Laminated material separation method and laminated material separation agent

Abstract

To provide a laminated material separation method and a laminated material separation agent that enable the easy separation of nylon from a laminate made up of a film containing nylon and at least one film containing a non-nylon polymer.SOLUTION: A laminated material separation method involves exposing a laminate made up of a film containing nylon and at least one film containing a non-nylon polymer to a liquid mixture containing a nylon-soluble solvent and chloroform or hexane.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for separating a layered material and a layered material separating agent. [Background technology]

[0002] Nylon, a type of polyamide, is widely used in fibers and plastics due to its toughness and excellent heat and chemical resistance. In 2020, 8.9 million tons of nylon were produced annually worldwide. Nylon is highly durable and does not decompose in nature, and there is no established method for recycling it. For this reason, nylon is incinerated or landfilled after use, which places a heavy burden on the environment.

[0003] One of the reasons why no recycling method for nylon has been established is that in many products that use nylon, nylon is used as a composite material to suppress product deterioration. For example, pouch containers used as containers for refillable detergents and the like are formed from a laminate consisting of a film containing nylon and at least one film containing a polymer other than nylon, such as polypropylene (PP) or polyethylene (PE). In order to recycle nylon from pouch containers, it is necessary to separate the various materials that make up the laminate, such as nylon.

[0004] Non-Patent Document 1 reports that in order to separate and recover carbon fibers from a carbon fiber reinforced composite material containing nylon 6, the nylon 6 in the carbon fiber reinforced composite material was dissolved by ultrasonic treatment at room temperature and normal pressure using a selected nylon 6 solvent, and the carbon fibers were separated and recovered. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Daisuke Sakamoto and 4 others, "Recycling of Carbon Fiber Reinforced Nylon Composites Using Solvents," Saitama Prefectural Industrial Technology Center, Research Report 2017, Vol. 16 (2018), pp. 18-22 Summary of the Invention [Problem to be solved by the invention]

[0006] As reported in Non-Patent Document 1, when an attempt was made to separate nylon from a commercially available pouch container using benzyl alcohol to which hydrochloric acid had been added, the printed substrate remained attached and could not be completely separated. If the printed substrate remains, the purity of the nylon decreases, which is inconvenient for the reuse of nylon.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a laminate material separation method and a laminate material separating agent that can easily separate nylon from a laminate comprising a film containing nylon and at least one film containing a polymer other than nylon. [Means for solving the problem]

[0008] (Laminated material separation method) The stacked material separation method described herein comprises: The method includes exposing a laminate having a nylon-containing film and at least one film containing a polymer other than nylon to a mixture containing a solvent in which nylon is soluble and chloroform or hexane.

[0009] The volume ratio of the solvent to the chloroform or hexane in the mixed solution is The ratio may be 1:3 to 1:15.

[0010] The stacked material separation method described herein comprises: The method includes heating a solvent in which nylon is soluble, in which a laminate formed by laminating a film containing nylon and at least one film containing a polymer other than nylon is immersed.

[0011] The temperature of the heated solvent may be 50 to 90°C.

[0012] The solvent may be 2,2,2-trifluoroethanol.

[0013] The polymer may be polyethylene.

[0014] (Laminated material separation agent) The laminated material separation agent described herein comprises: A mixture containing a nylon-soluble solvent and chloroform or hexane is included, Used to separate laminated materials from a stack.

[0015] The laminate comprises: The film may be a laminate in which a film containing nylon is laminated with at least one film containing a polymer other than nylon. Effect of the Invention

[0016] According to the present invention, nylon can be easily separated from a laminate in which a film containing nylon and at least one film containing a polymer other than nylon are laminated. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1A is a diagram showing nylon and PE separated in Example 1. FIG. 1B is a diagram showing a printing substrate separated in Example 1. [Diagram 2] FIG. 2 is a diagram showing the results of composition analysis by enzymatic degradation of nylon separated in Example 1. [Diagram 3] FIG. 13 shows the separated PE, printing substrate, and solution in which nylon is dissolved in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments and drawings. Note that in the following embodiments, the expressions "have", "include" and "contain" also include the meaning of "consisting of" or "consisting of".

[0019] (Embodiment 1) The method for separating a laminated material according to the present embodiment includes exposing a laminate in which a plurality of types of films are laminated as a laminated material to a mixed liquid containing a solvent in which nylon is soluble and chloroform or hexane. More specifically, the laminate is a laminate in which a film containing nylon and at least one film containing a polymer other than nylon are laminated. The nylon is not particularly limited, and examples thereof include nylon 4, nylon 6, nylon 11, nylon 12, nylon 6,6, nylon 6,10, nylon 6,12, nylon 4,6, nylon 6T, nylon 6I, nylon M5T nylon 6i, nylon 6i-11, etc.

[0020] Examples of polymers other than nylon include PP, PE, oriented polypropylene (OPP), polyethylene terephthalate (PET), biaxially oriented PET, ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), ethylene-vinyl acetate copolymer (EVA), low-density polyethylene (LDPE), linear low-density PE (LLDPE), non-oriented polypropylene (CPP), PVDC-coated OPP (KOP), and polyvinyl alcohol (PVA).

[0021] The laminate is, for example, the base material of a pouch container. When the base material of a pouch container is a laminate, the laminate may include a heat seal layer (sealant) and a printing base material as a polymer other than nylon. Examples of the basic configuration of the base material of a pouch container include a printing base material and a sealant; a printing base material, a gas barrier material, and a sealant; a printing base material and a gas barrier material and a sealant; a printing base material, a reinforcing material, a gas barrier material, and a sealant. As the printing base material, biaxially oriented PET, OPP, etc. are used. As the sealant, LDPE, LLDPE, EVA, etc. are used. As the gas barrier material, EVOH, PVDC, etc. are used. As the printing base material and gas barrier material, PVDC-coated PET, OPP, etc. are used. As the reinforcing material, PET, etc. are used. The above polymer in the laminate is preferably polyethylene.

[0022] Examples of the solvent in which nylon is soluble include 2,2,2-trifluoroethanol (TFE), hexafluoroisopropanol (HFIP), phenols, a saturated methanol solution of calcium chloride, concentrated formic acid, etc. As the solvent, TFE is preferable.

[0023] The volume ratio of the solvent to chloroform or hexane in the above mixed liquid (solvent:chloroform or hexane) is, for example, 1:3 to 1:15, 1:5 to 1:12, or 1:7 to 1:10.

[0024] In exposing the laminate to the mixed liquid, the laminate may be exposed to the mixed liquid so that the mixed liquid diffuses between the films. If the mixed liquid is in contact with the laminate, the mixed liquid penetrates between the films. Therefore, the mode of exposing the laminate to the mixed liquid is not particularly limited as long as at least the surface of the laminate is kept in contact with the mixed liquid. For example, when the laminate surface is a film containing nylon, the film surface containing nylon is exposed to the solution in the exposure step. In the exposure, the mixed liquid may be sprayed, dropped, or applied to the laminate. Preferably, in the exposure, the laminate is immersed in the mixed liquid. The mixed liquid may be mixed or stirred by inversion during immersion. In the case of inversion mixing or stirring, the rotation speed is not particularly limited, but is, for example, 10 to 80 rpm, 20 to 60 rpm, or 30 to 50 rpm.

[0025] The time for exposing the laminate to the mixed liquid is appropriately adjusted depending on the type of solvent in the mixed liquid used, the volume ratio of the solvent to chloroform or hexane, etc. The time for exposing the laminate to the mixed liquid is not limited, and is, for example, 3 to 24 hours, 4 to 18 hours, 8 to 16 hours, or 10 to 14 hours.

[0026] According to the laminate material separation method of the present embodiment, the film containing nylon and at least one film containing a polymer other than nylon can be separated simply by exposing the laminate to a mixed liquid. Thus, nylon can be easily separated from the laminate. When a film containing PE as a polymer other than nylon is contained in the laminate, PE can also be easily separated by the laminate material separation method of the present embodiment.

[0027] (Embodiment 2) The method for separating laminated materials according to the present embodiment includes heating the solvent in which the laminated body described above is immersed and in which nylon is soluble. The method for separating laminated materials according to the present embodiment will be described with a focus on the differences from the method for separating laminated materials according to the first embodiment. For points not specifically mentioned in the present embodiment, reference can be made to the first embodiment.

[0028] The temperature of the heated solvent is, for example, 50 to 90° C., 55 to 85° C., or 60 to 80° C. When TFE is used as the solvent, the temperature of the solvent is preferably 70 to 80° C.

[0029] The time for immersing the laminate in the solvent is appropriately adjusted depending on the type of solvent used, and is, for example, 1 to 5 hours, 1 to 4 hours, or 1 to 3 hours.

[0030] According to the laminated material separation method of the present embodiment, the difference in solubility in a solvent between nylon and polymers other than nylon in the laminate can be utilized to easily separate the nylon into a solution dissolved in a solvent and a film containing a polymer other than nylon. When a film containing PE as a polymer other than nylon is included in the laminate, the PE can also be easily separated by the laminated material separation method of the present embodiment.

[0031] In another embodiment, a layered material separating agent is provided for separating a layered material from a laminate. The layered material separating agent contains a mixture of a solvent in which nylon is soluble and chloroform or hexane. By exposing the laminate to the layered material separating agent, nylon and polymers other than nylon can be separated.

[0032] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. EXAMPLES

[0033] [Example 1] The base material of a pouch container (manufactured by Kao Corporation) was cut into a rectangular piece of 1 cm x 1 cm (approximately 1 g). The rectangular piece was immersed in a solvent consisting of a mixture of 9 mL chloroform and 1 mL TFE, and left to stand for approximately 12 hours. As a result, the rectangular piece separated into three types of film: a soft transparent nylon film, a hard transparent PE film, and a printing substrate. Figure 1(A) shows the nylon film and PE film. Figure 1(B) shows the printing substrate. The three materials could be separated from the base material of the pouch container simply by immersing it in the solvent.

[0034] The rectangular pieces were also separated when hexane was used instead of chloroform. On the other hand, when THF (tetrahydrofuran), ethyl acetate, and toluene were used instead of chloroform, separation was not observed. Separation was not observed when only chloroform or only hexane was used. When only TFE was used, the printing substrate was finely dispersed, making separation difficult.

[0035] 6.8 mL of 98% formic acid was added to 50 mg of the separated nylon, and the mixture was stirred for 168 hours while refluxing at 100°C. Distilled water was added to obtain a sample, which was then freeze-dried. The sample was suspended in Buffer A to a concentration of 10 mg / mL, and 200 μL of the suspension and 200 μL of the enzyme solution were added and the mixture was allowed to stand at 37°C.

[0036] The enzyme solutions were prepared so that the final concentrations of endo-type nylon hydrolase (hereinafter, GYAQ) and hexo-type nylon hydrolase (hereinafter, DNY) were 1.0 mg / mL. GYAQ is an enzyme with EC number 3.5.1.117 and a His-tag attached to the N-terminus. DNY is an enzyme with EC number 3.5.1.46 and a His-tag attached to the N-terminus.

[0037] After 24 hours of enzyme reaction, the sample was heated at 99°C for 10 minutes to stop the reaction, and then subjected to thin layer chromatography (TLC) analysis. 6-aminohexanoic acid (Ahx) monomer, Ahx dimer, and Ahx oligomer were used as standards in the TLC analysis.

[0038] Figure 2 shows the TLC plate, which confirmed that the nylon separated from the base material of the pouch container was nylon 6.

[0039] [Example 2] The rectangular piece was immersed in 10 mL TFE and kept at 75°C for approximately 2 hours. As a result, as shown in Figure 3, the rectangular piece separated into two types of films, namely, a hard transparent PE film and a rolled up print substrate. Some coloring was observed in the solution. When the TFE was removed from the solution, nylon precipitated. Immersion in the solvent and heating allowed the three materials to be separated from the substrate of the pouch container.

[0040] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the invention equivalent thereto are considered to be within the scope of the present invention. [Industrial Applicability]

[0041] The present invention is suitable for recycling nylon in a laminate in which a film containing nylon is laminated with at least one film containing a polymer other than nylon.

Claims

1. The method includes exposing a laminate having a nylon-containing film and at least one film containing a polymer other than nylon to a mixture containing a nylon-soluble solvent and chloroform or hexane. Laminated material separation method.

2. The volume ratio of the solvent to the chloroform or hexane in the mixed solution is The ratio is 1:3 to 1:

15. The method for separating laminated material according to claim 1 .

3. A method for producing a nylon-soluble solvent comprising: heating a nylon-soluble solvent in which a laminate of a nylon-containing film and at least one film containing a polymer other than nylon is immersed; Laminated material separation method.

4. The temperature of the heated solvent is 50 to 90° C. The method for separating laminated material according to claim 3.

5. The solvent is 2,2,2-trifluoroethanol; The method for separating a laminated material according to any one of claims 1 to 4.

6. the polymer is polyethylene; The method for separating a laminated material according to any one of claims 1 to 4.

7. A mixture containing a nylon-soluble solvent and chloroform or hexane is included, Used for separating laminated materials from stacks, Layered material separation agent.

8. The laminate comprises: A laminate in which a film containing nylon and at least one film containing a polymer other than nylon are laminated. The laminated material separating agent according to claim 7.

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