KR100523480B1 - Biodegradable Resin Composition - Google Patents

Abstract

The present invention relates to a biodegradable resin which is a material such as a plastic film such as a disposable packaging material, and mechanical properties and heat adhesion during processing into a molded product such as a film without degrading degradability, which is inherent to the biodegradable resin, The purpose is to provide a biodegradable resin having excellent properties.

That is, the present invention blends biodegradable aliphatic polyester with excellent mechanical properties with starch-based decomposable resins to compensate for vulnerabilities of starch, morphological stability, mechanical properties, and water resistance, and blends starch-based biodegradable resins to lower manufacturing costs. When blending resins, epoxy resins for improving processability and resins for improving thermal adhesion are added to the resins to provide compatibility between resins, resulting in excellent morphological stability and mechanical properties as well as water composting process. It simply provides a biodegradable resin that continues to decompose to become a low molecular weight material that the microorganisms can ingest and ultimately be completely decomposed by the microorganism into gas, water or biomass.

Description

Biodegradable Resin Composition

The present invention relates to a biodegradable resin composition having excellent mechanical properties and thermal adhesiveness, and more particularly, to an epoxy-based compound which improves the compatibility of a resin when blending a biodegradable aliphatic polyester with starch and improves thermal adhesiveness. The present invention relates to a biodegradable resin composition which is excellent in processability and heat adhesiveness during molding, and has no mechanical property deterioration when forming into a film, and is completely decomposed by microorganisms in soil by adding a polymer to make a polymer.

Existing general-purpose plastics are widely used in daily life because of excellent mechanical properties, chemical resistance, durability, etc., but have a disadvantage in that they cannot be reduced to nature upon disposal after use. Disposable packaging materials, which are rapidly increasing in demand, are often left unused because they are not consumed smoothly even though they are consumed. Agricultural films are difficult to recover completely and are buried in the soil, causing many obstacles to crop growth. As environmental pollution caused by plastic wastes has become a social problem, there is a growing interest in degradable resins that are automatically decomposed when used after a certain period of time for environmental protection.

These types of degradable resins are classified into biodegradable resins decomposed by microorganisms present in the soil and photodegradable resins in which sunlight is decomposed by ultraviolet rays. Photodegradable resins developed to date have the disadvantage that they do not receive light when they are buried in soil. Biodegradable resins include natural starch, polyhydroxyalkanoate resin synthesized in vivo by microorganisms, polycaprolactone synthetic synthetic biodegradable resins, and polylactide obtained by chemical synthesis of raw materials produced by microorganisms. Etc. are known.

However, these resins are excellent in degradability, but when used alone, they have many difficulties in commercialization because of poor physical properties and high price. In order to improve such a problem, a method of improving the shape stability and physical properties of a polymer by mixing starch whose crystal structure is broken with an ethylene / acrylic acid copolymer or an ethylene / vinyl alcohol copolymer is mixed with an aliphatic polyester. Although mentioned in 5422387, the biodegradability is good when manufacturing a biodegradable resin in this way, but it is limited in its use due to the lack of physical properties and poor thermal adhesiveness when processed into molded products.

The present invention has been made to solve the above problems, to provide a biodegradable resin composition excellent in mechanical properties and heat adhesiveness when processing into a molded article such as film without degrading the intrinsic properties of the biodegradable resin. It is for the purpose.

That is, the present invention blends biodegradable aliphatic polyester with excellent mechanical properties with starch-based decomposable resins to compensate for vulnerabilities of starch, morphological stability, mechanical properties, and water resistance, while blending starch-based biodegradable resins to lower manufacturing costs. By blending resins, epoxy resins that improve the processability by providing compatibility between resins and resins that improve heat adhesion are not only excellent in form stability and mechanical properties but also in composting process of urban waste. It is an object of the present invention to provide a biodegradable resin composition which, if present, continues to be decomposed to become a low molecular weight substance that microorganisms can ingest and ultimately be completely decomposed by the microorganism into gas, water or biomass.

The present invention is a starch-based biodegradable resin 10 to 50% by weight, 0.1 to 5% by weight of the epoxy compound represented by the following formula (3), 1 to 10% by weight plasticizer and 0.001 to the amide compound represented by the formula (2) It relates to a biodegradable resin composition comprising 1% by weight, and the residual amount of aliphatic polyester represented by the following formula (1).

[Formula 1]

However, R1

or

R2 is

or

or

m and n are integers

[Formula 2]

However, R3 : C2-C30 acryl group, aroyl group, alkyl group, or phenyl group

[Formula 3]

R4 : Methylene, vinyl, aryl, or propenyl group R 5 as alkenyl group : Alkyl group as methyl, ethyl, 1-propyl, or 2-propyl group

Hereinafter, the present invention will be described in detail.

In the present invention, the aliphatic polyester copolymer of Formula 1 has a high molecular weight property, and thus polycaprolactone, polycondensation catalyst and phosphorus compound in the oligomer obtained through the process of directly esterifying aliphatic dicarboxylic acid and aliphatic glycol and esterification. Is prepared by the process of polycondensation polymerization under vacuum of 1 mmHg or higher at 220 ° C. or higher, and has a weight average molecular weight of 100,000 or higher. The molecular weight of the aliphatic polyester copolymer is determined by using a biodegradable resin sheet or film. Or greatly influences the processability and the physical properties of the manufactured workpieces during the production of foam moldings, and when the molecular weight is low, the mechanical properties of the workpieces are poor.

In addition, the aliphatic polyester copolymer of the general formula (1) used in the present invention is advantageous when forming the biodegradable resin composition when the melting point is 60 ℃ or more, if the melting point is less than 60 ℃, workability during molding processing such as film production becomes poor. .

The weight percent of the aliphatic polyester of Formula 1 is the remaining amount after adding starch-based decomposable resin, amide particle material of Formula 2, epoxy compound of Formula 3, and plasticizer to the total weight of biodegradable resin composition. It is composed. In this case, the mechanical properties, processability, etc. of the biodegradable resin composition is advantageous. On the other hand, the starch-based decomposable resin is 10 to 50% by weight relative to the biodegradable resin composition which is the final product of the present invention is advantageous to the processability (the weight percentages mentioned below are all based on the total biodegradable resin composition.) . If the starch is contained less than 10%, there is a problem in the practicality due to the lack of heat adhesiveness and high manufacturing price of the entire biodegradable resin, if the content exceeds 50% by weight of the form stability and mechanical properties of the biodegradable resin composition Etc. becomes poor.

The amide particle of Formula 2 should use 0.001-1% by weight of the biodegradable resin composition. If less than 0.001% by weight is added, the adhesion is poor during thermal bonding after film forming. Mechanical properties of the molded film are lowered.

Epoxy-based compound of Formula 3 uses 0.1-5% by weight, the use of less than 0.1% by weight is insufficient compatibility between resins due to poor processability and mechanical properties of the molded film, when using more than 5% by weight of the molded film It is disadvantageous because the improvement in processability and mechanical properties is insignificant and causes a price increase.

The dicarboxylic acid component or derivative thereof used in the preparation of the aliphatic polyester copolymer of the formula (1) used in the present invention includes lower grades such as succinic acid, adipic acid, sublinic acid, sebacic acid, dodecanoic acid, succinic anhydride, adipic acid, or dimethyl ester. Alcohol esters and the like are used and it is also possible to use such materials as comonomers. As the glycol component, ethylene glycol, 1,4 butanediol, 1,6 hexanediol, decamethylene glycol, neopentyl glycol, 1,4 cyclohexane methanol, etc. may be used, with one component as a main component and the other component as a comonomer It is also possible to use. The molar ratio of the aliphatic dicarboxylic acid component and the aliphatic diol component of the general formula (1) of the present invention is in a ratio of 1: 1 to 1: 2 (more preferably, in a ratio of 1: 1.2 to 1: 1.7). It is advantageous in terms of physical properties and color tone.

In addition, the polyfunctional compound having three or more terminal hydroxyl groups or terminal carboxyl groups in the preparation of the aliphatic polyester of Formula 1 is trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate It is possible to use a small amount of, trimellitic acid, trimellitic anhydride, benzenetetracarboxylic acid, benzenetetracarboxylic acid anhydride and the like. At this time, the molecular weight of the polymer produced by the copolymerization reaction of the compound having a trifunctional or higher polyfunctionality is rapidly increased, and thus the melt viscosity and the melt strength are greatly improved. In the case of using a compound having a polyfunctionality, it is preferable to copolymerize the acid component within the range of 0.01 to 1 mol%, but when the compound having a trifunctional or higher polyfunctional compound is more than 1 mol%, the reaction is very high. It can proceed in a short time to obtain a high molecular weight polymer, but the degree of crosslinking is rapidly increased to form a gel, resulting in an unsuitable polymer state for molding.

In the biodegradable resin composition of the present invention, when the aliphatic polyester copolymer of Chemical Formula 1 is prepared, the temperature of the esterification process may be performed at 220 ° C. or lower to minimize the generation of by-products and thermal decomposition. As the polycondensation catalyst used in the present invention, a tin compound system or a titanium compound system is effective, and as a tin compound, tin oxides such as tin oxide, tin oxide, tin oxide, tin chloride, tin sulfide, etc. Organic tin compounds such as halogen tin, monobutyl tin oxide, dibutyl tin oxide, monobutyl hydroxy tin oxide, dibutyl tin dichloride, tetraphenyl tin and tetrabutyl tin are examples of the titanium compound. Nate, tetramethyl titanate, tetraisopropyl titanate, tetra (2-ethylhexyl) titanate and the like can be used. The addition amount of the polymerization catalyst used in the present invention is suitably used within the range of 0.01-0.1 mol% based on the acid component. At this time, when the amount of the catalyst used exceeds 0.1 mol%, the discoloration of the polymer is severely generated, and when using less than 0.01 mol%, the reaction rate is slowed.

In the present invention, as a heat stabilizer, a phosphorus compound may be used, and phosphoric acid, monomethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, monophenyl phosphate, triphenyl phosphate and derivatives thereof, phosphorous acid, triphenyl phosphite, trimethyl Phosphorous acid and its derivatives, Iganox 1010, Iganox 1222, Phenylphosphonic acid, and the like, phosphoric acid, trimethyl phosphoric acid, triphenyl phosphoric acid and the like are excellent in effect. The amount of the phosphorus compound as a heat stabilizer is 1.0 × 10 ^-7 for the oligomer obtained by esterification or transesterification - 1.0 × 10 ^-6 mol / g oligomer (more preferably from ^{0.5 × 10 -6 - 1.5 × 10} -6 Mole / gram oligomer).

In order to obtain a high molecular weight aliphatic copolyester, it has to be polycondensed under high vacuum conditions and the reaction temperature is 240-260 ° C. If the reaction temperature is less than 240 ℃ the polycondensation reaction rate is very slow to obtain a polymer of the desired high molecular weight, it is difficult to obtain a polymer of the desired high molecular weight, and if it exceeds 260 ℃ rather than the thermal decomposition is worse due to poor physical properties and color tone of the obtained polymer.

In the present invention, the method for preparing starch-based biodegradable material is an epoxy-based polymer material for improving compatibility of starch and resin, which is a natural degradable substance, to an aliphatic copolyester which is a synthetic degradable material, and a plasticizer and heat adhesiveness to improve processability. It is used to knead in twin extruders by adding amide-based particulate matter to improve the temperature. At this time, any of starch extracted from potato, rice, corn, etc. may be used. It is advantageous in terms of processability, physical properties and cost to be included within the weight percent range.

Plasticizers to plasticize starch include water, glycerin, glycol glycosides, sorbitol, glycerol monostearate, triglycerol monostearate, hexaglycerol monopalmitate, urea, phenol, resorcinol, hydrokinen, phytogalol, cyclohexahexa Knoll, benzyl alcohol, sodium benzoate, sodium phthalate, glycoic acid and the like are used, but glycerin, urea, water and the like are preferably mixed in an appropriate amount.

Glycerin, urea, and water are suitable to contain 1 to 10% by weight, if less than 1% by weight is poor processability, and when it exceeds 10% by weight, the physical properties are bad.

Claims (1)

Starch 10 to 50% by weight, 0.1 to 5% by weight of the epoxy compound represented by the following formula (3), 1 to 10% by weight of the plasticizer, 0.001 to 1% by weight of the amide compound represented by the formula (2), and represented by the formula (1) Biodegradable resin composition comprising a residual amount of aliphatic polyester. [Formula 1] However, R1 or R2 is or or m and n are integers [Formula 2] However, R3 : C2-C30 acryl group, aroyl group, alkyl group, or phenyl group [Formula 3] R4 : Methylene, vinyl, aryl or propenyl group as alkenyl group, R 5 : Alkyl group is methyl, ethyl, 1-propyl, or 2-propyl group