KR100200415B1 - Process for preparing biodegradable aliphatic copolyester - Google Patents

Abstract

The present invention relates to a method for producing biodegradable aliphatic polyester that is used for disposable films, fibers, nonwoven fabrics, injection molding, and the like, and is decomposed by microorganisms present in soil when disposed of. On the other hand, it is devised to provide a biodegradable polymer material having excellent mechanical properties and melt strength.

In order to achieve the above object, the present invention is an esterification reaction of a mixture consisting of an acid component composed of succinic acid and the like, a diol component using 1,4-butanediol and the like, and a polyfunctional compound having a small amount of hydroxy or alcohol groups. After the addition, an organosilicon compound having a specific structure is added together with other additives to provide a biodegradable aliphatic polyester production method.

Description

Biodegradable aliphatic polyester manufacturing method

The present invention relates to a method for producing a new aliphatic polyester that is decomposed by microorganisms present in the soil upon disposal after use, and in particular, a biodegradable aliphatic polyester that can be used for disposable films, fibers, nonwoven fabrics, and injection molding processing. It relates to a manufacturing method.

Generally, synthetic resins, which are petrochemical products, are widely used in all fields because of their excellent chemical resistance, transparency, flexibility, and strength, but they are not decomposed after use, but become a social problem of environmental pollution by waste plastic. The use of resins that are present is gradually expanding.

Degradable resins can be classified into photodegradable resins decomposed by ultraviolet rays of sunlight and biodegradable resins decomposed by microorganisms present in the soil. The biodegradable resins are also divided into various types according to manufacturing methods and raw materials. PHB-based resins synthesized in vivo and polycaprolactone, polylactide, and aliphatic polyesters synthesized by the polycondensation of diols and diacids are excellent in biodegradability, but have good physical properties and economic efficiency. Because of its weakness, it is not suitable as a general-purpose polymer material. In particular, polycaprolactone has a low melting point and is known to have problems in thermal stability and dimensional stability. Biodegradable resins have the disadvantage that starch is decomposed, but general purpose resins are not decomposed and are crushed into small pieces to remain in the soil, causing secondary environmental pollution.

The object of the present invention is to improve the molecular weight of the aliphatic polyester, which is used as a coating material or an adhesive, unlike a high melting point aromatic polyester such as polyethylene terephthalate, but the film formability is not good enough to greatly increase the melt viscosity and melt strength. The improvement is to produce aliphatic polyester copolymers that can be used in the manufacture of blown films.

In the case of using a reaction compound capable of forming crosslinking to enable the polyethylene terephthalate or polybutylene terephthalate resin to be blow molding, there are US Patent Nos. 4219527 and 1912167. There is no example in which the blown film etc. were manufactured using all the diol components using an aliphatic compound. In the case of using an aliphatic compound as an acid component and a glycol component, even if the polycondensation reaction is carried out through esterification or transesterification, it is difficult to obtain sufficient melt viscosity or melt strength to give excellent film formability and processability. Also, problems arise in that process workability and mechanical properties of molded products are poor.

On the other hand, the method of improving the mechanical properties or the melt strength is generally used to increase the molecular weight. When the molecular weight is excessively increased, the melt viscosity becomes very high and it becomes very difficult to pass through the extruder during processing. Do. The melt strength of a polymer is usually determined by the elasticity of the polymer melt, and the factors affecting the elasticity include molecular weight distributlon, degree of branch, and additives. In general, the greater the molecular weight, the larger the degree of branching, and the more entanglement of the polymer melt, the higher the elasticity. In the case of polyester, it is also known that particles such as stearic acid or talc and silica have an effect of improving melt strength. Another factor that greatly affects the molding process is the crystallization rate, and the crystallization rate and crystallization of the polymer may be controlled according to the molding process.

In addition, Japanese Patent Nos. 92-189822, 92-189823, etc., through esterification reaction of aliphatic dicarboxylic acids and aliphatic diglycols, after condensation polymerization reaction, add an isocyanate compound to react and increase the molecular weight to increase the melt viscosity and melting. A method of improving strength has been proposed, but has not reached a satisfactory level.

In order to achieve the above object, the present invention performs an esterification reaction based on aliphatic alcohols and aliphatic carboxylic acids having a specific structure, and then adds an organosilicon compound represented by the following general formula (I) to polycondensation reaction: It proceeds to provide a method for producing an aliphatic polyester having a high melt viscosity and melt strength.

Where R is CH3 or , m, n are integers)

Hereinafter, the present invention will be described in detail.

Specifically, the present invention relates to an acid component composed of 40 to 90 mol% of succinic acid or its ester compound, and 10 to 60 mol% of adipic acid or its ester compound, and 1, 4-butanediol or ethylene glycol alone or in two components. After esterifying a mixture consisting of a mixed diol component and a compound having a multifunctional compound having three or more hydroxyl groups or alcohol groups, the organosilicon compound of Formula (I) is 0.1 to 5% by weight relative to the ester reactant. It is characterized in that the polycondensation by addition with an additive.

That is, in the present invention, succinic acid and adipic acid are used as an acid component, and succinic acid ester compound instead of succinic acid and adipic acid ester compound instead of adipic acid may be used. In addition, the diol component is used alone or mixed in 1, 4-butanediol or ethylene glycol, the reaction molar ratio of the acid component and the diol component is preferably reacted in a ratio of 1: 1 to 1: 2, more preferably 1: Reaction at a ratio of 1.2 to 1: 1.7 is more advantageous in terms of reactivity and the physical properties and color tone of the obtained polymer.

In the present invention, the compound having a trifunctional or higher polyfunctionality is trimethylol propane, trimethylol ethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate, trimellitic acid, trimellitic acid Anhydrides, benzene tetracarboxylic acid, benzene tetracarboxylic acid anhydride and the like can be used. Compounds having a trifunctional or higher polyfunctionality are added to the succinic acid in the range of 0.01 to 1 mol% to react, and when copolymerized in the range of more than 1 mol%, the reaction proceeds in a very short time to obtain a high molecular weight. A polymer can be obtained, but the crosslinking degree is rapidly increased, so that a gel is formed, which is not suitable for molding, and is easily obtained. When the copolymerization is less than 0.01 mol%, the addition effect is insignificant.

In the present invention, after the completion of the ester reaction, the polycondensation reaction is carried out by adding the organosilicon compound of general formula (I). The organosilicon compound not only exhibits the characteristics as an antifoaming agent during the condensation polymerization but also by condensation polymerization. By improving the hydrolysis resistance or resistance to ultraviolet rays of the produced aliphatic copolyester, it exhibits effects such as improvement over time and prevention of changes in mechanical properties of the film due to moisture. The amount of the organosilicon compound used is 0.1 to 5% by weight based on the ester reactant. If the amount is less than 0.1% by weight based on the esterification product, the use effect is almost insignificant. This delay is extremely delayed, rather acts as a factor to inhibit the film processability and biodegradability is also a problem occurs. Silicon organic compound of the general formula (I) used in the present invention is advantageous in the case of polycondensation polymerization having a viscosity of about 100 ~ 5000cs. If the viscosity is less than 100 cs, the heat resistance of the organosilicon compound is poor and it inhibits the polycondensation reaction. If the viscosity is more than 50,000 cs, the gel is formed by forming a gel even though the self-decomposition of the silicon compound is minimal during the polycondensation reaction. When forming a film from polymerized aliphatic copolyester, workability becomes very poor.

As the polycondensation catalyst usable in the present invention, tin compounds and titanium compounds are particularly excellent in effect. Examples of the tin compound include tin oxides such as tin oxide and tin oxide, halogen tins such as tin chloride and tin tin, monobutyl tin oxide, dibutyl tin oxide, and monobutyl hydroxy tin oxide. And organotin compounds such as dibutyl tin dichloride, tetra phenyl tin and tetra butyl tin. Examples of the titanium compound include tetra butyl titanate, tetra methyl titanate, tetra isopropyl titanate, and tetra (2-ethylhexyl). Titanate and the like can be used, and the amount of addition is suitably used within the range of 0.01 to 0.1 mol% with respect to the acid component. In this case, when the amount of the catalyst is used too much, the discoloration of the polymer occurs badly, and when too little, the reaction rate is slowed.

In the present invention, a phosphorus compound is used as a heat stabilizer, for example, phosphoric acid, monomethyl phosphate, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, monophenyl phosphate, triphenyl phosphate and derivatives thereof, phosphorous acid and triphenyl. Phosphorous acid, trimethylphosphoric acid and derivatives thereof, Iganox 1010, Iganox 1222, Igafos 168, phenyl phosphonic acid, and the like, among which phosphoric acid, trimethyl phosphoric acid, triphenyl phosphoric acid and the like have excellent effects. The amount of phosphorus compound as thermal stabilizer is 1.0 × 10 ^-7 to 1.0 × 10 ^-6 mol / gram oligomer, more preferably 0.5 × 10 ^-6 to 1.5 × 10 ^-6 , for the oligomer obtained by esterification or transesterification reaction. Mole / gram oligomers are preferred.

In the present invention, in order to obtain a high molecular weight aliphatic copolymer polyester having a high melt viscosity and a high melt strength, it is necessary to polycondense under high vacuum conditions of 1 mmHg or less, and the reaction temperature is effective at 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, and if it exceeds 260 ℃ rather than the thermal decomposition is worse the physical properties and color tone of the obtained polymer.

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

The intrinsic viscosity (dl / g) of the polyesters measured in Examples and Comparative Examples was measured by dissolving in orthochlorophenol solution at 35 ° C., and tensile strength (kg / cm ² ) and elongation at break in accordance with ASTM D-412 ( %) Was measured.

In addition, the degradability of the prepared biodegradable resin was measured in a film state by the compost method, and the composition of the compost method was prepared as shown in Table 1 as shown in the composition ratio of garbage generated in Korea, and the internal environment was as shown in Table 2 below. The samples were buried and the weight loss was measured for 10 weeks to evaluate the resolution.

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 into 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 resulting side reaction product was completely discharged through a condenser to obtain an esterification reaction product. Then, 25 g of a silicon compound having a viscosity of 200 cs and 1.70 g of tetrabutyl titanate as a catalyst were added thereto, and the internal pressure was increased over 45 minutes. While slowly depressurizing to 0.5mmHg and proceeding with a stirring reaction for 120 minutes while raising the temperature of the tube to 245 ° C, the stirring was stopped and nitrogen was injected into the tube to pressurize and discharge the polymer to obtain the desired aliphatic copolymer polyester. . The physical properties of the polyester resin prepared as a counterfeit and the blown film having a thickness of about 30 μm prepared from the resin are shown in Table 3.

Example 2

Into a reactor equipped with a stirrer and a condenser, 960.4 g (8.133 mol) of succinic acid, 509.3 g (3.485 mol) of adipic acid, 1070.4 g (11.62 mol) of 1,4-butanediol, and 180.32 g (2.905 mol) of ethylene glycol were added thereto. The temperature in the reactor was elevated to 210 ° C. over 120 minutes from normal temperature. At this time, the resulting side reaction product was completely discharged through a condenser to obtain an esterification reaction product. Then, 25 g of a silicon compound having a viscosity of 200 cs and 1.70 g of tetrabutyl titanate as a catalyst were added thereto, and the internal pressure was increased over 45 minutes. While slowly depressurizing to 0.5mmHg and proceeding with a stirring reaction for 120 minutes while raising the temperature of the tube to 245 ° C, the stirring was stopped and nitrogen was injected into the tube to pressurize and discharge the polymer to obtain the desired aliphatic copolymer polyester. . In addition to the polyester resin prepared as described above, the physical properties of the blown film having a thickness of about 30 μm prepared from this resin are shown in Table 3.

Comparative Example 1

After carrying out the esterification reaction, the polycondensation reaction was carried out without adding the silicone compound, and was carried out under the same conditions as in Example 1. The physical properties of the resulting resin and film are shown in Table 3.

Comparative Example 2

Except for using 150 g of S-1 as the silicone compound after the esterification reaction was carried out under the same conditions as in Example 1, the physical properties of the resulting resin and film are shown in Table 3.

Comparative Example 3

Except for using 25g of S-2 having a viscosity of 60,000cs as a silicone compound after the esterification reaction was carried out under the same conditions as in Example 1, the physical properties of the resulting resin and film are shown in Table 3.

[Comparative Example 4]

Except not using trimethylol ethane during the esterification reaction was carried out under the same conditions as in Example 1, the physical properties of the resulting resin and film are shown in Table 3.

[Comparative Example 5]

The esterification reaction was carried out under the same conditions as in Example 1 except that 16.9 g (0.139 mol) of trimethylol ethane was used, and the physical properties of the resulting resin and film are shown in Table 3.

Comparative Example 6

Except for using succinic acid 1372g (11.615mol) alone as the acid component was carried out under the same conditions as in Example 1, the physical properties of the resulting resin and film are shown in Table 3.

The film used for measuring the physical properties of Table 3 was prepared to have a thickness of about 30 μm using a RHEOCORD 90 blown film processing facility of HAAKE having a diameter of a tubular die of 25 mm.

The change over time was compared with the initial physical properties immediately after the film processing and after 1 month in a constant temperature and humidity chamber maintained at 30 ℃, 80% relative humidity.

* I.V. Intrinsic viscosity

* M.S. Melt strength

Claims (5)

An acid component consisting of 40 to 90 mol% of succinic acid or its ester compound and 10 to 60 mol% of adipic acid or its ester compound, a diol component of 1,4-butanediol and ethylene glycol alone or in a mixture of two components, and After esterification of a mixture of a polyfunctional compound having a small amount of hydroxy groups or alkoxy groups of three or more, 0.1-5% by weight of the organosilicon compound of general formula (I) is added to the ester reactant to condensation polymerization. Biodegradable aliphatic polyester manufacturing method characterized in that it is prepared. Where R is CH ₃ or , m, n are integers). The method for producing biodegradable aliphatic polyester according to claim 1, wherein the organosilicon compound has a viscosity of 100 to 500,000cs. The method of claim 1, wherein the molar ratio of the acid component to the diol component is 1: 1 to 1: 2. The polyfunctional compound according to claim 1, wherein the polyfunctional compound is trimethylol propane, trimenolethane, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanurate, trimellitic acid, trimellitic anhydride, benzene Method for producing a biodegradable aliphatic polyester, characterized in that selected from tetracarboxylic acid, benzene tetracarboxylic anhydride. The method of claim 1, wherein the polyfunctional compound is used in the range of 0.01 to 1 mol% based on succinic acid.