Composition for separating silicone-based polymer from polymer of mixed material containing silicone-based polymer and polymer having ester functional group, and separation method and separation process using same

Abstract

The present invention relates to a composition for separating a silicone-based polymer from a polymer of a mixed material containing a silicone-based polymer and a polymer having an ester functional group, and to a separation method and a separation process using same, and more specifically, to a composition for separating a silicone-based polymer, whereby the silicone-based polymer can be efficiently separated from a polymer of a mixed material containing a silicone-based polymer and a polymer having an ester functional group, and to a separation method and a separation process using same.

Description

Composition for separating a silicone polymer from a polymer of mixed material including a silicone polymer and a polymer having an ester functional group, a separation method and a separation process utilizing the same

[0001] The present invention relates to a composition for separating a silicone polymer from a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group, and a separation method and a separation process using the same. More specifically, the present invention relates to a composition for separating a silicone polymer capable of efficiently separating a silicone polymer from a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group, and a separation method and a separation process using the same.

[0002] Airbags for automobiles are components installed to protect passengers by absorbing the impact from a strong collision in the event of an accident. Initially, they were mostly installed only in the driver's seat for the driver's safety. However, with the improvement in automobile performance and function, awareness of safety has also changed significantly, and airbags are now installed in up to 12 locations, including the passenger seat, side curtains, and knees.

[0003] Recently, research on airbag reuse is actively being conducted due to the increasing demand for airbag materials and the increasing number of scrapped vehicles. Airbags work by instantly activating sodium azide when a strong impact is detected in an accident, inflating the airbag with a large amount of nitrogen gas to absorb the impact. To maintain the installation and operating environment of the vehicle, airbag materials can be made of high-strength yarn-based fibers, such as polyethylene terephthalate (PET), a polymer with an ester functional group that enables it to maintain its properties even under harsh conditions. To prevent gas leakage through gaps in the fabric during airbag inflation, cross-linked polydimethylsiloxane (PDMS) is used, which is coated on one side.

[0004] In addition to airbags, these materials are also used in various functional clothing and living materials, such as fabrics processed to be waterproof and heat-resistant, such as raincoats, swimsuits, waterproof mountaineering clothes, waterproof tents, and electrical insulating protective clothing.

[0005] The polymers containing ester functional groups used as fabrics in the above-mentioned mixed materials are recyclable into high-quality materials when collected or separated as single components. Therefore, there is an industrial need to selectively separate and recover only the polymers containing ester functional groups. To facilitate reuse or recycling, a technology is needed to selectively decompose or separate only the coated silicone polymers without causing significant loss or chemical transformation of the ester functional groups.

[0006] There have been several attempts to separate the fabric from the polymer mixture by removing the silicone-based polymer coated on the waste airbags instead of incinerating or disposing of the waste airbags in the environment after use, and then recycle the fabric from the polymer mixture. For example, Japanese Patent No. 7118485 proposes a technique for treating at least a portion of the airbag components using a surfactant including an alkali or alkaline earth metal hydroxide, sodium alkylsulfonate, and polyoxyethylene alkyl ether phosphate, thereby peeling at least a portion of the silicone material from the plastic fiber, and Japanese Patent Laid-Open No. 2009-299242 proposes a method for separating the silicone-based polymer from the coated fiber for an airbag coated with the silicone-based polymer using a composition for releasing a coated fiber for an airbag containing a surfactant, an alkali, and an aqueous carrier. In addition, Japanese Patent No. 7383093 proposes a method for recycling a silicone-coated resin substrate, which includes a process of immersing a resin substrate coated with a silicone resin in a silicone solution comprising 0.01 to 30 mass% of a tetraalkylammonium salt and 70 to 99.99 mass% of an organic solvent, as a method for recovering a depolymerized product of a coated silicone resin and a resin substrate.

[0007] However, these technologies can significantly reduce economic viability due to the use of expensive additives that are relatively difficult to recover. Furthermore, separation occurs under heated conditions, consuming significant energy. Furthermore, separation rates are limited, preventing the production of high-purity polymers. Furthermore, the solvent consumption used to separate silicon-based polymers leads to excessive process costs.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 0001) Japanese Patent No. 7118485 (Registration Date: August 5, 2022)

[0011] (Patent Document 0002) Japanese Patent Publication No. 2009-299242 (Published on December 24, 2009)

[0012] (Patent Document 0003) Japanese Patent No. 7383093 (Registration Date: 2023.11.09.)

[0013] The main purpose of the present invention is to solve the above-mentioned problem, and to provide a composition for separating a silicon-based polymer and a separation method using the same, which can recover a high-purity polymer material having an ester functional group by effectively and completely separating a silicon-based polymer from a polymer of a mixed material including a silicon-based polymer and a polymer having an ester functional group.

[0014] In addition, the present invention aims to provide a process for separating a silicon-based polymer from a polymer of a mixed material containing a silicon-based polymer, which effectively selectively separates only a silicon-based polymer from a polymer of a mixed material containing a silicon-based polymer, and at the same time, minimizes the amount of energy used for polymer separation as well as the loss of compounds forming a composition for separation and enables reuse thereof, thereby saving costs required for the process and greatly improving process efficiency.

[0015] In order to solve the above problem, the present invention provides a composition for separating a silicon-based polymer, characterized in that it comprises at least one alkali metal salt compound selected from the group consisting of alkali metal hydroxide salts, alkali metal alkoxide salts, alkali metal carbonates, and alkali metal bicarbonates; monohydric alcohols; and an organic solvent that causes swelling of the silicon-based polymer.

[0016] In one embodiment of the composition for separation of the present invention, the monohydric alcohol is a straight-chain alcohol or branched alcohol having 1 to 12 carbon atoms, and the organic solvent may be characterized by being at least one selected from an ether in which hydrocarbons are connected to each other by oxygen, a ketone in which alkyl groups are bonded to a carbonyl group (C=O), a monocyclic aromatic compound substituted or unsubstituted by an alkyl group, an organic solvent in which one or more halogen elements are directly bonded to carbon of a hydrocarbon, and an alkane compound having 5 to 30 carbon atoms.

[0017] In another embodiment of the separation composition of the present invention, the alkali metal salt compound may be at least one selected from the group consisting of KOH, K2CO3, NaOH, CH3OK, CH3ONa, C2H5OK, C2H5ONa, KHCO3, Na2CO3, and NaHCO3.

[0018] In another embodiment of the separation composition of the present invention, the alkali metal salt compound may be 0.01 wt% to 20 wt% based on the total weight of the composition, and the organic solvent may be at least one selected from the group consisting of methyl ethyl ether, diethyl ether, methyl phenyl ether, ethyl phenyl ether, furan, pyran, oxetane, tetrahydrofuran (THF), tetrahydropyran (THP), acetone, methyl ethyl ketone (MEK), diethyl ketone (DEK), methyl propyl ketone, methyl isobutyl ketone (MIBK), alkoxy benzene, chloromethane, dichloromethane, chloroform, tetrachloromethane, chlorobenzene, dichlorobenzene, benzene, toluene, xylene, ethylbenzene, styrene, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane.

[0019] In addition, the present invention provides a method for separating a silicon-based polymer from a polymer of a mixed material comprising a silicon-based polymer and a polymer having an ester functional group, characterized by comprising a step of contacting a composition for separating a silicon-based polymer, the composition comprising at least one alkali metal salt compound selected from the group consisting of alkali metal hydroxide salts, alkali metal alkoxide salts, alkali metal carbonates, and alkali metal bicarbonates; monohydric alcohols; and an organic solvent causing swelling of the silicon-based polymer, with the polymer of a mixed material comprising a silicon-based polymer and a polymer having an ester functional group, thereby selectively dissolving and separating the silicon-based polymer from the polymer of the mixed material.

[0020] In one embodiment of the separation method of the present invention, the polymer of the mixed material may further include one or more selected from natural or synthetic polymer materials with different characteristics, such as cotton, hemp, wool, silk, acrylic, polyethylene, polypropylene, polyurethane, and polyamide, in addition to the silicone-based polymer and the polymer having an ester functional group, and the contact may be performed at a temperature of 10°C to 100°C or without supplying heat energy from the outside.

[0021] In another embodiment of the separation method of the present invention, the alkali metal salt compound may be at least one selected from the group consisting of KOH, K2CO3, NaOH, CH3OK, CH3ONa, C2H5OK, C2H5ONa, KHCO3, Na2CO3, and NaHCO3, and after the contacting step, a step of purifying the separated polymer having an ester functional group and / or a silicone-based polymer by at least one method selected from the group consisting of filtration, washing, distillation, drying, and extraction may be further included.

[0022] In another embodiment of the separation method of the present invention, after the contacting step, a step of recovering the separated polymer having an ester functional group into a monomer through a depolymerization reaction may be further included.

[0023] In another embodiment of the separation method of the present invention, it may be characterized in that some or all of the alkali metal salt and organic solvent are recovered and reused.

[0024] In addition, the present invention provides a process for separating a silicone polymer from a polymer of a mixed material comprising a polymer having an ester functional group and a silicone polymer, characterized in that the process comprises the steps of: (a) adding a composition for separating a silicone polymer to a polymer of a mixed material comprising a polymer having an ester functional group and a silicone polymer, thereby selectively dissolving the silicone polymer from the polymer of the mixed material; (b) filtering the mixed solution in which the silicone polymer is dissolved in the step (a) to separate the polymer having an ester functional group; (c) removing at least a portion of the solvent from the filtrate filtered in the step (b) to precipitate the silicone polymer; (d) filtering the solution in which the silicone polymer is precipitated in the step (c) to separate the silicone polymer; and (e) recycling the solvent removed in the step (c) and the filtrate filtered in the step (d) as the composition for separating the silicone polymer of the step (a).

[0025] In addition, in another embodiment of the process for separating a silicon-based polymer from a polymer of the mixed material of the present invention, the composition for separating the silicon-based polymer may be characterized by including an alkali metal salt compound, monohydric alcohols, and an organic solvent that causes swelling of the silicon-based polymer.

[0026] In addition, in another embodiment of the process for separating a silicon-based polymer from a polymer of the mixed material of the present invention, the removal of the solvent in step (c) may be characterized in that it is carried out through evaporation.

[0027] In addition, in another embodiment of the process for separating a silicone-based polymer from a polymer of the mixed material of the present invention, the boiling point of the organic solvent may be characterized as being lower than the boiling point of a monohydric alcohol.

[0028] In addition, in another embodiment of the process for separating a silicon-based polymer from a polymer of the mixed material of the present invention, the step (e) may be characterized in that the solvent removed in the step (c) and the filtrate filtered in the step (d) are recycled as a composition for separating a silicon-based polymer of the step (a) by controlling the temperature to a predetermined temperature through a heat exchanger.

[0029] In addition, in another embodiment of the process for separating a silicone-based polymer from a polymer of a mixed material of the present invention, the polymer of the mixed material may be characterized in that, in addition to the silicone-based polymer and the polymer having an ester functional group, it further includes at least one selected from cotton, hemp, wool, silk, acrylic, polyethylene, polypropylene, and polyurethane.

[0030] In addition, in another embodiment of the process for separating a silicon-based polymer from a polymer of the mixed material of the present invention, step (a) may be characterized in that it is performed at 10°C to 100°C.

[0031] In addition, in another embodiment of the process for separating a silicone-based polymer from a polymer of the mixed material of the present invention, the process may further include a step of purifying the silicone-based polymer separated in step (d) by washing and drying the polymer having an ester functional group separated in step (b).

[0032] The composition for separating a silicone-based polymer according to the present invention can effectively and completely separate a silicone-based polymer from a polymer of a mixed material including a silicone-based polymer and a polymer having an ester functional group, thereby having the effect of recovering and recycling a polymer having an ester functional group at a level equivalent to that of a new material and a silicone-based polymer, respectively.

[0033] In addition, the present invention provides a simple process capable of effectively separating a silicone polymer without deterioration of physical properties or damage or deformation of the polymer forming the mixed material by adding a composition for separating a silicone polymer to a polymer of a mixed material including a polymer having an ester functional group and a silicone polymer, dissolving only the silicone polymer, and then separating the same.

[0034] In addition, the process according to the present invention minimizes the loss of the composition for separating silicone-based polymers and establishes an in-process recycling system that can reuse it, thereby separating recyclable single-material polymers and discharging them outside the process, and the compounds used for separation can be recovered and reintroduced into a new process for separating mixed-material polymers. Accordingly, waste generation is minimized and there is almost no waste of materials, so the cost required for the process can be reduced. In addition, since separation and recovery of materials can be performed simultaneously, efficiency can be greatly improved even with a simple process configuration.

[0035] Furthermore, in the process according to the present invention, selective dissolution or separation of silicone-based polymers can occur without the application of external heat energy during the process of separating polymers of mixed materials. In other words, highly effective separation can be induced even at room temperature or ambient temperature without heating or cooling. Furthermore, by modifying the process conditions for each flow, a thermodynamic phase change in the polymer is induced, which is then physically filtered. This method reduces energy consumption and allows for easy process implementation and operation. Furthermore, since the separation efficiency is not affected by external atmospheric pressure or humidity, successful process operation is possible regardless of the external environment or season.

[0036] Figure 1 is a schematic diagram explaining the principle and process by which alcohol penetrates into a silicone polymer matrix swollen by an organic solvent to form hydrogen bonds, thereby causing the adhesiveness of silicone polymers to stick to each other to be lost and the silicone polymers to be dissolved in a mixed solvent.

[0037] Figure 2 is a photograph of a pure PET fabric (b) recovered after the silicone polymer is dissolved and removed through contact with a polymer material (a) of a mixed material in which PET fabric is coated with a silicone polymer and a mixture according to one embodiment of the present invention (Example 1), observed under an enlarged microscope.

[0038] Figure 3 is an observation of the cross-section (lateral side) of the fibers shown in Figure 2.

[0039] Figure 4 shows the infrared spectra obtained by measuring the front side (silicon-based polymer coating layer) and back side (exposed side of PET fabric) of the mixed polymer material used as a raw material using FTIR-ATR.

[0040] FIG. 5 shows infrared spectra obtained by measuring the front and back surfaces of fibers recovered after removing a silicone polymer from a polymer material of a mixed material shown in FIG. 4 according to one embodiment of the present invention using FTIR-ATR.

[0041] FIG. 6 shows 1H-NMR spectra measured for a pure PET fabric (b) recovered after the silicone polymer is dissolved and removed through contact with a polymer material (a) of a mixed material in which PET fabric is coated with a silicone polymer and a mixture according to an embodiment of the present invention (Example 1).

[0042] FIG. 7 is a graph showing the results obtained by dissolving and removing a silicone-based polymer through contact with a mixture according to one embodiment of the present invention (Example 1) of a polymer material of a mixed material in which a PET fabric is coated with a silicone-based polymer, and then adding an excess amount of a hydrophobic solvent (a) or an excess amount of a hydrophilic solvent (b) to the obtained mixed solution, and then measuring the residual solids (including a silicone-based polymer) obtained according to the purification method of one embodiment (the purification method of i to iii of Example 1). 1 H-NMR spectra are shown.

[0043] Figure 8 is a photograph showing the shape (a) of a polymer material of a mixed material in which PET fabric is coated with a silicone-based polymer and the shape (b) of PET fiber recovered after the silicone-based polymer is dissolved and removed according to Example 27 of the present invention.

[0044] FIG. 9 is a schematic diagram illustrating a process for separating a silicone polymer from a polymer of a mixed material including a polymer having an ester functional group and a silicone polymer according to one embodiment of the present invention.

[0045] FIG. 10 is a flowchart illustrating a process for separating a silicone polymer from a polymer of a mixed material including a polymer having an ester functional group and a silicone polymer according to one embodiment of the present invention.

[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

[0047] The terms “comprising,” “including,” or “having” used in this specification indicate the presence of features, values, steps, operations, components, parts, or combinations thereof described in the specification, and do not exclude the possibility that other features, values, steps, operations, components, parts, or combinations thereof not mentioned may exist or be added.

[0048] The reactions and mixing described below can be carried out at room temperature and pressure unless otherwise specified, and can be carried out under typical reaction and mixing conditions without additional additions. However, this should not be interpreted in a way that deviates from matters clearly understood by those skilled in the art.

[0049] The present invention relates to a composition for separating a silicone polymer, which can effectively separate a silicone polymer from a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group, and a separation method using the same.

[0050] The composition for separating a silicon-based polymer according to the present invention comprises an alkali metal salt compound, a monohydric alcohol, and an organic solvent, thereby effectively separating a silicon-based polymer from a polymer of a mixed material including a silicon-based polymer and a polymer having an ester functional group without deterioration of the properties of the silicon-based polymer or damage or deformation thereof, thereby enabling recovery and recycling of a polymer having an ester functional group at a level equivalent to that of a new material and a silicon-based polymer, respectively.

[0051] To avoid duplication, the description of each component above is provided in the method for separating a silicone polymer from a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group, which is described later.

[0052] A method for separating a silicone-based polymer from a polymer of a mixed material including a silicone-based polymer and a polymer having an ester functional group according to one embodiment of the present invention may include a step of contacting the polymer mixture with a composition for separating a silicone-based polymer to separate the silicone-based polymer from the polymer of the mixed material.

[0053] The separation method according to the present invention is useful for selectively separating a silicone polymer from a polymer of a mixed material comprising a silicone polymer and a polymer having an ester functional group, and the polymer of the mixed material comprising the silicone polymer and the polymer having an ester functional group may be included in a form in which the silicone polymer is coated, attached, adhered, adhered, or mixed with the polymer having an ester functional group, and in particular, may be included in the form of a yarn, fiber, fabric product, molded article, extruded article, or membrane. More specific examples thereof may include materials used in airbags, conveyor belts, fire-resistant fabrics, insulation, compensating agents, such as flexible sealing sleeves for pipe work, tubes, membranes, clothing, or other flexible materials used in the construction of interior or exterior fabrics, such as tents, stands, awnings, tarpaulins, swimsuits, swimwear, functional outdoor clothing other than swimwear, and protective clothing for electrical insulation.

[0054] The polymer of the mixed material of the present invention may further include one or more selected from natural or synthetic polymer materials with different properties, such as cotton, hemp, wool, silk, acrylic, polyethylene, polypropylene, polyurethane, and polyamide, in addition to the silicone-based polymer and the polymer having an ester functional group.

[0055] In the present invention, the polymer having the ester functional group may be a polymer formed by polycondensation of a dicarboxylic acid and a dialcohol, wherein the dicarboxylic acid is selected from the group consisting of terephthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, and combinations thereof, and the dialcohol is selected from the group consisting of ethylene glycol, trimethylene glycol, 1,2-propanediol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, decanedicarboxylic acid, dodecamethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene. glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, di(tetramethylene) glycol, tri(tetramethylene) glycol, polytetramethylene glycol, pentaerythritol, 2,2-bis(4-β-hydroxyethoxyphenyl)propane and combinations thereof.

[0056] For example, the colored polymer containing the ester functional group may be selected from polyethylene terephthalate (PET), polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), Vectran, and combinations thereof.

[0057] In addition, the above silicon-based polymer has a silane bond (Si-Si), a silazane bond (Si-N), and a carbosilane bond (Si-C). x H y), a polymer having a siloxane bond (Si-O), and refers to a polymer having excellent heat resistance and chemical stability, etc. Examples of the silicone-based polymer include, but are not limited to, methyl polysiloxane, dimethyl polysiloxane, cyclic dimethyl polysiloxane, methyl phenyl polysiloxane, methylhydrogen polysiloxane, cyclic methylhydrogen polysiloxane, dimethyl siloxane methyl (polyoxyethylene) siloxane copolymer, dimethyl siloxane methyl (polyoxypropylene) siloxane copolymer, polyether-modified silicone, methyl steel-modified silicone, alkyl-modified silicone, fluorine-modified silicone, higher fatty acid ester-modified silicone, higher alkoxy-modified silicone, alcohol-modified silicone, amino-modified silicone, mercapto-modified silicone, epoxy-modified silicone, carboxyl-modified silicone, silicone-modified acrylic resin, polysilane, polysilazane, polycarbosilane, etc.

[0058] A separation method according to one embodiment of the present invention uses a separation composition for selectively dissolving and separating only a silicon-based polymer from a polymer of a mixed material including a silicon-based polymer and a polymer having an ester functional group, and the silicon-based polymer separation composition may be characterized in that it includes, as an activator, at least one alkali metal salt compound selected from the group consisting of an alkali metal hydroxide salt, an alkali metal alkoxide salt, an alkali metal carbonate, and an alkali metal bicarbonate; monohydric alcohols; and an organic solvent that causes swelling of the silicon-based polymer.

[0059] In the above composition, the alkali metal salt compound acts as an activator that induces separation of the silicone polymer from the polymer surface having an ester functional group, and the alkali metal cation and the anion paired therewith are those that can form a strong interaction through electron donation and acceptance to the functional group forming the polymer bond, and specifically, it may be at least one alkali metal salt compound selected from the group consisting of alkali metal hydroxide salt, alkali metal alkoxide salt, alkali metal carbonate, and alkali metal bicarbonate, and preferably, in terms of performance and economy, it may be at least one selected from the group consisting of KOH, NaOH, CH3OK, CH3ONa, C2H5OK, C2H5ONa, K2CO3, KHCO3, Na2CO3, NaHCO3, etc. having potassium and sodium cations.

[0060] At this time, the alkali metal salt compound may be included in an amount of 0.01 wt% to 20 wt%, preferably 0.1 wt% to 5 wt%, based on the total weight of the composition. If the alkali metal salt compound is less than 0.01 wt% based on the total weight of the composition, the initial activation step, which can weaken the bonding force between the polymer having an ester functional group and the silicone-based polymer, may not sufficiently progress, so that separation may occur at a very slow speed, and the amount separated may also be limited. If it exceeds 20 wt%, not only may unnecessary waste of materials occur, but also corrosion may occur during the separation process and post-processing of the product, and problems may occur in cleaning and maintenance of the equipment, and excessively high pH may cause deformation or damage to the polymer having an ester functional group.

[0061] In addition, the monohydric alcohol is a straight-chain alcohol or branched alcohol having 1 to 12 carbon atoms, and has a relatively higher solubility in silicone polymers than water, so that it penetrates into a swollen silicone matrix, and as described in FIG. 1, through a change in the properties of the polymer surface, increases the flexibility of the polymer chain, prevents adhesion between silicone polymer chains, and forms a mixed solvent with an organic solvent to enable dissolution of the silicone polymer. Preferably, the monohydric alcohol may be methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, etc., and has a carbon number of 10 or less or a particle diameter of less than 1.0 nm.

[0062] The above-mentioned monohydric alcohol can exhibit the effects of the present invention even with a very small amount added, depending on the weight of the composite material to be treated and the composition of the silicone material. For example, the alcohol can exhibit the mixed solvent effect of the present invention even with a small amount (e.g., 0.01 mol%) of the total moles of the mixed solvent (alcohol + organic solvent). However, from the perspective of process efficiency and economic feasibility, it may be preferable to include it in an amount of about 2 mol% to 98 mol%.

[0063] Meanwhile, the organic solvent causes swelling of the silicon-based polymer, and although it may have low solubility in alkali metal salt compounds or weak polarity, it has a certain degree of miscibility with the silicon-based polymer and is therefore not classified as a non-solvent. In addition, when forming a mixture for separating the silicon-based polymer according to the present invention, it is a non-reactive, inert solvent that does not cause a chemical reaction with the alkali metal salt, alcohol, applied composite material, or the organic solvent itself used together, and does not participate in any reaction during the separation and washing process.

[0064] The organic solvent may be at least one selected from among an ether in which hydrocarbons are linked to each other by oxygen, a ketone in which alkyl groups are bonded to a carbonyl group (C=O), a monocyclic aromatic compound substituted or not by an alkyl group, an organic solvent in which one or more halogen elements are directly bonded to carbon of a hydrocarbon, and an alkane compound having 5 to 30 carbon atoms. It is preferable that the organic solvent exist in a liquid state during the process of manufacturing a mixed solvent, but have appropriate fluidity. From this point of view, the number of carbon atoms in the alkyl group bonded to the hydrocarbon in the ether and the ketone and the alkyl group substituted in the monocyclic aromatic compound is preferably 1 to 20, more preferably 1 to 10, and most preferably 1 to 6.

[0065] More specifically, the ether organic solvent may be a type in which alkyl groups are bonded to each other, such as methyl ethyl ether, diethyl ether, methyl phenyl ether, and ethyl phenyl ether; a cyclic ether such as furan, pyran, oxetane, tetrahydrofuran (THF), and tetrahydropyran (THP); a ketone such as acetone, methyl ethyl ketone (MEK), diethyl ketone (DEK), methyl propyl ketone, and methyl isobutyl ketone (MIBK); or an alkoxy benzene; but in terms of the speed of promoting rapid swelling at an early stage, an ether having a simple structure, such as THF or methoxy benzene, may be more useful.

[0066] In addition, the organic solvent having the above halogen group may be chloromethane, dichloromethane, chloroform, tetrachloromethane, chlorobenzene, dichlorobenzene, etc., and the aromatic compound substituted or unsubstituted by an alkyl group may be benzene, toluene, xylene, ethylbenzene, styrene, etc.

[0067] Additionally, alkane hydrocarbon compounds with low polarity can also be used as organic solvents, and those that can exist in a condensed phase (liquid phase) at room temperature or heated temperature, such as pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane, may be preferable.

[0068] It may be more advantageous for the organic solvent to swell the silicone polymer and rapidly promote the penetration of alcohol and alkali metal salts into the polymer. For this purpose, compounds that are hydrophobic and have low polarity and do not significantly interfere with interactions (e.g., hydrogen bonding) that may occur between functional groups forming the silicone polymer chain (e.g., siloxane (-Si-O-)) and alcohol, such as dichloromethane, chlorobenzene, toluene, 1-hexane, and 1-heptane, may be more preferable.

[0069] In addition, the composition of the present invention may further include moisture and / or additives depending on the environment and needs of separation in addition to the aforementioned alkali metal salt compound, monohydric alcohol, and organic solvent, and the additives may be selected without limitation in an amount commonly used within a range that does not impair the physical properties of a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group for selectively dissolving and separating the silicone polymer.

[0070] The composition for separating a silicon-based polymer according to the present invention can selectively dissolve only the silicon-based polymer from the polymer of the mixed material by contacting the polymer of the mixed material including the silicon-based polymer and the polymer having an ester functional group.

[0071] Here, contact means contact between a polymer of a mixed material including a silicone-based polymer to be separated and a polymer having an ester functional group and a composition for separating a silicone-based polymer according to the present invention. The contact preferably occurs throughout the entire polymer of the mixed material to be processed, and may be in the form of immersion so that the polymer of the mixed material is sufficiently wetted in the composition for separating a silicone-based polymer according to the present invention.

[0072] The method for the above contact may include not only complete immersion, but also partial immersion and repeated immersion. The contact process may involve stirring of the composition. If necessary, the entire polymer of the mixed material may be divided into parts and sequentially contacted with the composition. The specific method for such contact may be selected within the scope of ordinary creative ability, taking into consideration time, cost, content, etc.

[0073] For example, the content of the composition for separating the silicone-based polymer can be appropriately selected depending on the weight of the silicone-based polymer to be separated, and preferably, 0.01 to 100 parts by weight can be brought into contact based on 1 part by weight of the polymer of the mixed material including the silicone-based polymer and the polymer having an ester functional group. When the composition for separating the silicone-based polymer of the above content range is used, the silicone-based polymer can be dissolved and separated from the polymer of the mixed material economically and effectively.

[0074] In addition, the contact between the silicone-based polymer separation composition and the polymer of the mixed material may be carried out while applying heat from the outside, or may be carried out without applying heat from the outside at all. The temperature at the time of the contact may be 10°C to 100°C, preferably 25°C to 60°C, for a predetermined period of time, and the contact time may vary depending on conditions such as the contact temperature, the concentration of the silicone-based polymer, and the amount of the polymer, but may be, for example, 1 hour to 24 hours.

[0075] If the above contact temperature is below 10℃, the effect on swelling and dissolution of the polymer may be limited, and if it exceeds 100℃, too much energy may be wasted unnecessarily, and operation at normal pressure may become difficult due to the vapor pressure of the low-boiling-point solvent. In addition, if the separation tank is made of glass or metal, heating it to a high temperature in the presence of an alkali metal salt and exposing it for a long time may cause corrosion or damage to the walls of the separation tank.

[0076] During the separation process of the silicone polymer according to the present invention, some of the polymers having ester functional groups may depolymerize, depending on the type of separation composition. In this case, to reduce the degree of depolymerization of the polymers having ester functional groups, the contact temperature can be lowered to prevent depolymerization of the polymers having ester functional groups.

[0077] In addition, a separation method for separating a silicone-based polymer from a polymer of a mixed material including a silicone-based polymer and a polymer having an ester functional group according to one embodiment of the present invention may further include a purification step for separating and recovering the polymer having an ester functional group and / or the silicone-based polymer separated after contact between the composition for separating the silicone-based polymer and the mixture.

[0078] After the above contact step, the silicone polymer dissolved into the separation composition may be partially attached again to the surface of the polymer having an ester functional group, and the residue of the decomposition product present in the composition may exist in the polymer having an ester functional group. Therefore, the polymer having an ester functional group separated from the polymer of the mixed material and the silicone polymer dissolved and separated may be separated by one or more purification methods among filtration, washing, distillation, evaporation, drying, extraction, etc., and it will be clearly understood that these purification methods can be carried out by conventional methods in the art.

[0079] Afterwards, the polymer having an ester functional group and the silicone polymer separated and recovered from the mixed material polymer including the silicone polymer and the polymer having an ester functional group can be pelletized through a melt extrusion process using an extruder or the like and then supplied as a direct raw material for physical reprocessing, and can also be used as a raw material for a depolymerization process to produce a recycled monomer that can be utilized in the resynthesis of polymer materials.

[0080] In addition, the composition remaining or recovered after separating the silicone-based polymer and the polymer having an ester functional group may be reintroduced as part of a composition for separating a new polymer of mixed material through the purification step described above.

[0081] Therefore, the method for separating a silicone-based polymer and a polymer having an ester functional group according to the present invention can effectively separate a silicone-based polymer from a polymer of a mixed material containing a silicone-based polymer and a polymer having an ester functional group without causing serious loss or chemical modification of the polymer having an ester functional group by a simple method at near ambient pressure and temperature.

[0082] In addition, the separation method according to the present invention can dissolve alkali metal salts that do not dissolve well when using only an organic solvent, by adding alcohol to the organic solvent to form a mixed solvent, thereby forming a uniform liquid phase, and can further improve the economic feasibility of the entire recycling process because some or all of the alkali metal salts and organic solvents used can be recovered and reused.

[0083] Hereinafter, with reference to the attached drawings, a process for separating a silicon-based polymer using the composition for separating a silicon-based polymer according to the present invention will be described in detail.

[0084] FIG. 9 is a schematic diagram illustrating a process for separating a silicone-based polymer from a polymer of a mixed material (a polymer having an ester functional group is used as an example in FIG. 9) according to one embodiment of the present invention, and FIG. 10 is a flowchart illustrating the same.

[0085] As illustrated in FIGS. 9 and 10, the process for separating a silicone-based polymer from a mixed-material polymer according to the present invention comprises: (a) adding a composition for separating a silicone-based polymer to a mixed-material polymer including a polymer having an ester functional group and a silicone-based polymer, thereby selectively dissolving the silicone-based polymer from the mixed-material polymer; (b) filtering the mixed solution in which the silicone-based polymer is dissolved in step (a), thereby separating the polymer having an ester functional group; (c) removing at least a portion of the solvent from the filtrate filtered in step (b), thereby precipitating the silicone-based polymer; (d) filtering the solution in which the silicone-based polymer is precipitated in step (c), thereby separating the silicone-based polymer; and (e) recycling the solvent removed in step (c) and the filtrate filtered in step (d) as the composition for separating the silicone-based polymer of step (a). At this time, the composition for separating the silicon-based polymer may include an alkali metal salt compound, monohydric alcohols, and an organic solvent that causes swelling of the silicon-based polymer.

[0086] As described above, the present invention can recover and recycle the silicone polymer and the polymer having an ester functional group by separating the silicone polymer and the polymer having an ester functional group by selectively dissolving only the silicone polymer from the polymer of the mixed material using a composition for separating the silicone polymer.

[0087] In addition, since the mixed solution of the solvent removed in step (c) and the filtrate filtered in step (d) is ultimately the composition for separating the silicon-based polymer, the present invention can minimize the generation of waste in the process and improve process efficiency through cost savings by recovering and reusing the composition for separating the silicon-based polymer through step (e).

[0088] Below, the above steps will be explained in more detail.

[0089] First, the step (a) is a step of selectively dissolving the silicon-based polymer from the polymer of the mixed material by contacting the polymer of the mixed material including the polymer having an ester functional group and the silicon-based polymer in a dissolution tank (100).

[0090] At this time, the contacting means contact between the polymer of the mixed material including the silicone-based polymer to be separated and the polymer having an ester functional group and the composition for separating the silicone-based polymer, and it is preferable that the contact occurs throughout the polymer of the mixed material including the silicone-based polymer to be processed and the polymer having an ester functional group, which means immersing the target material having a mixed form of the silicone-based polymer and the polymer having an ester functional group so as to be sufficiently wetted in the solvent.

[0091] The method for the above contact may include not only complete immersion, but also partial immersion and repeated immersion. The contact process may involve stirring of the composition. If necessary, portions of the entire polymer may be sequentially contacted with the composition. The specific method for such contact may be selected within the scope of ordinary creative ability, taking into consideration time, cost, content, etc.

[0092] For example, in the step (a), the content of the composition for separating a silicon-based polymer can be appropriately selected depending on the weight of the silicon-based polymer to be separated, and preferably, 0.01 to 100 parts by weight can be brought into contact based on 1 part by weight of a polymer of mixed material including a silicon-based polymer and a polymer having an ester functional group. The composition for separating a silicon-based polymer within the above content range can economically and effectively dissolve and separate a silicon-based polymer from a silicon-based polymer-containing polymer.

[0093] In addition, the step (a) may be performed by applying heat from the outside when the silicone-based polymer separation composition and the polymer of the mixed material come into contact, or may be performed without applying any heat from the outside at all. The temperature at the time of the contact may be 10°C to 100°C, preferably 25°C to 60°C, for a predetermined period of time, and the contact time may vary depending on conditions such as the contact temperature, the concentration of the silicone-based polymer, and the amount of the polymer, but may be, for example, 1 hour to 24 hours.

[0094] If the above contact temperature is less than 10°C, the effect on swelling and dissolution of the polymer may be limited, and if it exceeds 100°C, too much energy may be wasted unnecessarily, and operation at normal pressure may become difficult as the vapor pressure of the low-boiling-point solvent is generated. In addition, if the dissolution tank (100) is made of glass or metal, heating it to a high temperature in the presence of an alkali metal salt and exposing it for a long time may cause corrosion or damage to the wall of the dissolution tank (100).

[0095] In the above step (b), the mixed solution in which the silicon-based polymer is dissolved in the above step (a) is filtered (110) to separate the polymer having an ester functional group, and the separated filtrate is transferred to a concentrator (120).

[0096] In addition, the polymer separation in the step (b) may use a physical separation method such as filtration, membrane separation, centrifugation, etc., and in the filtration method, in addition to the method of filtering solids or solids through the flow of fluid, such as atmospheric filtration, reduced pressure filtration, and pressurized filtration using filter paper, filter cloth, strainer, and microfilter, although the filtration medium is fixed, dynamic filtration methods in which centrifugal force or reciprocating motion is also used may be utilized. In addition to filtration, various methods for separating solids and liquids or high molecular weight substances and low molecular weight substances, such as membrane separation, dialysis, centrifugation, and separation methods based on density differences between substances, may be used, but in terms of separation efficiency and speed, a separation method by filtration may be most preferably utilized.

[0097] In addition, the present invention may further include a step of purifying a polymer having a polymer functional group having an ester functional group separated in step (b) by washing and drying the polymer.

[0098] The above step (c) is a step of removing at least a portion of the solvent from the filtrate filtered in step (b) using a concentrator (120) to precipitate a silicone-based polymer. The concentrator is not limited as long as it has a means for removing a portion of the solvent, but it may be preferable from the standpoint of operation and convenience to use a method of removing the solvent by changing it into a gaseous phase through evaporation. When at least a portion of the solvent is removed from the filtered filtrate, the saturated solubility of the silicone-based polymer in the solution decreases, so the silicone-based polymer is precipitated from the solution.

[0099] At this time, it is preferable that the solvent removed from the filtrate is an organic solvent rather than a monohydric alcohol. This is because the silicone polymer has a higher affinity for the organic solvent than for the monohydric alcohol, so first removing the organic solvent from the mixed solution induces the precipitation of the silicone polymer, making it easier to separate it from the solution. Therefore, when removing some of the solvent through evaporation, it is preferable that the organic solvent in the aforementioned composition for separating the silicone polymer has a lower boiling point than the monohydric alcohol. On the other hand, the alkali metal salt compound, which is an activator used to induce the separation of the silicone polymer from the polymer having an ester functional group, exists in a homogeneous or highly dispersed state in a solution in which the concentration of the monohydric alcohol increases after the organic solvent has evaporated, and this is clearly distinguished from the solid phase consisting of the silicone polymer. Therefore, the separation of the silicone polymer and the recovery of the monohydric alcohol mixture containing the activator can be carried out by a simple method such as filtration.

[0100] The solvent removed from the concentrator (120) in the above step (c) is transferred to the first solvent storage tank (140), and the solution in which the silicon-based polymer is precipitated is transferred to the filter (130).

[0101] In one embodiment of the present invention, when the solvent is removed through evaporation in step (c), the evaporation is performed at a temperature of 30°C to 100°C, preferably 50°C to 70°C. If the temperature is lower than 30°C, separation may not occur or the separation speed may be slow, and if it exceeds 100°C, excessive energy may be consumed and the separation efficiency may be reduced. The pressure at this time may be reduced or pressurized depending on the situation.

[0102] The above step (d) filters the solution in which the silicon-based polymer precipitated in the above step (c) is transferred to the filter (130), thereby separating the silicon-based polymer, and the filtered filtrate is transferred to the second solvent storage tank (150).

[0103] In addition, the separation method in step (d) may be a physical separation method such as filtration, membrane separation, centrifugation, etc. similar to the separation method in step (b). Preferably, a separation method by filtration may be used.

[0104] In addition, the present invention may further include a step of purifying the silicon-based polymer separated in step (d) by washing and drying it.

[0105] The above step (e) is a step of recycling the solvent removed in the above step (c) and the filtrate filtered in the above step (d) as a composition for separating a silicone-based polymer in the above step (a), and the condensed solvent obtained with a higher composition of the first solvent (organic solvent) through the above step (c) and the filtrate obtained with a higher composition of the second solvent (monohydric alcohol) through the above step (d) can be stored in each of the storage tanks (140 and 150), and can be resupplied to the dissolution tank (100) to be reused as a composition for separating a silicone-based polymer in the above step (a).

[0106] For reference, the above description and drawings show a storage tank (140) for storing the organic solvent mainly recovered through step (c) and a storage tank (150) for storing the filtrate from which silicon has been removed through step (d) as separate configurations, but this is merely exemplary, and in reality, after recovery to one solvent storage tank, it may be re-supplied to the dissolution tank (100) used in step (a).

[0107] In addition, in the step (e), the organic solvent evaporated in the step (c) and the filtrate filtered in the step (d) can be mixed and recycled as the silicone-based polymer separation composition of the step (a) and then adjusted to a predetermined temperature through a heat exchanger (160).

[0108] Through this, by controlling the temperature of the composition for separating a silicon-based polymer to the temperature conditions required for dissolving the silicon-based polymer in step (a), it is not necessary to supply separate heat from the outside of the dissolution tank (100) into the dissolution tank (100) in step (a).

[0109] Hereinafter, the present invention will be described in more detail by way of preferred embodiments thereof to aid understanding; however, the following embodiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0110]

[0111] <Activator for Separating Silicone Polymers from Mixed Polymers>

[0112] The following are examples and comparative examples to determine the type and performance of an activator that can induce direct separation between materials when it penetrates into the polymer interface among the compositions of a mixture that can be applied to separate a silicone-based polymer from a waste polymer material of a mixed material in which a silicone-based polymer is coated on a polyethylene terephthalate (PET) fiber.

[0113]

[0114] [Example 1]

[0115] (a) Separation of silicone polymer from mixed polymer

[0116] Polydimethylsiloxane (PDMS), a mixed polymer with a silicone polymer, was prepared by cutting waste airbag fibers (PDMS content 23.9% by weight) onto PET fibers and cutting them into 2 cm × 2 cm pieces. The composition was prepared by mixing 7.18 g (156 mmol) of anhydrous ethanol (Alfa Aesar, anhydrous), 13.25 g (156 mmol) of dichloromethane (DCM; Sigma-Aldrich, purity 99.8% or higher), and 0.034 g (0.6 mmol) of KOH. The above-mentioned prepared composition was placed in a round-bottom flask and heated, and when the temperature of the liquid mixture was maintained at a constant 40°C, 0.2 g of the waste airbag fiber was brought into contact with it and completely immersed, and then stirred at 500 rpm for 2 hours at 40°C to perform an experiment to separate a silicone-based polymer from a waste airbag sample of a polymer material of a mixed material.

[0117] Separation was carried out through continuous contact with the polymer material and the liquid mixture, and when the target time was reached, the fiber polymer (main component: PET) with the silicone-based polymer partially or completely removed was taken out from the mixed solution, washed twice with an excess of distilled water maintained at 20°C or lower, and then washed 3 to 5 more times with ethanol, and then placed in a vacuum dryer maintained at 60°C under vacuum (≤ 2 mmHg) and dried for more than 12 hours to finally obtain a fiber with the silicone-based polymer removed. The polymer fiber finally obtained was subjected to the following characteristic analysis together with the polymer of the mixed material before the silicone-based polymer was removed.

[0118] (b) Comparative analysis of the properties of polymer fibers before and after separation of silicone polymers.

[0119] The surface and cross-sectional shapes and structures of the fabrics were observed using a stereoscopic microscope (model name: Olympus SZ61). Each polymer sample attached vertically and horizontally to a carbon sticker was coated with platinum (Pt sputtering), and then magnified to compare the shape changes before and after the separation of the silicone-based polymer. Figures 2 and 3 show photographs taken with a stereoscopic microscope of each fabric before and after the silicone-based polymer was removed. A silicone-coated layer was observed on one side (front side) of the raw material, but no coated layer was observed on the fabric from which the silicone-based polymer was removed (b in Figures 2 and 3).

[0120] Meanwhile, to determine the morphology and chemical structure of the constituent materials, infrared spectra were obtained for both surfaces (front and back) of the polymer fibers using an atomic force transducer-four-wave infrared spectroscopy (ATR-FTIR; Bruker ALPHA II). The front and back surfaces of the fabrics were measured before and after the removal of the silicone polymer, and the results are shown in Figs. 4 and 5. Before the silicone polymer was removed, bonding groups for the silicone polymer were observed on the front surface (Fig. 4), but after the removal, only characteristic peaks for PET were observed on the front surface (Fig. 5), just like on the back surface.

[0121] To measure the content of silicon in polymer fibers, pre-calibrated polymer fibers with known composition ratios are used. 1 H-NMR spectra were used. The calibration curve for quantification was prepared by mixing pure PET and pure silicone, but with the weight ratio of each sample known in advance (samples mixed so that the mass ratio of silicone is 0%, 5%, 10%, 15%, 20%, 25%, and 30%), and for each 1After measuring the H-NMR spectra, the relative area ratios of the characteristic peaks of PET and silicone were correlated as a function of the weight ratio of the constituent polymers. 20 mg of each polymer fiber sample was uniformly dissolved in 0.6 ml of a solvent composed of trifluoroacetic acid-d (TFA-d; Sigma-Aldrich) and dichloromethane-d2 (CD2Cl2; Sigma-Aldrich) in a volume ratio of 1:2, and then nuclear magnetic resonance (NMR) spectroscopy was performed (Model: Bruker AVANCE ∥). + 500MHz) 1 H-NMR spectra were obtained. Figure 6 shows the results measured for fabrics before and after removal of the silicone polymer. 1 It is shown by comparing H-NMR spectra.

[0122] The above calibration curve and 1 Based on the content of silicon-based polymer in the mixed polymer sample measured through H-NMR spectrum, the separation rate of silicon-based polymer from the mixed polymer sample was calculated using the following equation.

[0123]

[0124] Here, m0 is the weight of silicon in the polymer fiber sample of the initial mixed material, and m0 represents the weight of the silicon-based polymer remaining in the polymer fiber finally obtained after the silicon-based polymer separation process.

[0125]

[0126] (c) Recovery and qualitative analysis of separated and dissolved silicon polymers

[0127] In the process of separating the above material, the polymer fibers were separated to the outside, and the obtained liquid mixture (liquid in which the silicone polymer was uniformly dissolved) was used to recover the silicone polymer in a solid state using the following methods.

[0128] ⅰ) After removing all solvents in the liquid mixture using a rotary evaporator, the obtained solid was washed by adding an excessive amount of distilled water. The water-soaked solid was evaporated, dried, and washed again three or more times, and then placed in a vacuum dryer maintained at 60°C under vacuum (≤ 2 mmHg) and dried for more than 12 hours to completely remove the solvent, obtaining approximately 0.04 g of a solid mainly composed of a silicone polymer.

[0129] ⅱ) When 200 g of 1-hexane (Sigma, purity 99.0% or higher), an organic solvent, was further added to the above liquid mixture and diluted so that the ethanol composition became less than 3% by weight, precipitation of a silicone-based polymer occurred. The solution was allowed to stand for 3 hours or more to stabilize, and then the precipitated solid phase was separated using a filter. After washing with distilled water 3 to 5 times, the solvent was completely removed through the vacuum drying process described above, and approximately 0.05 g of a solid mainly composed of a silicone-based polymer was obtained.

[0130] ⅲ) A repetitive extraction process was used to induce phase separation by adding about 50 g of distilled water to the above liquid mixture, and to separate the aqueous phase from this. When the pH of the separated aqueous phase became 7 or lower, the extraction process was stopped, and the organic phase containing the silicone polymer and the organic solvent was taken, and the organic solvent was removed using a rotary evaporator to obtain a polymer sample. After completely removing the solvent through the vacuum drying process described above, about 0.05 g of a solid mainly composed of the silicone polymer was obtained.

[0131] Each solid obtained according to the above methods for recovering the silicon-based polymer was subjected to an infrared spectrum using ATR-FTIR, and compared with the ATR-FTIR measurement of the silicon-based polymer coated on the initial raw material described as an analysis example in process (b) above, to determine whether there was a change in the material constituting the surface. Figure 7 shows the infrared spectra of the solids finally obtained according to the purification methods i to iii in the process (c) of recovering the silicon-based polymer after separating the silicon-based polymer from the polymer of the mixed material.

[0132]

[0133] [Comparative Example 1]

[0134] Separation of polymer material was performed in the same manner as in Example 1, except that KOH was not used.

[0135]

[0136] [Example 2]

[0137] Separation of polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.024 g) of NaOH was used instead of KOH.

[0138]

[0139] [Comparative Example 2]

[0140] Separation of polymer material was performed in the same manner as in Example 1, except that 20.6 mmol (0.044 g) of Ca(OH) was used instead of KOH.

[0141]

[0142] [Example 3]

[0143] Separation of the polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.042 g) of CH3OK was used instead of KOH.

[0144]

[0145] [Example 4]

[0146] Separation of the polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.032 g) of CH3ONa was used instead of KOH.

[0147]

[0148] [Example 5]

[0149] Separation of the polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.041 g) of C2H5ONa was used instead of KOH.

[0150]

[0151] [Example 6]

[0152] Polymer material separation was performed in the same manner as in Example 1, except that 0.6 mmol (0.083 g) of K2CO3 was used instead of KOH, and 5.00 g (156 mmol) of anhydrous methanol (Sigma-Aldrich, purity 99.8% or higher) was used instead of anhydrous ethanol.

[0153]

[0154] [Example 7]

[0155] Separation of the polymer material was performed in the same manner as in Example 1, except that 30.6 mmol (0.067 g) of KHCO was used instead of KOH.

[0156]

[0157] [Comparative Example 3]

[0158] Separation of polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.060 g) of potassium acetate (CH3COOK) was used instead of KOH.

[0159]

[0160] [Comparative Example 4]

[0161] Separation of polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.050 g) of sodium acetate (CH3COONa) was used instead of KOH.

[0162]

[0163] [Comparative Example 5]

[0164] Separation of polymer material was performed in the same manner as in Example 1, except that 0.6 mmol (0.054 g) of oxalic acid (COOH)2) was used instead of KOH.

[0165]

[0166] [Comparative Example 6]

[0167] Polymer material separation was performed in the same manner as in Example 1, except that 0.6 mmol (0.072 g) of dimethoxy dimethyl silane (DMDMOS) was used instead of KOH.

[0168]

[0169] In the present invention, a liquid mixed solvent for separating a silicone polymer from a waste polymer material of a mixed material in which a silicone polymer is coated on a PET fiber is used, and an organic solvent that causes swelling of a monohydric alcohol and a silicone polymer is used. An activator that can induce separation of a material through strong interaction with a binding functional group of the polymer when it penetrates into a polymer substrate or interface can be used.

[0170] Table 1 shows compounds that are effective as activators for the separation of silicone polymers, compared to those that are not, using methanol or ethanol as a monohydric alcohol solvent and dichloromethane as an organic solvent that causes swelling of silicone polymers.

[0171] In Comparative Example 1, which used only a mixed solvent without an activator, the separation rate of the silicone-based polymer from the polymer material of the mixed material was observed to be low at 13.3%. On the other hand, when an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide was added to a mixed solvent composed of an organic compound that causes swelling of the silicone-based polymer and a monohydric alcohol, the separation of the silicone-based polymer from the polymer material of the mixed material proceeded very quickly and effectively even at a low temperature of 40℃ or less, as can be seen in the results of Examples 1 and 2. In such metal hydroxide-based base activators, an effective effect was observed when the cation was an alkali metal. When the same molar number of alkaline earth metal hydroxides was applied under the same conditions as in Comparative Example 2, the separation of the silicone-based polymer material or its dissolution into the mixed solvent hardly occurred even though the number of equivalents of hydroxide ions increased by two times.

[0172] The activator comprising one of the compositions for separating a polymer material of a mixed material according to the present invention may be an alkali metal alkoxide compound in addition to the alkali metal hydroxide. Examples 3 to 5 show the results of applying various alkali metal alkoxide compounds such as potassium methoxide, sodium methoxide, and sodium ethoxide as activators instead of alkali metal hydroxide. It can be seen that the separation of a silicon-based polymer from a polymer material of a mixed material proceeds very quickly and rapidly even at low temperatures below 40°C.

[0173] Alkali metal carbonate or alkali metal bicarbonate can also be effectively used as an activator for separating the polymer material of the mixed material according to the present invention. An anion paired with an alkali metal cation is carbonate (CO3 2- ) or bicarbonate (HCO3 - ) It can be confirmed that high activity is also observed in the case of Example 6 or Example 7 in which the activator is applied.

[0174] All of the examples above have demonstrated that salts composed of alkali metal cations are effective as activators. However, some compounds containing all alkali metal cations may be exceptionally ineffective as activators. Alkali metal acetate salts are representative examples. Comparative Examples 3 and 4 show examples in which potassium acetate and sodium acetate were added instead of the previously effective alkali metal salts as activators. Even though the same conditions as in the previous examples were applied, the separation rates were very poor, at 3.4% and 4.2%, respectively.

[0175] Among other organic compounds, the potential of oxalic acid (Comparative Example 5), a strong acid, as an activator was evaluated by adding it instead of the previously described alkali metal salt. However, no significant performance or effect on the separation of silicon-based polymers was observed. These results indicate that the function of the activator is not simply determined by the strength or degree of ionization of the acid.

[0176] Comparative Example 6 was performed to experimentally verify the hypothesis that silicone is decomposed by alcoholysis when alcohol is added as a solvent and that the resulting reaction intermediate is effective in separating silicone. The alcohol-added intermediate that can be generated according to the hypothesis can have high miscibility with the un-decomposed silicone polymer and can also have the effect of promoting the separation and dissolution of the silicone polymer from the composite material, and thus can be expected to function as an activator. However, as in the results of Comparative Example 6, a dramatic improvement in the separation rate of the silicone polymer was not observed, which means that no chemical transformation of the silicone occurred due to the addition of alcohol.

[0177]

[0178] <Effect of silicone polymer separation performance according to changes in mixed solvent composition>

[0179] The following are the results of a study conducted to determine the influence of the composition ratio of organic solvent and alcohol on the separation performance in forming a mixed solvent according to the present invention to separate a silicone-based polymer from a waste polymer material of a mixed material in which a silicone-based polymer is coated on PET fiber.

[0180]

[0181] [Comparative Example 7]

[0182] Polymer material separation was performed in the same manner as in Example 1, except that 312 mmol (14.35 g) of ethanol was used as a solvent and the organic solvent DCM was not added.

[0183]

[0184] [Comparative Example 8]

[0185] The polymer material separation was performed in the same manner as in Example 1, except that 312 mmol (26.50 g) of DCM was used as a solvent and no alcohol was added.

[0186]

[0187] [Example 8]

[0188] Separation of the polymer material was performed in the same manner as in Example 1, except that 18.7 mmol (0.86 g) of ethanol was used as the alcohol solvent and 605.3 mmol (51.41 g) of DCM was used.

[0189]

[0190] [Example 9]

[0191] Separation of the polymer material was performed in the same manner as in Example 1, except that 78 mmol (3.59 g) of ethanol was used as the alcohol solvent and 234 mmol (19.87 g) of DCM was used.

[0192]

[0193] [Example 10]

[0194] Polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (7.19 g) of ethanol was used as the alcohol solvent and 156 mmol (13.25 g) of DCM was used.

[0195]

[0196] [Example 11]

[0197] Polymer material separation was performed in the same manner as in Example 1, except that 234 mmol (10.78 g) of ethanol was used as the alcohol solvent and 78 mmol (6.62 g) of DCM was used.

[0198]

[0199] [Example 12]

[0200] Separation of the polymer material was performed in the same manner as in Example 1, except that 605.3 mmol (27.88 g) of ethanol was used as the alcohol solvent and 18.7 mmol (1.59 g) of DCM was used.

[0201]

[0202] In the present invention, a method can be used in which an organic solvent causing swelling of the silicone polymer and a monohydric alcohol for changing the surface properties of the silicone polymer are simultaneously applied as a liquid mixed solvent to separate the silicone polymer from a waste polymer material of a mixed material in which the silicone polymer is coated on PET fiber.

[0203] Table 2 shows that a small amount of potassium hydroxide (3.0 mmol per 1 g of mixed polymer) was added as an activator for the separation of silicon-based polymers, ethanol was used as a monohydric alcohol solvent, and dichloromethane was used as an organic solvent that causes swelling of silicon-based polymers, and the ratios were adjusted to observe the separation performance of silicon-based polymers from the mixed polymer materials.

[0204] In Comparative Example 7 (no organic solvent added), which did not add any of the components of the mixed solvent, the separation rate was approximately 20.6%, and in Comparative Example 8 (no alcohol added), the separation rate was very low at approximately 2.2%. On the other hand, when both the organic solvent and alcohol were added as part of the composition, the separation performance of the silicone-based polymer from the polymer of the mixed material was greatly improved.

[0205]

[0206] <Composition of mixed solvents effective for separation of silicone polymers - Types and range of alcohols>

[0207] The following examples and comparative examples are intended to define the types and ranges of alcohols that can be used to form a mixed solvent according to the present invention in separating a silicone polymer from a waste polymer material of a mixed material in which a silicone polymer is coated on PET fiber.

[0208]

[0209] [Example 13]

[0210] Polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (9.38 g) of isopropanol (Sigma-Aldrich, purity 98% or higher) was used instead of ethanol and the reaction temperature was changed to 60°C.

[0211]

[0212] [Example 14]

[0213] Polymer material separation was performed in the same manner as in Example 13, except that 1-propanol (Sigma-Aldrich, purity 98% or higher) was used instead of isopropanol.

[0214]

[0215] [Example 15]

[0216] The polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (11.56 g) of 1-butanol (Alfa Aesar, purity 99% or higher) was used instead of isopropanol.

[0217]

[0218] [Example 16]

[0219] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (13.75 g) of 1-pentanol (Sigma-Aldrich, purity 99% or higher) was used instead of isopropanol.

[0220]

[0221] [Example 17]

[0222] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (15.94 g) of 1-hexanol (Sigma-Aldrich, purity 99% or higher) was used instead of isopropanol.

[0223]

[0224] [Example 18]

[0225] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (20.32 g) of 1-octanol (Sigma-Aldrich, purity 99% or higher) was used instead of isopropanol.

[0226]

[0227] [Example 19]

[0228] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (24.69 g) of 1-decanol (Sigma-Aldrich, purity 98% or higher) was used instead of isopropanol.

[0229]

[0230] [Comparative Example 9]

[0231] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (42.20 g) of 1-octadecanol (Stearyl Alcohol; Sigma-Aldrich, purity 99% or higher) was used instead of isopropanol.

[0232]

[0233] [Comparative Example 10]

[0234] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (9.68 g) of ethylene glycol (Sigma-Aldrich, purity 99.8% or higher) was used instead of isopropanol.

[0235]

[0236] [Comparative Example 11]

[0237] Polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (14.37 g) of glycerol (Sigma-Aldrich, purity 99.5% or higher) was used instead of isopropanol.

[0238]

[0239] [Comparative Example 12]

[0240] The polymer material separation was performed in the same manner as in Example 13, except that 156 mmol (13.44 g) of hexane was used instead of isopropanol.

[0241]

[0242] In the present invention, a solvent mixed with an organic solvent and alcohol is used together with an activator to separate a silicone polymer from a waste polymer material of a mixed material in which a silicone polymer is coated on PET fiber, and to induce swelling and change in surface properties of the silicone polymer.

[0243] As shown in the diagram of the function of alcohol in Figure 1, when the applied alcohol comes into contact with the surface of a silicone polymer, the alcohol functional group portion (alcohol moiety) faces inward toward the inside of the polymer due to mutual attraction (hydrogen bonding) with the silicone polymer, and the alkyl moiety of the alcohol faces outward and can exhibit hydrophobicity, so that the silicone polymer's ability to adhere to each other or to other materials can be weakened.

[0244] Table 3 shows the types of alcohols effective for dissolving and separating silicone-based polymers from the polymer material of the mixed material, and their effects, of organic compounds having alcohol functional groups that can be introduced together with the organic solvent (dichloromethane) in the method of forming a mixed solvent according to the present invention. A small amount (3.0 mmol per 1 g of the polymer of the mixed material) of potassium hydroxide was applied as an activator, and dichloromethane having the same molar number as the alcohol was used as the organic solvent.

[0245] Example 13 is a mixed solvent composition using isopropanol, which is a branched alcohol, instead of ethanol. From the results of Example 13, it can be confirmed that when a branched alcohol is used as an alcohol for forming a mixed solvent, the separation rate is lower than when a linear alcohol having a short-chain alkyl group is used, but the decomposition rate of PET is rather very low. Since the separation rate increases when the contact time is increased, it can be seen that using a branched monohydric alcohol is another method for separating a silicone polymer while lowering the decomposition rate of PET, in addition to the method of lowering the temperature.

[0246] Examples 14 to 19 are experiments on the separation rate of silicone-based polymers according to the carbon number of the alcohol solvent when forming a mixed solvent for separating silicone-based polymers from a polymer material of a mixed material. When a linear monohydric alcohol having a straight-chain alkyl group with 8 or fewer carbon atoms was used as the alcohol solvent, the dissolution and separation of the silicone-based polymer from the polymer material of the mixed material proceeded very quickly, and the separation rate of the silicone-based polymer was 100% after 2 hours, and when the carbon number was 10, the separation rate slightly decreased to 91.1%. On the other hand, the decomposition rate of PET tended to decrease as the carbon number of the linear monohydric alcohol having a straight-chain alkyl group increased. It was confirmed that increasing the carbon number of the monohydric alcohol may be another method for increasing the separation rate of the silicone-based polymer while lowering the decomposition rate of PET.

[0247] The monohydric alcohol used in the previous examples corresponds to a substance having an amphiphilic molecule structure in which a hydrophilic alcohol functional group and a hydrophobic alkyl functional group are located at both ends. Dihydric or polyhydric alcohols may have hydrophobic terminals, and the hydrogen bonds that may be formed between them when in contact with a silicone-based polymer may be much more complex, and the form of the intramolecular interaction may be different from that shown in Figure 1. Comparative Examples 10 and 11 used ethylene glycol, which corresponds to a dihydric alcohol, and glycerol, which corresponds to a polyhydric alcohol, as alcohol solvents for the composition of the mixed solvent. In both cases, the performance for separating the silicone-based polymer from the polymer of the mixed material was observed to be very poor, at less than 13%.

[0248] Comparative Example 12 observed the separation performance by adding an alkane whose molecular terminals are all hydrophobic instead of an amphiphilic alcohol. This case was simply a mixture of two different organic solvents, and did not satisfy the conditions for exhibiting the function of the mixed solvent according to the present invention. As expected, the separation rate of the silicone-based polymer from the polymer of the mixed material was approximately 11.7%, indicating that the separation performance was relatively poor.

[0249]

[0250] <Composition of mixed solvents effective for separation of silicone polymers - Types and range of organic solvents>

[0251] The following examples and comparative examples are intended to define the types and ranges of organic solvents that can be used to form a mixed solvent according to the present invention in separating a silicone polymer from a waste polymer material of a mixed material in which a silicone polymer is coated on PET fiber.

[0252]

[0253] [Example 20]

[0254] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (11.25 g) of tetrahydrofuran (THF; Sigma-Aldrich, purity 99.0% or higher) was used instead of DCM.

[0255]

[0256] [Comparative Example 13]

[0257] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (2.81 g) of water was used instead of ethanol and 156 mmol (11.25 g) of THF was used instead of DCM as the organic solvent.

[0258]

[0259] [Example 21]

[0260] The separation of polymer materials was performed in the same manner as in Example 1, except that 156 mmol (13.75 g) of 1-pentanol was used as the alcohol instead of ethanol and 156 mmol (11.25 g) of THF was used as the organic solvent instead of DCM.

[0261]

[0262] [Comparative Example 14]

[0263] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (13.75 g) of ethyl acetate (Sigma-Aldrich, anhydrous, purity 99.8% or higher) was used instead of DCM.

[0264]

[0265] [Example 22]

[0266] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (9.06 g) of acetone (Sigma-Aldrich, purity 99.9% or higher) was used instead of DCM.

[0267]

[0268] [Example 23]

[0269] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (22.93 g) of dichlorobenzene (Sigma-Aldrich, anhydrous, purity 99% or higher) was used instead of DCM.

[0270]

[0271] [Example 24]

[0272] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (14.37 g) of toluene was used instead of DCM.

[0273]

[0274] [Comparative Example 15]

[0275] Separation of polymer material was performed in the same manner as in Example 24, except that KOH was not used.

[0276]

[0277] [Comparative Example 16]

[0278] Separation of the polymer material was performed in the same manner as in Example 24, except that no alcohol was added.

[0279]

[0280] [Example 25]

[0281] The polymer material separation was performed in the same manner as in Example 1, except that 156 mmol (16.56 g) of ethylbenzene (Sigma-Aldrich, anhydrous, purity 99.8% or higher) was used instead of DCM.

[0282]

[0283] [Example 26]

[0284] Separation of the polymer material was performed in the same manner as in Example 1, except that 156 mmol (16.87 g) of methoxybenzene (anisole) was used as the organic solvent instead of DCM.

[0285]

[0286] Table 4 shows the types of organic solvents effective for dissolving and separating silicone polymers from the polymer material of the mixed material, i.e., solvents for causing swelling of silicone polymers and forming an effective mixed solvent together with alcohol functional groups in forming a mixed solvent according to the present invention, and their effects. A small amount (3.0 mmol per 1 g of the polymer of the mixed material) of potassium hydroxide was used as an activator.

[0287] Example 20 shows the results of using the same molar number of tetrahydrofuran (THF) as the organic solvent in place of dichloromethane (DCM) in Example 1. Tetrahydrofuran is known to be a type of good solvent that exhibits a high degree of swelling when in contact with silicone-based polymers. Referring to the results of Example 20 in which THF was used as the organic solvent, as in Example 1, very rapid and effective separation and dissolution of the silicone-based polymer occurred.

[0288] Meanwhile, THF is a hydrophilic organic solvent that is highly miscible with water. When hydrous THF comes into contact with a silicone-based polymer, swelling occurs rapidly due to THF, and water can rapidly penetrate into the hydrophobic silicone-based polymer. Assuming that the separation performance may vary accordingly, water was added instead of alcohol to evaluate the separation performance of the silicone-based polymer from the polymer of the mixed material. However, as can be seen in the results of Comparative Example 13, very poor separation performance was observed, and water could not be used as a solvent to replace the monohydric alcohol, which is essential as a component of the mixed solvent according to the present invention.

[0289] Referring to a prior non-patent literature (Anal. Chem. 2003, 75, 6544) that presented the affinity of solvents for silicone-based polymers, ethyl acetate is an organic solvent with high polarity (μ (dipole moment) = 1.8 D) and relatively low swelling degree. In addition, since it has a functional group that can form a mutual hydrogen bond with silicone-based polymers, it is a compound that can interfere with or weaken the hydrogen bond between silicone-based polymers and alcohol. Referring to the case of Comparative Example 14 in which ethyl acetate was replaced with an organic solvent, the separation rate of silicone-based polymers was observed to be somewhat poor at 43% or less.

[0290] Unlike ethyl acetate, acetone has a structure in which two alkyl groups are bonded by a carbonyl group (C=O), and can only exhibit weak interactions with the siloxane bonds of silicone polymers. This is expected to not significantly interfere with the change in the properties of the polymer surface due to the formation of hydrogen bonds between the silicone polymer and alcohol as shown in Fig. 1. Referring to Example 22, in which acetone was actually applied as an organic solvent, a very dramatic separation effect of the silicone polymer was observed, unlike in Comparative Example 14, which used ethyl acetate.

[0291] Example 23 used dichlorobenzene as the organic solvent, which, similar to DCM, has a halogen element directly bonded to a hydrocarbon, but the hydrocarbon has an aromatic ring structure. When dichlorobenzene was used to form a mixed solvent and applied to the separation of silicone polymers, it exhibited separation performance similar to that of DCM (Example 1). The results of Example 23 clearly demonstrate that dichlorobenzene can also be adopted as a very effective organic solvent in the composition of mixed solvents.

[0292] Meanwhile, referring to the results of Example 24, in which separation of silicone polymers was performed using toluene as an organic solvent, low polarity and monocyclic aromatic hydrocarbon compounds also showed excellent effects as organic solvents for polymer swelling. In particular, when toluene was used as an organic solvent, it was observed that very fast and dominant separation of silicone polymers occurred within 30 minutes during the experiment. Toluene is widely known as a good solvent for effectively swelling not only silicone polymers but also various polymer materials. When toluene, which has an excellent swelling effect, was used as an organic solvent, separation was performed without adding an activator (Comparative Example 15) or without adding alcohol (Comparative Example 16), but very poor separation performance was observed in both cases. The comparative results of Example 24, Comparative Example 15, and Comparative Example 16 clearly illustrate that if even one of the constituent requirements of the composition according to the present invention is not met, the performance for separating a silicone-based polymer is not exhibited at all.

[0293] The results of Example 25, which used ethylbenzene, another monocyclic aromatic hydrocarbon compound, as an organic solvent, showed that it was very effective in separating silicone-based polymers, similar to Example 24, which used toluene. Example 26 shows the results of applying anisole, in which a methoxy group is substituted on the aromatic hydrocarbon ring, to a mixed solvent composition with ethanol for the separation of silicone-based polymers from a polymer material of mixed materials. As in the case of monocyclic aromatic hydrocarbon compounds, effective performance as an organic solvent for forming a mixed solvent was observed.

[0294]

[0295] <Optimal temperature range for separation of silicone polymers>

[0296] According to the present invention, these were conducted to determine useful temperature conditions for separating a silicone-based polymer from a waste polymer material of a mixed material in which a silicone-based polymer is coated on PET fiber by forming a mixed solvent and adding an activator.

[0297]

[0298] [Example 27]

[0299] Separation of the polymer material was performed in the same manner as in Example 1, except that the contact temperature of the silicone polymer material and the liquid mixture (mixed solvent and activator) was maintained at 10°C.

[0300]

[0301] [Example 28]

[0302] Separation of the polymer material was performed in the same manner as in Example 1, except that the contact temperature of the silicone polymer material and the liquid mixture (mixed solvent and activator) was maintained at 25°C.

[0303]

[0304] [Example 29]

[0305] Separation of the polymer material was performed in the same manner as in Example 1, except that the contact temperature of the silicone polymer material and the liquid mixture was maintained at 30°C.

[0306]

[0307] [Example 30]

[0308] Separation of the polymer material was performed in the same manner as in Example 1, except that the contact temperature of the silicone polymer material and the liquid mixture (mixed solvent and activator) was maintained at 50°C.

[0309]

[0310] [Example 31]

[0311] Separation of the polymer material was performed in the same manner as in Example 1, except that the contact temperature of the silicone polymer material and the liquid mixture (mixed solvent and activator) was maintained at 60°C.

[0312]

[0313] When the temperature of the mixed solvent in contact with the polymer material of the mixed material was heated to a temperature equal to or higher than the boiling point of the alcohol, the separation of the silicone polymer proceeded very rapidly. However, under some conditions where low-boiling-point alcohols are used at high temperatures exceeding 100℃, vapor pressure can be generated. This can lead to the disadvantage of having to perform the separation under high-pressure conditions in a pressurized vessel when using a closed system during the separation process. When the temperature is set low, the separation rate of the silicone polymer may be somewhat slower. However, if there is no limitation to the separation rate of the silicone polymer after long-term exposure, the low-temperature separation process may be more advantageous in terms of energy management.

[0314] Table 5 shows the effect of separation temperature on the separation rate when dissolving and separating a silicon-based polymer from a polymer material of a mixed material by forming a mixed solvent according to the present invention.

[0315] Example 1 was performed using the same compound but exposed to different temperature conditions. The separation efficiency was 100% in all cases, with separation occurring quickly even when the temperature varied from 60°C to 10°C. However, it was observed that the rate of PET decomposition decreased significantly as the temperature decreased. This means that the rate of PET decomposition is greatly affected by temperature, and that a method of performing material separation at low temperatures can be utilized as a useful means to completely separate silicone-based polymers while minimizing PET decomposition.

[0316]

[0317] <Method for Separating Silicon-Based Polymers Without Supplying Thermal Energy>

[0318] According to a method according to one configuration example of the present invention, an environment was created in which only a silicone-based polymer could be selectively separated quickly and efficiently from a polymer material comprising a composite of PET fibers and a silicone-based polymer without providing external heat. The examples below observe the separation rate of a silicone-based polymer through contact with a polymer material of a composite material after forming an activator and a mixed solvent without providing any external heat.

[0319]

[0320] [Example 32]

[0321] Separation of the polymer material was performed in the same manner as in Example 20, except that no external heat was applied (performed at room temperature), the contact time between the silicone polymer material and the liquid mixture was maintained for 3 hours, and 156 mmol (5.00 g) of methanol was used instead of ethanol.

[0322]

[0323] [Example 33]

[0324] The polymer material separation was performed in the same manner as in Example 32, except that 156 mmol (11.56 g) of diethyl ether was used instead of THF as the organic solvent and 156 mmol of ethanol was used instead of methanol.

[0325]

[0326] [Example 34]

[0327] The polymer material separation was performed in the same manner as in Example 32, except that 156 mmol (14.37 g) of toluene was used instead of THF.

[0328]

[0329] [Example 35]

[0330] The separation of polymer material was performed in the same manner as in Example 33, except that 156 mmol (14.37 g) of toluene was used instead of diethyl ether.

[0331]

[0332] [Example 36]

[0333] The polymer material separation was performed in the same manner as in Example 33, except that 156 mmol (13.44 g) of hexane was used instead of diethyl ether.

[0334]

[0335] Table 6 shows the results of comparing the separation rates of silicone-based polymers by forming a combination of activators and mixed solvents that were observed to have excellent separation speed and performance among the examples discussed above, and then contacting the polymer material of the mixed material for a relatively short period of time (2 or 3 hours) without providing any external heat energy.

[0336] In Example 32, in which potassium hydroxide was added to a mixed solvent composed of methanol and THF and contact was made with a polymer material of mixed material, most of the silicone-based polymer material was separated from the composite material within 3 hours.

[0337] In another system that does not use external heat energy, in the case of Example 33, which consists of a mixed solvent of ethanol and ether, the silicone polymer was completely separated within 2 hours.

[0338] In addition, a mixture prepared by adding a monohydric alcohol having a short-chain alkyl group as a composition of a mixed solvent, adding an aromatic compound (Examples 34 and 35) or a linear alkane hydrocarbon compound (Example 36), and then further adding potassium hydroxide as an activator resulted in the separation of a silicone polymer very quickly without the need for external heat supply.

[0339]

[0340] <Separation process of silicon-based polymers from composite polymers>

[0341] [Example 37]

[0342] As a composite polymer with a silicone polymer, 10 g of a waste airbag fiber (PDMS 23.9 wt%) was prepared by coating polydimethylsiloxane (PDMS) on a polyester polymer fiber, and the composition was prepared by mixing 37.70 g of anhydrous ethanol, 72.30 g of hexane, and 0.85 g of KOH.

[0343] The above-mentioned prepared composition was placed in a round-bottom flask, heated, and when the temperature of the liquid mixture was maintained at a constant 30°C, 10 g of the above-mentioned waste airbag fiber was brought into contact with it and completely immersed, and then stirred at 500 rpm for 20 minutes at 30°C to dissolve polydimethylsiloxane (PDMS), and then filtered using a glass fiber filter having a pore size of 2 μm to separate the polyester polymer fiber.

[0344] The filtrate from which the polyester polymer fibers were separated was transferred to a round flask, and a portion of the solvent was removed using a rotary evaporator. During the evaporation process, the flask containing the filtrate was placed in a water bath maintained at a temperature of 50°C, and the filtrate was evaporated under a vacuum of 265 mbar for 0.5 h. A separate cold trap maintained at a temperature below -50°C was installed at the outlet of the rotary evaporator to minimize external solvent loss due to the vacuum. The evaporated solvent was condensed and placed in a container (140 in Fig. 9) of a known mass for quantitative analysis. At this time, the solution that did not evaporate remained in the round flask, and polydimethylsiloxane (PDMS) was observed to have precipitated as a solid.

[0345] Afterwards, the high boiling point solution in which the polydimethylsiloxane (PDMS) was precipitated was filtered through a PTFE filter with a pore size of 0.45 μm, and polydimethylsiloxane (PDMS) was obtained as a solid, and the filtrate was placed in a flask (150 in Fig. 9) with a mass of alcohol in advance and quantified.

[0346] In addition, the separated polyester polymer fiber and polydimethylsiloxane (PDMS) were washed twice with an excess of distilled water maintained at 20°C or lower, and then additionally washed 3 to 5 times with ethanol, and then placed in a vacuum dryer maintained at 60°C under vacuum (≤ 2 mmHg) and dried for 12 hours or more to obtain the separated polyester polymer fiber and polydimethylsiloxane (PDMS), respectively.

[0347] The hexane recovered as a distillate (140 in FIG. 9) was 61.39 g, and the hexane recovered as a filtrate (150 in FIG. 9) was 4.28 g, so a total of 65.67 g was recovered, which is approximately 91% of the initial hexane amount of 72.3 g. The ethanol recovered as a distillate (140 in FIG. 9) was 13.55 g, and the ethanol recovered as a filtrate (150 in FIG. 9) was 22.92 g, so a total of 36.47 g was recovered, which is approximately 97% of the initial ethanol amount of 37.7 g. KOH was also introduced into the filtrate (150 in FIG. 9) and 0.82 g was recovered, which is approximately 96% of the initial KOH amount of 0.85 g. Considering the small scale in the above example and the amount lost, it can be seen that almost all of it can be recovered and used in actual commercial process applications. The lost material was replenished and new mixed polymer raw materials were added to repeat the separation of the silicone polymer more than five times, and it was found that the total mass of the silicone polymer removed through the second filtration process (130 in Fig. 9) was collected after discharge at an average mass of more than 96.7% of the mass of the silicone polymer in the mixed polymer added.

[0348] While the present invention has been described above with reference to the attached drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible. Accordingly, the technical protection scope of the present invention is defined by the following claims and their equivalents, and is not limited to the specific embodiments described herein.

Claims

1. A composition for separating a silicone polymer from a polymer of mixed material including a silicone polymer and a polymer having an ester functional group, The above composition for separating a silicon-based polymer comprises at least one alkali metal salt compound selected from the group consisting of alkali metal hydroxide salt, alkali metal alkoxide salt, alkali metal carbonate and alkali metal bicarbonate; monohydric alcohols; and A composition for separating a silicon-based polymer, characterized in that it comprises an organic solvent that causes swelling of a silicon-based polymer.

2. In paragraph 1, The above monohydric alcohol is a straight-chain alcohol or branched alcohol having 1 to 12 carbon atoms, A composition for separating a silicon-based polymer, characterized in that the organic solvent is at least one selected from among an ether in which hydrocarbons are linked to each other by oxygen, a ketone in which alkyl groups are bonded to a carbonyl group (C=O), a monocyclic aromatic compound substituted or unsubstituted by an alkyl group, an organic solvent in which at least one halogen element is directly bonded to carbon of a hydrocarbon, and an alkane compound having 5 to 30 carbon atoms.

3. In paragraph 1, A composition for separating a silicon-based polymer, characterized in that the alkali metal salt compound is at least one selected from the group consisting of KOH, K2CO3, NaOH, CH3OK, CH3ONa, C2H5OK, C2H5ONa, KHCO3, Na2CO3, and NaHCO3.

4. In paragraph 1, A composition for separating a silicon-based polymer, characterized in that the alkali metal salt compound is contained in a range of 0.01 wt% to 20 wt% based on the total weight of the composition.

5. In paragraph 1, A composition for separating a silicon-based polymer, characterized in that the organic solvent is at least one selected from the group consisting of methyl ethyl ether, diethyl ether, methyl phenyl ether, ethyl phenyl ether, furan, pyran, oxetane, tetrahydrofuran (THF), tetrahydropyran (THP), acetone, methyl ethyl ketone (MEK), diethyl ketone (DEK), methyl propyl ketone, methyl isobutyl ketone (MIBK), alkoxy benzene, chloromethane, dichloromethane, chloroform, tetrachloromethane, chlorobenzene, dichlorobenzene, benzene, toluene, xylene, ethylbenzene, styrene, pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane.

6. A method for separating a silicon-based polymer from a polymer of a mixed material comprising a silicon-based polymer and a polymer of an ester functional group, characterized by comprising a step of contacting a composition for separating a silicon-based polymer, comprising at least one alkali metal salt compound selected from the group consisting of alkali metal hydroxide salts, alkali metal alkoxide salts, alkali metal carbonates, and alkali metal bicarbonates; monohydric alcohols; and an organic solvent that causes swelling of the silicon-based polymer, with a polymer of a mixed material comprising a silicon-based polymer and a polymer of an ester functional group, thereby selectively dissolving and separating the silicon-based polymer from the polymer of the mixed material.

7. In paragraph 6, A method for separating a silicone polymer from a polymer of a mixed material including a silicone polymer and a polymer having an ester functional group, characterized in that the above contact is performed at 10°C to 100°C.

8. In paragraph 6, A method for separating a silicone polymer from a polymer of a mixed material comprising a silicone polymer and a polymer having an ester functional group, characterized in that after the above contact step, the method further comprises a step of purifying the separated polymer having an ester functional group and / or a silicone polymer by at least one method selected from the group consisting of filtering, washing, distillation, drying, and extraction.

9. In paragraph 6, A method for separating a silicone-based polymer from a polymer of a mixed material comprising a silicone-based polymer and a polymer having an ester functional group, characterized in that after the above contact step, the method further comprises a step of recovering the polymer having a separated ester functional group as a monomer through a depolymerization reaction.

10. In paragraph 6, A method for separating a silicon-based polymer from a polymer of a mixed material comprising a silicon-based polymer and a polymer having an ester functional group, characterized in that part or all of the alkali metal salt and organic solvent are recovered and reused.

11. In a process for separating a silicone polymer from a polymer of mixed material including a polymer having an ester functional group and a silicone polymer, (a) a step of adding a composition for separating a silicone polymer to a polymer of a mixed material including a polymer having an ester functional group and a silicone polymer, thereby selectively dissolving the silicone polymer from the polymer of the mixed material; (b) a step of filtering the mixed solution in which the silicone polymer is dissolved in the step (a) to separate the polymer having an ester functional group; (c) a step of removing at least a portion of the solvent from the filtrate filtered in step (b) to precipitate a silicone polymer; (d) a step of filtering the solution in which the silicon-based polymer is precipitated in the step (c) to separate the silicon-based polymer; (e) a step of recycling the solvent removed in step (c) and the filtrate filtered in step (d) as a composition for separating a silicone-based polymer in step (a); A process for separating a silicone polymer from a polymer of mixed material comprising a polymer having an ester functional group, characterized in that it includes a silicone polymer.

12. In paragraph 11, The above silicone polymer separation composition is, A process for separating a silicone polymer from a polymer of mixed material comprising a polymer having an ester functional group and a silicone polymer, characterized in that the polymer comprises an alkali metal salt compound, monohydric alcohols, and an organic solvent that causes swelling of the silicone polymer.

13. In paragraph 12, A process for separating a silicone-based polymer from a polymer of a mixed material including a polymer having an ester functional group and a silicone-based polymer, characterized in that the removal of the solvent in the above step (c) is carried out through evaporation.

14. In paragraph 11, Step (e) above, A process for separating a silicone polymer from a polymer of a mixed material comprising a polymer having an ester functional group and a silicone polymer, characterized in that the solvent removed in step (c) and the filtrate filtered in step (d) are recycled to a predetermined temperature through a heat exchanger as a composition for separating a silicone polymer in step (a).

15. In paragraph 11, Step (a) above, A process for separating a silicone polymer from a polymer of mixed material comprising a polymer having an ester functional group and a silicone polymer, characterized in that the process is performed at a temperature of 10°C to 100°C.

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