Biodegradable polyester composite material as well as preparation method and application thereof

Abstract

The invention relates to a biodegradable polyester composite material as well as a preparation method and application thereof, and belongs to the technical field of compositions of high-molecular compounds. The biodegradable polyester composite material disclosed by the invention is prepared from the following components in parts by weight: 58 to 98 parts of PBAT resin, 5 to 40 parts of mineral powder and 0.1 to 1 part of hydrophobic modifier, the hydrophobic modifier is an amidation reaction product derived from long-chain fatty acid and aminoalkylsilane. The biodegradable polyester composite material has good mechanical properties and high water vapor barrier property.

Description

Technical Field

[0001] This invention relates to the field of polymer composition technology, and more particularly to a biodegradable polyester composite material, its preparation method, and its application. Background Technology

[0002] Mulching technology can significantly improve crop yield and quality by reducing water evaporation, suppressing weed growth, and regulating soil temperature and humidity, especially in arid and cold regions. However, commonly used mulches are mainly made of polyethylene, which is difficult to degrade after use and easily leads to serious "white pollution." Using biodegradable mulches (made of PBAT) can effectively solve this problem. However, in practical applications, it has been found that biodegradable mulches are not as effective at retaining water and moisture as polyethylene mulches. To improve the water and moisture retention performance of biodegradable mulches, existing technologies mainly involve blending PBAT with other resins (such as PPC or PLA resins); however, these biodegradable mulches are prone to microphase separation during use, leading to failure in water vapor barrier function, and consequently, poor water and moisture retention. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a biodegradable polyester composite material, its preparation method, and its application.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a biodegradable polyester composite material, comprising the following components by weight: 58-98 parts of PBAT resin, 5-40 parts of mineral powder, and 0.1-1 parts of hydrophobic modifier. The hydrophobic modifier is derived from the amidation reaction product of long-chain fatty acids and aminoalkylsilanes.

[0005] Water vapor permeates through a membrane in four steps: adsorption, dissolution, diffusion, and desorption. Adsorption and desorption are related to the surface hydrophilicity / hydrophobicity of the membrane, while dissolution and diffusion are related to the membrane material (i.e., the polarity of the polymer and the free volume of the polymer molecular chains). This invention improves the mechanical properties of biodegradable polyester composites by combining specific hydrophobic modifiers with PBAT resin and mineral powder. Some hydrophobic modifiers can be modified on the surface of the mineral powder to promote uniform dispersion of the mineral powder in the PBAT resin. Long-chain fatty acid segments in the hydrophobic modifiers can also be used to enhance hydrophobicity, thereby reducing the adsorption of water molecules at the interface between the PBAT resin and the mineral powder. At the same time, during the blown film process of the biodegradable polyester composite, some hydrophobic modifiers can migrate to the surface of the membrane under hydrophilic-hydrophobic interaction to form a hydrophobic layer, thereby significantly improving the membrane's water vapor barrier performance.

[0006] In the biodegradable polyester composite material of this invention, PBAT resin is the matrix resin with a mass fraction ≥55%; the amidation reaction product of long-chain fatty acids and aminoalkylsilane refers to the compound obtained by reacting the carboxyl group (-COOH) in the long-chain fatty acid with the primary amino group (-NH2) in the aminoalkylsilane.

[0007] In some embodiments, the weight parts of PBAT resin in the biodegradable polyester composite material may be, but are not limited to, any one or any two of the following values: 58 parts, 60 parts, 63 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 77 parts, 80 parts, 83 parts, 85 parts, 87 parts, 90 parts, 93 parts, 95 parts, and 98 parts.

[0008] In some embodiments, the weight parts of mineral powder in the biodegradable polyester composite material may be, but are not limited to, any one or any two of the following: 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, and 40 parts.

[0009] In some embodiments, the weight parts of the hydrophobic modifier in the biodegradable polyester composite material may be, but are not limited to, any one or any two of the following values: 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part.

[0010] In some embodiments, the molar ratio of the carboxyl group in the long-chain fatty acid to the primary amino group of the aminoalkylsilane is 1:0.8 to 1:1.2, preferably 1:1, for example, but not limited to any or both of 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1, 1:1.15, 1:1.2.

[0011] Hydrophobic modifiers can be obtained from commercial sources or by self-production. Self-production methods include, but are not limited to, the following: mixing long-chain fatty acids, aminoalkylsilanes and organic solvents, and reacting them in an inert gas atmosphere at 100°C to 120°C for 3 to 6 hours to obtain hydrophobic modifiers.

[0012] In some embodiments, the organic solvent may be, but is not limited to, at least one of toluene, benzene, dimethyl sulfoxide, dimethylformamide, and xylene.

[0013] As a preferred embodiment of the biodegradable polyester composite material of the present invention, it comprises the following components by weight: 70-85 parts of PBAT resin, 15-30 parts of mineral powder, and 0.3-0.8 parts of hydrophobic modifier.

[0014] As a preferred embodiment of the biodegradable polyester composite material of the present invention, the PBAT resin has a melt mass flow rate of ≤10g / 10min under the conditions of 190°C and 2.16kg (test standard is ISO 1133-2011), preferably 2g / 10min to 6g / 10min, for example, but not limited to any one or any two of the following values: 10g / 10min, 9g / 10min, 8g / 10min, 7g / 10min, 6g / 10min, 5g / 10min, 4g / 10min, 3g / 10min, and 2g / 10min.

[0015] By controlling the melt flow rate of PBAT resin within the above range, the biodegradable polyester composite material can have suitable melt strength, thereby better enhancing the stability of the blown film. At the same time, it is also beneficial to generate stronger shear force in melt blending, so as to promote the uniform dispersion of mineral powder and hydrophobic modifier.

[0016] As a preferred embodiment of the biodegradable polyester composite material of the present invention, the long-chain fatty acid is a long-chain fatty acid having 15-26 carbon atoms, such as at least one of palmitic acid (CAS No. 57-10-3), stearic acid (CAS No. 57-11-4), oleic acid (CAS No. 112-80-1), linoleic acid (CAS No. 60-33-3), and creosotenic acid (CAS No. 557-59-5).

[0017] As a preferred embodiment of the biodegradable polyester composite material of the present invention, the aminoalkyl silane includes at least one of γ-aminopropyltrimethoxysilane (CAS No. 13822-56-5), γ-aminopropyltriethoxysilane (CAS No. 919-30-2), N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (CAS No. 1760-24-3), N-(β-aminoethyl)-γ-aminopropyltriethoxysilane (CAS No. 5089-72-5), and N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (CAS No. 3069-29-2).

[0018] In a preferred embodiment of the biodegradable polyester composite material of the present invention, the mineral powder includes at least one of calcium carbonate and talc.

[0019] In a preferred embodiment of the biodegradable polyester composite material of the present invention, the mineral powder is a mixture of calcium carbonate and talc, wherein the mass ratio of calcium carbonate to talc is 1:0.5 to 1:2, for example, but not limited to any one or any two of the following: 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.

[0020] Studies have found that, compared to single mineral powders (calcium carbonate or talc), combining calcium carbonate and talc in specific quantities can produce a significant synergistic effect. The granular calcium carbonate can act as rigid particles to disperse stress and improve the elastic modulus of the film; the lamellar talc can absorb energy through slippage in the matrix to improve the toughness of the film. Moreover, calcium carbonate is also beneficial in inhibiting the lamellar stacking of talc to improve the blown film performance of biodegradable polyester composites.

[0021] In a preferred embodiment of the biodegradable polyester composite material of the present invention, the calcium carbonate has a particle size D 50 The value can be from 0.75μm to 2.5μm, for example, but is not limited to any or both of the following: 0.75μm, 1μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 2μm, 2.3μm, 2.5μm.

[0022] As a preferred embodiment of the biodegradable polyester composite material of the present invention, the particle size D of the talc powder is... 50 The value can be from 2μm to 5μm, for example, but is not limited to any one or both of 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, and 5μm.

[0023] As a preferred embodiment of the biodegradable polyester composite material of the present invention, the surface of the calcium carbonate is coated with an activator, the activator including at least one of aluminate and stearic acid.

[0024] When calcium carbonate is coated with an activator, the non-polar long chain of the activator can be used to improve the dispersion uniformity of calcium carbonate in the PBAT resin matrix. At the same time, the activator coating layer can also act as a "flexible buffer layer" to uniformly transfer stress, thereby better improving the mechanical properties of biodegradable polyester composites.

[0025] Without affecting the effectiveness of the present invention, the biodegradable polyester composite material of the present invention may also contain one or more additives, including but not limited to at least one of antioxidants, slip agents, and colorants.

[0026] Based on the total mass of the biodegradable polyester composite material, the antioxidant has a mass fraction of 0.01% to 3%, the slip agent has a mass fraction of 0.01% to 3%, and the colorant has a mass fraction of 0.01% to 3%.

[0027] In some embodiments, the antioxidant may be at least one selected from hindered phenolic antioxidants and phosphite (phosphorus) antioxidants.

[0028] For example, hindered phenolic antioxidants include, but are not limited to, at least one of 4,4'-methylene-bis(2,6-di-tert-butylphenol), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetratetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0029] For example, phosphite (phosphorus) antioxidants include, but are not limited to, at least one of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol-diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-diphosphite, distearate-pentaerythritol-diphosphite, [bis(2,4-di-tert-butyl-5-methylphenoxy)phosphino]biphenyl, and N,N-bis[2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxophosphazenecycloheptatrien-6-yl]oxy]-ethyl]ethylamine.

[0030] In some embodiments, the lubricant may be at least one selected from erucamide, oleamide, and stearamide.

[0031] Secondly, the present invention provides a method for preparing the above-mentioned biodegradable polyester composite material, comprising the following steps: mixing the components uniformly and melting and extruding to obtain the biodegradable polyester composite material.

[0032] In some implementations, a twin-screw extruder can be used for melt extrusion, with a melt extrusion temperature of 170°C to 200°C and a screw speed of 200 to 300 rpm.

[0033] Thirdly, the present invention provides an application of the above-mentioned biodegradable polyester composite material in the preparation of biodegradable films or bags.

[0034] The biodegradable film is formed by using the above-mentioned biodegradable polyester composite material through melt blow-blowing; preferably, the blow-blowing ratio used in the melt blow-blowing method is 2 to 4; the biodegradable bag is obtained by heat-sealing with the biodegradable film.

[0035] For example, biodegradable films or bags include, but are not limited to, mulch films, fruit and vegetable bags, bread / pastry bags, meat tray films, food container sealing films, disposable tableware packaging bags, tea / coffee capsule packaging bags, beverage cup sealing films, garbage bags, shopping bags, express delivery bags, document bags, flower packaging, etc.

[0036] Fourthly, the present invention provides a membrane or bag made of the above-mentioned biodegradable polyester composite material.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention improves the mechanical properties of biodegradable polyester composites by combining specific hydrophobic modifiers with PBAT resin and mineral powder. Some of the hydrophobic modifiers can be modified on the surface of the mineral powder to promote uniform dispersion of the mineral powder in the PBAT resin. The long-chain fatty acid segments in the hydrophobic modifiers can also be used to enhance the hydrophobic properties, thereby reducing the adsorption of water molecules at the interface between the PBAT resin and the mineral powder. At the same time, during the blown film process of the biodegradable polyester composites, some of the hydrophobic modifiers can migrate to the surface of the film under the influence of hydrophilic-hydrophobic interactions to form a hydrophobic layer, thereby significantly improving the water vapor barrier performance of the film. Detailed Implementation

[0038] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0040] 1. Raw materials and reagents 1) PBAT resin PBAT-1, melt flow rate of 2 g / 10 min, grade A400 LF NC801, manufacturer: Zhuhai Kingfa Biomaterials Co., Ltd. PBAT-2, melt flow rate of 6 g / 10 min, grade A400 NF NC801, manufacturer: Zhuhai Kingfa Biomaterials Co., Ltd. PBAT-3, melt flow rate of 10 g / 10 min, grade A400 MF NC801, manufacturer: Zhuhai Kingfa Biomaterials Co., Ltd.

[0041] 2) Mineral powder Calcium carbonate 1, particle size D 50The particle size is 1.2μm, the grade is ACC-812, and the manufacturer is Xinrong (Lianzhou) Powder Technology Co., Ltd. Calcium carbonate 2, particle size D 50 It has a particle size of 1.5μm, grade ACC-815, and is manufactured by Xinrong (Lianzhou) Powder Technology Co., Ltd. Talc powder 1, particle size D 50 It has a particle size of 2.5μm, grade HTP Ultra 5L, and is manufactured by Liaoning Aihai Yimi Mining Co., Ltd. Talc powder 2, particle size D 50 It has a particle size of 4.5μm, brand name LAmax E05L, and is manufactured by Liaoning Aihaiyimi Mining Co., Ltd.

[0042] 3) Hydrophobic modifier Hydrophobic modifier 1: It is obtained by reacting palmitic acid (commercially available) and γ-aminopropyltrimethoxysilane (commercially available) at a molar ratio of 1:1 in toluene at 100°C under stirring and reflux for 4 hours in a nitrogen atmosphere, and then evaporating the solvent. Hydrophobic modifier 2: It is obtained by reacting oleic acid (commercially available) and γ-aminopropyltrimethoxysilane (commercially available) at a molar ratio of 1:1 in toluene at 100°C under stirring and reflux for 4 hours in a nitrogen atmosphere, and then evaporating the solvent. Hydrophobic modifier 3: It is obtained by reacting stearic acid (commercially available) and γ-aminopropyltrimethoxysilane (commercially available) at a molar ratio of 1:1 in toluene at 100°C under stirring and reflux for 4 hours in a nitrogen atmosphere, and then evaporating the solvent. Hydrophobic modifier 4: It is obtained by reacting stearic acid (commercially available) and γ-aminopropyltriethoxysilane (commercially available) at a molar ratio of 1:1 in toluene at 100°C under stirring and reflux for 4 hours in a nitrogen atmosphere, and then evaporating the solvent.

[0043] 2. Preparation method of the biodegradable polyester composite material of the present invention According to the formula, the components are mixed evenly and then added to a twin-screw extruder. The mixture is melt-extruded and granulated at 170°C to 200°C to obtain a biodegradable polyester composite material. The screw speed of the twin-screw extruder is 300 rpm.

[0044] Table 1 shows the weight parts of each component in the biodegradable polyester composite materials of Examples 1 to 12. Table 2 shows the weight parts of each component in the biodegradable polyester composite materials of Examples 13 to 16 and Comparative Examples 1 to 4. In Tables 1 and 2, " / " indicates that there are no relevant parameters.

[0045] 3. Performance Testing 1) Tensile strength: Tested according to GB / T 1040.3-2006 standard, type 2 specimen, gauge length 100mm, tensile speed 500mm / min.

[0046] 2) Puncture performance: The biodegradable polyester composite materials in each example and comparative example were blown into films, and then the puncture performance of the films was tested according to GB / T 37841-2019.

[0047] 3) Water vapor permeability: The biodegradable polyester composite materials in each example and comparative example were blown into films with a thickness of about 10 μm. The water vapor barrier properties of the films were then tested according to GB / T 1037-2021. Specifically, the cup-type water vapor barrier instrument was used for testing. The test conditions were a temperature of 38℃±0.5℃ and a relative humidity of 90%±2%.

[0048] Table 3. Performance of biodegradable polyester composite materials in each example and comparative example. According to the data in Table 3, the tensile strength (MD) of the biodegradable polyester composite materials in Examples 1 to 16 is ≥20 MPa and the elongation at break (MD) is ≥215%, while the tensile strength (TD) is ≥16 MPa and the elongation at break (TD) is ≥443%, and the puncture resistance is ≥1.7 N·50 μm. -1 Water vapor permeability ≤466g / (m 2 • 24h), indicating that the biodegradable polyester composite material of the present invention possesses both good mechanical properties and high water vapor barrier properties. Furthermore, according to Examples 1, 1, 2, and 3, it can be found that using long-chain fatty acids or aminoalkylsilanes alone as hydrophobic modifiers, or simply physically mixing long-chain fatty acids and aminoalkylsilanes as hydrophobic modifiers, is insufficient to effectively improve the water vapor barrier properties of the biodegradable polyester composite material.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A biodegradable polyester composite material, characterized in that, By weight, it includes the following components: 58-98 parts PBAT resin, 5-40 parts mineral powder, and 0.1-1 parts hydrophobic modifier; The hydrophobic modifier is derived from the amidation reaction product of long-chain fatty acids and aminoalkylsilanes.

2. The biodegradable polyester composite material as described in claim 1, characterized in that, By weight, it includes the following components: 70-85 parts PBAT resin, 15-30 parts mineral powder, and 0.3-0.8 parts hydrophobic modifier.

3. The biodegradable polyester composite material as described in claim 1, characterized in that, The PBAT resin has a melt flow rate of ≤10g / 10min at 190℃ and 2.16kg.

4. The biodegradable polyester composite material as described in claim 1, characterized in that, The long-chain fatty acids include at least one of palmitic acid, stearic acid, oleic acid, linoleic acid, and lignin. And / or, the aminoalkylsilane includes at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane.

5. The biodegradable polyester composite material as described in claim 1, characterized in that, The mineral powder includes at least one of calcium carbonate and talc.

6. The biodegradable polyester composite material as described in claim 5, characterized in that, The mineral powder is a mixture of calcium carbonate and talc, and the mass ratio of calcium carbonate to talc is 1:0.5 to 1:

2. And / or, the particle size D of the calcium carbonate 50 The range is from 0.75 μm to 2.5 μm; And / or, the particle size D of the talc powder 50 The size ranges from 2μm to 5μm.

7. The biodegradable polyester composite material as described in claim 1, characterized in that, The surface of the mineral powder is coated with an activator, which includes at least one of aluminate and stearic acid.

8. A method for preparing the biodegradable polyester composite material according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing the components evenly and then melting and extruding them to obtain a biodegradable polyester composite material.

9. The use of the biodegradable polyester composite material according to any one of claims 1 to 7 in the preparation of biodegradable films or bags.

10. A film or bag, characterized in that, Made from the biodegradable polyester composite material according to any one of claims 1 to 7.

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