KR20170011986A - Method and composition for depolymerization of cured epoxy resin materials - Google Patents

Abstract

The present invention relates to a composition including a reactive solvent and a compound represented by chemical formula, XOmYn. In the chemical formula, X is a hydrogen, an alkali metal, or an alkali earth metal. Y is halogen. Also, m satisfies 1 <= m <= 8, and n satisfies 1 <= n <= 6. According to the reactive solvent, X is disassociated from XOY, and an epoxy resin hardened material can be depolymerized by using a composition in which a Y radical can be provided. Accordingly, an epoxy resin hardened material can be very simply and rapidly depolymerized at 200C or less, more preferably, at 100C or less, and process costs and consumption energy can be saved. Moreover, a reaction system using an organic solvent as a main solvent can be replaced, and thus a contamination problem caused when the organic solvent is used as a separate contaminant can be resolved. Thus, environmental contamination and pollution can be minimized. Moreover, even when a reaction system using an organic solvent as a main solvent is not used, efficiency in depolymerization can be improved. Furthermore, an epoxy resin hardened material which is relatively difficult to be decomposed can be easily decomposed. In addition, the degradation of properties of a filler collected after an epoxy resin hardened material is decomposed is prevented, so a recycled filler having excellent properties can be obtained.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a composition for depolymerization of a cured epoxy resin,

More particularly, the present invention relates to a method for depolymerizing an epoxy resin cured product, a composition used therefor, a method for separating a filler from an epoxy resin cured product, a filler obtained therefrom, and the like will be.

An epoxy resin is a thermosetting resin composed of a network polymer formed by ring-opening of an epoxy group, which is generated when an epoxy monomer having two or more epoxy groups in a molecule is mixed with a curing agent. Epoxy resin has excellent resistance to chemical components, durability and low volume shrinkage during curing, and is used as a highly functional raw material which is indispensable in all industries such as adhesives, paints, electronics / electrical engineering, and civil engineering / construction.

In the field of composite materials, which is becoming a major issue in recent years, epoxy resins are used in various fields such as aerospace, information and communication technology, and new energy fields in combination with various filler materials, thereby increasing demand worldwide. In particular, carbon fiber reinforced plastic (CFRP), which is made by mixing with carbon fibers, is widely used as a key material in automotive and aerospace fields because of its light weight and outstanding physical properties and durability. In addition, epoxy resins are widely used to make higher performance materials by mixing with other polymeric resin materials.

Epoxy resins form a three-dimensional network crosslinked structure after curing, which has very strong properties in chemicals. This has the advantage of imparting excellent durability and corrosion resistance to the material, but it also has the disadvantage that it is very difficult to process and recycle used materials.

As a result, most of the epoxy resin cured products are currently being treated by landfill, which is economically wasted and may cause serious environmental pollution.

Recently, as the amount of composite material of epoxy resin and filler is gradually increased, studies for selectively decomposing epoxy resin have been actively carried out in order to effectively separate filler materials which are relatively expensive compared to epoxy resin.

Currently, pyrolysis is the most commonly used method for decomposing epoxy resins and separating filler materials. For example, in the case of carbon fiber reinforced plastic (CFRP) using carbon fiber as a filler material, Japanese companies such as Toray, Teijin, and Mitsubishi are handling and recycling around 1,000 tons of pyrolysis annually. However, in order to separate carbon fibers through pyrolysis process, it is necessary to pre-process CFRP mechanically beforehand. In the process of crushing CFRP to several millimeters, carbon fibers may be crushed, The carbon fibers are adversely affected due to their short lengths. In addition, the pyrolysis process requires a high temperature of 500 ° C or more. At such a high temperature, combustion of an organic compound causes generation of harmful substances such as dioxins.

Therefore, several chemical decomposition methods have been studied to efficiently decompose epoxy resins at lower temperatures.

For example, when decomposing an epoxy resin under a supercritical or subcritical fluid, the epoxy resin cured product can be efficiently treated at a temperature lower than the pyrolysis temperature by about 250 to 400 ° C. The use of this method has the advantage that the characteristics of the recovering filler material are comparatively less than that of the pyrolysis method.

However, according to the results of the studies of the present inventors, since the method still requires a high temperature and a high pressure of 10 atm or more, there is a restriction that the economical efficiency is not high since a special process facility capable of enduring such conditions is required.

On the other hand, studies for decomposing an epoxy resin under more general and mild process conditions are also under way, but it is difficult to dissolve epoxy resins such as epoxy resins cured with a polyfunctional epoxy resin, an acid anhydride curing agent or an aromatic diamine curing agent There is a disadvantage in that it does not dissolve the various epoxy resin cured products, and the reaction time is long and the reaction energy is large. In addition, there are still problems such as the use of various organic solvents which are harmful to the human body as the main solvent of the reaction system.

Particularly, there are many known conventional techniques in which an organic solvent is used as a main solvent for decomposing an epoxy resin.

For example, an electrolytic solution containing an alkaline metal is added and an organic solvent is added to depolymerize the substrate by pulsed printing (Patent Document 2).

Further, there is also disclosed a technique in which an epoxy resin is subjected to pulverization and acid treatment, and then treated with an organic solvent and an oxidizing agent in a sealed reaction vessel (Patent Document 3).

Further, it has been disclosed that an epoxy resin is decomposed using hydrogen peroxide and acetone (Non-Patent Document 2)

Further, a technique of treating an epoxy resin composite material with a treatment liquid containing an alkali metal compound and an organic solvent from which moisture has been removed is disclosed (Patent Document 4).

Further, it has been disclosed that an epoxy resin prepolymer is brought into contact with a non-flowable organic solvent having a dipole moment of 3.0 or more to dissolve the epoxy resin prepolymer in a solvent (Patent Document 5).

Also disclosed is an organic solvent containing furan-2-carbaldehyde as an extraction solvent or a cracking solvent for separating carbon fibers from CFRP (Patent Document 6).

These techniques describe that epoxy can be decomposed with an organic solvent under mild conditions at relatively low temperatures.

However, these techniques are an organic solvent reaction system in which the organic solvent itself is used as a main means for dissolving the epoxy resin, and the organic solvent itself has a substantial limitation to solve the contamination problem due to the organic solvent . In addition, there are applicability problems that are difficult to apply to epoxy resin, which is difficult to decompose, or it takes a lot of energy to react, which is still unsatisfactory in terms of reaction efficiency.

Korean Patent Application Publication No. 2002-66046 Korean Patent Application Publication No. 2011-0113428 Chinese Patent No. 102391543 Japanese Patent Application Laid-Open No. 2005-255899 Japanese Patent Application Laid-Open No. 2013-107973 U.S. Patent Application Publication No. 2014-0023581

Mater. Res. Bull. 2004, 39, 1549 Green Chem., 2012, 14, 3260

In an exemplary embodiment of the present invention, in one aspect, the epoxy resin cured product can be very simply and quickly depolymerized under conditions of, for example, 200 ° C or less, more preferably 100 ° C or less, And to provide a composition for use in the depolymerization, and a depolymerization product obtained using the composition.

In an exemplary embodiment of the present invention, in another aspect, an organic solvent reaction system, which is a reaction system using an organic solvent as a main solvent, can be substituted, thereby solving the problem of contamination due to the organic solvent acting as a separate source Which is capable of minimizing environmental pollution and pollution, and a composition used therefor, and a depolymerization product obtained by using the composition.

In an exemplary embodiment of the present invention, in another aspect, there is provided a depolymerization method of an epoxy resin capable of increasing depolymerization reaction efficiency of an epoxy resin cured product without using an organic solvent reaction system which is a reaction system using an organic solvent as a main solvent And compositions used therefor, and depolymerization products obtained therefrom.

In an exemplary embodiment of the present invention, in another aspect, there is provided a method of depolymerizing an epoxy resin capable of easily decomposing an epoxy resin cured product which is relatively difficult to decompose, a composition used therefor, and a depolymerization product obtained using the same I want to.

In an exemplary embodiment of the present invention, in another aspect, there is provided a method for recovering a filler from an epoxy resin cured product, which is capable of obtaining a recycled filler having excellent characteristics by preventing degradation of the characteristics of the recovered filler after decomposition of the epoxy resin cured product , And to provide the filler obtained thereby.

In an exemplary embodiment of the present invention, there is provided a depolymerization composition of an epoxy resin cured product, wherein X is a hydrogen atom, wherein n is 1 &lt; = n &lt; = 6, and a reaction solvent, wherein X in the reaction solvent can be dissociated from X and Y radicals can be provided. .

In an exemplary embodiment of the present invention, there is provided a method of depolymerizing an epoxy resin cured product, wherein the epoxy resin cured product is depolymerized using the epoxy resin cured product solution polymerization composition.

In exemplary embodiments of the present invention, there is provided a depolymerization product of an epoxy resin cured product, wherein the product comprises a CY (Y is halogen) bond bonded to Y on carbon .

In an exemplary embodiment of the present invention, there is provided a method of separating a filler from an epoxy resin cured product, the method comprising: depolymerizing an epoxy resin cured product using the epoxy resin cured product solution polymerization composition; And obtaining a filler from the depolymerized epoxy resin cured product, and a method for separating the filler from the epoxy resin cured product and a separate filler therefrom.

According to the exemplary embodiments of the present invention, depolymerization of the epoxy resin cured product can be processed very simply and quickly under the conditions of, for example, 200 ° C or lower, more preferably 100 ° C or lower, and the process cost and energy required can be reduced have. In addition, it is possible to replace the reaction system using an organic solvent as a main solvent, thereby solving the problem of contamination due to the organic solvent acting as a separate contaminant, thereby minimizing environmental pollution and pollution. Further, the depolymerization reaction efficiency can be improved without using a reaction system using an organic solvent as a main solvent. In addition, epoxy resin cured products which are relatively difficult to decompose can be easily decomposed. Further, deterioration of the properties of the filler recovered after decomposition of the epoxy resin cured product can be prevented, and a recycled filler excellent in characteristics can be obtained.

Fig. 1 is a photograph of CFRP before depolymerization and carbon fiber recovered as a result of Example 1 in Example 1 of the present invention. Fig.
2 is a photograph of the change in aqueous sodium hypochlorite solution over time in Example 1 of the present invention.
3 shows the results of measurement of the pH of the sodium hypochlorite aqueous solution, which is the reaction system of Example 1 of the present invention, and the aqueous nitric acid solution, which is the reaction system of Comparative Example 3, respectively.
4 is a photograph of the change of nitric acid aqueous solution over time in Comparative Example 3 of the present invention.
5 is a graph comparing the results obtained by measuring the tensile strengths of the carbon fibers (raw material carbon fibers) used in the CFRP of Example 1 of the present invention and the carbon fibers obtained as a result of Example 1. Fig.
6 shows the results of structural analysis (NMR, GC, GCMS, FT-IR) of the products obtained in Example 1 of the present invention.
Fig. 7 shows X-ray photoelectron spectroscopic analysis results of graphene oxide before and after the depolymerization process in Example 10 of the present invention. FIG. 7A shows a case of raw graphene grains GO before the depolymerization process, and FIG. 7B shows a case of recycled GO grains recovered after depolymerization.
8 is a graph comparing the results obtained by measuring the tensile strengths of the glass fibers used in the epoxy resin cured product of Example 12 of the present invention and the glass fibers obtained as a result of Example 12. Fig.
9 is a graph showing the depolymerization ratio of the epoxy resin cured product according to the dielectric constant in each mixed solvent in Experiment 2 of the present invention.
10 is a graph showing the results of depolymerization of Example 1 when the radical-providing additive is added in Experiment 3 of the present invention.
11 is a graph showing the results of depolymerization of Comparative Example 1 when the radical-providing additive is added in Experiment 3 of the present invention.

Term Definition

As used herein, the epoxy resin cured product refers to various composite materials including an epoxy resin or an epoxy resin. In addition, epoxy resin cured materials are defined to include not only cured epoxy resins, but also some cured epoxy resins or intermediates produced during the curing reaction (so-called epoxy resin prepolymers or prepregs).

The composite material may include various fillers and / or various polymer resins. For reference, an epoxy resin is produced by a curing reaction between an epoxy compound having two or more epoxy groups in a molecule and a curing agent. The epoxy compound and the curing agent are not particularly limited. The epoxy compound may include, for example, a polyfunctional epoxy compound and the like. The curing agent includes, for example, an aromatic group or an aliphatic group, and may contain one or more groups selected from an amine group, an acid anhydride group, an imidazole group, and a mercaptan group in the molecule And so on.

In this specification, a filler means a filler material constituting an epoxy composite material together with an epoxy resin.

In the present specification, the polymer resin means a polymer resin constituting an epoxy resin composite material in addition to an epoxy resin.

In this specification, the reaction solvent is not limited to a specific phase. Thus, it may be primarily liquid, but it may include a gaseous phase. It may also include a supercritical phase.

In this specification, H ₂ O is mainly liquid water, but it is not limited to a liquid phase and may include a gaseous phase, and may also include a supercritical phase.

In this specification, the aqueous solution is a liquid phase, unless it indicates that it is in a gaseous state or a supercritical state. It is also a water-only solvent unless specifically indicated otherwise.

The term "organic solvent reaction egg" as used herein means a reaction system using an organic solvent as a main solvent for decomposition reaction of an epoxy resin cured product.

In this specification, H ₂ O reaction refers to a reaction system using H ₂ O as a main solvent for decomposition reaction of an epoxy resin cured product. This is in contrast to the organic solvent reaction system, and the H ₂ O-based reaction solvent is used in the depolymerization reaction. H ₂ O based on the reaction solvents may contain other solvents other than H ₂ O, but (i. E., Is applicable to the mixed solvent), but even when using such a mixed solvent dielectric constant is at least 65 or more, or preferably 70 or more, or 75 or more , Or 80 or more. A particularly preferred example is an H ₂ O based on the reaction solvent is constituted by H ₂ O alone (dielectric constant of water is approximately 80.2).

In the present specification, the depolymerization time means the depolymerization reaction time required to depolymerize all of the epoxy resin cured materials provided in the depolymerization reaction . Here, all of them are depolymerized means that substantially no residual epoxy resin cured product (solid matter) (residual epoxy resin ratio of 5% or less) is present. This can be measured, for example, by a thermal analyzer (TGA).

For reference, the decomposition rate (%) of an epoxy resin in a cured epoxy resin can be calculated as follows. That is, the decomposition ratio (%) = [(epoxy resin content in epoxy resin cured product - residual amount of epoxy resin after decomposition) / (epoxy resin content in epoxy resin composite material)] x100. The epoxy resin residual rate is 100% -decomposition.

In this specification, epoxy resin cured products which are relatively difficult to decompose refer to epoxy resin cured products which are relatively difficult to decompose and / or which use a curing agent. For example, the noble-rock resin of a multi-reflex type is an epoxy compound which is relatively difficult to decompose as compared with BPA. In addition, for example, the aromatic curing agent and the acid anhydride curing agent are relatively hard to decompose as compared with the aliphatic curing agent.

In this specification, the dielectric constant can be measured using a dielectric constant meter.

In the present specification, Y (Y = halogen) radical means Y having non-covalent hole electrons. For example, F, Cl, Br, I.

The term "depolymerization product" as used herein means that Y is bonded to a carbon (for example, benzene ring carbon) in a structural formula of a newly formed compound after depolymerization of an epoxy resin cured product, wherein the depolymerization product contains C-Y (Y is halogen) bond. Wherein Y is a compound XOmYn used in depolymerization wherein X is hydrogen or an alkali metal or alkaline earth metal and Y is halogen, m satisfies 1? M? 8 and n satisfies 1? N? 6 ). &Lt; / RTI &gt;

The term "pretreatment" as used herein means a treatment for widening the depolymerization reaction area prior to the depolymerization reaction of the epoxy resin cured product.

As used herein, the acidic composition means a composition having an acidity capable of performing chemical pretreatment.

In the present specification, the radical-providing additive means a compound which is additionally added to the radical production reaction system of XOmYn to provide a radical to promote the radical generation reaction of XomYn.

As used herein, a radical-containing compound means a compound having a radical and stable form before being added to the reaction system.

As used herein, a radical-generating compound means a compound that produces a radical in the reaction system.

Illustrative Implementations  Explanation

Hereinafter, exemplary embodiments of the present invention will be described in detail.

In an exemplary embodiment of the present invention, there is provided an epoxy resin cured material depolymerization composition, which comprises a compound represented by the formula XOmYn wherein X is hydrogen or an alkali metal or an alkaline earth metal, Y is halogen, m satisfies 1? M? 8, and n is a number satisfying 1 &lt; = n &lt; = 6), and a reaction solvent, wherein X is dissociated from XOmYn in the reaction solvent and Y radicals can be provided, and A method for depolymerizing an epoxy resin cured product with a composition is provided.

It has been surprisingly found by the present inventors that the epoxy resin cured product can be quickly and simply depolymerized in the combined composition of the specific compound and the reaction solvent (especially H ₂ O based reaction solvent) without using an organic solvent based reaction system It turned out. It is considered that the reaction solvent and the specific compound to be used together with the curing agent of the epoxy resin under low temperature mild conditions to increase the reaction efficiency. In addition, as will be described in detail below, it is considered that it is important to control the permittivity of the reaction solvent to a predetermined value or more in order to enable depolymerization of the epoxy resin cured product of the compound and increase depolymerization efficiency.

Although related mechanisms need to be further investigated, in the depolymerization according to exemplary embodiments of the present invention, X is preferentially dissociated in the reaction solvent (especially H ₂ O based reaction solvent) and finally the Y radicals [ Is believed to be generated, and it is considered that the Y radical (Y) binds to C of the epoxy resin cured product to form CY, and depolymerizes the epoxy resin cured product. Also, the dielectric constant of the reaction solvent should be controlled to be higher than a certain value in order to enable dissociation of X and generation of Y radicals and depolymerization reaction of the Y radicals of the epoxy resin cured product with low energy.

Thus, in exemplary embodiments of the present invention, the reaction solvent is selected to dissociate X from the XOmYn carrying the ionic bond, and also the Y radical must be able to be efficiently generated after X is dissociated. Further, in order to increase the reaction efficiency, the permittivity of the reaction solvent should be 65 or more, or 70 or more, or 75 or more, or 80 or more.

In an exemplary embodiment, such a reaction solvent is preferably a H ₂ O based reaction solvent. The dielectric constant of the H ₂ O-based reaction solvent used together with the epoxy resin cured product using the compound represented by the formula XOmYn affects the depolymerization reaction efficiency of the epoxy resin polymer. This is because, unlike the organic solvent in the organic solvent reaction system, the reaction solvent based on H ₂ O does not directly decompose the epoxy resin cured product but the dissociation of X and the generation of the Y radical from the compound XOmYn which depolymerizes the epoxy resin cured product And therefore, it is considered to be involved in the depolymerization reaction efficiency of the epoxy resin. The permittivity of the H ₂ O-based reaction solvent should be at least 65, or at least 70, or at least 75, or at least 80. When the dielectric constant is 65 or more, the reaction efficiency starts to increase sharply. Particularly preferred examples are H ₂ O is based on the reaction solvent geotinde consisting of H ₂ O only (water dielectric constant is about 80.2), H ₂ O based on the reaction solvent is H ₂ O When the sole epoxy resin cured product of the decomposition efficiency is dramatically increased (See Experimental Example 2 to be described later).

In contrast, in the organic solvent-based reaction system of the prior art described above, an epoxy resin cured product is directly dissolved using an organic solvent as a main solvent. Even if XOmYn is added to the organic solvent, X can not be dissociated and Y radicals can not be generated and can not be provided for depolymerization of the epoxy resin cured product. For example, in the case of NMP, the dielectric constant is 32 and XOmYn is not dissolved.

In this connection, the present inventors have examined the decomposition efficiency of the epoxy resin cured product according to the dielectric constant. As a result, the dissociation and reactivity of XOmYn, which is ion-bonded, differed in water and organic solvent, resulting in a difference in the decomposition efficiency of the epoxy resin cured product.

The reason for this is the difference in the solubility of the XOmYn compound in water and the organic solvent, and the difference in the radical production reaction.

First, in the case of the difference in solubility, a difference occurs in the solubility of the ion-binding substance XOmYn due to the difference in the polarity (that is, the dielectric constant) between water and the organic solvent. This is because the binding force between the dipole-ions of the solvent is larger than the ion-ion lattice energy of the ion-binding material, so that the ions can dissociate.

On the other hand, in the case of the radical generation reaction, the reaction formula in which XOmYn first generates radicals in water is as shown in the following Reaction Scheme 1. Therefore, it is necessary to allow the radical generating reaction of XOmYn to take place, and the equivalent amount of water such as XOmYn must be present so that the corresponding radical generating reaction can sufficiently take place, so that XOmYn can effectively generate radicals.

[Reaction Scheme 1]

Based on the above, it can be seen that it is necessary to use a solvent having a high dielectric constant, preferably H ₂ O-based solvent, which can effectively dissociate XOmYn and efficiently provide Y radicals. In the case of using the organic solvent contamination, and because the recycling problems in the organic solvent occurs, from an environmental aspect, H ₂ O-based solvent is preferred, and H ₂ O alone solvent to use in accordance with the organic solvent (a reaction solvent 100% by weight or 100% by volume of H ₂ O) is most preferably used.

Moreover, it is believed that the above-described Y (halogen) radicals are more likely to produce radicals because of the low hemolytic dissociation energy required for the generation of radicals. For example, the Y (halogen) radical has a low hemolytic dissociation energy value compared to the OH radical in the acetone and hydrogen peroxide system of the non-patent reference 2, for example. This means that when a Y (halogen) radical is employed, radicals can be efficiently formed at a smaller energy as compared with a substance such as hydrogen peroxide, so that depolymerization of the epoxy resin cured product can be performed with a lower energy. As a result, the epoxy resin cured product can be depolymerized at a lower temperature, and at the same time, the epoxy resin cured product which is difficult to dissolve in the past can be effectively depolymerized.

As described above, the depolymerization product is replaced with the Y radical by the Y radical generated by the reaction in which XOmYn is dissociated. That is, it has a C-Y bond.

This reaction mechanism can be described, for example, as shown in the following reaction formula.

[Reaction Scheme 2]

As in Scheme 1 above, for example, the depolymerization product may include one or more such as Product Example 1, Product Example 2, or Product Example 3, and the like. That is, the depolymerization product has a C-Y bond in which some carbons (e.g., some carbons of the benzene ring) bind Y.

Thus, in exemplary embodiments of the present invention, as a depolymerization product of an epoxy resin cured product, there is provided a depolymerization product of an epoxy resin cured product comprising C-Y (Y is halogen) bond to which Y is bonded to the carbon of the product. For reference, Experiment 1 to be described later shows the results of analyzing three examples of depolymerization products in which such C-Y bonds are formed, and the analysis result shows that the depolymerization products according to exemplary embodiments of the present invention have a C-Y bond.

When the epoxy resin cured product is depolymerized using the depolymerization composition of the epoxy resin cured product as described above, the cured product of the epoxy resin having a shortened life span can be reduced to less than 200 ° C, more preferably less than 100 ° C, Energy can be processed very simply and quickly. These results indicate that the reaction temperature is greatly reduced unlike the conventional thermal decomposition method (about 200 to 400 ° C).

In addition, when the reaction solvent and the compound are differently combined, for example, Comparative Example 1 (not dissolved) in which hydrogen peroxide water and acetone are mixed (Comparative Example 2) in which sodium hypochlorite is mixed with acetone (not dissolved) The reaction efficiency is remarkably higher than that in Comparative Example 3 (reaction time 12 hours) in which the dielectric constant is low or nitric acid aqueous solution is used. Furthermore, unlike the techniques using conventional organic solvent-based reaction systems, since H ₂ O based reaction systems are used, environmentally advantageous because organic solvents harmful to human bodies can be avoided.

Meanwhile, in the exemplary embodiments of the present invention, the filler material contained in the epoxy resin cured product can be easily separated and recycled as described above. The filler thus obtained can be prevented from degrading the characteristics of the filler even though it has undergone decomposition, which is very advantageous for recycling.

In an exemplary embodiment, X in the XOmYn is hydrogen or an alkali metal such as lithium, potassium, sodium, or an alkaline earth metal such as calcium or magnesium. In an exemplary embodiment, Y in the above XOmYn is a halogen element such as F, Cl, Br, I or the like.

In a non-limiting example, m, n may be a natural number within the range. However, it is not limited to the natural number, and may be a prime number, for example, in the case of forming a complex.

In a non-limiting example, in XOmYn, for example, when m is 1 and n is 1, HOF, HOCl, HOBr, HOI, NaOF, NaOCl, NaOBr, NaOI, LiOF, LiOCl, LiOBr, LiOI, KOF , KOCl, KOBr, KOI, and the like.

When m is 2 and n is 1, for example, HO ₂ F, HO ₂ Cl, HO ₂ Br, HO ₂ I, NaO ₂ F, NaO ₂ Cl, NaO ₂ Br, NaO ₂ I, LiO ₂ F, LiO ₂ Cl, LiO ₂ Br, LiO ₂ I, KO ₂ F, KO ₂ Cl, KO ₂ Br, KO ₂ I, and the like.

When m and n are each 2, it may be Ca (OF) ₂ , Ca (OCl) ₂ , Ca (OBr) ₂ , Ca (OI) ₂ or the like.

When m is 3 and n is 1, for example, HO ₃ F, HO ₃ Cl, HO ₃ Br, HO ₃ I, NaO ₃ F, NaO ₃ Cl, NaO ₃ Br, NaO ₃ I, LiO ₃ F, LiO ₃ Cl, LiO ₃ Br, LiO ₃ I, KO ₃ F, KO ₃ Cl, KO ₃ Br, KO ₃ I, and the like.

When m is 4 and n is 1, for example, HO ₄ F, HO ₄ Cl, HO ₄ Br, HO ₄ I, NaO ₄ F, NaO ₄ Cl, NaO ₄ Br, NaO ₄ I, LiO ₄ F, LiO ₄ Cl, LiO ₄ Br, LiO ₄ I, KO ₄ F, KO ₄ Cl, KO ₄ Br, KO ₄ I, and the like.

When m = 6 and n = 2, for example, MgO ₆ F ₂ , MgO ₆ Cl ₂ , MgO ₆ Br ₂ , MgO ₆ I ₂ , CaO ₆ F ₂ , CaO ₆ Cl ₂ , CaO ₆ Br ₂ , CaO ₆ I ₂ , SrO ₆ F ₂ , SrO ₆ Cl ₂ , SrO ₆ Br ₂ , SrO ₆ I ₂ , BaO ₆ F ₂ , BaO ₆ Cl ₂ , BaO ₆ Br ₂ , BaO ₆ I _{2 and the} like.

When m = 1 and n = 3, for example, NaOCl ₃ , And when m = 1 and n = 4, NaOCl ₄ And so on.

The maximum value of m for forming XOmYn is 8, for example MgO ₈ Cl ₂ , CaO ₈ Cl ₂ , SrO ₈ Cl ₂ , BaO ₈ Cl _{2 and the} like. In addition, the maximum value of n for forming XOmYn is when the 6 may be, for example, NaOCl _6.

In an exemplary embodiment, the H ₂ O-based solvent is particularly preferred as an aqueous solution (the reaction solvent is H ₂ O alone or, in the case of a liquid, water alone) as described above.

In an exemplary embodiment, when X is an alkali metal or alkaline earth metal in XOmYn, the pH condition of the depolymerization composition (or aqueous solution) is adjusted to a pH of at least 1, slightly acidic, or basic. It is considered that X (alkali metal or alkaline earth metal) is more easily decomposed into XOH or X (OH) ₂ in the H ₂ O-based reaction system by adjusting the pH condition.

In a non-limiting example, the pH of the depolymerization composition (or aqueous solution) is preferably from 1 to 14, more preferably from 8 to 14 in terms of reactivity.

In an exemplary embodiment, the depolymerization reaction temperature may be, for example, less than 250 DEG C (e.g., 20 DEG C or more and less than 250 DEG C), or 200 DEG C or less (e.g., 20 to 200 DEG C) Lt; 0 &gt; C).

In an exemplary embodiment, the H ₂ O based reaction solvent can be liquid, gaseous, and supercritical. The use of a liquid phase is simple and requires less reaction energy. In the embodiments of the present invention, it is possible to quickly depolymerize at a low temperature even if the liquid phase is used, but it is needless to say that the gas phase and the supercritical state can be intentionally used. When the supercritical state is set as described above, the reaction time can be further shortened, but the reaction apparatus and the process become complicated.

In an exemplary embodiment, it is preferable to further include a radical-providing additive in addition to the XOmYn in view of being able to further accelerate the depolymerization reaction of the epoxy resin cured product. As previously defined, a radical-providing additive refers to a compound that is additionally added to the radical-forming reaction system of XOmYn to provide a radical to facilitate the radical-generating reaction of XomYn.

Such a radical-providing additive may be a compound which itself has a radical before it is added to the reaction system, and which is in a stable form (referred to as a radical-containing compound) or a compound which generates a radical in the reaction system. A compound that generates a radical in the reaction system (referred to as a radical-generating compound) may be a compound that generates a radical through a chemical reaction or physical action.

In a non-limiting example, examples of such radical-providing additives include BPO (benzoyl peroxide), sodium percarbonate, Fremy salt [disodium nitrosodisulfonate], TEMPO [(2,2,6 , 6-tetramethyl-piperidin-1-yl) oxyl; (2,2,6,6-Tetramethyl-piperidin-1-yl) oxyl].

Of these, Fremy salts and TEMPO are radical-containing compounds having radicals themselves, and BPO, sodium percarbonate, and the like are compounds that generate radicals in the reaction system.

Specifically, the radical generation mechanism in the reaction system by, for example, sodium percarbonate can be described, for example, as shown in the following reaction formula.

[Reaction Scheme 3]

In the case of sodium percarbonate, as in [Reaction Scheme 3], a reactive species is formed in the reaction system by water in the reaction system, and the peracid reaction species can be present as carbonic acid radicals and hydroxyl radicals in the reaction system.

The radical thus generated promotes the radical generation reaction from XOmYn. That is, as compared with the reaction in which HOmYn (refer to the reaction formula 1 described above with respect to HOmYn) becomes three radicals as in the following reaction formula 4, since a radical is already present before the reaction, a stable compound is generated after the reaction, So that the equilibrium of the left-handed person is further moved to the right.

[Reaction Scheme 4]

On the other hand, in the case of BPO, two phenyl radicals are generated by the heat (Reaction Formula 5), and in the case of the premitium salt and TEMPO, the compound itself exists in a radical form (Chemical Formula 1 and Chemical Formula 2). Thus, as in the case of sodium percarbonate, it is additionally added to the radical production reaction system of XOmYn to provide a radical to promote the radical generation reaction of XOmYn.

[Reaction Scheme 5]

[Chemical Formula 1]

(2)

As described above, the radical-generating reaction of XOmYn is promoted, so that the depolymerization reaction of the epoxy resin cured product is promoted. The rate equation for the decomposition of carbon-carbon bonds using radicals is exponentially proportional to the concentration of radicals in the reaction system as shown in Equation 6 below, and this rate equation is also applied to the reactions of the embodiments of the present invention. Therefore, due to the above-mentioned radical-providing additive, the concentration of radicals in the reaction system is increased, and as a result, the reaction rate is increased, and the depolymerization reaction of the epoxy resin cured product can be promoted.

[Reaction Scheme 6]

In an exemplary embodiment, the radical-providing additive may comprise from 0.00001% to 99% by weight, preferably from 0.1% to 10% by weight based on 100% by weight of the total composition (reaction solvent + XO _m Y _n compound) have.

In an exemplary embodiment, a further pre-treatment may be performed to increase the reaction surface area of the epoxy resin cured product before providing the epoxy resin cured product to the polymerization reaction. As described above, according to the exemplary embodiments of the present invention, the reaction time can be significantly reduced at a low temperature without performing a separate pretreatment. However, such a reduced reaction time can be further reduced through pretreatment for increasing the reaction surface area . That is, through the above-described pretreatment, the reaction area of the epoxy resin cured product is increased so that the subsequent depolymerization reaction can occur more smoothly.

In an exemplary embodiment, the pretreatment may be one of physical pretreatment and chemical pretreatment, or a combination thereof.

In a non-limiting example, the physical pretreatment may be, for example, milling. The pulverizing method may be one or two or more selected from a dry pulverizing method and a wet pulverizing method and may be one or more selected from a hammer mill, a cutter mill, a flake crusher, a feather mill, a pin mill, an impact mill, And may be pulverized using one or more selected from the group consisting of planetary mill, hydro mill, and aquarizer. In an exemplary embodiment, the ground epoxy resin cured product may have a size of 1 to 10 cm.

In a non-limiting example, the chemical pretreatment may be to impregnate the acidic composition with an epoxy resin cured product (i.e., acid treatment).

In an illustrative non-limiting example, the acidic composition used in the impregnation method may have a pH of 5.0 or less, a temperature of 20-250 ° C, and may be added to the acidic composition after impregnation of the epoxy resin cured product to separation of the epoxy resin cured product May be 0.1 to 24 hours. The separated epoxy resin cured product is then washed.

In a non-limiting example, the acidic composition may be a gas phase composition consisting of, for example, one or more materials selected from the group consisting of air, nitrogen, argon, helium, water vapor. Also, the acidic composition may be prepared by dissolving the acidic composition in water, acetone, acetic acid, ethyl acetate, methyl ethyl ketone, N-methyl-2-pyrrolidone, N, N- dimethylformamide, N, N-dimethylacetamide, tetrahydrofuran, acetonitrile, t-butanol, n-butanol, n Propanol, i-propanol, ethanol, methanol, ethylene glycol, dimethyl sulfoxide, 1,4-dioxane, and the like. &Lt; RTI ID = 0.0 &gt; and / or &lt; / RTI &gt; The gas or liquid composition may be used alone or in combination. However, the use of an organic solvent in the gastric acid composition is not preferable from the environmental viewpoint.

In an exemplary embodiment, the epoxy resin cured material to be degraded may include various fillers and / or polymer resins.

In an exemplary embodiment, the filler may be a carbon fiber or other graphite, graphene, oxidized graphene, reduced graphene, carbon nanotubes, glass fibers, inorganic salts, metal particles, ceramic materials, monomolecular organic compounds, , Silicone resin, and the like.

In an exemplary embodiment, the polymeric resin is selected from the group consisting of acrylic resin, olefin resin, phenolic resin, natural rubber, synthetic rubber, aramid resin, polycarbonate, polyethylene terephthalate, polyurethane, polyamide, polyvinyl chloride, polyester, polystyrene, poly Acetal, acrylonitrile butadiene styrene, styrene acrylonitrile, and the like.

In an exemplary embodiment, the XOmYn compound may be 0.001-99% by weight, based on 100% by weight of the total composition (reaction solvent + XOmYn compound). In a non-limiting example, if the reaction solvent is, for example, an aqueous solution, the XOmYn compound may be included in an amount of 0.001 to 99% by weight based on the entire aqueous solution containing the XOmYn compound.

In an exemplary embodiment, the epoxy resin cured product may be 1 to 90 parts by weight based on 100 parts by weight of the depolymerization composition (reaction solvent + XOmYn compound). In a non-limiting example, when the reaction solvent is an aqueous solution, the epoxy resin cured product (e.g., CFRP) may be 1 to 90 parts by weight based on 100 parts by weight of the aqueous solution containing the XOmYn compound.

In an exemplary embodiment, the method may further comprise the step of preparing the XOmYn compound. The thus prepared XomYn is supplied to the epoxy resin cured product to perform chemical depolymerization.

In a non-limiting example, for example, when the XOmYn compound is, for example, HOY, a halogen (e.g., Cl, etc.) gas is bubbled into water to make an HOY aqueous solution and an epoxy resin cured product is added to the epoxy resin cured product .

That is, in a non-limiting example, when the compound is, for example, HOCl, a Cl ₂ gas may be bubbled into water to make an HOCl aqueous solution, and then an epoxy resin cured product such as CFRP may be added to perform depolymerization.

Alternatively, in a non-limiting example, the XomYn compound is XOY, wherein X is an alkali metal and Y is a halogen, and XY is electrolyzed in water to form an aqueous solution containing an XOY compound, To provide a depolymerization composition to the epoxy resin cured product.

That is, in a non-limiting example, when the compound is NaOCl, NaCl may be electrolyzed in water to form an aqueous solution containing NaOCl, followed by depolymerization by placing an epoxy resin cured product such as CFRP.

On the other hand, in a non-limiting example, the XomYn compound can be prepared through a chemical or physical reaction in a depolymerization reactor (depolymerization reaction system) of an epoxy resin cured product.

For example, in a non-limiting example, an aqueous solution of sodium hypochlorite (NaOCl) is produced in a depolymerization reactor through the mixing of an aqueous solution of sodium hydroxide (NaOH) and chlorine (Cl ₂ ) and depolymerization of the epoxy resin cured product.

On the other hand, exemplary embodiments of the present invention include: depolymerizing an epoxy resin cured product with a depolymerization composition comprising a XOmYn compound and a reaction solvent as described above; And obtaining a filler from the depolymerized epoxy resin cured product, for example, by filtration, extraction, or the like, and a filler obtained from the epoxy resin cured product thus obtained.

The filler separated and recovered from the epoxy resin cured product can prevent degradation of properties as compared with before the depolymerization process of the epoxy resin cured product, and accordingly, a recycled filler having excellent characteristics can be obtained.

For example, when the filler is a carbon fiber, degradation in properties such as tensile strength and elongation can be very small, for example, about 13% or less compared to the raw filler carbon fiber contained in the epoxy resin cured product . Regarding the carbon fiber recovered from the CFRP by the pyrolysis method, the tensile strength is lowered by about 15% or more as compared with the raw carbon fiber (Non-Patent Document 1). On the other hand, according to the embodiments of the present invention, when the depolymerization is performed, the carbon fiber can be recovered with very little deterioration of the tensile strength of the carbon fiber.

In an exemplary embodiment, the method may repeat the decomposition process by depolymerizing the epoxy resin cured product and then adding a new epoxy resin cured product to the remaining reaction solvent.

The product obtained by polymerizing the epoxy resin cured product according to the above method is an aqueous solution state of low viscosity, and there is no gel-like insoluble suspended matter, and the filler can be separated from the aqueous solution, for example, by filtration or extraction.

Hereinafter, specific embodiments according to exemplary embodiments of the present invention will be described in more detail. It should be understood, however, that the invention is not limited to the embodiments described below, but that various embodiments of the invention may be practiced within the scope of the appended claims, It will be understood that the invention is intended to facilitate the practice of the invention to those skilled in the art.

[Experiment 1]

In the following Examples, a water-only solvent was used as a reaction solvent. An aqueous solution (liquid phase) was used in other embodiments except for the aqueous solution in the gaseous state in Example 3, and the aqueous solution in Example 4 in the supercritical state. The permittivity of water is 80.2.

On the other hand, in Comparative Examples 1 and 2, a mixed solvent of water and acetone was used and the dielectric constant was about 44.

In Example 5, the amount of pulmonary CFRP was increased to 16 times that in Example 1. In Examples 6 to 9, the amount of pulmonary CFRP was increased to 10 times that of Example 1, and the amount of sodium hypochlorite aqueous solution Respectively.

In Example 7, pulverized CFRP was pulverized and then subjected to post-polymerization. In Example 8, the pulverized CFRP was subjected to acetic acid-impregnation and polymerized. In Example 9, the pulverized CFRP was pulverized and impregnated.

[ Example  One: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  &Lt; / RTI &gt; and separation of the filler (carbon fiber)

The epoxy resin cured product used in this Example 1 is a closed CFRP. The waste CFRP is composed of an epoxy resin cured product of bisphenol A containing diglycidyl ether type including halogen element and an aromatic curing agent containing aromatic amine group and carbon fiber. This CFRP is known to be very difficult to break down because it uses an aromatic curing agent.

0.1 g of the above-mentioned CFRP was added to 70 mL of a 2 mol / L sodium hypochlorite aqueous solution contained in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

FIG. 1 is a photograph of the CFRP before depolymerization used in Example 1 of the present invention and the carbon fiber recovered as a result of Example 1, and FIG. 2 is a photograph showing the change of aqueous sodium hypochlorite solution containing CFRP over time And FIG. 3 shows the results of measuring the pH of an aqueous sodium hypochlorite solution containing CFRP.

Table 1 shows the time at which decomposition of the epoxy resin was completed. The results of measurement of the viscosity of an aqueous solution of sodium hypochlorite obtained by filtering the carbon fibers using a Brookfield viscometer and the results of pH measurement are shown in Table 2, Table 3 shows the tensile strength and electrical conductivity of the carbon fiber. The details of the electrical conductivity change are also shown in Table 4.

After 6 hours, it was confirmed that the epoxy resin was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), and the carbon fibers in the aqueous solution were separated by filtration and dried.

In order to confirm that the Y-radical (Cl radical in Example 1) was substituted for the depolymerization product of Example 1 of the present invention to form a C-Y bond, analysis such as NMR was performed.

6 shows the results of structural analysis (NMR, GC, GCMS, FT-IR analysis) of various products obtained as a result of Example 1 of the present invention. 6A, 6A and 6C, respectively. FIG. 6A relates to product example 1, FIG. 6B relates to product example 2, and FIG.

Specifically, in Example 1, the carbon fiber was filtered, and the product in the form of an aqueous solution was extracted with dichloromethane and then dried to analyze the obtained solid mixture.

For the NMR analysis, a 600 MHz NMR spectrometer from Agilent Technologies was used and the hydrogen nuclide was measured using deuterated chloroform as a solvent.

For GC analysis, GC-2010 Plus instrument from Shimadzu was used and gas chromatography of the mixture was measured using dichloromethane as a solvent.

For the GC-MS analysis, a GCMS-QP2010 instrument from Shimadzu was used, and compounds with molecular weights between 30 and 350 were detected based on the GC results previously analyzed.

For the FT-IR analysis, a Nicolet iS 10 instrument from ThermoScientific was used, and a pellet was prepared using a solid mixture and potassium bromide, and then a 500 cm ^-1 to 4000 cm ^-1 wavenumber interval was measured.

As can be seen from FIG. 6, it was confirmed from the NMR, GC-MS and IR results that the presence of three kinds of compounds having C-Y bonds in common. Thus, it was found that the solid mixture (i.e., the depolymerization product of the epoxy resin cured product) contained the compounds having the C-Y bond.

[ Example  2: Hypochlorous acid (HOCl) aqueous solution Filler (graphene)  Decomposition of epoxy resin cured product and separation of filler (graphene)]

The cured product used in Example 2 was composed of epoxy resin and graphene produced by using a curing agent containing an epoxy compound of glycidyl ether type of cresol novolak and an aromatic amine group. This CFRP is also known to be difficult to decompose in general because it uses novolak epoxy compounds and aromatic curing agents.

0.1 g of the cured epoxy resin was added to 70 mL of a 2 mol / L hypochlorous acid aqueous solution contained in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 5.5 hours, it was confirmed that the epoxy resin was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), and the graphene in the aqueous solution was separated by filtration and dried.

The time at which the decomposition of the epoxy resin was completed is shown in Table 1, and the thermal conductivity of the graphene used in the epoxy resin cured product of Example 2 of the present invention and the graphene recovered as the result of Example 2 are shown in Table 3 .

[ Example  3: Gaseous Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  &Lt; / RTI &gt; and separation of the filler (carbon fiber)

0.1 g of the same CFRP as used in Example 1 was placed on a wire mesh above the pressure vessel containing 70 mL of 2 mol / L sodium hypochlorite aqueous solution, and the liquid inlet and the CFRP inlet of the pressure vessel were sealed and then heated to 120 DEG C Respectively. A gaseous aqueous solution of sodium hypochlorite was thus provided to the CFRP.

The time at which the CFRP decomposition was completed is shown in Table 1.

After 8 hours, it was confirmed that the CFRP was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), and water was injected from the upper part of the pressure vessel to decompose the epoxy resin The resulting product was dissolved and moved to the bottom of the pressurized vessel, and the carbon fibers remaining on the wire net were separated and dried.

[ Example  4: Supercritical  State Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  &Lt; / RTI &gt; and separation of the filler (carbon fiber)

0.1 g of the same CFRP as used in Example 1 was added to 70 mL of a 2 mol / L sodium hypochlorite aqueous solution contained in a batch type reactor equipped with a pressure gauge, and the reactor was sealed and then heated to 374 DEG C using an electric heating jacket . At this time, the pressure indicated on the pressure gauge was 221 bar.

After 1 hour, the reactor was cooled to room temperature, and it was confirmed whether or not the CFRP in the reactor was decomposed.

Table 1 shows the time for completing the decomposition of the epoxy resin by increasing the reaction time in an hour.

After confirming that the epoxy resin was completely depolymerized after 2 hours (it was confirmed that there was no epoxy resin residue through measurement of thermal gravimetric analyzer (TGA) after depolymerization), the carbon fiber inside the reactor was separated and dried.

[ Example  5: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  Epoxy resin Hardened  Decomposition and Of filler (carbon fiber)  detach : CFRP  Increase amount]

On the other hand, in this example, the same conditions as in Example 1 were used (i.e., 70 mL of 2 mol / L sodium hypochlorite aqueous solution was added and stirred at 70 DEG C) , 1.6g). After 12 hours, the decomposition of the epoxy resin was visually confirmed, and the carbon fibers in the aqueous solution were separated by filtration and dried. The time at which depolymerization is completed is shown in Table 1.

[ Example  6: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  (Carbon fiber): increase in the amount of CFRP]

In this case, 1.0 g of the used CFRP used in Example 1 (increased 10-fold compared to Example 1) was added to 100 ml of a 4 mol / L sodium hypochlorite aqueous solution contained in an open glass container, followed by stirring at 90 ° C. A pressurized reactor (autoclave) was not used.

After 8 hours, it was confirmed that the CFRP was completely depolymerized (after the depolymerization, it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA)), the carbon fiber in the aqueous solution was separated and dried.

The time at which depolymerization is completed is shown in Table 1. The results of measurement of tensile strength and electrical conductivity of the carbon fibers obtained as a result of Example 6 are also shown in Table 3.

[ Example  7: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  (Carbon fiber): depolymerization after CFRP pulverization]

The other conditions in Example 6 were the same, except that 1.0 kg of pulmonary CFRP was pulverized into 2.0 mm diameter pieces using a Barley Grinder Crusher manual grinder from Wellbom, China.

1.0 g of the cured epoxy resin cured product piece was added to 100 mL of a 4 mol / L sodium hypochlorite aqueous solution contained in an open glass container, followed by stirring at 90 ° C. A pressurized reactor (autoclave) was not used.

After 4 hours, it was confirmed that the CFRP was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermal gravimetric analyzer (TGA) after depolymerization), and the carbon fiber in the aqueous solution was separated and dried. The time at which depolymerization is completed is shown in Table 1.

[ Example  8: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  (Carbon fiber): depolymerization after impregnation with CFRP]

The other conditions in Example 6 were the same, except that 1.0 g of the pulmonary CFRP was added to 100 mL of 99% acetic acid and heated at 120 캜 for 30 minutes. The epoxy resin cured product was separated and washed with 20 mL of acetone.

The washed cured epoxy resin was added to 100 mL of a 4 mol / L sodium hypochlorite aqueous solution contained in an open glass container, followed by stirring at 90 ° C. A pressurized reactor (autoclave) was not used.

After 5 hours, it was confirmed that the epoxy resin cured product was completely polymerized (after the depolymerization, the epoxy resin residue was confirmed through the measurement of the thermogravimetric analyzer (TGA)), and the carbon fiber in the aqueous solution was separated and dried.

The time at which the depolymerization of the epoxy resin cured product is completed is shown in Table 1. Table 3 shows the tensile strength and electrical conductivity of the carbon fiber used in Example 8 of the present invention.

[ Example  9: Sodium hypochlorite ( NaOCl ) Aqueous solution CFRP  (Carbon fiber): CFRP pulverization and depolymerization after impregnation]

1.0 kg of the cured epoxy resin was crushed into pieces having an average diameter of 2.0 mm using a Micro Hammer Cutter Mill automatic grinder manufactured by Glen Creston, UK.

1.0 g of the cured epoxy resin cured product was placed in 100 mL of 99% acetic acid, heated at 120 ° C. for 30 minutes, filtered using an Advantec cellulose filter paper to separate the epoxy resin cured product, and washed with 20 mL of acetone.

1.0 g of the washed epoxy resin cured product piece was added to 100 mL of a 4 mol / L sodium hypochlorite aqueous solution contained in an open glass container, followed by stirring at 90 ° C. A pressurized reactor (autoclave) was not used.

After 3 hours, it was confirmed that the CFRP was completely depolymerized (after the depolymerization, it was confirmed that there was no epoxy resin residue by measurement of the thermogravimetric analyzer (TGA)), the carbon fiber in the aqueous solution was separated and dried. The time at which the depolymerization of the epoxy resin cured product is completed is shown in Table 1.

[ Example  10: Iodine acid ( HIO ₃ ) Aqueous solution Filler (graphene oxide)  Decomposition of epoxy resin cured product and separation of filler (graphene oxide)]

The cured product used in Example 10 was composed of an epoxy resin cured product and an oxidized graphene produced using a curing agent containing an epoxy compound of glycidylamine type and an acid anhydride group.

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L aqueous solution of iodic acid in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 5 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), and the graphene oxide in the aqueous solution was separated by filtration and dried . Table 1 shows the depolymerization time.

7 shows X-ray photoelectron spectroscopic analysis results of the graphene grains before and after the depolymerization process in Example 10 of the present invention. FIG. 7A is the case of the raw material oxide grains GO before the depolymerization process, and FIG. 7B is the case of the recovered oxidized grains (recycled GO). The results of X-ray photoelectron spectroscopy analysis are shown in Table 5 for the content of each bond and carbon and oxygen elements. From the results, it can be seen that there is almost no change in the characteristics of the graphene oxide before and after the decomposition process.

[ Example  11: perchloric acid ( HClO ₄ ) Aqueous solution Filler (carbon nanotube)  And decomposition of filler (carbon nanotube)]

The cured product used in Example 11 was prepared in the same manner as in Example 2 except that an epoxy resin cured product of glycidyl ether type cresol novolak and a curing agent containing an aromatic amine group, Respectively.

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L perchloric acid aqueous solution contained in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 3.5 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), the carbon nanotubes in the aqueous solution were separated by filtration and dried .

The time for completion of the decomposition of the epoxy resin is shown in Table 1 and the results of measuring the thermal conductivity of the carbon nanotubes used in the epoxy resin cured product of Example 11 and the resultant carbon nanotube obtained in Example 11 are shown in Table 3 Respectively.

[ Example  12: Bromic acid ( HBrO ₃ ) Aqueous solution Filler (glass fiber)  Decomposition of epoxy resin cured product and separation of filler (glass fiber)]

The cured product used in Example 12 was prepared by mixing an epoxy resin cured product obtained by using a curing agent containing an epoxy compound of glycidyl ether type of cresol novolak and an aromatic amine group and a cured product of an epoxy resin cured product of glass fiber .

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L aqueous solution of bromic acid in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 4.5 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (after the depolymerization, the epoxy resin residue was not found through the thermogravimetric analyzer (TGA)). The glass fiber in the aqueous solution was separated by filtration and dried. Table 1 shows the depolymerization time.

8 is a graph comparing the results obtained by measuring the tensile strengths of the glass fibers used in the epoxy resin cured product of Example 12 of the present invention and the glass fibers obtained as a result of Example 12. Fig. Table 3 shows changes in the tensile strength of the glass fiber before and after the decomposition process derived from the tensile strength measurement results. From this result, it can be confirmed that the characteristic change is small.

[ Example  13: Chlorite ( HClO ₂ ) Aqueous solution Filler (alumina)  Decomposition of epoxy resin cured product and separation of filler (alumina)]

The cured product used in Example 13 was composed of an epoxy resin cured product obtained by using a curing agent containing an epoxy compound of glycidyl ether type of cresol novolak and an aromatic amine group and alumina as used in Example 2 lost.

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L aqueous chlorine acid solution in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 5 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermal gravimetric analyzer (TGA) after depolymerization). The alumina in the aqueous solution was separated by filtration and dried.

Table 1 shows the time at which the decomposition of the epoxy resin was completed, and the thermal conductivity of the alumina used in the cured epoxy resin of Example 13 and the resultant alumina recovered in Example 13 were measured.

[ Example  14: Chloric acid ( HClO ₃ ) Aqueous solution Filler (silicon carbide)  Decomposition of epoxy resin curing product and separation of filler (silicon carbide)]

The cured product used in Example 14 was an epoxy resin cured product obtained by using a curing agent containing an epoxy compound in the form of a glycidyl ether of cresol novolak and an aromatic amine group as in Example 2, .

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L aqueous chlorine acid solution in an open glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used. On the other hand, in order to provide an aqueous solution of chloric acid to the epoxy resin cured product, a method of bubbling chlorine gas into water and dipping the epoxy resin cured product thereon may be performed.

After 4 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (after the depolymerization, it was confirmed that there was no epoxy resin residue by measurement of the thermogravimetric analyzer (TGA)), the silicon carbide in the aqueous solution was separated by filtration and dried.

The time for completion of the decomposition of the epoxy resin is shown in Table 1 and the results of measurement of the thermal conductivity of the silicon carbide used in the epoxy resin cured product of Example 14 and the resultant silicone carbide recovered in Example 14 are shown in Table 3 .

[ Example  15: Sodium chlorate ( NaClO ₃ ) Aqueous solution Filler (single molecular organic compound Water) and separation of the filler (organic chemical)]

The cured product used in Example 15 was the same as that used in Example 2 except that the epoxy resin cured product obtained by using a curing agent containing an epoxy compound in the form of glycidyl ether of cresol novolak and an aromatic amine group, Compound EFKA 5207 from BASF.

0.1 g of a cured product containing an epoxy resin was added to 70 mL of a 2 mol / L sodium chlorate aqueous solution contained in an opened glass container, followed by stirring at 70 ° C. A pressurized reactor (autoclave) was not used.

After 4.5 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), EFKA 5207 in aqueous solution was measured by 1200 series high performance liquid chromatography And then dried. The time at which the decomposition of the epoxy resin was completed is shown in Table 1.

[ Example  16: An aqueous solution of sodium hydroxide (NaOH) and chlorine Cl ₂ ) Sodium hypochlorite  ( NaOCl ) Aqueous solution, and CFRP  Epoxy resin Hardened  Decomposition and Of filler (carbon fiber)  detach]

0.1 g of the same CFRP as used in Example 1 was added to 70 mL of a 2 mol / L aqueous sodium hydroxide solution in a pressurized vessel, and then, through a separate inlet port, the total pressure of the pressurized vessel was adjusted to 3 atm The mixture was stirred at 70 캜 while the gas was introduced.

After 8 hours, it was confirmed that the epoxy resin was completely depolymerized (it was confirmed that there was no epoxy resin residue through measurement of thermogravimetric analyzer (TGA) after depolymerization), and the carbon fibers in the aqueous solution were separated by filtration and dried. The time at which the decomposition of the epoxy resin was completed is shown in Table 1.

[ Comparative Example  1: a mixture of hydrogen peroxide water and acetone ( H ₂ O ₂  &Lt; + &gt; water + acetone) and separation of carbon fibers]

0.1 g of the same CFRP as used in Example 1 was dissolved in 11 mL of a mixture of 2 mol / L hydrogen peroxide water and 33% (by volume in total solvent) acetone in an open glass vessel (i.e., 33 vol% acetone in the whole solvent, Water volume ratio of 67%), and the mixture was stirred at 70 ° C.

Table 1 shows the decomposition of the epoxy resin. In Comparative Example 1, the epoxy resin did not dissolve and the carbon fiber could not be separated.

Here, OH radicals were used for epoxy decomposition and the dielectric constant of the solution was 44. It is considered that the result is insoluble in this Comparative Example because the dielectric constant is low and radical generation is difficult and OH radical formation is small. It is noted that even though the same CFRP as in the Examples was used (the curing agent of the epoxy resin cured product was hardly decomposed by the aromatic diamine system), unlike the examples, there was no melting at all.

[ Comparative Example  2: Sodium hypochlorite ( NaOCl ) Decomposition of Epoxy Resin and Separation of Carbon Fiber Using Mixed Solution of Aqueous Solution and Acetone]

0.1 g of the same CFRP as used in Example 1 was added to a mixture of an aqueous solution of 2 mol / L sodium hypochlorite and 33% (by volume in total solvent) acetone (that is, 33 vol% acetone in the whole solvent, Water volume ratio of 67%), and then stirred at 70 ° C.

Table 1 shows the decomposition of the epoxy resin. Also in Comparative Example 2, the epoxy resin did not melt and the carbon fiber could not be separated. The dielectric constant of the solution used in this comparative example is about 44. The dielectric constant is low and the radical can not be effectively generated. Therefore, it is considered that the result of this comparative example does not dissolve. It is noted that even though the same CFRP as in the Examples was used (the curing agent of the epoxy resin cured product was hardly decomposed by the aromatic diamine system), unlike the examples, there was no melting at all.

[ Comparative Example  3: Decomposition of epoxy resin using nitric acid aqueous solution and separation of carbon fiber]

0.1 g of the same CFRP as used in Example 1 was added to a 2 mol / L nitric acid aqueous solution contained in an open glass container, followed by stirring at 70 캜.

FIG. 4 is a photograph of a change in nitric acid aqueous solution containing CFRP over time, and FIG. 3 shows a result of measuring pH of an aqueous nitric acid solution containing CFRP. Table 1 shows the time at which decomposition of the epoxy resin was completed, and Table 2 shows the results of measuring the viscosity of the aqueous nitric acid solution obtained by filtering the carbon fibers using a Brookfield viscometer and measuring the pH.

After 12 hours, it was confirmed that the epoxy resin cured product was completely depolymerized (after the depolymerization, the epoxy resin residue was confirmed through the measurement of the thermogravimetric analyzer (TGA)). The carbon fiber in the aqueous solution was separated by filtration and dried.

[ Example  And In comparative examples  Results of epoxy cracking experiments and recovered Filler  Characteristic Analysis]

Table 1 shows the time required for the decomposition of the epoxy resin in Examples and Comparative Examples. Table 2 shows the results of measuring the pH and viscosity of the aqueous sodium hypochlorite solution and the aqueous nitric acid solution obtained by filtering the carbon fibers in Example 1 and Comparative Example 3. [

Table 3 shows the thermal conductivity, tensile strength, and electrical conductivity characteristics before and after depolymerization of the fillers of the examples. Table 4 shows the electrical conductivity results of Example 1 in more detail. Table 5 shows the content of each bond and carbon and oxygen element derived from the X-ray photoelectron spectroscopic analysis results in Example 10.

division XOmYn
compound Reaction solvent / permittivity Time of completion of depolymerization [h] Example 1 NaOCl Aqueous solution (water only)
Dielectric constant 80.2 6 Example 2 HOCl Aqueous solution (water only)
Dielectric constant 80.2 5.5 Example 3 NaOCl Gaseous aqueous solution
(Water only)
Dielectric constant 80.2 8 Example 4 NaOCl Supercritical state
Aqueous solution (water only)
Dielectric constant 80.2 2 Example 5
(CFRP amount
16 times increase) NaOCl Aqueous solution (water only)
Dielectric constant 80.2 12 Example 6
(CFRP amount
10-fold increase / increase in composition amount) NaOCl Aqueous solution (water only)
Dielectric constant 80.2 8 Example 7
(CFRP amount
10-fold increase / increase in composition amount)
(Pulverizing and depolymerization) NaOCl Aqueous solution (water only)
Dielectric constant 80.2 4 Example 8
(CFRP amount
10-fold increase / increase in composition amount)
(Impregnation after impregnation) NaOCl Aqueous solution (water only)
Dielectric constant 80.2 5 Example 9
(CFRP amount
10-fold increase / increase in composition amount)
(Pulverization and impregnation after impregnation) NaOCl Aqueous solution (water only)
Dielectric constant 80.2 3 Example 10 HIO ₃ Aqueous solution (water only)
Dielectric constant 80.2 5 Example 11 HClO ₄ Aqueous solution (water only)
Dielectric constant 80.2 3.5 Example 12 HBrO ₃ Aqueous solution (water only)
Dielectric constant 80.2 4.5 Example 13 HClO ₂ Aqueous solution (water only)
Dielectric constant 80.2 5 Example 14 HClO ₃ Aqueous solution (water only)
Dielectric constant 80.2 4 Example 15 NaClO ₃ Aqueous solution (water only)
Dielectric constant 80.2 4.5 Example 16 NaOH + Cl ₂
(NaOCl production) Aqueous solution (water only)
Dielectric constant 80.2 8 Comparative Example 1 -
(Using hydrogen peroxide) Water + acetone
Permittivity: approx. 44 Does not melt Comparative Example 2 NaOCl Water + acetone
Permittivity: approx. 44 Does not melt Comparative Example 3 -
(Using nitric acid) Aqueous solution
(Water only)
Dielectric constant 80.2 12

division Aqueous sodium hypochlorite solution
(Example 1) Nitric acid aqueous solution
(Comparative Example 3) pH 9 <1 Viscosity [cP] 10 30000

division
(filler) Before / after depolymerization
Thermal conductivity
[W / mK, 25 &lt; 0 &gt; C] Before / after depolymerization
Tensile strength [GPa] Before / after depolymerization
Electrical conductivity [S / cm] Example 1
(Carbon fiber) - 4.0 (Before)
3.7 (after) 504.5 (previous)
657.5 (after) Example 2
(Graphene) 4540 (before)
4041 (after) - - Example 6
(Carbon fiber) - 4.0 (Before)
3.7 (after) 504.5 (previous)
627.5 (after) Example 8
(Carbon fiber) - 4.0 (Before)
3.8 (after) 504.5 (previous)
628.7 (after) Example 11
(Carbon nanotubes) 3111 (Before)
2769 (after) - - Example 12
(glass fiber) - 3.2 (Before)
2.9 (after) - Example 13
(Alumina) 31.2 (Before)
28.4 (after) - - Example 14 (Silicon Carbide) 167 (Before)
157 (after) - -

division Carbon fiber before use
(Example 1) The recovered carbon fiber
(Example 1) Voltage [V] 4.15 4.19 Current [mA] 1.0 1.0 Resistance [kΩ] 4.15 4.19 Length [cm] 1.0 1.0 Thickness [m] 7.8 6.8 Surface area [m ² ] 47.8 36.3 Conductivity [S / cm] 504.5 657.5 Average conductivity 504.5 S / cm 657.5 S / cm

division Pre-use oxidized graphene
(Example 10) The recovered oxidized graphene
(Example 10) C-C content 39.7% 40.5% C-OH content 3.6% 3.7% C-O-C content 41.3% 40.2% C = O content 12.5% 13.7% C (= O) -O content 2.9% 1.9% Carbon element content 66.5% 65.7% Oxygen element content 33.5% 34.3%

As can be seen from the examples and comparative examples in Table 1, the reaction time was relatively fast and the reaction time was relatively fast in the Examples. On the other hand, in Comparative Examples 1 and 2, it was confirmed that decomposition of the epoxy resin cured product was not progressed when about 33% by volume of acetone was contained in the reaction solvent (dielectric constant was about 44).

On the other hand, in the case of Comparative Example 3, a nitric acid aqueous solution was used, but the reaction time was twice as slow as that of Example 1 in which an aqueous solution of sodium hypochlorite was used. As shown in Table 2, the composition used in Example 1 exhibited a pH value higher than that of the nitric acid aqueous solution, and the resulting mixed solution after decomposing the cured epoxy resin showed a viscosity higher than that of nitric acid, . Since the viscosity is relatively low, the process can be performed more easily.

5 is a graph comparing the results obtained by measuring the tensile strengths of the carbon fibers (raw material carbon fibers) used in the CFRP of Example 1 of the present invention and the carbon fibers obtained as a result of Example 1. Fig.

From the results of measurement of the tensile strength of the carbon fibers recovered from Example 1, the decomposition of CFRP using the methods of the embodiments of the present invention enables the recovery of carbon fibers having a small decrease in tensile strength (within about 13%) from CFRP Respectively. This is because when carbon fibers recovered from CFRP by pyrolysis show a decrease in tensile strength of not less than 15% of the raw material (Non-Patent Document 1), the depolymerization method according to the embodiments of the present invention has high- Can be recovered.

Further, as shown in Table 3, it was confirmed from the results of the filler characteristics before and after depolymerization that the epoxy resin cured product was decomposed using the method of the embodiments of the present invention, whereby the filler with little change in properties could be recovered from the epoxy resin cured product .

In Examples 7 to 9 and 6 of Table 1, the same epoxy resin cured product and a depolymerized composition were used, respectively. Examples 7 to 9 proceeded with a pretreatment step, whereas Example 6 was a pretreatment step . Despite the rapid depolymerization in Example 6 as well, the epoxy resin cured product disintegrated in a shorter time by including the pretreatment step, and the depolymerization of the epoxy resin cured product in the earliest time in Example 9 including both the pulverization and the impregnation process Was completed.

The reason for the shortening of the depolymerization completion time is that the depolymerization is further activated by the increase of the depolymerization reaction area of the epoxy resin cured product due to the pretreatment. Activation of this depolymerization occurs not only by increasing the reaction area using physical methods such as pulverization but also by increasing the reaction area through a chemical method such as an impregnation method.

As shown in Table 3, the tensile strength and electrical conductivity of the carbon fibers recovered as a result of Example 8 including the impregnation process were higher than the tensile strength and electrical conductivity of the carbon fibers recovered as the result of Example 6, Respectively. This indicates that the degradation of the carbon fiber properties that can occur during the depolymerization process is further reduced because the time taken for depolymerization of the epoxy resin cured product through the pretreatment process is reduced.

The results obtained by measuring the electrical conductivities of the carbon fibers used in the CFRP of Example 1 of the present invention and the carbon fibers obtained as a result of Example 1 are shown in Table 4 in detail. As can be seen from Table 4, it was confirmed that by decomposing CFRP using the method of the embodiments of the present invention, carbon fibers having an electric conductivity improved by 30% can be recovered from CFRP. From the measurement of tensile strength and the result of electrical conductivity, it was confirmed that carbon fibers having excellent physical properties can be recovered from CFRP by decomposing CFRP using the methods of the embodiments of the present invention.

[Experiment 2]

As a semi-solvent, NMP  Mixed solvent use

In Experiment 2, the mixing ratio of water and NMP was used as a reaction solvent, and the permittivity was changed and the degree of epoxy depolymerization was measured. The compound was, for example, sodium hypochlorite. Table 6 shows experimental conditions and results.

CFRP
weight Acetic acid
Pretreatment condition NaOCl
Depolymerization reaction
Condition Water: NMP Mixed solvent
permittivity Depolarization
Before reaction
Epoxy
content
(%) Depolarization
After the reaction
Epoxy
content*
(%) Decomposition rate (%) * 0.1 g 120 &lt;
30 minutes 3 M,
70 ml,
90 ° C
0: 100 43 19.4 19.4
(After 24 hours) 0
(After 24 hours) 30:70 51.7 19.4 17.4
(After 24 hours) 10.3
(After 24 hours) 50:50 59.4 19.4 17.3
(After 24 hours) 10.8
(After 24 hours) 60:40 63.8 19.4 17.1
(After 24 hours) 11.8
(After 24 hours) 70:30 68.3 19.4 11.9
(After 24 hours) 38.6
(After 24 hours) 80:20 73.9 19.4 9
(After 24 hours) 53.6
(After 24 hours) 90:10 78.1 19.4 4.7
(After 24 hours) 75.8
(After 24 hours) 100: 0 80.2 19.4 0.0
(After 5 hours) 100
(After 5 hours)

* The content of epoxy resin (cured epoxy resin) before the depolymerization reaction of CFRP was 19.4%. The epoxy resin content was measured after the depolymerization reaction for 24 hours or 5 hours (in the case of 100% water, the residual amount of epoxy resin already showed a remarkable difference of 0% after 5 hours).

Decomposition rate (depolarization efficiency) was calculated as follows.

Decomposition ratio = [(epoxy resin content before depolymerization reaction of CFRP-epoxy resin content after depolymerization reaction of CFRP) / epoxy resin content before depolymerization reaction of CFRP] X 100

As a reaction solvent, DMF  Mixed solvent use

The permittivity was changed by using a mixed solvent of water and DMF as a reaction solvent, and the degree of depolymerization was measured. The compound was sodium hypochlorite. Table 7 shows the experimental conditions and results.

CFRP
weight Acetic acid
Pretreatment condition NaOCl
Depolymerization reaction
Condition Water: DMF Mixed solvent
permittivity Depolarization
Before reaction
Epoxy
content
(%) Depolarization
After the reaction
Epoxy
content*
(%) Decomposition rate (%) * 0.1 g



120 &lt;
30 minutes



3 M,
70 ml,
90 ° C




0: 100 46.7 19.4 18.8
(After 24 hours) 3
(After 24 hours) 40:60 65.2 19.4 17.3
(After 24 hours) 11
(After 24 hours) 60:40 70.2 19.4 11.6
(After 24 hours) 40
(After 24 hours) 67:33 72.2 19.4 8.7
(After 24 hours) 55
(After 24 hours) 87:13 77.2 19.4 7.0
(After 24 hours) 64
(After 24 hours)

* The content of epoxy resin (cured epoxy resin) before the depolymerization reaction of CFRP was 19.4%. After the 24 hour depolymerization reaction, the epoxy resin content was measured.

* Decomposition rate (depolarization efficiency) was calculated as follows.

Decomposition ratio = [(epoxy resin content before depolymerization reaction of CFRP-epoxy resin content after depolymerization reaction of CFRP) / epoxy resin content before depolymerization reaction of CFRP] X 100

Use of mixed solvent of water and acetone as reaction solvent

As a reaction solvent, the mixing ratio of water and acetone was used to change the permittivity and the epoxy depolymerization degree was measured. The compound was sodium hypochlorite. Table 8 shows the experimental conditions and results.

CFRP
weight Acetic acid
Pretreatment condition NaOCl
Depolymerization reaction
Condition Water: acetone Mixed solvent
permittivity Depolarization
Before reaction
Epoxy
content
(%) Depolarization
After the reaction
Epoxy
content*
(%) Decomposition rate (%) * 0.1 g



120 &lt;
30 minutes



3 M,
70 ml,
90 ° C




0: 100 40.3 19.4 19.4
(After 24 hours) 0
(After 24 hours) 35:65 42.9 19.4 17.5
(After 24 hours) 10
(After 24 hours) 65:35 62.5 19.4 16.7
(After 24 hours) 14
(After 24 hours) 75:25 68.6 19.4 13.4
(After 24 hours) 34
(After 24 hours) 88:12 74.8 19.4 9
(After 24 hours) 45
(After 24 hours)

* The content of epoxy resin (cured epoxy resin) before the depolymerization reaction of CFRP was 19.4%. After the 24 hour depolymerization reaction, the epoxy resin content was measured.

* Decomposition rate (depolarization efficiency) was calculated as follows.

Decomposition ratio = [(epoxy resin content before depolymerization reaction of CFRP-epoxy resin content after depolymerization reaction of CFRP) / epoxy resin content before depolymerization reaction of CFRP] X 100

9 is a graph showing the depolymerization ratio of the epoxy resin cured product according to the dielectric constant in the case of each mixed solvent in the exemplary embodiment of the present invention.

As can be seen from this, it can be seen that the slope of the depolymerization efficiency is drastically increased when the permittivity is about 65 or more. In particular, as shown in the WATER / NMP data, in the case of water alone, a decomposition ratio of 100 is attained within 5 hours instead of 24 hours. As compared with the case of mixing with an organic solvent, the decomposition rate is remarkably increased .

[Experiment 3]

In Experiment 3, it was experimentally determined whether depolymerization reaction of the epoxy resin cured product was accelerated by addition of a radical additive.

Example 1 of this Experiment 3 and Comparative Example are as follows.

[Example 1: Decomposition of Cured Epoxy Resin in CFRP and Separation of Carbon Fiber Using Sodium Hypochlorite (NaOCl) Aqueous Solution and Sodium Percarbonate]

The epoxy resin cured product used in Example 1 of Experiment 3 is a closed CFRP. The waste CFRP is composed of an epoxy resin cured product of a diglycidyl ether type of bisphenol A and a curing agent containing an aliphatic amine group and a carbon fiber.

10.7 g of the above-mentioned CFRP and 1 g of sodium percarbonate (2Na ₂ CO ₃ 3H ₂ O ₂ ) were added to 2.5 L of a 0.4 mol / L sodium hypochlorite aqueous solution contained in a pressurized reactor, and the mixture was stirred at 150 ° C. After 3 hours, the carbon fibers in the aqueous solution were separated and dried.

The results of the thermogravimetric analysis of the recovered carbon fibers are shown in Fig. From the weight change at 300 to 400 degrees shown in the thermogravimetric analysis, the decomposition rate of the epoxy resin cured product was calculated using the following equation, and the results are shown in Table 9.

[Comparative Example 1: Decomposition of Cured Epoxy Resin in CFRP and Separation of Carbon Fiber Using Sodium Hypochlorite (NaOCl) Aqueous Solution]

10.7 g of the same pulped CFRP as used in Example 1 was used, but unlike Example 1, sodium percarbonate (2Na ₂ CO ₃ 3H ₂ O ₂ ) was not used. Was added to 2.5 L of a 0.4 mol / L sodium hypochlorite aqueous solution contained in the pressurized reactor, and the mixture was stirred at 150 ° C. After 3 hours, the carbon fibers in the aqueous solution were separated and dried.

The results of thermogravimetric analysis of the recovered carbon fibers are shown in Fig. The degradation rate of the epoxy resin cured product was calculated from the weight change amount at 300 to 400 degrees shown in the thermogravimetric analysis results using the same formula as in Example 1. The results are shown in Table 9. [

Example 1 Comparative Example 1 Epoxy content in CFRP 20% 20% Epoxy residue after depolymerization 10% 17% Decomposition rate 50% 15%

10 is a graph showing the results of depolymerization of Example 1 when the radical-providing additive is added in Experiment 3 of the present invention, and Fig. 11 is a graph showing the results of depolymerization of Comparative Example 1 when the radical- Fig.

As can be seen from the results of FIGS. 10 and 11 and Table 9, when the radical addition additive sodium percarbonate was added together, the polymerization efficiency was about 35% higher at the same time, indicating that the depolymerization reaction was promoted by the radical additive have. This can greatly shorten the time and cost involved in the depolymerization process of the epoxy resin cured product.

As can be seen from the above, it can be seen that the reaction solvent in the depolymerization composition according to the embodiments of the present invention is particularly preferably water alone. When water is included but other solvents are mixed, a sharp increase in the decomposition rate occurs when the permittivity of the mixed solvent is at least about 65 or more. Then, in the case of water alone, the reaction time itself was remarkably decreased and the reaction efficiency was remarkably increased.

Claims (34)

An epoxy resin cured product,
A compound represented by the formula XOmYn wherein X is hydrogen or an alkali metal or an alkaline earth metal, Y is halogen, m satisfies 1? M? 8, and n satisfies 1? N? 6; And a reaction solvent,
Wherein X is dissociated from XOmYn in the reaction solvent and a Y radical can be provided.
The method according to claim 1,
Wherein the reaction solvent has a dielectric constant of 65 or more, 70 or more, 75 or more, or 80 or more.
The method according to claim 1,
The reaction solvent includes H ₂ O, and a dielectric constant of 65 or more or 70 or more or 75 or more or 80 or more H ₂ O based on the reaction solvent in the polymerization by the epoxy resin cured composition that is characterized by.
The method of claim 3,
H ₂ O is a liquid, gaseous or supercritical state.
The method of claim 3,
Wherein the reaction solvent is water alone.
6. The method of claim 5,
Wherein the composition exhibits a pH of 1 to 14 or 8 to 14 when X is an alkali metal or an alkaline earth metal.
The method according to claim 1,
The compounds HOF, HOCl, HOBr, HOI, NaOF, NaOCl, NaOBr, NaOI, LiOF, LiOCl, LiOBr, LiOI, KOF, KOCl, KOBr, KOI, HO 2 F, HO 2 Cl, HO 2 Br, HO 2 I , Na ₂ F, NaO ₂ Cl, NaO ₂ Br, NaO ₂ I, LiO ₂ F, LiO ₂ Cl, LiO ₂ Br, LiO ₂ I, KO ₂ F, KO ₂ Cl, KO ₂ Br, KO ₂ I, Ca (OF) ₂ , Ca (OCl) ₂ , Ca (OBr) ₂ , Ca (OI) ₂ , HO ₃ F, HO ₃ Cl, HO ₃ Br, HO ₃ I, NaO ₃ F, NaO ₃ Cl, NaO ₃ Br , Na ₃ I, LiO ₃ F, LiO ₃ Cl, LiO ₃ Br, LiO ₃ I, KO ₃ F, KO ₃ Cl, KO ₃ Br, KO ₃ I, HO ₄ F, HO ₄ Cl, HO ₄ Br, HO _{4 I, NaO 4 F, NaO} 4 Cl, NaO 4 Br, NaO 4 I, LiO 4 F, LiO 4 Cl, LiO 4 Br, LiO 4 I, KO 4 F, KO 4 Cl, KO 4 Br, KO 4 I _{, NaOCl 6, MgO 6 F 2} , MgO 6 Cl 2, MgO 6 Br 2, MgO 6 I 2, CaO 6 F 2, CaO 6 Cl 2, CaO 6 Br 2, CaO 6 I 2, SrO 6 F 2, SrO _{6 Cl 2, SrO 6 Br 2} , SrO 6 I 2, BaO 6 F 2, BaO 6 Cl 2, BaO 6 Br 2, BaO 6 I 2, NaOCl 3, NaOCl 4, MgO 8 Cl 2, CaO 8 Cl 2, SrO ₈ Cl ₂ , and BaO ₈ Cl ₂ . Composition.
The method according to claim 1,
Wherein the compound is contained in an amount of 0.001 to 99% by weight based on the depolymerization composition.
The method according to claim 1,
Wherein the depolymerization composition further comprises a radical-providing additive capable of promoting the radical generation reaction of XomYn.
10. The method of claim 9,
Wherein the radical-providing additive is at least one selected from radical-containing compounds or radical-generating compounds in the reaction system.
10. The method of claim 9,
Wherein the radical-providing additive is contained in an amount of 0.00001 to 99% by weight based on 100% by weight of the entire composition.
As the depolymerization product of the epoxy resin cured product,
Wherein the product comprises CY (Y is a halogen) bond bonded to Y on carbon.
13. The method of claim 12,
The epoxy resin cured product of the depolymerization product further comprises at least one selected from a filler and a polymer resin.
As a filler obtained by depolymerizing an epoxy resin cured product containing a filler,
A filler obtained by depolymerizing an epoxy resin cured product with the depolymerization composition according to any one of claims 1 to 11.
15. The method of claim 14,
The filler is selected from the group consisting of carbon fiber, graphite, graphene, oxide graphene, reduced graphene, carbon nanotubes, glass fiber, inorganic salt, metal particles, ceramic, monomolecular organic compound, monomolecular silicon compound, Wherein the filler is at least one of the fillers.
As an epoxy resin curing solution polymerization method,
The epoxy resin cured product is depolymerized using the epoxy resin cured product,
Wherein the epoxy resin depolymerization composition comprises a compound represented by the formula XOmYn wherein X is hydrogen or an alkali metal or an alkaline earth metal and Y is halogen and m satisfies 1? M? 8 and n satisfies 1? N? 6. &Lt; / RTI &gt; And a reaction solvent; , Wherein X in the reaction solvent can be dissociated from XOmYn and a Y radical can be provided.
17. The method of claim 16,
Wherein the reaction solvent has a dielectric constant of 65 or more, 70 or more, 75 or more, or 80 or more.
17. The method of claim 16,
The reaction solvent, including H ₂ O, and a dielectric constant of an epoxy resin cured product, characterized in that H ₂ O based on the reaction solvent or more than 65 or more than 70 or 75 or 80 or more polymerization processes.
17. The method of claim 16,
Wherein the depolymerization composition is an aqueous solution containing the compound.
17. The method of claim 16,
Wherein the depolymerization reaction temperature is 20 to 200 ° C or 20 to 100 ° C.
17. The method of claim 16,
Wherein the epoxy resin cured product is used in an amount of 1 to 90 parts by weight based on 100 parts by weight of the depolymerization composition.
17. The method of claim 16,
Wherein the depolymerization process is repeated by adding a new epoxy resin cured product to the remaining reaction solvent after depolymerization of the cured product of the epoxy resin.
17. The method of claim 16,
Wherein the method comprises pretreating the epoxy resin cured product to increase the reaction surface area of the epoxy resin cured product before providing the cured product of the epoxy resin to the polymerization reaction.
24. The method of claim 23,
Wherein the pre-treatment is one of physical pretreatment and chemical pretreatment, or a combination thereof.
25. The method of claim 24,
Wherein the physical pretreatment is at least one selected from dry grinding and wet grinding.
25. The method of claim 24,
Wherein the chemical pretreatment comprises impregnating the acidic composition with a cured epoxy resin.
17. The method of claim 16,
&Lt; RTI ID = 0.0 &gt; XOmYn &lt; / RTI &gt; compound.
28. The method of claim 27,
Wherein the XOmYn compound is HOY (Y is halogen) and bubbling Y gas into water to make an aqueous solution containing the HOY compound.
28. The method of claim 27,
Wherein the XOmYn compound is XOY wherein X is an alkali metal and Y is a halogen and electrolyzing XY with water to produce an aqueous solution containing the XOY compound.
28. The method of claim 27,
Characterized in that an XOmYn compound is chemically or physically produced in a depolymerization reactor of an epoxy resin cured product and depolymerization of the epoxy resin cured product is carried out.
31. The method of claim 30,
The XOmYn compound is sodium hypochlorite (NaOCl)
Characterized in that sodium hypochlorite (NaOCl) is produced from a mixture of sodium hydroxide (NaOH) and chlorine (Cl ₂ ) in a depolymerization reactor of an epoxy resin cured product to perform depolymerization of the epoxy resin cured product .
17. The method of claim 16,
Wherein the depolymerization composition further comprises a radical-providing additive capable of promoting the radical generation reaction of XOmYn.
33. The method of claim 32,
Wherein the radical-providing additive is at least one selected from a radical-containing compound or a radical-generating compound in the reaction system.
A method for separating a filler from an epoxy resin cured product,
Depolymerizing the epoxy resin cured product using the epoxy resin cured product; And
And obtaining a filler from the depolymerized epoxy resin cured product,
Wherein the epoxy resin depolymerization composition comprises a compound represented by the formula XOmYn wherein X is hydrogen or an alkali metal or an alkaline earth metal and Y is halogen and m satisfies 1? M? 8 and n satisfies 1? N? 6. &Lt; / RTI &gt; And a reaction solvent; Characterized in that in the reaction solvent X is cleaved from XOmYn and a Y radical can be provided.

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