JP2011002479A - Concealing label and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concealing label 10 which is manufactured in a few production steps and at low cost, and facilitates sticking to a material to be concealed so as to make a content and information invisible, however, can not be stuck again when the label is peeled off after having been used once, and also is superior in security, and to provide a method of manufacturing the same.SOLUTION: The concealing label is formed by laminating: a concealing layer 23 composed of a polyolefin-based resin including a filler and/or a coloring agent; a transparent layer 11 composed of an acrylic resin; an adhesive layer 19 composed of an acrylic adhesive resin; and a release layer 21 composed of a polyolefin-based resin, in this order, wherein the concealing layer 23, the transparent layer 11, the adhesive layer 19, and the release layer 21 are manufactured by a multilayer co-extrusion method.

Description

  The present invention relates to a concealment label used to conceal content information such as postcards. More specifically, the concealment label can be manufactured at a low cost with a small number of manufacturing processes. However, the present invention relates to a concealment label that cannot be attached again when it is peeled off after being used once, and a method for manufacturing the same.

  In the present specification, “ratio”, “part”, “%” and the like indicating the composition are based on mass unless otherwise specified, and the “/” mark indicates that they are integrally laminated. Also, “PET” is “polyethylene terephthalate”, “PEN” is “polyethylene-2,6-tephthalate”, “PVB” is “polyvinyl butyral”, “EVA” is “polyvinyl acetate” abbreviation, functional expression, common name Or an industry term.

(Background Art) With the enforcement of the Personal Information Protection Law, the handling of personal information and the protection of privacy are becoming increasingly important issues. For example, insurance and utility bill withdrawal notices were previously sealed letters, but it is common to use cheap postcards. Further, it is necessary to conceal and send the credit card or prepaid card number so that it cannot be seen by a third party until it reaches the person's hand. Alternatively, the information on winning or losing lotteries is known in advance and has no meaning for the lottery and needs to be concealed. In order to conceal such contents, for example, concealment labels are used.
Therefore, the concealment label can be manufactured at a low cost with few manufacturing processes, and it can be easily pasted to the concealed material to make the contents and information invisible. It is not possible to do this, and there is a need for security.

Japanese Utility Model Publication No. 3-108469

(Conventional technology) Conventionally, as a concealment label, for example, a peeling coat is applied to the aluminum foil side of a concealment layer in which paper and aluminum foil are laminated, and a plastic film is bonded with a hot press, and then an adhesive is applied to the plastic film side. A structure in which a release layer is sequentially laminated is known. However, in order to produce the label, there are a process of laminating paper and aluminum, a process of coating a release agent, a heat pressing process of laminating a plastic film, an adhesive coating process of providing an adhesive layer, and an extremely complicated process. There is a disadvantage that it is necessary and the manufacturing cost becomes high.
In addition, as a concealing label sheet material, a concealing layer in which a metal powder is blended with a flexible resin is formed on a transparent resin film in a temporary attachment state, and a base paper is pasted on the upper surface via an adhesive layer In addition, it is known that a release paper is detachably attached to the lower surface of the transparent resin film via a transparent adhesive (see, for example, Patent Document 1). However, the production of the label has the disadvantages that many complicated processes are required and the production cost increases.

  In order to solve the above-described problems, the present inventors have made extensive studies and have completed the present invention. Its purpose is that it can be manufactured at low cost with few manufacturing processes, and it can be easily attached to the concealed material to make the contents and information invisible, but if it is peeled off after use once, it should be attached again. It is an object of the present invention to provide a concealment label that cannot be used and has excellent security, and a method for manufacturing the same.

In order to solve the above problems, a concealment label according to the invention of claim 1 of the present invention is a concealment layer made of a polyolefin resin containing a filler and / or a colorant, a transparent layer made of an acrylic resin, an acrylic type An adhesive layer made of an adhesive resin and a release layer made of a polyolefin-based resin are laminated in this order.
According to a second aspect of the present invention, there is provided a concealing label according to the present invention, wherein the acrylic adhesive resin of the adhesive layer has the formula A-B-A (wherein A and B represent different polymer blocks, and A is an alkyl methacrylate ester). A methacrylic acid alkyl ester unit and an acrylic polymer in which the polymer blocks A and B have an alkyl group having 1 to 4 carbon atoms. This is mainly composed of acid alkyl ester units.
The concealment label according to the invention of claim 3 is such that the polymer block A is a methyl methacrylate polymer block and the polymer block B is a butyl acrylate polymer block.
The concealing label according to the invention of claim 4 is such that the polyolefin resin of the release layer is polyethylene and / or polypropylene.
The manufacturing method of the concealment label concerning invention of Claim 5 is a manufacturing method of the concealment label in any one of Claims 1-4, Comprising: The said concealment layer, the said transparent layer, the said adhesion layer, and the said peeling layer Is produced by a multilayer coextrusion method.

According to the first aspect of the present invention, it can be manufactured at a low cost with a small number of manufacturing processes, and it can be easily pasted and adhered to the material to be concealed, making the contents and information invisible, but when the concealing layer is peeled off In this case, it cannot be attached again and has an excellent security effect.
According to the second to third aspects of the present invention, in addition to the effect of the first aspect, there is an effect that can be more stably attached to the object to be concealed.
According to the fourth aspect of the present invention, in addition to the effects of the first to third aspects, it can be manufactured at a lower cost, and the release layer is peeled off in advance when the release layer is peeled off in advance when it is attached to a protected body. The film is not stretched or cut, and an effect of facilitating the peeling work is also achieved.
According to the present invention of claim 5, the concealment label having the effects of claims 1 to 4 can be manufactured in one process and the minimum manufacturing process, and an effect that can be manufactured at low cost is achieved.

It is sectional drawing of the concealment label which shows one Example of this invention. It is sectional drawing which shows the state which affixed the concealment label of this invention on the to-be-concealed material.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (Concealment Label) As shown in FIG. 1, the concealment label 10 of the present invention comprises four layers of a concealment layer 23, a transparent layer 11, an adhesive layer 19, and a release layer 21, and the concealment layer 23 is filled and / or colored. The transparent layer 11 is made of an acrylic resin, the adhesive layer 19 is made of an acrylic adhesive resin, and the release layer 21 is made of a polyolefin resin. At the time of use, the peeling layer 21 of the hiding label 10 is peeled off and removed, and the exposed adhesive layer 19 surface is bonded to the hiding material, so that the structure shown in FIG. The concealment information 103 is concealed. Moreover, the manufacturing method of the concealment label 10 of this invention can be shape | molded by one coextrusion method, for example by using a T-die coextrusion machine and an inflation coextrusion machine.

  (Transparent layer) As a material for forming the transparent layer, an acrylic resin is used from the viewpoint of transparency and weather resistance while maintaining the interlayer adhesive strength with the adhesive layer 19. For example, an acrylic resin mainly composed of a structural unit derived from a methacrylic acid ester and having a structural unit derived from an acrylate ester and / or another unsaturated monomer as needed is preferably used. Here, examples of the methacrylic acid ester include alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and pentyl methacrylate. Examples of the acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and pentyl acrylate.

  Although the thickness of the transparent layer 11 will not be specifically limited if it is the range which can identify concealment information after peeling the concealment layer 23, It exists in the range of 5 micrometers-200 micrometers. When the thickness is less than 5 μm, there is a risk that the concealment information may be poorly protected.

  (Adhesive layer) As a material for forming the adhesive layer 19, it is preferable to use an acrylic adhesive resin having both adhesiveness and flexibility. For example, a triblock represented by the formula A-B-A (wherein A and B each represent a different polymer block, A consists of a methacrylic acid alkyl ester unit, and B consists of an acrylic acid alkyl ester unit) Those containing a copolymer can be used. An acrylic resin mainly composed of the methacrylic acid alkyl ester unit and the acrylic acid alkyl ester unit in which the polymer blocks A and B have an alkyl group having 1 to 4 carbon atoms is preferable.

  Specific examples of these particularly preferred acrylic triblock copolymers include polymethyl methacrylate-b-poly (n-butyl acrylate) -b-polymethyl methacrylate, polymethyl methacrylate-b-polyacrylic acid n- Triblocks having the structure of formula ABA or ABC, such as butyl-b-polymethyl acrylate, polymethyl methacrylate-b-polyacrylate n-butyl-b-polyethyl acrylate, etc. Mention may be made of copolymers. Furthermore, an acrylic resin in which the polymer block A is a methyl methacrylate polymer block and the polymer block B is an n-butyl acrylate polymer block is preferable.

  The weight average molecular weights of the polymer block A and the polymer block B in the triblock copolymer are not necessarily limited, but are generally preferably in the range of 3,000 to 500,000, respectively. More preferably, it is in the range of ˜300,000. The weight average molecular weight of the entire triblock copolymer is not necessarily limited, but generally it is preferably in the range of 10,000 to 1,000,000, and in the range of 40,000 to 200,000. It is more preferable. Examples of the resin that satisfies these conditions include LA polymer manufactured by Kuraray Co., Ltd.

  The thickness of the adhesive layer 19 is 20 μm or more, preferably 50 μm or more and less than 500 μm. If the thickness is less than 20 μm, the adhesion to the material to be hidden 101 may be inferior, and if it exceeds 500 μm, the cost increases.

  (Peeling layer) Examples of the polyolefin resin forming the peeling layer 23 include α-olefins and modified products thereof, or copolymers of α-olefins and various vinyl compounds. From the viewpoints of releasability and cost, polyethylene and / or polypropylene, which are general-purpose resins, are preferably in the range of 50 μm to 200 μm. When the thickness is less than 50 μm, the film may be stretched or cut at the time of peeling, which may make the peeling operation difficult, which is not preferable. Moreover, even if it is 200 micrometers or more, since peelability does not improve and cost becomes high, it is unpreferable.

  Examples of polyethylene include ethylene homopolymers and ethylene / α-olefin copolymers composed of ethylene and other α-olefins. Specifically, for example, low density polyethylene, linear low density polyethylene, ethylene / α-olefin copolymer polymerized using a metallocene catalyst, medium density polyethylene, and high density polyethylene can be used.

  The pressure-sensitive adhesive layer 19 of the present invention is an acrylic pressure-sensitive adhesive resin, and its viscosity rapidly decreases at high temperatures. Therefore, in the presence of low-density polyethylene, linear low-density polyethylene, and metallocene catalyst that can be formed at low temperatures. The use of a polymerized ethylene / α-olefin copolymer is preferred.

  As the polypropylene, a propylene homopolymer and a propylene / α-olefin copolymer composed of propylene and another α-olefin are preferable, but the presence of a metallocene-based catalyst capable of forming a film at a low temperature as in the case of the polyethylene described above. Use of a propylene / α-olefin copolymer polymerized below is preferred.

  Of course, the polyolefin resin used as the release layer 21 can be made into a blend of one or more of polyethylene and polypropylene in consideration of moldability, peelability, and cost. .

  (Hiding layer) The hiding layer 23 is made of a polyolefin resin containing a filler and / or a colorant, and the hiding layer 23 has at least a total light transmittance of less than 1.5%, preferably less than 1.0%. When the total light transmittance is 1.5 or more, the concealability after pasting may be insufficient, and the description content may not be completely concealed.

  In order to improve the concealing property, the confining layer 23 includes, for example, titanium oxide, calcium carbonate, carbon black, quartz powder, kaolin clay, zeolite, talc, mica, mica, aluminum hydroxide, water in the polyolefin resin. A filler such as magnesium oxide or a colorant is mixed. One or more fillers and colorants may be used, and other additives may be added as long as the hiding property is not affected. Further, printing or other layers may be provided on the surface of the concealing layer.

  The thickness of the concealment layer 23 may be appropriately determined in consideration of concealability, workability, and cost, but is preferably in the range of 50 to 300 μm. If it is less than this range, the concealability is insufficient, and if this range is exceeded, there is little change in concealment, which is disadvantageous in terms of cost.

  (Peeling strength) When the information concealed with the concealment label 10 is read again, only the concealment layer 23 of the concealment label 10 is peeled off, but at this time, it peels between the concealment layer 23 and the transparent layer 11, The peel strength between the hiding layer 23 and the transparent layer 11 is preferably in the range of 0.05 to 2 N / 25 mm. If the peel strength is less than 0.05 N / 25 mm, the sheet may be turned over or peeled during transportation, and if it exceeds 2 N / 25 mm, the peel may be difficult.

  As a means for adjusting the peel strength, a hydrogenated diene copolymer can be added to the masking layer 23. The addition concentration of the hydrogenated diene copolymer is determined according to the peel strength between the transparent layer and the hiding layer, but is in the range of 0 to 25% by mass. Here, the vinyl aromatic compound used in the hydrogenated diene copolymer is styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N— Examples include diethyl-p-aminoethyl styrene and vinyl pyridine, and styrene and α-methyl styrene are particularly preferable. Conjugated dienes are 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5- Examples include diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc. In order to obtain a hydrogenated diene copolymer excellent in physical properties, 1,3-butadiene, isoprene 1,3-pentadiene is preferred.

  The hydrogenated diene copolymer includes the vinyl aromatic compound polymer block (a), a conjugated diene polymer, or a random copolymer block (b) of a vinyl aromatic compound and a conjugated diene, and a vinyl aromatic compound. The conjugated diene is obtained by hydrogenating a diene block copolymer containing at least (a) and (b) of the tapered block (c) in which the vinyl aromatic compound gradually increases. Here, the diene block copolymer preferably has a configuration of (a)-(b), (a)-(b)-(a), or (a)-(b)-(c). Further, the block (a) and the block (b) do not necessarily need to be clearly distinguished from each other, and a tapered portion where the vinyl aromatic compound gradually decreases as the block (a) shifts to the block (b). A configuration having Further, the hydrogenated diene copolymer of the present invention needs to be saturated by hydrogenation of 80% or more, preferably 90% or more, of the conjugated diene portion of the block (a). Here, when the hydrogenation rate is 80% or less, the heat resistance and weather resistance are poor. Examples of such a hydrogenated diene copolymer include Dynalon from JSR, Septon from Kuraray, Kraton from Kraton Polymer, Shibster from Kaneka, and the like.

  (Concealed material) The concealed material 101 is not particularly limited to postcards, credit cards, prepaid cards, lotteries, certificates, and the like. As shown in FIG. 2, the concealment material 101 has concealment information 103 on the surface thereof, and the information is concealed by attaching a concealment label 10 so as to cover the concealment information 103. The concealment information 103 is not particularly limited, such as an address, personal name, various symbols and numbers.

  (Attaching method) The peeling layer 21 of the concealment label 10 is peeled off to expose the adhesive layer 19 and attached to the concealment information 103 on the surface of the concealment material 101. The method may be hand-pasting, pressurizing with a roll, or using a labeler, and is not particularly limited. Since the adhesiveness of the acrylic resin layer to be the adhesive layer 19 of the present invention is used, specially strong heat treatment, pressurization, and decompression treatment are not required even when sticking, but heat treatment is performed depending on the final adhesive strength. , Pressurization treatment and decompression treatment can be used in combination.

  (Manufacturing method) The manufacturing method of the concealment label of this invention can provide the concealment layer 23, the transparent layer 10, the adhesion layer 10, and the peeling layer 10 by a multilayer coextrusion method in one step, and provides it at low cost. Can do. As the multilayer coextrusion method, a T-die coextrusion machine, an inflation coextrusion machine, or the like can be applied. Many conventional manufacturing processes, such as a laminating process of layer construction, a pressure-sensitive adhesive coating process, and a release paper attaching process, are unnecessary, and can be molded by a single coextrusion method. Can be provided at low cost.

  (Labeling) The concealment label 10 manufactured by the coextrusion method is in a wound state and is labeled. In order to form a label, the label is punched into a required shape and made into a sheet-like label, or a half-cut label that has penetrated the concealing layer 23 / transparent layer 10 / adhesive layer 10 and left the release layer 21. It can also be. Of course, in consideration of workability, it is also possible to make the masking layer half-cut so that it can be easily peeled off.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this. In addition, except a solvent, each composition of each layer is a mass part of solid content conversion.

(Example 1) A four-layer four-layer film comprising a transparent layer 10, an adhesive layer 10 and a release layer 10 composed of the following composition was subjected to a multilayer coextrusion method using a four-layer T-die type film forming machine in one step. The concealment label 10 of Example 1 was produced. There was no particular problem at the time of film formation, and the film could be formed stably.
The unit of density d is g / cm ³ , the unit of MFR is g / 10 minutes (200 ° C.) only for Kraton, and the other is g / 10 minutes (190 ° C.).
-Hidden layer: the following composition 150 μm
Ube Industries' Umerit 1540F 80 parts by mass
Titanium white 15 parts by mass
Clayton Co., Ltd. Clayton G1657 (MFR = 7) 5 parts by mass-Release layer: linear low density polyethylene 100 μm
(Ube Industries Umerit 1540F, d = 0.913, MFR = 4.0)
-Adhesive layer: Acrylic elastomer 100 μm
(Kuraray LA polymer LA2250, MFR = 25)
・ Transparent layer: Acrylic polymer 50μm
(Kuraray LA polymer LA4285, MFR = 1.5)
The peel strength between the transparent layer 11 and the masking layer 23 of the masking label 10 of Example 1 was 0.8 N / 25 mm. The total light transmittance of the hiding layer 23 was 0.5%.

(Example 2) A concealment label 10 of Example 2 was produced in the same manner as in Example 1 except that the following composition was used. There was no particular problem at the time of film formation, and the film could be formed stably.
-Hidden layer: the following composition 150μ
Ube Industries' Umerit 1520F 80 parts by mass
14 parts by weight of titanium white
1 part by mass of carbon black
Clayton Co., Ltd. Clayton G1657 (MFR = 7) 5 parts by mass-Release layer: linear low density polyethylene 100μ
(Ube Industries' Umerit 1520F, d = 0.913, MFR = 2.0)
-Adhesive layer: acrylic elastomer 100μ
(LA polymer LA2250, MFR = 25 manufactured by Kuraray)
-Transparent layer: acrylic polymer 50μ
(LA polymer LA4285 manufactured by Kuraray Co., Ltd., MFR = 1.5)
The peel strength between the transparent layer 11 and the masking layer 23 of the masking label 10 of Example 2 was 0.8 N / 25 mm. The total light transmittance of the hiding layer 23 was 0.1%.

(Evaluation) Using a tabletop laminator (Japan GBC, GL835PRO), the concealment label 10 of the wound-shaped example was cut into a 60 mm × 100 mm rectangle to form a single-wafer label, and the release layer 21 was peeled off and exposed. The adhesive layer 19 was attached to a postcard whose personal name was written on the back side at a speed of 0.6 m / min, a pressure of 0.3 MPa, and a room temperature to form a concealing postcard.
In any concealing postcard using the concealment label 10 of Examples 1-2, the personal name was unreadable. Furthermore, after leaving for one day, when the masking layer 23 of the masking label 10 was peeled off, the personal name could be read. Further, the masking layer 23 after being peeled off could not be pasted on the transparent layer 11 again.

  (Industrial Applicability) The concealment label of the present invention can be used mainly for public facilities, exercise facilities, partitions, security doors, safety glass for automobiles, and the like. Moreover, it is especially preferable as a reinforced film in the case of thin film glass, such as a liquid crystal display and a touch panel. However, it is not particularly limited as long as it is an application that needs to be protected by being attached to an object to be protected.

10: Concealment label 11: Transparent layer 19: Adhesive layer 21: Release layer 101: Protected material

Claims (5)

  A concealing layer made of a polyolefin resin containing a filler and / or a colorant, a transparent layer made of an acrylic resin, an adhesive layer made of an acrylic adhesive resin, and a release layer made of a polyolefin resin are laminated in this order. Concealment label characterized by comprising.   The acrylic adhesive resin of the adhesive layer has the formula A-B-A (wherein A and B each represent a different polymer block, A consists of a methacrylic acid alkyl ester unit, and B represents an acrylic acid alkyl ester unit. The polymer blocks A and B are mainly composed of a methacrylic acid alkyl ester unit and an acrylic acid alkyl ester unit having an alkyl group having 1 to 4 carbon atoms. The concealment label according to claim 1.   3. The concealing label according to claim 2, wherein the polymer block A is a methyl methacrylate polymer block, and the polymer block B is a butyl acrylate polymer block.   The concealment label according to any one of claims 1 to 3, wherein the polyolefin resin of the release layer is polyethylene and / or polypropylene.   It is a manufacturing method of the concealment label in any one of Claims 1-4, Comprising: The said concealment layer, the said transparent layer, the said adhesion layer, and the said peeling layer are manufactured by a multilayer coextrusion method, It is characterized by the above-mentioned. Manufacturing method of concealment label.

Images