KR102460340B1 - Biodegradable polyester resin composition - Google Patents

Abstract

The present invention relates to a biodegradable polyester resin composition with improved tear growth resistance and a film manufactured using the same. According to the present invention, elongation including tear growth resistance, tensile strength, It has excellent mechanical properties such as thermal adhesive strength and can overcome problems in use due to the low physical properties of the biodegradable aliphatic polyester resin composition. It is expected that it can be expanded.

Description

Biodegradable polyester resin composition {BIODEGRADABLE POLYESTER RESIN COMPOSITION}

The present invention relates to a biodegradable polyester resin composition having significantly improved tear growth resistance and a film prepared using the same.

As the usage of plastic products rapidly increases, the problem of environmental pollution due to disposal after use is serious. Accordingly, biodegradable polyester resins are being actively developed for application to various fields such as various containers and packaging paper. These biodegradable polyester resins are environmentally friendly because they exhibit biodegradability that is decomposed into low-molecular substances due to the enzymatic action of microorganisms present in the environment, and finally decomposed into water and carbon dioxide.

Although polylactic acid (PLA) is a biodegradable material that is currently being put into practical use, it has low tear strength and elongation, and has problems in that it is easily damaged by impact, thereby limiting its application to various fields. In addition, polylactic acid has poor bubble stability, which causes a problem in that a hole is formed in a portion having a reduced thickness during blow molding for manufacturing a film. In addition, when a high content of PLA (more than 30%) is prescribed, the deterioration of the tear growth resistance is noticeable. The blow molding is a process widely used commercially because of its high production rate and low cost, but commercialization and commercialization are impossible due to the limitations of blow molding of polylactic acid.

As an example of research to solve the problems of polylactic acid, low physical properties of polylactic acid by blending with other polyester resins with high tear strength and elongation, such as polybutylene adipate terephthalate (PBAT) ways to improve it. However, the polybutylene adipate terephthalate copolymer has very low compatibility with polylactic acid, so it is difficult to achieve desired physical properties, so that the problems of polylactic acid cannot be improved, and the film prepared therefrom is easily torn. Moreover, in this case, the deterioration of the tear growth resistance could not be solved.

As another example, an aliphatic/polyester/resin composition containing succinic acid or adipic acid, or both thereof and a diol component as main structural units, and a method for manufacturing the same. The film manufactured from this is flexible, has high elongation and impact resistance, and has excellent heat seal properties, so it can be used in a bag shape. However, the aliphatic polyester is difficult to suppress the growth of crystals and becomes opaque even if it is rapidly cooled immediately after melt-extrusion. In addition, when the film is too flexible to print or laminate another film, paper, metal thin film, etc. on this film, the film is pulled and stretched during the process, so there are problems such as inconsistent printing or inability to uniformly laminate.

Therefore, in the environmentally friendly biodegradable polyester resin composition, it is still necessary to study an innovative alternative that can solve the economic feasibility while retaining excellent mechanical properties.

KR 10-2001-0057068 A

It is an object of the present invention to provide a biodegradable polyester resin composition having improved mechanical properties, in particular, tear growth resistance, and a film prepared using the same.

Specifically, it does not cause deterioration of tear growth resistance even when high content polylactic acid is prescribed, and mechanical properties such as elongation, tensile strength, and thermal adhesive strength can be maintained and improved without lowering the biodegradability of the biodegradable film. and to provide a biodegradable polyester resin composition capable of shortening the processing time by having a melt flow index suitable for processing, and a film prepared using the same.

In order to solve the above problems, the present invention provides a biodegradable polyester resin composition comprising an acid anhydride-modified biodegradable aliphatic polyester and an acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the weight ratio of the acid anhydride-modified biodegradable aliphatic polyester and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer is 3:7 to 7: can be 3

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride may be maleic anhydride.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer may satisfy Equation 1 below.

[Formula 1]

0.1≤ MI _A /MI _A0 < 1.0

[In Equation 1 above,

MI _A0 is the melt flow index of the biodegradable aliphatic-aromatic polyester copolymer before modification,

MI _A is the melt flow index of the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer,

The melt flow index is measured according to ASTM D1238 at 190 °C and a load of 2.16 kg.]

The biodegradable polyester resin composition according to an embodiment of the present invention satisfies Equation 1 above, and melt flow of the acid anhydride-modified biodegradable aliphatic polyester and acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer The index ratio (MI _B /MI _A ) may be 1 to 4.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the biodegradable aliphatic polyester may be a polylactic acid-based polymer.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the biodegradable aliphatic-aromatic polyester copolymer may be a polybutylene adipate terephthalate copolymer.

The biodegradable polyester resin composition according to an embodiment of the present invention may further include a non-spherical inorganic filler.

The biodegradable polyester resin composition according to an embodiment of the present invention may further include an additive selected from an antioxidant, a peroxidizer, and a lubricant.

In addition, the present invention provides a film produced using the biodegradable polyester resin composition described above.

According to the present invention, compared to the conventional biodegradable aliphatic polyester resin composition, mechanical properties such as elongation including tear growth resistance, tensile strength, and thermal adhesion strength are excellent, and the use due to the low physical properties of the conventional biodegradable aliphatic polyester resin composition It can overcome the problem and has the advantage of not causing environmental pollution as it is completely biodegradable in a natural state.

Furthermore, the biodegradable polyester resin composition according to the present invention exhibits no deterioration in tear growth resistance and excellent blow moldability even when a high content PLA of 30% or more is prescribed, and thus has excellent productivity and application potential. In addition, the melt flow index is suitable for processing, so the processing time for film production can be shortened, and the biodegradability of the biodegradable film is not lowered, and the mechanical properties, which were previously weak, can be maintained and improved. It is expected that its use can be expanded in general.

Hereinafter, a biodegradable polyester resin composition having improved tear growth resistance according to the present invention will be described in detail. At this time, unless there are other definitions in the technical terms and scientific terms used, it has the meaning commonly understood by those of ordinary skill in the technical field to which this invention belongs, and in the following description, it may unnecessarily obscure the subject matter of the present invention. Descriptions of possible known functions and configurations will be omitted.

As used herein, the singular form may also be intended to include the plural form unless the context dictates otherwise.

In addition, in the present specification, the unit used without special mention is based on the weight, for example, the unit of % or ratio means weight % or weight ratio, and weight % means any one component of the entire composition unless otherwise defined. It means % by weight in the composition.

In addition, the numerical range used herein includes the lower limit and upper limit and all values within the range, increments logically derived from the form and width of the defined range, all values defined therein, and the upper limit of the numerical range defined in different forms. and all possible combinations of lower limits. Unless otherwise defined in the specification of the present invention, values outside the numerical range that may occur due to experimental errors or rounding of values are also included in the defined numerical range.

As used herein, the term "comprises" is an open-ended description having a meaning equivalent to expressions such as "comprises", "contains", "has" or "characterizes", and is an element not listed further; Materials or processes are not excluded.

As used herein, the term “biodegradable” may mean being decomposed by microorganisms or water.

In general, a formulation containing a high content of aliphatic polyester has a problem of rapidly lowering the tear growth resistance of the blow film due to high crystallinity. In order to overcome such problems, the present inventors have completed the present invention as a result of intensive studies.

Hereinafter, the present invention will be specifically described.

The biodegradable polyester resin composition according to an embodiment of the present invention includes a resin mixture comprising an acid anhydride-modified biodegradable aliphatic polyester and an acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer.

The biodegradable polyester resin composition according to the present invention can implement improved mechanical properties without deterioration of the tear growth resistance of a blow film employing the same, despite a prescription containing a high content of aliphatic polyester. In addition, the biodegradable polyester resin composition according to the present invention has the advantage of maintaining and improving mechanical properties that were conventionally weak without lowering the degree of biodegradation.

In addition, the biodegradable polyester resin composition according to the present invention has a melt flow index suitable for processing. That is, the biodegradable polyester resin composition according to the present invention has excellent compatibility between each polymer included therein.

Specifically, in the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride-modified biodegradable aliphatic polyester and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer are crosslinked with an acid anhydride Alternatively, it may be grafted or chain-exchanged by transesterification.

For example, the polylactic acid modified with maleic anhydride, which may be an aspect of the acid anhydride-modified biodegradable aliphatic polyester, may be represented by mPLA, and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer The polybutylene adipate terephthalate copolymer modified with maleic anhydride which may be an aspect may be denoted as mPBAT.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the resin mixture may include 30% by weight or more of the acid anhydride-modified biodegradable aliphatic polyester with respect to the total weight. Here, the balance includes the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer.

For example, the weight ratio of the acid anhydride-modified biodegradable aliphatic polyester and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer is 3:7 to 7:3, or 3:7 to 6:4, or 3: 7 to 5:5. When the above-described weight ratio is satisfied, mechanical properties such as elongation including tear growth resistance, tensile strength, and thermal bonding strength are given. In particular, it is good that a surprisingly improved advantage can be imparted to the tear growth resistance in the width direction.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride may be maleic anhydride. A biodegradable polyester resin composition comprising a resin mixture having a biodegradable aliphatic polyester and a biodegradable aliphatic-aromatic polyester copolymer modified therefrom has a melt flow index suitable for processing, but does not satisfy both. In this case, the melt flow index is rather low or high, which is undesirable because it causes a problem of incompatibility.

For example, the melt flow index of the biodegradable polyester resin composition preferably satisfies the range of 3.6 to 6.0 g/10 min, or 3.7 to 5.5 g/10 min, or 3.8 to 5.0 g/10 min. may be satisfied with

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer may satisfy Equation 1 below.

[Formula 1]

0.1≤ MI _A /MI _A0 < 1.0

[In Equation 1 above,

MI _A0 is the melt flow index of the biodegradable aliphatic-aromatic polyester copolymer before modification,

MI _A is the melt flow index of the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer,

The melt flow index is measured according to ASTM D1238 at 190 °C and a load of 2.16 kg.]

The acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer satisfying Equation 1 may be cross-linked or grafted with an acid anhydride, whereby the molecular weight may slightly increase. According to such structural characteristics, the volume fraction of the crystal structure is reduced compared to the biodegradable aliphatic-aromatic polyester copolymer before the modification of the linear structure, and the mobility of the chain existing in the amorphous structure can be increased. In addition, it is preferably located at the interface of the sea-island structure to minimize the occurrence of voids, further maximize compatibility between resin mixtures, and improve toughness. Accordingly, mechanical properties such as elongation and tensile strength as well as tear growth resistance are further improved.

In the biodegradable polyester resin composition according to an embodiment of the present invention, Equation 1 (MI _A /MI _A0 ) preferably satisfies the range of 0.2 to 0.8, or 0.3 to 0.7, or 0.4 to 0.7.

As an example, the acid anhydride-modified aliphatic-aromatic polyester copolymer may be to compensate for the low physical properties of the acid anhydride-modified biodegradable aliphatic polyester, and only by these combinations can contain a high content aliphatic polyester In addition to being able to solve the problem that the tear growth resistance of the blow film is rapidly lowered even in prescription, a more dramatic effect can be exhibited when an acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer satisfying Equation 1 above is employed. It was confirmed with an example.

For example, the aliphatic-aromatic polyester copolymer may have 6 to 30 carbon atoms in total of the repeating unit containing an aromatic substituent.

For example, the aliphatic-aromatic polyester copolymer may have a melt flow index (MI _A0 ) of 3 to 8 g/10 min, or 3 to 7 g/10 min, or 3 to 6 g/10 min. In addition, the number average molecular weight may be 10,000 to 500,000 g/mol, specifically 20,000 to 100,000 g/mol.

For example, the aliphatic-aromatic polyester copolymer is a polybutylene adipate-co-terephthalate (PBAT) copolymer and a polybutylene adipate-butylene succinate terephthalate copolymer (polybutylene adipate-co). -butylene succinate terephthalate, PBAST) may be exemplified, and polybutylene adipate terephthalate copolymer is preferably included in order to implement a synergistic effect on tear growth resistance.

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride-modified biodegradable aliphatic polyester may be a chain exchange, and the molecular weight may be somewhat reduced by such chain exchange.

For example, the biodegradable aliphatic polyester may have 2 to 15 carbon atoms in the aliphatic repeating unit.

As an example, the melt flow index (MI _B0 ) of the biodegradable aliphatic polyester may be 2 to 6 g/10 min, or 2 to 4 g/10 min, or 2.5 to 3.5 g/10 min. In addition, the weight average molecular weight may be 10,000 to 1,00,000 g/mol, specifically 50,000 to 500,000 g/mol.

For example, the biodegradable aliphatic polyester may be a polylactic acid-based polymer that is inexpensive and has excellent heat resistance and transparency, and a polylactic acid homopolymer or a copolymer with alpha-hydroxy acid (AHA), etc. can be exemplified as

In the biodegradable polyester resin composition according to an embodiment of the present invention, the acid anhydride-modified biodegradable aliphatic polyester satisfying Equation 1 above and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer are melted The flow index ratio (MI _B /MI _A ) may be 1 to 4. or 2 to 3.5, or 2 to 3.

Of course, the biodegradable polyester resin composition according to the present invention may be used without limitation as long as it is an additive that is obviously used in the art. Examples of the additives include plasticizers, viscosity modifiers, inorganic fillers, antioxidants, amide-based waxes, pigments, flame retardants, antistatic agents, antibacterial agents, biodegradation accelerators, heat stabilizers, light stabilizers, weathering stabilizers, UV absorbers and anti-blocking agents. Any one or two or more can be mentioned. Here, each of the additives may be independently mixed in an amount of 0.01 to 15 parts by weight based on 100 parts by weight of the resin mixture.

In terms of imparting a synergistic effect to the desired tear growth resistance in the present invention, a non-spherical inorganic filler may be used as an additive. In this case, slightly improved mechanical properties can be given compared to the spherical inorganic filler, and when the non-spherical inorganic filler is used together with the spherical inorganic filler, it is preferable that the amount of the non-spherical inorganic filler is at an equivalent level or more.

For example, non-limiting examples of the inorganic filler include calcium carbonate (CaCO ₃ ), talc, wollastonite, magnesium carbonate, clay, bentonite, silica (SiO ₂ ) and alumina (Al ₂ O ₃ ) It may be one or two or more selected from the like.

For example, the non-spherical inorganic filler may be of a plate shape or a random type, and by including it, it is possible to provide more advantages in tensile strength, elongation, and the like. Here, the length of the long axis of the non-spherical inorganic filler may be 1 to 50 μm, or 1 to 20 μm, or 1 to 10 μm, but is not limited thereto.

In addition, the biodegradable polyester resin composition according to the present invention may further include an additive selected from antioxidants, peroxidizers and lubricants in addition to the above-mentioned non-spherical inorganic fillers.

For example, the antioxidant may be used without limitation as long as it functions as a radical scavenger and the thermal decomposition agent, and may be exemplified by a phenol-based compound, an aromatic amine-based compound, or a phosphorus-based compound.

As an example, the biodegradable polyester resin composition according to the present invention comprises one or two or more first antioxidants selected from phenol-based compounds and aromatic amine-based compounds, and one or more second antioxidants selected from phosphorus-based compounds. The mixture can be used as an antioxidant. Here, the mixture is 　(3,5-di-t-butyl-4-hydrocyhydrocinnamate)methane ((3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane) and tris(2,4- It may include di-t-butylphenyl)phosphite ((Tris(2,4-di-t-butylphenyl)phosphite), and the mixture may be mixed in a weight ratio of 1:9 to 9:1.

For example, the peroxidizing agent may serve as a viscosity modifier, and non-limiting examples include dibenzoyl peroxide, 2,5-dimethyl-2.5di(t-butylperoxy)-hexane One selected from (2,5-Dimethyl-2,5 di(t-butylperoxy)-hexane), di-(2-t-butylperoxyisopropyl)benzene, etc. Or there may be two or more.

As an example, the lubricant may be used without limitation as long as it serves to prevent adhesion between the mold surface or the extruder surface and the resin and control frictional force during processing, molding and extrusion, and a non-limiting example thereof includes It may be one or two or more selected from erucamide, oleamide, stearamide, and the like.

In addition, the present invention provides a film produced using the biodegradable polyester resin composition described above. As described above, the film according to the present invention not only exhibits improved tear growth resistance even when a formulation containing a high content of biodegradable aliphatic polyester is used, but also has advantages in various mechanical properties such as tensile strength, elongation rate, and thermal adhesive strength. can provide

Specifically, the film according to an embodiment of the invention ball may have a tear growth resistance (T _TD ) in the width direction based on ASTM D 1922 that satisfies the range of 25 to 60 N/mm.

For example, the tear growth resistance (T _TD ) in the width direction of the film may satisfy a range of 25 to 50 N/mm, or 25 to 45 N/mm.

As an example, the film satisfies the above-described width direction tear growth resistance and at the same time the longitudinal direction tear growth resistance (T _MD ) satisfies the range of 6 N/mm or more, 8 N/mm or more, 8 to 30 N/mm it could be

For example, the film may have a ratio (T _TD /T _MD ) of the tear growth resistance in the width direction and the tear growth resistance in the longitudinal direction satisfies the range of 2 to 5. Alternatively, it may satisfy the range of 2 to 4.5, or 2.2 to 4.2.

In addition, according to the present invention, bubble stability is improved during processing, so that the blow moldability is very excellent, so that productivity can be increased. In the case of polylactic acid, which is a representative biodegradable aliphatic polyester, there is a problem in that there is a problem in that a hole is formed in a portion with a thin thickness during blow molding for manufacturing a film. This problem was solved.

Accordingly, according to the present invention, it is possible to prepare a film having improved mechanical properties stably through various processing methods such as extrusion or injection using the biodegradable polyester resin composition described above. Here, the film may be manufactured through a known processing method and is not limited to a specific shape and use. In addition, due to the advantages of the process, the production speed is fast and it is possible to manufacture various types of films at low cost.

Therefore, the film according to an embodiment of the present invention is characterized in that the tear growth resistance is significantly improved compared to the molded article prepared from the biodegradable aliphatic polyester or the biodegradable aliphatic-aromatic polyester copolymer. As a specific example, a film prepared from a polyester resin composition containing polylactic acid and polybutylene adipate terephthalate copolymer realizes at least 3.0 times or more of tear growth resistance in the width direction (T _TD ) and at least 1.7 times the length of the film. Directional tear growth resistance (T _MD ) can be implemented, and mechanical properties for tensile strength, elongation, and thermal bonding strength can also be provided. According to the realization of such excellent mechanical properties, the film according to the present invention can not only prevent damage due to impact, but also significantly reduce defects during processing.

Hereinafter, the biodegradable polyester resin composition according to the present invention will be described in more detail through Examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms. Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, the terminology used in the description in the present invention is only for effectively describing specific embodiments, and is not intended to limit the present invention.

(Assessment Methods)

1. Melt flow index

According to ASTM D1238, it was measured at 190°C and a load of 2.16 kg.

2. Bubble stability

When forming a film, it should be produced without shaking from side to side while continuously maintaining the bubble in an expanded state. At this time, the bubble size was not constant or the degree of shaking left and right was evaluated as follows.

◎: very stable state,

○: Slightly shaken from side to side (less than 2 cm), but in a stable state,

△: A state that can be corrected by using a bubble guide roll while shaking more than 2cm from side to side,

×: The size is also changed while shaking by 2 cm or more from side to side and is very unstable.

3. Tear growth resistance

Measured according to ASTM D 1922.

4. Tensile strength and elongation

According to 6.4 tensile strength and elongation test method of KS M 3001, the strength (kg/cm2) and elongation (%) of the sample at break were measured. The lowest value was taken after each measurement in the longitudinal direction (MD) and the transverse direction (TD) perpendicular to the longitudinal direction.

5. Thermal bonding strength

It was measured by KS M　7132.

6. Biodegradability

The amount of carbon dioxide generated in the standard sample (cellulose) and the test sample was measured and evaluated by the KS M ISO 14855-1 method for measuring aerobic biodegradability of plastics under composting conditions.

Biodegradability (%) = (amount of generated carbon dioxide / theoretical amount of carbon dioxide)*100

(Production Example 1)

For smooth modification, 3 weights of reactive monomers (Maleic anhydride, MAH) based on 100 parts by weight of polylactic acid (PLA, MI 2.8) having a weight average molecular weight of 100,000 g/mol and a D-Lactide content of 1.4% by weight Part and 1 part by weight of a peroxidizer (Di(tert-butylperoxyisopropyl)benzene) were mixed at high speed using a mixer (Super mixer, 400 rpm, 5 min). Next, it was compounded at a speed of 400rpm and 25kg/hr in a co-directional twin-screw extruder (diameter 30mm, L/D 40), and 150mesh was used for the screen mesh. After extrusion at a temperature of 200 ° C., the moisture content (105 ° C., 10 min) was dried until 500 ppm or less to prepare mPLA (MI 7.2).

(Production Example 2)

For smooth modification, 3 parts by weight of a reactive monomer (Maleic anhydride, MAH) with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT, MI 5.0) having a number average molecular weight of 40,000 g/mol 1 part by weight of a peroxidizer (Di(tert-butylperoxyisopropyl)benzene) was mixed at high speed using a mixer (Super mixer, 400 rpm, 5 min). Next, it was compounded at a speed of 400rpm and 25kg/hr in a co-directional twin-screw extruder (diameter 30mm, L/D 40), and 150mesh was used for the screen mesh. After extrusion at a temperature of 170 ° C., the moisture content (105 ° C., 10 min) was dried until 500 ppm or less to prepare mPBAT (MI 2.5).

(Example 1)

With respect to 100 parts by weight of the mixed resin comprising 40% by weight of mPLA obtained in Preparation Example 1 and 60% by weight of mPBAT obtained in Preparation Example 2, 0.6 parts by weight of lubricant, 0.2 parts by weight of antioxidant, and 10 parts by weight of inorganic filler are mixed Thus, using a co-directional twin-screw extruder (diameter 48 mm, L/D 40), extrusion molding was performed at 100 to 200 ℃ at 400 rpm to prepare a polyester resin composition in the form of pellets. After drying in an oven for 24 hours so that the moisture content was 500 ppm or less, it was molded into a 35 μm thick film using a 55 mm single screw extruder (dice diameter 100 mm, dies gap 1 mm). At this time, the temperature of the dies was 170°C, the burr was 2.8, and the film production speed was 15 m/min. It was confirmed that this was maintained stably.

The specific composition and content of Example 1 can be referred to from Table 1 below, and the results of physical properties through the evaluation method are shown in Table 2 below.

(Examples 2 to 6)

With the composition and content of Table 1 below, a biodegradable polyester resin composition was prepared through a method similar to that of Example 1. In addition, the film prepared using the prepared biodegradable polyester resin composition was checked for its physical properties through the above evaluation method, and the results are shown in Table 2 below.

(Comparative Examples 1 to 2)

A mixture comprising polylactic acid (PLA) having a weight average molecular weight of 100,000 g/mol and a D-Lactide content of 1.4% by weight and polybutylene adipate terephthalate copolymer (PBAT) having a number average molecular weight of 40,000 g/mol resin was used.

With the composition and content of Table 1 below, a biodegradable polyester resin composition was prepared through a method similar to that of Example 1. In addition, the film prepared using the prepared biodegradable polyester resin composition was checked for its physical properties through the above evaluation method, and the results are shown in Table 2 below.

(Comparative Example 3)

A mixed resin comprising mPLA obtained in Preparation Example 1 and polybutylene adipate terephthalate copolymer (PBAT) having a number average molecular weight of 40,000 g/mol was used.

With the composition and content of Table 1 below, a biodegradable polyester resin composition was prepared through a method similar to that of Example 1. In addition, the film prepared using the prepared biodegradable polyester resin composition was checked for its physical properties through the above evaluation method, and the results are shown in Table 2 below.

(Comparative Example 4)

A mixed resin containing polylactic acid (PLA) having a weight average molecular weight of 100,000 g/mol and a D-lactide content of 1.4% by weight and mPBAT obtained in Preparation Example 2 was used.

With the composition and content of Table 1 below, a biodegradable polyester resin composition was prepared through a method similar to that of Example 1. In addition, the film prepared using the prepared biodegradable polyester resin composition was checked for its physical properties through the above evaluation method, and the results are shown in Table 2 below.

Unit: parts by weight Example comparative example One 2 3 4 5 6 One 2 3 4 PLA - - - - - - 30 70 - 40 mPLA (Preparation Example 1) 40 50 50 50 30 70 - - 40 - PBAT - - - - - - 70 30 60 - mPBAT (Preparation Example 2) 60 50 50 50 70 30 - - - 60 Lubricant: Amide-based wax 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Primary antioxidant: PT 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Second antioxidant: TP 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Inorganic filler 1: Calcium carbonate 9 9 5 7 9 9 9 9 9 9 Inorganic filler 2: Talc One One 5 3 One One One One One One * Amide wax: Erucamide
* PT: (3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane
* TP: Tris(2,4-di-t-butylphenyl) phosphite
* Calcium carbonate: Spherical Ø 1~5㎛,
* Talc: non-spherical long axis 2~10㎛

melt flow index
(g/10 min) bubble
stability The tensile strength
(kgf/㎠) elongation
(%) tear growth resistance
(N/mm) thermal bonding strength
(N) MD TD MD TD MD TD Example 1 4.5 ◎ 33 16 292 280 11 32 0.8 Example 2 4.0 ○ 35 20 270 265 12 33 0.9 Example 3 4.1 ○ 33 20 266 254 15 35 0.9 Example 4 4.1 ○ 34 18 261 260 14 34 0.8 Example 5 5.0 ○ 27 14 366 247 17 40 0.9 Example 6 3.8 ○ 28 25 200 212 8 25 0.8 Comparative Example 1 5.2 ○ 26 18 320 330 10 13 1.0 Comparative Example 2 3.5 ○ 33 23 140 201 4 8 0.8 Comparative Example 3 6.3 ◎ 32 22 299 202 8 11 0.9 Comparative Example 4 3.2 ◎ 32 22 339 252 9 15 0.8

As shown in Table 2, it was confirmed that the film prepared using the biodegradable polyester resin composition according to the present invention implements remarkably improved tear growth resistance. Specifically, it was confirmed that the film of the present invention exhibits tear growth resistance in the width direction in the range of 25 to 40 N/mm, and tear growth resistance in the longitudinal direction in the range of 8 to 17 N/mm. As such, when the biodegradable polyester resin composition according to the present invention is employed, even when 30% or more of aliphatic polyester is included, a sharp decrease in tear growth resistance is not confirmed, as well as improved tear growth resistance. there was. In addition, it was confirmed that the same or more effects can be realized compared to the comparative example in tensile strength, elongation rate, and thermal bonding strength. In addition, it was confirmed that mechanical properties such as tensile strength and elongation slightly increased as the amount of the non-spherical inorganic filler increased.

In addition, the biodegradable polyester resin composition according to the present invention has excellent compatibility and excellent bubble stability as the melt flow index satisfies the range of 3.8 to 5.0 g/10 min. Accordingly, stable production is possible without shaking in a state in which bubbles are expanded during film processing, and processing time can be shortened.

On the other hand, when a composition comprising an unmodified biodegradable aliphatic polyester and a biodegradable aliphatic-aromatic polyester copolymer is employed (Comparative Example 1 and Comparative Example 2), lower tear growth resistance compared to Examples with the same amount of use seemed In addition, when a high content of aliphatic polyester was included, a sharp decrease in tear growth resistance was confirmed. Moreover, in the case of these comparative examples, the workability was not smooth due to severe swelling due to low mixing entropy.

As described above, the present invention has been described with specific matters and limited examples and comparative examples, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and the present invention is not limited to the above examples. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims described below, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (10)

acid anhydride-modified biodegradable aliphatic polyester and acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer;
The weight ratio of the acid anhydride-modified biodegradable aliphatic polyester and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer is 3:7 to 7:3, biodegradable polyester resin composition. delete According to claim 1,
The acid anhydride is
A biodegradable polyester resin composition comprising maleic anhydride. According to claim 1,
The acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer,
A biodegradable polyester resin composition that satisfies the following formula 1:
[Formula 1]
0.1≤ MI _A /MI _A0 < 1.0
In Equation 1 above,
MI _A0 is the melt flow index of the biodegradable aliphatic-aromatic polyester copolymer before modification,
MI _A is the melt flow index of the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer,
The melt flow index was measured according to ASTM D1238 at 190 °C and a load of 2.16 kg. 5. The method of claim 4,
The melt flow index ratio (MI _B /MI _A ) of the acid anhydride-modified biodegradable aliphatic polyester and the acid anhydride-modified biodegradable aliphatic-aromatic polyester copolymer is,
1 to 4, biodegradable polyester resin composition. According to claim 1,
The biodegradable aliphatic polyester,
A polylactic acid-based polymer, a biodegradable polyester resin composition. According to claim 1,
The biodegradable aliphatic-aromatic polyester copolymer is
A biodegradable polyester resin composition, which is a polybutylene adipate terephthalate copolymer. According to claim 1,
A biodegradable polyester resin composition further comprising a non-spherical inorganic filler. 9. The method of claim 8,
The biodegradable polyester resin composition further comprising an additive selected from antioxidants, peroxidizers and lubricants. 10. A film produced using the biodegradable polyester resin composition of any one of claims 1 or 3 to 9.