Recovery methods for cyclic olefin resins

Abstract

The method for recovering cyclic olefin resin of the present invention comprises: a first step, wherein a composite material containing at least a cyclic olefin resin and an isoresin different from the cyclic olefin resin is dissolved in a solvent capable of dissolving the cyclic olefin resin to generate a solution, thereby precipitating the isoresin component containing the isoresin; a second step, wherein the solution is filtered and the isoresin component is removed to obtain a filtrate; and a third step, wherein a composition containing the cyclic olefin resin is obtained from the filtrate.

Description

Technical Field

[0001] This invention relates to a method for recycling cyclic olefin resins. Prior Technology

[0002] In recent years, based on the requirements for the regeneration of resin materials, a method for recovering cyclic olefin resins from molded cyclic olefin resins, as described in Patent Document 1, has been proposed. Specifically, Patent Document 1 discloses a reuse method in which a cyclic olefin resin molded body is melted together with an antioxidant having a melting point of 100°C or higher and then mixed, thereby reshaping the resulting resin composition. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2008-222826 Summary of the Invention

[0004] [The problem that the invention aims to solve]

[0005] However, in the above method, a melting step must be performed before obtaining recycled products, which requires melting-related equipment.

[0006] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a method for recovering cyclic olefin resins from composite materials containing cyclic olefin resins and other different resins without the need for melting as a prerequisite for separation. [Technical means to solve the problem]

[0007] Item 1. A method for recycling cyclic olefin resins, comprising: The first step involves dissolving a film containing at least a cyclic olefin resin and a different resin in a solvent capable of dissolving the cyclic olefin resin to generate a solution, thereby precipitating the different resin component containing the different resin. The second step involves filtering the solution and removing the foreign resin components to obtain a filtrate. Step 3 involves obtaining a composition containing the aforementioned cyclic olefin resin from the filtrate.

[0008] Item 2. The method for recycling cyclic olefin resin as described in Item 1, wherein, in the first step above, the membrane is cut to a specified size and then dissolved in the solvent.

[0009] Item 3. The method for recycling cyclic olefin resins as described in Item 1 or 2 further includes a fourth step of forming a regenerated membrane by melting and granulating the aforementioned components.

[0010] Item 4. The method for recovering cyclic olefin resins as described in any one of Items 1 to 3, wherein the solvent contains at least one of aromatic solvents, cyclic terpene solvents, cyclic ether solvents and cyclic aliphatic solvents.

[0011] Item 5. A method for recycling cyclic olefin resins as described in any one of Items 1 to 4, wherein at least one of the aforementioned isomeric resins isopropylene resins, ethylene resins, polyester resins, and polyamide resins is present.

[0012] Item 6. A method for recovering cyclic olefin resins as described in any one of items 1 to 5, wherein, in step 1 above, the temperature of the solution is heated to 25°C or higher.

[0013] Item 7. A method for recovering cyclic olefin resins as described in any of Items 1 to 6, wherein, In step 3 above, a composition comprising the above-mentioned cyclic olefin resin is obtained by any of the following methods: The first method involves evaporating the solvent from the filtrate. The second method involves precipitating the composition containing the cyclic olefin resin by diluting the filtrate; or The third method involves precipitating the composition containing the cyclic olefin resin by cooling the filtrate.

[0014] Item 8. A method for recycling cyclic olefin resins as described in any one of items 1 to 7, wherein the composite material is formed from a membrane, the membrane having at least a first layer containing the cyclic olefin resin and a second layer containing the isomeric resin.

[0015] Item 9. The method for recycling cyclic olefin resins as described in Item 8, wherein at least one of the first layer and the second layer contains at least one of petroleum resin and additives.

[0016] Item 10. Includes: the step of recovering the cyclic olefin resin by means of the cyclic olefin resin recovery method described in Item 1 or 2; and the step of using the recovered cyclic olefin resin to manufacture a heat-shrinkable film. [Effects of the Invention]

[0017] According to the present invention, cyclic olefin resins can be recovered from composite materials containing cyclic olefin resins and other different resins without the need for melting as a prerequisite for separation. Simple Explanation of the Diagram

[0018] [Figure 1] is a cross-sectional view showing one example of a membrane as an object. [Figure 2] is a flowchart of a method for recycling cyclic olefin resin according to an embodiment of the present invention. Implementation

[0019] The following describes one embodiment of the method for recovering cyclic olefin resins according to the present invention. In this embodiment, a method for recovering cyclic olefin resins from a membrane containing cyclic olefin resins will be described. First, the membrane to be described will be described, and then the separation method will be described.

[0020] <1. Example of a film containing a cyclic olefin resin> There are various types of membranes that can be used in this embodiment, such as membranes containing cyclic olefin resins and other resins. For example, a membrane obtained by removing ink from commercially recycled membranes can be used as an example. Furthermore, the cyclic olefin resin can be separated and recovered from such membranes using the technology of this invention.

[0021] <1-1. Cyclic Olefin Resins> Examples of cyclic olefin resins include: (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norcamphene and its derivatives or tetracyclododecene and its derivatives); (b) ring-opening polymers of the cyclic olefins or copolymers with α-olefins; (c) hydrides of the polymers in (b); and (d) graft-modified products of (a) to (c) formed using unsaturated carboxylic acids and their derivatives.

[0022] The cyclic olefins mentioned above are not particularly limited, but examples include: nobornene, 6-methylnobornene, 6-ethylnobornene, 5-propylnobornene, 6-n-butylnobornene, 1-methylnobornene, 7-methylnobornene, 5,6-dimethylnobornene, 5-phenylnobornene, 5-benzylnobornene, etc.

[0023] Furthermore, examples of tetracyclic dodecene and its derivatives include 8-methyltetracyclo-3-dodecene, 8-ethyltetracyclo-3-dodecene, and 5,10-dimethyltetracyclo-3-dodecene.

[0024] <1-2. Isoresin> Examples of isoresins that are separated from self-cyclic olefin resins include at least one of propylene resins, ethylene resins, polyester resins, and polyamide resins.

[0025] Examples of propylene-based resins include binary or ternary random copolymers with propylene as the main component and ethylene, butene, and α-olefins as copolymerizing components. Specifically, the α-olefins are preferably composed of ethylene, 1-butene, 1-hexene, 1-octene, etc., and may also contain two or more α-olefins. Furthermore, propylene-based resins may also be mixtures of different propylene-α-olefin random copolymers.

[0026] Examples of ethylene-based resins include: branched low-density polyethylene resin or linear low-density polyethylene resin, ethylene-vinyl acetate copolymer, ionomer resin, or mixtures thereof. Also, copolymers of ethylene and α-olefins can be listed. Examples of α-olefins include: 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc.

[0027] The copolymers mentioned above can be random copolymers or block copolymers.

[0028] Polyester resins include, for example, those obtained by polycondensation of dicarboxylic acid and diol.

[0029] As a dicarboxylic acid, there are no particular limitations. Examples include: phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itconic acid, decamethylcarboxylic acid, and their anhydrides and lower alkyl esters.

[0030] As a diol, there are no particular limitations. Examples include: ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylenediol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentanediol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and other aliphatic diols; epoxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane and 2,2-bis(4-hydroxycyclohexyl)propane; 1,4-cyclohexanediol; 1,4-cyclohexanediol, 1,4-cyclohexanediol, and other alicyclic diols.

[0031] Examples of polyamide resins include aliphatic polyamides and aromatic polyamides. Examples of aliphatic polyamides include aliphatic nylons and their copolymers, specifically: polyhexamethylene amine (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecylamine (nylon-11), polylauryl lactam (nylon-12), polyhexamethylene glycol diamine (nylon-2,6), polyhexamethylene glycol diamine (nylon-4,6), polyhexamethylene glycol diamine (nylon-6,6), polyhexamethylene glycol diamine (nylon-6,10), polyhexamethylene glycol didodecane (nylon-6,12), polyhexamethylene glycol dioctyl glycol diamine (nylon-8,6), and polyhexamethylene glycol dioctyl glycol diamine (nylon-10,8), etc.

[0032] <1-3. Resins and additives separated together with cyclic olefin resins> The recycled cyclic olefin resins may be mixed with resins (hereinafter sometimes referred to as mixed resins) or additives to a degree that does not affect transparency. Examples of such resins include petroleum resins, terpene resins, rosin resins, and benzofuran-indene resins. Examples of petroleum resins include alicyclic petroleum resins derived from cyclopentadiene or its dimers, or aromatic petroleum resins derived from C9 compounds. Examples of additives include heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, and fluorescent whitening agents; additives derived from organic compounds are particularly noteworthy.

[0033] This resin or additive, along with the cyclic olefin resin, is dissolved in the solvent described below and separated and recovered as a mixture with the cyclic olefin resin. However, since the solubility of the aforementioned resin or additive may vary depending on the type of solvent selected in this technology, it may not necessarily be mixed with the cyclic olefin resin and thus separated. Therefore, sometimes, depending on the additive, it is separated and recovered as a mixture with a different resin. Additives that are separated from a mixture of different resins include those that are insoluble in the solvents described below at room temperature, particularly inorganic additives or additives derived from crosslinking resins.

[0034] <1-4. Other Examples of Membranes> Regarding the membrane, besides the single-layer membrane containing a mixture of cyclic olefin resin and a different resin as described above, it can also be a membrane with multiple layers. For example, the membrane shown in Figure 1 has layers 11, 12, and 13 stacked sequentially. Layers 11 and 13 are, for example, layers containing a mixture of cyclic olefin resin, petroleum resin (mixed resin), and polyethylene (different resin), while layer 2 is, for example, a layer containing a mixture of polypropylene (different resin) and petroleum resin. In this case, the composition containing the mixture of cyclic olefin resin and petroleum resin can be separated from the membrane according to the following method.

[0035] Furthermore, the membrane in Figure 1 is only one example; it can also be a membrane with two or four or more layers. And it is sufficient that at least one layer contains at least a cyclic olefin resin, and the other layers contain an isomeric resin. Alternatively, at least one layer may contain a mixture of a cyclic olefin resin and an isomeric resin. It is also not necessary to mix petroleum resin or other mixed resins or additives, but when petroleum resin or other mixed resins or additives are mixed, it can be prepared by mixing with at least one of the cyclic olefin resin and the isomeric resin.

[0036] <2. Separation Methods for Cyclic Olefin Resins> Next, a method for separating cyclic olefin resins from the membrane described above will be explained. The separation method includes the following five steps: (1) Membrane cutting steps (2) Membrane dissolution step (step 1) (3) Filtering step (step 2) (4) Separation steps of cyclic olefin resins (step 3) The following is a detailed explanation of each step.

[0037] <2-1. Membrane Cutting Steps> First, the membrane is cut to a specified size. This increases the contact area between the cut membrane and the solvent, making it easier to dissolve. There is no particular limitation on the size; for example, it can be cut to a size of 0.1–4 cm square, preferably 0.2–2 cm square. However, this step is not mandatory, and the membrane can be directly immersed in the solvent in the next step without being cut.

[0038] <2-2. Membrane Dissolution Steps> Next, the membrane cut as described above is dissolved in a solvent to form a solution. The solvent used here is one that can dissolve cyclic olefin resins and is not a solvent that dissolves other resins. For example, as long as it does not affect the transparency of the recycled cyclic olefin resin, it can also be a solvent that dissolves a small amount of other resins. Furthermore, it can also be a solvent that can dissolve the above-mentioned mixed resins or additives.

[0039] The solvent can be appropriately selected according to the type of cyclic olefin resin to be separated. For example, a solvent containing at least one of aromatic solvents, cyclic terpene solvents, cyclic ether solvents, and cyclic aliphatic solvents can be selected.

[0040] Examples of aromatic solvents include xylene, toluene, benzene, and 1,3,5-trimethylbenzene. These can also dissolve mixed resins such as petroleum resins, or additives such as heat stabilizers.

[0041] Examples of solvents that can be used to dissolve cyclic terpenes include limonene and pinene. These can also dissolve mixed resins such as petroleum resins, or additives such as heat stabilizers.

[0042] Examples of cyclic ether solvents include tetrahydrofuran (THF) and 2-methyltetrahydrofuran. These can also dissolve mixed resins such as petroleum resins, or additives such as heat stabilizers.

[0043] Examples of cyclic aliphatic solvents include cyclohexane, methylcyclohexane, and ethylcyclohexane. These can also dissolve mixed resins such as petroleum resins, or additives such as heat stabilizers.

[0044] The cut membrane is dissolved in the solvent described above to form a solution. As mentioned above, the solvent can dissolve cyclic olefin resins but not foreign resins; therefore, in the solution, the foreign resin component containing the foreign resin precipitates.

[0045] At this point, the temperature of the solution is not particularly limited; it can be room temperature or a temperature higher than room temperature. The higher the temperature, the shorter the dissolution time, thus improving the efficiency of the separation process. For example, it is preferable to heat the solution to above 25°C, more preferably above 50°C, even more preferably above 70°C, and especially preferably above 90°C. However, it is necessary to heat the solution to a temperature below the boiling point of each solvent.

[0046] Since the dissolution time depends on the amount of solvent and film, there is no particular limitation. For example, it can be set to the time until the precipitation of the resin component can be clearly observed visually. When the solution is heated as described above, it can be set to about 5 to 60 minutes, more preferably about 10 to 30 minutes. On the other hand, when dissolving at room temperature, it can be set to 30 minutes or more, more preferably 60 minutes or more.

[0047] For example, according to the experiments conducted by the inventors, the dissolution of cyclic olefin resins can be confirmed at the following time. [Table 1] boiling point temperature Dissolution time xylene 139℃ 90℃ less than 20 minutes Toluene 110℃ 90℃ less than 10 minutes Limonene 176℃ 90℃ less than 30 minutes THF 66℃ 60℃ less than 30 minutes Cyclohexane 80℃ 60℃ less than 30 minutes xylene 139℃ room temperature less than 60 minutes Toluene 110℃ room temperature less than 60 minutes Limonene 176℃ room temperature 60 minutes or more THF 66℃ room temperature 60 minutes or more Cyclohexane 80℃ room temperature 60 minutes or more

[0048] Thus, after the prescribed dissolution time, the isoresin component containing the isoresin precipitates. Furthermore, in cases where the solution has been heated, after the aforementioned dissolution time, the solution is cooled to room temperature. As described above, although the isoresin may dissolve depending on the type of solvent, if the solution is cooled to room temperature, the dissolved isoresin can precipitate out, resulting in a precipitate.

[0049] <2-3 Filtering Steps> Next, the filtration step will be explained. In this step, the solution containing the precipitate as described above is filtered using a filter. The filter is not particularly limited as long as it can separate the precipitate; for example, a filter with a pore size of 100 μm or less can be used. Alternatively, vacuum filtration (suction filtration) can be used, where the filtrate is drawn into a vacuum vessel while filtration is performed. This can shorten the filtration time.

[0050] In this way, the isomeric resin components and the filtrate containing dissolved cyclic olefin resins can be separated. That is, the isomeric resin components can be recovered. The recovered isomeric resin components can be molded into molded articles, films, or sheets for reuse, depending on their physical properties and degree of degradation. Furthermore, appropriate processing can be carried out according to the degree of degradation, such as mixing the recovered isomeric resin components with the same or different types of original materials or additives such as heat stabilizers, thereby obtaining reusable recycled materials.

[0051] <2-4. Separation Steps for Cyclic Olefin Resins> Subsequently, the cyclic olefin resin is separated from the filtrate. There is no particular limitation on the separation method; various methods can be used. For example, the cyclic olefin resin can be separated by evaporating the solvent (Method 1). In this case, the temperature and time conditions depend on the type of solvent and are therefore not particularly limited. For example, the solvent can be evaporated by heating the filtrate at 50–200°C for 0.5–2 hours. Alternatively, vacuum distillation can be used, i.e., placing the filtrate in a vacuum vessel and removing the solvent by evaporation at a lower temperature range. This can shorten the separation time.

[0052] Alternatively, a poor solvent that cannot dissolve cyclic olefin resin can be added to the filtrate to precipitate the cyclic olefin resin, and then the liquid can be filtered to obtain the cyclic olefin resin (method 2). Examples of such poor solvents include alcohols, ketones, esters, and water.

[0053] Examples of alcohol-based solvents include lower alkyl alcohols having a single hydroxyl group, such as methanol, ethanol, propanol, isopropanol, and butanol. Examples of ketone-based solvents include acetone and methyl ethyl ketone. Examples of ester-based solvents include methyl acetate, ethyl acetate, propyl acetate, and butyl acetate.

[0054] Alternatively, the cyclic olefin resin can be precipitated by cooling the filtrate, and the cyclic olefin resin can be obtained by filtering the liquid (method 3). In this case, the temperature and time conditions depend on the type of solvent and are therefore not particularly limited. For example, the cyclic olefin resin precipitate can be generated by cooling the filtrate to -25 to 10°C and letting it stand for 0.5 to 2 hours.

[0055] When the cyclic olefin resin can be obtained from the filtrate in the manner described above, it is naturally dried or heated and dried for a specified time of, for example, about 1 to 3 days. To shorten the drying time, drying can be carried out under reduced pressure. In this way, the cyclic olefin resin can be separated from the membrane and recovered. Furthermore, the recovered cyclic olefin resin may contain the mixed resins or additives described above.

[0056] <2-5 Others> The cyclic olefin resin recovered in the above manner can be granulated by melting. Furthermore, the granules can be melted to form a film as needed. Alternatively, the recovered cyclic olefin resin can be melted directly to form a film. In this way, a film containing cyclic olefin resin can be obtained.

[0057] For example, a heat-shrinkable film containing a cyclic olefin resin can be manufactured. This heat-shrinkable film can be a single layer of cyclic olefin resin or multiple layers containing other resin layers besides the cyclic olefin resin. Examples of other resin layers include: cyclic olefin resins, polyethylene resins, polypropylene resins, petroleum resins, etc. Alternatively, it can be a raw material derived from petroleum or a raw material derived from biomass. Furthermore, it can be a recycled material. In this case, both chemical recycling and mechanical recycling are possible.

[0058] Furthermore, the layer formed from the recycled cyclic olefin resin can be a single layer or comprised of multiple layers, preferably containing 5% by weight or more of the manufactured heat-shrinkable film. The layer formed from the cyclic olefin resin may also contain anti-blocking agents and additives. Examples of additives include: heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, and fluorescent whitening agents. Moreover, the recycled cyclic olefin resin can be reused as raw material for the recycled membrane.

[0059] This type of heat-shrinkable film can be formed by successive biaxial stretching. Preferably, the longitudinal stretching ratio is set to 1 or more, and the transverse stretching ratio is set to 3 or more. Furthermore, the extrusion temperature is preferably 150°C to 250°C, and more preferably 160°C to 240°C. The transverse stretching can be set to 50°C to 120°C in the preheating zone, stretching zone, and heat-setting zone of the stretching machine during forming.

[0060] Furthermore, 5 to 100% by weight, more preferably 10 to 90% by weight, and even more preferably 20 to 80% by weight, of the cyclic olefin resin contained in the heat-shrinkable film can be made into the recycled cyclic olefin resin. Moreover, the inventors have confirmed that a heat-shrinkable film obtained with this content of recycled cyclic olefin resin can achieve the same physical properties as a heat-shrinkable film using the original material as the cyclic olefin resin.

[0061] <3. Characteristics> The following effects can be obtained by using the separation method for cyclic olefin resins as described above.

[0062] (1) Cyclic olefin resins can be separated and recovered from membranes containing cyclic olefin resins and other different resins without the need for melting as a prerequisite for separation.

[0063] (2) Heating the solvent can shorten the dissolution time, but dissolution can also be carried out without heating the solvent. Therefore, cyclic olefin resins can be separated without heating. In particular, if heating is repeated, there is a risk that the cyclic olefin resins will deteriorate and become discolored (there is a risk of reduced transparency), so the method of this embodiment has an advantage in this respect.

[0064] (3) Depending on the type of solvent, it can dissolve not only cyclic olefin resins but also mixed resins or additives. Therefore, the recovered cyclic olefin resins contain mixed resins or additives. Thus, for example, cyclic olefin resins with pre-added heat stabilizers or other additives can be recovered without the need to add such additives (or mixed resins) again, or the recovered cyclic olefin resins can be reused by adding a small amount.

[0065] (4) As shown in the following examples, the heat-shrinkable film obtained using the recovered cyclic olefin resin exhibits the same physical properties as the heat-shrinkable film obtained using the original cyclic olefin resin material. Therefore, it is believed that the cyclic olefin resin recovered by the above method exhibits the same properties as the original material.

[0066] Furthermore, although membranes were listed as the separation target in the above embodiments, the above method can also be applied to composite materials containing cyclic olefin resins and other resins, such as particles, in addition to membranes, thereby separating and recovering the cyclic olefin resins. In particular, when the volume fraction of the composite material is 51 v / v% or more of cyclic olefin resins, the above method can be used to separate and recover the cyclic olefin resins. [Example]

[0067] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to these embodiments.

[0068] <1. Membrane as an object> First, as shown in Table 2, a membrane containing a cyclic olefin resin is prepared as the object of the recycling method of the present invention. [Table 2] layer Composition (parts by weight) Layer thickness Level 1 Cyclic olefin resin (60 parts) + petroleum resin (15 parts) + ethylene resin (25 parts) 5.5 μm 2nd floor Acrylic resin (85 parts) + petroleum resin (15 parts) 29 μm 3rd floor Cyclic olefin resin (60 parts) + petroleum resin (15 parts) + ethylene resin (25 parts) 5.5 μm

[0069] <2. Recycling Methods> The steps shown in Figure 2 were performed on the above membrane. First, as a pulverization step, the membrane was pulverized into pieces of approximately 1 cm². Next, as a dissolution step, 3 g of the pulverized membrane was added to 120 ml of (±) limonene solvent, and the solution was heated to 90°C, while stirring until the membrane was completely dissolved. After heating and stirring for 30 minutes, heating was stopped, and the solution was cooled to room temperature while stirring. This resulted in a cloudy solution.

[0070] Next, as a filtration step, the solution that produces a white turbidity is filtered through a membrane filter (1 μm pore size) to separate the filtrate and the liquid. The filtrate is dried under reduced pressure to remove the solvent, yielding a colorless recovery 1. As a dilution and precipitation step, 100 ml of isopropanol is added while stirring the filtrate to dilute it, thereby producing a colorless precipitate. Next, as a filtration step, the solution containing the precipitate is filtered through a membrane filter (1 μm pore size) to separate the precipitate and the liquid. Finally, as a drying step, the precipitate is dried under reduced pressure to remove the solvent. Thus, a colorless recovery 2 is obtained.

[0071] <3. Analysis of Recovered Items (DSC Determination)> The DSC measurement data of recycled materials 1 and 2, cyclic olefin resins, petroleum resins, ethylene resins, and propylene resins are shown in Table 3 below. Furthermore, in this measurement, DSC (Differential Scanning Calorimetry) was used, and the measurements were performed according to JIS K 7122 (Transfer Heat Measurement). A DSC2910 [trade name, manufactured by TA Instruments Co., Ltd.] was used as the measuring apparatus. The measured values ​​recorded in Table 3 represent the endothermic peak temperature or the temperature at the intersection of the tangent at the reference line and the inflection point, measured at a heating rate of 10°C / min within the range of 40–200°C. [Table 3] object DSC measurement value (°C) Recycling 1 115.3, 134.5 Recyclable Item 2 75.3 Cyclic olefin resins 84.0 Petroleum resin 63.1 Ethylene resins 112.3 Acrylic resins 156.1

[0072] The measured values ​​of recovered product 1 were all found to be above 100°C, which is considered to be derived from the melting point peaks of ethylene-based and propylene-based resins. Furthermore, since no endothermic peaks or baseline shifts were observed below 100°C, it is believed that recovered product 1 does not contain components of cyclic olefin resins or petroleum resins that have glass transition temperatures below 100°C.

[0073] On the other hand, the endothermic peak of recoverable product 2 was found below 100°C, which is considered to be a peak originating from the glass transition temperature of cyclic olefin resins or petroleum resins. Furthermore, since no endothermic peak or baseline shift was observed above 100°C, it is believed that recoverable product 2 does not contain ethylene resins or propylene resins that have endothermic peaks above 100°C.

[0074] <4. Analysis of Recovered Items 2 (FT-IR Determination)> The FT-IR measurement data of Recycles 1 and 2, cyclic olefin resins, petroleum resins, ethylene resins, and propylene resins are shown in Table 4 below. Furthermore, the presence or absence of characteristic peaks that do not overlap in each resin component is summarized in Table 4. This measurement was performed using the ATR (Total Reflectance) method of a Fourier Transform Infrared Spectrophotometer (FT-IR). An FTIR Spectrum 100 [trade name, manufactured by PerkinElmer, Inc.] was used as the measuring apparatus. [Table 4] object FT-IR peak measurement (cm⁻¹) 2952 2852 1447 1376 718 Recycling 1 ○ ○ ○ Recyclable Item 2 ○ ○ Cyclic olefin resins ○ Petroleum resin ○ Ethylene resins ○ Acrylic resins ○ ○

[0075] Recovered material 1 showed a peak at 718 cm⁻¹, which is believed to originate from ethylene resin, and peaks at 2952 cm⁻¹ and 1376 cm⁻¹, which are believed to originate from propylene resin. Therefore, it is considered to be a mixture of ethylene resin and propylene resin.

[0076] Recovery 2 showed a peak at 2852 cm⁻¹, which is believed to be derived from cyclic olefin resins, and a peak at 1447 cm⁻¹, which is believed to be derived from petroleum resins. Therefore, it is considered to be a mixture of cyclic olefin resins and petroleum resins.

[0077] Based on the results of the DSC and FT-IR measurements described above, it can be concluded that recovered product 1 is a mixture of ethylene-based and propylene-based resins, and recovered product 2 is a mixture of cyclic olefin resins and petroleum resins. Therefore, it is evident that cyclic olefin resins can be recovered using the recovery method of the present invention.

[0078] <5. Manufacturing of heat-shrinkable films using recycled cyclic olefin resins> Subsequently, a heat-shrinkable film (hereinafter referred to as the recycled material film) using recycled material 2 as raw material was manufactured in the following order. For comparison, a heat-shrinkable film (hereinafter referred to as the original material film) using virgin material was also manufactured. Each film is a three-layer structure consisting of a surface layer with a total thickness of 50 μm on both surface layers of the core layer, and the thickness ratio of the surface layer / core layer / surface layer is set to 1 / 4 / 1. The raw materials are shown below. [Table 5] Original material membrane Recycled material membrane Core layer Polypropylene resin (70% by weight) Polyethylene resin (10% by weight) Petroleum resin (20% by weight) Polypropylene resin (70% by weight) Polyethylene resin (10% by weight) Petroleum resin (20% by weight) surface layer Cyclic olefin resin (80% by weight) Polyethylene resin (20% by weight) AB agent (0.1% by weight) Cyclic olefin resin (40% by weight) Polyethylene resin (20% by weight) AB agent (0.1% by weight) Recycling 2 (40% by weight) Content of Recycling Material 2 0% by weight 13.6% by weight

[0079] The material is fed into an extruder with a barrel temperature of 160-250°C and extruded into a three-layer sheet through a multi-layer die at 210°C. The sheet is then cooled and cured using a 30°C extraction roller. Subsequently, the sheet is stretched at a ratio of 6 in a stretching machine with a preheating zone of 105°C, a stretching zone of 89-91°C, and a heat-setting zone of 85°C. Finally, it is wound up using a winding machine to obtain a heat-shrinkable film with a machine direction (MD) orthogonal to the main shrinkage direction and a transverse direction (TD).

[0080] The following physical properties were determined for each heat-shrinkable film obtained.

[0081] <Heat Shrinkage Rate> The obtained heat-shrinkable film was cut into samples of size MD100 mm × TD100 mm to obtain test pieces. The obtained test pieces were immersed in warm water at 70℃, 80℃, and 90℃ and boiling water (100℃) for 10 seconds, and then removed and immersed in water at 15℃ for 5 seconds. The heat shrinkage rate in the MD direction was calculated according to the following formula (1), and the heat shrinkage rate in the TD direction was calculated according to the following formula (2). Furthermore, LMD in the following formula (1) is the length of the test piece in the MD direction after heat shrinkage, and LTD in the following formula (2) is the length of the test piece in the TD direction after heat shrinkage. The heat shrinkage rate was measured using two test pieces of the heat-shrinkable film, and the average value was used. Heat shrinkage rate (%) = {(100-LMD) / 100} × 100···(1) Heat shrinkage rate (%) = {(100-LTD) / 100} × 100···(2)

[0082] <Haze> The haze of the obtained heat-shrinkable film was measured using a haze meter (NDH5000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) according to the method of JIS Z7136. Furthermore, the haze was measured using four test pieces, and the average value was calculated.

[0083] <Glossiness> The gloss of the heat-shrinkable film was measured at an incident angle of 45° using a VG-2000 machine manufactured by Nippon Denshoku Kogyo Co., Ltd., in accordance with the method of JIS Z8741.

[0084] Impact Strength The obtained heat-shrinkable film was cut into samples of MD100 mm × TD100 mm to obtain test pieces. The test pieces were tested using a film impact testing machine manufactured by Toyo Seiki Co., Ltd., according to the method in JIS P8134. Specifically, the test piece was fixed on a table. Then, by removing the hooks securing the arm of the film impact testing machine, the fan-shaped arm rotated around its axis, and the impact head mounted at the front end of the arm pierced the test piece. The impact strength was calculated by quantifying the energy required for the impact head to pierce the test piece. The impact strength was determined by performing five measurements and calculating the average value.

[0085] <Compressive Strength> The compressive strength of the obtained heat-shrinkable film was determined according to JIS P8126. Specifically, the following method was used: The obtained heat-shrinkable film was cut into short strips with a length of 152.4 mm and a width of 12.7 mm. These strips were then placed in a cylindrical shape on a pre-fabricated support. The support was then placed on the stand of a ring crush tester (manufactured by Toyo Seiki Co., Ltd., model D) for testing. The test was performed only on the longitudinal (film travel direction) compressive strength, with n=8, and the average value was taken as the value.

[0086] Young's Modulus The obtained heat-shrinkable film was cut into samples of MD250 mm × TD5 mm to obtain test pieces. The test pieces were measured using a Strograph VE-1D manufactured by Toyo Seiki Co., Ltd., according to the method of ASTM D882. Furthermore, the Young's modulus was calculated by measuring four test pieces and obtaining their average value.

[0087] The results are shown below. [Table 6] project condition Original material membrane Recycled material membrane physical properties thermal shrinkage rate (10 s) MD / TD 70℃ % 0 / 6 0 / 7 80℃ % 4 / 37 5 / 37 90℃ % 8 / 54 9 / 55 100℃ % 11 / 63 10 / 64 Haze % 5.4 5.6 gloss % 134 138 Impact strength J 0.47 0.45 Compressive strength N 8.5 8.3 Young's Modulus MD / TD GPa 1.4 / 1.8 1.3 / 1.9

[0088] As shown in Table 6, there is no significant change in physical properties between the original material membrane and the recycled material membrane, and the recycled material membrane can be used in the same way as the original material membrane.

[0089] 11: Level 1 12: Level 2 13: The 3rd floor

Claims

1. A method for recovering a cyclic olefin resin, comprising: a first step of dissolving a composite material containing at least a cyclic olefin resin, a petroleum resin, and a different resin from the cyclic olefin resin and the petroleum resin in a solvent capable of dissolving the cyclic olefin resin and the petroleum resin to generate a solution, thereby precipitating the different resin component containing the different resin; a second step of obtaining a filtrate by filtering the solution and removing the different resin component; and a third step of obtaining a composition containing the cyclic olefin resin and the petroleum resin from the filtrate.

2. The method for recycling cyclic olefin resins as described in claim 1, wherein, In step 1 above, the composite material is cut into the specified size and then dissolved in the solvent.

3. The method for recycling cyclic olefin resins as claimed in claim 1 or 2, further comprising a fourth step of forming recycled material by melting and granulating the aforementioned components.

4. A method for recycling cyclic olefin resins as described in claim 1 or 2, wherein, The solvents mentioned above contain at least one of aromatic solvents, cyclic terpene solvents, cyclic ether solvents, and cyclic aliphatic solvents.

5. A method for recycling cyclic olefin resins as described in claim 1 or 2, wherein, The resin is at least one of the following: acrylic resin, ethylene resin, polyester resin, and polyamine resin.

6. A method for recycling cyclic olefin resins as described in claim 1 or 2, wherein, In step 1 above, the temperature of the solution is heated to above 25°C.

7. A method for recycling cyclic olefin resins as described in claim 1 or 2, wherein, In step 3 above, a composition comprising the cyclic olefin resin is obtained by any of the following methods: a first method, wherein the solvent is evaporated from the filtrate; a second method, wherein the composition comprising the cyclic olefin resin and the petroleum resin is precipitated by diluting the filtrate; or a third method, wherein the composition comprising the cyclic olefin resin and the petroleum resin is precipitated by cooling the filtrate.

8. A method for recycling cyclic olefin resins as described in claim 1 or 2, wherein, The composite material is formed from a membrane, which has at least a first layer containing the cyclic olefin resin and the petroleum resin, and a second layer containing the isomeric resin.

9. The method for recycling cyclic olefin resins as described in claim 8, wherein, At least one of the first layer and the second layer mentioned above contains additives.

10. A method for manufacturing a heat-shrinkable film, comprising: a step of recovering a composition comprising the cyclic olefin resin and the petroleum resin by means of the cyclic olefin resin recovery method of claim 1 or 2; and a step of using the recovered composition to replace a portion of the original material of the cyclic olefin resin to manufacture the heat-shrinkable film.

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