KR102324258B1 - Biodegradable resin composition and pellet manufactured using the same for food vessel - Google Patents

Abstract

The present invention relates to a biodegradable resin composition and pellets for food containers prepared therefrom, and more particularly, PLA (Poly Lactic Acid), PBAT (PolyButylene Adipate-co-Terepthalate), starch powder, rice bran powder, calcium carbonate, wax , a biodegradable resin composition comprising a crosslinking agent and an antioxidant, and pellets for food containers prepared therefrom. The biodegradable resin composition according to the present invention produces a food container with natural raw materials, so there is no elution of environmental hormones and is lightweight, and it can greatly contribute to environmental improvement by being completely biodegradable in a natural state. It has the effect of improving the storage period.

Description

Biodegradable resin composition and pellets for food containers prepared therefrom

The present invention relates to a biodegradable resin composition and pellets for food containers prepared therefrom, and more particularly, PLA (Poly Lactic Acid), PBAT (PolyButylene Adipate-co-Terepthalate), starch powder, rice bran powder, calcium carbonate, wax , a biodegradable resin composition comprising a crosslinking agent and an antioxidant, and pellets for food containers prepared therefrom.

With the development of modern society, plastic packaging papers and containers bring convenience to life with excellent functions and low prices, and have contributed greatly to industrial development throughout the industry. is recognized as one of the biggest sources of environmental pollution.

Polystyrene is a representative thermoplastic resin and is a polymer material obtained by polymerizing a styrene monomer. Currently, styrone-based resin molded products are used in various daily necessities, kitchen products, toys, radios, VTRs, beverage containers, and food packaging containers. Among them, expandable polystyrene is mainly used for food packaging containers such as cup noodle containers, fish trays, fruit trays, and disposable lunch boxes. The expandable polystyrene refers to a mixture of polystyrene with a foaming agent such as propane, butane and pentane. This expandable polystyrene expands 5 to 25 times as it is or by putting it in a suitable mold and heating it, so that a light and strong foam molded article can be obtained. On the other hand, processing the expandable polystyrene into a sheet using an extruder is called polystyrene paper (polystyrene paper). Generally, expandable polystyrene used for food containers is commercially available in the form of polystyrene paper.

Since expandable polystyrene food containers are lightweight by foaming polystyrene, they are lighter compared to food containers made of other materials, and have the advantage of using only a very small amount of petroleum as a raw material. Expandable polystyrene food containers appeared in Japan in 1962, and after that, as self-service sales called prepackage methods in which food is prepackaged in trays and sold, have recently been widely used in Korea. In addition, in the rapidly changing modern society, disposable foods are becoming more popular among modern people who seek quick and convenient things, and the use of food packaging containers made of expandable polystyrene is also increasing.

Polyethylene is generally used for waterproofing purposes by being coated inside various food containers for reasons such as excellent food hygiene, excellent elongation, excellent processability, and low price. It causes social and environmental problems such as the release of environmental hormones by plasticizers added to plastics during the disposal process.

However, since the food packaging container is used only for storing food and is not easy to seal, there is a problem in that when a certain period of time elapses, a large amount of bacteria multiply and the food is contaminated, thereby harming health, and the recycling process is difficult and processing cost Most of them are incinerated.

Moreover, the conventional products have a high risk of releasing endocrine disruptors during use/disposal, which raises problems in terms of food hygiene and safety, and has limitations in terms of environmental destruction and recycling of resources.

Republic of Korea Patent No. 10-1407092

The present invention has been devised to solve the problems of the prior art as described above, and the object of the present invention is PLA (Poly Lactic Acid), PBAT (PolyButylene Adipate-co-Terepthalate), starch powder, rice bran powder, calcium carbonate, wax, An object of the present invention is to provide a biodegradable resin composition comprising a crosslinking agent and an antioxidant, and pellets for food containers prepared therefrom.

The present invention has been devised to solve the above problems, and contains PLA (Poly Lactic Acid), PBAT (PolyButylene Adipate-co-Terepthalate), starch powder, rice bran powder, calcium carbonate, wax, crosslinking agent and antioxidant. A biodegradable resin composition is provided.

The biodegradable resin composition is 50 to 70 parts by weight of PLA, 20 to 40 parts by weight of PBAT, 2 to 5 parts by weight of starch powder, 2 to 5 parts by weight of rice bran powder, 1 to 2 parts by weight of calcium carbonate based on 100 parts by weight of the composition, 1 to 3 parts by weight of the wax, 0.5 to 2 parts by weight of the crosslinking agent, and 0.5 to 2 parts by weight of the antioxidant.

The wax is any one of paraffin wax, liquid paraffin wax, beeswax, molda wax, emulsifying wax, candelilla wax, PE wax and PP wax, preferably PE wax or PP wax.

The crosslinking agent is dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide, 2,5-dimethyl-2,5-di-(t-) butylperoxyisopropyl)benzene and 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, preferably dicumyl peroxide.

The antioxidant is Tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane, Octadecyl 3-(3'5'-di-t-butyl-4'-hydroxyphenyl)propionate, 2,2'-Ethylidenebis [4,6-di-t-butylphenol], 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6 -(1H,3H,5H)-trione, Triethylene glycol bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], N,N'-hexamethylene bis[3-(3,5- di-t-butyl-4-hydroxyphenyl)propionamide] and Tris(2,4-di-tert-butylphenyl)phosphite, preferably Octadecyl 3-(3,5-di-tert- Use a mixture of butyl-4-hydroxyphenyl)propionate and Tris(2,4-di-tert-butylphenyl)phosphite in a weight ratio of 1:1.

The biodegradable resin composition may further include a heat-blocking agent and a UV-blocking agent, and the heat-blocking agent and UV-blocking agent further include 1-2 parts by weight of the heat-blocking agent and 1-2 parts by weight of the sunscreen based on 100 parts by weight of the composition. characterized by

The heat blocking agent is any one of Al ₂ (SO ₄ )·16-18H ₂ O, NH ₄ Fe(SO ₄ ) ₂ ·2H ₂ O, Na ₂ B ₄ O ₇ ·10H ₂ O, and the sunscreen is titanium Either dioxide or zinc oxide.

In another embodiment of the present invention, there is provided a pellet for a food container prepared from the biodegradable resin composition. The pellets can be molded and used as necessary into plastic bags, vegetable containers, food containers, trays, and the like.

The biodegradable resin composition according to the present invention produces a food container with natural raw materials, so there is no elution of environmental hormones and is lightweight, and it can greatly contribute to environmental improvement by being completely biodegradable in a natural state. It has the effect of improving the storage period.

Hereinafter, the present invention will be described in more detail.

The biodegradable resin composition according to an embodiment of the present invention includes PLA (Poly Lactic Acid), PBAT (PolyButylene Adipate-co-Terepthalate), starch powder, rice bran powder, calcium carbonate, wax, crosslinking agent and antioxidant.

The weight average molecular weight (Mw) of crystalline PLA (Poly Lactic Acid) used in the present invention may be 50,000 to 150,000, and the weight average molecular weight of amorphous PLA (Poly Lactic Acid) may be 150,000 to 250,000. In the present invention, with respect to 100 parts by weight of the biodegradable resin composition, PLA (Poly Lactic Acid) preferably contains 50 to 70 parts by weight. When the content of PLA (Poly Lactic Acid) is less than 50 parts by weight, the content of PBAT is relatively increased. If it is unsuitable and the content of PLA (Poly Lactic Acid) exceeds 70 parts by weight, molding is not performed well, and physical properties such as tensile strength and elongation of the product may be reduced.

In addition, PLA (Poly Lactic Acid) is prepared by polymerization of monomers derived from D-Lactide and L-Lactide, so that the polylactic acid contains a D-Lactide content. It is preferable to use a mixture of 9 to 15% by weight of amorphous polylactic acid and crystalline polylactic acid having a D-lactide content of 1 to 5% by weight. It is preferable that 20 to 70 parts by weight of crystalline polylactic acid and 80 to 30 parts by weight of amorphous polylactic acid are based on 100 parts by weight of polylactic acid used in the composition of the present invention. This can minimize the shape change of the molded article by using the mixing ratio of the present invention.

The poly(butyleneadipate-co-terephthalate) (PBAT) resin of the present invention is a copolymer of butylene adipate and butylene terephthalate. The addition of the cyclic esterified product contributes to prolonging the service life of the PBAT resin composition, but when the content of the cyclic esterified product in the PBAT resin composition is too high, the cyclic esterified product is a film or article may precipitate on the surface of the film or article, and affect the surface appearance performance of the film or article. In the present invention, with respect to 100 parts by weight of the biodegradable resin composition, PBAT preferably contains 20 to 40 parts by weight.

When the content of PBAT is less than 20 parts by weight, the content of PLA (Poly Lactic Acid) is relatively increased. When it exceeds parts by weight, as can be seen in the following Examples and Experimental Examples, the detection amount of formaldehyde increases, and therefore, it becomes unsuitable for use as a food container.

The starch does not contain a plasticizer or is not chemically bonded to a plasticizer, and may be at least one selected from the group consisting of raw starch, gelatinized starch, and mixtures thereof. In addition, the starch may be at least one selected from the group consisting of native starch, modified starch, and mixtures thereof. The native starch may be at least one selected from the group consisting of corn starch, tapioca starch, potato starch, sweet potato starch, wheat starch, and mixtures thereof, and the modified starch is a starch ester or starch ether. ), oxidized starch, hydrolyzed starch, hydroxyalkylated starch, and mixtures thereof may be at least one selected from the group consisting of. The starch is preferably added in an amount of 2 to 5 parts by weight based on 100 parts by weight of the biodegradable resin composition. If the content of starch is less than 2 parts by weight, physical properties such as tensile strength and elongation of the product may be lowered. .

The rice bran used in the present invention is pulverized into a fine powder so as to be about 80 to 400 mesh. In the case of less than 80 mesh, the particle size is too large and the flowability during pellet production is poor, the productivity is lowered, the quality of the final product is deteriorated due to a rough surface, the strength of the product is deteriorated, and when it exceeds 400 mesh, the particle size is very Although the product quality is excellent due to the small size, the pulverization process time is too long, which deteriorates the overall productivity and price competitiveness due to the increase in cost. The rice bran is preferably added in an amount of 2 to 5 parts by weight based on 100 parts by weight of the biodegradable resin composition. When the content of the rice bran exceeds 5 parts by weight, physical properties such as tensile strength and elongation of the product may be reduced.

Calcium carbonate is an inorganic filler component that contributes to strengthening the durability of the produced pellets, and can improve rigidity, transparency and gloss by increasing the degree of crystallinity. As the calcium carbonate, it is preferable to use a nano-sized powder in an amount of 1 to 50% by weight in terms of improving physical properties, and more specifically, 80 to 100 nano-sized powder in an amount of 10 to 30% by weight. It is better to use what is included. The calcium carbonate is preferably added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the resin composition. If the content of calcium carbonate is less than 1 part by weight, it may be difficult to expect the effect of strengthening durability and reducing cost according to its addition, and if it exceeds 2 parts by weight, physical properties such as tensile strength and elongation of the product may be reduced.

Wax has the advantage of having a low molecular weight and a low melting point, so it can also function as a lubricant aid when manufacturing an additive composition using an extruder, and has the advantage of being biodegradable into a low molecular weight material. As the wax, paraffin wax, liquid paraffin wax, beeswax, molda wax, emulsifying wax, candelilla wax, PE wax, PP wax, and the like may be used. The amount of the added wax is preferably added in an amount of 1 to 3 parts by weight based on 100 parts by weight of the biodegradable resin composition. When added in an amount of less than 1 part by weight, the role of a lubricant adjuvant is weak, and when more than 3 parts by weight is used, debris such as foreign substances is generated on the die, and the cost increases.

A crosslinking agent is added to improve heat resistance. In this case, a peroxide-based crosslinking agent may be used as the crosslinking agent, and specifically, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide, 2 At least one selected from ,5-dimethyl-2,5-di-(t-butylperoxyisopropyl)benzene and 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane can be used Such a crosslinking agent is preferably added in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the resin composition. When the amount of the crosslinking agent added is less than 0.5 parts by weight, the degree of crosslinking may decrease or crosslinking may not occur. Conversely, when the amount of the crosslinking agent added exceeds 2 parts by weight, it is not preferable because sufficient crosslinking may not be achieved and it may be difficult to control the working time.

In order to delay product deterioration, yellowing and oxidative decomposition due to early oxidative decomposition, antioxidants are additionally used to extend the oxidative biodegradation period and prevent color changes, resulting in claims due to changes during distribution of products with a long shelf life can reduce The above antioxidants react with radicals generated in the plastic to function as a radical scavenger that stabilizes the plastic, and a secondary antioxidant that functions as a peroxide decomposing agent can be used alone or in combination. .

The primary antioxidant is a phenolic antioxidant, such as Tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane, Octadecyl 3-(3'5'-di-t-butyl-4'-hydroxyphenyl) )propionate, 2,2'-Ethylidenebis[4,6-di-t-butylphenol], 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3, 5-triazine-2,4,6-(1H,3H,5H)-trione, Triethylene glycol bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], N,N'-hexamethylene At least one selected from bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide] may be used.

As the secondary antioxidant, Tris(2,4-di-tert-butylphenyl)phosphite is used as a phosphite-based antioxidant, and the antioxidant used to further prevent color change due to yellowing is Resin Composition 100 It is preferable to use 0.5 to 2 parts by weight based on parts by weight. If the content of the antioxidant is less than 0.5 parts by weight, it is difficult to prevent oxidation and yellowing.

In another embodiment of the present invention, there is provided a biodegradable resin composition further comprising a heat-blocking agent and a UV-blocking agent.

The heat blocking agent may be any one of Al ₂ (SO ₄ )·16-18H ₂ O, NH ₄ Fe(SO ₄ ) ₂ ·2H ₂ O and Na ₂ B ₄ O ₇ ·10H ₂ O, and the heat blocking agent is preferably added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the biodegradable resin composition. When the content is less than 1 part by weight, the thermal barrier effect cannot be properly exhibited, and when it exceeds 2 parts by weight, it acts as a factor to increase the unit price of the product, which can be a decisive problem of lowering price competitiveness.

The sunscreen agent may be any one of titanium dioxide or zinc oxide, and the sunscreen agent is preferably added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the biodegradable resin composition. If the content is less than 1 part by weight, the UV blocking effect cannot be properly exhibited, and if it exceeds 2 parts by weight, it acts as a factor to increase the unit price of the product, which may be a decisive problem of lowering price competitiveness.

Hereinafter, the present invention will be described in more detail through Examples and Experimental Examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

< Example 1> Preparation of biodegradable resin pellets

Rice bran was pulverized to about 150 mesh to produce rice hull powder, and then dried by heating at 100° C. for 30 minutes to prepare dried rice hull powder.

With respect to 100 parts by weight of the biodegradable resin pellet composition, the PLA (Poly Lactic Acid) 20 parts by weight, PBAT (PolyButylene Adipate-co-Terepthalate) 70 parts by weight, starch powder 3 parts by weight, rice bran powder 3 parts by weight, calcium carbonate 1 parts by weight, wax (PE wax) 1 part by weight, crosslinking agent (dicumyl peroxide) 1 part by weight, and primary antioxidant (Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) 0.5 parts by weight and 0.5 parts by weight of a secondary antioxidant (Tris(2,4-di-tert-butylphenyl)phosphite) were added to a high-speed stirrer and stirred at 400 RPM to produce a mixture.

Then, using an extruder (JTE-58HS, tween extruder, JinsanPRM, Korea) (die diameter: 58 mm, roll ratio (length/diameter): 40, barrel temperature: 170°C, screw rotation speed: 800 rpm, screw 2 kneading zones, 2 reverse zones, 1 vacuum vent zone, 1 open vent zone) Strands were made, cooled using an air-cooled conveyor belt, and then cut to a size of 2-3 mm to produce biodegradable resin pellets did.

< Example 2>

With respect to 100 parts by weight of the biodegradable resin pellet composition, 40 parts by weight of the PLA (Poly Lactic Acid) and 50 parts by weight of PBAT (PolyButylene Adipate-co-Terepthalate) were added. A pellet was prepared.

< Example 3>

With respect to 100 parts by weight of the biodegradable resin pellet composition, 50 parts by weight of the PLA (Poly Lactic Acid) and 40 parts by weight of PBAT (PolyButylene Adipate-co-Terepthalate) were added. A pellet was prepared.

< Example 4>

With respect to 100 parts by weight of the biodegradable resin pellet composition, 70 parts by weight of the PLA (Poly Lactic Acid) and 20 parts by weight of PBAT (PolyButylene Adipate-co-Terepthalate) were added. A pellet was prepared.

< Example 5> train block and UV protection

With respect to 100 parts by weight of the biodegradable resin pellet composition in the composition of Example 4, 68 parts by weight of the PLA (Poly Lactic Acid) was added, and aluminum sulfate (Al ₂ (SO ₄ ) ₃ ·18H ₂ O) was added as a thermal barrier. 1 part by weight and 1 part by weight of titanium dioxide (TiO ₂ ) as a sunscreen agent was added to prepare biodegradable resin pellets.

< Experimental example 1>

After the pellets prepared in Examples 1 to 4 were molded and processed to manufacture food packaging containers, they were tested according to the "Standard Specifications of Appliances and Containers and Packaging" to check whether heavy metals and harmful substances were contained, and the results are shown in Table 1 indicated.

item standard Example 1 Example 2 Example 3 Example 4 Arsenic (mg/L) 0.1 or less non-detection non-detection non-detection non-detection Heavy metals (mg/L) 1.0 or less 0.1 0.1 0.1 0.1 Potassium permanganate consumption (mg/L) below 10 1.5 1.5 1.5 1.5 Lead (mg/kg) 100 or less non-detection non-detection non-detection non-detection Fluorescent brightener non-detection non-detection non-detection non-detection non-detection Formaldehyde (mg/L) 4.0 and below 5.5 4.3 2.3 0.3 Cadmium (mg/kg) 100 or less non-detection non-detection non-detection non-detection

From the results of Table 1, it was found that the food packaging containers prepared by molding and processing the pellets prepared in Examples 3 and 4 were harmless to the human body and had a suitable heavy metal content according to the standard. On the other hand, it was confirmed that the food packaging containers prepared by molding the pellets prepared in Examples 1 and 2 were not suitable as food packaging containers because formaldehyde was detected above the standard standard.

< Experimental example 2> heat barrier and out of line blocking effect

After forming a food packaging container by molding the pellets prepared in Example 5, in a state containing 70% (v/v) of water at 100° C. in the container to evaluate the thermal barrier properties together with Example 4, 30 At the time point elapsed, the temperature of any point inside the container and any point outside the container was measured, and the UV protection properties were measured and compared by the method of JIS A5759. The results are shown in Table 2 below.

division Outside temperature (℃) Internal temperature (℃) Temperature difference (℃) UV-rays
Blocking rate (%) Example 4 40 44 4 20 Example 5 44 59 15 70

Referring to Table 2, the food container according to Example 4 had low thermal barrier properties, but the food container according to Example 5 showed a temperature difference of 15 between the inside and the outside of the container, confirming that it exhibited thermal barrier properties compared to Example 4. .

In addition, the UV blocking effect of Example 4 showed a UV blocking rate of 20%, but Example 5 showed a UV blocking effect of 70%.

As mentioned above, what has been described in the present invention is only an embodiment for a biodegradable resin composition, and the present invention is not limited to the above embodiment, but may be implemented in a variety of different forms, and only this embodiment is the disclosure of the present invention. For completeness, it is provided to fully inform those of ordinary skill in the art to which the present invention belongs, the scope of the invention, and the present invention is only defined by the scope of the claims.

Claims (10)

Based on 100 parts by weight of the total composition, 50 to 70 parts by weight of PLA (Poly Lactic Acid), 20 to 40 parts by weight of PBAT (PolyButylene Adipate-co-Terepthalate), 2 to 5 parts by weight of starch powder, 2 to 5 parts by weight of rice bran powder, A biodegradable resin composition comprising 1 to 2 parts by weight of calcium carbonate, 1-3 parts by weight of wax, 0.5 to 2 parts by weight of a crosslinking agent, and 0.5 to 2 parts by weight of an antioxidant,
The antioxidant is a primary antioxidant (Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) 0.5 parts by weight and a secondary antioxidant (Tris(2,4-di-tert-butylphenyl) ) phosphite) is composed of 0.5 parts by weight,
A biodegradable resin composition, characterized in that it further comprises 1 part by weight of aluminum sulfate (Al ₂ (SO ₄ )·16-18H ₂ O) as a heat-blocking agent and 1 part by weight of titanium dioxide (TiO _{2 ) as a sunscreen.}
According to claim 1,
The wax is a biodegradable resin composition, characterized in that any one of paraffin wax, liquid paraffin wax, beeswax, molda wax, emulsifying wax, candelilla wax, PE wax, and PP wax.
According to claim 1,
The crosslinking agent is dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide, 2,5-dimethyl-2,5-di-(t-) A biodegradable resin composition comprising any one of butylperoxyisopropyl)benzene and 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane.
A pellet for food containers made from the composition according to any one of claims 1 to 3.
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