaxial stretching, the stretching ratio in the case of using a propylene-based resin as the thermoplastic resin of the thermoplastic resin film (A) is preferably 1.2 to 12 times, and more preferably 2 to 10 times. In the case of biaxial stretching, the area magnification is preferably 1.5 to 60 times, and more preferably 4 to 50 times.
In the case of uniaxial stretching, the stretching ratio in the case of using other thermoplastic resins such as polyethylene resins and polyester resins is preferably 1.2 to 10 times, and more preferably 2 to 5 times. In the case of biaxial stretching, the area magnification is preferably 1.5 to 20 times, and more preferably 4 to 12 times.

The stretching temperature is appropriately determined in consideration of the stretching characteristics of each layer (particularly the thermoplastic resin film (A)). Among them, the temperature is preferably from the glass transition temperature of the thermoplastic resin mainly contained in the thermoplastic resin film (A) to the melting point of the crystal part.
When the thermoplastic resin mainly contained in the thermoplastic resin film (A) is a propylene homopolymer (melting point: 155 to 167 ° C.), the stretching temperature is preferably 1 to 70 ° C. lower than the melting point. The stretching temperature is preferably 100 to 166 ° C.
The stretching speed is preferably 20 to 350 m / min.

(Lamination of ink receiving layer (C))
-Solvent-
The ink receiving layer (C) is preferably formed by applying a coating liquid. The solvent that forms the coating liquid is water; water-soluble solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, and methyl ethyl ketone; water-insoluble solvents such as ethyl acetate, toluene, and xylene from the viewpoint of easy process control Is mentioned.
The coating liquid is preferably dissolved or dispersed homogeneously in the above solvent and used as a solution or dispersion. Among these, from the viewpoint of safety and odor, it is more preferable to use any of the above components as a water-soluble or water-dispersible substance in the form of an aqueous solution or an aqueous dispersion.
From the viewpoint of reducing the drying load, the solid content concentration in the coating liquid is preferably 0.1% by mass or more, and more preferably 0.2% by mass or more. Moreover, 20 mass% or less is preferable from a viewpoint of obtaining a uniform coating surface, and 10 mass% or less is more preferable.

-Coating-
Examples of the coating method include a method using a coating apparatus such as a gravure coater, a micro gravure coater, a reverse coater, a blade coater, a Mayer bar coater, and an air knife coater.
When water or a water-soluble organic solvent is used as the solvent, it has a low melting point on the surface on which the coating solution for the thermoplastic resin film (A) is applied in advance, from the viewpoint of uniform coating while suppressing the repelling of the coating solution. It is preferable to perform activation treatment similar to the surface of the resin layer (B). Moreover, it is also preferable to apply the coating liquid on one side of the thermoplastic resin film (A) in advance and dry the coating layer to remove the solvent.

-Coating amount-
Ink receiving layer (C), it is ^{preferably, 0.01g / m 2 ~5g / m} 2 as a solid coating amount per one side after drying is 0.01g / m ² ~7g / m ² Is more preferable, and 0.05 g / m ² to ³ g / m ² is particularly preferable. When the coating amount of the ink receiving layer (C) is within the above range, the transferability and adhesion of the ink are improved. When the coating amount of the ink receiving layer (C) is less than or equal to the above upper limit value, the in-mold label is less likely to curl, and the ink adhesion is less likely to deteriorate due to cohesive failure in the ink receiving layer (C). On the other hand, when the coating amount of the ink receiving layer (C) is not less than the above lower limit, the transferability and adhesion of the ink are easily developed.

[Processing of in-mold labels]
(Printing and decoration)
The in-mold label of the present invention can be printed.
Usually, it can print on the surface which does not provide the low melting-point resin layer (B) of a thermoplastic resin film (A). Examples of the print information include a barcode, a manufacturer, a sales company name, a character, a product name, and a usage method.
Moreover, printing can also be performed on the low melting point resin layer (B). When the thermoplastic resin film (A) is transparent, the printed information on the low-melting point resin layer (B) is not present in the outermost layer in the labeled container, so that the effect of excellent durability is achieved. Further, when the thermoplastic resin film (A) is opaque, the printing information cannot be visually recognized in the container with the label, and the printing becomes visible when the label is broken.
Examples of the printing method include gravure printing, offset printing, flexographic printing, seal printing, and screen printing.
Further, the in-mold label may be decorated with a transfer foil, a hologram, or the like. Security elements such as threads are also included in the decoration. You may give both printing and decoration.

(Punching)
The in-mold label is preferably separated into a necessary shape and size by punching before or after printing and decoration. From the viewpoint of not easily damaging printed and decorated information, it is preferable to perform punching after printing and decoration. The punched in-mold label may be affixed to the entire surface of the plastic container, or may be a partial affixed partly. For example, the in-mold label may be used as a blank label surrounding the side surface of a cup-shaped plastic container attached by injection molding, or the surface of a bottle-shaped plastic container attached by hollow molding It may also be used as a label attached to the back surface.

<Container with label>
In the labeled container of the present invention, the in-mold label of the present invention is adhered to the surface of a polar resin container.
Below, the preferable aspect of the container with a label of this invention is demonstrated.

[Manufacturing method of labeled container]
(In-mold molding)
There is no limitation on the method of in-mold molding, that is, the method of attaching an in-mold label to the surface of the polar resin container.
Although the in-mold label of the present invention uses the low melting point resin layer (B) containing a polyethylene-based resin that basically has no hetero atom (which is a nonpolar resin), the low melting point resin layer The surface of (B) has a property of sticking (preferably heat-sealing) to a polar resin (for example, a polyester resin typified by polyethylene terephthalate).

(Material of container)
In the present invention, a polar resin container is used. Examples of the material for the in-mold molded polar resin container include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polybutylene succinate, and polylactic acid. In addition, since the adhesive mechanism is the same as that of the polyester-based resin, the materials for the container to be molded in-mold are polycarbonate-based resin, acrylonitrile-styrene (AS) resin, acrylonitrile-butylene-styrene (ABS) resin, methyl methacrylate- Other polar resins such as styrene (MS) resin are also included.
The material of the container may be transparent and / or natural without pigments or dyes, or may be opaque and / or colored with pigments or dyes.
The body of the container may have a perfect cross section or may be oval or rectangular. When the body has a rectangular cross section, the corners preferably have a curvature. From the viewpoint of strength, the cross section of the body is preferably a perfect circle or an elliptical shape close to a perfect circle, and more preferably a perfect circle.

(Molding method)
As a molding method using a polar resin (for example, polyethylene terephthalate), there is a stretch blow molding in which a preform that is heated as a parison is used and pressed onto a mold inner wall with a rod and compressed air. The in-mold label of the present invention is particularly useful for stretch blow molding because of its high adhesive strength even under low temperature bonding conditions for stretch blow molding.
However, the in-mold label of the present invention can be used not only for stretch blow molding but also for direct blow molding, injection molding, differential pressure molding and the like.
For example, in hollow molding, after placing the low melting point resin layer (B) side of the label in the cavity of the molding die so as to face the cavity side of the mold (in contact with the resin of the container material), the mold is drawn by suction or static electricity. Secure to the inner wall. Next, a resin parison serving as a container molding material is guided between the molds, clamped and then hollow molded by a conventional method, and the mold is opened to form a labeled container in which the label is fused to the surface of the plastic container. .
On the other hand, in the injection molding, the in-mold label is disposed in the cavity of the female mold so that the low melting point resin layer (B) side of the label faces the cavity side of the mold (contacts with the resin of the container material). After fixing to the inner wall of the mold by suction or static electricity, and clamping the mold, the resin melt as the container molding material is injected into the mold to form the container, and the mold is opened and the label is fused to the surface of the plastic container. The labeled container is molded.
In the differential pressure molding, the in-mold label is placed in the cavity of the lower female mold of the differential pressure mold, and the low melting point resin layer (B) side of the label is on the cavity side of the mold (so that it contacts the resin of the container material). After being placed so as to face, it is fixed to the inner wall of the mold by suction or static electricity. Next, a plastic container with a label in which a semi-molten resin sheet serving as a container molding material is guided to the upper part of the lower female mold, subjected to differential pressure molding by a conventional method, and the label is integrally fused to the outer wall of the plastic container. Molded. As the differential pressure forming, either vacuum forming or pressure forming can be adopted, but in general, differential pressure forming using both of them and utilizing plug assist is preferable.

[Characteristics of labeled containers]
As described above, a labeled container having an in-mold label adhered to the surface of the polar resin container is obtained. The labeled container preferably has the following characteristics.

(Adhesive strength)
The adhesive strength between the polar resin container and the in-mold label is measured in accordance with JIS K6854-2: 1999 “Adhesive—Peeling adhesive strength test method—Part 2: 180 degree peeling”. In the situation where no blisters (bubbles) are generated, the adhesive strength is preferably 2N / 15 mm or more, more preferably 4N / 15 mm or more, and further preferably 5N / 15 mm or more. On the other hand, the upper limit of the adhesive strength is not particularly limited, but is preferably 15 N / 15 mm or less from the cohesive fracture strength of the low melting point resin layer (B) resin.

(Waterproof peeling)
When a container with a label is immersed in warm water, the label does not easily peel off.However, if the label is designed to peel off naturally when immersed for a long time, the container can be recycled by peeling the label from the container with the label. improves. In this application example, an example in which the film does not peel even after being immersed in warm water at 25 ° C. for 10 hours is not limited to this, but the composition of the low melting point resin layer (B), the thickness of the low melting point resin layer (B), and the solubility parameter By appropriately setting conditions such as the type of surface activation treatment and the treatment amount, it is possible to impart peelability according to the cleaning conditions (composition of the cleaning liquid, liquid temperature, immersion state, etc.).

Hereinafter, the features of the present invention will be described more specifically with reference to examples and comparative examples.
The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Example 1>
Extrusion of a thermoplastic resin film (A) as a material for the thermoplastic resin film (A) heated at 230 ° C. with a thermoplastic resin composition having a PP-1 content of 84% by mass, a CA-1 content of 15% by mass, and a TI-1 content of 1% by mass. The mixture was melt kneaded with a machine and supplied to a two-layer die.
On the other hand, PE-1 shown in Table 1 as a material for the low melting point resin layer (B) was melt-kneaded with an extruder heated to 210 ° C. and supplied to a two-layer die.
In the two-layer die, the material of the thermoplastic resin film (A) and the material of the low melting point resin layer (B) were laminated and extruded from the T die as a two-layer film having two types of layers.
This was cooled by a cooling device to obtain an unstretched sheet having a two-layer structure. This unstretched sheet was heated to 150 ° C. and stretched 5 times in the longitudinal direction. Next, after cooling to a temperature of 60 ° C., it is again heated to a temperature of 150 ° C., stretched 8 times in the transverse direction with a tenter, annealed at a temperature of 160 ° C., cooled to a temperature of 60 ° C., A white opaque biaxially oriented polyolefin-based laminated resin film having a two-layer structure was obtained.
Next, this was guided to a corona discharge treatment device with a guide roll, subjected to corona discharge treatment at a treatment amount of 50 W / m ² on each of both surfaces, cut off the ears, and wound up with a winder.
The resulting white opaque biaxially stretched polyolefin-based laminated resin film having a two-layer structure had a thickness of 70 μm and a density of 0.76 g / cm ³ . The low melting point resin layer (B) had a thickness of 2.0 μm and a surface tension of 64 mN / m.
The white opaque biaxially stretched polyolefin-based laminated resin film having this two-layer structure was used as the in-mold label of Example 1.

<Example 2>
In Example 1, the composition of the thermoplastic resin composition for the thermoplastic resin film (A) was changed to that without inorganic fine filler as shown in Table 2 to obtain a colorless and transparent biaxially stretched polyolefin-based laminated resin film. This colorless and transparent biaxially stretched polyolefin-based laminated resin film was used as the in-mold label of Example 2.

<Example 3>
In Example 1, the composition of the thermoplastic resin composition for the thermoplastic resin film (A) was changed to PE-2 having a melting point of 90 ° C. described in Table 2 below, and a white opaque biaxially oriented polyolefin-based laminated resin A film was obtained. This white opaque biaxially oriented polyolefin-based laminated resin film was used as the in-mold label of Example 3.
By comparison of Example 3 and Example 1 in the adhesive strength test result described later, Example 1 using PE-1 having an ethylene copolymerization ratio of 95% or more has an ethylene copolymerization ratio of 95. It was shown that adhesive strength becomes higher than Example 3 using PE-2 which is less than%.

<Comparative Example 1>
An in-mold label of Comparative Example 1 was produced in the same manner as in Example 1 except that the corona discharge treatment was not performed in Example 1.
As a result of the adhesive strength test described later, when a labeled container was manufactured using the in-mold label of Comparative Example 1, sufficient adhesive strength was not obtained. The surface tension of the surface of the low melting point resin layer (B) was 32 mN / m, and the O / C ratio was 0.005. In the case where the low melting point resin layer (B) is a polyethylene resin, in order to attach the low melting point resin layer (B) to a polyethylene terephthalate container by in-mold molding using an in-mold label having the outermost layer, corona It was shown that the activation treatment represented by discharge is essential.

<Comparative example 2>
In Example 1, an in-mold label of Comparative Example 2 in which the thickness of the low melting point resin layer (B) was 0.8 μm was produced by narrowing the supply amount of the low melting point resin layer (B) to the two-layer die.
When the labeled container was manufactured using the in-mold label of the comparative example 2 as the test result of the adhesive strength mentioned later, it became low adhesive strength. From Comparative Example 2, the thickness required for obtaining the adhesive strength by filling the low melting point resin layer (B) between the label and the container was shown.

<Comparative Example 3>
In Example 1, the same procedure as in Example 1 was used except that PE-3 having a melting point of 115 ° C. was used for PE-1 having a melting point of 81 ° C. for the polyethylene resin used for the low melting point resin layer (B). Thus, an in-mold label of Comparative Example 3 was produced.
When the labeled container was manufactured using the in-mold label of the comparative example 3 as the test result of the adhesive strength mentioned later, it became low adhesive strength. In Comparative Example 3, in order for the low melting point resin layer (B) to fill the space between the label and the container, it is necessary for the low melting point resin layer (B) to melt, and the low melting point resin layer (B) melts. Indicates the critical point of peak temperature (melting point).

<Evaluation method>
[In-mold label properties]
(Thickness of each layer)
The thickness (total thickness) of the in-mold label was measured in accordance with JIS K7130: 1999 using a constant pressure thickness measuring instrument (trade name: PG-01J, manufactured by Teclock Co., Ltd.). The thickness of each layer in the in-mold label is determined by cooling the sample to be measured to a temperature of −60 ° C. or lower with liquid nitrogen and placing it on a glass plate with a razor blade (manufactured by Sick Japan Co., Ltd.). , Product name: Proline blade) was cut at right angles to prepare a sample for cross-sectional observation, and the obtained sample was used with a scanning electron microscope (manufactured by JEOL Ltd., product name: JSM-6490). Cross-sectional observation was performed, the boundary line for each thermoplastic resin composition was determined from the appearance, and the total thickness of the in-mold label was multiplied by the observed layer thickness ratio.

(Surface atomic composition ratio O / C value)
Using an X-ray photoelectron spectrometer (K-Alpha manufactured by Thermo Fisher Scientific), the active treatment surface of the surface of the low melting point resin layer (B) is excited X-ray: Al Kα ray, and the photoelectron escape angle is 90 degrees. The bond energy value of the C1s main peak was 284.6 eV, and the energy of the 1s orbit was measured. From the obtained spectrum, the area ratio of the C1s peak to the O1s peak (the number of oxygen atoms / the number of carbon atoms), (O / C value).

(surface tension)
In accordance with JIS K6768: 1999, when a wetting tension test mixture (manufactured by Wako Pure Chemical Industries, Ltd.) is applied to the measurement surface of the low melting point resin layer (B), the low melting point resin layer (B) (film) is wetted. The surface tension of the standard solution having the lowest surface tension determined was defined as the surface tension of the measurement surface. The unit was expressed in mN / m.

(Corona discharge treatment trace)
Powder toner (model number: TK-571M, manufactured by Kyocera Mita, plus charge type) and glass beads with a particle diameter of 2.5 mm are placed in a PP screw bottle (50 ml), and the bottle is shaken by hand for 3 minutes to aggregate. Was crushed. The obtained toner was sprinkled on the surface of the low melting point resin layer (B) of the in-mold label, and the presence or absence of a corona discharge treatment trace was visually confirmed and judged according to the following criteria.
Existence: Toner adheres to the surface of the low melting point resin layer (B) of the in-mold label, and the pattern appears to float.
No: No toner adheres to the surface of the low melting point resin layer (B) of the in-mold label. Alternatively, the toner adheres to the surface of the low melting point resin layer (B) of the in-mold label, but the pattern does not appear.

[Characteristics of labeled containers]
(Manufacture of labeled containers)
The in-mold labels obtained in each example and each comparative example were punched into a rectangle having a long side of 8 cm and a short side of 6 cm.
Next, the punched in-mold label was charged using an electrostatic charging device. Subsequently, inside the molding die of a stretch blow molding machine (manufactured by Nissei ASB Co., Ltd., trade name: ASB-70DPH) so that the opposite surface of the low melting point resin layer (B) is in contact with the die (the seal layer is a cavity) Installed and clamped. The in-mold label was installed so that the long side of the label was adhered in parallel to the circumferential direction of the body of the resin molded body in the mold. The mold was controlled so that the surface temperature on the cavity side was in the range of 20 to 45 ° C.
Meanwhile, a polyethylene terephthalate preform was preheated to 100 ° C. Next, the reform was guided to a mold, and stretch blow-molded for 1 second under a blow pressure of 5 to 40 kg / cm ² . Then, it cooled to 50 degreeC in 15 seconds.
Next, the mold was opened, and the labeled container having a square body having a height of 12 cm and a side of about 7 cm was taken out.

(In-mold label adhesive strength)
The labeled container to be measured was stored for 2 days in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Next, the container wall and the label of the label sticking part are cut together with a cutter, and the length of the circumferential direction of the container body is 12 cm (the sticking part of the label is 9 cm, the non-sticking part is 3 cm) and A total of 6 samples for measurement having a width of 1.5 cm (with labels attached to the entire width) were collected from two containers.
Next, the label was carefully peeled off from the gripping (unlabeled) part and peeled about 1 cm to form an adhesive part for gripping. Next, the end of a 1.5 cm wide PET film (50 μm) and the above-mentioned adhesive portion were overlapped and adhered with an adhesive to form a gripping portion on the label side, thereby preparing a sample for measuring adhesive strength.
Next, based on JIS K6854-2: 1999, the 180 degree | times peeling test was implemented on the conditions of peeling speed 300mm / min using the tensile tester (Shimadzu Corporation autograph AGS-5kNJ). The average value of the peeling force between the peeling lengths of 25 mm to 75 mm was measured, and the value obtained by averaging the measured values of 6 samples was taken as the adhesive strength. The unit of adhesive strength was N / 15 mm.
In addition, about the molded article with a label of the comparative example 1, since most parts of the label floated from the container and peeled off at the time of sampling and could not be measured stably, it was determined that the comparative example 1 was “not adhered”.

(Water peeling test)
The container with a label to be measured was immersed in warm water at 25 ° C. for 3 hours or 10 hours, and a peel test was performed in water. If the label can be slid with a finger, “peel” is assumed.
A: It does not peel off by immersion for 10 hours.
B: Not peeled after 3 hours immersion, but peeled after 10 hours immersion.
C: Peel off by immersion for 3 hours.

[Others]
The material MFR (melt flow rate according to JIS K7210: 1999), melting point (melting peak temperature according to JIS K7121: 1987), ethylene content, density, and volume average particle diameter of inorganic fine powders were used as catalog values for each material. .

<Example 101>
“Epomin SP-003” manufactured by Nippon Shokubai Co., Ltd. and “Saftmer ST-1000” manufactured by Mitsubishi Chemical Co., Ltd. were mixed to prepare a coating material for an ink receiving layer (C) having a solid content concentration of 3 mass%.
The paint is applied to the thermoplastic resin film (A) side of the white opaque biaxially stretched polyolefin-based laminated resin film having a two-layer structure prepared in Example 1 with a Mayer bar # 8 and dried at 80 ° C. for 45 seconds. An ink receiving layer (C) was provided.
Next, printing is performed on the surface of the ink receiving layer (C) using a flexographic printing machine (manufactured by MT Tech Co., Ltd., device name: FC11B) using UV flexographic ink (manufactured by T & K TOKA, product name: flexo 500). Then, an in-mold label on which a pattern was printed was produced and used as the in-mold label of Example 101.
A labeled container was produced in the same manner as in Example 1 except that the in-mold label of Example 101 was used. As a result, an adhesive strength was developed in the same manner as in Example 1, and a labeled container having a pattern was obtained.

  According to the in-mold label of the present invention, it becomes possible to adhere to polyester using a film having a polyethylene resin as an adhesive layer that cannot be adhered to polyester with conventional common sense, and even a low-temperature adhesive condition by stretch blow molding can be a molded product. A molded article having sufficient adhesive strength can be obtained. Therefore, it becomes possible to manufacture an in-mold label for both polyester containers / polyolefin containers, which greatly contributes to cost reduction in the field.

Claims (7)

Having a low melting point resin layer (B) on one surface of the thermoplastic resin film (A),
The low melting point resin layer (B) contains a polyethylene resin,
The melting point of the polyethylene resin is 60 to 110 ° C.,
The low melting point resin layer (B) has a thickness of 1.5 to 15 μm,
An in-mold label, wherein the surface of the low melting point resin layer (B) is activated.   The in-mold label according to claim 1, wherein the polyethylene resin is a copolymer of 95 mol% or more and less than 100 mol% of ethylene and more than 0 mol% and 5 mol% or less of a monomer copolymerizable with ethylene.   The in-mold label according to claim 1, wherein a corona discharge treatment trace is present on the surface of the low melting point resin layer (B).   The in-mold label according to any one of claims 1 to 3, wherein a surface tension of the surface of the low melting point resin layer (B) is 45 to 75 mN / m.   The in-mold label according to any one of claims 1 to 4, wherein the thermoplastic resin film (A) has an ink receiving layer (C) on a surface not having the low melting point resin layer (B).   A labeled container in which the in-mold label according to any one of claims 1 to 5 is attached to a surface of a polar resin container.   The labeled container according to claim 6, wherein the polar resin is a polyester resin.