KR100503763B1 - Biodecomposable resin composition - Google Patents

Abstract

The present invention relates to a biodegradable resin composition that has been actively conducted in recent years for the purpose of environmental protection by waste in the plastics field, and provides a method for producing a biodegradable resin having excellent processability and heat adhesiveness as compared to the conventional one. Its purpose is to.

The present invention relates to a biodegradable resin composition composed of starch, a compatibilizer, a plasticizer, an amide particle material of Formula 2, and other additives to an aliphatic polyester represented by Formula 1 below, and in particular, has excellent processability, thermal adhesiveness, and mechanical properties. In addition, it has the advantage of being almost completely biodegradable and inexpensive at disposal.

[Formula 1]

─ [OC─R ₁ ─COO─R ₂ ─O] _m ─ [CO─CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ─O] _n ─

Provided that R ₁ is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ──

R2 is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ──

m and n are integers

[Formula 2]

R-CONH ₂

Provided that R is acy1, aroy1, alky1 or pheny1

Description

Biodegradable Resin Composition {BIODECOMPOSABLE RESIN COMPOSITION}

The present invention relates to a composition of a biodegradable resin excellent in processability and heat adhesiveness, and more specifically, to a metal-based material which improves processability when blending biodegradable aliphatic polyester with starch and a polymer material that improves heat adhesion. The present invention relates to a method for producing a biodegradable resin which is excellent in processability and thermal adhesion during molding and is completely decomposed by microorganisms in soil.

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 when disposed after use. Disposable packaging materials, which are rapidly increasing in demand, are often left untouched because they are not easily recovered despite high consumption, and 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, development of degradable resins that automatically decompose upon disposal after a certain period of time has been actively conducted in order to protect the environment.

These types of degradable resins are classified into biodegradable resins decomposed by microorganisms present in the soil and photodegradable resins decomposed by ultraviolet rays of sunlight. 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 polymer-based biodegradable resin, and polylactide obtained by chemical synthesis of raw materials produced by microorganisms. Etc. are known.

However, these resins are difficult to commercialize because they are excellent in degradability but are vulnerable and expensive when used alone. In order to improve these problems, a method of improving the affinity with starch by introducing polyethylene glycol into aliphatic polyester and improving the morphological stability and physical properties of the polymer by using starch and polysaccharide polymer that has destroyed crystal structure Although the method is mentioned in Japanese Patent Laid-Open No. 7-330954 and European Patent No. 409781, the biodegradability is good when manufacturing the biodegradable resin by this method, but when it is processed into a molded product, the physical properties are poor and the thermal adhesiveness is poor. Restricted

The present invention has been made to solve the above problems, and provides a biodegradable resin having excellent processability, heat adhesion and physical properties when processing into molded products such as films without degrading degradability, which is inherent to the biodegradable resin. It is for that purpose.

According to the present invention, after preparing an aliphatic polyester having a structural formula as shown in Chemical Formula 1, a starch and compatibilizer, which is a natural degradable substance, and a plasticizer and a metallic particle material for improving processability, are added, and the heat adhesiveness is improved. The present invention relates to a biodegradable resin composition obtained by adding an amide particle material.

[Formula 1]

─ [OC─R ₁ ─COO─R ₂ ─O] _m ─ [CO─CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ─O] _n ─

Provided that R ₁ is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ──

R2 is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ──

m and n are integers

[Formula 2]

R-CONH ₂

(Where R is an acy1 group, aroy1 group, alky1 group or pheny1 group having 2-30 carbon atoms)

In the present invention, the aliphatic polyester copolymer of Formula 1 has a high molecular weight property, and a polycaprolactone, a polycondensation catalyst, and an oligomer obtained through the esterification process and esterification of aliphatic dicarboxylic acid and aliphatic glycol, and It is prepared by adding a phosphorus compound and subjecting it to condensation polymerization under a vacuum of 220C or higher and 1mmHg or lower. In this case, the aliphatic polyester copolymer needs to have a weight average molecular weight of 100,000 or more, and the size of the molecular weight greatly influences the processability or physical properties of the manufactured workpiece when the sheet, film, or foam molding is manufactured. Mechanical properties are poor.

In addition, the aliphatic polyester copolymer of the general formula (1) used in the present invention should have a melting point of 60 ℃ or more, if the melting point is less than 60 ℃ processability during the molding process, such as film production is poor. And it is advantageous to use the aliphatic polyester of the general formula (1) 60 to 95% by weight based on the total degradable resin composition mechanical properties, processability and the like of the degradable resin composition. When the amount of the aliphatic polyester of Formula 1 is less than 60% by weight relative to the total degradable resin composition, the form stability and mechanical properties of the decomposable resin composition are poor, and when used in excess of 95% by weight, the thermal properties are poor.

Dicarboxylic acid components or derivatives thereof in the preparation of the aliphatic polyester of Chemical Formula 1 include lower alcohol esters such as succinic acid, adipic acid, severic acid, sebacic acid, dodecanoic acid, succinic anhydride, adipic anhydride or dimethyl ester, and the like. It is also possible to use these as comonomers. As the glycol component, ethylene glycol 1.4 butanediol, 1.6 hexanediol, decamethylene glycol, neopentyl glycol, 1.4 cyclohexane methanol, and the like may be used. It is also possible to use one component as a main component and the other component as a comonomer. At this time, the molar ratio of the aliphatic carboxylic acid component and the aliphatic diol component is preferably reacted at a ratio of 1: 1 to 1: 2, and more preferably, at a ratio of 1: 1.2 to 1: 1.7, the reaction and Advantageous in terms of physical properties and color tone. In the aliphatic polyester used in the present invention, trimethylolpropane, trimethylol ethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanate as a polyfunctional compound having three or more terminal hydroxyl groups or terminal carboxyl groups. Small amounts of anurate, trimellitic acid, trimellitic anhydride, benzenetetracarboxylic acid, benzenetetracarboxylic acid anhydride and the like can be used. In this case, the molecular weight of the polymer produced by the copolymerization reaction of a compound having trifunctional or higher polyfunctionality rapidly increases, and accordingly, the melt viscosity and the melt strength are greatly improved. When using the compound which has polyfunctionality, it is good to carry out copolymerization reaction in 0.01-1 mol% with respect to an acid component. In the case of copolymerizing a compound having a trifunctional or higher polyfunctionality in a range of more than 1 mole% or more, the reaction proceeds in a very short time to obtain a high molecular weight polymer, but the crosslinking degree rapidly increases to form a gel to form the molding process. An unsuitable polymer state is obtained.

In addition, when the aliphatic polyester copolymer of Formula 1 is prepared, the esterification reaction conditions are suitable for minimizing by-product generation and pyrolysis. As the condensation polymerization catalyst usable in the present invention, a tin compound system or a titanium compound system is effective, and tin compounds include tin oxides such as tin oxide and tin oxide, tin chloride, tin chloride, and tin sulfide. Organic tin compounds such as halogen tin, monobutyl tin oxide, dibutyl tin oxide, monobutyl hydroxy oxide tin, dibutyl tin dichloride, tetraphenyl tin, and tetrabutyl tin. Titanate, 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 to 0.1 mol% based on the acid component. When the amount of the catalyst used exceeds 0.1 mol%, discoloration of the polymer is severely generated, and when the amount of the catalyst is used less than 0.01 mol%, the reaction rate is slowed.

As the heat stabilizer used in the present invention, a phosphorus compound may be used. For example, phosphoric acid, monomethyl phosphoric acid, trimethyl phosphoric acid, tributyl phosphoric acid, trioctyl phosphoric acid, monophenyl phosphoric acid, triphenyl phosphoric acid and its derivatives, phosphorous acid, Triphenylphosphoric acid, trimethylphosphoric acid and derivatives thereof, Iganox 1010, Iganox 1222, phenylphosphonic acid and the like, among which 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 X 10 ^-7 for the oligomer obtained by esterification or transesterification - 1.0 X 10 ^-6 moles / g oligomer (more preferably from ^{0.5 X 10 -6 - 1.5 X 10} -6 Mole / gram oligomer).

In addition, in order to obtain a high molecular weight aliphatic copolyester, polycondensation should be carried out under high vacuum conditions, and the reaction temperature is 240 to 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, if the temperature exceeds 260 ℃ rather than the thermal decomposition is worse due to poor physical properties and color tone.

Meanwhile, in the present invention, starch and synthetic resins, which are naturally degradable substances, and aramid-based particle materials for improving plasticity and heat adhesion are added to the aliphatic copolymer polyester prepared by the above method.

As the starch, any of starches extracted from potatoes, rice, corn, etc. may be used, and the amount of starch used within 10 to 50% by weight of the total weight of the biodegradable resin is advantageous in terms of processability, physical properties, and cost.

In addition, in the present invention, as a compatibilizer for improving the compatibility of starch and aliphatic copolymer polyester, alkylene / vinyl ester, ethylene / vinyl acetate, ethylene / vinyl alcohol, alkylene / acrylate or methacrylate , Ethylene / acrylic acid type, ethylene / ethyl acrylate type, ethylene / methyl acrylate type, styrene / acrylonitrile type, acryric acid ester / acrylonitrile type, acrylamide / acrylonitrile type, amide- Block copolymers of ethers, block copolymers of urethane ethers, compounds of urethane esters, and the like can be used, among which compounds of ethylene / vinyl acetate type are most advantageous in terms of compatibility. The amount of such compatibilizer used is preferably within the range of 1 to 10% by weight of the total amount of total biodegradable resin, in terms of compatibility, processability and physical properties.

And plasticizers for improving processability include water, glycerin, glycol glycosides, sorbitol, glycerol monostearate, triglycerol monostearate, hexaglycerol monopalmitate, urea, phenol, resorcinol, hydrokinen, phytogalol, Cyclohexanol, benzyl alcohol, sodium benzoate, sodium phthalate, glycoic acid and the like are used, and it is common to use glycerin, urea and water in an appropriate amount. The amount of glycerin, urea and water is 1-10% of the total amount of total biodegradable resin, respectively, and the use of less than 1% is poor in processability, and the use of more than 1% is poor in mechanical properties.

In addition, the amide particle of Formula 2 uses 0.001 to 1% by weight of the total amount of decomposable resin, when less than 0.001% by weight of the thermal film of the molded film is poor, when using more than 1% by weight of the molded film Mechanical properties are lowered.

In the present invention, in order to improve the processability when manufacturing the biodegradable resin as a film or the like, CaO, Al ₂ O ₃ , Fe ₂ O ₃ , CaCO ₃ , MgCO ₃ , SiO ₂ , Na ₂ O, etc. It can be used, the amount of use is appropriately 0.001 to 0.1% by weight of the total amount of decomposable resin. When using less than 0.001% by weight is poor workability, when using more than 0.1% by weight, the physical properties of the molded article is lowered.

The composition of the biodegradable resin having the composition described above is a twin screw extruder having a diameter of 30 mm and an L / D of 25. The extruder barrel has a temperature of 60-210 ° C., a screw rotational speed of 50-200, The torque can be extruded under the conditions of 35 to 70 kg / cm 2 to obtain pellets of the biodegradable resin composition.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The molecular weight measured in Examples was measured using gel permeation chromatography, melting point was analyzed using a differential calorimetry analyzer, and a film for measuring mechanical properties such as tensile strength was prepared using a blow film forming machine manufactured by HAAKE. Tensile strength (kg / cm 2) and elongation at break (%) were measured according to ASTM D-412. And biodegradability was measured according to ASTM G21-70 and the degradability acceleration method (Composting Method). The measurement procedure of ASTM G21-70 is as follows. Place the sample film on an agar solid batch and mix spores of Aspergillus niger, Penicillium funiculosum, Trichoderma SP and Pullularia pullulans After a certain amount of dispersion, the fungus grew after 2-4 weeks. If the sample area was less than 10% of the sample area, 1, 10-30%, 2, 30-60% was 3, and 60% was 4. On the other hand, the measurement process of the degradation acceleration evaluation method is as follows. The medium was composed as shown in Table 1 to match the composition ratio of waste generated in Korea, and the internal environment was adjusted as shown in Table 2 and maintained for 10 weeks after inserting the sample film. Was evaluated.

TABLE 1

TABLE 2

Hereinafter, an embodiment of the present invention will be described in detail.

Synthesis Example 1

960.4 g (8.133 mole) of succinic acid, 509.3 g (3.485 mole) of adipic acid, 1,338 g (14.525 mole) of 1,4-butanediol, and 4 g (0.033 mole) of trimethylol ethane were added to a reactor equipped with a stirrer and a condenser. The temperature in the reactor was elevated to 210 ° C. over 120 minutes from normal temperature. At this time, the produced side reaction water was completely discharged through a condenser to obtain an esterification reaction product, followed by 200 g of polycaprolactone (Union Carbide, TONE P-787) having a number average molecular weight of 43,000, tetrabutyl titanate as a catalyst. 1.70 g and 0.8 g of phosphoric acid were added as a heat stabilizer, and the pressure in the tube was gradually reduced to 0.5 mmHg over 45 minutes, and the stirring reaction was continued for 150 minutes while the temperature of the tube was raised to 245 ° C. Nitrogen was injected into the tube to pressurize and discharge the polymer to obtain the desired aliphatic copolymer.

Example 1

The aliphatic copolymer polyester 7Kg prepared in Synthesis Example 1 was well mixed with starch 2Kg, ethylene vinyl acetate 200g, glycerin 300g, urea 150g, SiO ₂ 5g, and 50g of the amide compound represented by the formula (2). In case of kneading extrusion at the condition of screw speed 100rpm, torque 65Kg / ㎠ and barrel temperature of extruder 60 ℃ / 130 ℃ / 160 ℃ / 170 ℃ / 170 ℃ / 160 ℃, 200g of water is added by using different inlet for biodegradation. Sex resin pellets were prepared.

The biodegradable pellets prepared in this way were subjected to BLOW-UP RATIO = 4, TAKE-UP SPEED = 15m / min, screw SPEED = 50rpm, barrel temperature 100 ℃ / 145 ℃ / 150 / using HAAKE RHEOCORD 90 blown film processing equipment. A film having a thickness of 40 μm was prepared at 145 ° C., and the results of evaluating the elongation, heat adhesiveness, processability and degradability are shown in Table 1.

Comparative Example 1

The film was prepared in the same manner as in Example 1 except that 1 Kg of aliphatic copolymer polyester, 300 g of starch, and 3 Kg of ethylene vinyl acetate were used in Example 1, and the elongation, heat adhesion, processability and degradability were evaluated. One result is shown in Table 1.

Comparative Example 2

In Example 1, except that 30g of ethylene vinyl acetate and no SiO ₂ and amide compound were used, the film was prepared in the same manner as in Example 1, and the ductility, thermal adhesiveness, processability and degradability were evaluated. Table 1 is as follows.

Comparative Example 3

Except not using glycerin and urea in Example 1 was carried out in the same manner as in Example 1 to prepare a film, the results of the evaluation of the elongation, heat adhesion, processability and degradability are shown in Table 1.

Comparative Example 4

Except not using an amide particle material in Example 1 was carried out in the same manner as in Example 1 to prepare a film, the results of the evaluation of the elongation, heat adhesion, processability and degradability are shown in Table 1.

Comparative Example 5

In Example 1 was prepared in the same manner as in Example 1 except that 500g of amide-based particulate matter and 300g of water was directly mixed with other resin without using any other inlet, elongation, heat adhesion, processability and The results of evaluating the degradability are shown in Table 1.

TABLE 1

Biodegradable resin composition according to the present invention is not only excellent in processability, heat adhesiveness, mechanical properties, but also can be decomposed and consumed by microorganisms as long as water is present at the time of disposal. It is a substance having a low molecular weight of degree and is ultimately completely decomposed into gas, water or biomass by microorganisms, and has an advantage of being inexpensive compared to conventional biodegradable resins.

Claims (2)

50 to 90% by weight, 5 to 45% by weight of starch, 1 to 10% by weight of compatibilizer, 1 to 10% by weight of plasticizer, represented by the following general formula (1) having a weight average molecular weight of 100,000 or more and a melting point of 60 ° C or more 0.001 to 1% by weight of an amide particle material represented by 2 and CaO, Al ₂ O ₃ , Fe ₂ O ₃ , CaCO ₃ , Biodegradable resin composition, characterized in that consisting of 0.001 to 0.1% by weight of at least one metal oxide selected from the group consisting of MgCO _3, SiO _2, Na ₂ O. [Formula 1] ─ [OC─R ₁ ─COO─R ₂ ─O] m─ [CO─CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ─O] n─ Provided that R ₁ is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ── R ₂ is ──CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ ── or ──CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ ── m and n are integers [Formula 2] R-CONH ₂ group, R is acy1 group, aroy1 group, alky1 group, or pheny1 group of 2-30 carbon atoms The biodegradable resin composition according to claim 1, wherein the compatibilizer added for the purpose of improving the compatibility between the starch and the aliphatic polyester is an alkylene / vinylacetate compound.