Recycled film

Abstract

To provide a recycled film with a multilayer structure that is resistant to delamination between layers. [Solution] The recycled film comprises a first resin layer and a second resin layer laminated on one side of the first resin layer. The first resin layer contains recycled resin raw material made from a resin molded product having a printed layer. The average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more. The haze value of the recycled film is 14% or less.

Description

Technical Field

[0001] The present invention relates to a recycled film.

Background Art

[0002] In recent years, plastic waste has become a global problem, such as marine pollution. Therefore, resource recycling, such as recycling plastic products that were previously discarded as resources, has attracted attention. For example, Patent Document 1 discloses a method of manufacturing recycled plastic (pellets) with less coloring, foreign matter, and air bubbles by removing a printing layer from a packaging material containing a printing layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the present inventors manufacture a recycled film having a multilayer structure using a recycled resin raw material produced from a plastic product, they noticed a phenomenon that the adhesion strength (interlayer strength) between the layer containing the recycled resin raw material included in the recycled film and the layer adjacent thereto decreases. When the interlayer strength decreases, peeling between layers may easily occur. As a result of further investigation, the present inventors found that this phenomenon is caused by components derived from the printing layer contained in the recycled resin raw material.

[0005] An object of the present invention is to provide a recycled film having a multilayer structure in which layers are difficult to peel off.

Means for Solving the Problems

[0006] Item 1. A first resin layer, A second resin layer laminated on one surface of the first resin layer Equipped with, The first resin layer includes a recycled resin raw material made from a resin molded product having a printed layer, The average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more. The haze value is 14% or less. Recycled film.

[0007] Item 2. Contains titanium in a weight percentage of 0.1 ppm or more and 20.0 ppm or less. Recycled film as described in item 1.

[0008] Item 3. The resin molded product includes at least one of the following: polystyrene resin, polyester resin, polyolefin resin, and polyamide resin. Recycled film as described in item 1 or 2.

[0009] Item 4. It is a heat-shrinkable film. Recycled film as described in any of items 1 to 3. [Effects of the Invention]

[0010] According to the present invention, a recycled film with a multilayer structure that is resistant to delamination between layers is provided. [Brief explanation of the drawing]

[0011] [Figure 1] A cross-sectional view of a recycled film according to one embodiment. [Figure 2] A plan view of a product film before the film edges are cut off, according to one embodiment. [Figure 3] A cross-sectional view of a product film according to one embodiment. [Figure 4] A schematic block diagram showing a resource recycling system according to one embodiment. [Figure 5] A diagram showing the configuration of a film manufacturing apparatus according to one embodiment. [Figure 6] A graph showing the results of four interlayer strength measurements for each film related to the reference example, Examples 1 and 2, and the comparative example.

Mode for Carrying Out the Invention

[0012] Hereinafter, a recycled film according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated. Also, for ease of understanding, each drawing is schematically drawn with appropriate omission or exaggeration of the subject.

[0013] [1. Configuration of Recycled Film] The recycled film 1 according to the present embodiment is a packaging material in the form of a film or label or the like that can be used in various fields such as food, beverages, pharmaceuticals, medical products, chemicals, cosmetics, toiletries, industrial supplies, and agricultural supplies. The recycled film 1 is used, for example, for packaging various containers such as plastic containers, glass containers, and paper containers.

[0014] When assuming the above uses, from the viewpoint of strength, the thickness of the recycled film 1 is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. From the viewpoints of economy and environmental friendliness, the thickness of the recycled film 1 is preferably 60 μm or less, more preferably 50 μm or less, even more preferably 40 μm or less, even more preferably 35 μm or less, even more preferably 30 μm or less, and even more preferably 25 μm or less.

[0015] Furthermore, when assuming the above uses, from the viewpoint of ensuring the transparency of the recycled film 1, the haze value of the recycled film 1 is preferably 14% or less, more preferably 12% or less, even more preferably 10% or less, even more preferably 8% or less, and even more preferably 7% or less.

[0016] The recycled film 1 is, for example, a heat-shrinkable film. In this case, the recycled film 1 is heat-shrunk by being heated and is attached to the container by adhering to the outer surface of the container along the outer shape of the container. The recycled film 1 is, for example, formed into a tubular shape, covered on the container so as to cover the container from the outside, and then heat-shrunk and attached to the container. The recycled film 1 is, for example, formed into a tubular shape by overlapping both ends in the TD (Transverse Direction) and sealing the overlapped portion in the MD (Machine Direction). In this case, when the recycled film 1 is attached to the container as a label, typically, the TD of the recycled film 1 corresponds to the lateral direction of the container, and the MD of the recycled film 1 corresponds to the longitudinal direction of the container.

[0017] When assuming the above applications, the recycled film 1 is preferably a uniaxially stretched film with the TD as the main shrinkage direction. The stretching ratio in the main shrinkage direction of the recycled film 1 is preferably 300% or more, more preferably 400% or more, and even more preferably 500% or more. The stretching ratio in the same direction is preferably 700% or less, more preferably 650% or less, and even more preferably 600% or less. Also, the stretching ratio in the direction orthogonal to the main shrinkage direction of the recycled film 1 is preferably 120% or more, more preferably 125% or more, and even more preferably 130% or more. The stretching ratio in the same direction is preferably 180% or less, more preferably 170% or less, even more preferably 160% or less, even more preferably 150% or less, and even more preferably 140% or less.

[0018] The heat shrinkage rate of recycled film 1 in the main shrinkage direction is preferably 55% or more, and more preferably 65% ​​or more, when immersed in 98°C hot water for 10 seconds. Furthermore, the heat shrinkage rate in the same direction is preferably 85% or less, and more preferably 80% or less, when immersed in 98°C hot water for 10 seconds. The heat shrinkage rate of recycled film 1 in the direction perpendicular to the main shrinkage direction is preferably 0% or more, and more preferably 5% or more, when immersed in 98°C hot water for 10 seconds. Furthermore, the heat shrinkage rate in the same direction is preferably 25% or less, and more preferably 20% or less, when immersed in 98°C hot water for 10 seconds.

[0019] Figure 1 is a cross-sectional view of the recycled film 1. In this example, the recycled film 1 has a three-layer structure and includes a first resin layer 11, a second resin layer 12, and a third resin layer 13. The first resin layer 11 is an intermediate layer and is formed between the second resin layer 12 and the third resin layer 13 in the thickness direction of the recycled film 1. In other words, the second resin layer 12 is laminated on one side of the first resin layer 11, and the third resin layer 13 is laminated on the other side of the first resin layer 11. The second resin layer 12 and the third resin layer 13 are each surface layers. In other words, one of the second resin layer 12 and the third resin layer 13 forms one surface (outermost surface) of the recycled film 1, and the other forms the other surface (outermost surface) of the recycled film 1. The first resin layer 11 and the adjacent second resin layer 12 may be bonded together via an adhesive layer. The first resin layer 11 and the adjacent third resin layer 13 may also be bonded together via an adhesive layer. The recycled film 1 is manufactured, for example, by feeding the raw materials for each layer contained in the recycled film 1 (the first resin layer 11, the second resin layer 12, and the third resin layer 13, and the adhesive layer, if any) into an extruder and co-extruding them.

[0020] The first resin layer 11, the second resin layer 12, and the third resin layer 13 each contain a resin. The resin contained in the first resin layer 11, which is an intermediate layer, may be of one type or multiple types. The resin contained in the second resin layer 12 and the third resin layer 13, which are surface layers, may also be of one type or multiple types. The amount of resin contained in each of the first resin layer 11, the second resin layer 12, and the third resin layer 13 is preferably 50 wt% or more, more preferably 60 wt% or more, even more preferably 70 wt% or more, even more preferably 80 wt% or more, even more preferably 90 wt% or more, and even more preferably 95 wt% or more. Each of the first resin layer 11, the second resin layer 12, and the third resin layer 13 may contain additives. Examples of additives include antiblocking agents, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, fluorescent whitening agents, etc.

[0021] The first resin layer 11, the second resin layer 12, and the third resin layer 13 may each contain a specific type of resin as their main component. In this specification, "main component" means the component that accounts for the largest weight relative to the total weight. The amount of the main component resin contained in each of the first resin layer 11, the second resin layer 12, and the third resin layer 13 is preferably 50 wt% or more, more preferably 60 wt% or more, even more preferably 70 wt% or more, even more preferably 80 wt% or more, even more preferably 90 wt% or more, and even more preferably 95 wt% or more.

[0022] Examples of the types of resins contained in the first resin layer 11, the second resin layer 12, and the third resin layer 13 include polystyrene resins, polyester resins, polyolefin resins, and polyamide resins.

[0023] Examples of polystyrene resins include homopolymers of styrene monomers and copolymers consisting of styrene monomers and other monomers (conjugated dienes, aliphatic unsaturated carboxylic acid esters, etc.), and any of these may be used as long as they contain styrene monomers. The styrene monomers referred to here are styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, ethylstyrene, pt-butylstyrene, etc., and styrene is preferred. Only one type of styrene monomer may be used, or two or more types may be used in combination. Specifically, examples include aromatic vinyl hydrocarbon-conjugated diene copolymers, mixed resins of aromatic vinyl hydrocarbon-conjugated diene copolymers and aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymers, and rubber-modified impact-resistant polystyrene. More specifically, examples include styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers, styrene-acrylic copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene copolymers, general-purpose polystyrene (GPPS), and highly branched polystyrene.

[0024] Examples of polyester resins include those obtained by condensation polymerization of a dicarboxylic acid component and a diol component. The type of dicarboxylic acid component is not particularly limited, and examples include terephthalic acid, o-phthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, decamethylenecarboxylic acid, their anhydrides, and lower alkyl esters. The types of diol components listed above are not particularly limited, and include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5- Examples include aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and polytetramethylene ether glycol; 2,2-bis(4-hydroxycyclohexyl)propane; alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane; and alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol.

[0025] Examples of polyolefin resins include polypropylene, polyethylene, and cyclic polyolefin resins. Examples of polypropylene resins include binary or ternary random copolymers with propylene as the main component and ethylene, butene, and α-olefin as copolymer components. Preferred α-olefins include ethylene, 1-butene, 1-hexene, and 1-octene, and may contain two or more types of α-olefins. Furthermore, the polypropylene resin may be a mixture of different propylene-α-olefin random copolymers. Examples of polyethylene resins include branched low-density polyethylene resins, linear low-density polyethylene resins, high-density polyethylene resins, ethylene-vinyl acetate copolymers, ionomer resins, or mixtures thereof. Also, copolymers of ethylene and α-olefins are included. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The above copolymers may be random copolymers or block copolymers. Examples of cyclic polyolefin resins include (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norbornene and its derivatives, or tetracyclododecene and its derivatives), (b) ring-opening polymers of the cyclic olefin or copolymers with α-olefins, (c) hydrogenated polymers of the polymers in (b), and (d) graft-modified products of (a) to (c) using unsaturated carboxylic acids and their derivatives. Examples of the cyclic olefins include norbornene, 6-methylnorbornene, 6-ethylnorbornene, 5-propylnorbornene, 6-n-butylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,6-dimethylnorbornene, 5-phenylnorbornene, and 5-benzylnorbornene.

[0026] Examples of polyamide resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of the above aliphatic polyamides include aliphatic nylon and its copolymers, specifically polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecanamide (nylon-11), polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sevacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,8), etc.

[0027] The types of resins contained in the first resin layer 11, the second resin layer 12, and the third resin layer 13 may be the same or different. Furthermore, the first resin layer 11, the second resin layer 12, and the third resin layer 13 may contain the same type of resin in different weight ratios. It is preferable that the first resin layer 11, which is an intermediate layer, and the second and third resin layers 12 and 13, which are surface layers, use different types of resins as their main components, as they have different roles to fulfill.

[0028] A preferred example of the main component resin contained in the first resin layer 11 is a polystyrene resin. Furthermore, preferred examples of the main component resins contained in the second resin layer 12 and the third resin layer 13 are polyester resins such as PET (Poly-Ethylene-Terephthalate).

[0029] The thickness of the first resin layer 11 is preferably 2 μm or more, and especially when the recycled film 1 is a heat-shrinkable film, it is preferably 10 μm or more, more preferably 12 μm or more, and even more preferably 15 μm or more. The thickness of the first resin layer 11 is preferably 40 μm or less, more preferably 30 μm or less, even more preferably 25 μm or less, and even more preferably 20 μm or less.

[0030] The thickness of the second resin layer 12 and the third resin layer 13 is preferably 1 μm or more, and more preferably 2 μm or more. The thickness of the second resin layer 12 and the third resin layer 13 is preferably 15 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and even more preferably 5 μm or less. The thicknesses of the second resin layer 12 and the third resin layer 13 may be the same or different.

[0031] The first resin layer 11 includes recycled resin material 3, which is made from a resin molded product 2 having a printed layer. The recycled resin material 3 is a recycled resin material containing printing-derived components, and may be a mechanically recycled material or a materially recycled material. The first resin layer 11 may further contain biomass material. The resin molded product 2 may be a product that has been used, an unused product, an intermediate processed product, leftovers, scraps, defective products, prototypes, discarded products, etc. In other words, the resin molded product 2 may be post-consumer material that has been collected after being distributed to the market and used by consumers, or it may be pre-consumer material that has not yet reached consumers. The resin molded product 2 is typically packaging material in the form of a film or label, but its form is not limited as long as it is a resin molded product having a printed layer. For example, the resin molded product 2 may be a container such as a tray, bottle, pouch, or bag for holding articles, or it may be an accessory for a container such as a cap. When the resin molded product 2 is a film or a label, the resin molded product 2 can be, for example, a printed film roll, a lead film for test printing, a film edge cut from a printed film, or a label collected after being distributed to the market. The printed layer is formed, for example, by using a gravure printing plate. The recycled resin raw material 3 may contain only one type of resin molded product 2 as a starting material, or it may contain multiple types of resin molded products 2.

[0032] The resin contained in the main body portion of the resin molded product 2, excluding the printed layer, may be of one type or multiple types. Preferably, the main body portion of the resin molded product 2, excluding the printed layer, contains at least one of the following: polystyrene resin, polyester resin, polyolefin resin, and polyamide resin. Details of the polystyrene resin, polyester resin, polyolefin resin, and polyamide resin in the resin molded product 2 are the same as those described for the resins contained in the first resin layer 11, the second resin layer 12, and the third resin layer 13. In addition, the main body portion of the resin molded product 2, excluding the printed layer, may contain additives. Examples of additives include antiblocking agents, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, and fluorescent whitening agents.

[0033] As an example of the resin molded product 2 described above, the following film selvage can be exemplified. Hereafter, the film selvage will also be denoted by reference numeral 2. The film selvage 2 is a narrow, elongated waste film, cut from the wide, elongated product film 5 shown in Figure 2. As shown in Figure 2, the product film 5 includes a product section 50 and film selvages 2,2 adjacent to both ends of the product section 50 in the width direction. Figure 2 shows the product film 5 in an unfolded state, but the product film 5 is wound up for storage and handling purposes and managed in the form of a roll. The product section 50 is used, for example, for packaging various containers such as plastic containers, glass containers, and paper containers. The film selvages 2,2 are separated from the product section 50 by cutting the product film 5 along the boundary line between the product section 50 and the film selvages 2,2 before the product section 50 is shipped. The product section 50 and the film selvages 2,2 are also wound up for storage and handling purposes and managed in the form of a roll.

[0034] Figure 3 shows a cross-sectional view of the product film 5. As shown in the figure, the product film 5, and the product portions 50 and film edges 2,2 cut from it, each have a resin film body 51 and a printed layer 52 laminated on the film body 51. In Figure 3, the printed layer 52 is laminated on only one side of the film body 51, but it may be laminated on both sides. The product portion 50 includes a printed layer 52 on which information such as the target product to be packaged by the product portion 50 is printed. The film edges 2,2 include a printed layer 52 on which information such as the printing status of the product portion 50 is printed.

[0035] Although not limited thereto, the product film 5, and the product portions 50 and film edges 2,2 cut therefrom, are, for example, heat-shrinkable films in their pre-heat-shrink state. The product film 5, product portions 50, and film edges 2 are uniaxially oriented films that shrink mainly in the TD (width direction) for use as a tubular label for the product portion 50. The heat shrinkage rate in the main shrinkage direction of the product film 5, product portions 50, and film edges 2 is appropriately selected considering the ease of attachment of the product portion 50 to containers, etc., when used as a label, but is preferably 30% or more, and more preferably 50% or more, when immersed in 90°C hot water for 10 seconds.

[0036] The first resin layer 11 may contain virgin resin raw materials and / or chemically recycled raw materials in addition to recycled resin raw materials 3. The types of resins in the recycled resin raw materials 3 and virgin resin raw materials contained in the first resin layer 11 are preferably the same, but may be different. Similarly, the types of resins in the recycled resin raw materials 3 and chemically recycled raw materials contained in the first resin layer 11 are preferably the same, but may be different. The ratio of recycled resin raw materials 3 to the total amount of virgin resin raw materials and chemically recycled raw materials contained in the first resin layer 11 (or the total amount of one of the raw materials if only one is included) is preferably 30 wt% or less, more preferably 15 wt% or less, even more preferably 10 wt% or less, and even more preferably 5 wt% or less. However, if the resin molded product 2 is deinked during the production of the recycled resin raw materials 3 to remove the printing layer to some extent, the ratio is preferably 5 wt% or more, and more preferably 10 wt% or more.

[0037] The second resin layer 12 and the third resin layer 13 preferably each contain at least one of virgin resin raw materials and recycled resin raw materials, and may also contain biomass raw materials. The recycled resin raw materials contained in the second resin layer 12 and / or the third resin layer 13 may be derived from a resin molded product 2 having a printed layer, or from a resin molded product without a printed layer, similar to the recycled resin raw material 3. The recycled resin raw materials contained in the second resin layer 12 and / or the third resin layer 13 may be mechanically recycled products or material recycled products, but are preferably chemically recycled products. Furthermore, when the second resin layer 12 and / or the third resin layer 13 contain both virgin resin raw materials and recycled resin raw materials, the types of resins of both raw materials are preferably the same, but may be different.

[0038] Through experiments relating to the embodiments described later, the inventors have discovered that when a multilayer recycled film is manufactured using recycled resin raw materials, the adhesion strength (interlaminar strength) between the layer containing the recycled resin raw materials and the adjacent layer may decrease. When interlaminar strength decreases, delamination between layers may occur more easily. The inventors have also discovered that the more printing-derived components are contained in the recycled film, the more likely the interlaminar strength of the recycled film is to decrease. In other words, the inventors have discovered that the interlaminar strength decreases due to the printing-derived components contained in the recycled resin raw materials. This is thought to be because the printing-derived components present at the interface between layers weaken the adhesive force between layers and cause interfacial fracture. Therefore, when manufacturing a multilayer recycled film using recycled resin raw materials containing printing-derived components, it is desirable to ensure a certain level of interlaminar strength by adjusting the amount of printing-derived components contained in the recycled film. Furthermore, the inventors have also discovered that even within the same single recycled film, variations in interlaminar strength can be observed depending on the location. This is thought to be because the printing-derived components are scattered at the interlayer interfaces, and while interlayer strength is maintained in areas where there are few printing-derived components, it decreases in areas where there are many printing-derived components.

[0039] From the above perspective, the average interlayer strength between the first resin layer 11 and the second resin layer 12 is preferably 0.85 N / 10 mm or more, and more preferably 0.9 N / 10 mm or more. When this numerical range is met, the interlayer strength of the recycled film 1 is ensured, and delamination between layers is appropriately prevented.

[0040] Similarly, the average interlayer strength between the first resin layer 11 and the third resin layer 13 is preferably 0.85 N / 10 mm or more, and more preferably 0.9 N / 10 mm or more. When this numerical range is met, the interlayer strength of the recycled film 1 is ensured, and delamination between layers is appropriately prevented.

[0041] The interlaminar strength of the film can be measured using the method described in the following examples. The average interlaminar strength is the average value of measurements taken when the interlaminar strength is measured multiple times using multiple samples cut from the same film. Although the interlaminar strength value varies depending on where the sample is cut, the average value converges to a single value as the number of measurements increases. The average interlaminar strength referred to here means this converged value and can be the average of at least four interlaminar strength measurements.

[0042] Incidentally, the printed layer contains various pigments (colorants). For example, the printed layer may contain inorganic pigments such as titanium dioxide (white pigment) and aluminum (silver pigment), and organic pigments such as carbon black (black pigment). Of these, titanium dioxide, which is a white pigment, is often used as an underlayer when printing colors other than white, and is a commonly used pigment when printing on resin molded products 2. Therefore, the amount of titanium contained in resin molded products 2 can roughly represent the amount of printing-derived components contained in resin molded products 2. Consequently, the amount of titanium contained in recycled film 1 can roughly represent the amount of resin molded products 2 with a printed layer used in the manufacture of recycled film 1.

[0043] Based on the above, the weight percentage of titanium contained in the recycled film 1 is preferably 0.1 ppm or more, more preferably 0.5 ppm or more, and even more preferably 1.0 ppm or more. When this numerical range is met, the recycled film 1 contains a certain amount or more of the resin molded product 2, and the resource recycling amount of the resin molded product 2 is ensured.

[0044] On the other hand, as described above, the more printing-derived components (titanium) contained in recycled film 1 there are, the lower the interlayer strength of recycled film 1 tends to be. From this perspective, the weight percentage of titanium contained in recycled film 1 is preferably 20.0 ppm or less, more preferably 18.0 ppm or less, even more preferably 15.0 ppm or less, and still more preferably 13.0 ppm or less. When this numerical range is met, the interlayer strength of recycled film 1 is further improved, and delamination between layers is more effectively prevented.

[0045] [2. Method for manufacturing recycled film] Figure 4 is a schematic diagram of the resource recycling system S1 for manufacturing recycled film 1. As shown in Figure 4, in the resource recycling system S1, the resin molded product 2 is recycled and recycled film 1 is manufactured as a new film.

[0046] The resource recycling system S1 comprises a manufacturing apparatus 20 for recycled resin raw material 3 and a film manufacturing apparatus 30. In the resource recycling system S1, recycled resin raw material 3 is manufactured from resin molded products 2 using the manufacturing apparatus 20. The manufacturing apparatus 20 is a device that manufactures recycled resin raw material 3 using resin molded products 2 as the starting material. Recycled resin raw material 3 is a resin raw material obtained by processing the resin molded products 2 into a shape that is easy to handle when manufacturing recycled film 1 from the resin molded products 2. Specifically, recycled resin raw material 3 can be in the form of fluff 3a, pellets 3b, powder 3c, granules 3d, etc. There is a type of pellet 3b that is manufactured by heating and melting the raw material and then solidifying it, but granules 3d are different from such types of pellets 3b; they are lumps that are compressed and solidified without heating and melting the powdered raw material. Granules 3d are typically opaque lumps. Furthermore, recycled resin raw materials 3, such as fluff 3a, powder 3c, or granules 3d, which are manufactured without heating and melting the raw materials, may be more susceptible to thermal degradation than recycled resin raw materials 3, such as the pellets 3b described above, which are manufactured by heating and melting the raw materials and then solidifying them, because they do not undergo excessive thermal history such as heating and melting during processing.

[0047] The resin molded product 2 can be processed into fluff 3a by, for example, using a known crusher, shredder, cutter, etc., to break the resin molded product 2 into small pieces. The size (area) of the fluff 3a is 500 mm². 2 The following is preferable: 300mm 2 The following is more preferable: 200mm 2 The following is even more preferable: 100 mm 2 The following are particularly preferable.

[0048] The resin molded product 2 can be processed into pellets 3b using, for example, a known resin pellet manufacturing machine. For example, fluff 3a can be supplied to an extruder, heated and melted in the extruder, then extruded through a die, and the extruded material can be cut into an appropriate shape to produce pellets 3b. Note that pellets 3b may be manufactured using not only the resin molded product 2 (fluff 3a) but also virgin resin raw material. In this case, virgin resin raw material is supplied to the extruder in addition to fluff 3a. This method yields pellets 3b of a type created by heating, melting, and then solidifying the raw material.

[0049] Another method for processing into pellets 3b is as follows: Film selvages 2 are unwound from a roll, and a single film selvage 2 or a bundle of multiple film selvages 2 is twisted by rotating it parallel to the conveying direction. After the twisted film selvages 2 are compressed, they are cut to a predetermined size. In this method, pellets 3b are produced without heating and melting the raw material.

[0050] The resin molded product 2 can be processed into powder 3c by, for example, the following method. First, the fluff 3a is immersed in a suitable solvent to dissolve the resin components contained in the fluff 3a in the solvent, thereby generating a solution containing the resin components. Then, the resin components are precipitated by cooling the solution, mixing a poor solvent into the solution, and / or heating the solution to evaporate the solvent. After that, the precipitated resin components is dried to produce powder 3c.

[0051] The resin molded product 2 can be processed into granules 3d, for example, by drying the resin component precipitates described above while stirring them under vacuum. Alternatively, the granules 3d can also be manufactured using a known granulator. In this case, the resin component precipitates or powder 3c described above can be fed into the granulator. In this case, it is preferable to dry the resin component precipitates or powder 3c before or during granulation, or to dry the granules 3d after granulation.

[0052] Furthermore, when manufacturing the recycled resin raw material 3, the printed layer contained in the resin molded product 2 may be removed to some extent by a known deinking method. That is, the recycled resin raw material 3 may be manufactured from a resin molded product 2 in which part of the printed layer has been removed and part of it remains. As a deinking method, for example, the resin molded product 2 may be immersed in a cleaning solution containing a solvent that can dissolve the printed layer. Alternatively, the printed layer may be physically removed from the resin molded product 2 using a blade, polishing roller, file, metal rotating brush, rotating blade, scraper, belt sander, blasting device (including wet blasting device), etc.

[0053] In the resource recycling system S1, recycled film 1 is further manufactured from recycled resin raw material 3 using film manufacturing equipment 30. Film manufacturing equipment 30 is a device that manufactures recycled film 1 using recycled resin raw material 3 manufactured using manufacturing equipment 20. Known film formation methods can be used as processing methods for recycled film 1.

[0054] Figure 5 shows an example of the configuration of the film manufacturing apparatus 30. In the example in Figure 5, the film manufacturing apparatus 30 comprises a T-die 300, cast rolls 310 and 320, a longitudinal stretcher 41, and a transverse stretcher 42. The T-die 300 comprises a T-die body 301 and raw material input sections 330, 331, and 332. Raw material for the second resin layer 12, which is one of the surface layers, is fed into the raw material input section 330. Raw material for the third resin layer 13, which is the other surface layer, is fed into the raw material input section 332. Recycled resin raw material 3, which is the raw material for the first resin layer 11, which is the intermediate layer, and other raw materials such as virgin resin raw material or chemically recycled raw material, if available, are fed into the raw material input section 331. Furthermore, if an adhesive layer is inserted between the first resin layer 11 and the second resin layer 12, and / or between the first resin layer 11 and the third resin layer 13, a separate raw material input section for the adhesive layer is provided, and the raw material for the adhesive layer is fed into it. The T-die body 301 heats and melts the raw materials supplied through the raw material input sections 330, 331, 332 (and, if applicable, the raw material input section for the adhesive layer), and then co-extrudes them to fuse the molten materials of the raw materials fed into each raw material input section together, thereby forming a single, integrated recycled film 1 (molten material). The cast rolls 310 and 320 cool the extruded molten material while sending it downstream.

[0055] Subsequently, the recycled film 1 is processed into a heat-shrinkable film by being stretched as appropriate to impart heat shrinkability. The longitudinal stretcher 41 stretches the recycled film 1, which has been cooled by the cast rolls 310 and 320, in the MD (medium-density) direction at a predetermined stretching ratio. The transverse stretcher 42 stretches the recycled film 1, which has been stretched in the MD (medium-density) direction, in the TD (two-stage) direction at a predetermined stretching ratio. The recycled film 1, which has undergone various stretching processes, is wound into a film roll.

[0056] Subsequently, functional layers may be appropriately laminated onto the recycled film 1. Functional layers include, for example, a printing layer, a matte layer, a protective layer (e.g., an overcoat layer, a hardcoat layer, etc.), a smoothing layer (e.g., an innercoat layer, an antiblocking layer, etc.), a barrier layer, a light-shielding layer, an ultraviolet-absorbing layer, a metal film, an easy-adhesion layer, a release layer, an antistatic layer, a conductive layer, and the like.

[0057] [3. Features] Since recycled film 1 is manufactured using recycled resin raw materials 3, it can contribute to resource recycling. Furthermore, although recycled film 1 contains printing-derived components that can cause delamination between layers, the amount of these components is adjusted to ensure a certain level of interlayer strength. Therefore, recycled film 1 that is less prone to delamination between layers is provided.

[0058] [4. Variant] Although one embodiment of the present invention 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 invention. For example, the following modifications are possible. Furthermore, the gist of the following modifications can be combined as appropriate.

[0059] [4-1] In the above embodiment, the first resin layer 11 is configured to contain recycled resin raw material 3. However, the intermediate layer, the first resin layer 11, may not contain recycled resin raw material 3, and at least one of the surface layers, the second resin layer 12 and the third resin layer 13, may contain recycled resin raw material 3.

[0060] [4-2] In the above embodiment, the recycled film 1 has a three-layer structure, but it may also have a two-layer structure or a multilayer structure of four or more layers. In this case as well, at least one of the layers contains the recycled resin raw material 3. [Examples]

[0061] The following describes embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0062] Recycled films according to Examples 1 and 2 and the Comparative Example shown in Table 1, as well as a film according to the Reference Example, were manufactured. All of these films had a three-layer structure, with surface layers (second and third resin layers) formed on both sides of the intermediate layer (first resin layer). However, the intermediate layer and the surface layers on both sides were bonded together with an adhesive layer mainly consisting of polyester elastomer. The thickness of all of these films was approximately 23 μm. More specifically, the thickness of the intermediate layer was approximately 17 μm, the thickness of each surface layer was approximately 3 μm, and the thickness of each adhesive layer was approximately 0.5 μm. All of these films were uniaxially oriented heat-shrinkable films with TD as the main shrinkage direction. All of these films were manufactured by feeding the raw materials for each layer shown in Table 1 in the weight ratios shown in Table 1 (the values ​​listed below the raw material names) into an extruder at a barrel temperature of 160°C to 200°C, co-extruding from a multi-layer die at 200°C, and cooling and solidifying on a cast roll at 50°C. Subsequently, the films were manufactured by stretching them to MD and TD, respectively. The stretching ratio for MD was set to approximately 140%, and the stretching ratio for TD was set to approximately 400%. In Table 1, "polyester resin" refers to virgin polyethylene terephthalate raw material, and "polystyrene resin" refers to virgin styrene-butadiene copolymer raw material. Also, in Table 1, "recycled resin raw material" refers to pellets manufactured from film selvages similar to film selvage 2 described in the above embodiment. The film body of the film selvage used here was a laminated film consisting of an intermediate layer made of styrene-butadiene copolymer with a thickness of approximately 17 μm, surface layers made of polyethylene terephthalate with a thickness of approximately 3 μm each, placed on both sides of the intermediate layer, and adhesive layers made mainly of polyester elastomer with a thickness of approximately 0.5 μm each, placed between the intermediate layer and the surface layers on both sides.

[0063] [Table 1]

[0064] The titanium content shown in Table 1 represents the weight percentage of titanium contained in the entire film. This titanium content was measured according to the measurement method described later. In addition, the thermal shrinkage rate, average interlaminar strength, and haze value were measured for each film related to the Reference Example, Examples 1 and 2, and Comparative Example, according to the measurement method described later.

[0065] <Method for measuring titanium content> Recycled resin raw material (pellets) was heated and decomposed with sulfuric acid and nitric acid, evaporated to dryness, and then nitric acid was added to dissolve the residue. The solution was then diluted to a fixed volume with pure water to obtain the test solution. Qualitative analysis of metal elements in the test solution was performed using inductively coupled plasma mass spectrometry (analytical instrument: Agilent 8900, manufactured by Agilent Technologies), and quantitative analysis of titanium (Ti) was performed to calculate the weight percentage of titanium contained in the recycled resin raw material. Subsequently, this weight percentage was converted to the weight percentage of titanium contained in the entire film based on the content of recycled resin raw material (pellets) contained in the entire film.

[0066] <Method for measuring thermal shrinkage rate> Samples measuring 100 mm in length (MD) x 100 mm in width (TD) were cut from each film relating to the Reference Example, Examples 1 and 2, and Comparative Example. Each sample was immersed in warm water at 70°C, 80°C, and boiling water (98°C) for 10 seconds. After removing the sample, the thermal shrinkage rate of MD was determined according to equation (1), and the thermal shrinkage rate of TD was determined according to equation (2). In equation (1), LMD is the length of MD of the sample after thermal shrinkage (mm), and in equation (2), LTD is the length of TD of the sample after thermal shrinkage (mm). The thermal shrinkage rate was measured using three samples, and the average value was calculated. Thermal shrinkage rate (%) = {(100-LMD) / 100} × 100···(1) Thermal shrinkage rate (%) = {(100-LTD) / 100} × 100···(2)

[0067] <Method for measuring average interlaminar strength> The interlaminar strength was measured in the direction perpendicular to the principal shrinkage direction (MD) according to a method conforming to JIS K6854. More specifically, samples measuring 100 mm in length (MD) and 10 mm in width (TD) were cut from each film relating to the Reference Example, Examples 1 and 2, and Comparative Example. A portion of the edge of each sample was delaminated between the intermediate layer and one of the surface layers in the direction perpendicular to the principal shrinkage direction (MD). Then, using a peel tester (Shinto Kagaku Co., Ltd., model number HEIDON TYPE:17 peel strength tester), the sample was pulled at a tensile speed of 200 mm / min in the direction perpendicular to the principal shrinkage direction (MD) and peeled in a 180° direction. The strength (N / 10 mm) at room temperature (23°C) was measured and defined as the interlaminar strength. The same measurement was performed four times for four samples, and the average value was defined as the average interlaminar strength. The evaluation criteria were as follows: an average interlaminar strength of 0.85 N / 10 mm or higher was considered "good (○)", and an average interlaminar strength of less than 0.85 N / 10 mm was considered "poor (×)". Figure 6 shows the results of four interlaminar strength measurements for each film related to the reference example, Examples 1 and 2, and the comparative example.

[0068] <Haze value> The haze value was measured using a haze meter (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.) at a temperature of 23°C, in accordance with JIS Z7136. The haze value was measured using four samples, and the average value was calculated.

[0069] <Consideration> The results in Table 1 show that the interlaminar strength of the film tends to decrease as the amount of printing-derived components (titanium) in the film increases. In other words, it was found that the interlaminar strength decreases due to the printing-derived components contained in the recycled resin raw material. Furthermore, the films in Examples 1 and 2 had an average interlaminar strength of 0.85 N / 10 mm or higher, and it was found that delamination between layers was suppressed more effectively than in the comparative example film, which had an average interlaminar strength of less than 0.85 N / 10 mm. It was also found that the weight percentage of titanium contained in the recycled film is preferably 20.0 ppm or less. [Explanation of Symbols]

[0070] 1. Recycled film 11 First resin layer 12 Second resin layer 13 Third resin layer 2. Resin molded product (film edge) 5 Product Film 50 Product Department 51 Film body 52 Printing layer 3 Recycled resin raw materials 3a Fluff 3b Pellet 3c powder 3d granules 20. Manufacturing equipment for recycled resin raw materials 30 Film manufacturing equipment 300 T-die 301 T-die body 310,320 Cast Roll 330,331,332 Raw material input section 41. Longitudinal extension machine 42 Lateral stretching machine S1 Resource Recycling System

Claims

1. The first resin layer and A second resin layer laminated on one side of the first resin layer and Equipped with, The first resin layer includes a recycled resin raw material made from a resin molded product having a printed layer, The average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more. The haze value is 14% or less. Recycled film.

2. Contains titanium in a weight percentage of 0.1 ppm to 20.0 ppm. The recycled film according to claim 1.

3. The aforementioned resin molded product includes at least one of polystyrene resin, polyester resin, polyolefin resin, and polyamide resin. The recycled film according to claim 1 or 2.

4. It is a heat-shrinkable film. The recycled film according to claim 1 or 2.

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