Recycled film

Abstract

Provided is a recycled film having a multilayer structure in which delamination is less likely to occur. This recycled film comprises a first resin layer and a second resin layer laminated on one surface of the first resin layer. The first resin layer contains a recycled resin raw material comprising a raw material constituted by a resin molded article having a printed layer. The weight ratio of titanium to the entire recycled film is 0.1-20.0 ppm. The average interlayer strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more. The recycled film has a haze value of 14% or less.

Description

Recycled film

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

[0002] In recent years, marine pollution caused by the disposal of plastics has become a global problem. 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 for producing recycled plastic (pellets) with less coloring, foreign matter, and bubbles after detaching a printing layer from a packaging material containing the printing layer.

[0003] Japanese Patent Application Laid-Open No. 2023-172449

[0004] By the way, when the present inventors produce 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 the 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.

[0006] Item 1. A recycled film comprising a first resin layer and a second resin layer laminated on one surface of the first resin layer, wherein the first resin layer contains a recycled resin raw material made from a resin molded product having a printing layer, the weight ratio of titanium in the entire recycled film is 0.1 ppm or more and 20.0 ppm or less, the average interlayer strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more, and the haze value is 14% or less.

[0007] Item 2. The recycled film according to Item 1, wherein the weight ratio of titanium with respect to the first resin layer is 0.1 ppm or more and 27.0 ppm or less.

[0008] Item 3. A recycled film comprising a first resin layer and a second resin layer laminated on one surface of the first resin layer, wherein the first resin layer contains recycled resin raw material made from a resin molded product having a printed layer, the weight ratio of titanium to the first resin layer is 0.1 ppm or more and 27.0 ppm or less, the average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more, and the haze value is 14% or less.

[0009] Item 4. The recycled film according to any one of items 1 to 3, wherein the resin molded product comprises at least one of polystyrene resin, polyester resin, polyolefin resin, and polyamide resin.

[0010] Item 5. A heat-shrinkable recycled film as described in any of items 1 to 4.

[0011] Item 6. Packaging labels manufactured from recycled films as described in any of Items 1 to 5.

[0012] Item 7. A recycled film comprising a first resin layer and a second resin layer laminated on one surface of the first resin layer, wherein the first resin layer contains a recycled resin 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, and the haze value is 14% or less.

[0013] According to the present invention, a recycled film with a multilayer structure that is resistant to delamination between layers is provided.

[0014] Cross-sectional view of recycled film according to one embodiment. Plan view of product film before the film edges are cut off according to one embodiment. Cross-sectional view of product film according to one embodiment. Block diagram schematically showing the resource recycling system according to one embodiment. Diagram showing the configuration of film manufacturing apparatus according to one embodiment. Graph showing the results of four interlayer strength measurements for each film according to the reference example, Examples 1 and 2, and comparative example.

[0015] The following describes a recycled film according to one embodiment of the present invention, with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals, and their descriptions are not repeated. Furthermore, each drawing is schematic, with parts omitted or exaggerated as appropriate, for ease of understanding.

[0016] [1. Composition of the Recycled Film] The recycled film 1 according to this embodiment is a packaging material in the form of a film or label that can be used in various fields such as food, beverages, pharmaceuticals, medical supplies, chemicals, cosmetics, toiletries, industrial products, and agricultural products. The recycled film 1 is used, for example, to package various containers such as plastic containers, glass containers, and paper containers.

[0017] When considering the above applications, 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 viewpoint of strength. From the viewpoint 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.

[0018] Furthermore, considering the above-mentioned applications, the haze value of 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, from the viewpoint of ensuring the transparency of recycled film 1.

[0019] The recycled film 1 is, for example, a heat-shrinkable film. In this case, the recycled film 1 shrinks when heated and is attached to the container by, for example, conforming to the outer surface of the container along its outer shape. The recycled film 1 is, for example, formed into a cylindrical shape, placed over the container so as to cover it from the outside, then heat-shrinked and attached to the container. The recycled film 1 is formed into a cylindrical shape by, for example, overlapping both ends of 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.

[0020] When considering the above applications, the recycled film 1 is preferably a uniaxially oriented film with TD as the main shrinkage direction. The stretching ratio of the recycled film 1 in the main shrinkage direction 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. Furthermore, the stretching ratio of the recycled film 1 in the direction perpendicular to the main shrinkage direction 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.

[0021] 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.

[0022] 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.

[0023] 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, and the like.

[0024] 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.

[0025] 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.

[0026] 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 resin containing a styrene monomer may be used. The styrene monomers referred to here are styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, ethylstyrene, p-t-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.

[0027] 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 mentioned 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; alicyclic diols such as 2,2-bis(4-hydroxycyclohexyl)propane, alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol.

[0028] 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 here 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 (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.

[0029] Examples of polyamide resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of aliphatic polyamides include aliphatic nylon and its copolymers, specifically polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (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), and polydecamethylene adipamide (nylon-10,8).

[0030] 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 require different roles.

[0031] Preferred examples of the main component resin contained in the first resin layer 11 include polystyrene resins and polyester resins such as PET (Poly-Ethylene-Terephthalate). Furthermore, preferred examples of the main component resins contained in the second resin layer 12 and the third resin layer 13 include polyester resins such as PET.

[0032] 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.

[0033] 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.

[0034] 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, a leftover product, a scrap, a defective product, a prototype, a discarded product, etc. In other words, the resin molded product 2 may be post-consumer material that has been collected after being distributed in 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 selvage 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.

[0035] 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.

[0036] As an example of the resin molded product 2 described above, a film selvage as shown below 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.

[0037] 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.

[0038] Although not limited thereto, the product film 5, and the product portion 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 portion 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 portion 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.

[0039] 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.

[0040] The second resin layer 12 and the third resin layer 13 preferably each contain at least one of virgin resin raw material and recycled resin raw material, and may also contain biomass raw material. The recycled resin raw material 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 material contained in the second resin layer 12 and / or the third resin layer 13 may be a mechanically recycled product or a materially recycled product, but is preferably a chemically recycled product. Furthermore, when the second resin layer 12 and / or the third resin layer 13 contains both virgin resin raw material and recycled resin raw material, the types of resins of both raw materials are preferably the same, but may be different.

[0041] According to the findings of the inventors through the experiments related to the embodiments described below, when producing a recycled film with a multilayer structure using a recycled resin raw material, the adhesion strength (interlayer strength) between the layer containing the recycled resin raw material included in the recycled film and the adjacent layer may decrease. When the interlayer strength decreases, delamination may easily occur between the layers. Further, the inventors also discovered that as the amount of the printing-derived components included in the recycled film increases, the interlayer strength of the recycled film tends to decrease. The inventors also discovered that as the amount of the printing-derived components included in the layer containing the recycled resin raw material increases, the interlayer strength of the recycled film tends to decrease. That is, the inventors discovered that the interlayer strength decreases due to the printing-derived components included in the recycled resin raw material. This is presumably because the printing-derived components present at the interface between the layers weaken the adhesive force between the layers and cause interfacial failure. Therefore, when producing a recycled film with a multilayer structure using a recycled resin raw material containing printing-derived components, it is desirable to ensure a certain interlayer strength by adjusting the amount of the printing-derived components included in the recycled film. Further, according to the findings of the inventors, even in the same single recycled film, variations in the interlayer strength can be observed depending on the location. This is presumably because the printing-derived components are scattered at the interface between the layers, and although the interlayer strength is ensured at locations where the printing-derived components are less present, the interlayer strength becomes low at locations where a large amount of the printing-derived components are present.

[0042] From the above viewpoints, 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 the numerical range is satisfied, the interlayer strength of the recycled film 1 is ensured, and delamination between the layers is appropriately prevented.

[0043] 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 the numerical range is satisfied, the interlayer strength of the recycled film 1 is ensured, and delamination between the layers is appropriately prevented.

[0044] Incidentally, the interlayer strength of the film can be measured by the method described in the following examples. The average interlayer strength is the average value of the measured values when the interlayer strength is measured multiple times using a plurality of samples cut out from the same film. Although the value of the interlayer strength varies depending on the location where the sample is cut out, the average value converges to one value as the number of measurements increases. The average interlayer strength referred to here means such a converged value and can be set as the average value of at least four measured values of the interlayer strength.

[0045] By the way, various pigments (colorants) are contained in the printing layer. For example, the printing layer may contain titanium oxide (white pigment), aluminum (silver pigment), etc. as inorganic pigments, and carbon black (black pigment), etc. as organic pigments. Among these, titanium oxide, which is a white pigment, is often used as an underlayer during printing of each color other than white and is a commonly used pigment when printing on the resin molded product 2. Therefore, the amount of titanium contained in the resin molded product 2 can generally represent the amount of components derived from printing contained in the resin molded product 2. Consequently, the amount of titanium contained in the recycled film 1 can generally represent the amount of the resin molded product 2 having the printing layer used in the production of the recycled film 1. Similarly, the amount of titanium contained in the first resin layer 11 can generally represent the amount of the resin molded product 2 having the printing layer used in the production of the first resin layer 11.

[0046] From the above, the weight ratio 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 the said numerical range is satisfied, it means that the recycled film 1 contains a certain amount or more of the resin molded product 2, and the amount of resource circulation of the resin molded product 2 is ensured.

[0047] On the other hand, as described above, the more printing-derived components (titanium) contained in the recycled film 1, the lower the interlayer strength of the recycled film 1 tends to be. From this viewpoint, the weight percentage of titanium contained in the 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 even more preferably 13.0 ppm or less. When this numerical range is met, the interlayer strength of the recycled film 1 is further improved, and delamination between layers is more effectively prevented.

[0048] The weight percentage of titanium contained in the first resin layer 11 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 first resin layer 11 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.

[0049] On the other hand, as described above, the greater the amount of printing-derived components (titanium) contained in the layer containing recycled resin raw materials (first resin layer 11), the lower the interlayer strength of the recycled film 1 tends to be. From this viewpoint, the weight percentage of titanium contained in the first resin layer 11 is preferably 27.0 ppm or less, more preferably 25.0 ppm or less, even more preferably 20.0 ppm or less, and even more preferably 17.0 ppm or less. When this numerical range is satisfied, the interlayer strength between the first resin layer 11 and the adjacent layer is further improved, and delamination between layers is more effectively prevented.

[0050] [2. Method for Manufacturing Recycled Film] Figure 4 is a schematic diagram of a 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.

[0051] 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 a resin molded product 2 using the manufacturing apparatus 20. The manufacturing apparatus 20 is a device that manufactures recycled resin raw material 3 using the resin molded product 2 as a starting material. Recycled resin raw material 3 is a resin raw material obtained by processing the resin molded product 2 into a shape that is easy to handle when manufacturing recycled film 1 from the resin molded product 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, can suppress thermal degradation compared to recycled resin raw materials 3, such as the pellets 3b of the type described above, which are manufactured by heating and melting the raw materials and then solidifying them, because they do not undergo excessive heat history such as heating and melting during processing.

[0052] 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.

[0053] 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.

[0054] Another method for processing into a different type of pellet 3b is as follows: The film selvage 2 is unwound from the winding body (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 selvage 2 is compressed, it is cut to a predetermined size. In this method, pellets 3b are produced without heating and melting the raw material.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] In the resource recycling system S1, recycled film 1 is further manufactured from recycled resin raw material 3 using film manufacturing apparatus 30. Film manufacturing apparatus 30 is an apparatus that manufactures recycled film 1 using recycled resin raw material 3 manufactured using manufacturing apparatus 20. Known film formation methods can be used as processing methods for recycled film 1.

[0059] 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.

[0060] 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 medium-density stretching (MD) direction at a predetermined stretching ratio. The transverse stretcher 42 stretches the recycled film 1, which has been stretched in the MD direction, in the horizontal stretching (TD) direction at a predetermined stretching ratio. The recycled film 1, which has undergone various stretching processes, is wound into a film roll.

[0061] 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.

[0062] Packaging labels can be manufactured from recycled film 1, which has functional layers appropriately laminated on it (typically, at least a printed layer with a design laminated on it). For example, an adhesive layer for attaching to the object to be packaged may be laminated on the recycled film 1. Alternatively, the recycled film 1 may be formed into a tubular shape so that it can cover the container to be packaged. In this case, for example, the recycled film 1 is formed into a tubular shape by overlapping both ends of the TD and sealing the overlapped portion to the MD. For example, the tubular recycled film 1 is placed over the container so as to cover the container from the outside, and then attached to the container. In this case, if the recycled film 1 is a heat-shrinkable film, it is attached to the container by being heat-shrinked.

[0063] [3. Features] Since the recycled film 1 is manufactured using recycled resin raw materials 3, it can contribute to resource recycling. In addition, although the recycled film 1 contains printing-derived components that cause delamination between layers, the amount is adjusted so that a certain level of interlayer strength is ensured. As a result, a recycled film 1 that is less prone to delamination between layers is provided.

[0064] [4. Modifications] 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.

[0065] [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.

[0066] [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.

[0067] The following describes embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0068] 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.

[0069]

[0070] Table 1 shows the weight percentage of titanium contained in the entire film and the weight percentage of titanium contained in the intermediate layer. The 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.

[0071] <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 the weight percentage of titanium (Ti) was calculated from the results of quantitative analysis. Subsequently, this weight percentage was converted to the weight percentage of titanium in the entire film based on the amount of recycled resin raw material (pellets) contained in the entire film. Furthermore, this weight percentage was converted to the weight percentage of titanium in the intermediate layer based on the amount of recycled resin raw material (pellets) contained in the intermediate layer.

[0072] <Method for Measuring Heat 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 heat shrinkage rate of MD was calculated according to the following formula (1), and the heat shrinkage rate of TD was calculated according to the following formula (2). In formula (1), LMD is the length of MD of the sample after heat shrinkage (mm), and in formula (2), LTD is the length of TD of the sample after heat shrinkage (mm). Note that the heat shrinkage rate was measured using three samples, and the average value was calculated. Heat shrinkage rate (%) = {(100-LMD) / 100} × 100 ... (1) Heat shrinkage rate (%) = {(100-LTD) / 100} × 100 ... (2)

[0073] <Method for Measuring Average Interlaminar Strength> The interlaminar strength was measured in the direction perpendicular to the principal shrinkage direction (MD) according to the method in accordance with JIS K6854. More specifically, samples of length (MD) 100 mm × width (TD) 10 mm 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.

[0074] <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 the method of JIS Z7136. The haze value was measured using four samples, and the average value was calculated.

[0075] <Discussion> From the results in Table 1, it was found that the interlaminar strength of the film tends to decrease as the amount of printing-derived components (titanium) contained 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 of Examples 1 and 2 had an average interlaminar strength of 0.85 N / 10 mm or more, 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. Furthermore, it was found that the weight percentage of titanium contained in the intermediate layer (first resin layer) is preferably 27.0 ppm or less.

[0076] 1 Recycled film 11 First resin layer 12 Second resin layer 13 Third resin layer 2 Resin molded product (film selvage) 5 Product film 50 Product section 51 Film body 52 Printed layer 3 Recycled resin raw materials 3a Fluff 3b Pellets 3c Powder 3d Granules 20 Recycled resin raw material manufacturing equipment 30 Film manufacturing equipment 300 T-die 301 T-die body 310, 320 Cast rolls 330, 331, 332 Raw material input section 41 Longitudinal stretcher 42 Transverse stretcher S1 Resource recycling system

Claims

1. A recycled film comprising a first resin layer and a second resin layer laminated on one surface of the first resin layer, wherein the first resin layer contains recycled resin raw material made from a resin molded product having a printed layer, the weight ratio of titanium to the entire recycled film is 0.1 ppm or more and 20.0 ppm or less, the average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more, and the haze value is 14% or less.

2. The recycled film according to claim 1, wherein the weight ratio of titanium to the first resin layer is 0.1 ppm or more and 27.0 ppm or less.

3. A recycled film comprising a first resin layer and a second resin layer laminated on one side of the first resin layer, wherein the first resin layer contains recycled resin raw material made from a resin molded product having a printed layer, the weight ratio of titanium to the first resin layer is 0.1 ppm or more and 27.0 ppm or less, the average interlaminar strength between the first resin layer and the second resin layer is 0.85 N / 10 mm or more, and the haze value is 14% or less.

4. The recycled film according to any one of claims 1 to 3, wherein the resin molded product comprises at least one of polystyrene resin, polyester resin, polyolefin resin, and polyamide resin.

5. A recyclable film according to any one of claims 1 to 3, which is a heat-shrinkable film.

6. A packaging label manufactured from the recycled film described in any one of claims 1 to 3.

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