Heat-resistant compound composition for fibers with biodegradability in soil and fibers with biodegradability in soil using the same

Abstract

The present invention provides a heat-resistant compound composition for soil-biodegradable fibers comprising polypropylene, amylopectin starch and amylose starch as thermoplastic starches, and a trace amount of metal. The compound comprising polypropylene and thermoplastic starch according to the present invention exhibits high biodegradability under soil conditions, so that when commercialized as a fiber material, it may not cause carbon emissions or waste management problems.

Description

Technology Field

[0001] The present invention relates to a heat-resistant compound composition for fibers with secured soil biodegradability and a soil biodegradable fiber manufactured using the same. Background Technology

[0002] Amidst the continuing rise in interest regarding biomass and biodegradable plastics in conjunction with recent plastic waste and carbon neutrality issues, the problem of disposable nonwoven fabric waste has rapidly emerged during the COVID-19 pandemic. Disposable nonwoven fabrics are not recycled due to pathogen contamination and hygiene concerns, and are therefore entirely incinerated, continuously causing carbon emissions and waste management issues. Consequently, attempts have been made to use PLA (Polylactic acid) as a biodegradable fiber material, and it is currently in the commercialization stage. However, PLA has the characteristic that while it composts under industrial composting conditions (above 58°C), it does not biodegrade under actual soil conditions.

[0003] Recently, there has been a movement to change biodegradation standards to actual soil conditions (25°C) not only in Europe but also in the United States and Asian countries. In particular, earlier this year, the Ministry of Environment announced an implementation plan to stop issuing new biodegradation certifications for single-use products, as PLA materials do not biodegrade under soil conditions.

[0004] Accordingly, there is a growing need to develop fiber compounds capable of biodegradation under actual soil conditions as well as industrial composting conditions. The problem to be solved

[0005] The present invention aims to provide a heat-resistant compound composition for fibers with secured soil biodegradability and a soil biodegradable fiber manufactured using the same.

[0006] The above and other objects and advantages of the present invention will become apparent from the following description describing preferred embodiments. means of solving the problem

[0007] The present invention provides a heat-resistant compound composition for soil-biodegradable fibers comprising polypropylene, amylopectin starch and amylose starch, and a trace amount of metal.

[0008] In addition, the present invention provides a soil biodegradable fiber manufactured using the above composition. Effects of the invention

[0009] The compound containing polypropylene and thermoplastic starch according to the present invention exhibits high biodegradability under soil conditions, so when commercialized as a fiber material, it may not cause carbon generation and waste management problems.

[0010] However, the effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0011] Figure 1 is an SEM image of a fiber prepared using the pellet-type compound of Example 1. Specific details for implementing the invention

[0012] The present invention provides a heat-resistant compound composition for soil-biodegradable fibers comprising polypropylene, amylopectin starch and amylose starch as thermoplastic starches, and a trace amount of metal.

[0013] According to one embodiment of the present invention, the composition may comprise 50 to 80 weight% of polypropylene; 2.0 to 20 weight% of amylopectin starch; 5.0 to 25 weight% of amylose starch; and 10 to 100 ppm of metal based on the total weight of the composition.

[0015] The starch used as a naturally biodegradable material in the present invention is extracted from corn, potatoes, rice, sweet potatoes, etc., and consists mainly of straight-chain amylose starch and branched-chain amylopectin starch.

[0016] In the present invention, the starch may be a modified starch in which amylopectin starch is converted into amylose starch by chemical treatment.

[0017] Biodegradability can be improved as the relative content of amylose starch compared to amylopectin starch increases.

[0018] According to one embodiment of the present invention, the content of amylose starch may be 10 to 90%, preferably 50 to 90%, with respect to the total weight of the amylopectin starch and amylose starch. When the content of amylose starch is 90%, the biodegradability may be maximum, and it is impossible to increase the relative content of amylose starch beyond that.

[0019] According to one embodiment of the present invention, the amylopectin starch and amylose starch may form esterified starch by attaching an ester functional group to the terminal group.

[0020] Esterified starch can impart heat resistance to starch and durability to compounds.

[0021] According to one embodiment of the present invention, the ester functional group may be bonded to the terminal groups of amylopectin starch and amylose starch in an amount of 0.5 to 6 weight%, preferably 2.00 to 3.50 weight%, based on the total weight of the composition. As the ester group increases, productivity and heat resistance are ensured, but it is difficult to induce an amount of 6 weight% or more.

[0022] In the present invention, the starch may be a plasticized thermoplastic starch.

[0024] According to one embodiment of the present invention, the metal may be selected from the group consisting of Ca, K, Cu, Zn, Mg, Fe, Mn, and Ni.

[0025] A minute amount of metal is added mixed with thermoplastic starch to induce the soil biodegradation of polypropylene.

[0026] As a result of evaluating the biodegradability of copper, zinc, and potassium, it was confirmed that K (potassium) relatively more accelerates the degradation of polypropylene under industrial and soil conditions.

[0027] Therefore, it is desirable that the metal be K.

[0028] The metal content is preferably 10 ppm to 100 ppm, and most preferably 70 ppm to 100 ppm.

[0029] As a result of evaluating biodegradability according to metal content, optimal biodegradability was obtained when the metal content was 70 ppm, and it was confirmed that biodegradability actually decreased when the content exceeded 100 ppm.

[0030] In addition, the present invention provides a soil biodegradable fiber manufactured using the above composition.

[0032] Hereinafter, the structure of the present invention and the resulting effects are to be explained in more detail through specific embodiments and comparative examples. However, these embodiments are intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[0034] [ingredient]

[0035] Starch extracted from potatoes (OTTO potatoes from Youngheung Food Co., available on the market) was used as the starch powder.

[0036] Thermoplastic starch (TPS) was prepared by mixing glycerol, a plasticizer, with potato starch. The mixed glycerol was present in a ratio of 20-35 wt.%, and the TPS was produced using a twin-screw extruder.

[0038] <Examples 1 to 12>

[0039] Preparation of compound composition

[0040] A compound composition was prepared with the composition listed in Table 1 below.

[0041] Manufacturing of compound

[0042] The above compound composition was extruded to produce a pellet-shaped compound. At this time, a twin extruder with a screw diameter of 44 mm was used, the extrusion speed was 300 rpm, the raw material input speed was 40 rpm, the barrel temperature was 150℃, the die nozzle diameter was 3.5 mm, the heat exchange method was countercurrent, and the cooling water temperature was 20℃.

[0044] <Comparative Example 1>

[0045] A compound was prepared in the same manner as in Example 1, except that no metal was used.

[0047] <Experimental Example 1> Evaluation of Biodegradability

[0048] Samples obtained by cutting the pellet-type compounds prepared in Examples 1 to 12 and Comparative Example 1 into 2×2 cm pieces were evaluated by measuring the amount of carbon dioxide generated by the standard sample (cellulose) and the test sample over 90 days according to KS M ISO 14855-1 (Method for measuring aerobic biodegradability of plastics under composting conditions) and using the following formula, and the results are shown in Table 1 below.

[0049] Biodegradability (%) = (Amount of generated carbon dioxide / Amount of theoretical carbon dioxide) x 100

[0051] In addition, the amount of carbon dioxide generated by the standard sample (cellulose) and the test sample was measured over 180 days according to KS M ISO 17556 (measurement of carbon dioxide generation or oxygen consumption) under general soil conditions, evaluated by the following formula, and the results are shown in Table 1 below.

[0052] Biodegradability (%) = (Amount of generated carbon dioxide / Amount of theoretical carbon dioxide) x 100

[0054] <Experimental Example 2> Heat Resistance Evaluation

[0055] For the pellet-type compounds prepared in Examples 1 to 12 and Comparative Example 1 above, the TGA Curve was measured, and the pyrolysis temperature was measured based on the temperature at which a weight loss of 5% or more was reached, and the results are shown in Table 1 below. A TA Instrument TGA Q500 was used for measuring the TGA Curve.

[0057] Compound composition (wt%) Metal (ppm) Composition (wt%) Biodegradability (180 days) heat resistance Cu Zn K polypropylene Amylopectin starch Amylose starch ester functional group Industrial composting (ISO 14855-1) Soil conditions (ISO 17556) Thermal decomposition temperature (°C) Comparative Example 1 0 0 0 75.00 17.50 7.50 0.00 26.4 13.1 203 Example 1 100 0 0 75.00 17.50 7.50 0.00 53.2 33.1 204 Example 2 0 100 0 75.00 17.50 7.50 0.00 61.1 41.7 202 Example 3 0 0 100 75.00 17.50 7.50 0.00 73.8 53.8 203 Example 4 0 0 70 75.00 17.50 7.50 0.00 84.2 58.6 202 Example 5 0 0 10 75.00 17.50 7.50 0.00 62.7 44.4 203 Example 6 0 0 150 75.00 17.50 7.50 0.00 59.8 59.3 202 Example 7 0 0 300 75.00 17.50 7.50 0.00 58.6 52.2 205 Example 8 0 0 70 75.00 12.50 12.50 0.00 86.5 64.3 203 Example 9 0 0 70 75.00 7.50 17.50 0.00 88.9 71.4 202 Example 10 0 0 70 75.00 2.50 22.50 0.00 91.3 76.2 205 Example 11 0 0 70 75.00 2.13 22.13 0.75 90.9 79.3 216 Example 12 0 0 70 75.00 1.75 21.75 1.50 90.1 80.0 228

[0059] From the results of Examples 1 to 3, it can be seen that among copper, zinc, and potassium, K (potassium) can relatively more promote the decomposition of polypropylene even under industrial and soil conditions.

[0060] From the results of Examples 3 to 7, it can be seen that optimal biodegradability is obtained when 70 ppm of K (potassium) is added, and that biodegradability actually decreases when it exceeds 100 ppm.

[0061] From the results of Examples 4, 8, 9, and 10, it can be seen that the biodegradability is maximum when the content of amylose starch relative to the total weight of amylopectin starch and amylose starch is 90%.

[0062] From the results of Examples 11 and 12, it can be seen that heat resistance is improved with the application of esterified starch.

[0064] <Experimental Example 3> Evaluation of Fiber Processability and Mechanical Properties

[0065] The pellet-type compounds prepared in Examples 1 to 12 and Comparative Example 1 were processed into fibers, and the fiber processability and mechanical properties were evaluated, and the results are shown in Table 2 below.

[0067] Fiber properties Fiber processability mechanical properties Annual ratio (%) Island (de) Radiation yield (%) Tensile strength (g / d) Elongation at break (%) Comparative Example 1 185 3.78 66 1.12 105 Example 1 145 4.65 50 0.96 65 Example 2 130 4.33 52 0.75 75 Example 3 140 3.98 53 0.77 80 Example 4 160 3.77 46 0.63 85 Example 5 175 3.45 53 0.82 80 Example 6 115 3.89 37 0.71 100 Example 7 90 3.66 23 0.53 95 Example 8 160 3.43 68 0.54 135 Example 9 155 4.11 67 0.95 125 Example 10 160 4.08 59 0.98 130 Example 11 245 2.78 78 1.13 135 Example 12 ≥300 2.18 84 1.92 225

[0069] As shown in Table 2 above, the fibers processed using the pellet-type compounds prepared in Examples 1 to 12 exhibited fiber processability and mechanical properties equivalent to those of the fibers processed using the pellet-type compound prepared in Comparative Example 1.

Claims

Claim 1 A heat-resistant compound composition for soil-biodegradable fibers comprising 50 to 80 weight% polypropylene, 2.0 to 20 weight% amylopectin starch and 5.0 to 25 weight% amylose starch, and 10 to 100 ppm of a metal selected from the group consisting of Cu, Zn and K. Claim 2 delete Claim 3 delete Claim 4 A heat-resistant compound composition for soil biodegradable fibers according to claim 1, wherein the metal is K. Claim 5 A heat-resistant compound composition for soil biodegradable fibers according to claim 1, wherein the content of amylose starch is 10 to 90% with respect to the total weight of the amylopectin starch and amylose starch. Claim 6 A heat-resistant compound composition for soil biodegradable fibers according to claim 1, wherein the amylopectin starch and amylose starch have ester functional groups bonded to their terminal groups. Claim 7 A heat-resistant compound composition for soil biodegradable fibers according to claim 6, wherein the ester functional group is bonded to the terminal groups of amylopectin starch and amylose starch in an amount of 0.5 to 6 weight% with respect to the total weight of the composition. Claim 8 A soil biodegradable fiber manufactured using a heat-resistant compound composition for soil biodegradable fibers according to any one of claims 1, 4 to 7.

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