KR0135211B1 - Degradable resin composition - Google Patents

Abstract

The present invention relates to a biodegradable resin composition which is completely decomposed by microorganisms in the soil after use, and does not cause environmental pollution. More specifically, the present invention relates to a biodegradable starch of 1 to 99% by weight and 10 to polycaprolactone. It is composed of 99 ~ 1% by weight of degradable synthetic resin composed of 75% by weight, 10 ~ 50% by weight of aliphatic polyester, 1 ~ 35% by weight of polyvinyl alcohol and 5 ~ 40% by weight of ethylene-vinyl alcohol. Biodegradable resin, characterized in that it is melted and kneaded after adding 10 to 50% by weight to starch, 1 to 5% by weight of other plasticizers to the total resin composition, and 0.5 to 10% by weight of lubricants to the total resin composition. It relates to a composition.

Description

Degradable Resin Composition

The present invention relates to a biodegradable resin composition which is completely damaged by microorganisms after use and does not cause environmental pollution. More specifically, it is a natural degradable starch of 1 to 99% by weight and polycaprolactone 10 to 75. It is composed of 99 ~ 1% by weight of decomposable synthetic resin composed of weight%, 10-50% by weight of aliphatic polyester, 1 ~ 35% by weight of polyvinyl alcohol and 5-40% by weight of ethylene-vinyl alcohol. To the biodegradable resin composition characterized in that it is melted and kneaded after adding 10 to 10% by weight, other plasticizer to 1 to 5% by weight relative to the total resin composition, and 0.5 to 10% by weight relative to the total resin composition. It is about.

In general, synthetic resin, a petrochemical product, is widely used in all fields because of its excellent physical properties such as chemical resistance, transparency, flexibility, and rigidity, but it does not decompose itself after use, and environmental pollution caused by plastic is a big problem. As a result, the country of decomposable resins is actively progressing, and has attracted much attention all over the world. In particular, as the limits of landfill use and the difficulty of recycling become more difficult, various aspects of research and development have been conducted to alleviate the problem of plastic waste disposal. have.

Generally, degradable resins are classified into biodegradable resins decomposed by microorganisms present in soil and photodegradable resins decomposed by ultraviolet rays of sunlight, but photodegradable resins do not receive light when buried in the soil, and thus are not decomposed. As it has, it is biodegradable and resin is mainly used. Examples of biodegradable resins include general purpose ratios such as polyhydroxyarylate resins synthesized in vivo by microorganisms, polycaprolactone synthetic synthetic biodegradable resins, and thermoplastic resins polyethylene, polystyrene, polypropylene, and polyethylene terephthalate. In order to impart biodegradability to degradable resins, resins filled with natural polymers are known.

In addition, polyhydroxy arylate resin, polycaprolactone and the like is excellent in degradability, but the manufacturing cost is expensive, there is no economical efficiency, the resin added with natural polymer has a problem that the required physical properties are lowered. That is, the natural polymer itself has excellent degradability, but the thermoplastic resin itself is a decomposable resin that does not decompose and partially forms a piece of the resin, causing secondary environmental pollution.

As a natural polymer, the decomposable resin using starch is added to water or plasticizer and added heat and pressure to the starch and thermoplastic synthetic resin, as known in EP 032,802, USP 4,900,361, EP326,517, EP 032,802, EP 327,505, and WP 90/10671. Although the starch structure is destroyed to produce a thermoplastic mixture, satisfactory effects cannot be obtained.

In addition, biodegradable polymer resins made from starch and ethylene-vinyl alcohol copolymers are known from EP 0400,532, which are known to have excellent mechanical properties and water resistance. However, the resin has a problem that the mechanical properties are lowered according to the change in humidity, in particular, in the low humidity has a large odor and the impact strength has been limited to use in the field of packaging products.

Accordingly, an object of the present invention is to provide a method for producing a biodegradable resin that is economical because it is completely decomposed by microorganisms in the soil after use, and does not cause environmental pollution.

In order to achieve the above object as well as another easily expressed object in the present invention, aliphatic polyester, polyvinyl alcohol having a saponification degree of 50 to 99%, polycaprolactone, and both hydrophilic and hydrophobic groups for improving compatibility The ethylene-vinyl alcohol copolymer was mixed to obtain a biodegradable synthetic resin, and melted and extruded like starch in a twin-screw extruder to obtain a biodegradable resin. The biodegradable resin thus removed could be molded into injection molded articles, extruded molded articles, sheets, films and the like.

The present invention is described in more detail as follows.

Biodegradable resin of the present invention is a natural degradable material starch 1-99% by weight and polycaprolactone 10-75% by weight, aliphatic polyester 10-50% by weight, polyvinyl alcohol 1-35% by weight and ethylene-vinyl alcohol 5 It is composed of 99 ~ 1% by weight of decomposable synthetic resin composed of ~ 40% by weight, 10 ~ 50% by weight of water starch as plasticizer, 1 ~ 5% by weight of other plasticizer, and lubricant It relates to a biodegradable resin composition characterized by melting and stirring after adding 0.5-10 weight% with respect to a resin composition.

In the present invention, starch is a starch extracted from potatoes, rice, tapioca, sweet potato, or corn, and the like, which is mainly composed of amylose having a linear structure and amylopectin having a molecular structure. It is preferred to add 1 to 99% by weight based on the composition.

In the present invention, the synthetic resin is used by mixing polycaprolactone, aliphatic polyester, polyvinyl alcohol and ethylene-vinyl alcohol copolymer, and contains 1 to 99% by weight based on the total amount of the total decomposable resin.

The polycaprolactone in the synthetic resin has a molecular weight of 15,000 to 100,000, a melting point of 60 ° C., and contains 10 to 75% by weight of the synthetic resin.

In addition, polyvinyl alcohol has a saponification degree of 50 to 99% and 1 to 33% by weight based on the total synthetic resin.

Aliphatic polyester used in the present invention is a polymer having a high melt viscosity and melt strength, it is an acid component, diol component consisting of 70 to 95 mol% succinic acid residue and 5 to 30 mol% adipic acid residue or succinic acid alone 1 60-95 mol% of 4-4-butanediol residues and 5-40 mol% of hexamethylenediamine residues as amine residues, and only the acid component when the trifunctional or more than trifunctional polyfunctional compound is an acid residue, and diol and amine residues when it is an alcohol residue. 0.01 ~ 1 mol% is added and esterified or transesterified, and the product is added to a reactor equipped with a condenser and a stirrer, and a thermal stabilizer and a catalyst are added to the shaft at a pressure of 1 mmHg or less and a high temperature of 240 to 260 ° C. Intrinsic viscosity obtained by the polymerization reaction is characterized by 1.2 or more.

Succinic acid and adipic acid are used as acid components, and succinic acid esters such as large methyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, and dioctyl succinate instead of succinic acid. Compounds can be used.

Adipic acid functions to control the crystallinity of the aliphatic polyester, and in particular, the use of 5 to 30 mol% of the acid component improves the moldability of the film. The reaction molar ratio of the acid component composed of the succinic acid residue and the adipic acid residue and 1,4-butanediol is reacted at a ratio of 1: 1 to 1: 2.

As the compound having trifunctional or higher polyfunctionality, trimethylolpropane, trimethylol ethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) -isocyanurate, trimethic acid and trimellitic acid Anhydride, benzene tetracarboxylic acid, benzene tetracarboxylic acid anhydride, glycerin, etc. can be used.

These compounds are mixed one or two or more kinds of aliphatic polyester in a small amount of 00.1 ~ 1 mol% in the copolymerization reaction, and acts to rapidly increase the molecular weight of the copolymer, resulting in a significant improvement in the melt strength.

Aliphatic polyester is a high vacuum by esterification or transesterification of the above-mentioned three components, that is, the acid component, 1,4-butanediol and the polyfunctional compound, and then adding a thermal stabilizer and a catalyst in a reactor equipped with a condenser and a stirrer. It is obtained by condensation polymerization at high temperature.

At this time, the polycondensation catalyst was used in the tin compound system or titanium compound system, it was added in the range of 0.01 ~ 0.1 mol% relative to the acid component. The heat stabilizer is used in an amount of 1.0 × 10 ⁻⁷ to 1.0 × 10 ⁻⁶ mol based on 1 g of the oligomer obtained by esterification or transesterification.

In addition, to improve the usability of starch, polycaprolactone, aliphatic polyester and polyvinyl alcohol to improve the fluidity of the resin, hydrophilic properties of starch are improved by using ethylene vinyl alcohol copolymer having hydrophilic and hydrophobic groups as part of the synthetic resin. This improves the mechanical properties and processability to enable molding into a film. At this time, the ethylene vinyl alcon copolymer is a high melting point composite having no ether content of 44%. The density is 1.14g / cm3, melting point of 164 ~ 188 ℃, vitrification transition temperature of 55 ~ 62 ℃, and melt index of 8 ~ 12g / 10min. Particularly preferred. The ethylene-vinyl alcohol copolymer used 5 to 40% by weight based on the total synthetic resin.

In the present invention, a plasticizer, a lubricant, and the like were added to improve processability when preparing a biodegradable resin. As a plasticizer, water, glycerin, ethylene diglycol, polyethylene glycol 1,4-butanediol, or the like was used alone or in a mixture. Triglycerol monostearate, triglycerol distearate, and triglycerol tristearate were used alone or in combination.

The amount of water in the plasticizers was particularly effective to add 20-50% to starch, 1 to 5% by weight of other plasticizers, and 0.5 to 10% by weight of lubricants for the entire composition.

Each component as described above is injected into the enclosed space of the twin-screw extruder with sufficient water to gelatinize the starch, and the composition is melted and extruded by applying heat to the entire composition. Adjust to 10 ~ 30%. At this time, the barrel temperature is 90 ~ 230 ℃, screw RPM is 80 ~ 150, and torque is melt mixed under the conditions of 40 ~ 60 to produce a biodegradable resin.

The biodegradable resin thus prepared can be molded into injection molded articles, sheets, films, and the like.

The following synthesis examples and examples further illustrate the present invention, but do not limit the scope of the present invention.

Synthesis Example 1

1,4-butanediol 99.22 g (0.99 mol), hexamethylenediamine 24.39 g (0.2099 mol), succinic acid 126 g (1.067 mol), 7.3 g (0.0499 mol), trimethylol ethane in a reactor equipped with a stirrer and a condenser 0.4g (0.0033 mol) was added, and the temperature in the reactor was heated up to 120 degreeC over 40 minutes from normal temperature, and it heated up to 210 degreeC over 120 minutes, stirring. At this time, after flowing out the water of the side reaction produced through the condenser completely, 0.12g (0.0003 mol) of titanium tetraburoxide gradually reduced the pressure in the tube to 0.5mmhg over 50 minutes and at the same time increase the temperature in the tube to 245 ℃ After stirring for 180 minutes, the stirring was stopped, nitrogen was introduced into the tube, and the polymer was pressurized and discharged to obtain a desired aliphatic polyester copolymer.

Example 1

20% by weight corn starch, 25% by weight polycaprolactone, 50% by weight aliphatic polyester synthesized in Synthesis Example 1, 5% by weight polyvinyl alcohol having a molecular weight of about 1,700, ethylene-vinyl alcohol (ethylene content 44 mol%) To 80% by weight of synthetic resin consisting of 20% by weight of a mixture of 2% by weight of triclosero monosterate as a lubricant, 4% by weight of glycerin and 10 to 40% by weight of water as a plasticizer Blown films were prepared from pellets obtained by melting, mixing, and extruding in an extruder under the following conditions to perform an elongation and biodegradability test and the results are shown in Table 1.

* Extrusion condition

Scour Speed: 80

Torque: 40

Extruder Barrel Temperature: 110/150/180/190/180/160 ℃

Example 2

Except for adding 10% by weight of polycaprolactone, 50% by weight of aliphatic polyester, 5% by weight of polyvinyl alcohol, and 35% by weight of ethylene-vinyl alcohol, the results are shown in Table 1, and the results are shown in Table 1. It was.

Blown film is manufactured by HAAKE RHEOCORD 90 blown film processing equipment with 25mm diameter of TUBULAT DIE, BLOW-UP RATIO = 4, TAKE-UP SPEED = 20 m / rain, SCREW SPEED = 9RPM, barrel temperature The film of thickness 30-45 micrometers was manufactured at 140/150/150/150 degreeC.

The produced film was measured by the compost method, and this lump can have a useful effect in landfilling by decomposing a stable organic product of the resin by biodegradation.

● Post Method

Aging solid waste with a moisture content of 60% or more at a temperature of 55 to 60 ° C under aerobic conditions to promote the activity of high temperature active fungi present in solid waste to measure the weight loss of CO2 and the amount of CO2 generated by microbial metabolism. The resolution was evaluated. In this way, the degradability evaluation results for 45 days are as follows.

TABLE 1

Claims (15)

1 to 99% of starch, polycaprolactone, aliphatic polyester, polyvinyl alcohol and ethylene-vinyl alcohol by mixing 99 to 1% by weight of a plasticizer, a lubricant, and the like, followed by melt kneading in a twin-screw extruder. Biodegradable resin composition. The biodegradable resin composition according to claim 1, wherein the polycaprolactone has a molecular weight of 15,000 to 100,000 and a melting point of 60 ° C. The biodegradable resin composition according to claim 2, wherein the amount of polycaprolactone is 10 to 75% by weight based on the total synthetic resin. The aliphatic polyester is an acid component consisting of 70 to 95 mol% of succinic acid residues and 5 to 30 mol% of adipic acid residues or succinic acid alone, and 60 to 95 mol of 1,4-butanediol residues as diol components. 5 to 40 mol% of hexamethylenediamine residues in% and amine residues, and 0.01 to 1 mol% of diols and amine residues in the case of alcohol residues, to the acid component when the trifunctional or higher polyfunctional compound is an acid residue. After the polymerization or transesterification, the product is added to a reactor equipped with a condenser and a stirrer, and a thermal stabilizer, a catalyst, and the like are added, and the intrinsic viscosity obtained by condensation polymerization at a pressure of 1 mmHg or less and a high temperature of 240 to 260 ° C is 1.2 or more. Biodegradable resin composition characterized in that. The biodegradable resin composition according to claim 4, wherein the aliphatic polyether is used in an amount of 10 to 50% by weight based on the total synthetic resin. The biodegradable resin composition according to claim 1, wherein the polyvinyl alcohol has a degree of saponification of 50% to 99%. The biodegradable resin composition according to claim 6, wherein the polyvinyl alcohol is used in an amount of 1 to 35% by weight based on the total synthetic resin. The biodegradable resin composition according to claim 1, wherein the ethylene-vinyl alcohol is a high melting point compound having an ethylene content of not more than 44% and has a melt index of 6 to 15 g / min. The biodegradable resin composition according to claim 8, wherein the amount of ethylene-vinyl alcohol used is 5 to 40% by weight based on the total synthetic resin. The biodegradable resin composition according to claim 1, wherein water, glycerin, ethylene diglycol, polyethylene glycol, or 1,4-butanediol is used as the plasticizer. 11. The resin composition according to claim 10, wherein water is added in an amount of 10 to 50% by weight to the starch, and glycerin, ethylene diglycol, polyethylene glycol or 1,4-butanediol are mixed in one or two components or more, and then 1 to 2 parts by weight. A biodegradable resin composition, characterized in that 5% by weight is added. The biodegradable resin composition according to claim 1, wherein the lubricant is triglycerol monostearate, triglycerol distearate, or triglycerol tristearate. 13. The lubricant according to claim 12, wherein one or two or more of triglycerol monostearate, triglycerol distearate, and triclicerol tristearate are mixed to add 0.5-10% by weight of the total composition. Biodegradable resin composition characterized in that. The biodegradable resin composition according to claim 1, wherein the twin-screw extruder is melted, mixed and extruded under conditions of a temperature of 90 to 230 ° C, a screw RPM80 to 150, and a torque of 40 to 60. The biodegradable resin composition according to claim 14, wherein the water content of the resin discharged through the die during extrusion is 5 to 30% of the total resin.