Non-toxic biodegradable antistatic film and manufacturing method thereof

Abstract

A non-toxic biodegradable antistatic film may include poly (3 -hydroxy propionate) produced from a plant-derived raw material by a bioprocess and an antistatic agent. A method for manufacturing a non-toxic biodegradable antistatic film includes a first process of introducing poly (3 -hydroxy propionate) produced from a plant-derived raw material by a bioprocess and an antistatic agent into a solvent to prepare a mixture, a second process of heating and blending the mixture, and a third process of applying the heated and blended mixture to a substrate to produce a film.

Description

[0001] NON-TOXIC BIODEGRADABLE ANTISTATIC FILM AND MANUFACTURING

[0002] METHOD THEREOF

[0003] BACKGROUND

[0004] 1. Technical Field

[0005]

[0001] The present invention relates to a non-toxic biodegradable antistatic film, and a method for manufacturing the same, more particularly, to a biodegradable antistatic film with non-toxicity to a human body and biodegradability implemented using poly 3- hydroxy propionate, as well as a method for manufacturing the same.

[0006] 2. Background Art

[0007]

[0002] In general, a polymer compound easily generates static electricity due to friction or the like, and waste or dust is adhered to the polymer compound and may damage an appearance thereof. Therefore, it needs to impart antistatic function to the polymer compound. Specifically, in the case where a polymer compound is used for packaging a semiconductor product or the like, such antistatic function is very' important.

[0008] [3] However, plastic products such as polyethylene, polystyrene, polypropylene or polyvinyl chloride, etc. used in a wide range of different applications such as food packaging, building materials or home appliances have deteriorated degradability in the natural world. As a result, there is a problem causing environmental destruction, for example, that the plastic residue affects the ecosystem of living things, and the like.

[0009]

[0004] As a result of repeating studies to overcome the above problem, it was confirmed that, if an antistatic film is produced using poly 3-hydroxy propionate, an ecofriendly antistatic film with no toxicity to a human body and biodegradability can be produced, and thus the present invention was completed.

[0005] (Patent Document 1) Korean Registered Patent Publication No. 10-0856627 (August 28, 2008)

[0010] (Patent Document 2) Korean Registered Patent Publication No. 10-0845687 (July 4, 2008)

[0011] SUMMARY

[0012]

[0007] An object of the present invention is to provide a non-toxic biodegradable antistatic film, and a method for manufacturing the non-toxic biodegradable antistatic film.

[0013]

[0008] To achieve the above object, according to an aspect of the present invention, there is provided a non-toxic biodegradable antistatic film, including: poly (3 -hydroxy propionate) produced from a plant-derived raw material by a bioprocess; and an antistatic agent.

[0014]

[0009] The poly(3-hydroxy propionate) may have a molecular weight of 20,000 to 1,000,000 g / mol.

[0015]

[0010] 3-hydroxy propionate, as a monomer of the poly(3-hydroxy propionate), may be produced by fermentation or chemical synthesis, and may have a biodegradability higher than that of cellulose.

[0016]

[0011] 3-hydroxy propionate, as a monomer of the poly(3-hydroxy propionate), may be biocompatible and may exhibit no biotoxicity.

[0017]

[0012] The film of this aspect may have a voltage of 2 V or less.

[0018]

[0013] The film of this aspect may have a resistance ranging from I xlO11to l x IO12ohm / sq.

[0019]

[0014] In the film of this aspect, the biodegradability in natural soil, measured after 90 days, may range from 34% to 40%.

[0020]

[0015] According to another aspect, there is provided a method for manufacturing a non-toxic biodegradable antistatic film, including: a first process of introducing poly(3- hydroxy propionate) produced from a plant-derived raw material by a bioprocess and an antistatic agent into a solvent to prepare a mixture; a second process of heating and blending the mixture; and a third process of applying the heated mixture to a substrate to produce a film.

[0021]

[0016] The heating in the second process may be performed at 80 to 170 °C for 30 to 120 minutes.

[0022]

[0017] According to the present invention, a biodegradable antistatic film not harmful to a human body (that is, non-toxic) using poly 3-hydroxy propionate can be provided.

[0023]

[0018] Further, it is possible to provide a method for manufacturing a non-toxic biodegradable antistatic film using poly 3-hydroxy propionate.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025]

[0019] FIG. 1 is a process schematic diagram illustrating a method for manufacturing a non-toxic biodegradable antistatic film according to an aspect of the present invention.

[0026]

[0020] FIG. 2 is an image showing the result of measuring voltages for the antistatic films according to the examples and comparative example of the present invention.

[0027]

[0021] FIG. 3 is an image illustrating the measurement of surface resistances for the antistatic films according to the examples and comparative example of the present invention.

[0028]

[0022] FIG. 4 is an image showing the result of measuring surface resistances for the antistatic films according to the examples and comparative example of the present invention.

[0029]

[0023] FIGS. 5 A and 5B are images showing the result of visibly observing biodegradable property (natural soil) of the films according to the examples and comparative example of the present invention.

[0024] FIG. 6 is an image illustrating the numerical result of evaluating biodegradable property (natural soil) of the films according to the example and comparative example of the present invention.

[0030]

[0025] FIG. 7 is an image showing the result of evaluating biodegradable property (accumulation of evolved CO2 amount) of poly (3 -hydroxy propionate).

[0031]

[0026] FIG. 8 is a graph illustrating the result of evaluating biodegradable property (accumulation of evolved CO2 amount) for ethyl (3-hydroxy propionate), 3-hydroxy propionate and microcrystalline cellulose.

[0032]

[0027] FIG. 9 is an image showing the bio-toxicity test result of 3-hydroxy propionate.

[0033] DETAILED DESCRIPTION

[0034]

[0028] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment of the present invention may be modified in other different forms, and the scope of the present invention should not be limited to the embodiments described below. The embodiment of the present invention is provided for more completely explaining the present invention to those having ordinary knowledge in the art. Accordingly, shapes and sizes of elements in the drawings may be exaggerated for more obvious explanation, and the elements indicated the same numerals or symbols are considered as the same elements. In the present invention, the expression of ‘first’ or ‘second’ is used not to mean the order or importance but to simply distinguish individual components.

[0035]

[0029] The present invention relates to a non-toxic biodegradable antistatic film, and a method for manufacturing the non-toxic biodegradable antistatic film.

[0030] FIG. 1 illustrates a process schematic diagram of a method for manufacturing the non-toxic biodegradable antistatic film according to an aspect of the present invention. FIG. 2 is an image showing the result of measuring voltages for the antistatic films according to the example and comparative examples of the present invention. FIG. 3 is an image showing the measurement of surface resistances for the antistatic films according to the examples and comparative example of the present invention. FIG. 4 is an image showing the result of measuring surface resistances for the antistatic films according to the examples and comparative example of the present invention. FIGS. 5 A and 5B are images showing the result of visibly observing biodegradable property (natural soil) of the films according to the examples and comparative example of the present invention. FIG. 6 illustrates the numerical result of evaluating biodegradable property7(natural soil) of the films according to the examples and comparative example of the present invention. FIG. 7 illustrates the result of evaluating biodegradable property' (accumulation of evolved CO2 amount) of poly(3-hydroxy propionate). FIG. 8 is a graph illustrating the result of evaluating biodegradable property7(accumulation of evolved CO2 amount) for ethyl (3- hydroxy propionate), 3-hydroxy propionate and microcrystalline cellulose. FIG. 9 illustrates the bio-toxicity7test result of 3-hydroxy propionate.

[0036]

[0031] An aspect of the present invention may provide a non-toxic antistatic film, which includes poly (3 -hydroxy propionate) produced from plant-derived raw materials by a bioprocess, as well as an antistatic agent. The antistatic film according to the present aspect is excellent in biodegradation, eco-friendly, and not toxic to cells of the human body, therefore, may be harmless to humans.

[0037]

[0032] A biodegradable material may be a substance that is degraded by itself due to environmental factors such as moisture, microorganisms, temperature, etc. and is absorbed into the human body, discharged out of the human body, or absorbed in the form of organic materials into the ground. The term of ‘biodegradable’ means matters defined based on ISO 17556 (Plastics - Determination of the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved).

[0038]

[0033] Among the biodegradable materials, 3-hydroxy propionate having 3 carbons and 2 different functional groups and a derivative compound thereof, for example, ethyl 3-hydroxy propionate have non-toxicity and excellent biodegradable property. Further, poly(3-hydroxy propionate) formed through polymerization of 3-hydroxy propionates has excellent biodegradability and thus can be applicable to various fields including, medical supplies, daily supplies and industrial products, etc.

[0039]

[0034] Poly (3 -hydroxy propionate) may be one produced from plant-derived raw materials by a bioprocess. Further, poly(3-hydroxy propionate) derived from biomass may be more excellent in biodegradable property.

[0040]

[0035] An active ingredient in the present invention, that is. 3-hydroxy propionate (3- HP) may be obtained by a fermentation process using glycerol as the raw material. Inside a bioreactor including a minimum medium, 3-hydroxy propionate was produced through aldehydation and carboxylation using Pseudomonas denitrificans strains. Pseudomonas denitrificans strain is a strain to produce aldehydation enzyme and carboxylation enzyme. When introducing glycerol, the glycerol may generate 3- hydroxypropion aldehyde (3-HPA) intermediate product due to the enzy me to be produced by the strain, followed by finally producing 3-hydroxy propionate. The minimum medium is a composition including 0.5 g / L of NaCl, 1 g / L of NHrCl, 0.5 g / L of yeast extract, 6 g / L of NazHPCh, 3 g / L of KH2PO4, and 2 g / L of gluconate.

[0041]

[0036] Further. 3-hydroxy propionate (3-HP) can be synthesized by any chemical method using carbon monoxide generated from natural energy raw materials. Specifically, a P-lactone compound, that is, P-propio lactone is formed as an intermediate material by catalyzing carbon monoxide and ethylene oxide as an epoxide compound, and then, the formed intermediate material may be subjected to an open-ring reaction to thus produce a biodegradable material, that is, 3-hydroxy propionate (3-HP).

[0042]

[0037] Poly(3-hydroxy propionate) may have an average molecular weight of 20,000 to 1,000,000 g / mol. In this regard, polymer copolymer having low molecular weight may be mixed therein. The average molecular weight capable of being produced based on a bioprocess may range from 400,000 to 1,000,000 g / mol. The higher the molecular weight, the wider the applicable field. However, the molecular weight over 1,000,000 g / mol may entail a difficulty in production itself.

[0043]

[0038] Poly (3 -hydroxy propionate) has excellent biodegradability7. Referring to FIG.

[0044] 7, according to the result of measuring accumulation of evolved CO2 amount carried out for poly(3-hydroxy propionate), polylactic acid (PLA) and cellulose, PLA (polylactic acid) showed very little CO2 (carbon dioxide) generation and thus demonstrated no biodegradation. On the other hand, for poly(3-hydroxy propionate), it could be confirmed that a CO2 generation amount is remarkably increased.

[0045]

[0039] A monomer of poly(3-hydroxy propionate), that is, 3-hydroxy propionate is also excellent in biodegradation. Poly (3 -hydroxy propionate) is biodegraded and monomerized into 3-hydroxy propionate, then, finally and completely degraded into carbon dioxide (CO2) and water (H2O), so that the biodegradable property of 3-hydroxy propionate may have important meanings.

[0046]

[0040] Specifically, 3-hydroxy propionate as the monomer of poly (3-hydroxy propionate) may have the biodegradability7higher than cellulose. According to the result of measuring the accumulation of evolved CO2 amount of 3-hydroxy propionate in FIG.

[0047] 8, it can be confirmed that the biodegradability is sequentially decreased in the order of ethyl 3-hydroxy propionate. 3-hydroxy propionate and cellulose. In general, although the cellulose has high biodegradability in the natural soil, the above materials show more excellent biodegradability. In the case of 3-hydroxy propionate, it is completely degraded after about 15 days and CO2 generation amount thereof is not further increased. On the other hand, it can be confirmed that cellulose is still under degradation and continuously generates CO2.

[0048]

[0041] When the biodegradability is evaluated using the accumulation of evolved CO2 amount, the biodegradability may be compared with reference to a time point at which a slope of CO2 generation amount reaches a horizontal position. That is, in the case of monomer (ethyl 3-hydroxy propionate, 3-hydroxy propionate and cellulose), the biodegradability may be relatively compared with reference to the time point at which all molecules are completely degraded into CO2 (at the time when the CO2 generation amount is not further increased).

[0049]

[0042] The method of measuring accumulation of evolved CO2 amount to evaluate a biodegradability may be implemented as follows. That is. using microcrystalline cellulose as a control group, an amount of CO2 generated from bacteria in soil is measured so that a degree of biodegradation can be evaluated. The CO2 generation amount maybe measured based on IR sensor. A flask containing soil is placed in a thermostat under dark room conditions, and air may be supplied thereto through an inlet using a pump at a constant flow rate till the completion of biodegradation experiment. A CO2 concentration may be measured by connecting am outlet to a CO2 meter and thus the accumulation of evolved CO2 amount may be measured, thereby calculating the biodegradability.

[0050]

[0043] As a control group, microcrystalline cellulose may be used to confirm the suitability of soil for biodegradation test as a biodegradable sample and the validity of biodegradation test. At a time point of 45 days after initiating biodegradation, if the biodegradability of microcrystalline cellulose is over 60%, it is considered as the soil suitable for ASTM, ISO basic biodegradation experiments, and it may demonstrate that the biodegradation experiment now proceeded is valid. The biodegradation experiment is done under the environment condition that is imitative of actually real soil and may be performed at room temperature of 23 °C as a reaction temperature. Since CO2 and methane are simultaneously generated at the biodegradation under anaerobic conditions, it is possible to maintain aerobic conditions so as to generate CO2 only. From the initial degradation experiment till the completion thereof, air can be supplied to each flask containing soil at a flow rate of 200 ml / min. Then, while monitoring the CO2 generation amount, the biodegradability measurement experiment may be terminated when the biodegradability of microcrystalline cellulose is 60% or more and no more significant CO2 generation in real time in the flask containing a test sample is observed compared to the blank. The calculation of biodegradability is done as follows: that is, after dividing the CO2 generation amount measured in the experiment of the test sample by a theoretical CO2 generation amount, the resulting value may be evaluated by %.

[0051]

[0044] 3-hydroxy propionate as a monomer of poly(3-hydroxy propionate) may not have toxicity to a living body. While poly(3-hydroxy propionate) is degraded, firstly, it may be changed into 3-hydroxy propionate and the monomer may contact the body. Therefore, it may be significantly meaningful to evaluate the toxicity of the monomer. FIG. 9 illustrates the toxicity test result of 3-hydroxy propionate to the body. From the result, it could be confirmed that the monomer does not toxicity to the body.

[0052]

[0045] As the test for toxicity to the body (‘biotoxicity test’), a test for animal (rabbit) was implemented to confirm the result as follows. Using 3-HP crude solution at a concentration of 9.3%(w / v) (93 g / L), a final solution having a 3-HP concentration of 4.65 g / L may be prepared and used. With the rabbits, initial test and confirmatory test were conducted to assess stability of 3-HP material. The initial test was performed by continuously applying a test sample in the form of patch to No. 3 animal and evaluating the result. First patch was removed after 3 minutes, second patch was removed after 1 hour, and third patch was removed after 4 hours. Unapplied site and control site were set in the same animal. In the initial test, corrosion (that is, eschar formation) was not found and thus a confirmatory test proceeded. One patch was attached to each of individual animals and, after 4 hours, removed. Alternatively, a gauze patch (without the sample) was attached to the control site and, after 4 hours, removed.

[0053]

[0046] In the initial test, no erythema (red spots), edema and eschar formation were found after removal of the patch. Even after 24 hours, 48 hours and 72 hours, it was confirmed that there is no abnormal condition as a result of observing a dermal response. Further, even with additional observation for 14 days, it was confirmed that there is nothing unusual about the skin.

[0054]

[0047] The monomer of poly(3-hydroxy propionate), that is, 3-hydroxy propionate may have high biocompatibility. Specifically, poly(3-hydroxy propionate) shows high biodegradability of about 34% for 90 days and, at the same time, 3-hydroxy propionate as the monomer thereof also shows very high biocompatibility because it has high full biodegradation into water and CO2 and thus does not exist as a micro- or nano-plastic form in the human body. As a consequence, it is possible to minimize side effects such as environmental hormones or the like.

[0055]

[0048] The antistatic film of the present aspect may include 33 to 94 wt% of poly(3- hydroxy propionate), and 6 to 67 wt% of an antistatic agent. When a content of the antistatic agent is in the above range, the film may have antistatic effects (with surface resistance of about 1 x 1010to 1 x 1012ohm / sq) while maintaining biodegradability. If the content of the antistatic agent exceeds the upper limit, it may cause a problem of poor processing ability, for example, no formation of film.

[0049] As the antistatic agent, nonionic low molecular weight antistatic agents such as ethoxylated alkylamines, fatty acid esters, glycerides alkylamines, polyethyleneglycol esters, etc., or polymeric antistatic agents such as polypyrrole, polyfuran, polythiophene, polyselenophene, PANI. etc. may be used. In particular, nonionic surfactants may be used because they absorb moisture in atmosphere even in a small amount to reduce surface resistance, thereby preventing generation of static electricity.

[0056]

[0050] The film of the present aspect may have voltage of 2 V or less. The voltage may be measured using CAS portable electrostatic meter (ARS-H002ZA). After rubbing the antistatic film 3 times, the voltage may be measured using the electrostatic meter in an ionic balance measuring mode. The film with high resistance includes accumulated electrons to show a high voltage, whereas the film with low resistance does not accumulate electrons and may have a low voltage and thus can be utilized as an antistatic film.

[0057]

[0051] The film of the present aspect may have surface resistance of 1 x 1011to 1 x 1012ohm / sq.

[0058]

[0052] The surface of the film may be divided into a conductive region when the surface resistance value (ohm / sq) is 103to 106, a static dissipative region when the surface resistance value is 106to IO10, an antistatic region when the surface resistance value is IO10to 1013, and an insulative region when the surface resistance value is 1013to IO20(see FIG. 4).

[0059]

[0053] The film of the present aspect may have a surface resistance value of 1 x 1011to l * 1012ohm / sq. This surface resistance value corresponds to the antistatic region. Therefore, it can be confirmed that the film of the present invention has antistatic function. Surface resistance may be measured using a surface resistance device (ESD SURPA-385).

[0054] The film of the present aspect may have excellent biodegradability in natural soil. The biodegradability may be due to a poly(3-hydroxy propionate) component. After placing the poly (3 -hydroxy propionate) film on the natural soil, a degree of biodegradation could be visibly observed over time. Test environments preferably include a temperature of 25 °C and a humidity of 40 to 60%. The poly(3-hydroxy propionate) (P3PH) film may exhibit faster biodegradability than other comparative samples (PLA, PHS, PBAT) (see FIGS. 5A and 5B).

[0060]

[0055] The biodegradability of poly(3-hydroxy propionate) (P3PH) to the natural soil may range from 34 to 40%. From the result of quantitative measurement of the biodegradability of P3PH to the natural soil, it could be confirmed that the biodegradability value measured after 90 days is 36.4% (see FIG. 6). In the case of PLA (polylactic acid), which is currently the popularly and mostly used biodegradable plastic, the biodegradability is about 15% with reference to ISO 17556 test conditions (Ref: Waste Manag. 2021, 134, 67-77). As compared to PLA, it could be confirmed that P3PH exhibits noticeably higher biodegradability. In particular, FIG. 6 illustrates that PLA has the biodegradability of 9%.

[0061]

[0056] Quantitative evaluation of the biodegradability' of poly(3-hydroxy propionate) (P3PH) to natural soil may be calculated as follows. That is, in the case of a polymer, that is, poly(3-hydroxy propionate), a value obtained by subtracting the mass after 90 days from the initial mass is converted into wt% with reference to 100% of initial mass, thereby calculating the biodegradability as shown in the following equation.

[0062]

[0057] x = 100 x (a - b) / a

[0063]

[0058] Wherein, x is the biodegradability, a is the initial mass, and b is the mass after 90 days.

[0064]

[0059] FIG. 7 illustrates the test result of evaluating biodegradable property by measuring the accumulation of evolved CO2 amount in regard to the poly(3-hydroxy propionate) (poly(3-HP)) film. Herein, microcrystalline cellulose is a standard material while poly(lactic acid) (PLA) is a biodegradable polymer currently and mostly used in the art. It can be confirmed that poly(3-HP) has remarkably excellent biodegradability than PLA.

[0065]

[0060] Another aspect of the present invention may provide a method for manufacturing a non-toxic biodegradable antistatic film, which includes: a first process of introducing poly(3-hydroxy propionate) and an antistatic agent into a solvent to prepare a mixture; a second process of heating and blending the mixture; and a third process of applying the heated mixture to a substrate to produce a film. The produced antistatic film is excellent in biodegradation and eco-friendly, is not toxic to cells of the human body, and thus, has an advantage of being harmless to the human body.

[0066]

[0061] Firstly, poly(3-hydroxy propionate) and an antistatic agent may be introduced into a solvent to thus prepare a mixture (first process).

[0067]

[0062] Poly(3-hydroxy propionate) may be produced from a plant-derived raw material by a bioprocess. Poly(3-hydroxy propionate) derived from biomass has more excellent biodegradation property.

[0068]

[0063] 3-hydroxy propionate (3-HP) as an active ingredient of the present invention was obtained by a fermentation process using glycerol as a raw material. Inside a bioreactor including a minimum medium, 3-hydroxy propionate was produced through aldehydation and carboxylation using Pseudomonas denitrificans strains. Pseudomonas denitrificans strain is a strain to produce aldehydation enzy me and carboxylation enzy me. When introducing glycerol, the glycerol may generate 3-hydroxypropion aldehyde (3- HPA) intermediate product due to the enzyme to be produced by the strain, followed by finally producing 3-hydroxy propionate. The minimum medium is a composition including 0.5 g / L of NaCl, 1 g / L of NH4CI, 0.5 g / L of yeast extract, 6 g / L of Na2HPC>4, 3 g / L of KH2PO4, and 2 g / L of gluconate.

[0069]

[0064] Further, 3-hydroxy propionate (3-HP) can be synthesized by any chemical method using carbon monoxide generated from natural energy raw materials. Specifically, a P-lactone compound, that is, P-propio lactone is formed as an intermediate material by catalyzing carbon monoxide and ethylene oxide as an epoxide compound, and then, the formed intermediate material may be subjected to an open-ring reaction to thus produce a biodegradable material, that is, 3-hydroxy propionate (3-HP).

[0070]

[0065] Poly (3-hydroxy propionate) may have an average molecular weight of 20,000 to 1,000,000 g / mol. In this regard, polymer copolymer having a low molecular weight may be mixed therein. The average molecular weight capable of being produced based on a bioprocess may range from 400,000 to 1,000,000 g / mol. The higher the molecular weight, the wider the applicable field. However, the molecular weight over 1,000,000 g / mol may entail a difficulty in production itself.

[0071]

[0066] In the present aspect, poly(3-hydroxy propionate) has excellent biodegradability. Referring to FIG. 7, according to the result of measuring accumulation of evolved CO2 amount carried for poly(3-hydroxy propionate), polylactic acid (PLA) and cellulose, PLA (polylactic acid) showed very little CO2 (carbon dioxide) generation and thus demonstrated no biodegradation. On the other hand, for poly (3 -hydroxy propionate), it could be confirmed that CO2 generation amount is remarkably increased.

[0072]

[0067] A monomer of poly(3-hydroxy propionate), that is, 3-hydroxy propionate is also excellent in biodegradation. Poly (3 -hydroxy propionate) is biodegraded and monomerized into 3-hydroxy propionate, then, finally and completely degraded into carbon dioxide (CO2) and water (H2O), so that the biodegradable property of 3-hydroxy propionate may have important meanings.

[0068] 3-hydroxy propionate as the monomer of poly (3 -hydroxy propionate) may have the biodegradability higher than cellulose. According to the result of measuring the accumulation of evolved CO2 amount of 3-hydroxy propionate in FIG. 8, it can be confirmed that the biodegradability is sequentially decreased in the order of ethyl 3- hydroxy propionate, 3-hydroxy propionate and cellulose. In general, although the cellulose has high biodegradability in the natural soil, the above materials show more excellent biodegradability7. In the case of 3-hydroxy propionate, it is completely degraded after about 15 days and the CO2 generation amount thereof is not further increased. On the other hand, it can be confirmed that cellulose is still under degradation and continuously generates CO2.

[0073]

[0069] When the biodegradability7is evaluated using the accumulation of evolved CO2 amount, the biodegradability may be compared with reference to a time point at which a slope of CO2 generation amount reaches a horizontal position. That is, in the case of monomer (ethyl 3-hydroxy propionate, 3-hydroxy propionate and cellulose), the biodegradability may be relatively compared with reference to the time point at which all molecules are completely degraded into CO2 (at the time when CO2 generation amount is not further increased).

[0074]

[0070] The method of measuring accumulation of evolved CO2 amount to evaluate a biodegradability may be implemented as follows. That is, using microcrystalline cellulose as a control group, an amount of CO2 generated from bacteria in soil is measured so that a degree of biodegradation can be evaluated. The CO2 generation amount may be measured based on IR sensor. A flask containing soil is placed in a thermostat under dark room conditions, and air may be supplied thereto through an inlet using a pump at a constant flow rate till the completion of biodegradation experiment. CO2 concentration may be measured by connecting an outlet to a CO2 meter and thus the accumulation of evolved CO2 amount may be measured, thereby calculating the biodegradability.

[0071] As a control group, microcrystalline cellulose may be used to confirm the suitability of soil for biodegradation test as a biodegradable sample and the validity of biodegradation test. At a time point of 45 days after initiating biodegradation, if the biodegradability of microcrystalline cellulose is over 60%, it is considered as the soil suitable for ASTM, ISO basic biodegradation experiments and may demonstrate that the biodegradation experiment now proceeded is valid. The biodegradation experiment is done under the environment condition that is imitative of actually real soil and may be performed at room temperature of 23 °C as a reaction temperature. Since CO2 and methane are simultaneously generated at the biodegradation under anaerobic conditions, it is possible to maintain aerobic conditions so as to generate CO2 only. From the initial degradation experiment till the completion thereof, air can be supplied to each flask containing soil at a flow rate of 200 ml / min. Then, while monitoring the CO2 generation amount, the biodegradability measurement experiment may be terminated when the biodegradability of microcrystalline cellulose is 60% or more and no more significant CO2 generation in real time in the flask containing a test sample is observed compared to the blank. The calculation of biodegradability is done as follows: that is, after dividing the CO2 generation amount measured in the experiment of the test sample by a theoretical CO2 generation amount, the resulting value may be evaluated by %.

[0075]

[0072] 3-hydroxy propionate as a monomer of poly(3-hydroxy propionate) may not have toxicity to a living body. While poly(3-hydroxy propionate) is degraded, firstly, it may be changed into 3-hydroxy propionate and the monomer may contact the body. Therefore, it may be significantly meaningful to evaluate the toxicity of the monomer.

[0076]

[0073] FIG. 9 illustrated the toxicity test result of 3-hydroxy propionate to a living body. According to this result, it could be confirmed that 3-hydroxy propionate is non-toxic to

[0074] As the test for toxicity to the body (‘biotoxicity test’), a test for animal (rabbit) was implemented to confirm the result as follows. Using 3-HP crude solution at a concentration of 9.3%(w / v) (93 g / L), a final solution having a 3-HP concentration of 4.65 g / L may be prepared and used. With the rabbits, initial test and confirmatory test were conducted to assess stability of 3-HP material. The initial test was performed by continuously applying a test sample in the form of patch to No. 3 animal and evaluating the result. First patch was removed after 3 minutes, second patch was removed after 1 hour, and third patch was removed after 4 hours. Unapplied site and control site were set in the same animal. Since no eschar was observed in the initial test, a confirmatory test proceeded. One patch was attached to individual animals and, after 4 hours, removed. Alternatively, a gauze patch (without the sample) was attached to the control site and, after 4 hours, removed.

[0077]

[0075] In the initial test, no erythema (red spots), edema and eschar formation were found after removal of the patch. Even after 24 hours, 48 hours and 72 hours, it was confirmed that there is no abnormal condition as a result of observing a dermal response. Further, even with additional observation for 14 days, it was confirmed that there is nothing unusual about the skin.

[0078]

[0076] The monomer of poly(3-hydroxy propionate), that is, 3-hydroxy propionate may have high biocompatibility. Specifically, poly(3-hydroxy propionate) shows high biodegradability of about 34% for 90 days and, at the same time, 3-hydroxy propionate as the monomer thereof also shows very high biocompatibility because it has high full biodegradation into water and CO2 and thus does not exist as a micro- or nano-plastic form in the human body. As a consequence, it is possible to minimize side effects such as environmental hormones or the like.

[0079]

[0077] The solvent may be a chemical substance capable of dissolving poly(3-hydroxy propionate). More particularly, it may be 100% pure chloroform because chloroform has a high solubility of 8% to poly(3-hydroxy propionate), however, is not particularly limited thereto. The solvent used herein may include dimethyl carbonated (DMC). A thickness, physical properties and / or a shape of the manufactured film may be controlled by adjusting a concentration of poly(3-hydroxy propionate). The concentration of poly(3-hydroxy propionate) is preferably 8% in the mixture.

[0080]

[0078] The mixture of the present aspect may include 1.0 to 8.0 wt% of poly(3-hydroxy propionate), 0.5 to 2.0 wt% of an antistatic agent, and the remaining solvent (in the range of 90 to 98.5 wt%).

[0081]

[0079] When a content of the antistatic agent is in the above range, antistatic effects (with surface resistance of about I x lO10to I x lO12ohm / sq) may be attained while maintaining the biodegradability. If the content of the antistatic agent exceeds 2 wt%, it may cause a problem of poor processing ability, for example, no formation of film.

[0082]

[0080] As the antistatic agent, nonionic low molecular weight antistatic agents such as ethoxylated alkylamines, fatty acid esters, glycerides alkylamines, polyethyleneglycol esters, etc., or polymeric antistatic agents such as poly pyrrole, polyfuran, poly thiophene, polyselenophene, PANI, etc. may be used. In particular, nonionic surfactants may be used because they absorb moisture in atmosphere even in a small amount to reduce surface resistance, thereby preventing generation of static electricity.

[0083]

[0081] Next, the mixture may be heated and blended (second process).

[0084]

[0082] The heating may be continued at 80 to 170 °C for 30 to 120 minutes. Since poly(3-hydroxy propionate) has a melting point of 80 °C, it needs to be dissolved at a higher temperature than the melting point. On the other hand, if heating at a temperature higher than 170 °C or for 2 hours or more, poly(3-hydroxy propionate) may be degraded to thus reduce a molecular weight thereof. Preferably, heating may be done at 150 °C for 60 minutes.

[0083] Following this, the heated mixture may be applied to a substrate, followed by natural drying to produce a film (third process). As the substrate, a glass plate may be used, but is not limited thereto. A thickness or shape of the film may be controlled by adjusting the concentration of the mixture.

[0085]

[0084] Hereinafter, the present invention will be described in detail by w ay of examples. However, the present invention is not limited to the examples.

[0086]

[0085] <Example 1>

[0087]

[0086] Poly (3 -hydroxy propionate) (P(3-HP)) and an antistatic agent (JISTAT 300A) were introduced into 100% chloroform to prepare a mixture. As P(3-HP), a compound produced by a biological method using a plant-derived raw material was used. The mixture was prepared such that a concentration of P(3-HP) is 8 wt%, chloroform is 91.5 wt% and a concentration of the antistatic agent is 0.5 wt%. The mixture was blended while heating at 150 °C for 60 minutes. The blended mixture was applied to a glass plate to thus produce a film.

[0088]

[0087] <Example 2>

[0089]

[0088] A film was produced by the same procedure as described in Example 1. except that the concentration of the antistatic agent was 1 wt%.

[0090]

[0089] <Example 3>

[0091]

[0090] A film as produced by the same procedure as described in Example 1, except that the concentration of the antistatic agent was 2 wt%.

[0091] Comparative Example 1 >

[0092]

[0092] A film was produced by the same procedure as described in Example 1, except that the concentration of the antistatic agent was 0 wt% (that is, without addition of the antistatic agent).

[0093]

[0093] <Evaluation>

[0094]

[0094] 1, Antistatic property

[0095]

[0095] For the films produced according to the examples and comparative example, each film was subjected to assessment of the static electricity prevention property (antistatic property). The results of the assessment were shown in FIGS. 2 to 4.

[0096]

[0096] Referring to FIG. 2, the voltage value was measured as 2 for Examples 1 to 3, and 11 for Comparative Example 1. Referring to FIG. 3, the resistance value was measured as 1011to 1012for Examples 1 to 3, and more than 1013for Comparative Example 1.

[0097]

[0097] When the resistance value is in the range of 1011to 1012, it is classified into a substance having static electricity preventive (antistatic) property. According to the measured results, it could be confirmed that the films in Examples 1 to 3 have antistatic property, while the film in Comparative Example 1 has insulative property.

[0098]

[0098] 2. Biodegradable property of polv(3-hydroxy propionate)

[0099]

[0099] The biodegradable property of the antistatic film according to the present invention is determined by a biodegradable material, that is, poly(3-hydroxy propionate). Therefore, the film produced using poly(3-hydroxy propionate) was subjected to assessment of biodegradable property. A test for biodegradation to natural soil and a test of measuring accumulation of evolved CO2 amount were conducted.

[0100] In the test for biodegradation to natural soil, PLA, PBS and PBAT were used as the control groups (Comparative Example). Further, in the test of measuring accumulation of evolved CO2 amount, PLA and cellulose were used as the control groups (Comparative Example).

[0100]

[0101] The result of the test for biodegradation to natural soil w as illustrated in FIGS.

[0101] 5 and 6, while the result of the test for accumulation of evolved CO2 amount was illustrated in FIG. 7.

[0102]

[0102] FIGS. 5 A and 5B illustrates images taken at a time point of passing 90 days after leaving the experimental group and control group on the natural soil. Referring to FIGS. 5A and 5B, the experimental group showed degradation having proceeded on most part thereof. On the other hand, it could be confirmed that, for the control group 1, degradation proceeded on a part thereof, while the control groups 2 and 3 the control group 1 showed no progress of degradation.

[0103]

[0103] FIG. 6 demonstrates the result of FIGS. 5A and 5B converted into a numerical value. Specifically, the value obtained by subtracting the mass after 90 days from the initial mass was converted into wt% with reference to 100% initial mass as shown in the following equation.

[0104]

[0104] x = 100 x (a - b) / a

[0105]

[0105] Wherein, x is the biodegradability, a is the initial mass, and b is the mass after 90 days.

[0106]

[0106] Referring to FIG. 6, it could be confirmed from the result of quantitively measuring the biodegradability' of poly (3 -hydroxy propionate) (P3PH) to natural soil that the biodegradability value measured after 90 days is 36.4%.

[0107]

[0107] FIG. 7 illustrates the test result of evaluating biodegradable property by measuring accumulation of evolved CO2 amount for the poly(3-hydroxy propionate) film (Respirometer 25 °C, 200 ml / min). In this case, microcrystalline cellulose is a standard material while PLA (poly(lactic acid)) is a biodegradable polymer currently and mostly used in the art. It could be confirmed that poly(3-hydroxy propionate) has remarkably more excellent biodegradability than PLA.

[0108]

[0108] 3-3 Biodegradable property of 3-hvdroxy propionate

[0109]

[0109] Since poly(3-hydroxy propionate) is biodegraded and monomerized into 3- hydroxy propionate, and then, finally and completely degraded into carbon dioxide (CO2) and water (H2O), the biodegradable property of 3-hydroxy propionate has important meanings. For the film produced using 3-hydroxy propionate, the test of measuring accumulation of evolved CO2 amount was performed.

[0110]

[0110] FIG. 8 illustrates the result of evaluating biodegradable property by measuring the accumulation of evolved CO2 amount over time for 3-hydroxy propionate. Referring to FIG. 8, it can be confirmed that the biodegradability is sequentially decreased in the order of ethyl 3-hydroxy propionate. 3-hydroxy propionate and cellulose. In general, although the cellulose has high biodegradability in the natural soil, it could be confirmed that the above materials have more excellent biodegradability'. In the case of 3-hydroxy propionate, it is completely degraded after about 15 days and a CO2 generation amount thereof is not further increased. On the other hand, it can be confirmed that cellulose is still under degradation and continuously generates CO2.

[0111]

[0111] When the biodegradability’ is evaluated using the accumulation of evolved CO2 amount, the biodegradability may be compared with reference to a time point at which a slope of CO2 generation amount reaches a horizontal position. That is, in the case of monomer (ethyl 3-hydroxy propionate, 3-hydroxy propionate and cellulose), the biodegradability may be relatively compared with reference to the time point at which all molecules are completely degraded into CO2 (at the time when the CO2 generation amount is not further increased).

[0112] 4, Assessment of biotoxicitv of 3-hydroxy propionate

[0112]

[0113] It is important whether a monomer generated by biodegradation of poly(3- hydroxy propionate), that is, 3-hydroxy propionate has cytotoxicity or not. Polyhydroxy alkanoate (PHA) is a material that is formed and used as an energy storage in a cell and is known as a material having no cytotoxicity. Further, plastics such as polyethylene (PE) and polypropylene (PP) are not toxic in a polymer state but may express toxicity to cells in the form of environmental hormones when they are degraded into micro-plastic or nanoplastic substances. Therefore, it is important whether a material generated after degradation of polymer has toxicity or not.

[0113]

[0114] 3-hydroxy propionate was subjected to a biotoxicity test. The biotoxicity test was implemented for animals (rabbits) by the following method. The result of the biotoxicity is shown in FIG. 9.

[0114]

[0115] Using 3-hydroxy propionate (3-HP) crude solution at a concentration of 9.3%(w / v) (93 g / L), a final solution having a 3-HP concentration of 4.65 g / L was prepared and used. With the rabbits, initial test and confirmatory test were conducted to assess stability of 3-HP material. The initial test was performed by continuously applying a test sample in the form of patch to No. 3 animal and evaluating the result. First patch was removed after 3 minutes, second patch was removed after 1 hour, and third patch was removed after 4 hours. Unapplied site and control site were set in the same animal. In the initial test, eschar formation was not found and thus a confirmatory' test proceeded. One patch was attached to each of individual animals and, after 4 hours, removed. Alternatively, a gauze patch (without the sample) was attached to the control site and, after 4 hours, removed.

[0115]

[0116] In the initial test, no erythema (red spots), edema and eschar formation were found after removal of the patch. Even after 24 hours, 48 hours and 72 hours, it was confirmed that there is no abnormal condition as a result of observing a dermal response. Further, even with additional observation for 14 days, it was confirmed that there is nothing unusual about the skin.

[0116]

[0117] As described above, as a result of bio-toxicity (or cytotoxicity) test to animal (rabbit), it could be confirmed that 3-hydroxy propionate is non-toxic to a living body.

[0117]

[0118] Terms used in the present invention are provided for explaining specific embodiments but not intended to limit the present invention. As used herein, a singular expression is duly considered to include the meanings of plural form unless the context clearly clarifies otherwise. Further, it will be understood that the terms “include'’ or “have” specify the presence of stated features, integers, steps, operations, elements or a combination thereof in the specification, but do not preclude or exclude the same.

[0118]

[0119] The present invention is not limited by the aforementioned embodiments and accompanying drawings but is intended to be defined by the appended claims. Therefore. it should be understood that various substitutions, modifications and alterations may be possible by those having ordinary knowledge in the art without departing from the technical spirit of the present invention described in the claims, which are further included in the scope of the present invention.

Claims

WHAT IS CLAIMED IS:

1. A non-toxic biodegradable antistatic film, comprising: poly(3-hydroxy propionate) produced from a plant-derived raw material by a bioprocess: and an antistatic agent.

2. The antistatic film according to claim 1, wherein the poly (3 -hydroxy propionate) has a molecular weight of 20.000 to 1,000,000 g / mol.

3. The antistatic film according to claim 1, wherein 3-hydroxy propionate, as a monomer of the poly(3-hydroxy propionate), is produced by a fermentation synthesis or a chemical synthesis, and has a biodegradability higher than that of cellulose.

4. The antistatic film according to claim 1, wherein 3-hydroxy propionate, as a monomer of the poly(3-hydroxy propionate), is biocompatible and exhibits no biotoxicity.

5. The antistatic film according to claim 1, wherein the antistatic film has a voltage of 2 V or less.

6. The antistatic film according to claim 1, wherein the antistatic film has a resistance ranging from 1 x1011 to 1x 1012 ohm / sq.

7. The antistatic film according to claim 1, wherein the antistatic film has a biodegradability in natural soil, measured after 90 days, ranging from 34% to 40%.

8. A method for manufacturing a non-toxic biodegradable antistatic film, the method comprising: a first process of introducing poly(3-hydroxy propionate) produced from a plant- derived raw material by a bioprocess and an antistatic agent into a solvent to prepare a mixture; a second process of heating and blending the mixture; and a third process of applying the heated and blended mixture to a substrate to produce a film.

9. The method according to claim 8, wherein the heating in the second process is performed at 80 to 170 °C for 30 to 120 minutes.

Images