KR20190078387A - Method for preparing biodegradable polymer composition - Google Patents

Abstract

The present invention relates to a method for preparing a biodegradable polymer composition and, more specifically, to a method for preparing an extrusion compound biodegradable polymer composition which is capable of providing a material having excellent mechanical properties and biodegradability by processing a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant through an extrusion compounding process.

Description

METHOD FOR PREPARING BIODEGRADABLE POLYMER COMPOSITION [0002]

The present invention relates to a process for preparing a biodegradable polymer composition, and more particularly, to a process for producing a biodegradable polymer composition by applying an extrusion compounding process to a blend of a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant, And particularly to a method for producing a biodegradable polymer composition exhibiting a high bio content.

Polylactic acid (hereinafter referred to as PLA) has biodegradability and is known to have excellent mechanical properties such as tensile strength and elastic modulus. However, since it has poor elongation properties and is easily cracked, It is a situation.

In addition, studies have been conducted to improve workability and mechanical properties by forming a polyhydroxyalkanoate (hereinafter referred to as PHA) copolymer as another method, but the physical properties are still limited.

In order to prepare a biodegradable polymer composition, two or more resins are conventionally mixed through a solution blend, however, there is a limitation in mass production, and there is a problem that physical properties may be different.

The present invention provides a method for producing a biodegradable polymer composition, which is an extrusion compound composition through an extrusion process which is advantageous for mass production and can evaluate stable properties.

The present invention includes extrusion compounding a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant, and an antioxidant in a water-cooled twin-screw extruder, wherein the extruding compounding step is performed at a temperature For 30 minutes to 1 hour. The present invention also provides a method for producing a biodegradable polymer composition.

The present invention also relates to a biodegradable composition comprising an extrudate of a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant, wherein the elongation is 1 to 300% and the impact strength is 1 to 250 J / m And a method for producing the polymer composition.

Hereinafter, a method for producing a biodegradable polymer composition according to a specific embodiment of the present invention will be described in detail.

According to one embodiment of the invention, there is provided a process for extrusion compounding a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant in a water-cooled twin-screw extruder, Deg.] C for 30 minutes to 1 hour, may be provided.

The present invention relates to a method for producing a biodegradable polymer composition, which comprises extruding a polylactic acid (PLA) resin, a polyhydroxyalkanoate (hereinafter PHA) resin, a dispersant, And a method for producing a biocompound polymer composition comprising a blend resin mixed with an antioxidant.

Also, the biodegradable polymer composition according to the present invention is a blend composition of PLA / PHA / dispersant / antioxidant, which means a biopolymer composite. Most of these components, for example, about 95% or more are biopolymers and biodegradable Lt; RTI ID = 0.0 > compounding < / RTI > composition.

Particularly, the blending resin containing the dispersant and the antioxidant according to the present invention was compounded using an extrusion process. As a result, the mechanical properties such as tensile strength and elastic modulus were superior to PBS and PBAT blending, which are known as conventional PLA additives, In particular, the elongation is about 100 times or more and the impact strength is improved about 5 times or more. This is mainly due to the bio-component, which is different from the conventional solution blending process, and the extrusion process is performed, and the improved result is obtained by including the dispersant and the antioxidant in the blending resin.

In the method of the present invention, PLA, PHA, dispersant and antioxidant may be prepared, and the blending resin may be compounded by a certain extrusion process using an extruder. Specifically, the PLA and the PHA are mixed with each other in a main hopper in the form of powder in the form of pellets of similar size.

In addition, the extrusion compounding step for the blending resin may be carried out at a temperature of 150 to 200 DEG C for 30 minutes to 1 hour. If the extrusion condition is less than the above range, there is a problem that the viscosity of the resin is increased, the flowability is lowered, and the extrusion torque is increased. If the extrusion condition is exceeded, there is a problem that the discoloration and physical properties of the polymer are lowered.

The extruder may be a water-cooled biaxial extruder. The biaxial extruder preferably has an extrusion screw speed of 100 to 200 rpm and a pelletizer speed of 100 to 500 rpm. The extruder may be a rotating twin screw extruder in the same direction, and the screw speed and the pelletizer speed in the extruder may be adjusted to the above range to facilitate the extrusion compounding process.

It is preferable that the discharge temperature of the last discharge portion of the screw of the water-cooled twin screw extruder is 170 to 220 캜, the discharge temperature of the remaining screw portion is 150 to 200 캜, and the temperature of the main hopper is 120 to 170 캜. The last discharge portion of the screw may mean a portion corresponding to 1/20 of the entire length of the entire screw of the water-cooled biaxial extruder. If the temperature of the last discharge portion of the screw is too low in the water-cooled twin-screw extruder, there is a problem that the flowability is poor and the discharge of the resin is not smooth, and if the temperature is too high, the physical properties of the polymer are deteriorated and discolored.

At this time, the blending ratio of the polylactic acid resin and the polyhydroxyalkanoate resin introduced into the extrusion process may be 50 to 90: 50 to 10. Preferably, the blending ratio of the two resins may be from 70 to 90: 30 to 10.

The term "polylactic acid resin" used in the present invention refers to a polymer having lactic acid as a monomer as described later, which exhibits biodegradability and exhibits excellent physical properties such as high rigidity, and may contain polylactic acid or polylactide have.

Specifically, the polylactic acid resin preferably has a high optical purity, and may be at least one selected from the group consisting of poly-L-lactic acid, poly-D-lactic acid and poly L, D-lactic acid. The polylactic acid preferably used in the present invention may have a weight average molecular weight (Mw) of from about 10,000 to about 1,000,000 g / mol, preferably from about 50,000 to about 500,000 g / mol.

The PHA may be a polymer resin produced by culturing a conventional microorganism. As a preferable example, it may be a polymer obtained by selecting an appropriate microorganism and culturing it by adding a polymer precursor to a medium. It can also be obtained by culturing the cells at a temperature suitable for growth of the cells and production of the polymer at the time of culturing and under the medium conditions. Examples of such culture methods include, but are not limited to, batch, continuous, and fed-batch cultivation.

In addition, the polymer precursor may be 3-hydroxypropionate, and the PHA according to the present invention may be poly-3-hydroxypropionate poly-3-hydroxypropionate, P (3HP ) May be preferable.

Also, the polyhydroxyalkanoate resin may contain one or more by-products selected from the group consisting of lactic acid, 3-hydroxybutylate, and 4-hydroxybutylate. By weight or less. The polyhydroxyalkanoate resin can be produced through conventional microbial cultivation. For example, it is possible to obtain a cell containing the polymer and then extracting and purifying the polymer resin in a cell using a specific solvent, and then processing the polymer resin into a form favorable to the extrusion process. The polymer extraction solvent may be distilled water, methanol, butanol, chloroform, and toluene. In addition, a conventional centrifugal separation process may be included in the production process of the polymer.

The dispersant to be added to the extrusion process may be included in an amount of 0.001 to 5% by weight based on 100% by weight of the blend. Preferably, the dispersing agent may be contained in an amount of 0.01 to 3% by weight.

As the dispersing agent, a polymeric, nonionic, anionic or cationic dispersing agent may be used. Examples thereof include polyalkylene glycols and esters thereof, polyoxyalkylene polyhydric alcohols, ester alkylene oxide adducts, alcohol alkylene oxides But are not limited to, at least one selected from the group consisting of adducts, sulfonic acid esters, sulfonic acid salts, carboxylic acid esters, carboxylic acid salts, alkylamide alkylene oxide adducts and alkylamines.

The antioxidant added to the extrusion process may be included in an amount of 0.001 to 1% by weight based on 100% by weight of the blend. Preferably, the antioxidant may be contained in an amount of 0.01 to 0.1% by weight.

The antioxidant may be at least one selected from the group consisting of a hindered phenol antioxidant, an amine antioxidant, a thio antioxidant, and a phosphine antioxidant, but is not limited thereto.

Specific examples of the antioxidant include phosphoric acid type heat stabilizers such as phosphoric acid, trimethyl phosphate or triethyl phosphate; Butyl-p-cresol, octadecyl-3- (4-hydroxy-3,5-di-t- butylphenyl) propionate, tetrabis [methylene- Butyl-4-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di- 4-hydroxybenzylphosphite diethyl ester, 2,2-thiobis (4-methyl-6-t-butylphenol), 2,6-g, (3-methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl- (4'-hydroxy-3'-tert-butylphenyl) butanoic acid] glycol ester (Bis [3,3- Hindered phenol-based primary antioxidants such as esters; Amines such as phenyl-? -Naphthylamine, phenyl-? -Naphthylamine, N, N'-diphenyl-p-phenylenediamine or N, N'-di-? -Naphthyl- Secondary antioxidant; Thio such as dilauryl disulfide, dilauryl thiopropionate, distearyl thiopropionate, mercaptobenzothiazole, or tetramethyl thiuram disulfide tetrabis [methylene-3- (laurylthio) propionate] Secondary antioxidants are; (2,4-ditbutylphenyl) pentaerythritol diphosphite or (1, 2,4-dibutylphenyl) pentaerythritol diphosphite or bis (2,4-dibutylphenyl) (1,1'-biphenyl) -4,4'-diisopropylphosphonic acid tetrakis [2,4-bis (1,1-dimethylethyl) phenyl] -Diylbisphosphonous acid tetrakis [2,4-bis (1,1-dimethylethyl) phenyl] ester).

When the blending resin containing the dispersant and the antioxidant is compounded using an extrusion process, mechanical properties such as tensile strength and elastic modulus are excellent, and in particular, the elongation is approximately equal to that of PBS and PBAT blending, which is known as conventional PLA additives 100 times or more, and the impact strength is improved about 5 times or more.

According to a preferred embodiment of the present invention there is provided an extrudate of a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant, wherein the elongation is 1 to 300% and the impact strength is 1 to 250 J / m A biodegradable polymer composition may be provided.

The extrudate may have a tensile strength of 10 to 100 MPa and a tensile modulus of 1 to 5 GPa.

The extrudate may also be in the form of a pellet having a thickness of 10 to 50 mm.

The biodegradable polymer composition according to the method of the present invention has excellent mechanical properties and can occupy about 95% by weight or more of biodegradable material. Therefore, the biodegradable polymer composition can be easily applied as a biodegradable material. Further, the biodegradable polymer composition of the present invention improves the blendability of two or more kinds of resins by a specific extrusion compounding process, and thus can provide an effect capable of mass production.

According to the present invention, a blending resin in which PLA and a polyhydroxyalkanoate resin are mixed is subjected to compounding by an extrusion process differently from the conventional solution blending process, thereby providing a biodegradable polymer composition. Further, according to the present invention, it is possible to exhibit excellent mechanical properties and also to be capable of mass production.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

 [Example 1]

A blending resin of 93 wt% of PLA, 5 wt% of poly 3-hydroxypropionate (hereinafter referred to as P (3HP)), 0.1 wt% of an antioxidant (Irganox 1010) and 1.5 wt% of a dispersant (BYK P- After the addition to the twin-screw extruder, extrusion compounding was carried out under the following conditions to prepare a biodegradable polymer composition and pelletization proceeded.

- extrusion screw speed: 100 rpm / pelletizer speed: 400 rpm

- extruder internal temperature

 (1) Screw Last discharge part: 210 ℃

 (2) Remaining screw parts: 190 ° C

 (3) Main hopper: 160 ° C

After extrusion, a pelletized sample was hot-pressed to produce a polymer sheet, which was then processed into dog bone specimens and impact strength specimens. The UTM and Izod impact were then performed. The results of mechanical properties are shown in Table 1.

<Experimental Method>

Tensile Strength: Measured according to ASTM D638 one method.

Tensile Modulus: Measured according to ASTM D638 one method.

Elongation to Break: Measured according to ASTM D638 one method.

Izod Impact: Measured according to IS0 180 one method.

[Example 2]

The extrusion compounding process was carried out in the same manner as in Example 1 except that the blend composition was changed to 88 wt% of PLA and 10 wt% of P (3HP) instead of 93 wt% of PLA and 5 wt% of P (3HP) A composition was prepared. The results of mechanical properties are shown in Table 1.

[Reference Examples 1 to 2]

Instead of 93% by weight of PLA and 5% by weight of P (3HP), 88% by weight of PLA and 10% by weight of PBS; Or 88% by weight of PLA and 10% by weight of PBAT, respectively, were subjected to an extrusion compounding process in the same manner as in Example 1 to prepare a composite resin composition. The results of mechanical properties are shown in Table 1.

PLA Blend
(wt%) Antioxidant (wt%) Dispersant (wt%) Tensile Strength (MPa) Tensile modulus (GPa) Elongation (%) Izod impact strength (J / m) Example 1 P (3HP) 5 0.1 1.5 55.3 3.3 155.0 77.3 Example 2 10 51 3.1 185 106 Reference Example 1 PBS 10 42.4 2.1 171.7 41.3 Reference Example 2 PBAT 38.7 2.1 210 57.6

[ Comparative Example  1 to 4]

95% by weight of PLA instead of 93% by weight of PLA, 5% by weight of poly 3-hydroxypropionate (hereinafter referred to as P (3HP)), 0.1% by weight of an antioxidant (Irganox1010) and 1.5% by weight of a dispersant (BYK P- And 5% by weight of P (3HP) / PBS / PBAT were substituted for the blend composition, the extrusion compounding process was carried out in the same manner as in Example 1 to prepare a composite resin composition. The results of mechanical properties are shown in Table 2.

PLA Blend
(wt%) The tensile strength
(MPa) Tensile modulus (GPa) Elongation (%) Izod
Impact strength
(J / m) Comparative Example 1 P (3HP) 5 55.6 2.5 3.8 28.3 Comparative Example 2 PBS 5 57.0 2.5 3.5 22.4 Comparative Example 3 PBAT 5 55.4 2.5 3.1 24.2

According to the Tables 1 and 2, the composite resin compositions of Examples 1 and 2 exhibited an elongation of 50 times or more and an Izod impact strength of 3 times or more as compared with the compositions of Comparative Examples 1 to 3 which did not contain an antioxidant and a dispersant It was confirmed that it was excellent. In addition, Examples 1 and 2 confirmed that the tensile strength, the tensile modulus and the Izod impact strength were superior to those in Reference Examples 1 and 2, which included an antioxidant and a dispersant but contained PBS / PBAT.

Claims (12)

Extrusion compounding a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant in a twin-screw extruder,
Wherein the extruding compounding step is performed at a temperature of 150 to 200 DEG C for 30 minutes to 1 hour.
The method according to claim 1,
Wherein the biaxial extruder has an extruding screw speed of 100 to 200 rpm and a pelletizer speed of 100 to 500 rpm.
The method according to claim 1,
Wherein the discharge temperature of the last discharged portion of the screw of the water-cooled twin-screw extruder is 170 to 220 占 폚, the discharging temperature of the remaining screw portion is 150 to 200 占 폚, and the temperature of the main hopper is 120 to 170 占 폚 Way.
The method according to claim 1,
Wherein the polylactic acid resin and the polyhydroxyalkanoate resin are contained in a weight ratio of 50:90 to 50:10.
The method according to claim 1,
Wherein the dispersing agent comprises 0.001 to 5% by weight based on 100% by weight of the blend.
The method according to claim 1,
Wherein the antioxidant is contained in an amount of 0.001 to 1% by weight based on 100% by weight of the blend.
The method according to claim 1,
Wherein the polyhydroxyalkanoate resin is poly 3-hydroxypropionate. 2. The biodegradable polymer composition according to claim 1, wherein the polyhydroxyalkanoate resin is poly-3-hydroxypropionate.
The method according to claim 1,
Wherein the polyhydroxyalkanoate resin comprises at least 1% by weight of at least one by-product selected from the group consisting of lactic acid, 3-hydroxybutyrate, and 4-hydroxybutyrate.
The method according to claim 1,
Wherein the polylactic acid has a weight average molecular weight of 50,000 to about 500,000 g / mol.
The method according to claim 1,
Wherein the blend further comprises PBS, PBAT, or a mixture thereof.
An elongation of 1 to 300%, an impact strength of 1 to 250 J / m,
A process for preparing a biodegradable polymer composition, comprising an extrudate of a blend comprising a polylactic acid resin, a polyhydroxyalkanoate resin, a dispersant and an antioxidant.
12. The method of claim 11,
Wherein the extrudate has a tensile strength of 10 to 100 MPa and a tensile modulus of 1 to 5 GPa.