Resin composition and biodegradable resin molded article containing the same

Abstract

The present invention relates to a resin composition and a biodegradable resin molded article containing the same. The resin composition of the present invention uses a biodegradable polyester and can provide a resin product such as a hot seal film or a hot seal bag that is excellent in biodegradability and can achieve high seal strength even at a low temperature during hot sealing.

Description

Technical Field

[0001] The present invention relates to a resin composition and a biodegradable resin molded article containing the same.

Background Art

[0002] Thermoplastic polymer resins are excellent in mechanical and chemical properties and are used in various fields such as drinking water containers, medical applications, food wrapping paper, food containers, automotive molded articles, and agricultural vinyl.

[0003] Among thermoplastic polymer resins, polyethylene films, etc., are excellent in mechanical physical properties, harmless to the human body, and can be continuously deformed when heated, so they are widely used in hot-seal bags for food packaging, agricultural mulching films, etc.

[0004] Hot-seal bags for food packaging are widely used for vacuum packaging foods, etc., and many polyethylene films, etc., that can achieve excellent bonding strength even at low seal temperatures are used.

[0005] Agricultural films are widely used in the mulching farming method. Mulching refers to a material that covers the surface of the soil when cultivating crops. By covering the upper surface of the soil with various types of materials, the growth of weeds can be blocked, pests and diseases can be prevented, and thus the use of pesticides can be reduced. Also, the soil temperature can be easily adjusted, beneficial bacteria in the soil can be grown, soil erosion can be prevented, and the soil moisture can be maintained.

[0006] Examples of such mulching materials include leaves of crops such as rice straw and pasture grass, and polyolefin-based films, etc. Generally, synthetic resins such as polyethylene films are widely used.

[0007] However, as described above, polyethylene films, which are widely used as hot-sealing bags for food packaging and as mulching materials, do not decompose in the natural environment and have limitations in recycling. In particular, recently, plastics such as discarded polyethylene films have flowed into the sea, and it is known that they are refluxed in the sea and crushed by sunlight into very small microplastics.

[0008] Currently, it is known that such microplastics are floating in the sea in an uncountable amount of billions to hundreds of billions, which flow into the bodies of marine organisms, accumulate in the ecosystem, and affect the entire food chain.

[0009] Therefore, research on alternatives to existing thermoplastic plastics is necessary.

[0010] To solve this problem, recently, the development of mulching films made of photodegradable or biodegradable polymers has been actively attempted, but there are still problems that the degree of biodegradability is not sufficient and the mechanical properties do not reach those of existing polyethylene films.

Summary of the Invention

Problems to be Solved by the Invention

[0011] This specification aims to provide a biodegradable resin composition for resin products that can achieve high sealing strength even at low temperatures during hot sealing.

[0012] In addition, this specification aims to provide a biodegradable resin molded article containing the above resin composition.

Means for Solving the Problems

[0013] According to one aspect of the present invention, there is provided a resin composition containing polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), and maleic anhydride-modified polyolefin elastomer.

[0014] According to an embodiment of the invention, the maleic anhydride-modified polyolefin elastomer may be an ethylene-alpha olefin copolymer grafted with maleic anhydride.

[0015] According to an embodiment of the invention, the ethylene-alpha olefin copolymer may be an ethylene-alpha olefin copolymer selected from the group consisting of ethylene-1-butene, ethylene-1-pentene, ethylene-1-hexene, ethylene-1-heptene, and ethylene-1-octene, and may be one or more thereof.

[0016] According to an embodiment of the invention, the resin composition may contain about 1 to about 50 parts by weight, or about 10 to about 30 parts by weight of polylactic acid with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0017] According to an embodiment of the invention, the resin composition may contain about 0.01 to about 10 parts by weight, or about 0.1 to about 5 parts by weight, or about 0.1 to about 1 part by weight of maleic anhydride-modified polyolefin elastomer with respect to a total of 100 parts by weight of polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0018] And the resin composition may contain about 0.01 to about 10 parts by weight, or about 0.1 to 5 parts by weight of maleic anhydride-modified polyolefin elastomer with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0019] According to an embodiment of the invention, the maleic anhydride-modified polyolefin elastomer preferably has a melting point measured based on ASTM D3418 of 40°C to 60°C and a freezing point of 20°C to 35°C.

[0020] According to an embodiment of the invention, the maleic anhydride-modified polyolefin elastomer has a melt index value measured under the conditions of 190 °C and 21.6 kg based on ASTM D1238 of about 1.3 g / 10 min to about 2.0 g / 10 min, more preferably about 1.5 g / 10 min to about 2.0 g / 10 min, or even more preferably exceeding about 1.5 g / 10 min and less than about 2.0 g / 10 min.

[0021] According to an embodiment of the invention, the maleic anhydride-modified polyolefin elastomer may have a graft ratio of maleic anhydride of more than 0 wt% and less than 1 wt%, or about 0.1 wt% to about 0.9 wt%, or about 0.3 wt% to about 0.7 wt%.

[0022] On the other hand, according to another aspect of the present invention, there is provided a biodegradable resin molded article containing any of the above-described resin compositions.

[0023] And the biodegradable resin molded article may be a biodegradable film.

[0024] According to an embodiment of the invention, the biodegradable resin molded article has a tensile strength value measured based on ISO527 of about 250 kg / cm 2 ~ about 500 kg / cm 2 , or about 250 kg / cm 2 ~ about 400 kg / cm 2 , or about 300 kg / cm 2 ~ about 400 kg / cm 2 , or about 350 kg / cm 2 ~ about 380 kg / cm 2 and may be.

[0025] According to an embodiment of the invention, the biodegradable resin molded article may have an elongation at break value measured based on ISO527 of about 200% to about 600%, or about 300% to about 500%, or about 300% to 400%.

[0026] The biodegradable resin molded article may be a hot seal film.

[0027] According to one embodiment of the invention, the biodegradable resin molded article may have a hot seal initiation temperature of about 80°C to about 120°C, or about 100°C to about 120°C, or about 105°C to about 115°C, or about 105°C to about 110°C, measured under 2N conditions according to ASTM F1921.

[0028] According to one embodiment of the invention, the biodegradable resin molded article may have a seal strength of about 2N or more, or about 2N to about 10N, or about 2.5N to about 5N, measured at about 110°C according to ASTM F1921.

[0029] According to one embodiment of the invention, the biodegradable resin molded article may have a seal strength of about 3N or more, or about 3N to about 10N, or about 4N to about 5N, measured at about 114°C according to ASTM F1921.

[0030] The terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention.

[0031] The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0032] As used herein, terms such as "comprises," "comprises," or "having" are intended to describe embodied features, numbers, steps, components, or combinations thereof, but do not exclude the possibility of one or more other features, numbers, steps, components, combinations, or additions thereof.

[0033] Furthermore, in this specification, when a layer or element is referred to as being formed "on" another layer or element, it means that the layer or element is formed directly on the other layer or element, or that other layers or elements may be additionally formed between the layers, on the object, or on the substrate.

[0034] Although the present invention can have various forms with various modifications, specific embodiments will be illustrated and described in detail below. However, this does not limit the present invention to a specific disclosed form, and it should be understood that all modifications, equivalents, and alternatives included in the spirit and technical scope of the present invention are included.

[0035] Hereinafter, the present invention will be described in detail.

[0036] The inventors of the present invention have found that in a blend resin obtained by blending polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA), when a maleic anhydride-modified polyolefin elastomer is used, mechanical properties such as elongation and tensile strength are very excellent, and high bonding strength can be achieved even at a low temperature during hot sealing. Based on this finding, the present invention has been completed.

[0037] A resin composition according to one aspect of the present invention includes polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), and a maleic anhydride-modified polyolefin elastomer.

[0038] Polyester resins are excellent in mechanical and chemical properties and are used in various industrial fields. Among them, polybutylene adipate terephthalate (PBAT) is a soft polyester and is biodegradable, so it has attracted attention as an alternative to polyolefin-based polymers mainly used in packaging materials and agricultural films.

[0039] However, since the mechanical properties of PBAT are somewhat insufficient for using soft PBAT alone in such applications, it is mainly used by blending with hard polylactic acid (PLA); or PBAT is used alone and an organic filler such as carbon black is compounded and used.

[0040] However, since PBAT and PLA have very low compatibility, a compatibilizer must be used during blending.

[0041] Therefore, the resin composition according to one aspect of the present invention includes a maleic anhydride-modified polyolefin elastomer as a compatibilizer component.

[0042] According to one embodiment of the invention, the maleic anhydride-modified polyolefin elastomer may be an ethylene-alpha olefin copolymer grafted with maleic anhydride.

[0043] The ethylene-alpha olefin copolymer grafted with maleic anhydride can enhance the compatibility between PBAT and PLA in terms of its molecular structure. As a result, the resin composition according to one aspect of the present invention can achieve a very high elongation rate and tensile strength, etc., and at the same time, can achieve a high bonding strength even at a low temperature during hot sealing.

[0044] According to one embodiment of the invention, the ethylene-alpha olefin copolymer may be an ethylene-alpha olefin copolymer selected from the group consisting of ethylene-1-butene, ethylene-1-pentene, ethylene-1-hexene, ethylene-1-heptene, and ethylene-1-octene. Among them, it is most preferable to use an ethylene-1-octene copolymer grafted with maleic anhydride as a compatibilizer, but the present invention is not necessarily limited thereto.

[0045] According to one embodiment of the invention, the resin composition may include about 1 to about 50 parts by weight, or about 10 to about 30 parts by weight of polylactic acid with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0046] When the content of polylactic acid is excessively low, the effect of improving the mechanical properties of PBAT does not appear. When the content of polylactic acid is excessively high, problems such as high hardness and decreased elongation rate may occur.

[0047] According to an embodiment of the invention, the resin composition may contain about 0.01 to about 10 parts by weight, or about 0.1 to about 5 parts by weight, or about 0.1 to about 1 part by weight of maleic anhydride-modified polyolefin elastomer based on a total of 100 parts by weight of polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0048] And the resin composition may contain about 0.01 to about 10 parts by weight, or about 0.1 to 5 parts by weight of maleic anhydride-modified polyolefin elastomer based on 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0049] When the content of maleic anhydride-modified polyolefin elastomer is excessively low, the compatibility between PBAT and PLA decreases, and problems such as no blending may occur. When the content of maleic anhydride-modified polyolefin elastomer is excessively high, problems such as decreased mechanical properties and biodegradability may occur.

[0050] According to an embodiment of the invention, the maleic anhydride-modified polyolefin elastomer preferably has a melting point measured based on ASTM D3418 of 40°C to 60°C and a freezing point of 20°C to 35°C.

[0051] According to one embodiment of the invention, the maleic anhydride-modified polyolefin elastomer may have a melt index of about 1.3 g / 10 min to about 2.0 g / 10 min, more preferably about 1.5 g / 10 min to about 2.0 g / 10 min, or more than about 1.5 g / 10 min and less than about 2.0 g / 10 min, measured according to ASTM D1238 at 190°C and 21.6 kg.

[0052] According to one embodiment of the invention, the maleic anhydride modified polyolefin elastomer may have a graft ratio of maleic anhydride of more than 0 wt% and less than 1 wt%, or about 0.1 wt% to about 0.9 wt%, or about 0.3 wt% to about 0.7 wt%.

[0053] On the other hand, according to another aspect of the present invention, there is provided a biodegradable resin molded article comprising any one of the resin compositions described above.

[0054] In addition, the resin composition according to an embodiment of the present invention may further contain other additives. The additives may be any additives commonly used in molding resin compositions in the technical field to which the present invention pertains, i.e., the field of thermoplastic polymers, without any particular limitations.

[0055] The additives can include inorganic fillers, organic fillers, heat stabilizers, UV stabilizers, and the like.

[0056] The additive is contained in an amount of about 1 to about 30 parts by weight relative to a total of 100 parts by weight of polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0057] The biodegradable resin molded article may be a biodegradable film.

[0058] According to one embodiment of the invention, the biodegradable resin molded article has a tensile strength of about 250 kg / cm as measured in accordance with ISO 527. 2 ~About 500kg / cm 2 , or approximately 250 kg / cm2 ~about 400kg / cm 2 , or approximately 300 kg / cm 2 ~about 400kg / cm 2 , or approximately 350 kg / cm 2 ~Approx. 380kg / cm 2 and can have very good tensile strength values.

[0059] According to one embodiment of the invention, the biodegradable resin molded article can have an extremely excellent elongation value of about 200% to about 600%, or about 300% to about 500%, or about 300% to about 400%, as measured in accordance with ISO 527.

[0060] Due to these mechanical properties, the biodegradable resin molded article according to one embodiment of the present invention can be used for applications such as agricultural mulching films.

[0061] According to another example, the biodegradable resin molded article may be a hot seal film.

[0062] According to one embodiment of the invention, the biodegradable resin molded article may have a hot seal initiation temperature of about 80°C to about 120°C, or about 100°C to about 120°C, or about 105°C to about 115°C, or about 105°C to about 110°C, measured under 2N conditions according to ASTM F1921. A bond strength of 2N is the minimum bond strength value for evaluating hot sealing, and if the bond strength is 2N or higher, hot sealing is considered to have been achieved without any particular problems. A biodegradable resin molded article according to one embodiment of the present invention can achieve hot sealing at a much lower temperature than conventional methods.

[0063] According to another embodiment of the invention, the biodegradable resin molded article may have a seal strength of about 2 N or more, or about 2 N to about 10 N, or about 2.5 N to about 5 N, measured at about 110°C according to ASTM F1921.

[0064] And the biodegradable resin molded article may have a seal strength value of about 3 N or more, or about 3 N to about 10 N, or about 4 N to about 5 N when measured under the conditions of about 114 °C based on ASTM F1921. As described above, the biodegradable resin molded article according to an example of the present invention can achieve a high seal strength value even at a very low temperature compared to the existing ones.

Advantages of the Invention

[0065] The resin composition of the present invention can provide resin products such as hot-seal films and hot-seal bags that are excellent in biodegradability, have excellent mechanical properties, and can achieve high seal strength even at a low temperature during hot sealing.

Embodiments for Carrying Out the Invention

[0066] Hereinafter, the actions and effects of the invention will be described in more detail through specific examples of the invention. However, such examples are merely presented as examples of the invention and do not define the scope of the invention.

Examples

[0067] Information on the samples used As polybutylene adipate-co-terephthalate, a product TH801T of Tunhe was prepared. Melting point: 119 °C, melt index (190 °C 21.6 Kg): 2.7 g / 10 min As polylactic acid, a product (AI-1001) of ESUN was prepared. Density: 1.24 g / cm 3 , melt index (190 °C 21.6 Kg): 3.82 g / 10 min

[0068] As the compatibilizer, the following products were used.

[0069] Example: Maleic anhydride-modified polyolefin elastomer FUSABOND N493 (maleic anhydride-modified ethylene-1-octene copolymer elastomer, hereinafter, 493); Density: 0.87 g / cm 3 ; Melting point: 50 °C; Freezing point: 28 °C; Melt index (190 °C, 21.6 Kg): 1.6 g / 10 min; Maleic graft ratio: 0.5 wt% KT-915 (Maleic anhydride-modified ethylene-propylene-diene elastomer, hereinafter 915 ): Density: 0.86 - 0.88 g / cm 3 ; Melt index (190 °C, 2.16 Kg): 0.5 - 1.5 g / 10 min; Maleic graft ratio: 1.0 wt%

[0070] Comparative Example: Maleic anhydride-modified polypropylene FUSABOND P353 (hereinafter 353 ): Density: 0.904 g / cm 3 ; Melting point: 132 °C; Freezing point: 92 °C; Melt index (190 °C, 21.6 kg): 22.4 g / 10 min; Maleic graft ratio: 1.3 wt%

[0071] Comparative Example: Maleic anhydride-modified polyethylene FUSABOND E100 (hereinafter 100 ): Density: 0.954 g / cm 3 ; Melting point: 134 °C; Freezing point: 115 °C; Melt index (190 °C, 21.6 Kg): 2 g / 10 min; Maleic graft ratio: 0.8 wt% FUSABOND E588 (hereinafter 588 ): Density: 0.93 g / cm 3 ; Melting point: 120 °C; Freezing point: 102 °C; Melt index (190 °C, 2.16 Kg): 1.75 g / 10 min; Maleic graft ratio: 0.8 wt%

[0072] Inorganic additive: Calcium carbonate was used as the inorganic additive. Calcium carbonate: Product of Omya, Hydrocarb 95T

[0073] A resin composition was produced according to the composition shown in Table 1 below. Specifically, the PBAT, PLA, and compatibilizer were introduced into a twin-screw extruder (32 mm) according to the composition shown in the following table, and extrusion was carried out under the conditions of a barrel temperature of 200 °C, a feed rate of 30 kg / hr, and 300 rpm to produce the resin composition in the form of pellets.

[0074] Using a single-screw extruder (Single Screw Extruder, Blown Film M / C, 19π, L / D = 25), the manufactured pellets were formed at an extrusion temperature of about 160 °C to about 170 °C to a thickness of 0.05 mm to produce a blown film. At this time, the blow-up ratio was about 1.8.

Table 1

[0075] Measurement of physical properties Measurement of tensile strength and elongation at break Using a universal testing machine (manufacturer: Instron, model name: Model5965), the tensile strength value of the film was measured based on ISO527.

[0076] The test specimens were manufactured in the shape of a bar with a width x length of (10 mm x 150 mm).

[0077] Measurement of hot seal start temperature and seal strength Using a hot tack tester (manufacturer: Swiss Management, model name: Model4000), based on ASTM F1921, the seal strength value corresponding to the seal temperature was measured, and the temperature value at which it reached 2 N was determined as the hot seal start temperature value.

[0078] The above measurement results were summarized in Table 2 below.

Table 2

[0079] Referring to Table 2 above, it can be clearly confirmed that the resin composition according to an embodiment of the present invention can achieve a very high elongation rate, tensile strength, etc., and at the same time can achieve a high bonding strength even at a low temperature during hot sealing.

[0080] However, as in the reference example, when the content of polylactic acid is excessively high, problems occur such as increased hardness, decreased elongation rate, and decreased bonding strength during hot sealing.

[0081] On the other hand, the experiments were repeated by varying the types of compatibilizers.

[0082] A resin composition was produced according to the composition shown in Table 3 below. Specifically, 80 parts by weight of the above-mentioned PBAT, 20 parts by weight of PLA, 20 parts by weight of an inorganic additive, and a compatibilizer were charged into a twin-screw extruder (32 mm) according to the composition shown in the following table, and extrusion was carried out under the conditions of a barrel temperature of 200°C, a feed rate of 30 kg / hr, and 300 rpm to produce the resin composition in pellet form.

[0083] For the pellets thus produced, a blown film was produced by using a single-screw extruder (Single Screw Extruder, Blown Film M / C, 19π, L / D = 25) and molding to a thickness of about 0.05 mm at an extrusion temperature of about 160°C to about 170°C. At this time, the blow-up ratio was about 1.8.

[0084] The measurement results are summarized in Tables 3 and 4 below.

Table 3

Table 4

[0085] Referring to Table 3 above, in Comparative Example 2-1 where no compatibilizer is used at all, and in other comparative examples using a maleic anhydride-modified polyolefin-based compatibilizer that is not a maleic anhydride-modified polyolefin elastomer, their mechanical properties are inferior to those of the examples. It can also be confirmed that the hot seal start temperature is very high, and the value of the hot seal strength within the same temperature range is very low.

Claims

1. A resin composition comprising 1 to 30 parts by weight of polylactic acid (PLA) and 0.01 to 10 parts by weight of maleic anhydride-modified polyolefin elastomer based on 100 parts by weight of polybutylene adipate terephthalate (PBAT).

2. The resin composition according to claim 1, wherein the maleic anhydride-modified polyolefin elastomer is an ethylene-alpha olefin copolymer grafted with maleic anhydride.

3. The resin composition according to claim 2, wherein the ethylene-alpha olefin copolymer is one or more selected from the group consisting of ethylene-1-butene, ethylene-1-pentene, ethylene-1-hexene, ethylene-1-heptene, and ethylene-1-octene.

4. The resin composition according to any one of claims 1 to 3, wherein the maleic anhydride-modified polyolefin elastomer has a melting point of 40°C to 60°C and a freezing point of 20°C to 35°C as measured based on ASTM D3418.

5. The resin composition according to any one of claims 1 to 4, wherein the maleic anhydride-modified polyolefin elastomer has a melt index value of 1.3 g / 10 min to 2.0 g / 10 min as measured under the conditions of 190°C and 21.6 kg based on ASTM D1238.

6. The resin composition according to any one of claims 1 to 5, wherein the maleic anhydride-modified polyolefin elastomer has a graft ratio of maleic anhydride of more than 0 wt% and less than 1 wt%.

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

8. The biodegradable resin molded article according to claim 7, wherein the biodegradable resin molded article is a biodegradable film.

9. The value of the tensile strength measured based on ISO 527 is 250 to 500 kgf / cm ２ The biodegradable resin molded article according to claim 7 or 8, which is such.

10. The biodegradable resin molded article according to any one of claims 7 to 9, wherein the elongation rate value measured based on ISO 527 is 200 to 600%.

11. The biodegradable resin molded article according to any one of claims 7 to 10, which is a hot-seal film.

12. The biodegradable resin molded article according to any one of claims 7 to 11, wherein the value of the hot seal start temperature measured under the condition of 2 N based on ASTM F1921 is 80°C to 120°C.

13. The biodegradable resin molded article according to any one of claims 7 to 11, wherein the value of the seal strength measured under the condition of 110°C based on ASTM F1921 is 2 N or more.

14. The biodegradable resin molded article according to any one of claims 7 to 11, wherein the value of the seal strength measured under the condition of 114°C based on ASTM F1921 is 3 N or more.

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