Resin composition and biodegradable resin product comprising the same

Abstract

This invention relates to resin compositions and biodegradable molded resin articles comprising the resin compositions. The resin compositions of this invention can achieve suitable adhesion, mechanical properties, and permeability for packaging applications while maintaining the biodegradability of polybutylene adipate terephthalate.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0070233, filed on May 29, 2024, and all contents disclosed in the aforementioned Korean patent application are incorporated herein by reference and form part of this specification. Technical Field

[0003] This invention relates to resin compositions and biodegradable resin molded articles comprising the resin compositions. Background Technology

[0004] Recent frequent natural disasters have highlighted environmental pollution and the resulting climate change as serious issues that must be addressed as a top priority. Reducing the use of single-use plastics is one environmental pollution mitigation activity that can be implemented in daily life, and countries are adopting it as policy. As part of these policies, the use of eco-friendly or biodegradable plastics is recommended, and various biodegradable plastics for soil or marine environments are being researched and developed.

[0005] Meanwhile, for food packaging materials, plastic films are mostly used to prevent spoilage and preserve food during distribution. Polyvinyl chloride (PVC) packaging materials are commonly used as cling film and food preservation films due to their low price and excellent packaging properties. However, PVC has problems such as generating chlorine gas during post-use processing / incineration and pollution during recycling. Furthermore, the government is strengthening regulations on the use of PVC cling film to improve the quality of recycled products and reduce the emission of harmful gases.

[0006] To replace this type of PVC packaging film, research is needed on functional, stable materials, and polyolefin (primarily LLDPE) packaging has been developed in response to this demand. However, it is difficult to achieve properties such as tackiness at levels comparable to PVC, and recycling is challenging due to the often multi-layered design used to achieve the desired properties.

[0007] Therefore, there is a need to study materials that are biodegradable and can decompose naturally in soil or marine environments, and that possess the gas barrier, mechanical, and chemical properties required for food packaging. Summary of the Invention

[0008] Technical issues

[0009] The present invention aims to provide a resin composition that satisfies the adhesiveness, mechanical properties and permeability required for packaging films, while also being biodegradable.

[0010] In addition, the present invention aims to provide a biodegradable resin molded article comprising the above-described resin composition.

[0011] Technical solution

[0012] To address the aforementioned problems, the present invention provides a resin composition comprising polybutylene adipate terephthalate (PBAT) and triacetin, wherein the weight-average molecular weight of the polybutylene adipate terephthalate is from 100,000 g / mol to 200,000 g / mol, and the resin composition comprises from 1 part to 25 parts by weight of triacetin based on a total of 100 parts by weight.

[0013] According to one example, the weight-average molecular weight of polybutylene adipate terephthalate can range from 130,000 g / mol to 190,000 g / mol.

[0014] According to one example, the polydispersity index (PDI) of polybutylene adipate terephthalate can be below 2.5.

[0015] According to one example, the melt index of polybutylene adipate terephthalate (measured according to ASTM D1238 at 190°C and 2.16 kg load) can be from 2.0 g / 10 min to 6.0 g / 10 min.

[0016] According to one example, based on a total of 100 parts by weight of resin composition, it may contain 1 to 20 parts by weight of triacetylglycerol.

[0017] In addition, the present invention provides a biodegradable resin molded article comprising the resin composition of the present invention.

[0018] According to one example, the modulus value measured according to ASTM D882 can be from 30 MPa to 100 MPa.

[0019] According to one example, the viscosity value measured according to ASTM D882 can be from 5 N to 20 N.

[0020] Based on one example, with a sheet thickness of 500 μm to 600 μm, the oxygen permeability of biodegradable resin molded articles can reach 100 cc / m². 2 • Day • ATM up to 400 cc / m 2 ·day·atm.

[0021] Based on one example, the moisture permeability of biodegradable resin molded articles can reach 50 g / m² based on sheet thicknesses of 500 μm to 600 μm. 2 · up to 95 g / m 2 ·sky.

[0022] The terminology used herein is for describing exemplary embodiments only and is not intended to limit the invention.

[0023] Unless the context clearly indicates otherwise, singular expressions include plural expressions.

[0024] In this specification, terms such as “comprising,” “having,” or “containing” are intended to describe the implemented features, quantities, steps, components, or combinations thereof, and do not exclude the possibility of one or more other features, quantities, steps, components, combinations thereof, or additions thereof.

[0025] This invention can be modified and taken in various forms, and some embodiments will be described in detail below. However, these embodiments are not intended to limit the invention to any particular form of disclosure, and the invention should be understood to include all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0026] The present invention will now be described in detail.

[0027] The present invention provides a resin composition comprising polybutylene terephthalate (PBAT) and triacetin, wherein the weight-average molecular weight of the polybutylene terephthalate is from 100,000 g / mol to 200,000 g / mol, and the resin composition comprises 1 to 25 parts by weight of triacetin based on a total of 100 parts by weight.

[0028] Polyester resins are used in various industrial fields due to their excellent mechanical and chemical properties. Among them, polybutylene terephthalate (PBAT) is a soft, biodegradable polyester, and therefore has attracted attention as an alternative to polyolefin polymers mainly used in food packaging films. However, the use of soft PBAT alone in these applications suffers from some shortcomings in PBAT's viscosity and gas barrier properties.

[0029] As part of research into using biodegradable resin-type polybutylene terephthalate (PBAT) as a packaging material, the inventors conducted studies on its blending with various additives and confirmed that when triacetin is used in the additives, it exhibits excellent miscibility with PBAT.

[0030] Specifically, the inventors used the Hansen solubility parameters of polybutylene terephthalate (PET) and additives to select a group of substances predicted to have high miscibility with PET. Then, a resin composition was prepared by mixing the PET with the additives, and the migration properties of the additives were evaluated. The results showed that the excellent miscibility of triacetin ester with PET was confirmed experimentally.

[0031] Triacetin is a compound represented by the following chemical formula 1, which is a triester of glycerol and acetic acid: [Chemical Formula 1]

[0032] Furthermore, when the weight-average molecular weight of polybutylene adipate terephthalate is 100,000 g / mol to 200,000 g / mol, the mechanical properties such as modulus, strength, and elongation of the resin composition blended with triacetyl ester and polybutylene adipate terephthalate are improved. The viscosity is improved relative to 1 to 25 parts by weight of triacetyl ester in a total of 100 parts by weight of resin composition, and it is found that appropriate oxygen permeability and moisture permeability can be achieved, thereby completing the present invention.

[0033] The resin composition of the present invention comprises polybutylene adipate terephthalate (PBT) with a weight-average molecular weight of 100,000 g / mol to 200,000 g / mol. If the weight-average molecular weight of PBT is less than 100,000, it is difficult to extrude due to its low melt viscosity, and problems with low modulus, strength, and elongation may occur when manufacturing molded articles, thus failing to achieve suitable mechanical properties for the application. Furthermore, if the weight-average molecular weight of PBT exceeds 200,000 g / mol, the modulus, strength, etc., may increase to levels unsuitable for use as food packaging materials. Preferably, the weight-average molecular weight of PBT can be 110,000 g / mol or more, 120,000 g / mol or more, or 130,000 g / mol or more, and can be 200,000 g / mol or less, or 190,000 g / mol or less.

[0034] Furthermore, based on a total of 100 parts by weight of the resin composition, the resin composition of the present invention may contain 1 to 25 parts by weight of triacetyl ester. If the total of 100 parts by weight of the resin composition contains less than 1 part by weight of triacetyl ester, the improvement in viscosity due to the addition of triacetyl ester may be insignificant, and therefore may not be suitable for the purposes of the present invention. Furthermore, if the total of 100 parts by weight of the resin composition contains more than 25 parts by weight of triacetyl ester, migration of triacetyl ester may occur during the preparation of the blended resin composition due to excessive use of triacetyl ester. Preferably, based on a total of 100 parts by weight of the resin composition, it may contain 1 or more, 3 or more, 5 or more, 7 or more, or 10 or more parts by weight of triacetyl ester, and less than 23 parts by weight, less than 22 parts by weight, or less than 20 parts by weight. For example, based on a total of 100 parts by weight of the resin composition, it may contain 1 to 20 parts by weight, or 5 to 20 parts by weight, or 10 to 20 parts by weight of triacetyl ester.

[0035] In addition, in this invention, the polydispersity index (PDI) of polybutylene adipate terephthalate can be 2.5 or less.

[0036] In addition, the melt index of polybutylene adipate terephthalate (measured according to ASTM D123 at 190°C and 2.16 kg load) can be from 2.0 g / 10 min to 6.0 g / 10 min.

[0037] When the polydispersity index and / or melt index of polybutylene adipate terephthalate (PBAT) meet the above-mentioned ranges, its miscibility with triacetin is improved, allowing for the preparation of a homogeneous resin composition. Furthermore, when manufacturing molded articles containing this resin composition, surface defects can be reduced, while processability and productivity are improved. Specifically, the melt index of PBAT (measured according to ASTM D123 at 190°C and a 2.16 kg load) can be ≥2.0 g / 10 min, ≥2.3 g / 10 min, or ≥2.5 g / 10 min, and can be ≤5.7 g / 10 min, ≤5.5 g / 10 min, ≤5.3 g / 10 min, or ≤5.0 g / 10 min.

[0038] Furthermore, the resin composition according to the present invention may contain only polybutylene adipate and triacetin as resin components. That is, the resin composition of the embodiments of the present invention may preferably not contain any other resin or polymer components other than polybutylene adipate. For example, based on a total of 100 parts by weight of the resin composition, the resin composition according to the present invention may contain 1 to 25 parts by weight of triacetin, with the remainder being polybutylene adipate, but the present invention is not limited thereto.

[0039] Furthermore, if desired, the resin composition of the present invention may further comprise other additives. As additives, commonly used additives in the molding of resin compositions within the technical field to which this invention pertains can be used without particular limitation. Additives may include heat stabilizers, UV stabilizers, etc.

[0040] Furthermore, according to another aspect of the present invention, a biodegradable resin molded article comprising the above-described resin composition is provided. The biodegradable resin molded article may be a biodegradable film.

[0041] According to one embodiment of the invention, the biodegradable resin molded article can have a modulus value of 30 MPa to 100 MPa as measured according to ASTM D882. If the modulus value is less than 30 MPa, it may be inconvenient to use as a packaging material, and if it exceeds 100 MPa, the cutability may deteriorate. Preferably, the modulus value can be 30 MPa or more, 31 MPa or more, 32 MPa or more, or 33 MPa or more, and can be 95 MPa or less, 90 MPa or less, or 85 MPa or less.

[0042] According to one embodiment of the invention, the biodegradable resin molded article may have a viscosity value of 5 N to 20 N as measured according to ASTM D882. When the viscosity of the biodegradable resin molded article meets the above range, it is suitable for use as a food packaging material. Preferably, the viscosity value may be 5 N or more and 19 N or less, 18 N or less, 17 N or less, or 16 N or less.

[0043] According to one embodiment of the present invention, based on a sheet thickness of 500 μm to 600 μm, the oxygen permeability of the biodegradable resin molded article can be 100 cc / m³. 2 sky atm up to 400 cc / m 2 sky atm. Preferably, the oxygen permeability can be 150cc / m. 2 sky above 200cc / m 2 sky above 1.5m, or 230cc / m 2 sky above atm, and can be 370cc / m 2 sky below atm, 350cc / m 2 sky below atm, 330cc / m 2 sky Below atm, or 270cc / m 2 sky Below atm. Oxygen permeability was measured at 23°C and RH 0%, and the specific measurement method is detailed in the examples described later.

[0044] According to one embodiment of the present invention, based on a sheet thickness of 500 μm to 600 μm, the moisture permeability of the biodegradable resin molded article can be 50 g / m². 2 95g / m 2 Preferably, the moisture permeability can be 55 g / m³. 2 More than 1 day, 60g / m 2 More than 1 day, 65g / m 2 More than 70g / m 2 More than 75g / m 2 More than 1 day, 80g / m 2 More than 1 day, or 85g / m 2 More than 1 day, and can be 90g / m 2 Below 100 days. The moisture permeability was measured at 38°C and 90% RH, and the specific measurement method can be detailed in the examples described later.

[0045] According to an example of the invention, the biodegradable resin molded article can be used in applications such as food packaging materials due to its excellent viscosity, mechanical properties and gas permeability.

[0046] Technical effect

[0047] As described above, the resin composition of the present invention can achieve adhesiveness, mechanical properties and permeability suitable for packaging material applications while maintaining the biodegradability of polybutylene adipate terephthalate. Detailed Implementation

[0048] Preferred embodiments are given below to aid in understanding the invention. However, the following examples are for illustrative purposes only and are not intended to limit the invention to these embodiments.

[0049] Example

[0050] Preparation of resin composition 1

[0051] The resin composition was prepared according to the composition in Table 1 below. Specifically, polybutylene adipate terephthalate was dried at 80°C. The resin composition was prepared by heating a brabender (Brabender Co.) mixer to 190°C, adding 83.3 parts by weight of dried polybutylene adipate terephthalate and 16.7 parts by weight of the additives listed in Table 1 below to a total of 100 parts by weight of the resin composition, and mixing at 190°C for 6 minutes.

[0052] The polybutylene adipate terephthalate used has a weight-average molecular weight of 130,000 g / mol and a polydispersity index (PDI) of 2.5 (MI = 5.0 g / 10 min @ 190 °C, 2.16 kg).

[0053] Property Evaluation

[0054] The prepared resin composition was evaluated for melt temperature (Tm), tensile strength, elongation and migration, and the results are shown in Table 1 below.

[0055] 1) Melting temperature (Tm)

[0056] • Differential scanning calorimetry (DSC, TA DSC250) was used; • -60℃ to 200℃, heating rate 10℃ / min, thermal property analysis using Trios S / W; • Prepare a resin composition of about 5 mg to 10 mg, compact it in a tray, load it, and then measure it.

[0057] 2) Tensile strength and elongation

[0058] • Use a hot press from Wabash Co.; • Sheets of 500 μm to 600 μm were prepared by pressing at 190°C for 3 minutes and then at 30°C for 2 minutes. • Use test / measurement standards and samples conforming to ASTM D882, and measure at a speed of 500 mm / min.

[0059] 3) Migration evaluation

[0060] The prepared resin composition was cooled to room temperature and evaluated one day after cooling by wiping it with tissue paper to determine whether the additives had been transferred onto the tissue paper.

[0061] Table 1

[0062] 1) LG CHEM GL500 (a mixture of dibutyl 1,4-phthalate and di(2-ethylhexyl) 1,4-phthalate)

[0063] 2) Epoxidized soybean oil (Product name: 412333, Manufacturer: Sigma Aldrich)

[0064] Preparation of resin composition 2

[0065] The resin composition was prepared according to the composition shown in Table 2 below. Specifically, after drying polybutylene adipate at 80°C, the polybutylene adipate and triacetin were uniformly mixed with each other according to the composition shown in Table 2, relative to a total of 100 parts by weight of the resin composition. The mixture was then fed into a twin-screw extruder (EM Co., Korea, Φ=32mm, L / D=40~44) heated to 170°C, and extruded under extrusion conditions of 170°C, 10kg / hr, and 200rpm to prepare the resin composition.

[0066] Table 2

[0067] Property Evaluation

[0068] The prepared resin composition or sheets or films containing it were evaluated for modulus, strength, elongation, migration and tack, and the results are shown in Table 3 below.

[0069] 1) Modulus, strength, and elongation of the pressed sample

[0070] • Use a hot press from Wabash Co.; • Sheets of 500 μm to 600 μm were prepared by pressing at 190°C for 3 minutes and then at 30°C for 2 minutes. • Use test / measurement standards and samples conforming to ASTM D882, and measure at a speed of 500 mm / min.

[0071] 2) Modulus, strength, and elongation of membrane samples

[0072] • Use casting film equipment from Eurexma Co.; • Films with a thickness of less than 100 μm were prepared at an extrusion temperature of 150 °C to 170 °C and an extrusion speed of 60 rpm to 90 rpm. • Use test / measurement standards and samples conforming to ASTM D882, and measure at a speed of 500 mm / min.

[0073] 3) Migration

[0074] The prepared resin composition was cooled at room temperature and evaluated with tissue paper one day after cooling to determine whether the additives had been transferred to the tissue paper.

[0075] 4) Viscosity

[0076] • Use casting film equipment from Eurexma Co.; • Films with a thickness of less than 100 μm were prepared at an extrusion temperature of 150 °C to 170 °C and an extrusion speed of 60 rpm to 90 rpm. • Prepare two films by cutting them into 13mm wide and 150mm long pieces; overlap the middle 50mm portion of each film and press with 1kg for 3 minutes; • A tensile testing instrument from ZwickRoell Co. was used; • Measure the maximum N (Newton) value at a measurement speed of 50 mm / min according to ASTM D882 measurement standard.

[0077] Table 3

[0078] As shown in Table 3 above, compared with Comparative Example 2-1 which does not contain triacetin, the resin compositions according to the embodiments of the present invention exhibit similar tensile strength, reduced modulus, and increased elongation, thus demonstrating easy-to-cut properties. Meanwhile, it was confirmed that Comparative Example 2-2, in which the molecular weight of PBAT is lower than that of PBAT contained in the resin compositions of the present invention, has very low tensile properties compared to conventional PBAT, making it unsuitable for packaging.

[0079] Barrier performance evaluation

[0080] Using the preparation method for resin composition 1, a resin composition was prepared with the composition in Table 4 below, and then prepared into a sheet. The oxygen permeability and moisture permeability were then measured and are shown in Table 4 below.

[0081] 1) Sheet preparation

[0082] • Use a hot press from Wabash Co.; • Sheets of 500 μm to 600 μm were prepared by pressing at 190°C for 3 minutes and then at 30°C for 2 minutes.

[0083] 2) Oxygen permeability

[0084] • An oxygen permeability tester from Systech Illinois Co. (8001) was used; • Use 5cm 2 Circular sheets of various sizes; • Oxygen (>99.9%) supply pressure 1.5 bar, relative humidity 0%, measurement temperature 23°C, measured at 15-minute intervals for 48 hours.

[0085] 3) Moisture permeability

[0086] -Used a moisture permeability tester from Systech Illinois Co. Aquasense (7101); -Use 5cm 2 Circular sheets of various sizes; - Nitrogen (carrier gas) supply pressure 2 bar, relative humidity 90%, measurement temperature 23°C, measured at 10-minute intervals for 48 hours.

[0087] Table 4

[0088] 1) PVC (Manufacturer: Power Lab Co., Ltd., Product Name: Cling Wrap)

[0089] As shown in Table 4 above, it was confirmed that the resin composition of the embodiments of the present invention had increased oxygen permeability and moisture permeability compared with Comparative Example 3-1 which did not contain triacetyl ester, and had lower oxygen permeability and higher moisture permeability compared with conventional packaging PVC and Comparative Example 3-3 which contained a high content of triacetyl ester, thus confirming its high potential as a breathable membrane.

Claims

1. A resin composition comprising polybutylene adipate (PBAT) and triacetin, wherein the PBAT has a weight-average molecular weight of 100,000 g / mol to 200,000 g / mol, and wherein 1 to 25 parts by weight of the triacetin are contained in a total of 100 parts by weight of the resin composition.

2. The resin composition according to claim 1, wherein, The weight-average molecular weight of the polybutylene adipate terephthalate is from 130,000 g / mol to 190,000 g / mol.

3. The resin composition according to claim 1, wherein, The polydispersity index (PDI) of the polybutylene adipate terephthalate is below 2.

5.

4. The resin composition according to claim 1, wherein, The melt index of the polybutylene adipate terephthalate, measured according to ASTM D1238 at 190°C and 2.16 kg load, is 2.0 g / 10 min to 6.0 g / 10 min.

5. The resin composition according to claim 1, wherein, Based on a total of 100 parts by weight of the resin composition, the resin composition comprises 1 to 20 parts by weight of the triacetylglycerol.

6. A biodegradable resin molded article comprising the resin composition according to any one of claims 1 to 5.

7. The biodegradable resin molded article according to claim 6, wherein, The modulus value, as determined by ASTM D882, ranges from 30 MPa to 100 MPa.

8. The biodegradable resin molded article according to claim 6, wherein, The viscosity value, as determined by ASTM D882, ranges from 5 N to 20 N.

9. The biodegradable resin molded article according to claim 6, wherein, Based on a sheet thickness of 500 μm to 600 μm, the oxygen permeability of the biodegradable resin molded article is 100 cc / m². 2 • Day • ATM up to 400 cc / m 2 ·day·atm.

10. The biodegradable resin molded article according to claim 6, wherein, Based on a sheet thickness of 500 μm to 600 μm, the moisture permeability of the biodegradable resin molded article is 50 g / m². 2 · up to 95 g / m 2 ·sky.