KR102191338B1 - Eco-friendly composition improved in biodegradability and plasticity and the preparation method thereof - Google Patents

Abstract

The present invention relates to an eco-friendly composition having improved biodegradability and processability, such as heat resistance, hydrolysis resistance and tensile strength, and capable of biodegradation in a natural state. Various products and containers for tables made of plastics can be substituted with those made by using the composition according to the present invention. In addition, the composition according to the present invention is degraded with ease by naturally occurring UV rays and microorganisms. Therefore, even when the products made by using the composition are allowed to stand in a natural state, after use, they are degraded naturally with no discharge of harmful substances to the air and soil, thereby preventing environmental pollution, one of the serious problems in the world. In addition, the composition according to the present invention shows higher strength and heat resistance, as compared to the eco-friendly resin compositions according to the related art, and thus can be applied to various industrial fields, including agriculture, fishery and food.

Description

Eco-friendly composition improved in biodegradability and plasticity and the preparation method thereof]

The present invention relates to an eco-friendly composition capable of biodegradation in a natural state with improved biodegradability and processability, and by using the composition provided in the present invention, various table products and containers manufactured using plastic can be replaced. In addition, the composition provided by the present invention is easily decomposed by ultraviolet rays and microorganisms existing in the natural state, so even if the product manufactured by using it is left in a natural state, it is naturally decomposed without emitting harmful substances to the air and soil. Therefore, it is possible to prevent environmental pollution, which is a recent global problem.

General synthetic resins are widely used in everyday life as a substitute for natural materials due to their excellent chemical resistance, durability, and various physical properties, but have a disadvantage in that they cannot be returned to nature when discarded after use. In particular, in the case of disposable packaging materials that are rapidly increasing in demand, separate collections are not performed smoothly and are often left unattended. In rural areas, separate collection items are often burned, causing many environmental problems.

In addition, conventional methods for disposing of the synthetic resin include burning waste, embedding it in the soil, and recovering and reusing the waste. However, the method of burning synthetic resin waste generates a large amount of toxic gas, resulting in secondary There is a problem that causes pollution, and the landfill method is also not decomposed and remains in the land, causing secondary pollution, and the method of recovering and reusing also has a problem in that a final waste is generated due to a low recovery rate.

In order to solve the above problems, studies using biodegradable resins that are degraded by microorganisms are actively being conducted.

The biodegradable resins include polyhydroxyatylate resins, polycaprolactones, synthetic aliphatic polyester resins, or resins in which a natural polymer material is mixed with a thermoplastic resin, which are biosynthesized and biodegradable in the body of microorganisms. Biodegradable resins are often mixed with photodegradable resins capable of natural decomposition by sunlight. The photodegradable resin contains oxidizing agents such as a resin copolymerized with ethylene and carbon monoxide, a resin copolymerized with ethylene and vinyl ketone, and a transition metal. And added resin. However, among the above resins, microbial-biosynthesized resins and synthetic aliphatic polyesters are excellent in degradability, but have a disadvantage in that the manufacturing price is high, and resins with natural polymers are inexpensive, but physical properties are not degraded and decomposed completely, and heat resistance. And there is a disadvantage in that the hydrolysis resistance is low and biodegradability and processability are deteriorated.

In order to solve the above problems, the present inventors have remarkably excellent heat resistance and hydrolysis resistance, but are excellent in biodegradability and processability, are inexpensive, and are easily degradable from biodegradable resins and natural products that can be easily decomposed by microorganisms present in the soil. Using a natural polymer material that can be collected, a composition that can replace conventional plastic products has been invented, and table products and containers manufactured using this composition are naturally produced by the ultraviolet rays of sunlight and microorganisms in the soil. Because it is decomposed, environmental pollution can be significantly reduced.

Korean Patent Publication No. 10-2015-0026368 Korean Patent Publication No. 10-2012-0024628

The present invention is to solve the above problems, and the eco-friendly composition and eco-friendly product using the same provided by the present invention are naturally decomposed by microorganisms present in the soil and sunlight when left unattended after use, and also heat resistance and The hydrolysis property is improved, so that the stability of the final product can be remarkably improved, the environmental pollution generated in the process of processing conventional plastic products can be reduced, and the strength and processability have been remarkably improved by adding inorganic substances.

Another object of the present invention is to provide a method for preparing an eco-friendly composition with improved biodegradability and processability.

In order to achieve the above object, the biodegradable eco-friendly composition provided in the present invention with improved biodegradability and processability is prepared by mixing pretreated starch starch, aluminum hydroxide powder, carbodiimide compound, and polylactic acid to produce a base material, It is made by mixing additives such as crystalline titanium dioxide, a coupling agent, a reinforcing agent, a heat stabilizer, and an antioxidant.

In addition, the method for preparing the biodegradable eco-friendly composition includes mixing the pretreated starch and aluminum hydroxide and stirring at high temperature, mixing and stirring a coupling agent and polylactic acid, crystalline titanium dioxide, a reinforcing agent, a heat stabilizer, an antioxidant, etc. Mixing and stirring, and treating the final product passed through the above step with ultraviolet rays.

The biodegradable eco-friendly composition with improved biodegradability and processability provided by the present invention is capable of being decomposed by sunlight and microorganisms in a natural state, unlike conventional synthetic plastic compositions, thus reducing environmental pollution generated in the process of treatment after using the product. In addition, it is possible to reduce all the problems of low strength and high hydrolyzability, which were problems of conventional biodegradable resins, and thus poor processability.

In addition, the composition provided by the present invention has the advantage of being able to supply large quantities of tableware and containers for a table at a low price due to a relatively high content of starch and low manufacturing cost.

In addition, the pretreated starch-containing composition of the present invention is mixed with various plastics, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, ABS resin, polycarbonate, polyamide, polyester, and other hydrophobic resins. By doing so, it is possible to impart hygroscopicity to the hydrophobic resin to impart antistatic properties.

Hereinafter, a biodegradable eco-friendly composition to be provided in the present invention will be described in detail.

The eco-friendly composition provided by the present invention is 30 to 50 parts by weight of aluminum hydroxide, 20 to 50 parts by weight of polylactic acid, 20 to 50 parts by weight of carbodiimide compound, 0.2 to 2 parts by weight of titanium dioxide crystals based on 100 parts by weight of pretreated starch starch Parts, 5 to 10 parts by weight of a coupling agent, 5 to 10 parts by weight of a reinforcing agent, 2 to 5 parts by weight of a heat stabilizer, and 0.2 to 2 parts by weight of an antioxidant.

The pretreated starch starch is preferably oxidized starch, carboxymethyl starch, hydroxyalkyl starch, esterified starch, starch acetate, starch phosphate, etc., obtained by pre-treating starch obtained from natural products, and also polyacrylic acid, polyvinyl acetate , Polyacrylamide, polyacrylonitrile, and the like are preferably grafted to use grafted starch.

The aluminum hydroxide used in the present invention uses a white powder, serves as a catalyst for promoting the bonding of starch starch, polylactic acid and carbodiimide compounds, and also functions to improve the mechanical strength of the final composition.

The carbodiimide compound used in the present invention is preferably a compound having at least one carbodiimide group in the molecule, including a polycarbodiimide compound. Specific examples of the carbodiimide compound include dicyclohexylcarbodiimide and di Isopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisope

Particularly preferred are lopilcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide and di-β-naphthylcarbodiimide.

The content of the carbodiimide compound is preferably 20 to 50 parts by weight based on 100 parts by weight of the pretreated starch starch, and when the content of the carbodiimide compound is less than 20 parts by weight, the biodegradability and processability of the composition is not significantly improved, and 50 When it exceeds a part by weight, the transparency of the composition may decrease.

The coupling agent may be a silane-based compound such as 3methylethoxysilane, methyltrimethoxysilane, or phenyltrimethoxysilane. The content of the coupling agent is preferably 5 to 10 parts by weight based on 100 parts by weight of the pretreated starch starch. When the coupling agent is less than 5 parts by weight, the hydrolysis resistance and thermal stability of the final product may be deteriorated, and when it exceeds 10 parts by weight, the processability of the composition may be lowered.

The titanium dioxide crystal is preferably an anatase-type crystal form, more preferably surface-treated with a silane compound, and γ-ammonia propyl methyl 2-ethoxy silane is used as a silane compound for surface treatment of the titanium dioxide. It is desirable to do. The titanium dioxide crystal has a function of sterilizing various kinds of bacteria, etc. when irradiated with sunlight, so when a food container is manufactured using this eco-friendly composition, the food container is contaminated by microorganisms harmful to the human body. Can be prevented.

It is preferable to use 0.2 to 2 parts by weight of the titanium dioxide crystal based on 100 parts by weight of the pretreated starch starch. If the titanium dioxide content is out of the above range, there is a concern that the processability of the final composition is deteriorated.

The reinforcing agent has an effect of improving the physical strength of the product when the product is manufactured using the eco-friendly composition, and inorganic substances such as talc may be used as the reinforcing agent. The talc is a material suitable for improving the heat resistance and strength of the eco-friendly composition because it is used as various types of fillers because of its strong absorbency and adhesion and good fire resistance.

The content of the reinforcing agent is preferably 5 to 10 parts by weight based on 100 parts by weight of the pretreated starch starch. When the content of the reinforcing agent is 5 parts by weight or less, the strength of the final product decreases, and when it exceeds 10 parts by weight, the processability of the final product decreases.

The antioxidant is to prevent the product from being automatically oxidized by oxygen in the air when a product such as a food container is produced using the eco-friendly composition of the present invention, and a lemon acid resin, a phenolic antioxidant, or a phosphate-type antioxidant is used. Can be used. As the phenolic antioxidant, 4,4'-methylene-bis(2,6-di-t-butylphenol), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)pro Cypionate, pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)) propionate, etc. may be used, and as the phosphate-type antioxidant, tris (2,4- Di-t-butylphenyl)phosphate or bis(2,4-di-t-butylphenylpentaerythritol)diphosphate and the like may be used.

The content of the antioxidant is preferably 0.2 to 2 parts by weight based on 100 parts by weight of the pretreated starch starch, and when the content of the antioxidant is outside the above range, there is a concern that the transparency and heat resistance of the final composition may be lowered.

The thermal stabilizer used in the present invention is to prevent and suppress thermal deterioration, photo deterioration, and oxidative deterioration that may occur in the processing process of manufacturing a product using the composition of the present invention, and as the thermal stabilizer, tin, calcium , Zinc, and the like may be used.

In addition to the above components, the composition of the present invention may optionally use other additives such as a lubricant, a wax, a colorant, a crystallization accelerator, a light stabilizer or an ultraviolet absorber within the range not impairing the effect of the present invention.

The biodegradable plastic composition of the present invention stably controls the biodegradation rate, improves hydrolysis resistance and heat resistance, and can maintain transparency, and thus materials for agriculture, forestry and fishing (film, sheet, planting container, fishing line, net, etc.) , Civil engineering materials (seedling nets, sandbags, etc.), containers and packaging for storing food, especially biodegradable plastic moldings such as films, sheets, fibers, bottles and plates, etc.

Another object of the present invention is to provide a method of preparing the eco-friendly composition of the present invention. The method of preparing the composition of the present invention comprises the following steps.

Preparing the eco-friendly composition of the present invention;

Preparing a starch concentrate solution by mixing 100 to 200 parts by weight of water based on 100 parts by weight of the pretreated starch starch and the pretreated starch starch;

Mixing the concentrated starch solution and 30 to 50 parts by weight of aluminum hydroxide based on 100 parts by weight of the pretreated starch starch and then stirring at 130 to 140° C. for 10 to 20 minutes;

Mixing a polylactic acid, a carbodiimide compound, and a silane coupling agent in the mixture of the above step and stirring for 30 minutes to 1 hour;

Mixing a titanium dioxide crystal surface-treated with a silane compound, a reinforcing agent, a heat stabilizer, and an antioxidant in the composition produced in the above step and stirring for 1 to 2 hours;

After disinfecting the composition produced in the above step using ultraviolet rays, cooling the composition at 10 to 20° C. for 2 to 3 hours; consists of.

The method for preparing the eco-friendly composition of the present invention can be stirred by optionally adding a lubricant, wax, colorant, light stabilizer and ultraviolet absorber to the step of mixing and stirring the titanium dioxide crystal, reinforcing agent, heat stabilizer and antioxidant. have.

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

In the examples below, starch means starch starch.

<Example 1>

After preparing a starch concentrate by mixing 100 g of starch acetate with 150 g of water, 30 g of aluminum hydroxide was mixed thereto and stirred at 130° C. for 10 minutes to obtain a mixture.

After adding 30 g of polylactic acid, 30 g of dicyclohexylcarbodiimide and 5 g of methyltrimethoxysilane to the mixture, the mixture was stirred at 130° C. for 1 hour.

To the mixture was added 1 g of titanium dioxide crystals, 8 g of talc, 3 g of tin, and 1 g of lemon acid resin, followed by stirring at 130°C for 1 hour.

The composition obtained above was sterilized by applying ultraviolet rays at 130° C. and then cooled at 20° C. for 3 hours to obtain a composition.

<Example 2>

After mixing 100 g of hydroxyalkyl starch with 150 g of water to prepare a starch concentrate, 30 g of aluminum hydroxide was mixed thereto and stirred at 130° C. for 10 minutes to obtain a mixture.

After adding 30 g of polylactic acid, 30 g of diisopropylcarbodiimide, and 5 g of phenyltrimethoxysilane to the mixture, the mixture was stirred at 130° C. for 1 hour.

To the mixture, 1 g of titanium dioxide crystals, 8 g of talc, 3 g of zinc, and 1 g of 4,4'-methylene-bis(2,6-di-t-butylphenol) were added, followed by stirring at 130° C. for 1 hour.

The composition obtained above was sterilized by applying ultraviolet rays at 130° C. and then cooled at 20° C. for 3 hours to obtain a composition.

<Example 3>

After mixing 100 g of carboxymethyl starch with 150 g of water to prepare a starch concentrate, 30 g of aluminum hydroxide was mixed thereto, followed by stirring at 130° C. for 10 minutes to obtain a mixture.

After adding 30 g of polylactic acid, 30 g of dimethylcarbodiimide and 5 g of phenyltrimethoxysilane to the mixture, the mixture was stirred at 130° C. for 1 hour.

1 g of titanium dioxide crystals, 8 g of talc, 3 g of zinc, and 1 g of tris(2,4-di-t-butylphenyl)phosphate were added to the mixture, followed by stirring at 130°C for 1 hour.

The composition obtained above was sterilized by applying ultraviolet rays at 130° C. and then cooled at 20° C. for 3 hours to obtain a composition.

<Example 4>

After preparing a starch concentrate by mixing 100 g of starch phosphate with 150 g of water, 30 g of aluminum hydroxide was mixed thereto and stirred at 130° C. for 10 minutes to obtain a mixture.

To the mixture was added 30 g of polylactic acid, 30 g of diisopropylcarbodiimide, and 5 g of phenyltrimethoxysilane, followed by stirring at 130° C. for 50 minutes.

To the mixture was added 1 g of titanium dioxide crystals, 8 g of talc, 3 g of zinc, and 1 g of pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)) propionate at 130° C. Stir for 1 hour.

The composition obtained above was sterilized by applying ultraviolet rays at 130° C. and then cooled at 20° C. for 3 hours to obtain a composition.

After preparing a specimen (10 cm wide, 10 cm long) using the eco-friendly composition of the present invention obtained through Examples 1 to 4, the biodegradation efficiency, tensile strength and heat resistance of each specimen were tested and shown in Table 1. .

The biodegradation efficiency experiment was conducted as specified in ISO14855 to measure the oxygen demand biodegradation efficiency and the structure destruction efficiency for the analysis of the amount of CO2 produced under controllable mixing conditions. According to ISO14855, total degradable fibrin was used as a reference material in plastic material decomposition experiments. After 45 days of the experiment, when the decomposition rate of the reference material was greater than 70%, the decomposition was considered to be completely decomposed. In general, it is known that the degradable polyethylene film should not have a decomposition rate of less than 20%, and should not be less than 15% for packaging products. According to the results of this experiment, the composition of the present invention can be said to be completely biodegradable.

In the test for hydrolysis resistance, the specimens were placed in an atmospheric composition chamber maintained at 80° C. and 90% RH, respectively, for a certain period (100 hours), and the ratio (%) of the tensile strength after the test to the value before the test was calculated. For samples with a high tensile strength ratio (80% or more), the hydrolysis resistance was set as'good'.

For the tensile strength test, a dumbbell-shaped specimen was prepared and tested, and in the heat resistance test, the specimens were placed in hot water at 100°C for 5 hours and the ratio of the tensile strength after the test was calculated with respect to the value before the test, and the ratio of high tensile strength of 80% or more. The heat resistance was set as'good' for the sample having

In the test for transparency, the haze (cloudiness) of the film specimen was measured using a haze meter according to JIS K7105'Evaluation Method of Optical Properties of Plastics', 6.4'Haze (cloudiness)'. For samples with low haze (less than 10%), transparency was set as'good'.

division Example 1 Example 2 Example 3 Example 4 Biodegradation rate (%) 88.5 89.2 91.6 93.1 Tensile strength (MPa) 51.2 53.3 52.5 55.1 Hydrolysis resistance (%) Good(89.1) Good(89.5) Good(90.1) Good(91.1) Heat resistance (%) Good(92) Good(90) Good(91) Good(91) transparency(%) Good(2.5) Good(3.3) Good(2.7) Good(3.6)

As shown in the results shown in Table 1 above, the eco-friendly composition provided by the present invention has excellent processability such as biodegradability, heat resistance, hydrolysis resistance, and tensile strength, so that it can replace conventional plastic products, and has a high biodegradation rate. Even if it is prevented in natural conditions, it can be decomposed by sunlight and microorganisms to prevent environmental pollution, so it can replace various plastic products in the future.

The present invention is industrially applicable.

Claims (11)

delete delete delete delete delete As for a method for preparing a composition capable of natural decomposition, the method includes;
Preparing a starch concentrate solution by mixing 100 to 200 parts by weight of water based on 100 parts by weight of the pretreated starch starch and the pretreated starch starch;
Mixing the concentrated starch solution with 30 to 50 parts by weight of aluminum hydroxide based on 100 parts by weight of the pretreated starch starch and then stirring at 130 to 140° C. for 10 to 20 minutes;
Mixing a polylactic acid, a carbodiimide compound, and a silane coupling agent to the mixture of the above step and stirring for 30 minutes to 1 hour;
Mixing a titanium dioxide crystal surface-treated with a silane compound, a reinforcing agent, a heat stabilizer, and an antioxidant in the composition produced in the above step and stirring for 1 to 2 hours;
After disinfecting the composition produced in the above step by using ultraviolet rays, cooling the composition at 10 to 20° C. for 2 to 3 hours; a method for preparing a composition comprising: The method of claim 6, wherein the carbodiimide compound is dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcar Method for producing a composition, characterized in that any one selected from bodyimide, diphenylcarbodiimide, di-t-butylcarbodiimide, and di-β-naphthylcarbodiimide The method of claim 6, wherein the coupling agent is any one selected from 3methylethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane. The method of claim 6, wherein the antioxidant is 4,4'-methylene-bis(2,6-di-t-butylphenol), octadecyl-3-(3,5-di-t-butyl-4-hydro Roxyphenyl) propionate, pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)) propionate, tris (2,4-di-t-butylphenyl) Phosphate or bis (2,4-di-t-butylphenylpentaerythritol) diphosphate method for producing a composition, characterized in that any one selected from The method of claim 6, wherein the pretreated starch starch is any one selected from oxidized starch, carboxymethyl starch, hydroxyalkyl starch, esterified starch, acetic acid starch, and phosphate starch.

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