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 resin products such as hot sealing films and hot sealing bags that are excellent in biodegradability and can achieve high sealing strength even at low temperatures 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 products, and agricultural vinyls.

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

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

[0005] The agricultural film is often 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. In addition, the soil temperature can be easily adjusted, beneficial bacteria in the soil can be grown, soil erosion can be prevented, and soil moisture can be maintained.

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

[0007] However, as described above, the polyethylene film, which is widely used as a hot-sealing bag for food packaging or a martingale material, does not decompose in the natural environment and has 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 flows into the bodies of marine organisms, accumulates in the ecosystem, and affects the entire food chain.

[0009] Therefore, research on alternatives to the conventionally used thermoplastic plastics is necessary.

[0010] To solve this problem, recently, the development of martingale 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 a resin product that can achieve high sealing strength even at low temperatures during hot sealing.

[0012] Also, this specification aims to provide a biodegradable resin molded product containing the above resin composition.

Means for Solving the Problems

[0013] This specification provides a resin composition containing 0.5 to 60 parts by weight of polylactic acid and 0.1 to 15 parts by weight of epoxidized cardanol with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0014] The resin composition can contain about 1 to about 45 parts by weight of the polylactic acid with respect to 100 parts by weight of the polybutylene adipate terephthalate (PBAT).

[0015] The resin composition may have a weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid of about 6.5:3.5 or more.

[0016] The resin composition may have a weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid of about 9.5:0.5 or less.

[0017] The resin composition can contain 0.2 to 10 parts by weight of the epoxidized cardanol with respect to 100 parts by weight of the polybutylene adipate terephthalate (PBAT).

[0024] The epoxidized cardanol can contain a compound represented by the following Chemical Formula 2.

[0025]

Chemical Formula

[0026] In Chemical Formula 2 above, EA is an epoxidized alkoxy having 2 to 5 carbon atoms, n is an integer of 0 to 10, m is an integer of 0 to 10, and R is hydrogen or a methyl group.

[0027] The resin composition can contain 0.01 to 10 parts by weight of the epoxidized cardanol with respect to a total of 100 parts by weight of the polybutylene adipate terephthalate (PBAT) and the polylactic acid.

[0028] The resin composition can contain about 1 to about 50 parts by weight of an inorganic filler with respect to a total of 100 parts by weight of the polybutylene adipate terephthalate (PBAT) and the polylactic acid.

[0029] Also, this specification provides a biodegradable resin molded article containing the aforementioned resin composition.

[0030] The biodegradable resin molded article has a tensile strength value measured according to the ISO 527 standard of about 250 to about 500 kgf / cm 2 or about 250 kgf / cm 2 to about 400 kgf / cm 2 and may be so.

[0031] According to an embodiment of the invention, the biodegradable resin molded article may have an elongation rate value measured according to the ISO 527 standard of about 300% or more.

[0032] And the biodegradable resin molded article may be a biodegradable film.

[0033] And the biodegradable resin molded article may be a heat-sealing film.

[0034] The biodegradable resin molded article may have a hot-sealing start temperature value measured under 2N conditions according to the ASTM F1921 standard of about 80°C to about 120°C, or about 100°C to about 120°C, or about 105°C to about 116°C, or about 105°C to about 115°C.

[0035] The terms used in this specification are merely used to explain exemplary embodiments and are not intended to limit the present invention.

[0036] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0037] In this specification, terms such as "including", "comprising" or "having" are used to describe implemented features, numbers, steps, components or combinations thereof, and do not preclude one or more other features, numbers, steps, components, combinations thereof or addabilities in advance.

[0038] Also, in this specification, when each layer or element is referred to as being "formed on" or "above" each layer or element, it means that each layer or element is formed directly on each layer or element, or that other layers or elements can be additionally formed between the layers, on the object, or on the substrate.

[0039] While the present invention can be subject to various modifications and can have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed forms, and it must be understood to include all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention.

[0040] Hereinafter, the present invention will be described in detail.

[0041] The inventors of the present invention discovered that when using epoxidized cardanol together with a blending resin obtained by blending polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA), the mechanical properties such as elongation rate and tensile strength are very excellent, and high bonding strength can be achieved even at a low temperature during hot sealing. Based on this discovery, the present invention was completed.

[0042] A resin composition according to one aspect of the present invention contains 0.5 to 60 parts by weight of polylactic acid and 0.1 to 15 parts by weight of epoxidized cardanol with respect to 100 parts by weight of polybutylene adipate terephthalate (PBAT).

[0043] The resin composition can contain about 1 to about 45 parts by weight of the polylactic acid with respect to 100 parts by weight of the polybutylene adipate terephthalate (PBAT), and can contain 1 part by weight or more, or 5 parts by weight or more, or 10 parts by weight or more, or 45 parts by weight or less, or 43 parts by weight or less.

[0044] In the resin composition, the weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid may be about 6.5:3.5 or more, or about 6.9:3.1 or more, or about 7.5:2.5 or more.

[0045] In the resin composition, the weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid may be about 9.5:0.5 or less, or about 9.1:0.9 or less.

[0046] When the amount of polylactic acid contained is excessively small, the effect of improving the mechanical properties of PBAT may not be shown. When the amount of polylactic acid contained is excessively large, problems such as increased hardness and decreased elongation rate of the resin composition may occur. In particular, when the resin composition is processed into a biodegradable film or the like, the processability and the like may decrease, and it may be difficult to realize the physical properties required for applications such as marting film and hot-sealing film.

[0047] 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 that can be biodegraded, and thus has attracted attention as a substitute for polyolefin-based polymers mainly used in packaging materials and agricultural films.

[0048] However, since the mechanical properties of soft PBAT alone are somewhat insufficient for such applications, it is mainly used by blending with hard polylactic acid (PLA); or PBAT is used alone and compounded with an organic filler such as carbon black.

[0049] However, since the compatibility of PBAT and PLA is very low, a compatibilizer must be used during blending.

[0050] Therefore, the resin composition according to one aspect of the present invention contains epoxidized cardanol as a compatibilizer component.

[0051] Due to its molecular structural characteristics, epoxidized cardanol can increase the flexibility of the polymer chain, enhance the compatibility between PBAT and PLA, and when a film is manufactured using such a composition, it can increase the chain diffusion and entanglement between the film interfaces.

[0052] Thereby, the resin composition according to one aspect 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.

[0053] The resin composition can contain about 0.1 to about 15 parts by weight, or about 0.1 part by weight or more, or about 0.2 part by weight or more, or about 0.3 part by weight or more, or about 0.4 part by weight or more, or about 15 parts by weight or less, or about 10 parts by weight or less, or about 5 parts by weight or less, or about 4.5 parts by weight or less of the epoxidized cardanol based on 100 parts by weight of the polybutylene adipate terephthalate (PBAT).

[0062] The epoxidized cardanol can contain a compound represented by the following Chemical Formula 2.

[0063]

Chemical Formula

[0064] In the above Chemical Formula 2, EA is an epoxidized alkoxy having 2 to 5 carbon atoms, n is an integer from 0 to 10, or 1 or more, or 3 or more, or 10 or less, or 8 or less, m is an integer from 0 to 10, or 1 or more, or 3 or more, or 10 or less, or 8 or less, and R is hydrogen or a methyl group.

[0065] The compound represented by Chemical Formula 2 as described above contains two epoxy groups, and includes all alkyl groups and benzene rings in the molecule, which can appropriately increase the flexibility and rigidity of the polymer chain, and can enhance the compatibility between PBAT and PLA.

[0066] The resin composition can contain about 0.01 parts by weight to about 10 parts by weight, or about 0.1 parts by weight to about 5 parts by weight, or about 0.1 to about 1 part by weight of the epoxidized cardanol based on a total of 100 parts by weight of the polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0067] When the content of epoxidized cardanol is excessively low compared to polybutylene adipate terephthalate (PBAT) and polylactic acid, the compatibility between PBAT and PLA may decrease, and there may be a problem that blending between polybutylene adipate terephthalate (PBAT) and polylactic acid is not well performed. When the content is excessively high, there may be a problem that the mechanical properties decrease instead.

[0068] And the resin composition can contain about 0.01 parts by weight to about 10 parts by weight, or about 0.1 parts by weight to 5 parts by weight of the compound represented as the epoxidized cardanol based on 100 parts by weight of the polybutylene adipate terephthalate (PBAT).

[0069] When the content of epoxidized cardanol is excessively low compared to polybutylene adipate terephthalate (PBAT), the compatibility between PBAT and PLA may decrease, and there may be a problem that blending is not performed. When the content of epoxidized cardanol is excessively high compared to polybutylene adipate terephthalate (PBAT), the average length of the PBAT main chain is likely to become excessively long, which may deteriorate the processability of the resin composition and make it difficult to perform blown film forming, and there may be a problem that the mechanical properties of the resin composition such as the elongation rate decrease.

[0070] When epoxidized cardanol is included within the above range as compared with polybutylene adipate terephthalate (PBAT), the compatibility of PBAT and PLA will increase together with an appropriate molecular weight increasing effect, resulting in excellent processability and mechanical properties. In particular, even when inorganic additives or the like are added, properties such as excellent processability and a high elongation rate value can be maintained.

[0071] In addition, the resin composition according to an embodiment of the invention may further contain other additives. The additives can be used without particular limitation as general additives used during the molding of resin compositions in the technical field to which the present invention pertains, that is, the field of thermoplastic polymers.

[0072] The additives can include heat stabilizers, UV stabilizers, and the like.

[0073] And the additives may be included in an amount of about 1 to about 30 parts by weight based on a total of 100 parts by weight of the polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0074] And the resin composition can include about 1 to about 50 parts by weight, or about 10 to about 30 parts by weight, or about 15 to about 25 parts by weight of an inorganic filler based on a total of 100 parts by weight of the polybutylene adipate terephthalate (PBAT) and polylactic acid.

[0075] The inorganic filler can improve the mechanical properties and processability of the resin composition. When the inorganic filler is contained in an excessively small amount, there may be a problem that the above-mentioned advantageous effects are not shown. When the inorganic filler is contained in an excessively large amount, there may be a problem that the mechanical properties and processability of the resin composition rather decrease.

[0076] In addition, this specification provides a biodegradable resin molded article containing any one or more of the resin compositions described throughout the above-mentioned specification.

[0077] The biodegradable resin molded article may be a biodegradable film, specifically, it may be a biodegradable blown film formed by a blowing process.

[0078] The biodegradable resin molded article has a tensile strength value measured according to the ISO 527 standard of about 250 kg / cm 2 ~ about 500 kg / cm 2 or about 250 kg / cm 2 ~ about 400 kg / cm 2 and can have a very excellent tensile strength value.

[0079] And the biodegradable resin molded article may have an elongation rate value measured according to the ISO 527 standard of about 300% or more, or about 350% or more.

[0080] Due to such excellent mechanical properties, it can be used for applications such as agricultural mulching films and packaging materials.

[0081] And according to another example, the biodegradable resin molded article may be a heat-sealing film, more specifically, a heat-sealing film formed by a blowing process.

[0082] According to an embodiment of the invention, the biodegradable resin molded article may have a heat-sealing start temperature value measured under 2N conditions according to the ASTM F1921 standard of about 80°C to about 120°C, or about 100°C to about 120°C, or about 105°C to about 115°C.

[0083] The joining strength of 2N is the minimum joining strength value for evaluating heat sealing. When the joining strength is 2N or more, it can be considered that heat sealing has been achieved without special problems. The biodegradable resin molded article according to an example of the present invention can achieve heat sealing even at a very low temperature compared to the prior art.

[0084] According to an embodiment of the invention, the biodegradable resin molded article may have a sealing strength value measured under the condition of about 112 °C according to ASTM F1921 standard of about 2 N or more, or may be about 2 N to about 4 N.

[0085] According to another embodiment of the invention, the biodegradable resin molded article may have a sealing strength value measured under the condition of about 114 °C according to ASTM F1921 standard of about 2 N or more, or may be about 2 N to about 4 N.

[0086] As described above, the biodegradable resin molded article according to an example of the present invention can achieve a high sealing strength value even at a very low temperature compared with the prior art.

Effect of the Invention

[0087] The resin composition of the present invention can provide resin products such as a hot-sealing film and a hot-sealing bag that are excellent in biodegradability, have excellent mechanical properties, and can achieve a high sealing strength even at a low temperature during hot-sealing.

Modes for Carrying Out the Invention

[0088] 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 illustrations of the invention and do not determine the scope of the invention.

Examples

[0089] <Example> [Information on Samples Used] As polybutylene adipate-co-terephthalate, a product of TH801T from Tunhe was prepared. Melting point: 119 °C, melt index (190 °C 2.16 Kg): 2.7 g / 10 min

[0090] As polylactic acid, a product of ESUN (AI-1001) was prepared. Density: 1.24 g / cm3, Melt Index (190°C, 2.16 Kg): 3.82 g / 10 min

[0091] As the epoxidized cardanol, NC- of Cardolite was used. 514 S was used.

[0092] As the epoxidized soybean oil, SONGSTABE-700 of Matsubara Sangyo was used.

[0093] Inorganic additive: As the inorganic additive, calcium carbonate was used. Calcium carbonate: Product of Omya, Hydrocarb95T

[0094] [Manufacture of resin composition (pellets)] A resin composition was manufactured according to the composition in Table 1 below. Specifically, the PBAT, PLA, and epoxidized cardanol compound were introduced into a twin-screw extruder (32 mm) according to the composition in the table below, and extrusion was carried out under the conditions of a barrel temperature of 200°C, a feed of 30 kg / hr, and 300 rpm to manufacture the resin composition in pellet form.

[0095]

Table 1

[0096] In Table 1 above, as the compatibilizer component, epoxidized soybean oil was used in the case of the comparative example, and epoxidized cardanol was used in the case of the example.

[0097] [Manufacture of blown film ] Using a single-screw extruder (Single Screw Extruder, Blown Film M / C, 19 pie, L / D = 25) for the pellets manufactured above, they were molded to a thickness of 0.05 mm at an extrusion temperature of about 160°C to about 170°C to manufacture a blown film. The blow-up ratio was about 1.8, and the line speed was about 5 m / min.

[0098] [Physical property measurement] (Measurement of tensile strength, elastic modulus, and elongation) Using a universal testing machine (manufacturer: GALDABINI, model name: QUASUR50), the tensile strength value of the film was measured according to the ISO527 standard. The test specimens were manufactured in a bar form with a width × length of (10 mm × 150 mm).

[0099] (Measurement and evaluation of hot sealing start temperature and sealing strength) For the blown film manufactured above, using a hot tack tester (manufacturer: Swiss Management, model name: Model 4000), according to the ASTM F1921 standard, the sealing strength value depending on the sealing temperature was measured, and the temperature value at which it becomes 2 N was determined as the hot sealing start temperature value. Then, based on a sealing temperature of 115°C, when the sealing strength value satisfies 2 N or more, it was marked as good, and when it does not satisfy, it was marked as poor.

[0100] The results of the above measurements were organized in Table 2 below.

[0101]

Table 2

[0102] Referring to Table 2 above, it can be clearly confirmed that the resin composition according to an embodiment of the present invention has physical property values such as tensile strength and elongation that are generally superior to those of the comparative example, and in relation to the sealing characteristics, hot sealing is possible even at a low temperature.

[0103] In the case of the comparative example, it was confirmed that the mechanical properties were generally inferior to those of the example, and in relation to the sealing strength characteristics, the hot sealing start temperature was relatively high, and more energy was required for sealing.

[0104] [Manufacture of resin composition (pellets)] In order to confirm the differences due to the PBAT and PLA composition ratios, resin compositions were produced according to the compositions in Table 3 below. Specifically, the PBAT, PLA, and epoxidized cardanol compound were introduced into a twin-screw extruder (32 mm) according to the compositions in the following table, and extrusion was carried out under the conditions of a barrel temperature of 200 °C, a feed of 30 kg / hr, and 300 rpm to produce the resin composition in pellet form.

[0105] [Table 3]

[0106] [Physical Property Measurement] (Tensile Strength, Elastic Modulus, and Elongation at Break Measurement) Using a universal testing machine (manufacturer: GALDABINI, model name: QUASUR50), the tensile strength value of the film was measured according to the ISO 527 standard. The test specimens were manufactured in the form of bars, with a width × length of (10 mm × 150 mm).

[0107] [Blown Film Manufacturing] Using a single-screw extruder (Single Screw Extruder, Blown Film M / C, 19 die, L / D = 25) for the pellets manufactured above, they were molded to a thickness of 0.05 mm at an extrusion temperature of about 160 °C to about 170 °C to produce a blown film. When manufacturing the blown film, in order to evaluate the processability, the strand was fixed at about 10 m / min, and the maximum expansion ratio was evaluated with the strand.

[0108] (Sealing Strength Measurement and Evaluation) For the blown film manufactured above, using a hot tack tester (manufacturer: Swiss Management, model name: Model 4000), according to the ASTM F1921 standard, with a sealing temperature of 115 °C as the reference, when the sealing strength value satisfies 2 N or more, it was marked as good, and when it does not satisfy, it was marked as bad.

[0109] (Appearance Characteristic Evaluation) The blow films produced in the examples and comparative examples were visually observed. When defects such as convex-concave bending or sagging occurred in the film, it was evaluated as defective; when no special defects were observed, it was evaluated as good.

[0110] The measurement results were tabulated in Table 4 below.

[0111] [Table 4]

[0112] Referring to the above table, 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 relatively low temperature during hot sealing.

Claims

1. Based on 100 parts by weight of polybutylene adipate terephthalate (PBAT), 0.5 to 60 parts by weight of polylactic acid, and 0.1 to 15 parts by weight of epoxidized cardanol are included, The resin composition, wherein the epoxidized cardanol includes a compound represented by the following Chemical Formula 2. 【Chemical Formula 9】 In the above Chemical Formula 2, EA is an epoxidized alkoxy having 2 to 5 carbon atoms, n is an integer from 0 to 10, m is an integer from 0 to 10, and R is hydrogen or a methyl group.

2. Based on 100 parts by weight of the polybutylene adipate terephthalate (PBAT), The resin composition according to Claim 1, including 1 to 45 parts by weight of the polylactic acid.

3. The resin composition according to Claim 1, wherein the weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid is 6.5:3.5 or more.

4. The resin composition according to Claim 1, wherein the weight ratio of polybutylene adipate terephthalate (PBAT) to polylactic acid is 9.5:0.5 or less.

5. Based on 100 parts by weight of the polybutylene adipate terephthalate (PBAT), The resin composition according to Claim 1, including 0.2 to 10 parts by weight of the epoxidized cardanol.

6. Based on 100 parts by weight in total of the polybutylene adipate terephthalate (PBAT) and polylactic acid, the resin composition according to Claim 1, including 0.01 to 10 parts by weight of the epoxidized cardanol.

7. Based on 100 parts by weight in total of the polybutylene adipate terephthalate (PBAT) and polylactic acid, the resin composition according to Claim 1, including 1 to 50 parts by weight of an inorganic filler.

8. A biodegradable resin molded article including the resin composition according to any one of Claims 1 to 7.

9. The tensile strength value measured according to the ISO 527 standard is 250 to 500 kgf / cm 2 The biodegradable resin molded product according to claim 8, which is such.

10. The biodegradable resin molded article according to Claim 8, wherein the elongation rate value measured according to ISO 527 standard is 300% or more.

11. The biodegradable resin molded article according to Claim 8, wherein the hot sealing start temperature value measured under 2N condition according to ASTM F1921 standard is 80°C to 120°C.

12. The biodegradable resin molded article according to Claim 8, which is a biodegradable film.

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