KR0174649B1 - Biodegradable Resin Compositions and Manufacturing Methods Thereof - Google Patents

Abstract

The present invention blends starch, a natural substance, aliphatic copolyester, ethylene-vinyl alcohol copolymer, and ethylene-vinylacetate copolymer, and adds a small amount of plasticizer and lubricant. The purpose is to obtain an excellent biodegradable resin composition, and its technical composition is to mix starch and degradable synthetic resin, which is a natural substance, add plasticizer and lubricant, gelatinize the starch in the sealed space in the extruder, and then melt with synthetic resin. A biodegradable resin composition obtained by kneading, wherein the starch content is 1 to 60% by weight of the total amount of biodegradable resin, and the content of degradable synthetic resin composed of aliphatic copolyester, ethylene-vinyl alcohol copolymer, and ethylene-vinylacetate copolymer It is composed of 40 to 99% by weight of the total amount of the total biodegradable resin It is a novel invention regarding the biodegradable resin composition and its manufacturing method.

Description

Biodegradable Resin Compositions and Manufacturing Methods Thereof

The present invention relates to a biodegradable resin that is easily decomposed by microorganisms present in the soil upon disposal after use, and relates to a biodegradable resin composition composed of natural materials and synthetic resins and which does not cause environmental pollution, and a method of manufacturing the same.

Synthetic resin, a petrochemical product, has been widely used for various purposes due to its excellent physical properties despite its short history. However, as the problem of environmental pollution caused by waste plastics becomes more serious, the development of degradable resins has been actively made.

When the decomposable resin is classified according to its decomposition mechanism, it is a photodegradable resin decomposed by ultraviolet rays of sunlight, biodegradable resin decomposed by microorganisms present in the soil, and starch which is a natural substance in non-degradable resins such as polyethylene and polypropylene. It can be divided into biodegradable resins filled with biodegradable raw materials. Since the photodegradable resin decomposes only when it is exposed to sunlight, there is a defect that cannot be decomposed in the environment in which it is embedded in the soil and blocked, and the biodegradable resin contributes a lot to the complete decomposition and does not cause environmental pollution. There is an expensive disadvantage, the biodegradable resin is decomposed only biodegradable raw material filled with starch, etc., the remaining non-degradable resin is not decomposed but remains in the soil in small pieces, rather there is a waste of secondary pollution. The present invention aims to obtain biodegradable resins that are completely decomposed by microorganisms in the soil and thus do not cause any environmental pollution, and are significantly inexpensive compared to conventional biodegradable resins.

The present invention is a mixture of natural materials and synthetic resin, starch as a natural material, polyester ethylene-vinyl alcohol copolymer and ethylene-vinylacetate copolymer as a synthetic resin, additives such as plasticizers, lubricants such as processability enhancers and water It relates to a method for producing a biodegradable resin by training, extrusion at high temperature, high pressure.

Starch used in the present invention is used alone or in mixture of two or more kinds extracted from corn, potatoes, rice, sweet potatoes, etc., characterized in that it contains 1 to 60% by weight based on the total amount of biodegradable resin composition, polyester Two types of aliphatic copolyester (I) and aliphatic copolyester (II) are mixed and used, and 40 to 70% by weight of the total amount of biodegradable resin composition is contained.

The constitution of the aliphatic copolyester (I) used in the present invention is (A): The constitution of the acid component residues is composed of 40 to 90 mol% of succinic acid residues and 10 to 60 mol% of adipic acid residues, ( B): The diol residue consists of a 1, 4- butanediol residue and (C): The compound residue which has a trifunctional or more than trifunctional polyfunctional is comprised by the ratio of 0.01-1 mol%. (However, in the case where component C is an acid residue having a trifunctional or higher polyfunctionality, component C is represented based on component A, and in the case of an alcohol residue having a trifunctional or higher polyfunctionality, component C is represented based on component B.)

Moreover, the structure of the aliphatic copolyester (II) used by this invention is (D): the phenylene residue which the structure of an acid component residue consists of solely or two or more types in terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl isophthalate. Is 30 to 70 mol%, succinic acid, adipic acid, sebacic acid, azelaic acid is composed of 30 to 70 mol% of aliphatic dicarboxylic acid residues alone or two or more, and (E): diol residue is ethylene glycol , 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol alone or two or more kinds, (F): compound having a trifunctional or more than trifunctional The residue consists of 0.1 to 3 mol% of ratio. (However, when the component F is an acid residue having a trifunctional or higher polyfunctionality, the component F is represented based on the component D. When the component F is an alcohol residue having a trifunctional or higher polyfunctionality, the component F is represented based on the component E.)

In the present invention, the method for preparing the aliphatic copolyester (I) and the aliphatic copolyester (II) is a monomer component is introduced into a container capable of heating and stirring together with a catalyst and esterified or transesterified at a temperature of 220 ° C. or less. Then, the condensation polymerization reaction is carried out at a high temperature of 240 ° C. or higher and 1 mmHg or lower and high vacuum. At this time, as the condensation polymerization catalyst, a tin compound system or a titanium compound system is effective. Examples of the tin compound include tin oxides such as tin oxide and tin oxide, halogen tin such as tin chloride, tin tin, and sulfide tin, monobutyl tin oxide, dibutyl tin oxide, and monobutyl oxide. Organic tin compounds such as hydroxytin, dibutyltin dichloride, tetraphenyltin, and tetrabutyltin are included, and titanium-based compounds include tetrabutyl titanate, tetramethyl titanate, tetraisopropyl titanate, and tetra (2- Ethylhexyl) tenate and the like.

The biodegradable resin composition according to the present invention is a mixture of aliphatic copolyester (I) and aliphatic copolyester (II), starch, ethylene-vinyl alcohol copolymer and ethylene-butyl acetate copolymer prepared according to the above. In addition, it is also characterized by adding a plasticizer, a lubricant and the like for improving workability.

As a plasticizer, water, glycerin, ethylene diglycol, polyethylene glycol, 1,4-butanediol, etc. may be used alone or in combination of two or more thereof.As a lubricant, triglycerol monostearate, triglycerol distearate, triglycerol tristea The rates are used alone or in combination. The amount of plasticizer added is 10 to 50% by weight relative to starch, and 0.5 to 10% by weight relative to the total biodegradable resin.

In addition, the ethylene-vinyl alcohol copolymer mixed with aliphatic copolyesters (I) and (II) is a high melting point compound having an ethylene content of not more than 44 mol%, and has a melt index of 6 to 15 g / min. The amount of the biodegradable resin composition is 5 to 25% by weight, and the content of the vinyl acetate ethylene-vinyl acetate copolymer is 2 to 20 mol%, and the content is 5 to 25% by weight of the total biodegradable resin composition.

The biodegradable resin production method according to the present invention is melted and extruded by adding heat by adding the composition while supplying sufficient water to gelatinize the starch in a closed space in the twin screw extruder. The water content of the resin discharged through the die during extrusion is adjusted to the amount of water to be 10 to 30% of the total biodegradable resin. The temperature in the barrel is 90 to 230 ° C, the rotational speed (RPM) of the screw is 80 to 150, and the torque is melted and mixed under the conditions of 40 to 60 to produce a biodegradable resin.

Biodegradability of the prepared biodegradable resin was evaluated in a film state by the compost method. Compost composition was prepared as shown in Table 1, and put into a compose reaction tube with a sample and the weight loss of the sample was measured for 10 weeks while adjusting to the conditions as shown in Table 2.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely based on an Example.

1. Composition of aliphatic copolyester (I): 1360 g (15.092 mol) of 1,4-butanediol in a reactor with a stirrer and a condenser, 1173,9 g (9.994 mol) succinic acid, 242.6 g (1.660 mol) adipic acid , 4 g (0.033 mole) of trimethylol ethane and 1.02 g (0.003 mole) of tetrabutyl titanate were added thereto, and the temperature in the reactor was raised from room temperature to 120 ° C. over 40 minutes, and the temperature was raised to 210 ° C. over 120 minutes with stirring. I was. At this time, the generated side reaction water was completely discharged through the condenser. Subsequently, the pressure in the tube was gradually reduced to 0.5 mmHg over 45 minutes, and the stirring reaction was performed for 10 minutes while the temperature of the tube was raised to 245 ° C. Then, the stirring was stopped and nitrogen was introduced into the tube to pressurize and discharge the polymer. A high molecular weight aliphatic copolyester (I) is obtained.

2. Composition of aliphatic copolyester (II): 1187 g (19.24 mol) of 1,4-butanediol, 649 g (4,441 mol) of adipic acid, 862 g (4.440 mol) of dimethyl terephthalate and penta in a reactor with a stirrer and a condenser 5 g (0.037 mol) of erythritol was added, and 1.0 g of manganese acetate was added as a catalyst to raise the temperature in the reactor to 120 ° C. over 30 minutes from normal temperature, and to raise the temperature to 220 ° C. over 120 minutes while stirring. At this time, the side reaction product, methanol and water, were completely discharged through the condenser.

Subsequently, 1.5 g of tetrabutoxy titanate as a catalyst and 0.4 g of phosphoric acid as a heat stabilizer were added thereto, and the pressure in the tube was gradually reduced to 0.5 mmHg over 45 minutes, and the reaction was stirred for 180 minutes while the temperature was raised to 245 ° C. After proceeding, the stirring was stopped and nitrogen was introduced into the tube to pressurize and discharge the polymer to obtain aliphatic copolyester (II).

3. Composition of aliphatic polymer polyester (III): 1187 g (19.24 mol) of 1,4-butanediol, 259.5 g (1.776 mol) of adipic acid, 1379.4 g (7.105 mol) of adipic acid in a reactor equipped with a stirrer and a condenser And 5 g (0.037 mol) of pentaerythritol were added, and 1.0 g of manganese acetate was added as a catalyst to raise the temperature in the reactor to 120 ° C. over 30 minutes from normal temperature, and the reaction was heated to 220 ° C. over 120 minutes with stirring.

Methanol and water produced at this time were completely discharged through a condenser. Subsequently, 1.5 g of tetrabutoxy titanate as a catalyst and 0.4 g of phosphoric acid as a heat stabilizer were added thereto, and the pressure was gradually reduced to 0.5 mmHg over 45 minutes, and the reaction temperature was stirred for 180 minutes while the temperature was raised to 245 ° C. After stirring, the stirring was stopped and nitrogen was introduced into the tube to pressurize and discharge the polymer to obtain aliphatic copolyester (II).

Example 1

20 parts by weight of corn starch, 25 parts by weight of the aliphatic copolyester (I) and 25 parts by weight of aliphatic copolyester (II) with synthetic resin, 20 parts by weight of ethylene-vinyl alcohol copolymer (44 mol% ethylene), ethylene- 2 parts by weight of vinyl acetate copolymer (20 mol% of vinyl acetate) and triglycerol monostearate as a lubricant were mixed, and 4 parts by weight of glycerin and 10 to 40% of water were added to the starch as a plasticizer. After melting and mixing to prepare a biodegradable resin pellet, the blown film having a thickness of 40 ㎛ was evaluated for physical properties, the results are shown in Table 3.

※ Extrusion condition

① screw speed: 80

② Torque: 40

③ Barrel Temperature: 110 ℃ / 150 ℃ / 190 ℃ / 210 ℃ / 180 ℃ / 160 ℃

Comparative Example 1

Except for using 43 parts by weight of the aliphatic copolyester (I) and 7 parts by weight of aliphatic copolyester (II) in the synthetic resin is the same as in Example 1 and the results are shown in Table 3.

Comparative Example 2

Except for using 17 parts by weight of the aliphatic copolyester (I) and 33 parts by weight of aliphatic copolyester (II) in the synthetic resin is the same as in Example 1 and the results are shown in Table 3.

Comparative Example 3

35.5 parts by weight of the aliphatic copolyester (I), 35.5 parts by weight of aliphatic copolyester (II) in the synthetic resin, 6 parts by weight of ethylene-vinyl alcohol copolymer (44 mol% ethylene), ethylene-vinylacetate air Except for using 3 parts by weight of the copolymer (vinyl acetate content 20 mol%) is the same as in Example 1 and the results are shown in Table 3.

[Comparative Example 4]

Except that 5 parts by weight of ethylene-vinyl alcohol copolymer (44 mol% ethylene) and 25 parts by weight of ethylene-vinylacetate copolymer (20 mol% vinyl acetate) were used in the synthetic resin. Table 3 is as follows.

[Comparative Example 5]

Except that 25 parts by weight of the ethylene-vinyl alcohol copolymer (44 mol% ethylene) and 5 parts by weight of the ethylene-vinylacetate copolymer (20 mol% vinyl acetate) in the synthetic resin are the same as in Example 1 Table 3 is as follows.

Comparative Example 6

61 parts by weight of starch, 13 parts by weight of the aliphatic copolymerized polyester (I) in synthetic resin, 13 parts by weight of aliphatic copolymerized polyester (II), 8 parts by weight of ethylene-vinyl alcohol copolymer (44 mol% of ethylene), Except for using 5 parts by weight of the ethylene-vinylacetate copolymer (vinyl acetate content 20 mol%) is the same as in Example 1 and the results are shown in Table 3.

Comparative Example 7

Except that the aliphatic copolyester (II) instead of the aliphatic copolyester (II) in the synthetic resin is the same as in Example 1 and the results are shown in Table 3.

Claims (6)

A biodegradable resin composition obtained by mixing starch, which is a natural substance, with degradable synthetic resin, adding plasticizer and lubricant, gelatinizing starch in an enclosed space in an extruder, and then melting and kneading with synthetic resin. It is 1 to 60% by weight of the total amount of the resin, and the content of the degradable synthetic resin composed of aliphatic copolyester, ethylene-vinyl alcohol copolymer, and ethylene-vinylacetate copolymer is 40 to 99% by weight of the total amount of biodegradable resin. Biodegradable resin composition characterized in that. The biodegradable resin composition according to claim 1, wherein the content of aliphatic copolyester is 40 to 70% by weight of the total amount of the biodegradable resin. The biodegradable resin composition according to claim 1, wherein the content of the ethylene-vinyl alcohol copolymer is 5 to 25% by weight of the total amount of the biodegradable resin. The biodegradable resin composition according to claim 1, wherein the content of the ethylene-vinylacetate copolymer is 5 to 25% by weight of the total amount of the biodegradable resin. The aliphatic copolyester according to claim 2, wherein the acidic moiety comprises 40 to 90 mole% of succinic acid residue and 10 to 60 mole% of adipic acid residue, and the diol residue is 1,4-butanediol moiety. Aliphatic co-polyester (I) consisting of a compound residue having a trifunctional or more than trifunctional polyfunctional at a ratio of 0.01 to 1 mol% and an acid component residue is composed solely or in terephthalic acid, dimethyl terephthalate and dimethyl isophthalate. 30 to 70 mol% of phenylene residues composed of two or more species, and 30 to 70 mol% of aliphatic dicarboxylic acid residues composed of two or more of succinic acid, adipic acid, sebacic acid, and azelaic acid. Is composed of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol alone or two or more kinds, and the compound residue having a trifunctional or higher polyfunctionality Aliphatic composed of 0.1 to 1 mol% A biodegradable resin composition comprising a mixture of copolyester (II). In the twinscrew extruder, plasticizer is separately injected while decomposing synthetic resin, starch, and lubricant composed of the above-mentioned aliphatic copolyester, ethylene-vinyl alcohol copolymer and ethylene-vinylacetate copolymer, to gelatinize the starch in an enclosed space, A method for producing a biodegradable resin composition, characterized in that the melt kneading under the conditions of the temperature of 90 ~ 230 ℃, the rotational speed of the screw (rpm) 80 ~ 150, torque 40 ~ 60.