KR101270363B1 - Method of preparing naturally degradable food container using coated inorganic filler powder - Google Patents

Abstract

PURPOSE: A natural resolvable food container manufacturing method using coated inorganic powder is provided to uniformly maintain colors of products and, at the same time, to prevent the separation and session of an inorganic filler by increasing binding power between the inorganic filler and base material resin. CONSTITUTION: A resolvable food container manufacturing method using coated inorganic powder comprises as follows: a step of obtaining aluminum hydroxide powder which is treated with silane; a step of coating a photolysis agent on the surface of compound powder which is produced by mixing silica aero gal powder with the aluminum hydroxide powder which is treated with silane; a step of coating biodegradable resin on the surface of the compound powder which is produced by mixing the silica aero gal powder with the aluminum hydroxide powder which is treated with silane; a step of mixing the powder coated with the photolysis agent and the powder coated with the biodegradable resin, with polyolefin resin, and extruding a mixture of the powder coated with the photolysis agent and the powder coated with the biodegradable resin, with polyolefin resin; and a step of molding by the use of granules which are obtained by granulating the extrusion of the mixture.

Description

Method of preparing naturally degradable food container using coated inorganic filler powder

The present invention relates to a method for manufacturing a naturally degradable food container using a coated inorganic powder, and more particularly, excellent transparency, kneading with resin, excellent physical strength, photodegradability and biodegradability, and the like. The present invention relates to a method for producing a food container having excellent natural decomposition performance.

In recent years, the use of disposable food containers using plastics is increasing according to changes in living patterns such as eating out culture and delivery culture. Waste plastics discarded after being used as such disposable food containers are not decomposed even after a long time, and when the land is contaminated and incinerated, the air pollution such as dioxin and carbon dioxide is released, causing a great deal of environmental pollution.

In order to solve these problems, a plastic using an aliphatic polyester resin as a main component may be used, but the aliphatic polyester resin is not widely used because of its high price.

In addition, plastics having increased biodegradability by mixing a biodegradable natural polymer with a resin are also known. For example, Korean Patent Publication No. 96-0012445 proposes a biodegradable polyethylene composition using starch, maleic anhydride, methacrylic anhydride, maleimide, acrylic acid, and methacrylic acid in polyethylene, and a method of preparing the same. However, the composition described in the patent has a problem in that the bond between starch and polyethylene is not high and the processability of the container is bad.

In addition, photodegradable resin compositions are known which comprise an inorganic filler such as calcium carbonate in a polyethylene or polypropylene resin. When inorganic fillers such as potassium carbonate are used, the amount of resin that needs to be photodegraded is shortened, and the decomposition time is shortened. When the resin starts to be decomposed from the surface, the inorganic filler reacts with moisture in the air or in the ground, and the separated portion forms a microspace. Therefore, the surface area which can be in contact with moisture is increased to promote decomposition of the resin, thereby improving photodegradability. For example, Korean Patent No. 657413 describes an example of using calcium carbonate as an inorganic filler, polyethylene and polypropylene as photodegradable resins, and stearin as a photodegradation accelerator, and Korean Patent Publication No. 2009-0012383 Examples include using silica airgel resins as inorganic fillers, polyethylene and polypropylene as photodegradable resins, and stearin as photolysis accelerators.

However, when the inorganic filler is mixed and used as described above, the inorganic filler may be detached from the container due to low bonding strength with the synthetic resin, and the resin composition is stretched during molding, resulting in poor workability. This is likely to occur.

In addition, the Republic of Korea Patent No. 0915521 has proposed a technique for improving the bond between the inorganic filler and the resin by using a non-toxic starch having an adhesive function. However, when a simple mixture of non-toxic starch is used, the bondability with the resin is increased, but not enough, and the compatibility with the inorganic filler is not high. Biodegradability is achieved by using only a small amount of starch for adhesion. There was a problem that the effect is not given.

In addition, Korean Patent Laid-Open Publication No. 2009-0055761 proposed a composition for preparing a breathable film comprising a biodegradable polymer resin and a filler, and a photodegradant is coated on the surface of the filler. However, the composition described herein uses the base resin as the biodegradable resin, and in the state of the composition, the binding force of the biodegradable resin and the filler may be increased by coating the photodegradant, but the biodegradable resin and the filler are separated through the stretching process. As a method for producing a breathable film, it is only for expressing the breathability of a film made of a biodegradable polymer resin, and is less relevant for producing a food container.

In addition, Korean Patent No. 1210301 proposes a method of manufacturing a food container having both a photodegradable and biodegradable function while effectively preventing separation of the inorganic filler by increasing the bonding strength of the inorganic filler and the base resin having a weak bonding strength. However, in this technology, since silicon dioxide and calcium carbonate are used as the inorganic filler, there is a problem in low transparency because there is a difference in refractive index with the polymer resin. In the case of calcium carbonate, there is a problem that the color of the container is inferior because of the high refractive index difference with the polymer resin, and silicon dioxide has better transparency than calcium carbonate, but when used alone, it is used as a silica airgel, so it scatters around. As it is difficult to accurately measure and maintain the composition uniformly, there is a problem that it is difficult to maintain a constant color for each lot of products.

Meanwhile, in the case of aluminum hydroxide, which is used as a kind of inorganic filler in the polymer resin, there is a need to coat the outside of the filler with a material having high compatibility because of its incompatibility with the resin. In the case of conventional aluminum hydroxide powder, there are many voids. Therefore, the liquid coating material is absorbed into the pores, so that the coating performance is reduced, and the absorbed aluminum hydroxide has a problem in that it is not easy to control the viscosity, so that it is difficult to be applied to food containers.

However, since aluminum hydroxide has a light transmittance refractive index similar to that of a polymer resin such as polypropylene, when the above problem is solved, the color of the obtained container can be made beautiful and accurate metering and feeding can be solved. It is expected to develop a technology that can be applied to this situation was a great situation.

The present invention was developed in view of the above situation, and in manufacturing a food container including an inorganic filler, reducing the amount of silica airgel used as an inorganic filler, instead of using a mixture of aluminum hydroxide to increase the transparency of the food container manufactured More beautiful and improve the physical properties, and also keep the color of the product uniform, and increase the bonding strength between the inorganic filler and the base resin to prevent the separation and detachment of the inorganic filler and impart photodegradability and biodegradability. The present invention provides a method of making a biodegradable food container.

According to an aspect of the present invention,

(a) treating aluminum hydroxide with organic silane to obtain a silane-treated aluminum hydroxide powder;

(b) mixing the silica airgel powder with the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a photodegradant;

(c) mixing the silica airgel powder and the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a biodegradable resin;

(d) kneading and extruding the powder coated with the photodegradant obtained in (b) and the powder coated with the biodegradable resin obtained in (c) with a polyolefin resin;

(e) granulating the extrudate obtained in (d); And

(f) molding using the granules obtained in (e) above

It provides a method for producing a naturally degradable food container comprising a.

Referring to the features and advantages of the method for producing a biodegradable food container according to the method of the present invention.

First, the mixture of silica airgel powder and aluminum hydroxide powder can be used as an inorganic filler to improve the transparency of the product, and the problem of powder scattering and product color unevenness, which was a problem of silica airgel powder by using relatively high density aluminum hydroxide, can be solved. I can solve it. In addition, the problem of high viscosity due to oil absorption of aluminum hydroxide was solved by improving the processability by pretreating the surface of the aluminum hydroxide powder with organic silane.

Therefore, by using the manufacturing method according to the present invention, the surface of the inorganic filler can be coated with a photodegradable agent and a biodegradable resin in advance, thereby minimizing the direct contact of the inorganic filler with the polyolefin resin by combining the coated materials, thereby improving the bonding strength of the composition. It can be increased to prevent the inorganic filler from being detached during the manufacturing process and after the production into the food container.

In addition, since the photodegradation agent and the biodegradable resin is used together with the coating, it is possible to have a natural degradability even when exposed to the sun as well as embedded in the ground.

In addition, the biodegradability and photodegradability can be further improved by using the plant fiber powder in the present invention.

The method for producing a biodegradable food container according to the present invention is characterized by solving the problems that silica airgel has by using a mixture of silica airgel and aluminum hydroxide powder as an inorganic filler, in particular through the pre-treatment in using aluminum hydroxide powder It is a feature of the invention to solve the problem of oil absorption to increase the processability during coating.

Specifically, the method for producing a biodegradable food container according to the present invention

(a) treating aluminum hydroxide with organic silane to obtain a silane-treated aluminum hydroxide powder;

(b) mixing the silica airgel powder with the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a photodegradant;

(c) mixing the silica airgel powder and the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a biodegradable resin;

(d) kneading and extruding the powder coated with the photodegradant obtained in (b) and the powder coated with the biodegradable resin obtained in (c) with a polyolefin resin;

(e) granulating the extrudate obtained in (d); And

(f) molding using the granules obtained in (e) above

.

Hereinafter will be described in detail by dividing the method for producing a naturally degradable food container according to the present invention in each step.

(1) pretreatment step of aluminum hydroxide powder

The silane treatment treated with aluminum hydroxide with organosilanes is R 1 _n Si (OR ₂ ) _4-n (n = 0-3, R ₁ = C ₁ -C 6 alkyl group, OR ₂ = methoxy, ethoxy, acetoxy group) After dispersing the colloidal solution in which the aluminum hydroxide is dispersed in the solvent in the organic silane, it may be performed by stirring for 1 to 10 hours.

More specifically, about 0.1 to 50 parts by weight of the organic silane based on 100 parts by weight of the aluminum hydroxide solution is added to the aluminum hydroxide solution to form organic groups on the surface of the aluminum hydroxide particles in the solution, and passed through the reactor to dehydrate and condensate the reaction. Aluminum hydroxide powder surface-treated with an organic group is formed through. At this time, the aluminum hydroxide solution is preferably in contact with the organic silane in the colloidal solution as the aluminum hydroxide is dispersed in a colloidal state in a solvent such as water or alcohol.

The organosilane used in the present invention is preferably R 1 _n Si (OR ₂ ) _4-n (n = 0-3, R ₁ = C ₁ -C 6 alkyl group, OR ₂ = methoxy, ethoxy, acetoxy group) Specific examples thereof include dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetraethoxysilane, and the like.

At this time, the treatment of the aluminum hydroxide surface with the organic silane is formed by stirring for 1 to 10 hours at room temperature to form an aluminum hydroxide inorganic material formed with an organic group and passing it through a reactor. At this time, the reactor is a heating device to increase the temperature to 100 ~ 300 ℃ dehydration and condensation reaction of the aluminum hydroxide inorganic solvent and the organic group formed organic solvent for 1 to 10 hours to produce a powder-shaped aluminum hydroxide inorganic particles of the surface treatment is completed have.

(2) photolysate coating step

A process of coating a mixture of silica airgel powder and silane-treated aluminum hydroxide powder to be used in the method for producing a biodegradable food container according to the present invention with a photodegradant. The silica airgel used in the present invention has a porosity of about 80 to 99.9% and a pore size in the range of 1 to 100 nm, and thus is an environmentally friendly insulating material and an extremely low material because it has excellent properties such as ultra-light weight, ultra-thermal insulation, and ultra-low dielectric. There is much research in the application of materials such as dielectric thin films and catalyst carriers. However, the silica airgel is scattered due to its very low apparent density and small particle size, which makes it difficult to handle and not easy to fill. In order to solve this problem, the present invention is characterized by using a mixture of silica airgel and aluminum hydroxide powder having a similar external density and a relatively high density. However, the aluminum hydroxide has a problem of excessively absorbing the liquid photodegradable material and biodegradable resin in the impregnation process for the coating to be carried out after the oil absorption amount is large, so as to solve this problem, pre-treated before the coating as in step (1) Use it.

In this step, the mixing ratio of the silica airgel powder and the silane-treated aluminum hydroxide powder is preferably 1: 100 to 50: 100 by weight, more preferably 10: 100 to 20: 100.

The coating in this step is, for example, by mixing 30 to 200 parts by weight of a photodegradant to 100 parts by weight of the mixture of the silane-treated aluminum hydroxide powder and silica airgel powder obtained in the above (1) for 1 to 30 minutes It may proceed by heat treatment. At this time, the heat treatment temperature is a temperature to be coated in a state in which the photolytic agent is sufficiently melted, and may vary depending on the type of the photolytic agent, but in the above temperature range, the photolytic agent used in the present invention may be sufficiently melted. It is desirable to maintain the range. On the other hand, the coating process is coated by high-speed kneading while mixing and stirring the molten photolysing agent and powder mixture, and the remaining material is dried through a drying furnace to coat the photolysing agent on the surface of the inorganic filler powder.

In general, the inorganic filler is incompatible with the nonpolar polyolefin component and is easily peeled off. Therefore, in the present invention, the surface of the filler is coated to increase the bonding strength. On the other hand, in the case of aluminum hydroxide is impregnated for coating with a photodegrading agent, the amount of oil absorption of the photodegradant inside the pores increases, so coating is not easy, and when the amount of oil absorption increases, the viscosity rises too much and the processability worsens. This problem solves the problem of oil absorption by pretreating the surface of the aluminum hydroxide powder in advance as in step (1). Examples of photodegradants used in the present invention include, but are not limited to, stearin, stearic acid, steroidiolein or mixtures thereof. These photodegradants have good compatibility with polyolefins and biodegradable resins, and thus serve to enhance processing stability by preventing the inorganic filler from being separated or detached during processing. On the other hand, the photodegrading agent is easily decomposed by the sun, and the decomposed site acts as a void, so that the binding force between the base resin and the inorganic filler is weakened and the inorganic filler is detached, so that the decomposition of the polyolefin resin occurs easily.

(3) biodegradable resin coating step

It is a process of coating the mixture of the silane-treated aluminum hydroxide powder and silica airgel powder obtained by said (1) used for the manufacturing method of the naturally-degradable food container which concerns on this invention with biodegradable resin. In this step, the mixing ratio of the silica airgel powder and the silane-treated aluminum hydroxide powder is preferably 1: 100 to 50: 100 by weight, more preferably 10: 100 to 20: 100.

The coating in this step may be performed by, for example, mixing 10 to 200 parts by weight of the biodegradable resin with 100 parts by weight of the inorganic filler powder mixture and heat-treating at 70 to 200 ° C. for 1 to 30 minutes. At this time, the heat treatment temperature is a temperature that allows the biodegradable resin to be coated in a sufficiently melted state, and may vary according to the type of biodegradable resin, but most biodegradable resins may be sufficiently melted in the above temperature range. It is desirable to maintain the temperature range. On the other hand, the coating process is coated by high-speed kneading while mixing and stirring the molten biodegradable resin and inorganic filler powder mixture, and the residual material is dried through a drying furnace to coat the biodegradable resin on the surface of the inorganic filler powder.

As described above, the inorganic filler powder is incompatible with the polyolefin component and is easily peeled off, and is incompatible with biodegradable resins. This problem is solved by coating the biodegradable resin through heat treatment on the surface of the inorganic filler powder in the present invention. The biodegradable resin used in the present invention may be used alone or blended with all conventionally known biodegradable resins. Examples of such biodegradable resins include, but are not limited to, starch, polybutylene succinate (PBS), polybutylene-adipate copolymers, polycaprolactone, polylactic acid or mixtures thereof. It can be used in various ways. Since such biodegradable resins have good compatibility with polyolefins and photodegradants, the biodegradable resins serve to enhance processing stability by preventing the inorganic filler powder from being separated or detached during processing. On the other hand, such biodegradable resins are easily decomposed by moisture, and the sites decomposed as voids act as voids, thereby weakening the bonding force between the base resin and the inorganic filler powder and decomposing the polyolefin resin as the inorganic filler powder is detached.

Steps (2) and (3) should be interpreted as being able to proceed in any order.

(4) kneading and extrusion step

The inorganic filler powder coated with the photodegradant obtained in step (2) and the inorganic filler powder coated with the biodegradable resin obtained in step (3) are kneaded with a polyolefin resin and extruded.

The polyolefin used in the present invention is preferably polypropylene, polyethylene or mixtures thereof, and various kinds can be used without limitation. Specific examples thereof include high density polyethylene, polypropylene, copolymers thereof, copolymers with ethylene-vinyl acetate (EVA), and the like.

Examples of the content of each component to be mixed in the step (4), for example, the inorganic filler powder coated with a photodegradant and the inorganic filler powder coated with a biodegradable resin are 10 to 200 parts by weight and 50 parts by weight, respectively, based on 100 parts by weight of the polyolefin resin. It is preferable to knead to ˜300 parts by weight. When used in the above range because both photodegradability and biodegradability can be exhibited smoothly. Other additives usable in the field of the present invention, for example, antioxidants, dispersants, colorants and the like can be added in various ways depending on the quality required.

In order to further improve the biodegradability and photodegradability of the final product in the present invention may further include a plant fiber powder in the kneading process, examples of such plant fiber powder is chaff, corn husk, bamboo, sugar cane, straw, Plant fiber materials such as pulp may be used as raw materials, and the materials may be used alone or in combination of two or more thereof. The plant fiber powder used at this time is 50 to 300 mesh size is suitable for kneading with the resin and decomposition efficiency of the final product.

In addition, the plant fiber powder is preferably used in the range of 1 to 200 parts by weight based on 100 parts by weight of polyolefin resin, and may be changed according to the required characteristics of the final product.

The specific process of kneading and extrusion may be used as it is or modified by the method described in Republic of Korea Patent No. 0915521. For example, a mixed raw material is introduced into an extruder, and the first heating is performed at 190 to 200 ° C., and the first heated mixed raw material is secondly heated at 210 to 220 ° C., and the second heated mixed raw material is heated. After the third heating at 180 ~ 190 ℃ again, the third heated material mixture is heated to 4 times at 230 ~ 240 ℃ can be extruded while repeating the melting and fusion. However, the temperature range is only one example, and a person skilled in the art may variously modify the heating step according to the required characteristics of the product. The extruder to be used is not particularly limited, but a single screw extruder or a twin screw extruder can be used. Especially, in the case of a twin screw extruder, both a coaxial rotation and a bidirectional rotation can be used, but in order to prevent decomposition of a biodegradable resin, a coaxial rotation type is used. More preferred.

(5) granulation step

The extrudate obtained in step (4) passes through a cooling tank, preferably a cooling tank including cooling water in a range of 10 to 30 ° C. for about 10 to 30 seconds, and is cut into pellets. The granules thus prepared are made to have a moisture content of 1000 ppm or less, preferably 500 ppm or less through dehumidification drying to produce final granules.

(6) forming step

It is a process of manufacturing a container form using the granulation obtained in the step (5). Production of the container form can be made by injection or extrusion of granules, with no particular limitation. For example, in the form of an extruded form, a resin composition in a granulated form is introduced into a sheet extruder and melted to form a gel, and then passed through a roller and a roller to form a sheet. Subsequently, the obtained sheet is vacuum pressed or pressed with a press to produce a container shape.

As mentioned above, the manufacturing method of the naturally-degradable food container which concerns on this invention was demonstrated in detail at each step. When the food container is prepared by the method according to the present invention, before the kneaded mixture of olefin resin, silica aerogel and aluminum hydroxide is kneaded, the filler is thermally coated with a photodegradant and a biodegradable resin to coat the filler with the olefin resin. Since it is possible to increase the separation of the filler can be prevented after processing or manufacturing. In this process, it is difficult to maintain the uniformity of color due to the problem of scattering of silica airgel and difficulty in weighing. Therefore, to solve this problem, silica airgel is minimized by using silica hydroxide pretreated with silane. Can solve the problem of using and enhance the physical properties and product uniformity. In addition, in some cases, by additionally containing the plant fiber powder can be easily used as a naturally degradable food container because it can be easily decomposed by ultraviolet rays or moisture when discarded after use.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited by Examples.

Example 1

(1) Silane Treatment of Aluminum Hydroxide

10 parts by weight of an organic silane was added to 100 parts by weight of a colloidal solution obtained by dispersing aluminum hydroxide in water as a mineral solution (solid content: water = 30:70), and methyl trimethoxysilane was used as the organic silane. The reaction time was adjusted to 6 hours and stirred at 700 to 800 rpm at room temperature to synthesize the sol, and then heated to 150 ° C. to react for 7 hours to obtain aluminum hydroxide powder surface-treated with an organic group.

(2) photodegradable coating of filler powder

Silica airgel as the inorganic filler and the silane-treated aluminum hydroxide powder obtained above were mixed at a ratio of 10: 100, respectively, to obtain a powder mixture, and based on 100 parts by weight of 100 parts by weight of stearin as a photodegradant, 120 parts by weight was mixed. Stearin was coated on the surface of the powder mixture by heat treatment for 20 minutes at. Specifically, the powder mixture and stearin were mixed and stirred at the above temperature and coated by high-speed kneading while the residual material was dried at the same temperature through a drying furnace to coat stearin on the surface of the powder mixture.

(3) biodegradable resin coating of filler powder

Subsequently, the silica airgel and the silane-treated aluminum hydroxide powder obtained above were mixed at a ratio of 10: 100, respectively, to obtain a powder mixture, and 100 parts by weight of polybutylene succinate (PBS) as a biodegradable resin was added to the content of 100 parts by weight. The polybutylene succinate was coated on the mixed powder surface by heat treatment at 120 ° C. for 1 to 30 minutes. Specifically, the coating process is coated by high-speed kneading while mixing and stirring the molten polybutylene succinate and the powder mixture at the set temperature and the residual material is dried through a drying furnace to polybutylene succinate on the surface of the mixed powder Was coated.

(4) kneading, granulation and molding

Subsequently, a twin screw extruder in which the internal temperature is maintained at 180 to 240 ° C. by mixing 100 parts by weight of the stearin-coated powder mixture and 100 parts by weight of the polybutylene succinate-coated powder mixture with respect to 100 parts by weight of polypropylene resin Extruded through and then cut to a predetermined size by passing through a cooling bath maintained at 15 ℃ granules were prepared.

Subsequently, the granulation was sheeted by passing through a sheet extruder, and the manufactured sheet was manufactured using a vacuum press molding machine to prepare a food container having a predetermined size.

[Example 2]

100 parts by weight of the stearin-coated powder mixture and 100 parts by weight of the polybutylene succinate-coated powder mixture and 100 parts by weight of the chaff powder ground to 100 mesh size are mixed and kneaded with respect to 100 parts by weight of polypropylene resin. Then, a food container was manufactured in the same manner as in Example 1.

[Example 3]

It is the same as Example 1 except only using starch as biodegradable resin.

Example 4

A food container was manufactured in the same manner as in Example 1, except that the silica airgel and the silane-treated aluminum hydroxide powder were mixed in an amount of 20: 100, respectively, as an inorganic filler to obtain a powder mixture.

Comparative Example 1

Pellets were prepared by kneading 100 parts by weight of polypropylene, 100 parts by weight of powder mixture, 50 parts by weight of stearin and 50 parts by weight of polybutylene succinate at once. The kneading process and the pelletized sheet and the conditions for forming the food container were the same as in Example 1.

Comparative Example 2

Pellets were prepared by kneading 100 parts by weight of silica airgel coated with stearin and 100 parts by weight of silica airgel coated with polybutylene succinate resin. The kneading process and the pelletized sheet and the conditions for forming the food container were the same as in Example 1. During the kneading process, the silica airgel was scattered severely, which made it difficult to accurately measure the weight.

[Comparative Example 3]

100 parts by weight of silane pretreated aluminum hydroxide was coated with 100 parts by weight of stearin and 100 parts by weight of polybutylene succinate resin in the same manner as in Example 1. In the process of impregnating with the liquid material, it was confirmed that the coating on the surface of the powder did not proceed properly by absorbing excessive amount of the liquid material in the aluminum hydroxide and excessively increasing the viscosity.

The aluminum hydroxide powder and the silica aerogel coated with stearin and polybutylene succinate, respectively, were mixed in the same amount as in Example 1 to obtain a powder mixture, and the same polymer resin as in Example 1 The other ingredients were kneaded to prepare a dish container in the same manner as in Example 1.

(1) Property evaluation result

Table 1 shows the results of evaluating the physical properties using the sheets obtained in Examples 1 to 4 and Comparative Examples 1 to 3.

Item exam
Way Exam conditions unit Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Melt Index ASTM D1238 200 ℃ / 5kg g / 10 min 13 12 11 13 11 14 14 importance ASTM D792 23 ℃ - 1.01 1.00 1.02 1.02 1.01 1.02 1.01 Molding
Shrinkage rate ASTM D955 - % 0.8 1.0 0.9 0.8 0.9 1.0 1.1 Yield Point Tensile Strength ASTM D638 50mm / min kg / cm ² 232 230 240 236 225 235 229 curve
Elastic modulus ASTM D790 15mm / min kg / cm ² 18,500 16,500 16,000 17,500 16,800 17,000 16,500

(2) inorganic filler desorption test results

As a result of visual evaluation using the sheets obtained in Examples 1 to 4 and Comparative Examples 1 to 3, in the case of Examples 1 to 4, no fillers exposed on the surface were found. It was confirmed that some of the fillers were detached and exposed.

(3) Photodegradability and biodegradability evaluation results

Photodegradability was evaluated using the xenon test machine in the space maintained at 10 ° C using the containers obtained in Examples 1 to 4 and Comparative Examples 1 to 3. In addition, biodegradability was evaluated in a state in which the humidity was maintained at 50% in a space kept at 10 ° C. with light removed. The point at which the flexural modulus falls below 1000 was evaluated as photodegradation, and the results are shown in Table 2.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Photolysis Time (hr) 8800 8750 8850 8900 8700 8750 8860 Biodegradation time (hr) 14800 14500 15000 15100 14500 14600 15000

From the above results, it was confirmed that there is no significant difference in photodegradability and biodegradability in the case of the food container manufactured by the method according to the present invention compared with the case of the food container manufactured by the conventional general kneading method.

Claims (5)

(a) 1 to 10 hours after dispersing a colloidal solution in which aluminum hydroxide is dispersed in a solvent in at least one organic silane selected from dimethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and tetraethoxysilane Stirring to obtain a silane-treated aluminum hydroxide powder by dehydration and condensation reaction for 1 to 10 hours by raising the temperature to 100 ~ 300 ℃ in the reactor;
(b) mixing the silica airgel powder with the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a photodegradant;
(c) mixing the silica airgel powder and the silane-treated aluminum hydroxide powder obtained in (a) and coating the surface of the mixed powder with a biodegradable resin;
(d) kneading and extruding the powder coated with the photodegradant obtained in (b) and the powder coated with the biodegradable resin obtained in (c) with a polyolefin resin;
(e) granulating the extrudate obtained in (d); And
(f) molding using the granules obtained in (e) above
Method for producing a naturally degradable food container comprising a.
delete The method of claim 1, wherein the coating of the photodegradant in the step (b) is characterized in that the progress by heat treatment for 1 to 30 minutes at 100 ~ 150 ℃ by mixing 30 to 200 parts by weight of the photodegradant to 100 parts by weight of the mixed powder Method for producing a degradable food container.
The method of claim 1, wherein the coating of the biodegradable resin in the step (c) is characterized in that by proceeding the heat treatment for 1 to 30 minutes at 70 ~ 200 ℃ by mixing 10 to 200 parts by weight of the biodegradable resin to 100 parts by weight of the mixed powder Method for producing a naturally degradable food container.
The method according to claim 1, wherein in step (d) during the kneading of the powder and the polyolefin resin chaff, corn cob, bamboo, sugar cane, straw, pulp, characterized in that further mixing the plant fiber powder consisting of two or more selected from the pulp. The manufacturing method of the naturally-degradable food container made into.