Method for producing TPEE composition comprising recycled TPEE

Abstract

The present invention is technically sufficient for a method for manufacturing a TPEE composition containing recycled TPEE, comprising: a raw material preparation step of preparing a TPEE (thermoplastic polyester elastomer) chip, a recycled TPEE chip, and a compatibilizer, respectively; and a composition blending step of feeding the TPEE chip, the recycled TPEE chip, and the compatibilizer into an extruder and gradually increasing the temperature of the extruder from 180°C to 240°C to blend the TPEE composition. By doing so, by blending the recycled TPEE chip with the TPEE chip using a compatibilizer, it is possible to obtain a TPEE composition containing recycled TPEE that prevents environmental pollution and reduces manufacturing costs.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a TPEE composition containing recycled TPEE, and more specifically, to a method for manufacturing a TPEE composition containing recycled TPEE that enables environmental pollution prevention and reduced manufacturing costs by blending recycled TPEE chips with TPEE chips using a compatibilizer. Background Technology

[0002] Thermoplastic elastomers (TPEs) are high-performance materials that combine the elasticity of rubber with the moldability of plastic. Particularly due to their light specific gravity, they are being utilized in a wide range of fields—including automobiles, home appliances, construction materials, and clothing—to replace culcanized rubber and polyvinyl chloride (PVC), making them one of the materials expected to see a further increase in demand. Furthermore, TPEs possess excellent recyclability, making them a suitable material for addressing carbon neutrality, a key issue recently in Europe and Korea. As such, they can be utilized in a broad range of sectors, including automobiles and everyday materials, by replacing culcanized rubber and PVC.

[0003] With global interest in the severity of environmental pollution and the development of eco-friendly industries, the necessity of a circular economy is being highlighted, along with the ease of recyclability and eco-friendliness of non-crosslinked thermoplastic elastomers. Here, the circular economy refers to an economic system where materials introduced into the economy are not discarded but are repeatedly used as useful resources within the economy, rather than a linear flow of materials from 'consumption to disposal'. Therefore, among thermoplastic elastomers, thermoplastic polyester elastomers (TPEE) are attracting attention as materials applicable to this circular economy.

[0004] TPEE has the advantage of being recyclable both mechanically and chemically. In particular, its excellent processability makes simple mechanical recycling easy, which serves as a driving force for cost competitiveness in the process. Therefore, there is a need to develop high-performance TPEE materials containing a high content of recycled TPEE to meet the environmental and human-friendly consumption trends. The problem to be solved

[0005] The present invention was devised to solve the above-mentioned problems, and aims to provide a method for manufacturing a TPEE composition containing recycled TPEE that can prevent environmental pollution and reduce manufacturing costs by blending recycled TPEE chips with TPEE chips using a compatibilizer. means of solving the problem

[0006] The above objective is achieved by a method for manufacturing a TPEE composition containing recycled TPEE, characterized by comprising: a raw material preparation step of preparing a TPEE (thermoplastic polyester elastomer) chip, a recycled TPEE chip, and a compatibilizer, respectively; and a composition blending step of feeding the TPEE chip, the recycled TPEE chip, and the compatibilizer into an extruder and gradually increasing the temperature of the extruder from 180°C to 240°C to blend the TPEE composition.

[0007] Here, in the raw material preparation step, it is preferable to prepare 50 to 60 parts by weight of the TPEE chip, 40 to 50 parts by weight of the recycled TPEE chip, and 5 to 10 parts by weight of the compatibilizer.

[0008] Additionally, the extruder comprises: a hopper section into which the TPEE chip, the recycled TPEE chip, and the compatibilizer are fed; a nozzle section connected to the hopper section for melting the TPEE chip, the recycled TPEE chip, and the compatibilizer; a mold section for mixing and compressing the TPEE chip, the recycled TPEE chip, and the compatibilizer melted in the nozzle section to form a TPEE composition; and a discharge section connected to the mold section for discharging the TPEE composition to the outside; wherein the temperature of the hopper section is set to 180 to 190°C, the temperature of the nozzle section is set to 190 to 200°C, the temperature of the mold section is set to 200 to 210°C, and the temperature of the discharge section is set to 210 to 240°C, and the TPEE chip, the recycled TPEE chip, and the compatibilizer are blended at a speed of 50 rpm. Effects of the invention

[0009] As described above, according to the present invention, by blending recycled TPEE chips with TPEE chips using a compatibilizer, it is possible to obtain a TPEE composition containing recycled TPEE that can prevent environmental pollution and reduce manufacturing costs. Brief explanation of the drawing

[0010] FIG. 1 is a flowchart of a method for preparing a TPEE composition according to an embodiment of the present invention, and Figure 2 is an extrusion photograph of a TPEE composition, and Figure 3 is a graph showing the melt index of the TPEE composition according to the extruder temperature, and Figure 4 is a graph of the thermal decomposition temperature of the TPEE composition according to the extruder temperature, and Figure 5 is a graph of the amount of tar produced by the TPEE composition according to the extruder temperature, and Figure 6 is a TGA analysis graph of the TPEE composition according to extruder temperature, and Figure 7 is a graph showing the Tg and Tm analysis of the TPEE composition according to the extruder temperature, and Figure 8 is a DSC analysis graph of the TPEE composition according to extruder temperature, and Figure 9 is a graph showing the melt index of the TPEE composition according to the extrusion speed, and Figure 10 is a graph of the thermal decomposition temperature of a TPEE composition according to the extrusion speed, and FIG. 11 is a graph of the amount of tar produced by a TPEE composition according to the extrusion speed, and Figure 12 is a TGA analysis graph of a TPEE composition according to extrusion speed, and Figure 13 is a graph showing the Tg and Tm analysis of the TPEE composition according to the extrusion speed, and Figure 14 is a DSC analysis graph of the TPEE composition according to extrusion speed, and Figure 15 is a photograph showing the tensile strength of a TPEE composition before and after measurement according to extruder temperature, and Figure 16 is a graph of the tensile strength and elongation of the TPEE composition according to the extruder temperature. Specific details for implementing the invention

[0011] Hereinafter, the technical concept of the present invention will be explained in more detail using the attached drawings. The attached drawings are merely examples illustrated to explain the technical concept of the present invention in more detail, and therefore the technical concept of the present invention is not limited to the form of the attached drawings.

[0013] Polymer blending is an effective method for improving the balance between physical properties and costs by combining different polymer materials, and it can be utilized to realize new polymer properties or introduce eco-friendly recycling processes. However, the properties of blended polymers often degrade due to incompatibility between different polymers; to address this, compatibilizers can be used to significantly improve compatibility by increasing the bonding strength at the polymer interface and reducing interfacial tension.

[0015] A method for preparing a TPEE composition including recycled TPEE according to an embodiment of the present invention includes a raw material preparation step (S100) and a composition blending step (S200) as shown in FIG. 1.

[0017] First, the raw material preparation step (S100) means the step of preparing TPEE chips, recycled TPEE chips, and a compatibilizer, respectively.

[0018] TPEE chips refer to polymers generally used in the manufacture of TPEE (thermoplastic polyester elastomer) films that have been processed into chip form, meaning TPEE polymers that have never undergone film processing and are not recycled are processed into chip form. It is preferable to add 50 to 60 parts by weight of such TPEE chips; if the TPEE chips are less than 50 parts by weight, the durability of the final TPEE composition may be reduced, and if the TPEE chips exceed 60 parts by weight, it becomes difficult to reduce the manufacturing costs of the TPEE composition and the products produced using the TPEE composition.

[0019] Recycled TPEE chips refer to recycled elastic materials, meaning that the polymer obtained by feeding TPEE waste into an extruder and extruding it at 200°C or higher is processed into a chip form. Thermoplastic polyester elastomer waste (TPEE) discarded after use in various industries is collected and fed into an extruder at 200°C or higher to undergo a recycling process and transform into recycled TPEE chips that can be compressed into a chip form. If the temperature of the extruder is below 200°C, the TPEE waste may not melt completely, and proper extrusion may not occur.

[0020] It is preferable to add 40 to 50 parts by weight of such recycled TPEE chips. If less than 40 parts by weight of recycled TPEE chips are added, it is difficult to reduce the manufacturing cost of the TPEE composition and the purpose of environmental protection cannot be achieved. If more than 50 parts by weight of recycled TPEE chips are added, there is a disadvantage that the durability of the TPEE composition is reduced.

[0021] Here, it is preferable that the TPEE chips and recycled TPEE chips be cut so that their diameter and height are each 1 to 2 cm. If the diameter and height of the TPEE chips and recycled TPEE chips are less than 1 cm, the shape of the TPEE chips and recycled TPEE chips may be distorted during the cutting process, and if they exceed 2 cm, the TPEE chips and recycled TPEE chips may not be blended uniformly.

[0022] At this time, the TPEE chips and recycled TPEE chips must be cut to the same length. However, if the cutting length is not uniform, the amount of TPEE chips and recycled TPEE chips fed from the extruder pump during the subsequent process may not be uniform, which may cause problems such as increased RPM and vibration of the extruder screw.

[0023] A compatibilizer is an additive that provides compatibility between different raw materials, and in the present invention, it is added to provide compatibility between TPEE chips and recycled TPEE chips. Unlike conventional additives, such a compatibilizer reduces interfacial tension and increases interfacial adhesion, and contributes to stabilizing the morphology and dispersibility in a mixed state of TPEE chips and recycled TPEE chips.

[0024] Such compatibilizers are preferably selected from the group consisting of anhydride modified ethylene copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-butyl acrylate copolymer, and mixtures thereof, among which ethylene-methyl acrylate-glycidyl methacrylate copolymer is most preferred but is not limited thereto.

[0025] In addition, it is preferable to add 5 to 10 parts by weight of a compatibilizer. If the amount of compatibilizer is less than 5 parts by weight, proper compatibilization between the TPEE chip and the recycled TPEE chip may not occur, and consequently, crosslinking performance may be reduced. If the amount of compatibilizer exceeds 10 parts by weight, the crosslinking time becomes longer, and as the amount of compatibilizer increases, the ratio of the TPEE chip to the recycled TPEE chip decreases, which may lower the durability of the TPEE composition.

[0027] The composition blending step (S200) means a step of blending the TPEE composition by feeding TPEE chips, recycled TPEE chips, and a compatibilizer into an extruder and gradually increasing the temperature of the extruder from 180°C to 240°C.

[0028] The TPEE chips, recycled TPEE chips, and compatibilizer prepared through the raw material preparation step (S100) are each fed into an extruder, and the TPEE chips, recycled TPEE chips, and compatibilizer are uniformly mixed within the extruder to finally inject the TPEE composition. Specifically, the TPEE chips and recycled TPEE chips melt and mix with each other within the extruder, and at this time, the TPEE chips and recycled TPEE chips, which have different physical properties, are easily blended by the compatibilizer. The TPEE composition blended through the extruder in this way can be injected in the shape of pellets to facilitate storage.

[0029] Here, the extruder uses an extruder comprising: a hopper section into which TPEE chips, recycled TPEE chips, and a compatibilizer are fed; a nozzle section connected to the hopper section for melting the TPEE chips, recycled TPEE chips, and a compatibilizer; a mold section for mixing and compressing the TPEE chips, recycled TPEE chips, and a compatibilizer melted in the nozzle section to form a TPEE composition; and a discharge section connected to the mold section for discharging the TPEE composition to the outside. The temperature is gradually increased from 180°C to 240°C as it moves toward the hopper section, the nozzle section, the mold section, and the discharge section to blend the TPEE composition.

[0030] At this time, the temperature of the hopper section is set to 180 to 190°C, the temperature of the nozzle section is set to 190 to 200°C, the temperature of the mold section is set to 200 to 210°C, and the temperature of the discharge section is set to 210 to 240°C, and the TPEE chips, recycled TPEE chips, and compatibilizer are blended while moving sequentially through the hopper section, nozzle section, and mold section at a speed of 50 rpm. If the temperature of the extruder is below 180°C, the TPEE chips and recycled TPEE chips are not completely melted, making complete blending difficult, and if the temperature of the extruder exceeds 240°C, the physical properties of the TPEE composition may deteriorate.

[0032] Example 1 Example 2 Example 3 Example 4 Commercial agent LotaderAX8900 (parts by weight) 10 10 10 10 TPEE (parts by weight) 60 60 60 60 Recycled TPEE (parts by weight) 40 40 40 40 Discharge temperature (°C) 210 220 230 240 Extruder speed (rpm) 50 50 50 50

[0034] Table 1 shows the preparation of TPEE compositions by varying the discharge temperature of the extruder. As shown in Table 1, the sample shapes of the blended TPEE compositions are as shown in Figure 2, and it can be observed that the apparent density tends to decrease as the discharge temperature increases. In particular, this difference was clearly observed when 5g of each sample from Examples 1 to 4 was placed in vials. This is believed to be the result of an air layer being formed inside due to rapid shrinkage during the cooling process after the high-temperature process, or of gas generated by the thermal decomposition of the raw material creating an internal space.

[0036] Figure 3 shows the melt index according to the temperature of the discharge section. Conventional TPEE has a significantly low viscosity, flowing like a solution when melted, making it unsuitable for the spinning process. To address this, the present invention prepared a TPEE composition using a compatibilizer. Specifically, 10 parts by weight of the compatibilizer were added, and the temperature of the extruder was controlled to prepare a sample using the TPEE composition, after which the melt index was measured. Through this, the effect of process temperature on the compatibilizer and the melt index was evaluated. In the case of Examples 1 to 4, the melt indices were 21.5g / 10min, 23.6g / 10min, 25.1g / 10min, and 13g / 10min, respectively. It was confirmed that the melt index decreased compared to conventional TPEE (>50g / 10min) under all conditions, and in particular, when extruded at 240℃, the melt index decreased to 13g / 10min.

[0038] To verify changes in thermal characteristics according to process temperature, TGA (Thermo Gravimetric Analysis) and DSC (Differential Scanning Calorimetry) analyses were performed. TGA (TA instruments Inc., Q-500, USA) and DSC (TA instruments Inc., Q-100, USA) were used for the analysis, and the analysis conditions were set at a rate of 10℃ / min in the range of 80 to 900℃ for TGA and 0 to 250℃ for DSC.

[0039] Figure 4 shows the pyrolysis temperature according to process temperature, Figure 5 shows the amount of tar produced according to process temperature, Figure 6 shows a graph comparing the TGA analysis results according to process temperature, Figure 7 shows the glass transition temperature (Tg) and melting temperature (Tm) according to process temperature, and Figure 8 shows a graph comparing the DSC analysis results according to process temperature.

[0040] As a result of analyzing the pyrolysis temperature, glass transition temperature (Tg), melting temperature (Tm), and amount of tar produced during combustion of Examples 1 to 4 through TGA and DSC analysis, the pyrolysis temperature showed a similar trend regardless of the process temperature, and the glass transition temperature and melting temperature also showed no significant difference. On the other hand, it was observed that the amount of tar produced tended to decrease slightly as the process temperature increased. This is because there is only a slight difference in process temperature and the composition of the samples is identical, so no significant difference in thermal characteristics is observed.

[0042] Example 1 Example 5 Example 6 Commercial agent LotaderAX8900 (parts by weight) 10 10 10 TPEE (parts by weight) 60 60 60 Recycled TPEE (parts by weight) 40 40 40 Discharge temperature (°C) 220 220 220 Extruder speed (rpm) 50 35 65

[0044] Table 2 shows the results of a study on the differences in thermal characteristics between Example 5 and Example 6 by controlling the rotational speed of the screw during extrusion while the discharge temperature was set to 220℃. After feeding TPEE, recycled TPEE, and compatibilizer pellets into a twin-screw extruder, the hopper, nozzle, and mold sections were gradually increased from 190 to 220℃, and blending was performed with varying extruder rotational speeds of 35rpm, 50rpm, and 65rpm.

[0046] Figure 9 shows the melt index of TPEE according to the extruder rotation speed. Examples 1, 5, and 24.6 g / 10 min showed melt indices of 27 g / 10 min, 21.5 g / 10 min, and 24.6 g / 10 min, respectively, which confirms that the melt index has decreased compared to the existing TPEE (>50 g / 10 min). Additionally, it can be seen that while the melt indices of the examples show slight differences, they do not exhibit a particular trend.

[0048] Figure 10 shows the pyrolysis temperature according to extruder speed, Figure 11 shows the amount of tar produced according to extruder speed, Figure 12 is a graph comparing the TGA analysis results according to extruder speed, Figure 13 is a graph showing the glass transition temperature and melting temperature according to extruder speed, and Figure 14 is a graph comparing the DSC analysis results according to extruder speed. As shown in the graphs, the pyrolysis temperatures of the samples showed a similar trend regardless of the extruder speed, and the glass transition temperature and melting temperature also did not show a significant difference. In addition, it is determined that there is no significant difference in the amount of tar produced.

[0050] Commercial agent LotaderAX8900 (parts by weight) TPEE (parts by weight) Recycled TPEE (parts by weight) Discharge temperature (°C) Extruder speed (rpm) Injection temperature (°C) Heating time (min) Example 1-1 10 60 40 210 50 220 5 Example 1-2 10 60 40 210 50 230 4 Examples 1-3 10 60 40 210 50 240 3 Example 2-1 10 60 40 220 50 220 5 Example 2-2 10 60 40 220 50 230 4 Example 2-3 10 60 40 220 50 240 3 Example 3-1 10 60 40 230 50 220 5 Example 3-2 10 60 40 230 50 230 4 Example 3-3 10 60 40 230 50 240 3 Example 4-1 10 60 40 240 50 220 5 Example 4-2 10 60 40 240 50 230 4 Example 4-3 10 60 40 240 50 240 3

[0052] TPEE pellets were prepared based on the TPEE compositions in Table 3, and their physical properties were compared. Before use, the TPEE pellets were dried in a hot air dryer at 90°C for 24 hours. Then, the injection temperature was set, and tensile specimens were prepared for each sample using a press extruder (length / diameter: 40) to compare their physical properties. In addition, to determine the effect of injection temperature on physical properties, injection was performed after heating the samples to temperatures of 220°C, 230°C, and 240°C, and heating times of 5 minutes, 4 minutes, and 3 minutes, respectively.

[0054] 1 time 2nd time 3 times average Example 1-1 52 53 51 52.0 Examples 1-2 51 52 53 52.0 Examples 1-3 51 53 55 53.0 Example 2-1 53 54 53 53.3 Example 2-2 53 53 52 52.7 Examples 2-3 51 51 54 52.0 Example 3-1 52 52 53 52.3 Example 3-2 54 54 51 53.0 Example 3-3 52 52 53 52.3 Example 4-1 52 52 53 52.3 Example 4-2 53 54 51 52.7 Example 4-3 53 53 52 52.7

[0056] To verify the change in physical properties according to process temperature, hardness was measured as shown in Table 4. Hardness was calculated by analyzing three samples using a Shore D-type hardness tester and presenting the average. As a result, it was confirmed that all examples exhibited a hardness of 45 or higher.

[0058] Table 5, Figures 15 and 16 show the results of verifying the tensile strength and elongation of the TPEE composition. Tensile testing of the injection molded specimens was conducted according to ASTM standards, and the specimens used for measurement were made in the shape of a No. 3 dumbbell. The tensile test was performed at room temperature using a universal testing machine (UTM) at a speed of 200 mm / min. The tensile strength of the specimens made from the TPEE composition was measured five times for each sample, and the average and standard deviation of the tensile strength and elongation were calculated. A total of 12 types of samples were analyzed according to the extrusion process temperature and injection temperature.

[0060] tensile strength Shin Yul average Standard deviation average Standard deviation Example 1-1 2.174 0.503 576.44 147.93 Examples 1-2 2.141 0.385 422.60 98.80 Examples 1-3 2.065 0.368 344.87 203.03 Example 2-1 2.541 0.152 562.40 24.30 Example 2-2 2.197 0.328 480.37 81.52 Examples 2-3 2.074 0.262 429.68 139.00 Example 3-1 2.577 0.150 592.16 86.99 Example 3-2 2.079 0.231 446.13 67.93 Example 3-3 1.865 0.054 282.11 212.23 Example 4-1 2.367 0.170 534.04 33.43 Example 4-2 2.268 0.254 426.20 228.53 Example 4-3 2.028 0.363 292.63 257.18

[0062] Experimental results confirmed a tendency for tensile strength and elongation to decrease as the injection temperature increased. When comparing photographs of tensile strength measurements before and after according to extrusion and injection temperatures, as shown in Fig. 15, samples injected at 230°C and 240°C tended to fracture mostly in the grip area during the tensile test compared to the sample injected at 220°C. In particular, the sample injected at 240°C showed a higher frequency of fracture in the grip area than at 230°C, resulting in a relatively large standard deviation value. This is attributed to the significant influence of high injection temperatures on the compatibilizer.

[0063] In addition, when comparing the samples of Example 1-1, Example 1-2, Example 3-1, and Example 4-1, which were injected at 220°C, the samples of Example 2-1 and Example 3-1, which had extrusion process temperatures of 220°C and 230°C, showed the highest tensile strength and elongation. In particular, compared to Example 2-1 and Example 3-1, the standard deviation of elongation was smaller, so it was evaluated as a more stable sample.

[0065] The present invention is not limited to the embodiments described above, and its scope of application is diverse. Furthermore, it is understood that various modifications are possible without departing from the essence of the invention as claimed in the claims. Explanation of the symbols

[0066] S100: Raw material preparation stage S200: Composition blending step

Claims

Claim 1 A method for manufacturing a TPEE composition containing recycled TPEE, characterized by comprising: a raw material preparation step of preparing a TPEE (thermoplastic polyester elastomer) chip, a recycled TPEE chip, and a compatibilizer, respectively; and a composition blending step of feeding the TPEE chip, the recycled TPEE chip, and the compatibilizer into an extruder and gradually increasing the temperature of the extruder from 180°C to 240°C to blend the TPEE composition. Claim 2 A method for manufacturing a TPEE composition containing recycled TPEE according to claim 1, wherein the raw material preparation step comprises preparing 50 to 60 parts by weight of the TPEE chip, 40 to 50 parts by weight of the recycled TPEE chip, and 5 to 10 parts by weight of the compatibilizer. Claim 3 A method for manufacturing a TPEE composition containing recycled TPEE according to claim 1, wherein the extruder comprises: a hopper section into which the TPEE chip, the recycled TPEE chip, and the compatibilizer are fed; a nozzle section connected to the hopper section for melting the TPEE chip, the recycled TPEE chip, and the compatibilizer; a mold section for mixing and compressing the TPEE chip, the recycled TPEE chip, and the compatibilizer melted in the nozzle section to form a TPEE composition; and a discharge section connected to the mold section for discharging the TPEE composition to the outside. Claim 4 A method for manufacturing a TPEE composition containing recycled TPEE according to claim 3, wherein the temperature of the hopper section is set to 180 to 190℃, the temperature of the nozzle section is set to 190 to 200℃, the temperature of the mold section is set to 200 to 210℃, and the temperature of the discharge section is set to 210 to 240℃, and the TPEE chip, the recycled TPEE chip, and the compatibilizer are blended at a speed of 50 rpm.

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