Label for molded product, labeled molded product, and method for manufacturing labeled molded product

Abstract

To provide a label for molded article, a molded article with label, and a method for manufacturing a molded article with label in which both heating moldability and recyclability can be satisfied at a high level.SOLUTION: Provided is a label for molded article 1 including a substrate layer 10 including an amorphous polyester film, and a polyester-based adhesive layer 12 provided on at least one surface of the substrate layer 10, where initial adhesive force of the following is 1.0 N / 25 mm or more. Initial adhesive force: conforms to JIS Z0237:2009, and measured by a testing method in which a test piece of label for the molded article is adhered onto an amorphous polyester test plate while roller pressing the test piece under a 23°C environment, and the test piece is peeled off at an angle of 180° for the amorphous polyester test plate within 30 seconds from adhesion under the condition of peeling speed 300 mm / min.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a label for a molded article, a labeled molded article, and a method for manufacturing a labeled molded article. [Background technology]

[0002] Food products have traditionally been sold in containers made of resins such as polyester in the food sections of supermarkets and convenience stores. For example, molded products such as container bodies and lids are used as packaging containers for boxed lunches, prepared meals, eggs, etc. In particular, in recent years, the use of containers made of amorphous polyethylene terephthalate (A-PET) has been considered, with the aim of meeting required properties by reducing the liquid crystallinity of polyester to make it amorphous (non-crystalline).

[0003] For example, Patent Document 1 discloses a heat-resistant transparent A-PET container for storing food, which is characterized by being made by dry laminating a laminated sheet obtained by integrating an oriented A-PET sheet, which has been heated and primarily stretched, followed by primary heat setting, with an unstretched A-PET film or an unstretched A-PET sheet, and then heat-forming the laminated sheet in a mold of a thermoforming machine to enhance crystallization through secondary stretch-oriented crystallization caused by molding.

[0004] On the other hand, product labels (sometimes called "adhesive labels") are affixed to molded products such as containers to provide information such as the place of origin, expiration date, and barcode, as well as decorative features such as decoration.

[0005] For example, Patent Document 2 discloses a thermoforming polyester sheet characterized in that a copolymer polyester having a glass transition temperature of 85°C or less, or a blend resin containing such a polyester and other types of polyester, is disposed on the inner surface of an amorphous linear saturated polyester resin layer, which is a base layer, as a heat seal layer, and polybutylene terephthalate is compounded on the outer surface of the layer opposite the copolymer polyester for the purpose of preventing blocking with the heat seal layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-280218 [Patent Document 2] Japanese Patent Application Publication No. 07-009645 Summary of the Invention [Problem to be solved by the invention]

[0007] However, there is still room for improvement in the compatibility of thermoformability and recyclability with regard to the labels for molded products that are attached to the above-mentioned resin molded products.

[0008] For example, methods of producing labeled molded products by affixing the above-mentioned labels for molded products to molded products (for example, various containers such as container bodies and lids) include methods of affixing the labels for molded products using a label affixing device or the like. In this regard, the inventors have also considered methods of producing labeled molded products using a label affixing device or the like, in which the labels for molded products are affixed in advance to a resin sheet for thermoforming to form a laminate, and then a thermoforming step is performed to process and form this into the shape of the molded product. However, with conventional labels for molded products, even if such manufacturing methods are devised, the reality is that it has not been possible to achieve both high levels of thermoformability and recyclability.

[0009] The present invention has been made in consideration of the above circumstances, and its object is to provide a label for a molded product, a labeled molded product, and a method for manufacturing a labeled molded product, which can achieve both high levels of thermoformability and recyclability. [Means for solving the problem]

[0010] As a result of further intensive research in order to achieve the above-mentioned object, the inventors discovered that a label for molded products could be made which includes a base layer containing an amorphous polyester film and a polyester-based pressure-sensitive adhesive layer provided on at least one surface of the base layer, and which has an initial adhesive strength of 1.0 N / 25 mm or more, and thus completed the present invention.

[0011] That is, the present invention is as follows.

[0012] (1) The label for molded products comprises a base layer containing an amorphous polyester film and a polyester-based pressure-sensitive adhesive layer provided on at least one surface of the base layer, and has an initial adhesive strength of 1.0 N / 25 mm or more as described below. Initial adhesive strength: Adhesion strength measured in accordance with JIS Z0237:2009, in which a test piece of a label for molded products is attached to an amorphous polyester test plate using a roller in an environment of 23°C, and then the test piece is peeled off at an angle of 180° from the amorphous polyester test plate within 30 seconds of attachment at a peeling speed of 300 mm / min. (2) The label for molded products according to (1), wherein the amorphous polyester film has a heat shrinkage rate in the MD direction when treated at 100° C. for 5 minutes of 2.0% or more and 5.0% or less. (3) The label for molded products according to (1) or (2), wherein the amorphous polyester film is an amorphous polyethylene terephthalate (A-PET) film. (4) The label for molded products according to any one of (1) to (3), further comprising a coating layer provided on the surface of the base material layer opposite to the polyester-based pressure-sensitive adhesive layer. (5) The label for molded products is the label for molded products according to any one of (1) to (4), which is used by being stuck to the surface of a molded product made of a resin containing an amorphous polyester resin. (6) The label for molded products according to any one of (1) to (5), wherein all of the resin layers constituting the label for molded products are polyester resin layers. (7) The labeled molded product includes a resin molded product containing an amorphous polyester resin, and the label for molded products according to any one of (1) to (6) attached to the surface of the molded product. (8) This method for producing labeled molded products, in which labels for molded products are affixed to a molded product, comprises: (a) a labeling step in which labels for molded products are continuously affixed at regular intervals to the surface of a long polyester resin sheet to obtain a labeled sheet for molded products; (b) a thermoforming step in which a shape corresponding to the shape of the molded product is continuously formed into the labeled sheet for molded products by thermoforming to obtain a container sheet; and (c) a cutting step in which the container sheet is divided into molded product units.The labeled molded products are continuously produced by continuously performing at least steps (a) and (b), and the labels for molded products comprise a base layer containing an amorphous polyester film and a polyester-based pressure-sensitive adhesive layer provided on at least one surface of the base layer. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a label for a molded product, a labeled molded product, and a method for manufacturing a labeled molded product, which can achieve both high levels of thermoformability and recyclability. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a label with a release material according to this embodiment. [Figure 2] FIG. 2 is a partial cross-sectional view of a labeled molded product in which the label for molded products according to this embodiment is attached to the molded product. [Figure 3] FIG. 3 is a partial schematic view illustrating the method for producing a labeled molded product according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0016] In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the ratios shown in the drawings.

[0017] Furthermore, in this specification, terms with "abbreviation" attached indicate the meaning of the term excluding "abbreviation" within the scope of common technical knowledge of a person skilled in the art, and also include the meaning itself excluding "abbreviation." Furthermore, in this specification, the term "film" may also be called "sheet," etc., and vice versa.

[0018] FIG. 1 is a cross-sectional view of a label with a release material according to this embodiment.

[0019] The label 1 for molded products in this embodiment includes a base layer 10 containing an amorphous polyester film and a polyester-based adhesive layer 12 provided on at least one surface of the base layer 10, and has an initial adhesive strength of 1.0 N / 25 mm or more.

[0020] (Initial adhesive strength)

[0021] The label 1 for molded products has an initial adhesive strength of 1.0 N / 25 mm or more in an initial adhesive strength test. The lower limit of the initial adhesive strength is preferably 5.0 N / 25 mm or more, more preferably 7.0 N / 25 mm or more, and even more preferably 8.0 N / 25 mm or more. The upper limit of the initial adhesive strength is preferably 20.0 N / 25 mm or less. By setting the initial adhesive strength at or above the lower limit, problems such as label slippage and unintended peeling that may occur when the label is attached to a molded product 30 can be suppressed. Furthermore, in the manufacturing method of the labeled molded product 3 described below, problems such as label slippage and unintended peeling that may occur when labeling a polyester resin sheet for thermoforming can be suppressed, and the subsequent thermoforming can also be performed stably. Furthermore, by setting the initial adhesive strength at or below the upper limit, the label can be easily reattached, improving its convenience as a label.

[0022] The initial adhesive strength can be measured by the following method. Initial adhesive strength: Adhesion strength measured in accordance with JIS Z0237:2009, in which a test piece of label 1 for molded products is attached to an amorphous polyester test plate using a roller in an environment of 23°C, and then the test piece is peeled off at an angle of 180° from the amorphous polyester test plate within 30 seconds of attachment at a peeling speed of 300 mm / min.

[0023] The amorphous polyester test plate used in the above measurement of initial adhesive strength is an amorphous polyethylene terephthalate (A-PET) plate, and the test piece is pressed using a 2 kg rubber roller.

[0024] <Base material layer>

[0025] The base layer 10 includes an amorphous polyester film. Polyester can usually be obtained by polycondensation of a polycarboxylic acid such as terephthalic acid and a polyol component such as ethylene glycol, but amorphous (uncrystallized) polyester can also be obtained by, for example, rapidly cooling from a molten state. A specific example of how to produce an amorphous polyester film is to rapidly cool the film with a cooling roll during sheet extrusion processing to turn it into an amorphous state, thereby obtaining a film with high transparency, excellent thermoformability, etc.

[0026] Since amorphous polyester film has high transparency and excellent thermoformability, the label 1 for molded products according to this embodiment can exhibit advantages such as high transparency, excellent thermoformability, good designability, and excellent recyclability. For example, when recycling a resin molded product 30 that has outlived its usefulness, it is possible to carry out the recycling process on the labeled molded product 3 (e.g., various containers with a label) without removing the label 1 for molded products from the molded product 30.

[0027] Furthermore, when the molded article 30 is made of amorphous polyester resin, the mono-materialization can be further promoted, and thus recyclability is further improved. For example, when the molded article 30 is a container, polyester resins, especially amorphous polyester resins, are commonly used, but the combination of the materials of the label 1 for molded articles and the molded article 30 is a combination of materials that are compatible with each other, and therefore thermal processability and recyclability are further improved.

[0028] Furthermore, for example, when a molded product 30 to which the label 1 for molded products is affixed is heated and melted, the label 1 for molded products has good compatibility, so there is no need to separate the label 1 for molded products from the molded product 30, and the label can be collected in an integrated state and recycled. Furthermore, the properties of the recycled product are not deteriorated. These advantages contribute to the development of mono-materials, etc.

[0029] Furthermore, as will be described in detail later, the label 1 for molded products according to this embodiment also has advantages in terms of manufacturing process. When the label 1 for molded products uses an amorphous polyester film as the base layer 10, it is expected that a molded product (such as labeled molded product 3) with an integrated, transparent, and beautiful amorphous label can be efficiently manufactured by, for example, attaching the label 1 for molded products to a resin sheet for thermoforming in advance to form a laminate, and then carrying out a thermoforming step to process and mold this into the shape of the molded product 30.

[0030] For example, the label 1 for molded products can be attached to a resin sheet for thermoforming in advance, and then the sheet can be thermoformed into the shape of the molded product 30 (such as a container). This allows for improved productivity, high transparency, and good design. Furthermore, when recycling the labeled molded product 3, it is possible to carry out the regeneration process without removing the label 1 for molded products attached to the molded product 30.

[0031] Examples of amorphous polyester films include amorphous polyethylene terephthalate (A-PET) films. Among these, amorphous polyethylene terephthalate (A-PET) films are preferred because they have the above-mentioned advantages. Commercially available A-PET films can also be used, such as the "NOACRYSTAL" series manufactured by RP Toho Plastics Co., Ltd. and the "Kanelon" series manufactured by Shin-ei Kasei Co., Ltd.

[0032] In order to further enhance the advantages of the monomaterial material and further improve the various effects described above, it is preferable that all of the resin layers constituting the label 1 for molded products are polyester resin layers, and it is even more preferable that all of them are amorphous polyester films.

[0033] The amorphous polyester film of the base layer 10 preferably has a heat shrinkage rate in the MD (machine direction) when treated at 100°C for 5 minutes of 2.0% or more and 5.0% or less. The lower limit of the heat shrinkage rate is more preferably 2.5% or more, and even more preferably 3.0% or more. The upper limit of the heat shrinkage rate is more preferably 4.5% or less, and even more preferably 4.0% or less. The heat shrinkage rate can be measured by the following method. First, the film to be measured is cut into a strip of 100 mm in the MD and 10 mm in the CD (cross direction) to obtain a sample piece. This sample piece is left unstrained in a gear oven maintained at 100°C for 5 minutes. Then, it is removed to room temperature, and the length (B) of the sample piece in the MD after heat treatment is measured. The difference ((AB) / A(%)) between the length (A) in the MD direction of the sample piece before treatment and the length (B) in the MD direction of the sample piece after treatment can be calculated as the thermal shrinkage rate.

[0034] The base layer 10 may be any layer as long as it contains at least an amorphous polyester film, and may be, for example, a single layer or may be composed of two or more layers.

[0035] Even when the base layer 10 is composed of multiple layers, it is preferable that all of the layers constituting the base layer 10 are polyester films, more preferably amorphous polyester films. It is also preferable that all of the layers constituting the base layer 10 are polyethylene terephthalate films, more preferably amorphous polyethylene terephthalate (A-PET) films.

[0036] The thickness of the substrate layer 10 is not particularly limited and can be appropriately selected depending on the application, etc., but is preferably in the range of 25 μm to 500 μm, more preferably 30 μm to 200 μm, and even more preferably 40 μm to 150 μm. By making the thickness of the substrate layer 10 equal to or greater than the above-mentioned lower limit, the releasability from the release material layer 20 (e.g., release liner) during the labeling process, etc., is further improved. Furthermore, by making the thickness of the substrate layer 10 equal to or less than the above-mentioned upper limit, for example, the wound length when made into a label roll for installation in a labeling device can be sufficiently long, thereby reducing the frequency of roll replacement and further improving work efficiency. The substrate layer 10 may be obtained by a conventional film-forming method, such as an extrusion method, a calendar method, a solution coating method, or a casting method.

[0037] <Coating layer, etc.>

[0038] The label 1 for molded products according to this embodiment preferably further includes a coating layer 14 provided on the surface of the base layer 10 opposite the polyester-based pressure-sensitive adhesive layer 12. The coating layer 14 can be provided on the surface of the base layer 10. The coating layer 14 is preferably provided on the base layer 10 from the viewpoint of improving the adhesion of printing ink and further improving printability. The coating layer 14 can be printed as desired by a common printing method such as gravure printing, screen printing, letterpress printing, offset printing, or flexographic printing.

[0039] The material constituting the coating layer 14 is preferably one that has good adhesion to the material used as the base layer 10 (e.g., an amorphous polyester film such as A-PET film). Furthermore, from the viewpoint of recyclability, the material is preferably one that can be easily peeled from the base layer 10 by washing and immersion in an alkaline aqueous solution. A preferred configuration of the coating layer 14 includes an anchor layer (not shown) containing a water-based polyester resin and a print-receiving layer (not shown) on the surface of the anchor layer that contains a polyester urethane resin (e.g., a solvent-based polyester urethane). Here, "water-based" means aqueous, for example, water-soluble, water-dispersible, or water-suspendable.

[0040] Furthermore, in order to improve the adhesion between the base material layer 10 and the polyester-based pressure-sensitive adhesive layer 12, known surface treatments such as corona discharge treatment can be performed as desired. The surface treatment is not limited to the contact surface between the base material layer 10 and the polyester-based pressure-sensitive adhesive layer 12, but can also be performed on the contact surface between the base material layer 10 and the coating layer 14. This can further improve the printability of the label 1 for molded products according to this embodiment, and also allows it to be easily peeled from the anchor layer (not shown) with an alkaline aqueous solution.

[0041] <Polyester-based adhesive layer>

[0042] The polyester-based pressure-sensitive adhesive layer 12 can be formed from a polyester-based pressure-sensitive adhesive composition containing a polyester-based resin as a main component. The polyester-based resin used in the polyester-based pressure-sensitive adhesive layer 12 is not particularly limited, and known polyester-based resins can be used, such as polyester-based resins in the "Nichigo Polyester™" series manufactured by Mitsubishi Chemical Corporation (product names "NP-110S50EO," "SNT," "NP-120S45EO," etc.). The polyester-based resin used in the polyester-based pressure-sensitive adhesive layer 12 is produced, for example, by polycondensation of a polycarboxylic acid component and a polyol component in the presence of a catalyst.

[0043] Glass transition temperature (T g) is not particularly limited, but is preferably -70°C or higher and 0°C or lower from the viewpoint of room temperature adhesion, initial adhesive strength, etc. This allows the polyester-based pressure-sensitive adhesive layer 12 to have adhesiveness (pressure-sensitive adhesiveness) at room temperature and to be attached to the surface of a molded article made of a resin containing an amorphous polyester resin at room temperature. The glass transition temperature can be determined by measurement at a temperature rise rate of 10°C / min in accordance with JIS K7121:1987.

[0044] Number average molecular weight (M n The number average molecular weight (M) is not particularly limited, but from the viewpoint of cohesive strength, heat resistance, mechanical strength, adhesiveness, etc., it is preferably 5,000 or more and 100,000 or less, more preferably 10,000 or more and 100,000 or less, and even more preferably 15,000 or more and 80,000 or less. n ) are values calculated as standard polystyrene molecular weights measured by gel permeation chromatography (GPC) unless otherwise specified.

[0045] Furthermore, by crosslinking the polyester resin with a crosslinking agent, the cohesive strength can be further improved, and the performance as a pressure-sensitive adhesive can be further improved. Examples of such crosslinking agents include compounds having functional groups that react with hydroxyl groups and / or carboxyl groups contained in the polyester resin, such as polyisocyanate compounds and polyepoxy compounds. Among these, polyisocyanate compounds are preferred from the viewpoint of achieving a higher level of initial adhesive strength, mechanical strength, heat resistance, etc. The crosslinking agents may be used alone or in combination of two or more.

[0046] The amount of crosslinking agent to be added can be appropriately selected taking into consideration the molecular weight of the polyester resin, the intended use, etc., but it is preferable to add the crosslinking agent in a ratio such that the reactive groups contained in the crosslinking agent are 0.2 to 10 equivalents per equivalent of hydroxyl and / or carboxyl groups contained in the polyester resin, more preferably 0.5 to 5 equivalents, and even more preferably 0.5 to 3 equivalents. By adding such an amount, the cohesive strength is further improved based on the number of equivalents of the reactive groups contained in the crosslinking agent, and label slippage after application tends to be more effectively suppressed. In addition, deterioration in flexibility and initial adhesive strength can be more effectively suppressed, which tends to more effectively suppress peeling immediately after application.

[0047] The polyester-based pressure-sensitive adhesive composition may contain conventionally known additives such as hydrolysis inhibitors, softeners, ultraviolet absorbers, stabilizers, antistatic agents, and tackifiers, as well as other powdery or particulate additives such as inorganic or organic fillers, metal powders, and pigments, within the range that does not impair the effects of the present invention.

[0048] Furthermore, when the polyester-based adhesive layer 12 is formed by coating using a polyester-based adhesive composition, the solvent may be, for example, alcohols, acetone, ethyl acetate, acetic acid, tetrahydrofuran (THF), diethyl ether (DME), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), toluene, carbon tetrachloride, n-hexane, (water), and mixtures thereof.

[0049] Examples of alcohols include monoalcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, and phenethyl alcohol; diols such as ethylene glycol, propylene glycol, and butanediol; triols such as triethylene glycol; and polyols such as polyethylene glycol.

[0050] The storage modulus G' of the polyester-based pressure-sensitive adhesive layer 12 is 1×10 5Pa or more 100×10 5 Pa or less, and 5 Pa or more 50×10 5 It is more preferable that the storage modulus G' of the polyester-based pressure-sensitive adhesive layer 12 is equal to or less than the upper limit, the adhesive strength tends to be more easily ensured. If the storage modulus G' of the polyester-based pressure-sensitive adhesive layer 12 is equal to or more than the lower limit, the cohesive strength tends to be more easily ensured.

[0051] The storage modulus G' of the adhesive layer can be adjusted by appropriately changing the type, molecular weight, and compounding ratio of the monomers constituting the polymer (adhesive) contained in the polyester-based adhesive layer 12, as well as the degree of polymerization of the polymer, and, if a crosslinking agent is contained, the amount of crosslinking agent (crosslinking density of the polymer), etc.

[0052] The storage modulus G' of the polyester-based pressure-sensitive adhesive layer 12 can be measured using a dynamic viscoelasticity measuring device (TA Instruments Japan, device name "ARES"). A laminate having a polyester-based pressure-sensitive adhesive layer 12 with a thickness of 500 μm to 1 mm (e.g., 800 μm) formed between two release liners is punched into a disk with a diameter of 8 mm, and the release liners are removed to obtain a measurement sample. The storage modulus G' at 23°C is measured in a temperature range of -50°C to 150°C, at a heating rate of 5°C / min, and at a frequency of 1 Hz in shear mode.

[0053] The thickness of the polyester-based pressure-sensitive adhesive layer 12 can be selected appropriately depending on the application of the label for molded products 1. The thickness of the polyester-based pressure-sensitive adhesive layer 12 is preferably 1 μm or more and 50 μm or less, more preferably 5 μm or more and 50 μm or less, even more preferably 10 μm or more and 40 μm or less, and even more preferably 10 μm or more and 30 μm or less.

[0054] <Release material layer>

[0055] The label 1 for molded products of this embodiment may be formed into a label 2 for molded products with a release material by laminating a release material layer 20 (e.g., a release liner) on the surface of the polyester-based pressure-sensitive adhesive layer 12 side. The material for the release material layer 20 is not particularly limited as long as it is releasable from the polyester-based pressure-sensitive adhesive layer 12, and known materials can be used. Examples include paper such as glassine paper, coated paper, and laminated paper, and various plastic films coated with a release agent such as silicone resin. One aspect of the label 2 for molded products with a release material according to this embodiment is a structure in which a coating layer 14 is provided on one side of a base layer 10, and a polyester-based pressure-sensitive adhesive layer 12 and a release material layer 20 are sequentially laminated on the opposite side. When a label 1 for molded products with such a structure is attached to a molded product 30, the release material layer 20 is peeled off to expose the polyester-based pressure-sensitive adhesive layer 12, and the polyester-based pressure-sensitive adhesive layer 12 is brought into contact with the surface of the molded product 30 (adherend) and attached.

[0056] The thickness of the release material layer 20 can be selected appropriately depending on the application of the label 1 for molded products, but from the standpoint of handleability, it is preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 150 μm or less, and even more preferably 30 μm or more and 100 μm or less.

[0057] Furthermore, the label 1 for molded products may be provided with functional layers other than those described above as necessary, as long as the effects of this embodiment can be obtained.

[0058] <Manufacturing method for labels for molded products>

[0059] The manufacturing method of the label 1 for molded products according to the present embodiment is not particularly limited, and the label can be manufactured, for example, by a manufacturing method including a step of laminating a polyester-based pressure-sensitive adhesive layer 12 on the surface of the base layer 10. Examples of methods for laminating the polyester-based pressure-sensitive adhesive layer 12 on the surface of the base layer 10 include a method of forming the polyester-based pressure-sensitive adhesive layer 12 by applying a composition containing a polyester-based pressure-sensitive adhesive (a polyester-based pressure-sensitive adhesive composition) to the surface of the base layer 10. Examples of methods for applying the polyester-based pressure-sensitive adhesive composition include roll coating, spin coating, spray coating, bar coating, knife coating, roll knife coating, blade coating, die coating, and gravure coating.

[0060] When the label 2 for a molded product with a release material is produced, the release material layer 20 described above may be laminated on the surface of the polyester-based pressure-sensitive adhesive layer 12 .

[0061] <Molded product with label>

[0062] FIG. 2 is a partial cross-sectional view of a labeled molded product in which the label for molded products according to this embodiment is attached to the molded product.

[0063] The label 1 for molded products is used by being attached to the surface of a molded product 30 made of a resin containing an amorphous polyester resin. That is, the labeled molded product 3 is one in which the label 1 for molded products according to this embodiment is attached to the molded product 30. Specifically, the labeled molded product 3 includes a molded product 30 made of a resin such as an amorphous polyester resin, and the label 1 for molded products attached to the surface of the molded product 30. When the molded product 30 to be attached is composed of multiple layers, the label 1 for molded products is attached to the surface layer.

[0064] Examples of the molded article 30 include containers such as a container body and a lid, etc. Specific examples include, but are not limited to, blister packs, fruit cups, egg cartons, etc.

[0065] As described above, amorphous polyester resin, or even amorphous polyethylene terephthalate (A-PET), which has superior physical properties such as thermoformability over conventional biaxially oriented polyester resins, may be preferred as the material of the molded product 30. By using such a molded product 30 in combination with the label 1 for molded products of this embodiment, mono-materialization as a material progresses, and the product can be suitably used as a mono-material packaging material, particularly as a label-integrated container with excellent recyclability.

[0066] From this viewpoint, it is preferable that all of the resin layers constituting the label for molded products 1 are polyester resin layers, and all of the resin layers constituting the molded product 30 are polyester resin layers. Furthermore, it is preferable that all of the resin layers constituting the label for molded products 1 are amorphous polyethylene terephthalate (A-PET) resin layers, and all of the resin layers constituting the molded product 30 are amorphous polyethylene terephthalate (A-PET) resin layers. By using A-PET as a material for both the molded product 30 and the label for molded products 1, it is expected that the labeled molded product 3 as a whole will also have the various physical properties described above improved by A-PET.

[0067] <Manufacturing method for labeled molded products>

[0068] FIG. 3 is a partial schematic view illustrating the method for producing a labeled molded product according to this embodiment.

[0069] The method for manufacturing a labeled molded product 3 according to this embodiment is a method for manufacturing a labeled molded product in which a label for a molded product 1 is attached to a molded product 30, (a) a labeling step in which labels 1 for molded products are continuously attached at regular intervals to the surface of a long polyester resin sheet 40 to obtain a labeled sheet 4 for molded products; (b) a thermoforming step of continuously forming a shape corresponding to the shape of the molded product 30 on the label-attached sheet 4 for the molded product by thermoforming to obtain a container sheet; (c) a cutting step of dividing the container sheet into molded product units; At least steps (a) and (b) are continuously carried out to continuously produce a labeled molded product 3, and the label 1 for the molded product comprises a base layer 10 containing an amorphous polyester film and a polyester-based pressure-sensitive adhesive layer 12 provided on at least one surface of the base layer 10. One embodiment of the method is described below by way of example.

[0070] In the manufacturing method according to this embodiment, at least (a) a labeling step is performed, followed by (b) a thermoforming step. As described above, the material of the label 1 for molded products and the material of the molded product 30 obtained from a polyethylene resin sheet are an ideal combination for mono-material packaging materials. Therefore, even if these are integrated into the label-attached sheet 4 for molded products and then thermoforming is performed to form the shape of a container or the like, defects such as processing defects and peeling between the label 1 for molded products and the molded product 30 can be sufficiently suppressed. Furthermore, the occurrence of defective products is low, the yield is high, and continuous production is possible, making it economical.

[0071] In step (a), a long polyester resin sheet 40 is used. This will later become a component of the molded product 30. A long, approximately rectangular sheet can be used as the polyester resin sheet 40. Labels 1 for molded products are attached to the surface of the polyester resin sheet 40 at regular intervals in both the vertical and horizontal directions to obtain a labeled sheet 4 for molded products. The labels 1 for molded products can be attached continuously to the polyester resin sheet 40. For example, in FIG. 3, the labels 1 for molded products are attached continuously at regular intervals in both the vertical and horizontal directions to the polyester resin sheet 40 being conveyed in the conveying direction (arrow F). FIG. 3 illustrates an example in which the labels 1 for molded products are arranged in three rows (three in the width direction). However, the arrangement interval and conveying speed are not particularly limited, and any suitable conditions can be adopted. These conditions can be adjusted by appropriately changing the configuration and conditions of the labeling device used. As described above, since the label 1 for molded products has adhesiveness at room temperature, it is preferable to apply the label 1 for molded products to the polyester resin sheet 40 at room temperature in step (a). This eliminates the need for heat application in the labeling step, improving productivity.

[0072] In step (b), the label-attached sheet 4 for molded products obtained in step (a) is heated and softened using a vacuum / pressure molding machine or the like, and then shaped into a shape corresponding to the shape of the molded product 30 (for example, the shape of the container body or lid) using a mold or the like. Shaping can be performed by vacuum / pressure molding or the like. In this way, a container sheet with the shaped shape can be obtained.

[0073] In this embodiment, the polyester resin sheet 40 and the label 1 for molded products have good material affinity (e.g., compatibility, etc.), so the edges of the label 1 for molded products do not lift or peel, transparency is maintained, and high formability can be achieved. Furthermore, if the coating layer 14 of the label 1 for molded products is printed with ink, etc., the ink can be prevented from falling off. The molding conditions are not particularly limited, and can be adjusted to achieve suitable conditions by appropriately changing the configuration and conditions of the molding machine used, etc.

[0074] In step (c), after steps (a) and (b) are performed, the sheet is divided into molded products. For example, in step (b), the container sheets are conveyed in the state where they are formed in the thermoforming process and aligned vertically and horizontally at regular intervals. These containers are then cut into individual containers to obtain labeled molded products 3. In this embodiment, it is also possible to perform steps (a) and (b) continuously, and then divide the sheet into molded products in step (c). [Example]

[0075] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples in any way. Note that percentages and parts are by weight unless otherwise specified.

[0076] <Creating Label 1 for Molded Products>

[0077] (Polyester-based adhesive layer 12)

[0078] Polyester resin (manufactured by Mitsubishi Chemical Corporation, product name "Nichigo Polyester™ NP-110S50EO"); glass transition temperature (T g To 100 parts by mass (solid content) of the acrylic resin (temperature-controlled at -50°C or lower), 2 parts by mass (solid content) of a crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L") and 40 parts by mass of ethyl acetate were added and mixed to prepare a pressure-sensitive adhesive composition.

[0079] The resulting adhesive composition was applied to the surface of a release liner made of glassine paper coated with a silicone release agent using a knife coater so that the dried film thickness would be 25 μm, and then dried at 90° C. for 1 minute to form a polyester adhesive layer 12.

[0080] (Base layer 10, coating layer 14)

[0081] A 120 μm thick amorphous polyethylene terephthalate (A-PET) film (manufactured by RP Topla Co., Ltd., product name "NOACRYSTAL-M") was used as the base layer 10. A solvent-based polyester urethane resin was applied to one surface of this film using a Mayer bar, followed by drying to form a 1 μm thick print-receiving layer (polyester urethane resin layer). In this way, a coating layer 14 consisting of the print-receiving layer was formed on the surface of the base layer 10.

[0082] The amorphous polyethylene terephthalate film used as the base layer 10 had a thermal shrinkage rate of 3.5% in the MD direction when treated at 100° C. for 5 minutes.

[0083] Then, an amorphous polyethylene terephthalate (A-PET) film (manufactured by RP Topla Co., Ltd., product name "NOACRYSTAL-M") was attached to the surface opposite to the coating layer 14 on the polyester-based pressure-sensitive adhesive layer 12, and the film was taken up and left to stand at 23°C for 7 days to obtain a label for molded products 1. This was then rolled up to obtain a corresponding label roll.

[0084] (Initial adhesive strength) The required amount was cut from the label roll and formed into a sheet. This was left standing for 24 hours in a 23°C environment according to JIS Z0237:2009, after which the release liner was peeled off and the adhesive layer was attached to an amorphous polyethylene terephthalate (A-PET) plate using a 2 kg rubber roller under roller pressure. The adhesive strength was measured immediately after application and after 24 hours of standing under standard conditions. Specifically, the sheet was peeled off in a 180° direction at a test speed of 0.3 m / min using a tensile tester to measure the adhesive strength. The numerical value is converted to the peel force per 25 mm of sheet width (N / 25 mm). The initial adhesive strength of the label 1 for molded products in the above example was 5.5 N / 25 mm.

[0085] Next, the coating layer 14 of the label 1 for molded products was printed using UV-curable ink.

[0086] <Production of labeled molded product 3>

[0087] ((a) Labeling process)

[0088] The label roll was cut to a length of 300 m and a width of 60 mm, and punched to a label size of 35 mm x 35 mm with a label spacing of 3 mm. This label roll was used to continuously apply labels to a thermoforming A-PET sheet (polyester resin sheet 40) using a labeling device at a labeling speed of 100 m / min, yielding a labeled sheet 4 for molded products (an A-PET sheet for thermoforming with a label 1 for molded products attached). The resulting labeled sheet 4 for molded products was visually inspected for any peeling or lifting of the labels at the edges, etc.

[0089] ((b) Thermoforming process ~ (c) Cutting process)

[0090] Labeled sheet 4 for molding was heated to a surface temperature of 120°C using a vacuum / pressure forming machine to soften it, and then vacuum / pressure formed using a female aluminum mold under 0.5 MPa of pressure to obtain a container sheet with a shaped shape. After the above-described steps (a) and (b) were performed continuously, a cutting process was performed to divide the container sheet into molded product units, yielding food tray container lids (heat-resistant transparent A-PET container lids) with openings (172 mm wide x 88 mm long, 22 mm deep). Visual inspection of the resulting food tray container lids confirmed that there was no peeling of the label at the edge, transparency, no deformation, and no loss of ink on the printed surface of the label. [Explanation of symbols]

[0091] 1: Labels for molded products 2: Labels for molded products with release liner 3: Molded product with label 4: Label sheet for molded products 10: Base material layer 12: Polyester adhesive layer 14: Coat layer 20: Release material layer 30: Molded product 40: Polyester resin sheet

Claims

1. a substrate layer including an amorphous polyester film; a polyester-based pressure-sensitive adhesive layer provided on at least one surface of the base material layer; Including, The initial adhesive strength is 1.0 N / 25 mm or more. Labels for molded products. Initial adhesive strength: Adhesion strength measured in accordance with JIS Z0237:2009, in which a test piece of a label for molded products is attached to an amorphous polyester test plate while being pressed with a roller in an environment of 23°C, and the test piece is peeled off at an angle of 180° from the amorphous polyester test plate within 30 seconds of attachment at a peeling rate of 300 mm / min.

2. The amorphous polyester film has a heat shrinkage rate in the MD direction of 2.0% or more and 5.0% or less when treated at 100°C for 5 minutes. The label for molded products according to claim 1.

3. The amorphous polyester film is an amorphous polyethylene terephthalate (A-PET) film. The label for molded products according to claim 1 or 2.

4. The adhesive sheet further includes a coating layer provided on a surface of the base layer opposite to the polyester-based pressure-sensitive adhesive layer. The label for molded products according to any one of claims 1 to 3.

5. The label for molded products is used by being attached to the surface of a molded product made of a resin containing an amorphous polyester resin. The label for molded products according to any one of claims 1 to 4.

6. All of the resin layers constituting the label for molded products are polyester resin layers. The label for molded products according to any one of claims 1 to 5.

7. a resin molded article containing an amorphous polyester resin; The label for molded products according to any one of claims 1 to 6 attached to the surface of the molded product; Labeled articles, including:

8. A method for manufacturing a labeled molded product in which a label for a molded product is attached to a molded product, comprising: (a) a labeling step of continuously attaching labels for molded products at regular intervals to the surface of a long polyester resin sheet to obtain a labeled sheet for molded products; (b) a thermoforming step in which a shape corresponding to the shape of the molded product is continuously formed on the label-attached sheet for the molded product by thermoforming to obtain a container sheet; (c) a cutting step of dividing the container sheet into molded articles; Including, The labeled molded article is continuously produced by continuously carrying out at least the steps (a) and (b), The label for molded products includes a base layer containing an amorphous polyester film and a polyester-based pressure-sensitive adhesive layer provided on at least one surface of the base layer. A method for manufacturing labeled molded articles.

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