JP2005037624A - Label for in-mold molding and in-mold label molded container using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a label for in-mold molding which does not use aluminum foil and aluminum vapor deposited film, permits inspection with a metal finder or the like, is good in appearance as both surfaces of the container are not visible blackish, is excellent in light shieldability of UV light and visible light, and in suitability for preservation of contents, prevents the occurrence of an orange peel, is prevented of generation of static electricity between the labels with each other, prevents the occurrence of two-sheet feeding during label supplying, is excellent in the workability for forming the same and is inexpensive and the in-mold label molded container using the same. <P>SOLUTION: The in-mold label which is inserted into a metal mold and is fused to the container simultaneously with molding at the time of molding the container is formed by successively laminating synthetic paper 2 composed of a stretched resin film which is a base material layer, a brown solid printing layer 4 which is a light shielding layer to shield the visible light and UV light and a heat sealing layer 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-mold molding label and an in-mold label molding container using the same, and more specifically, without using an aluminum foil or an aluminum vapor deposition film, it is possible to inspect a metal detector, etc. Excellent storage stability and antistatic properties of the contents, prevents both sides of the container from appearing dark, prevents orange peel, prevents double feeding during label supply, and excels in molding workability. The present invention relates to an inexpensive label for in-mold molding and an in-mold label molding container using the label.
[0002]
[Prior art]
Conventionally, an in-mold labeling molding method is known as one of surface decoration techniques for plastic molded products. This is a molding method in which the label is attached to the surface of the molded product in the mold at the same time as plastic molding. For example, decorations made up of letters, figures, symbols, patterns, etc. can be easily applied to the surface of the molded product. Since it can be applied to injection molding, blow molding, thermoforming molding and the like, its needs are increasing in recent years. More specifically, the above-described in-mold labeling molding method will be described in detail. For example, in the case of the in-mold labeling molding method for injection molding, a label that has been printed and cut in advance is prepared. Is supplied to the label feed section provided in the system and supplied into the mold for each shot, or the label is manufactured while being printed in advance with a label cutting machine or the like. At the same time, the label is supplied into the mold by a method of supplying it into the mold every shot, and then the molten injection molding resin is supplied into the mold equipped with the label to label the surface of the molded product. At the same time, injection molding is performed to perform in-mold labeling molding.
The molded product molded by the above-described in-mold labeling molding method has a beautiful surface decoration pattern such as letters, figures, symbols, and patterns on its surface, and is extremely rich in quality. , Juice, milk, yogurt, ice cream, butter, margarine, etc., are used in various fields as molded containers for filling and packaging various foods and beverages.
Further, in order to use as a molded container for filling and packaging the above various foods and drinks, the container itself does not block ultraviolet light with a light wavelength of 380 nm or less and visible and near infrared light with a light wavelength of 380 to 550 nm. In the case of a molded product of material, it is necessary to cover the container with a label having a light shielding property (light shielding property) in order to preserve the contents for a long period of time.
As such a composite container with excellent light concealing property, for example, on the inner surface of a blank inserted into a mold, a thermoplastic resin is injection molded to form a container, or on the inner surface of a blank inserted into a mold. In a composite container having a structure in which a blank (in-mold label) is integrally heat-sealed to a container obtained by molding a thermoplastic synthetic resin composite sheet heated using compressed air and / or vacuum into the container. The (in-mold label) is provided with a light shielding layer on the back surface of a synthetic paper made of a stretched resin film having an opacity of 85% or more, a porosity of 10 to 60%, and a thickness of 30 to 500 μm. A composite synthetic paper of 100% opacity with a heat-sensitive resin adhesive layer provided on the back side of the paper, and a light (printed on the surface of the synthetic paper layer) that is a blank (in-mold label) Excellent composite container 蔽性 is disclosed (for example, see Patent Document 1.).
In addition, as a composite container having excellent light hiding properties, a label in which a light shielding layer made of an aluminum-deposited biaxially stretched plastic film is laminated on the back surface of the substrate, or a light shielding layer made of a black solid printing layer on the back surface of the substrate layer However, a label-attached container having a light-shielding property, characterized in that it is attached to the outer periphery of the peripheral wall portion of the container body (see, for example, Patent Document 2).
[0003]
[Patent Document 1]
JP-A-7-232723 [Patent Document 2]
JP-A-8-230953 [0004]
[Problems to be solved by the invention]
However, in the composite containers of Patent Documents 1 and 2, in the labeled composite container provided with a black solid print layer as a blank light-shielding layer, the consumer looks at the inside of the container as blackened, and the consumer can eat and drink in the container. When you take in, the color of the inside of the container can be seen, or the contents of food and drink can be seen darkened, so the appetite is reduced, and the outside of the container looks dark, so the printed pattern on the surface does not look good Therefore, there is a drawback that the commercial value is significantly impaired.
Further, if the color inside the container body is white, the transmission of ultraviolet light can be prevented, but the light in the visible part cannot be completely prevented, and the contents are deteriorated.
In addition, in the labeled container of Patent Document 2, when it is used as a packaging container and then disposed of as garbage, for example, if it is disposed of by incineration or the like, metal such as aluminum may remain and damage the incinerator. In addition, there is a problem that it is not suitable for disposal and causes problems such as environmental destruction, and also lacks environmental suitability, etc.Furthermore, metal foils such as aluminum foil are heavy and are used for containers and packaging. There is also a problem of lack of weight reduction.
Moreover, since aluminum foil lacks bending resistance and the like in the process of physical distribution, there is a problem that pinholes are generated and the light shielding property thereof is significantly impaired.
In addition, since the pattern printing on the front side of the container main body has a poor appearance of the pattern printing due to the inner aluminum vapor deposition film, there is a disadvantage that the commercial value is remarkably impaired.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have intensively researched and found that the present invention is an in-mold label that is inserted into a mold at the time of molding a container and welded to the container at the same time as molding. A label for in-mold molding characterized by sequentially stacking a synthetic paper made of a stretched resin film as a material layer, a brown solid print layer as a light shielding layer that blocks visible light and ultraviolet light, and a heat seal layer When the label is molded with in-mold labeling, it can be inspected with a metal detector, etc. without using aluminum foil or an aluminum vapor-deposited film. The printed pattern of this product has a good appearance, has excellent ultraviolet and visible light shielding properties, excellent storage stability of the contents, prevents the occurrence of orange peel, has an excellent appearance, and is inexpensive for in-mold molding. Inmo using it - Rudoraberu is obtained by finding molded container and completed the present invention.
In addition, by providing an in-mold forming label characterized by providing an antistatic layer on the front or back surface of the base material layer, it is excellent in antistatic and prevents the occurrence of two-sheet insertion during label supply. The molding workability is excellent.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The above-described present invention will be described in more detail below with reference to the drawings. First, FIG. 1 and FIG. 2 are schematic sectional views showing the layer structure of the in-mold molding label according to the present invention, and FIG. 3 is the in-mold labeling according to the present invention shown in FIG. 1 or FIG. It is a schematic explanatory drawing explaining an example which uses a label for manufacture and manufactures a molded article by in-mold labeling molding.
FIG. 1 shows the layer structure of an in-mold label 1 according to the present invention.
The in-mold label 1 has a pattern printing layer 3 formed on the surface of the base material layer 2 made of synthetic paper and a light shielding layer 4 made of a brown solid printing layer on the back surface of the base material layer 2. The heat seal layer 5 made of a thermoplastic resin is laminated on the light shielding layer 4 side of the base material layer 2.
Further, a glossy OP (overprint) varnish layer 6 may be formed on the surface of the pattern side print printing layer 3.
[0007]
FIG. 2 shows a layer configuration of another embodiment of the in-mold label 1 according to the present invention.
The in-mold label 1 has a pattern printing layer 3 formed on the surface of the base material layer 2 made of synthetic paper and a brown color on the back surface of the base material layer 2 via the antistatic layer 7. A light shielding layer 4 made of a solid printing layer is formed, and a heat seal layer 5 made of a thermoplastic resin is laminated on the light shielding layer 4 side of the base material layer 2.
Moreover, you may provide said antistatic layer 7 not in the interlayer of a base material layer and a brown printing layer but in the outer surface side of a base material layer.
Further, a glossy OP (overprint) varnish layer 6 may be formed on the surface of the pattern side print printing layer 3.
[0008]
Next, in the present invention, the materials constituting the in-mold molding label 1 according to the present invention as described above, the manufacturing method thereof, and the like will be described. First, the synthesis constituting the in-mold molding label 1 according to the present invention. The paper (base material layer) 2 is a synthetic paper made of a stretched resin film whose main component is a thermoplastic resin having a large number of fine pores.
Examples of the thermoplastic resin material constituting the synthetic paper include various polyethylene resins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear (linear) low-density polyethylene, and others, and polypropylene resins. , Polystyrene resins, polyacrylonitrile resins, poly (meth) acrylic resins, polyester resins, polyamide resins, polyaramid resins, polycarbonate resins, polyacetal resins, etc. The following film or film can be used. Furthermore, in the present invention, a co-extruded film obtained by co-extrusion molding by arbitrarily combining the above resins can also be used.
As the resin film as described above, a stretched film or sheet stretched in a uniaxial or biaxial direction can be used, and the stretch ratio is preferably 4 to 10 times, and the thickness is 6 μm to 100 μm. From the viewpoint of tensile strength and bending strength, it is desirable to use one having a thickness within the range of 20 μm to 60 μm.
[0009]
The above synthetic paper (base layer) 2, an opacity (JIS P-8138), less than 50% 85%, ^density, to be in the range of ^{0.80g / cm 3 ~0.95g / cm 3} , ultraviolet If a label using this is used, the preservability of the contents is improved, orange peel is unlikely to occur, and the appearance of the container is preferable.
In addition to synthetic paper, paper, synthetic resin-impregnated paper, synthetic resin-coated paper, and the like can be suitably used.
[0010]
The thermoplastic resin can be used by containing an inorganic fine powder or an organic fine powder. As the inorganic fine powder, for example, calcium carbonate, calcined clay, silica, diatomaceous earth, talc, titanium oxide, barium sulfate and the like can be used, and as the organic fine powder, for example, polyester resin, polycarbonate, polystyrene and the like can be used. .
[0011]
In the present invention, as the pattern printing layer 3 formed on the in-mold molding label, for example, a normal gravure ink composition, an offset ink composition, a screen ink composition, or the like is used, and gravure printing is performed. For example, an arbitrary printing pattern such as a character, a figure, a symbol, a pattern, or the like can be printed and formed using a method, an offset printing method, a screen printing method, a transfer printing method, or the like. Thus, such a print layer can be formed on both the front and back surfaces of the front substrate layer, or one of the surfaces.
[0012]
As the printing ink constituting the brown solid print layer 4 imparting light-shielding properties according to the present invention, for example, a binder resin is a main component of the vehicle, and a colorant such as a dye / pigment is added thereto. A coloring ink composition obtained by arbitrarily adding an auxiliary agent and sufficiently kneading with a solvent / diluent or the like can be used.
In the above, examples of the binder resin include polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, polyacrylic or methacrylic resin, maleic acid resin, fumaric acid resin, and polyacrylic resin. Nitrile resin, polyolefin resin, acid-modified polyolefin resin, polystyrene resin, drying oil alkyd resin, alkyd resin, polyester resin, polyamide resin, polyurethane resin, phenol resin, amino resin, epoxy A mixture of one or more of a resin, a rosin resin, a fiber resin such as ester gum, nitrocellulose or ethyl cellulose, a rubber derivative, a petroleum resin, and the like can be used.
In the above, examples of colorants such as dyes and pigments include yellow pigments such as fast yellow, disazo yellow, titanium yellow, yellow iron oxide, and yellow lead, toluidine red, lake red, Red, orange or brown pigments such as Bengala, molybdenum red, vermilion, blue or green pigments such as ultramarine, bitumen, cobalt titanium green, chromium oxide, titanium oxide, zinc white, zinc sulfide, etc. White pigments, black pigments such as carbon black, extender pigments such as calcium carbonate, precipitated barium sulfate, clay, talc, azo dyes / pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments 1 type or colorant such as pigment, dioxazine pigment, thioindigo pigment, anthraquinone dye / pigment, and other dyes / pigments It is possible to use mixtures of the above.
Furthermore, in the above, examples of the auxiliary agent include auxiliary agents such as stabilizers, plasticizers, ultraviolet absorbers, antioxidants, lubricants, antistatic agents, fillers, waxes, greases, dispersants, and the like. One or more agents can be optionally added and used. In the above, examples of the solvent / diluent include alcohol solvents, ester solvents, ether alcohol solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, ketone solvents. Others can be used.
In the present invention, the above materials are used, for example, premixing is performed using a mixer, a kneader or the like, and then a roll mill, a ball mill, a sand mill, or the like is used. A printing ink can be produced by kneading.
[0013]
Next, in the present invention, as a method of forming the brown solid print layer 4, for example, the above-described printing ink is used, and on the base film layer or the like, offset printing, silk screen printing, It can be formed by a coating method such as gravure printing, flexographic printing, transfer printing, roll coating, knife coating, spray coating, or the like.
The film thickness is preferably within the range of 0.5 g / m ² or more and 3 g / m ² or less of the brown ink layer 4 applied (dry state).
When the coating amount (dried state) of the brown ink layer 4 is less than 0.5 g / m ² , the light shielding function is inferior, and it is not preferable because it cannot be applied uniformly, and even if it exceeds 3 g / m ² The total light transmittance is not improved and is not preferable from the viewpoint of cost performance.
[0014]
The solid print layer 4 imparting light-shielding properties can be composed of a single-layer print layer, but can also be formed by overprint printing of two or more layers.
In the present invention, the solid print layer 4 imparting light-shielding properties is composed of a sepia-tone brown printing ink, for example, a mixed color composed of magenta, yellow, and black inks. Other colors such as cyan and white ink may be mixed.
For example, in the present invention, the brown mixed ink 4 includes magenta ink and yellow ink pigment added (dry state), 5 wt% to 20 wt%, and black ink pigment 10 wt% to 40 wt%. What contains in the range of weight% is preferable.
By making the addition amount of the pigment within the above range, the total light transmittance of the brown solid print layer 4 can be suppressed to 0.3% or less, and it has excellent light shielding properties and can prevent deterioration of the contents. It is preferable.
On the other hand, when the amount of the pigment is less than the above-described addition amount, the light-shielding property is insufficient, and when the above-mentioned addition amount is exceeded, the print transfer rate is lowered and the printability is inferior.
[0015]
Moreover, in this invention, as a material which forms the heat seal layer 5 which comprises the label for in-mold shaping | molding concerning this invention, as a high density polyethylene, a medium density polyethylene, a low density polyethylene, a linear form, for example Low density polyethylene, ethylene / propylene copolymer, polypropylene resin, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer resin, blend of ethylene / vinyl acetate copolymer and chlorinated polypropylene resin, ethylene / isobutyl acrylate Copolymer resin, vinyl alcohol, polyamide resin, polyester resin, butyral resin, polyvinyl acetate and its copolymer resin, cellulose derivative, polymethyl methacrylate resin, polyvinyl ether resin, polyurethane resin, polycarbonate resin, epoxy resin, phenol It consists ethylene (meth) coating layer of a thermoplastic resin ionomer such as metal salts of acrylic acid copolymers such as a resin, the thickness, coating ^{weight, 1g / m 2 ~20g / m} 2 about preferably it is more preferable to form about ^{3g / m 2 ~10g / m 2} .
[0016]
Further, the antistatic layer 7 in the present invention is provided with irregularities between the base material layer and the brown solid print layer with a resin coating material having a thickness of about 0.5 μm to 6 μm to form an air layer. By providing it, antistatic properties are imparted.
The in-mold label according to the present invention is advantageous in that by providing an antistatic layer on the front surface or the back surface of the base material layer, generation of static electricity between the labels is prevented, and the label supply property at the time of in-molding is improved. Have
[0017]
Next, in the present invention, as the barrier layer forming the functional layer constituting the label for in-mold labeling, for example, a material having a property of not transmitting water vapor, water, oxygen gas or the like may be used. This may be a single substrate or a composite substrate formed by combining two or more substrates. Specifically, for example, a film such as a polyester resin having a vapor-deposited film of an inorganic oxide such as silicon oxide or aluminum oxide having a barrier property can be used.
The thickness of the above film or sheet is arbitrary, but usually about 6 μm to 100 μm can be used. Further, in the above, a deposited film of inorganic oxide having a thickness of about 100 to 2000 mm can be used.
[0018]
In the present invention, as an example of the molding method for in-mold labeling molding using the above-described in-mold molding label, the in-mold labeling molding method is as shown in FIG. An injection mold S including a core mold 11, a cavity mold 12, a runner 13, a gate port 14, vacuum suction devices 15a and 15b attached to the cavity mold 12 is used. The vacuum forming device 15a is applied to the inner wall surface of the cavity-mold 12 so that the above-mentioned label 1 for forming an mold according to the present invention is tightly bonded to a position corresponding to the entire surface of the outer wall surface of the body of the molding container. , 15b, etc., are attached while being fixed by vacuum suction, and then the core mold 11 is fixed to the cavity mold 12, and then the cavity mold 12 and the core mold 1 are fixed. In a space formed by the above, a molten cylinder 16 (for example, a polyethylene-based resin additive-free additive) is passed through a runner 13 by a heating cylinder (not shown) to a gate port 14. The molded label 17 conforming to the shape of the space is molded and the label 1 for in-mold labeling is integrated and tightly bonded to the entire outer wall surface of the trunk portion constituting the molded container 17, Thereafter, the molded container 17 is taken out by cooling and solidification, and an in-mold label forming container using the in-label labeling label 1 according to the present invention can be manufactured. The above illustration is an example of the molding method, and is not limited to this. For example, although not shown, the label 1 is integrated on the entire outer wall surface of the trunk as described above. In addition to tightly bonding, the label 1 can be integrated and tightly bonded to the entire outer wall surface of the bottom, and as described above, the label 1 can be integrated to the entire outer wall surface of the body portion. The label 1 can be integrated and tightly bonded to the entire inner wall surface at the bottom of the bottom.
[0019]
Examples of the molding resin used in the above in-mold labeling molding method include polyethylene such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear (linear) low-density polyethylene, and ethylene-propylene copolymer. Various molding resins such as resin, polypropylene resin, polystyrene resin, polyester resin, polyamide resin, polycarbonate resin, polyacrylonitrile resin, (meth) acrylic resin, etc. be able to.
The in-mold label 1 is inserted into a mold at the time of molding a container made of polypropylene (PP), impact-resistant polystyrene (HIPS) or the like, and attached to the container at the same time as injection molding.
[0020]
【Example】
Next, the present invention will be described in more detail with reference to examples.
(Example 1)
A predetermined printing pattern is printed on one surface of a synthetic paper having a thickness of 80 μm, a density of 0.85 g / m ² to form a printing layer, and then a pattern printing layer of the synthetic paper is not formed. On the other side, a silica-based resin having a thickness of 3 μm (dried state) was coated as an antistatic layer, and further, 18.8% by weight of magenta ink (pigment in the dry state) 8.4% by weight), yellow ink 35.6% by weight (pigment 11.1% by weight), black ink 45.6% by weight (pigment 21.7% by weight) mixed ink The brown solid print layer 4 made of was subjected to gravure printing to form a light shielding layer having a coating amount of 1 g / m ² (dry state).
[0021]
Mixing ratio of magenta ink / binder (urethane resin) / solvent, 10.0 / 11.5 / 78.5
Mixing ratio of yellow ink / binder (urethane resin) / solvent, 6.9 / 13.0 / 80.1
Mixing ratio of black ink / binder (urethane resin) / solvent, 10.7 / 14.1 / 75.2
[0022]
Furthermore, a heat seal material composed of a blend of an ethylene-vinyl acetate copolymer and a chlorinated polypropylene resin is coated at a coating amount of 2.5 g / m ² (dry state) to form a heat seal layer. A label-forming laminate was produced.
Using the above-mentioned laminated material for forming a label, a side label to be closely adhered to the entire outer wall surface of a molded container having a predetermined size was punched out.
Next, a vacuum suction device or the like is used on the inner wall surface of the cavity-mold so that the biaxially stretched polypropylene film surface having the heat sealing property is in contact with the molding resin. Then, it was mounted while being sucked and fixed. Next, the core mold is fixed to the cavity mold, and then the additive-free high-density polyethylene melted by the heating cylinder is melted in the space formed by the cavity mold and the core mold. Resin is injected from the gate opening through the runner to form a container that matches the shape of the space of the above mold, and the label is melted and integrated on the outer wall surface of the body part that constitutes the container to be tightly bonded. Thereafter, it was cooled and solidified, and the molded product was taken out to produce an in-mold molded container.
In the above, the label was not curled, there was no blocking phenomenon, and it could be satisfactorily supplied into the molding die for each shot, and in-mold molding could be performed satisfactorily.
In addition, the packaging container described above can be inspected by a metal detector, etc. without using aluminum foil or aluminum vapor-deposited film, looks good because both sides of the container do not appear dark, no orange peel occurs, It was excellent in ultraviolet and visible light shielding properties and storage suitability for contents.
[0023]
【The invention's effect】
As apparent from the above description, the present invention is an in-mold label that is inserted into a mold at the time of container molding and welded to the container at the same time as molding, and a synthetic paper made of a stretched resin film as a base material layer; Producing an in-mold molding label characterized by sequentially laminating a brown solid printing layer, which is a light shielding layer that blocks visible light and ultraviolet light, and a heat seal layer, and the label is, for example, for injection molding It is supplied to the label feed section provided in the system related to the in-mold labeling molding method, supplied to the mold every shot, and subjected to in-mold labeling molding. Can be used to inspect metal detectors, etc., and both sides of the container do not look black, it looks good, it has excellent UV and visible light shielding properties, and the contents are well preserved. To prevent the occurrence of Le, inexpensive Inmo - is that it can be manufactured Rudoraberu molded container - field forming labels and Inmo using it.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing the layer structure of an in-mold label according to the present invention.
FIG. 2 is another schematic cross-sectional view showing the layer structure of the in-mold molding label according to the present invention.
FIG. 3 is a schematic explanatory view for explaining an example in which a molded product is manufactured by in-mold labeling using the in-mold forming label according to the present invention shown in FIG. 1 or FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 In-mold label 2 Base material layer 3 Picture printing layer 4 Brown solid printing layer (light-shielding layer)
5 Heat Seal Layer 6 OP (Overprint) Varnish Layer 7 Antistatic Layer 11 Core Mold 12 Cavity-Mold 13 Runner
14 Gate ports 15a and 15b Vacuum suction device 16 Molding resin 17 Molding container S Injection mold

Claims (3)

An in-mold label that is inserted into a mold at the time of container molding and welded to the container at the same time as molding, and is a synthetic paper made of a stretched resin film that is a base material layer and a brown that is a light shielding layer that blocks visible light and ultraviolet light A solid printing layer and a heat seal layer are sequentially laminated. The in-mold molding label according to claim 1, wherein an antistatic layer is provided on the front surface or the back surface of the base material layer. An in-mold label molding comprising: the in-mold label according to any one of claims 1 and 2 being closely bonded to an outer wall surface of a body portion of a thermoplastic resin molded container obtained by in-mold labeling. container.

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