KR20060003580A - Biodegradable polyester resin composition containing nano particles - Google Patents

Abstract

The present invention provides a biodegradable polyester resin composition by mixing polylactic acid with respect to an aromatic-aliphatic polyester resin in which nanoparticles are dispersed and mixed into glycols and subjected to a condensation polymerization reaction. The surface of the nanoparticles can be modified with various intercalants. In addition, a plasticizer, a nucleating agent, an antiblocking agent, a crosslinking agent, or the like may be added to improve the secondary processability of the resin composition, and may be applied to applications such as films, fibers, and molded products.

Aromatic-aliphatic polyesters, polylactic acids, nanoparticles, biodegradable

Description

Biodegradable polyester resin composition containing nano particles

Synthetic plastics are used for various purposes all over the world because of their excellent properties and cheap and light properties. However, due to the problem of poor decomposition, which is the advantage and disadvantage of synthetic plastics, many countries have recently been interested in finding a solution. In the meantime, landfilling, incineration and regeneration have been mainly used, but these methods cannot completely solve the environmental pollution problem. Therefore, attention is focused on the development of so-called degradable plastics, which enables the used plastics to decompose themselves. The subdivision of technology related to degradable plastics is divided into biodegradation technology, photodegradation technology and bio-photodegradation technology combining these two technologies. Biodegradable plastics include microorganism-producing polymers such as poly-hydroxybutylate (PHB), macromolecules based on microbial-producing biochemicals, natural polymers such as aliphatic polyesters and chitins, and starch (chitin). There are many forms, such as plastic with added back. However, these plastics are inferior in mechanical properties compared to conventional plastics, and because of the high price, inexpensive starch, etc. must be mixed, resulting in a problem of deterioration of transparency and mechanical properties.

In order to solve such a problem, the present invention solves problems such as mechanical strength and transparency by adding nanoparticles to a composition made of degradable plastic having two different functionalities. The technology related to nanoparticles here is based on nanotechnology that utilizes the functions expressed when controlling the characteristic length of a polymer or inorganic material at the nanometer (10 ^-9 m) level. By intercalation or exfoliation into the polymer, the polymer is dispersed in the polymer and thus has superior physical properties than the existing polymer materials. Generally speaking, nanoparticles refer to inorganic particles, organic particles or ultrafine particles of metal or metal oxides having nanometer size of 1 to 100 nm in diameter. Conventional techniques using nanoparticles in polymers have been commercialized by Toyota Japan, a timing belt cover made of nanocomposite materials made of nylon, and with Monte North America of the United States. GM's joint research revealed that the car door and rear panel of the Clay / TPO nanocomposite were manufactured by injection molding. In addition, in the prior art, the nano-sized clay may be dispersed in the biodegradable resin, but the object of the biodegradable resin is unclear and the nanoparticles are limited to the clay.

In general, the biggest problem in the production of such nanoparticles is the aggregation (aggregation). Various methods using surfactants or polymers have been tried to prevent the aggregation of nanoparticles. In particular, since most polymers have good processability, they are often used as a matrix for stabilizing nanoparticles. However, since there is no affinity between the nanoparticles and the polymer, the nanoparticles are not dispersed properly in the polymer resin, and in this case, aggregation between particles occurs, which is known to adversely affect the physical properties of the polymer resin.

In order to solve this problem, the present inventors carried out a condensation polymerization reaction by dispersing and mixing nanoparticles into glycols in an aromatic-aliphatic polyester resin, and thus excellent dispersibility of nanoparticles. In addition, the present invention is characterized by providing a biodegradable resin composition having improved processability and flexibility, which is an advantage of the aromatic-aliphatic polyester resin, and mechanical strength and transparency, which is an advantage of the polylactic acid. In order to achieve this purpose, the surface of the nanoparticles is modified with various intercalants, and a plasticizer, a nucleating agent, an antiblocking agent, a crosslinking agent, or the like is added to improve the secondary processability of the resin composition. It features.

The present invention comprises a bio-degradable polyester resin composition comprising 60 to 5 parts by weight of aromatic-aliphatic polyester and 95 to 40 parts by weight of polylactic acid and 0.1 to 10 parts by weight of nanoparticles based on 100 parts by weight of the mixed composition. It is about. In addition, a plasticizer, a nucleating agent, an antiblocking agent, a crosslinking agent, or the like may be added in order to apply the present resin composition to applications such as films, fibers, molded articles, and the like.

The aromatic-aliphatic polyester used is a dicarboxylic acid having a structure of ROOC-Ar-COOR '(R, R' is hydrogen or an alkyl group) or a derivative thereof with terephthalic acid, phthalic acid, isophthalic acid, naphthalene 2,6- Dicarboxylic acid, diphenyl sulfonic acid dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxy ethane dicarboxylic acid, cyclohexanedicarboxylic acid, or alkylene thereof At least one selected from the group consisting of esters. Aliphatic dicarboxylic acids or derivatives thereof include succinic acid, glutaric acid, malonic acid, oxalic acid, adipic acid, having a structure of ROOC (CH ₂ ) nCOOR '(R, R' is hydrogen or alkyl group, n is 2-14) At least one member selected from the group consisting of sebacic acid, azelaic acid, nonanedicarboxylic acid and alkyl or aryl ester derivatives thereof. Glycols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol having a structure of HO- (CH ₂ ) n-OH (n is 2 or more). Or a group consisting of alkylene glycol and polyalkylene glycol composed of propylene glycol, 1,4-cyclohexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, neopentyl glycol, tetramethylene glycol, and general formula (1) 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1, which are aliphatic dihydric alcohols capable of forming a branched structure represented by 4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,2-octanediol, 1,3-octanediol, 1,4 One or more substances selected from the group consisting of -octanediol, 1,5-octanediol, 1,6-octanediol and the like can be used.

General formula (1)

HO-R ₁ -OH

   |

R ₂

In said general formula (1), R <_1> is a C2-C8 alkylene group and R <_2> is a C2-C8 alkyl group.

The aromatic-aliphatic polyester component of the aromatic component should be adjusted to 10 to 50 mol%, preferably 30 mol% is the best. If the aromatic is 10 mol% or less, the rubbery properties required in the present resin composition are weakened, and the elastic modulus is lowered.

The polylactic acid used consists of L-lactic acid, D-lactic acid or L, D-lactic acid, with a molecular weight of at least 10,000. These polylactic acids may be used alone or in combination.

As nanoparticles, inorganic nanoparticles include clays, silica sol, titania sol, alumina sol, and the like, and organic polymer nanoparticles, metal particles such as palladium, platinum, gold, and silver may also be used.

Clay is selected from the group consisting of montmorilonite, bentonite, hectorite, saponite, attapulgite, sepiiorite and vermiculite, etc. It is good to organic the clay by modifying the surface. For example, Na + -montmorilonite is known to be swellable by water, but it is impossible to infiltrate other organic materials. This is because the distance between the layers is only about 2 nm. In order to facilitate the intercalation of organic materials, it is necessary to increase the lipophilic properties of clay by using an organic agent composed of a cationic head and a lipophilic tail. have. At this time, the cationic head exchanges Na + ions on the clay surface, and the lipophilic tail facilitates the intercalation of organic materials by increasing the interaction with the polymer and increasing the distance between silicates.

As a solvent for dispersing these nanoparticles, glycols include ethylene glycol, propylene glycol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, hexamethylene glycol, It consists of at least 1 sort (s) chosen from the group which consists of an alkylene glycol consisting of polyethyleneglycol, triethylene glycol, 1, 3- propanediol, 1,2-propanediol, neopentyl glycol, propylene glycol, and tetramethylene glycol.

The composition is first required for the polymerization process of aromatic-aliphatic polyester, the slurry (SLURRY) dispersed in 1 to 30 parts by weight of nanoparticles in 100 parts by weight of the glycol solution is aromatic- while maintaining the pH of 4-8 It is mixed during the esterification of aliphatic polyester.

The size of the nanoparticles is preferably less than 100nm, if larger than this may have a problem that the transparency is lowered. 0.1 to 10 parts by weight of nanoparticles should be contained in 100 parts by weight of the mixed composition of the polymerized aromatic-aliphatic polyester and polylactic acid. At 0.1 parts by weight or less, the mechanical properties do not improve, and at 10 parts by weight or more, transparency is lowered, and mechanical properties are rather deteriorated due to an increase in defects due to aggregation between nanoparticles.

In the case of aromatic-aliphatic polyesters, the aromatic component should be adjusted to 10-40 mole%, preferably 30 mole%. If the aromatic content is less than 10 mol%, the properties of the aromatic-aliphatic polyester are similar to those of the aliphatic polyester, so that when the film is mixed with the polylactic acid, the strength tends to decrease due to crystallinity, and the melting point difference with the polylactic acid is different. Due to this, secondary workability tends to be poor. On the contrary, when the aromatic content is 40 mol% or more, the aromatic-aliphatic polyester has a strong rubbery property, which causes a problem of sticking during film production.

As such, since the nanoparticles serve as an excellent nucleating agent in the polymer structure, the aromatic-aliphatic polyester having improved mechanical strength is formed differently according to the use in a weight ratio of polylactic acid and 60:40 to 5:95.

In general, when the blending ratio of polylactic acid is less than 40% by weight, mechanical properties, transparency, etc. are reduced, and when it is more than 95% by weight, there is a problem in elongation of the film due to lack of flexibility.

In addition, plasticizers aiming at improving the secondary processability of these mixtures are commonly used in polylactic acid and aromatic-aliphatic polyesters, and may be ether ester plasticizers, oxyacid ester plasticizers, or glycol plasticizers. Specifically, ethylene glycol, Propylene glycol, polyethylene glycol, sorbitol, glycerin (glycerol), methoxypolyethylene glycol, tri-n-butyl citrate, and the like. Moreover, it is also possible to mix and use two or more types in these mixtures. The composition may be used as additives, such as a sunscreen, antibacterial / deodorant, heat stabilizer, light stabilizer, flame retardant, antistatic, antioxidant, pigments, depending on the application.

The composition is prepared by melt kneading in a twin-screw kneading extruder by mixing a predetermined amount of the polylactic acid, aromatic-aliphatic polyester, additives and the like, and is produced in pellet form to have a shape of a film, a fiber, a molded article or the like.

As described above, the present invention relates to a composition in which polylactic acid is mixed with an aromatic-aliphatic polyester in which nanoparticles are excellently dispersed, and has improved physical properties, flexibility, mechanical strength, and transparency, but has properties similar to those of conventional plastics. After this is completed, biodegradation is performed under normal composting conditions.

The following examples and comparative examples are intended to illustrate the present invention in more detail, and do not limit the scope of the present invention. First, the measurement and evaluation methods necessary for the explanation of the present invention were performed under the following conditions.

 (1) Mechanical Strength (Tensile Strength; ASTM D 638)

Using a tensile tester, the measurement was performed at a tensile rate of 500 mm / min at a temperature of 20 ± 2 ° C. and a relative humidity of 65 ± 2%. In addition, MD and the width direction were shown for the longitudinal direction of the film by TD.

(2) Flexibility (elongation; ASTM D 638)

Elongation until fracture of the film was determined under the same conditions as the tensile strength.

(3) Transparency (ASTM D 1003)

5cm wide and vertical specimens are fabricated to transmit light having a wavelength of 400-700nm using Haze Meter (Nippon Denshoku), which is a turbidity measuring instrument.At this time, 10% or less of Haze% is measured for scattered light against battle light. 1, 11-19% is 2, and 20% or more are represented by 3.

(4) Exploded View (KS M 3100-1)

The biodegradability of the test material was calculated from the cumulative amount of carbon dioxide released (using the following formula) for 45 days by composting the test material under the same conditions using TLC grade cellulose having a particle size of 20 μm or less as a standard sample. When the degree of decomposition of the standard sample is 100, the biodegradability of the test substance is calculated as%, and more than 80% is expressed as 1, 80 to 50% is expressed as 3 and less than 50%.

Dt = [{(CO ₂ ) _T- (CO ₂ ) _B } / ThCO ₂ ] × 100

(CO ₂ ) _T : Accumulated amount of carbon dioxide from the container containing the test substance

(CO ₂ ) _B : Accumulated amount of carbon dioxide from containers containing compost

ThCO ₂ : Calculation of Theoretical Carbon Dioxide

ThCO ₂ = M _TOT × C _TOT × (44/12)

M _TOT : Total dry solids (g) of test substance added at the start of analysis

C _TOT : percentage of organic carbon in the total dry solids of the test substance (g / g)

            44,12: molecular weight of carbon dioxide and atomic weight of carbon

 (Example 1)

Aromatic-aliphatic polyester is composed of dimethyl terephthalate, succinic acid, glutaric acid, adipic acid, ethylene glycol and 1,4-butanediol with an aromatic content of 30 mol%. 0.5kg clay of surface-modified montmorillonite (MMT-25A manufactured by Southern Clay Co.) was polymerized to produce 60 kg of PLA POLYMER polymer from Cargill Dow as a polylactic acid and a plasticizer as other additives. 10 kg methoxypolyethylene glycol, 5 kg tri-n-butyl citrate, 0.5 kg bohenamide, an amide lubricant, 2,5-dimethyl-2,5 as crosslinking agent -di (tert-butylperoxy) hexane was mixed with 0.1kg and prepared in a pellet state through a twin screw extruder. The obtained pellet was sufficiently dehumidified to prepare an inflation film having a thickness of 30 μm through a blown film extruder. Specimens were prepared from the prepared films to measure tensile strength, elongation, transparency, and resolution, and the results are shown in Table 1.

(Example 2)

Except for using 1kg of nanoparticles, an inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, and the tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating a specimen from the prepared film. The results are shown in Table 1.

(Example 3)

Except that 5kg nanoparticles were used, an inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, and a tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating a specimen from the prepared film. The results are shown in Table 1.

(Example 4)

An inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, except that 10 kg of aromatic-aliphatic polyester, 0.5 kg of nanoparticles, and 90 kg of polylactic acid polymer (PLA POLYMER) were prepared. Tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating specimens in Table 1, and the results are shown in Table 1.

(Example 5)

An inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, except that 50 kg of aromatic-aliphatic polyester, 0.5 kg of nanoparticles, and 50 kg of polylactic acid polymer (PLA POLYMER) were prepared. Tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating specimens in Table 1, and the results are shown in Table 1.

(Comparative Example 1)

Except that 0.05kg nanoparticles were used, an inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, and a tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating a specimen from the prepared film. The results are shown in Table 1.

(Comparative Example 2)

Except for using 15kg nanoparticles were prepared inflation film (Inflation film) of 30㎛ thickness in the same manner as in Example 1, and the tensile strength, elongation, transparency, dispersion, decomposition degree was measured by fabricating a specimen from the prepared film. The results are shown in Table 1.

(Comparative Example 3)

An inflation film having a thickness of 30 μm was prepared in the same manner as in Example 1, except that 3 kg of aromatic-aliphatic polyester, 0.5 kg of nanoparticles, and 97 kg of polylactic acid polymer (PLA POLYMER) were prepared. Tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating specimens in Table 1, and the results are shown in Table 1.

(Comparative Example 4)

An inflation film having a thickness of 30 μm was manufactured in the same manner as in Example 1, except that 70 kg of aromatic-aliphatic polyester, 0.5 kg of nanoparticles, and 30 kg of polylactic acid polymer (PLA POLYMER) were prepared. Tensile strength, elongation, transparency, dispersion, and resolution were measured by fabricating the specimen at, and the results are shown in Table 1.

Table 1

  division Furtherance Properties Aromatic-aliphatic polyester  MMT-25A  Polylactic acid Tensile Strength (Kg / cm ² )  % Elongation  transparency  Exploded view MD TD MD TD Example-1 40 0.5 60 3.8 3.4 340 330 2 One Example-2 40 1.0 60 4.1 3.4 320 350 2 One Example-3 40 5.0 60 4.2 3.6 350 260 2 One Example-4 10 0.5 90 5.1 4.4 290 270 One One Example-5 50 0.5 50 3.2 3.2 420 430 2 One Comparative Example-1 40 0.05 60 1.8 1.9 290 300 2 One Comparative Example-2 40 15 60 2.3 2.4 300 250 3 One Comparative Example-3 3 0.5 97 5.1 4.9 180 190 One One Comparative Example-4 70 0.5 30 1.8 1.7 460 450 3 One

(The aromatic component of the aromatic-aliphatic polyester is 30 mol%)

As can be seen in Table 1, the biodegradable polyester resin composition according to the present invention does not inhibit the advantages of the two degradable polyesters having different structures and pros and cons, and the nanoparticles in the composition that can compensate for the disadvantages. It is a biodegradable resin composition with excellent practical value because it can be applied to various applications by further enhancing physical properties through excellent dispersion of.

Claims (9)

A biodegradable polyester resin composition comprising 40 to 95 parts by weight of polylactic acid, 5 to 60 parts by weight of aromatic-aliphatic polyester, and 0.1 to 10 parts by weight of nanoparticles based on 100 parts by weight of the mixed composition. The method of claim 1, The polylactic acid is selected from the group consisting of L-lactic acid, D-lactic acid and L, D-lactic acid, alone or in combination, characterized in that the molecular weight of 10,000 or more biodegradable polyester resin composition. The method of claim 1, The aromatic-aliphatic polyester may comprise at least one aromatic component selected from the group consisting of dicarboxylic acids having a structure of ROOC-Ar-COOR '(R, R' is hydrogen or an alkyl group) and derivatives thereof; At least one aliphatic component selected from the group consisting of dicarboxylic acids having a structure of ROOC- (CH ₂ ) n-COOR '(R, R' is hydrogen or an alkyl group, n is 2 to 14) and derivatives thereof; And a diol having a structure of HO- (CH ₂ ) n-OH (n is 2 or more), a polyalkylene glycol, and an aliphatic dihydric alcohol having a structure represented by the general formula (1). Biodegradable polyester resin composition, characterized in that configured by the reaction. General formula (1) HO-R ₁ -OH    | R ₂ In said general formula (1), R <_1> is a C2-C8 alkylene group and R <_2> is a C2-C8 alkyl group. The method of claim 1, The nanoparticles are biodegradable polyester resin composition, characterized in that selected from the group consisting of clay, inorganic nanoparticles, organic polymer nanoparticles and metal particles. The method of claim 4, wherein The clay is selected from the group consisting of montmorilonite, bentonite, hectorite, saponite, atapulgite, sepiiorite and vermiculite, the weapon The nanoparticles are selected from the group consisting of silica sol, titania sol and alumina sol, and the metal particles are selected from the group consisting of palladium, platinum, gold and silver. The method of claim 4, wherein The clay constituting the nanoparticles is a biodegradable polyester composition, characterized in that the surface is modified. The method of claim 1, The resin composition is a biodegradable polyester composition, characterized in that it comprises a shape of a film, fiber or molded body. The biodegradation of claim 1 comprising mixing the nanoparticles in a solvent dispersed state in the aromatic-aliphatic polyester polymerization process and synthesizing the aromatic-aliphatic polyester including the nanoparticles by polylactic acid and compounding. A method of producing a polyester resin composition. The method of claim 8, The solvent used in the step of mixing the nanoparticles dispersed in a solvent is glycols such as ethylene glycol, propylene glycol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4 Selected from the group of alkylene glycols consisting of cyclohexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, neopentylglycol, propylene glycol and tetramethylene glycol A method of producing a biodegradable polyester resin composition, characterized in that at least one.