KR102766544B1 - Removal of PET and PVC recycling methods for recycling waste tarpaulin - Google Patents

Abstract

The present invention relates to a method for recycling PVC tarpaulin containing polyethylene terephthalate (PET) fibers.
In the present invention, PET fibers woven into PVC tarpaulin are decomposed into BHET compounds through a glycol decomposition reaction, and the decomposed BHET compounds exist in a state dissolved in glycol. After the glycol decomposition reaction, a solid containing a PVC composition is recovered through a separation process of the decomposed product, and further, the BHET compounds, which are decomposed products, can be separated by applying cooling precipitation to the glycol compound in which the BHET compounds are dissolved.

Description

{Removal of PET and PVC recycling methods for recycling waste tarpaulin}

The present invention relates to a method for effectively recycling PVC tarpaulin containing PET fibers by separating PET from PVC tarpaulin and recycling tarpaulin decomposition products having a PVC composition and PET composition, respectively.

In addition, the present invention relates to a method for recycling PVC tarpaulin, in which PET fibers are chemically degraded into BHET types to separate them from the PVC composition, and the tarpaulin decomposition products and BHET types are recovered to recycle the PVC composition and PET composition of the PVC tarpaulin, respectively.

In addition, the present invention relates to a method for manufacturing a new recycled PVC sheet by adding recovered tarpaulin decomposition material at a certain content ratio.

Plastics are currently used for a variety of purposes, including construction, agriculture, advertising, and even daily necessities, and their use is increasing. As plastic use increases, interest in plastic waste management is also increasing, and some countries have legally mandated recycling, banning the use of plastics that cannot be recycled. In this way, recycling plastics is desirable in terms of environmental protection, and can also meet the demands of a society that pursues sustainability.

Currently, polyvinyl chloride (PVC) is used for a variety of purposes, including industrial materials for construction, agriculture, advertising, and daily necessities.

In particular, the PVC tarpaulin, which is the raw material of the present invention, is a composite plastic structure in which PET fabric as a skeleton is coated with PVC fabric. PVC tarpaulin has excellent physical properties such as high tensile strength, flexibility, and waterproofness, and thus has many uses in various fields such as tents, advertising banners, and agricultural containers, and is consumed worldwide. However, most of the waste PVC tarpaulin is incinerated or landfilled. This is because it is difficult to process because it exists mixed with woven PET fibers in addition to PVC, and the PET fibers remaining after processing cause surface defects and a decrease in physical properties, which lowers the value of the product. However, in the case of incineration of polyvinyl chloride as described above, toxic chlorine gas is generated due to the decomposition of the polyvinyl chloride itself, which causes an environmental pollution problem.

On the other hand, each component that makes up PVC tarpaulin has a single plastic recycling method reported. PET, one of the main components of tarpaulin, is a polyester in which the monomers terephthalic acid (TPA) and ethylene glycol (EG) are cross-polymerized through ester bonds. PET is being recycled chemically by depolymerizing the polymer into monomers and materials. The depolymerization reaction varies depending on the solvent used, and is divided into hydrolysis when water is used, aminolysis when amines are used, alcohololysis when alcohols are used, and glycolysis when glycols are used. Among them, glycolysis has the advantages of low initial investment costs, a simple process, and easy application to existing PET production plants. When EG is used as a solvent in glycol decomposition, BHET is produced as a monomer, and BHET is dissolved in EG and exists in the liquid fraction of the reactant. BHET present in the reactant can be recovered and reused in PET production, etc.

The remaining main component of tarpaulin, PVC, is hydrophobic and therefore does not dissolve in EG and exists in the solid fraction of the reactant. Generally, waste PVC can be recycled through a process of crushing, washing, and then melting and molding again. Therefore, a mechanical recycling method of crushing PVC tarpaulin, physically removing PET fibers, and adding them at a certain content ratio to manufacture PVC sheets has been performed. However, the problem with the above technology is that the PET fibers are not completely removed from the PVC tarpaulin by the crushing and physical separation processes. Since the PET fibers that are not completely removed exist in the recycled sheet, the fibers protrude on the surface of the recycled sheet made by the above technology and the physical properties decrease due to the residual PET fibers inside the sheet, so that it has been utilized in limited areas.

Therefore, in order to recycle PVC tarpaulin, it is necessary to separate PET fibers woven into waste PVC tarpaulin. In order to solve the above problems, the present invention performed a glycol decomposition process to separate the PVC composition and PET composition mixed in PVC tarpaulin waste. The present invention proposes a method of separating the PET composition from the tarpaulin decomposition product after reducing the molecular weight of the PET composition through the glycol decomposition process, and recovering and recycling the tarpaulin decomposition product and BHET, respectively.

The recycling of general waste PVC tarpaulins was conducted by mechanically crushing the PET fibers and PVC sheets woven into the PVC tarpaulin together to reduce the size of the PET fibers, thereby suppressing the protrusion of the fibers in the appearance that occurs during the reprocessing process and the change in the physical properties caused by the fibers. In particular, the appearance defects that may occur due to the fibers were suppressed by mixing the crushed material with plasticized PVC to induce the fibers to be uniformly dispersed in the mixture. However, since the technology does not essentially remove the PET fibers, the mechanical properties of the product manufactured as a result of recycling were changed, and this limited the use of recycling.

The present invention provides a method for separating a PVC sheet and PET fiber by performing a glycol decomposition reaction on a PVC tarpaulin containing PET fiber with a glycol compound to reduce the molecular weight to a BHET type.

The tarpaulin decomposition product recovered through the above method can be added to the PVC sheet synthesis process at a certain ratio to manufacture a recycled sheet, and the BHET type can be recycled as a raw material for unsaturated polyester resin and polyol through an additional process. Therefore, the purpose of the present invention is to provide a recycling method that can dramatically increase the regeneration efficiency of waste PVC tarpaulin and minimize waste by recycling PVC sheets and PET fibers, respectively.

The present invention comprises a step (step a) of subjecting a mixture comprising PVC tarpaulin pulverized material, a glycol compound and a catalyst to a glycol decomposition reaction to decompose PET fibers present in the PVC tarpaulin pulverized material into bis-2-hydroxyethyl terephthalates (BHETs);

A step (step b) of filtering the reaction product of step a to separate the solid residue containing the tarpaulin decomposition product and the filtrate;

A step (step c) of washing and drying the tarpaulin decomposition product separated in the above step b; and

A method for recycling PVC tarpaulin containing PET fibers is provided, comprising recovering BHET compounds from the filtrate separated in step b and regenerating a glycol compound as a solvent (step d).

In addition, the present invention relates to PVC;

Tarpaulin decomposition product manufactured by the recycling method of PVC tarpaulin containing the aforementioned PET fiber; and

It is manufactured by the step of molding a waste resin composition containing an additive,

A recycled PVC sheet is provided, wherein the content of the above tarpaulin decomposition product is 5 to 100 parts by weight based on 100 parts by weight of PVC.

In the present invention, PET fibers can be efficiently separated and removed in the form of BHET from PVC tarpaulin containing PET fibers, thereby dramatically improving the regeneration efficiency of PVC tarpaulin.

In the present invention, PET fibers woven into PVC tarpaulin are separated from the PVC sheet in the form of BHETs, so that the PET and PVC can be recycled respectively. BHETs, which are decomposition products of PET fibers, can be used as raw materials for unsaturated polyester resins and polyols, and a solid content containing a tarpaulin decomposition product having a PVC composition can be added at a certain content ratio to the production of PVC sheets, thereby suppressing the protrusion of PET fibers on the surface of the sheet, thereby producing a recycled PVC sheet having excellent mechanical properties and a well-controlled surface condition. In addition, the solvent from which BHETs have been removed can be reused when performing a new glycol decomposition reaction, so that the PVC tarpaulin can be recycled economically. As a result, it is possible to escape from the conventional PVC tarpaulin recycling method that relied on complete incineration or landfill, thereby meeting the demand for environmental conservation and dramatically improving the regeneration efficiency of PVC tarpaulin waste.

In the present invention, BHET, which is a PET fiber decomposition product generated in the first reactor, which is a glycolysis reactor, exists in a dissolved state in EG, which is a liquid fraction, and therefore can be separated from the waste PVC tarpaulin, which is a solid fraction, through filtration. The BHET present in the filtrate can be purified through an additional recovery process and used as a raw material for polymer synthesis, and therefore is the same as the PET recycling flow according to the chemical recycling method. Since the PVC tarpaulin from which the PET fibers have been removed has a PVC composition, a recycled sheet can be manufactured by adding it at a certain content ratio. This meets the demand for environmental conservation issues. In addition, by removing the PET fibers from the waste PVC tarpaulin, the fiber structure does not protrude to the outside, so the surface condition is good, and the product can be recycled as a product with equivalent mechanical properties. The sheet can be used as a sheet product such as a flooring material, a waterproofing sheet, and an interlayer barrier material of a building.

In addition, since the solvent used in the glycol decomposition reaction can be reused even without completely recovering the BHET, it is possible to save more time and energy and secure economic feasibility. Accordingly, the present invention can provide an efficient recycling method of waste PVC tarpaulin containing PET fibers.

Figures 1 and 2 are process schematics for a method of recycling waste PVC tarpaulin.
Figure 3 shows photographs before and after crushing waste PVC tarpaulin.
Figure 4 shows the results of measuring the PET degradation rate of a tarpaulin degradation product sample using a betaine catalyst.
Figure 5 shows the definition of PET degradation rate.
Figure 6 shows the results of tracking the PET degradation rate of a tarpaulin degradation product sample over time using a zinc acetate catalyst.
Figure 7 shows a photograph of PET fibers observed on the surface during the roll mill process during the process of manufacturing recycled PVC sheets.
Figure 8 shows an enlarged photograph of the surface of a recycled PVC sheet specimen.
Figure 9 shows the results of evaluating the mechanical properties of recycled PVC sheet specimens.
Figures 10 and 11 show enlarged photographs of the surface of a recycled PVC sheet specimen.
Figures 12 and 13 show the results of evaluating the mechanical properties of recycled PVC sheet specimens.

The present invention relates to a method for recycling PVC tarpaulin containing PET fibers, the recycling method comprising the steps of: (step a) subjecting a mixture containing PVC tarpaulin pulverized material, a glycol compound and a catalyst to a glycolysis reaction to decompose PET fibers present in the PVC tarpaulin pulverized material into bis-2-hydroxyethyl terephthalates (BHETs);

A step (step b) of filtering the reaction product of step a to separate the solid residue containing the tarpaulin decomposition product and the filtrate;

A step (step c) of washing and drying the tarpaulin decomposition product separated in the above step b; and

It includes a step (step d) of recovering BHET from the filtrate separated in the above step b and regenerating a glycol compound as a solvent.

In the present invention, a glycol decomposition reaction is performed on waste PVC tarpaulin to decompose residual PET fibers into BHETs. Afterwards, a filtration process is performed to obtain solid residues and a filtrate (a mixture of BHETs and a solvent), and the solid residues are recovered through a washing and drying process. The recovered filtrate undergoes a separation process to separate and recover BHETs and a solvent.

Hereinafter, a method for recycling PVC tarpaulin containing PET fiber of the present invention will be specifically described.

Step a

Step a is a glycol decomposition step, in which a mixture including PVC tarpaulin pulverized material, a glycol compound, and a catalyst is subjected to a glycol decomposition reaction to decompose PET fibers present in the PVC tarpaulin pulverized material into bis-2-hydroxyethyl terephthalates (BHETs).

In one specific example, the PVC tarpaulin includes PET fibers. Specifically, the PVC tarpaulin is a composite plastic structure in which PET fibers as a skeleton are coated with PVC sheets. The PVC sheet may include PVC, a filler, a plasticizer, an activator, and the like, and a composition including the PVC, the filler, the plasticizer, and the activator may be referred to as a PVC composition. The content of the PET fibers in the PVC tarpaulin may be 0 to 30 wt%, 1 to 30 wt%, or 10 to 20 wt%.

In one specific example, the PVC tarpaulin may be waste PVC tarpaulin.

In one specific example, the PVC tarpaulin shredder may be obtained by mechanically shredding the PVC tarpaulin. The size of the PVC tarpaulin shredder may be 3 mm or less or 0.1 to 3 mm. Through the shredding, the PET fiber tissue within the PVC tarpaulin may be shredded while mechanically separating the PVC fabric and the PET fiber to a certain extent.

In one specific example, the type of glycol compound is not limited as long as it can glycolyze PET, and for example, at least one selected from the group consisting of ethylene glycol (EG, hereinafter EG), 1,3-propanediol (PDO), and 1,4-butanediol (BDO) can be used.

In one specific example, the weight ratio of the PVC tarpaulin shredded material and the glycol compound may be 1:4 to 1:100. The weight ratio is equivalent to adding 25 to 500 times the excess of the compound compared to the PET composition in the PVC tarpaulin waste at normal pressure stoichiometrically.

In one specific example, the catalyst may be at least one selected from the group consisting of betaine, zinc acetate, and lead acetate. The content of the catalyst may be 0.065 to 3 parts by weight.

In the present invention, step a may be performed in a reactor, and the reactor may be referred to as a first reactor.

In one specific embodiment, the first reactor may be equipped with a stirrer, a condenser, a temperature sensor, and the like.

In step a of the present invention, the first reactor is heated to 190°C over a period of about 30 minutes, and when the first reactor reaches 190°C, a glycol decomposition reaction can be performed at a temperature of 185°C to 196°C for 10 minutes to 4 hours or 1 to 2 hours.

Accordingly, in the first reactor, PET fibers present in the PVC tarpaulin pulverized material can be decomposed to produce bis-2-hydroxyethyl terephthalates (BHETs), etc.

In one specific embodiment, the degradation rate of PET fibers in PVC tarpaulin can be 50 to 100% or 60 to 100%.

In one specific embodiment, the reactants of step a can comprise 0.15 to 0.4 wt % of BHET compounds, 0.75 to 2.5 wt % of solid residue and unreacted glycol compounds.

In one specific embodiment, the BHETs may include one or more selected from the group consisting of bis-2-hydroxyethyl terephthalate (BHET), bis-3-hydroxypropyl terephthalate (BHPT), bis-4-hydroxybutyl terephthalate (BHBT), and oligomers of the aforementioned monomers.

In one specific example, the solid residue may include tarpaulin decomposition products (PVC composition), foreign substances, and non-decomposed PET fibers. The tarpaulin decomposition products may include a composite of PVC, fillers, plasticizers, and activators used in sheet manufacturing, as a composition constituting a PVC sheet. Since the solid residue exists in a solid state, it can be separated through a solid-liquid separation step described below.

step b

Step b is a solid-liquid separation step, which is a step of filtering the reactant of step a to separate the solid residue containing the tarpaulin decomposition product and the filtrate. In step b, the tarpaulin decomposition product can be first separated from the reactant.

In one specific embodiment, step b can be performed in a filter.

In one specific embodiment, step b may be performed at a temperature of about 80° C. to minimize separation process inhibition due to the viscosity of the glycol compound.

In one specific example, the solid-liquid separation process is not limited to a method capable of separating a solid from a reaction solution, and may use a gravity separation method or a centrifugal separation method, etc. Specifically, a solid residue, which is a solid component of the reaction product, can be separated using a 0.125 mm filter.

In one specific embodiment, the reactants can be separated into a solid residue and a filtrate.

The above solid residue may include tarpaulin decomposition products, foreign substances, and non-decomposed PET fibers constituting the PVC sheet. The above tarpaulin decomposition products include PVC, fillers, plasticizers, and lubricants, and since they do not participate in the glycol decomposition reaction, the solid content can be separated through filtration without a separate process.

The above filtrate contains a mixture of BHET and unreacted glycol compounds. The BHET contained in the filtrate can be recovered by crystallizing through cooling and then precipitating in the BHET recovery process described later. The unreacted glycol compound can be sent to the first reactor after recovery and reused.

In one specific embodiment, the solid residue can be recovered and conveyed to a blender for manufacturing PVC sheet. Additionally, the filtrate can be conveyed to a second reactor for further separation processes.

The amount of filtrate transferred to the second reactor in step b may be 80 to 95 wt% of the total weight of the reactants in step a.

step c

Step c is a step for recovering tarpaulin decomposition products (PVC composition), which is a step for washing and drying the solid residue separated in step b.

The solid residue recovered in step b described above may include tarpaulin decomposition products, foreign substances, and non-decomposed PET fibers. The tarpaulin decomposition products may include PVC, fillers, plasticizers, and lubricants used in the manufacture of the sheet, as a composition constituting the PVC sheet.

In step c, the solid residue can be conveyed to a washer.

In one specific embodiment, washing can continue until greater than 95% of the glycol compounds in the solid residue are removed.

In one specific example, the washing may be performed using a washing solution at 40°C, a temperature at which more than 95% of the glycol compound can be washed away without causing deformation of the tarpaulin decomposition product.

In step c, drying can be performed at a temperature of 95°C to 105°C for 6 to 12 hours, or the washed sample can be frozen at -20°C and then freeze-dried at a temperature of -40°C or lower under negative pressure for 24 hours or more. The higher the drying temperature, the shorter the drying time, but there is a possibility that the tarpaulin decomposition product will deform. In addition, the lower the temperature, the longer the drying time, but the more the tarpaulin decomposition product can be prevented from deforming. Therefore, drying can be performed at an appropriate drying temperature that can avoid deforming the tarpaulin decomposition product.

step d

Step d is a BHET separation step, which recovers BHET from the filtrate separated in step b and regenerates the glycol compound, which is a solvent.

In one specific embodiment, the filtrate separated in step b can comprise 0.15 to 4 wt % of BHET compounds and unreacted glycol compounds.

The above filtrate is transferred to a second reactor and can remove fine foreign substances, etc. through a filtering process.

In one specific example, the filtering process is not limited to a method capable of removing fine foreign substances, and for example, a bag filter, a micro filter, or a filter strainer may be used.

In one specific example, the temperature of the filtrate during the filtering process may be maintained at about 80°C to minimize inhibition of the separation process due to the viscosity of the glycol compound.

In step d, the filtrate is cooled to lower the solubility of BHET to separate BHET from the filtrate, thereby allowing BHET to crystallize and precipitate.

In one specific example, the cooling of the filtrate varies depending on the type of solvent, and generally, the crystallization reaction can be performed at a temperature 5°C to 20°C higher than the melting point of the solvent. Specifically, the cooling is performed at a temperature of -20°C to 5°C for 24 to 36 hours, through which the BHET series can be crystallized.

In one specific example, the crystallized BHET may be subjected to various solid-liquid separation means, such as a filter or a centrifuge, to separate the BHET crystals and the crystal filtrate. The colorant present in the impurities contained in the crystal filtrate may be removed by adsorption by an adsorber.

Step e

In the present invention, after performing step d, a solvent regeneration step may be additionally performed, which is a step of reusing the glycol compound regenerated in step d in step a.

In one embodiment, the crystal filtrate separated in step d contains a glycol compound, which may be referred to as a regenerated glycol compound.

The above-mentioned regenerated glycol compound can be reused in step a.

In the present invention, the recovered tarpaulin decomposition product is added at a certain content ratio during the manufacture of a recycled PVC sheet, thereby suppressing the protrusion of PET fibers on the surface of the sheet, thereby producing a recycled PVC sheet with excellent mechanical properties and a well-controlled surface condition.

Recycled PVC Sheet

Furthermore, the present invention relates to a recycled PVC sheet comprising a tarpaulin decomposition product manufactured by a method for recycling PVC tarpaulin.

The recycled PVC sheet according to the present invention comprises PVC;

The aforementioned tarpaulin decomposition product; and

It can be manufactured through a step of molding a waste resin composition including an additive.

In one specific example, the content of tarpaulin decomposition product may be 5 to 100 parts by weight relative to 100 parts by weight of PVC.

In one specific embodiment, the additive may include one or more selected from the group consisting of fillers, plasticizers and lubricants.

Calcium carbonate, etc. can be used as the filler, diisononyl phthalate, etc. can be used as the plasticizer, and at least one selected from the group consisting of PE wax and stearic acid, etc. can be used as the activator.

In one specific example, the sheet can be manufactured through a forming process such as compounding, roll milling, etc.

The sheet according to the present invention has a good surface condition because the fiber tissue does not protrude to the outside, and can be recycled into a product with equivalent mechanical properties.

The recycled PVC sheet according to the present invention can be applied to purposes such as flooring materials, waterproofing sheets, and interfloor barriers in buildings.

Hereinafter, the present invention will be described with reference to FIGS. 1 and 2.

Figure 1 is a process schematic diagram for a method for recycling waste PVC tarpaulin.

As shown in FIG. 1, the present invention can recycle waste PVC tarpaulin through the steps of: introducing a pulverized waste PVC tarpaulin into a first reactor together with ethylene glycol and a catalyst to perform a glycol decomposition reaction; separating a solid residue and a filtrate (including BHET compounds dissolved in unreacted glycol compounds) from the reactants through a solid-liquid separation process; washing and drying the solid residue; and performing a separation process on the filtrate to recover bis-2-hydroxy ethyl terephthalates (BHET compounds) and regenerating a glycol compound, which is a solvent.

In addition, Fig. 2 shows a system applied to a method of recycling waste PVC tarpaulin.

In addition, as shown in FIG. 2, the system used for recycling waste PVC tarpaulin may be composed of a first reactor (100) in which a glycol decomposition reaction of waste PVC tarpaulin is performed, a filter (10) in which a solid-liquid separation process is performed on the reactant produced in the first reactor, a second reactor (200) in which a separation process is performed to separate solid residue and filtrate from the reactant obtained through the solid-liquid separation process, a washer (20) and dryer (30) in which the solid residue is washed and dried, and a solid-liquid separation means (60). In addition, the products produced by the system are tarpaulin decomposition products (40), BHETs (50), and glycol compounds (70).

First, the crushed PVC tarpaulin and the catalyst are fed into the first reactor (100), and then the glycol compound is fed and reacted so that the weight ratio of the PVC tarpaulin crushed and the glycol compound is 1:4 to 1:100. In the first reactor, a glycol decomposition reaction occurs, and the PET composition of the PVC tarpaulin is decomposed to generate BHET products, etc.

The reactant in the first reactor moves to a filter (10), and a solid-liquid separation process is performed in the filter (10). In the filter (10), a solid residue and a filtrate are separated. The solid residue is sequentially passed through a washer (20) and a dryer (30), and after being washed and dried, respectively, it can be recovered as a tarpaulin decomposition product (40). The tarpaulin decomposition product (40) includes PVC, fillers, plasticizers, and lubricants. In addition, the filtrate is moved to a second reactor (200) for the recovery of BHET types and the regeneration of glycol compounds.

In the second reactor (200), crystallization and precipitation reactions are performed through cooling. The crystallization reaction can be performed at -20°C to 5°C. The precipitated BHET (50) can be recovered using various solid-liquid separation means (60) such as a filter or a centrifuge. The glycol compound (70) remaining after recovering the BHET (50) can be reused as a solvent for the glycol decomposition reaction performed in the first reactor.

In the present invention, a recycled sheet can be manufactured by adding tarpaulin decomposition material (40) at a certain content ratio.

Hereinafter, the present invention will be described in more detail through examples according to the present invention, but the scope of the present invention is not limited by the examples presented below.

Example

Example 1. Pretreatment (crushing) of tarpaulin

PVC tarpaulin is a composite plastic structure in the form of woven PET fibers coated with PVC fabric. In this example, PVC tarpaulin having a composition of PET fibers of about 15 wt% was used.

In order to improve the reactivity of the glycol decomposition reaction, as shown in Fig. 3, waste PVC tarpaulin was crushed to 3 mm or less to crush the PET fiber tissue within the PVC tarpaulin and mechanically separate the PVC fabric and PET fiber to a certain extent (production of crushed tarpaulin).

The tarpaulin pulverized material was recovered and used as a reactant for glycol decomposition reaction.

Example 2. Removal of PET fibers from waste PVC tarpaulins through glycol decomposition using betaine as a catalyst

Glycol decomposition reaction was performed to remove PET fibers from waste PVC tarpaulin.

Glycol decomposition reaction was performed in a flask reactor (1 L), and the tarpaulin pulverized product manufactured in Example 1 was used as a raw material. In addition, ethylene glycol was used as a solvent and betaine was used as a catalyst.

The ratio of tarpaulin pulverized material to solvent was 2% (w/v) and added to the reactor, and 0.5% betaine (catalyst/PET, w/w ratio) was added, and then the glycol decomposition reaction was performed at 190°C.

After glycol decomposition, the tarpaulin decomposition product existing as a solid was separated using a strainer (ASTM40, stainless steel), washed, and dried to secure a sample for recycling evaluation. At this time, washing was performed using water, and drying was performed in a freeze dryer for more than 24 hours, followed by primary weight measurement, and additional drying for 12 hours until the weight did not change.

In the present invention, Fig. 4 shows the BHET conversion rate (PET decomposition rate) according to the glycol decomposition reaction time.

When the decomposition reaction was performed for 1 hour, it was confirmed that 49.5% of the PET composition of the tarpaulin crushed product was decomposed and converted into BHET. In the present invention, the above reaction product was washed and dried to secure tarpaulin decomposition product #1.

When the reaction was performed for 2 hours, it was confirmed that 98.7% of the PET composition of the tarpaulin crushed product was decomposed and converted into BHET. In the present invention, the reaction product was washed and dried to secure tarpaulin decomposition product #2.

In addition, by fixing the reaction time to 2 hours and repeating the glycol decomposition reaction 6 times, tarpaulin decomposition product #3 with a PET decomposition rate of 84.0±14.3% was secured.

The PET degradation rate is defined as the ratio of the PET composition decomposed during the glycol degradation reaction to the PET composition of the introduced sample. The decomposed PET composition was confirmed by measuring the concentration of the main product, bis(2-hydroxyethyl) terephthalate (BHET). The degradation rate was expressed as the BHET yield relative to the introduced PET, and the BHET yield relative to the introduced PET was defined as the ratio of the amount of BHET produced after the reaction to the theoretical maximum amount of BHET that could be produced in the sample (Fig. 5). The concentration of BHET present in the solvent after the reaction was measured by high performance liquid chromatography (HPLC).

HPLC analysis conditions are as follows.

The column used was a C18 column (OpitmaPak C18-51001546, 5 μm, 150 mm X 4.6 mm), and the column temperature was maintained at 25℃ during the analysis. Two mobile phases, A and B, were used. A is distilled water containing 0.1% trifluoroacetic acid and B is methanol. The flow rate was 1 mL/min. During the 27-minute analysis, the proportion of mobile phase B was maintained at 5% for 0 to 2 minutes, and the proportion of mobile phase B was varied from 5 to 57% for 2 to 18 minutes. The proportion of mobile phase B was varied from 57 to 5% for 18 to 22 minutes. Finally, the proportion of mobile phase B was maintained at 5% for 22 to 27 minutes. Chromatography was measured at a wavelength of 254 nm using a UV/Vis detector.

Example 3. Removal of PET fibers from waste PVC tarpaulins through glycol decomposition using zinc acetate as a catalyst

PET fibers in waste PVC tarpaulin were removed by the method of Example 2, except that zinc acetate (Zn(CH₃CO₂)₂) was used as a catalyst.

The ratio of tarpaulin pulverized material to solvent was 20% (w/v), and glycol decomposition reaction was performed at a temperature of 190°C using a 0.5% zinc acetate catalyst (catalyst/PET, w/w ratio).

In the present invention, FIG. 6 shows the results of tracking the PET degradation rate of a tarpaulin degradation product sample using a zinc acetate catalyst over time.

The red solid line shows the change in temperature over the reaction time. The black solid line shows the change in BHET yield during the reaction. Since 0 to 30 minutes is the preheating time, the reaction time standard was set to 0 hours for 30 minutes.

As a result of carrying out the reaction for 90 minutes, the PET decomposition rate was 100%, confirming that the PET fiber was decomposed and converted into BHET. In the present invention, the above reaction product was washed and dried to secure tarpaulin decomposition product #4.

Example 4. Production and evaluation of recycled PVC sheets using waste PVC tarpaulin decomposition products from which PET fibers have been removed

The tarpaulin crushed product manufactured in Example 1 and the tarpaulin decomposition products #1 to #4 manufactured in Examples 2 and 3 were each mixed in the composition ratios shown in Tables 1 to 3 below. Specifically, the mixing was performed at 115°C and 1300 rpm, cooled to 50°C, and then performed a roll mill process. The roll mill was performed at 180°C for 3 minutes based on 100 g to produce a sheet having a thickness of 0.50 mm.

To measure the mechanical properties of each manufactured sheet, sheets were manufactured by compressing them using a mold with a thickness of 3 mm in a press controlled at 180℃ and processed into test specimens. (Press: 180℃, 2 min (low p: 1.5 tons) / pumping 10 times / 3 min (high p: 50 tons) / 3 min (cooling)). The tensile strength and elongation were measured based on the ASTM D638 test standard, and the appearance was judged as ‘good’ when there was little fiber and ‘bad’ when there was much fiber by observing the surface of the specimen depending on whether there was an excess of fiber structure.

division Standard Mix #1 Comparative Example #1 Test #1 Test #2 PVC 100 100 100 100 RUP-110 4 4 4 4 Calcium carbonate 70 70 70 70 Diisononyl phthalate 30 30 30 30 PE wax 0.3 0.3 0.3 0.3 Stearic acid 0.2 0.2 0.2 0.2 Tarpaulin shredder - 10 - - Tarpaulin Decomposition #1 - - 10 - Tarpaulin Decomposition #2 - - - 10 premise 204.5 214.5 214.5 214.5 appearance Good error error Good tensile strength kg _f /cm ² 208 177 204 210 Elongation (%) 172 121 174 180 hardness Shore A 96.4 96.3 95.3 95.2

division Standard Mix #2 Test #3 Test #4 Test #5 PVC 100 100 100 100 RUP-110 4 4 4 4 Calcium carbonate 70 70 70 70 Diisononyl phthalate 30 30 30 30 PE wax 0.3 0.3 0.3 0.3 Stearic acid 0.2 0.2 0.2 0.2 Tarpaulin Decomposition #3 - 5 10 20 premise 204.5 209.5 214.5 224.5 appearance Good Good Good Good tensile strength kgf/cm2 207 207 212 201 Elongation (%) 144 152 157 155 hardness Shore A 95.3 95.5 96.6 95.4

division Standard Mix #3 Test #6 Test #7 PVC 100 100 100 RUP-110 4 4 4 Calcium carbonate 70 70 70 Diisononyl phthalate 30 30 30 PE wax 0.3 0.3 0.3 Stearic acid 0.2 0.2 0.2 Tarpaulin Decomposition #3 - 80 - Tarpaulin Decomposition #4 - - 100 premise 204.5 284.5 304.5 appearance Good Good Good tensile strength kgf/cm2 207 207 212 Elongation (%) 144 152 157 hardness Shore A 95.3 95.5 96.6

Experimental Example 1. Evaluation of the effect of PET fiber decomposition rate on the characteristics of recycled PVC sheets

In order to determine the effect of the decomposition rate of PET fibers on the properties of recycled PVC sheets, the appearance and physical properties of the recycled PVC sheets manufactured in Example 4 were evaluated.

Figure 7 shows a photograph of PET fibers appearing on the surface during the roll mill process during the process of manufacturing recycled PVC sheets, and Figure 8 shows an enlarged photograph of the surface of a recycled PVC sheet specimen.

Specifically, in Fig. 7, (a) is a photograph of processing a formulation manufactured according to Reference Mixture #1, (b) is a photograph of processing a formulation manufactured according to Comparative Example #1, and (c) and (d) are photographs of processing formulations manufactured according to Test #1 and Test #2, respectively. In addition, in Fig. 8, (a) to (d) are enlarged photographs of the surfaces of PVC sheet specimens manufactured according to Reference Mixture #1, Comparative Example #1, Test #1, and Test #2, respectively.

As shown in Fig. 7, it can be confirmed that the processability and the appearance of the resultant product of the blend containing tarpaulin decomposition product #2 are the same as those of the reference blend (Fig. 7d). The processability of the blend containing tarpaulin shreds is the same as those of the reference blend, but it can be confirmed that the PET fibers were not melted, resulting in poor appearance (Figs. 7b and 8b). In the case of the appearance characteristic evaluation, it can be confirmed that the appearance of the sheet containing tarpaulin decomposition product #1 had a slight increase in surface foreign matter (Fig. 8c). It can be confirmed that the appearance of the sheet containing tarpaulin decomposition product #2 was the same as that of the sheet manufactured according to the reference blend (Fig. 8d).

Additionally, Fig. 9 shows the results of evaluating the mechanical properties of recycled PVC sheet specimens.

In Fig. 9, (a) shows the results of measuring tensile strength, and (b) shows the results of measuring elongation. The experimental data are expressed as box plots from the results obtained from five repeated experiments, and the experimental results were analyzed by one-way analysis of variance (ANOVA) followed by Tukey's test. N.S. means Not significant, and *** means p-value<0.001.

As shown in Fig. 9, it can be confirmed that the properties of the recycled PVC sheet containing the tarpaulin decomposition product are at the same level as the properties of the sheet manufactured according to the standard mixing ratio. In the case of the sheet containing the tarpaulin shreds (Comparative Example #1), the tensile strength and elongation decreased compared to the standard mixing ratio. It is judged that the tensile properties decreased because the dispersed PET fibers acted as foreign substances.

Experimental Example 2. Evaluation of the Effect of Decomposition Content on the Properties of Recycled PVC Sheets

To determine the effect of tarpaulin decomposition product content on the properties of recycled PVC sheets, the appearance and mechanical properties of the recycled PVC sheets manufactured in Example 4 were evaluated.

Figures 10 and 11 show enlarged photographs of the surface of a recycled PVC sheet specimen.

Specifically, (a) to (d) in Fig. 10 are enlarged photographs of the surfaces of PVC sheet specimens manufactured according to the reference formulation #2, Test #3, Test #4, and Test #5, respectively. In addition, (a) to (c) in Fig. 11 are enlarged photographs of the surfaces of PVC sheet specimens manufactured according to the reference formulation #3, Test #6, and Test #7, respectively. The average PET degradation rate of tarpaulin decomposition product #3 is 84.0±14.3%, and the PET degradation rate of tarpaulin decomposition product #4 is 100%.

As shown in the above Figures 10 and 11, even when up to 100 phr of tarpaulin decomposition product was added to the standard mixture, no protrusion of PET fibers was observed in appearance, and it could be confirmed that the same appearance characteristics as the standard mixture were exhibited.

Additionally, Figures 12 and 13 show the results of evaluating the mechanical properties of recycled PVC sheet specimens.

As shown in Figures 12 and 13, a significant difference was observed as the amount of tarpaulin decomposition product increased, but it was confirmed that this did not affect the overall purpose of the sheet use.

100: first reactor, 10: filter, 200: second reactor, 20: washer, 30: dryer, 40: tarpaulin decomposition product, 50: BHET, 60: solid-liquid separation means, 70: glycol compound

Claims (14)

A step (step a) of subjecting a mixture comprising PVC tarpaulin shredder, a glycol compound and a catalyst to a glycolysis reaction to decompose PET fibers present in the PVC tarpaulin shredder into bis-2-hydroxyethyl terephthalates (BHETs);
A step (step b) of filtering the reaction product of step a to separate the solid residue containing the tarpaulin decomposition product and the filtrate;
A step (step c) of washing and drying the tarpaulin decomposition product separated in the above step b; and
A step (step d) of recovering BHET from the filtrate separated in the above step b and regenerating a glycol compound as a solvent,
The above catalyst is a method for recycling PVC tarpaulin containing PET fibers which is betaine.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein in step a, the glycol compound comprises at least one selected from the group consisting of ethylene glycol (EG), 1,3-propanediol (PDO) and 1,4-butanediol (BDO).
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein the weight ratio of PVC tarpaulin shreds and glycol compound in step a is 1:4 to 1:100.
delete In paragraph 1,
A method for recycling PVC tarpaulin, wherein the catalyst content is 0.065 to 3 parts by weight based on 100 parts by weight of tarpaulin crushed material.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein in step a, glycol decomposition reaction is performed at 185°C to 196°C for 10 minutes to 4 hours.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein the BHET type comprises at least one selected from the group consisting of bis-2-hydroxyethyl terephthalate (BHET), bis-3-hydroxypropyl terephthalate (BHPT), and bis-4-hydroxybutyl terephthalate (BHBT).
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein in step b, filtration is performed using a bag filter, a micro filter or a filter strainer.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein filtration in step b is performed at a temperature of 80°C or higher.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, wherein in step b, the filtrate contains 0.2 to 4 wt% of BHET compounds and unreacted glycol compounds.
In paragraph 1,
Step d is a method for recycling PVC tarpaulin containing PET fibers, wherein the temperature of the filtrate is cooled to crystallize and then precipitate BHET.
In paragraph 1,
A method for recycling PVC tarpaulin containing PET fibers, further comprising a step (step e) of reusing the glycol compound recycled in step d in step a.
PVC;
Tarpaulin decomposition product manufactured by the method for recycling PVC tarpaulin according to Article 1; and
It is manufactured by the step of molding a waste resin composition containing an additive,
A recycled PVC sheet having a content of the above tarpaulin decomposition product of 5 to 100 parts by weight relative to 100 parts by weight of PVC.
In Article 13,
A recycled PVC sheet, wherein the additive comprises at least one selected from the group consisting of fillers, plasticizers and lubricants.