Films and packaging materials

Abstract

To provide a film and a packaging material which can protect an article from light sufficiently, which is present on the other side thereof and enables the other side thereof to be visible without performing an action to deform the film.SOLUTION: A film comprises first and second surfaces. The film comprises first and second portions. The first portion contains a chromic material and changes light transmittance by an external stimulation. The second portion has different characteristics from the first portion. A light transmittance of the first portion varies between a first transmittance and a second transmittance which is higher than the first transmittance. The second transmittance is higher than the transmittance of the second portion. On at least one of the first and second surfaces, the first portion is exposed to the outside.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to films and packaging materials. [Background technology]

[0002] JP 2020-138542 A (Patent Document 1) discloses a temperature-sensitive dye film. In this temperature-sensitive dye film, a temperature-sensitive dye layer is sandwiched between a base layer and a surface layer. According to this temperature-sensitive dye film, the temperature-sensitive dye layer develops or loses color in response to temperature changes, allowing the user to check the surrounding temperature changes at a glance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-138542 A Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, there are cases where an object is protected from light by covering it with a film. Generally, the light transmittance of the film used for such a purpose is low, so in order to check the condition of the object covered with the film, it is necessary to deform the film, such as by tearing it. However, such an action is time-consuming.

[0005] The present invention has been made to solve such problems, and its object is to provide a film and packaging material that can adequately protect objects located behind it from light, while allowing the objects behind it to be seen without deforming the film. [Means for solving the problem]

[0006] A film according to an aspect of the present invention has a first and a second surface. The film comprises a first and a second portion. The first portion includes a chromic material and has a light transmittance that changes in response to an external stimulus. The second portion has properties different from those of the first portion. The light transmittance of the first portion changes between a first transmittance and a second transmittance that is higher than the first transmittance. The second transmittance is higher than the light transmittance of the second portion. At least one of the first and second surfaces of the first portion is exposed to the outside.

[0007] In this film, the light transmittance of the first portion changes between the first transmittance and the second transmittance in response to an external stimulus. Since the second transmittance is higher than the light transmittance of the second portion, by applying an external stimulus, the user can more easily view the other side of the film through the first portion whose light transmittance has become the second transmittance without deforming the film. In particular, in this film, since the first portion is exposed to the outside on at least one of the first and second surfaces, the responsiveness of the change in light transmittance due to an external stimulus is high. Therefore, with this film, the user can more easily change the light transmittance of the first portion to the second transmittance, and can more easily view the other side of the film through the first portion whose light transmittance has become the second transmittance.

[0008] In the above film, when each of the first and second surfaces is viewed, the first portion may have an area that is not covered by the second portion.

[0009] In the above film, the second portion may have a light transmittance of 20% or less.

[0010] In the film, the second transmittance may be 50% or more.

[0011] In the above film, each of the first and second portions may extend in the machine direction of the film, and the first and second portions may be arranged alternately in the width direction of the film.

[0012] In this film, the first and second portions are alternately arranged in the width direction of the film. Therefore, with this film, the first portions are arranged at predetermined intervals, so that a user can see a wide range behind the film through the first portions having the second light transmittance.

[0013] A packaging material according to another aspect of the present invention is for packaging an article. The packaging material is constituted by the above-mentioned film.

[0014] With this packaging material, by applying an external stimulus to the packaging material without opening the package, a user can more easily view the inside of the packaging material through the first portion, which has a second light transmittance. Effect of the Invention

[0015] According to the present invention, it is possible to provide a film and packaging material that can adequately protect an object located on the other side from light, and that allows the object on the other side to be seen without deforming the film. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram illustrating a part of a plane of a film. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section taken along line II-II of FIG. [Diagram 3] FIG. 11 is a diagram illustrating a cross section of a film in a first modified example. [Figure 4] FIG. 13 is a diagram illustrating a plane of a film in a second modified example. [Diagram 5] FIG. 5 is a diagram showing a schematic cross section taken along line VV of FIG. 4. [Figure 6] FIG. 2 is a diagram showing an example of a bag formed from a film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated. In addition, each drawing is partially enlarged or reduced as necessary for ease of understanding.

[0018] [1. Film composition] Fig. 1 is a diagram that shows a part of the plane of a film 10 according to the present embodiment. Fig. 2 is a diagram that shows a cross section taken along line II-II in Fig. 1. The film 10 is used, for example, for packaging purposes, medical purposes, building materials, optical purposes, electrical products, interior decoration purposes, or light-shielding purposes.

[0019] As shown in FIG. 1 and FIG. 2, the film 10 has a first surface (e.g., a front surface) 31 and a second surface (e.g., a back surface) 32, and includes a plurality of first portions 11 and a plurality of second portions 12. Each of the first portions 11 and the second portions 12 extends in the machine direction (MD (Machine Direction)) of the film 10. In the transverse direction (TD (Transverse Direction)) of the film 10, the length of the first portions 11 is shorter than the length of the second portions 12. Therefore, in a plan view of the film 10, the area of ​​the first portions 11 is smaller than the area of ​​the second portions 12. In each of the first surface 31 and the second surface 32, the first portions 11 are exposed to the outside. That is, the first portions 11 have areas that are not covered by the second portions 12.

[0020] The first portions 11 and the second portions 12 are arranged alternately in the width direction of the film 10. In the film 10, the first portions 11 and the second portions 12 form a stripe pattern.

[0021] The first portion 11 is made of, for example, a material in which a chromic material and a resin material are dispersed and mixed. Here, the chromic material is a material whose optical properties (for example, transmittance, color, color tone, fluorescence intensity, refractive index, reflectance) change reversibly or irreversibly in response to an external stimulus. Examples of the external stimulus include temperature, light, water, pH, pressure, and electrical stimuli.

[0022] Examples of chromic materials that can be used include thermochromic materials, photochromic materials, hydrochromic materials, pH-responsive materials (eg, halochromic materials or acidichromic materials), piezochromic materials, and electrochromic materials.

[0023] Thermochromic materials are materials whose optical properties change reversibly when heated. Photochromic materials are materials whose optical properties change reversibly when irradiated with light. Hydrochromic materials are materials whose optical properties change reversibly when hydrated. pH-responsive materials are materials whose optical properties change reversibly when pH changes. Piezochromic materials are materials whose optical properties change reversibly when pressure is applied. Electrochromic materials are materials whose optical properties change reversibly when electricity is applied. As thermochromic materials, photochromic materials, hydrochromic materials, pH-responsive materials, piezochromic materials, and electrochromic materials, various known materials can be used. For example, examples of thermochromic materials include Sakura Color (reversible), Chromicolor (reversible) from Matsui Color Chemical Industry Co., Ltd., and Thermolock (quasi-irreversible) from Matsui Color Chemical Industry Co., Ltd. Examples of photochromic materials include Photopia Color (reversible) from Matsui Pigment Chemical Industry Co., Ltd., and Photolock (irreversible) from Matsui Pigment Chemical Industry Co., Ltd. These are merely examples, and various chromic materials such as irreversible type, heat accumulation type, quasi-reversible type, and reversible type can be used. For example, in thermochromic materials, examples of irreversible types include inorganic materials using metal salts and organic materials using a thermal recording method. Examples of reversible types include inorganic materials using metal complex salts, organic materials using condensed aromatic ring-substituted ethylene derivatives, organic materials using liquid crystals (e.g., cholesteric liquid crystals), and organic materials using Metamocolor (registered trademark).

[0024] As the resin material, a general extrusion resin can be used. Examples of the resin material include polyolefin resins such as polyethylene and polypropylene, styrene resins such as polystyrene, acrylic resins such as polymethyl methacrylate, polyamide resins such as polyamide (nylon 6, nylon 66, etc.), poly m-phenylene isophthalamide, and poly p-phenylene terephthalamide, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polyarylate, cycloolefin polymers such as norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof, vinyl chloride, polyimide, polyamideimide, polyphenylene ether, polyether ketone, polyether ether ketone, polycarbonate, polysulfone resins such as polysulfone and polyether sulfone, polyphenylene sulfide, silicone resins, and combinations of two or more of these polymers.

[0025] The first portion 11 is configured such that the light transmittance is changed by an external stimulus due to the chromic material. For example, the light transmittance of the first portion 11 is reversibly changed between a first transmittance and a second transmittance by an external stimulus.

[0026] The first transmittance is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. In other words, the first transmittance is preferably a transmittance that can protect an object covered by the film 10 from light. In this specification, each transmittance refers to "total light transmittance." Each transmittance is measured using a Haze Meter NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd., according to a test method in accordance with JIS K 7361-1.

[0027] Moreover, the second transmittance is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. In other words, the second transmittance is preferably a transmittance that allows a user to visually recognize an object covered by the film 10.

[0028] The second portion 12 is made of, for example, a material in which a black or white pigment and a resin material are dispersed and mixed. The resin material may be the same material as the resin material in the first portion 11, or may be a different material. Examples of black pigments include carbon black, carbon nanotubes (CNT), graphene, and carbon nanofibers. Examples of white pigments include titanium oxide, silica, fluorine-based fillers (for example, PTFE, PFA), clay minerals (for example, talc, mica), and boron nitride. The second portion 12 contains an amount of pigment that provides a transmittance of the second portion 12 that can protect an object covered by the film 10 from light.

[0029] In this way, the second portion 12 is colored, for example, black or white, and the light transmittance of the second portion 12 is lower than the second transmittance of the first portion 11. The light transmittance of the second portion 12 does not change due to an external stimulus. The light transmittance of the second portion 12 is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less.

[0030] For example, an object such as an electronic component may be packaged in a film having a low light transmittance in order to prevent static electricity. For example, by packaging an electronic component in a film entirely made up of the second portion 12, the electronic component can be prevented from static electricity. Also, for example, an object such as a UV-curable material may be packaged in a film having a low light transmittance in order to prevent hardening. For example, by packaging a UV-curable material in a film entirely made up of the second portion 12, unintended hardening of the UV-curable material is suppressed. However, when it becomes necessary to check an electronic component covered with such a film, for example, to check for defective products or inventory, it is necessary to deform the film, such as by tearing the film. Such an action is time-consuming.

[0031] In the film 10 according to the present embodiment, the light transmittance of the first portion 11 changes between the first transmittance and the second transmittance in response to an external stimulus. Since the second transmittance is higher than the light transmittance of the second portion 12, by applying an external stimulus, the user can more easily view the contents (e.g., electronic components, UV-curable materials) packaged by the film 10 through the first portion 11 whose light transmittance has become the second transmittance without deforming the film 10. In particular, in the film 10, since the first portion 11 is exposed to the outside on both the first surface 31 and the second surface 32, the response of the change in light transmittance due to an external stimulus is high. Therefore, according to the film 10, the user can more easily change the light transmittance of the first portion 11 to the second transmittance, and can more easily view the other side of the film through the first portion 11 whose light transmittance has become the second transmittance.

[0032] Furthermore, in the film 10, the first portions 11 and the second portions 12 are arranged alternately in the width direction of the film 10. Therefore, according to the film 10, the first portions 11 are arranged at predetermined intervals, and therefore the user can visually recognize the contents packaged by the film 10 over a wide range through the first portions 11 whose light transmittance has become the second transmittance. The film 10 can be produced by, for example, a coextrusion method, lamination processing, printing, or a 3D printer.

[0033] [2. Features] As described above, in the film 10 according to the present embodiment, the light transmittance of the first portion 11 changes between the first transmittance and the second transmittance in response to an external stimulus. Since the second transmittance is higher than the light transmittance of the second portion 12, by applying an external stimulus, the user can more easily view the contents packaged by the film 10 through the first portion 11 whose light transmittance has become the second transmittance without deforming the film 10. In particular, in the film 10, since the first portion 11 is exposed to the outside on both the first surface 31 and the second surface 32, the response of the change in light transmittance due to an external stimulus is high. Therefore, according to the film 10, the user can more easily change the light transmittance of the first portion 11 to the second transmittance, and can more easily view the other side of the film through the first portion 11 whose light transmittance has become the second transmittance.

[0034] [3. Modifications] Although the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0035] <3-1> In the above embodiment, both the first surface 31 and the second surface 32 are exposed to the outside. However, both the first surface 31 and the second surface 32 do not necessarily have to be exposed to the outside. For example, only one of the first surface 31 and the second surface 32 may be exposed to the outside.

[0036] Fig. 3 is a diagram showing a schematic cross section of a film 10A in the first modified example. As shown in Fig. 3, the film 10A includes a film body layer 13 and a base layer 14. The film body layer 13 has the same configuration as the film 10 according to the above embodiment. In the film 10A, the base layer 14 is formed on the second surface 32. The base layer 14 is, for example, a transparent layer. Such a configuration may be used.

[0037] <3-2> In film 10 according to the above embodiment, first portions 11 and second portions 12 are arranged alternately in the width direction of film 10. However, the arrangement of first portions 11 and second portions 12 is not limited to this.

[0038] Fig. 4 is a diagram showing a schematic plan view of film 10B in the second modified example. Fig. 5 is a diagram showing a schematic VV cross section of Fig. 4. As shown in Figs. 4 and 5, film 10B includes a first portion 21 and a second portion 22. The first portion 21 is made of, for example, the same material as the first portion 11 in the above embodiment. The second portion 22 is made of, for example, the same material as the second portion 12 in the above embodiment.

[0039] In film 10B, a circular first portion 21 is formed in a substantially central portion in a plan view, and a second portion 22 is formed so as to surround first portion 21. With this configuration, a user can easily view the substantially central portion of an item packaged in film 10B through first portion 21, whose light transmittance has become the second transmittance.

[0040] <3-3> A packaging bag (an example of a packaging material) may be formed from the film 10 according to the above embodiment. For example, a bag may be formed by overlapping two sheets of the film 10 and bonding three of the four sides to each other.

[0041] Fig. 6 is a diagram showing a schematic view of an example of a bag 100 formed by the film 10. As shown in Fig. 6, in the bag 100, first portions 11 and second portions 12 of the film 10 are formed alternately. According to the bag 100, by applying an external stimulus to the film 10, the user can more easily view the contents in the bag 100 through the first portions 11, whose light transmittance has become the second transmittance, without breaking the bag 100.

[0042] <3-4> In addition, in film 10 according to the above embodiment, the length of first portion 11 in the width direction of film 10 is shorter than the length of second portion 12. However, the length of first portion 11 in the width direction of film 10 may be longer than the length of second portion 12. In other words, the area of ​​first portion 11 may be larger than the area of ​​second portion 12.

[0043] <3-5> In addition, in the film 10 according to the above embodiment, the method of making the second portion 12 white is not limited to the method of dispersing and mixing a resin material and a white pigment. For example, the second portion 12 may be made white by alloying the resin material. Also, for example, the second portion 12 may be made white by using a crystalline resin material as the resin material. [Explanation of symbols]

[0044] 10, 10A, 10B, film, 11, 21 first part, 12, 22 second part, 13 film main body layer, 14 base material layer, 31 first surface, 32 second surface, 100 bag.

Claims

1. A film for use in packaging electronic components or UV-curable materials, the film having first and second surfaces, A first portion including a chromic material and having a light transmittance that changes in response to an external stimulus; a second portion having a different characteristic from the first portion; In a plan view, an area of ​​the first portion is smaller than an area of ​​the second portion, the transmittance of the first portion varies between a first transmittance and a second transmittance greater than the first transmittance; the first transmittance is 20% or less; the second transmittance is greater than the transmittance of the second portion; the transmittance of the second portion is less than or equal to 20%; At least one of the first and second surfaces, the first portion is exposed to the outside, When the transmittance of the first portion becomes the second transmittance, the other side of the film is visible through the first portion. film.

2. The film of claim 1 , wherein when viewed on each of the first and second surfaces, the first portion has an area that is not covered by the second portion.

3. The film of claim 1 or claim 2, wherein the second transmittance is 50% or more.

4. each of the first and second portions extending in a machine direction of the film; The film according to claim 1 , wherein the first and second portions are alternately arranged in the width direction of the film.

5. A packaging material for packaging the electronic component or the UV-curable material, comprising: A packaging material comprising the film according to any one of claims 1 to 4.

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