Talcum powder master batch for biodegradable straw, preparation method and application thereof

Abstract

The application provides a talcum powder master batch for biodegradable straws and a preparation method and application thereof, and belongs to the technical field of degradable materials. The talcum powder master batch provided by the application comprises the following components in parts by weight: 15-30 parts of polylactic acid, 30-50 parts of first modified talcum powder, 30-50 parts of second modified talcum powder, and 1.2-2 parts of an auxiliary agent. The first modified talcum powder comprises first talcum powder, a first amino silane coupling agent and castor oil. The second modified talcum powder comprises second talcum powder, a second amino silane coupling agent and epoxy soybean oil.

Description

Technical Field

[0001] This application relates to the field of degradable materials technology, specifically to a biodegradable talc masterbatch for straws, its preparation method, and its application. Background Technology

[0002] In recent years, the development of biodegradable plastics has been increasing, and their applications have been expanding. They are gradually replacing traditional plastics in areas such as packaging materials, disposable tableware, agricultural mulch films, and daily necessities.

[0003] Talc is often used in biodegradable straws to improve their rigidity and heat resistance. The preparation methods of biodegradable straws mainly include: mixing talc and bio-based polyester, then melting and granulating the mixture using a twin-screw extruder to obtain a bio-based polyester composite material, and then extruding the bio-based polyester composite material into a tube preform and forming it into a tube using a single-screw extruder to obtain a biodegradable straw; however, the above methods have the following problems: (1) Bio-based polyester is easily degraded under the strong shear force field during the modification process of the twin-screw extruder, resulting in a decrease in melt strength (an increase in melt index), which is not conducive to the melt forming of bio-based polyester composite material into tubes; (2) Talc is too fluffy and slippery, and the higher the fineness of talc, the lower its powder bulk density, which makes it easier to have unstable feeding and The problem of feeding difficulties; that is, high-quality ultrafine talc powder is extremely difficult to modify and apply to the preparation of biodegradable straws by twin-screw extruders; (3) Although talc-modified biodegradable straws can improve the rigidity and heat resistance of biodegradable straws, due to the strong shear force of twin-screw extruders on bio-based polyester, biodegradable straws are prone to brittleness and breakage, and cannot meet the requirements for application in some high-performance straws or bendable straws; (4) Due to the simple screw structure of single-screw extruders and weak dispersion ability, talc powder cannot be directly mixed into bio-based polyester by powder method and melt extruded into tubes by single-screw extruders, otherwise the talc powder will be unevenly dispersed. For this reason, the talc powder masterbatch produced by traditional methods, due to its generally poor intrinsic dispersion effect, cannot be added to bio-based polyester by simple physical mixing and melt extruded into tubes by single-screw extruders, otherwise the talc powder will be poorly dispersed in bio-based polyester, resulting in a decrease in the overall performance of biodegradable straws and failure to meet appearance requirements. Summary of the Invention

[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a talc masterbatch for biodegradable straws, its preparation method, and its application.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: Firstly, a talc masterbatch is provided, comprising the following components in parts by weight: Polylactic acid 15-30 parts, first modified talc 30-50 parts, second modified talc 30-50 parts, additives 1.2-2 parts; The first modified talc powder comprises first talc powder, first aminosilane coupling agent, and castor oil; The second modified talc powder includes a second talc powder, a second aminosilane coupling agent, and epoxidized soybean oil; The particle size D90 of both the first talc powder and the second talc powder is ≤10μm; The silica content in the first talc powder and the second talc powder is ≥60%.

[0006] In some embodiments, the particle size D90 of the first talc powder and the second talc powder is independently 2-10 μm.

[0007] In some embodiments, based on 100 parts by weight of the first talc powder, the first aminosilane coupling agent is 0.3-1.3 parts by weight, and the castor oil is 0.3-1.3 parts by weight.

[0008] In some embodiments, the second aminosilane coupling agent is 0.3-1.3 parts by weight and the epoxidized soybean oil is 0.3-1.3 parts by weight, with 100 parts by weight of the second talc powder.

[0009] In some embodiments, the first modified talc powder and the second modified talc powder further include a dispersant, wherein the dispersant comprises 0.5-1 parts by weight of 100 parts by weight of the first talc powder and 0.5-1 parts by weight of the second talc powder.

[0010] In some embodiments, the whiteness of the first talc powder and the second talc powder is ≥90.

[0011] In some embodiments, the adjuvant includes at least one of antioxidants and chain extenders.

[0012] In some embodiments, the first aminosilane coupling agent and the second aminosilane coupling agent are each independently selected from at least one of γ-aminopropyltriethoxysilane (KH550), 3-aminopropyltrimethoxysilane (KH540), and N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792).

[0013] Secondly, a method for preparing talc masterbatch is provided, comprising the following steps: After the components are mixed evenly in proportion, they are kneaded in an internal mixer to obtain a premix. The premixed material is added to a single-screw extruder and melt-extruded to granulate, thus obtaining talc masterbatch.

[0014] Thirdly, a bio-based polyester composite material is provided, comprising the following components in parts by weight: 70-98 parts of bio-based polyester and 2-30 parts of the talc masterbatch.

[0015] Fourthly, a biodegradable straw is provided, comprising the aforementioned bio-based polyester composite material.

[0016] Compared with the prior art, the beneficial effects of this application are as follows: This application adds a first modified talc powder and a second modified talc powder to the talc powder masterbatch, and the two are synergistically dispersed to form a talc powder system co-modified by aminosilane coupling agent, castor oil and epoxidized soybean oil, which improves the dispersibility and interfacial compatibility of talc powder in talc powder masterbatch, and prepares bio-based polyester composite material by combining talc powder masterbatch and bio-based polyester. The talc powder masterbatch and bio-based polyester can form a stable interfacial structure; improve the toughness and impact strength of bio-based polyester composite material. Detailed Implementation

[0017] To facilitate understanding of this application, a more complete description will be provided below. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0018] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0019] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0020] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0021] A first aspect of this application provides a talc masterbatch comprising the following components in parts by weight: Polylactic acid 15-30 parts, first modified talc 30-50 parts, second modified talc 30-50 parts, additives 1.2-2 parts; The first modified talc powder comprises first talc powder, first aminosilane coupling agent, and castor oil; The second modified talc powder includes a second talc powder, a second aminosilane coupling agent, and epoxidized soybean oil.

[0022] This application utilizes polylactic acid (PLA) as a carrier in talc masterbatch. PLA has high rigidity and good melt resistance to yellowing. When mixed with a high proportion of modified talc, it maintains excellent resistance to yellowing during the mixing process, preserving the original whiteness and color of the talc. The addition of first and second modified talc powders allows for synergistic dispersion, forming a talc system co-modified with aminosilane coupling agent, castor oil, and epoxidized soybean oil. This improves the dispersibility and interfacial compatibility of talc in the talc masterbatch. The talc masterbatch and polyester are then combined to prepare a bio-based polyester composite material, forming a stable interfacial structure. This improves the toughness and impact strength of the bio-based polyester composite material, as well as the bending resistance and moldability of the biodegradable straw.

[0023] Because aminosilane coupling agent, castor oil, and epoxidized soybean oil have significantly different reactivity and different reaction mechanisms, if aminosilane coupling agent, castor oil, and epoxidized soybean oil are used to modify talc powder simultaneously, incomplete modification reactions will occur. Preparing first modified talc powder and second modified talc powder separately can avoid the problem of incomplete modification reactions.

[0024] In the preparation of the first modified talc powder, the first talc powder and the first aminosilane coupling agent need to be pretreated before adding castor oil for grafting reaction. During the mixing of the first talc powder and the first aminosilane coupling agent, the silanol groups on the surface of the first aminosilane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the first talc powder, or combine with the silyl ether hydroxyl groups on the surface of the first talc powder. This not only removes moisture from the surface of the first talc powder, but also forms silyl ether bonds with the oxygen atoms in the talc powder, significantly improving the compatibility of the first talc powder with polylactic acid. The first dispersant can accelerate the wetting of the first aminosilane coupling agent and the first talc powder, improving the dispersion efficiency. The first aminosilane coupling agent undergoes a condensation reaction with the hydroxyl groups in the castor oil molecular chain, introducing the triglyceride structure and long alkyl chain of the castor oil itself. Using the first aminosilane coupling agent as a bridge, the surface of the first talc powder particles is coated with an organic long-chain layer, which improves the interfacial bonding force and flexibility between the first talc powder and polylactic acid, significantly improving the dispersibility and compatibility of talc powder in bio-based polyester composites, thereby improving the rigidity-toughness balance, mechanical properties, bending resistance and formability of bio-based polyester composites.

[0025] Taking γ-aminopropyltriethoxysilane (KH550) as the first aminosilane coupling agent as an example, the reaction mechanism of the first modified talc is as follows: (1) The ethoxy group (-OCH2CH3) of KH550 hydrolyzes under heating conditions to generate silanol (-Si-OH), and the reaction equation is as follows: NH2(CH2)3Si(OCH2CH2)2+3H2O→NH2(CH2)3Si(OH)2+3CH3CH2OH; (2) The hydrolyzed silanol (-Si-OH) then undergoes a condensation reaction with the hydroxyl groups (-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds, and loses water molecules. The reaction equation is as follows: NH2(CH2)3Si(OH) + HO- [talc surface] → NH2(CH2)3Si-O- [talc surface] + H2O; (3) Silanol (-Si-OH) undergoes a condensation reaction with the hydroxyl group (-OH) of castor oil to form Si-O-Si and remove water molecules.

[0026] In the preparation of the second modified talc, the second talc and the second aminosilane coupling agent need to be pretreated before epoxidized soybean oil is added for grafting. During the mixing of the second talc and the second aminosilane coupling agent, the silanol groups on the surface of the second aminosilane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the second talc, or combine with the silyl ether hydroxyl groups on the surface of the second talc. This not only removes moisture from the surface of the second talc but also forms silyl ether bonds with the oxygen atoms in the talc, significantly improving the compatibility between the first talc and polylactic acid. The second dispersant can accelerate the wetting of the second aminosilane coupling agent and the second talc, improving the dispersion efficiency. The amino group (-NH2) of the second aminosilane coupling agent and the epoxy group of epoxidized soybean oil undergo a direct ring-opening reaction. Using the second aminosilane coupling agent as a bridge, the organic structure of epoxidized soybean oil is grafted onto the surface of the second talc powder through covalent bonding, which improves the toughening, plasticizing and compatibilizing effects of talc masterbatch, significantly improves the dispersibility and compatibility of talc powder in bio-based polyester composites, and thus improves the impact strength of bio-based polyester composites.

[0027] Taking γ-aminopropyltriethoxysilane (KH550) as the first aminosilane coupling agent as an example, the reaction mechanism of the first modified talc is as follows: (1) The ethoxy group (-OCH2CH3) of KH550 hydrolyzes under heating conditions to generate silanol (-Si-OH), and the reaction equation is as follows: NH2(CH2)3Si(OCH2CH2)2+3H2O→NH2(CH2)3Si(OH)2+3CH3CH2OH; (2) The hydrolyzed silanol (-Si-OH) then undergoes a condensation reaction with the hydroxyl groups (-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds, and loses water molecules. The reaction equation is as follows: NH2(CH2)3Si(OH) + HO- [talc surface] → NH2(CH2)3Si-O- [talc surface] + H2O; (3) Epoxidized soybean oil -(CH2-O-CH2) + H2N-(CH2)3-Si(OC2H5)3→Epoxidized soybean oil -CH2-CH(OH)-CH2-NH-(CH2)3-Si(OC2H5)3.

[0028] During the mixing process in the internal mixer, the first modified talc powder and the second modified talc powder prepared separately can be quickly impregnated and dispersed with the polylactic acid carrier. In addition, the first modified talc powder and the second modified talc powder have achieved a preheating effect after being stirred by the high-speed mixer, which reduces the dependence on heating the bottom of the internal mixer and accelerates the plasticization and impregnation with polylactic acid in the internal mixer.

[0029] Specifically, the weight parts of polylactic acid can be a range of 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, and 30 parts, or any combination of both.

[0030] Specifically, the weight parts of the first modified talc powder can be one or any combination of 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, and 50 parts.

[0031] Specifically, the weight parts of the second modified talc can be one or any combination of 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, and 50 parts.

[0032] Specifically, the weight parts of the adjuvant can be one or any combination of 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, and 2 parts.

[0033] Specifically, the particle size D90 of the first talc powder and the second talc powder can each independently be a range of one or any two of 1.5μm, 2μm, 2.5μm, 3μm, 4.5μm, 5μm, 6μm, 8μm, and 10μm; preferably 2-10μm; more preferably 2.5-6μm.

[0034] The particle size D90 of the first talc powder and / or the second talc powder being within the above range is beneficial to improving the mechanical properties of the talc masterbatch-modified bio-based polyester composite material, as well as the bending resistance and formability of the biodegradable straw.

[0035] In this application, D90 refers to the diameter corresponding to the cumulative diameter distribution percentage of the first talc powder or the second talc powder reaching 90%; the particle size of the first talc powder and the second talc powder can be determined by laser particle size analyzer (Mastersizer3000) according to standard GB / T 19077-2024.

[0036] In some embodiments, the silica content in the first talc powder and the second talc powder is ≥60%; for example, it can be a range of one or any two of 60%, 60.5%, 61%, 61.5%, 62%; preferably 62%.

[0037] The silica content in the first and second talc powders is within the above-mentioned range, which is beneficial to improving the mechanical properties of bio-based polyester composite materials containing talc masterbatch, as well as the bending resistance and formability of biodegradable straws.

[0038] In some embodiments, based on 100 parts by weight of the first talc powder, the first aminosilane coupling agent is 0.3-1.3 parts by weight, and the castor oil is 0.3-1.3 parts by weight.

[0039] In this application, the weight parts of the first aminosilane coupling agent and castor oil are within the above-mentioned range, which can improve the dispersibility of talc in bio-based polyester composite materials and improve the mechanical properties, bending resistance and formability of bio-based polyester composite materials containing talc masterbatch.

[0040] Specifically, based on 100 parts by weight of the first talc powder, the weight of the first aminosilane coupling agent can be one or any combination of 0.3 parts, 0.4 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 part, 1.2 parts, 1.3 parts, 1.4 parts, and 1.5 parts; preferably 0.5 to 1.1 parts.

[0041] Specifically, based on 100 parts by weight of the first talc powder, the weight of castor oil can be one or any combination of 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 part, 1.2 parts, 1.3 parts, 1.4 parts, and 1.5 parts; preferably 0.5 to 1.1 parts.

[0042] In some embodiments, the second aminosilane coupling agent is 0.3-1.3 parts by weight and the epoxidized soybean oil is 0.3-1.3 parts by weight, with 100 parts by weight of the second talc powder.

[0043] In this application, the weight parts of the first aminosilane coupling agent and castor oil are within the above-mentioned range, which can improve the dispersibility of talc in bio-based polyester composite materials and improve the mechanical properties, bending resistance and formability of bio-based polyester composite materials containing talc masterbatch.

[0044] Specifically, based on 100 parts by weight of the second talc powder, the weight of the second aminosilane coupling agent can be one or any combination of 0.3 parts, 0.4 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 part, 1.2 parts, 1.3 parts, 1.4 parts, and 1.5 parts; preferably 0.5 to 1.1 parts.

[0045] Specifically, based on 100 parts by weight of the second talc powder, the weight of castor oil can be one or any combination of 0.3 parts, 0.4 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, 1 part, 1.2 parts, 1.3 parts, 1.4 parts, and 1.5 parts; preferably 0.5 to 1.1 parts.

[0046] In some embodiments, the first modified talc powder further includes a first dispersant, wherein the first dispersant is 0.5-1 parts by weight of 100 parts by weight of the first talc powder.

[0047] Adding a first dispersant to the first modified talc powder can improve the dispersibility of the first aminosilane coupling agent and the first talc powder, which is beneficial to the subsequent modification of castor oil.

[0048] Specifically, based on 100 parts by weight of the first talc powder, the weight of the first dispersant can be one or any combination of 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, and 1 part.

[0049] In some embodiments, the second modified talc powder further includes a second dispersant, wherein the second dispersant is 0.5-1 parts by weight of 100 parts by weight of the second talc powder.

[0050] Specifically, based on 100 parts by weight of the second talc powder, the weight of the second dispersant can be one or any combination of 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, and 1 part.

[0051] Adding a second dispersant to the second modified talc can improve the dispersibility of the second aminosilane coupling agent and the second talc, which is beneficial for the subsequent modification of epoxidized soybean oil.

[0052] In some embodiments, both the first dispersant and the second dispersant are ethanol.

[0053] In some embodiments, the whiteness of the first talc powder and the second talc powder is ≥90; for example, it can be a range of values ​​consisting of one or any two of 90, 90.5, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95, 95.5, and 96.

[0054] The whiteness of the first and second talc powders is within the above-mentioned range, which ensures that the biodegradable straws meet the whiteness requirements.

[0055] In some embodiments, the first aminosilane coupling agent and the second aminosilane coupling agent are each independently selected from at least one of γ-aminopropyltriethoxysilane (KH550), 3-aminopropyltrimethoxysilane (KH540), and N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792).

[0056] In some embodiments, the castor oil contains ≥85% ricinoleic acid by mass.

[0057] In some embodiments, the epoxy value of the epoxidized soybean oil is ≥6%.

[0058] In some embodiments, the preparation method of the first modified talc powder includes the following steps: First talc powder, first aminosilane coupling agent and first dispersant (if any) are added to a high-speed mixer. After the first reaction is carried out under heating conditions, castor oil is added to carry out the second reaction to obtain first modified talc powder.

[0059] During the high-speed mixing of the first talc powder and the first aminosilane coupling agent, the silanol groups on the surface of the first aminosilane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the first talc powder, or combine with the silyl ether hydroxyl groups on the surface of the first talc powder. This not only removes moisture from the surface of the first talc powder, but also forms silyl ether bonds with the oxygen atoms in the talc powder, significantly improving the compatibility between the first talc powder and polylactic acid. The first dispersant can accelerate the wetting of the first aminosilane coupling agent and the first talc powder, improving the dispersion efficiency. The first aminosilane coupling agent undergoes a condensation reaction with the hydroxyl groups in the castor oil molecular chain, introducing the triglyceride structure and long alkyl chains of the castor oil itself. Using the first aminosilane coupling agent as a bridge, the surface of the first talc powder particles is coated with an organic long-chain layer, improving the interfacial bonding force and flexibility between the first talc powder and polylactic acid. This significantly improves the dispersibility and compatibility of talc powder in bio-based polyester composites, thereby improving the rigidity-toughness balance, mechanical properties, bending resistance, and moldability of the bio-based polyester composites.

[0060] Taking γ-aminopropyltriethoxysilane (KH550) as the first aminosilane coupling agent as an example, the reaction mechanism of the first modified talc is as follows: (1) The ethoxy group (-OCH2CH3) of KH550 hydrolyzes under heating conditions to generate silanol (-Si-OH), and the reaction equation is as follows: NH2(CH2)3Si(OCH2CH2)2+3H2O→NH2(CH2)3Si(OH)2+3CH3CH2OH; (2) The hydrolyzed silanol (-Si-OH) then undergoes a condensation reaction with the hydroxyl groups (-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds, and loses water molecules. The reaction equation is as follows: NH2(CH2)3Si(OH) + HO- [talc surface] → NH2(CH2)3Si-O- [talc surface] + H2O; (3) Silanol (-Si-OH) undergoes a condensation reaction with the hydroxyl group (-OH) of castor oil to form Si-O-Si and remove water molecules.

[0061] Specifically, the heating temperature is 100-140℃, for example, it can be a range of one or any two of 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, and 140℃.

[0062] Specifically, the mixing speed of the high-speed mixer is 800-1000 r / min, and the mixing time is 3-7 min.

[0063] In order to improve the reaction rate between castor oil and first talc powder, the castor oil was preheated at a temperature of 70-90°C.

[0064] In some embodiments, the method for preparing the second modified talc powder includes the following steps: The second talc powder, the second aminosilane coupling agent, and the second dispersant (if any) are added to a high-speed mixer. After the first reaction is carried out under heating conditions, epoxidized soybean oil is added to carry out the second reaction to obtain the second modified talc powder.

[0065] During the mixing process of the second talc powder and the second aminosilane coupling agent, the silanol groups on the surface of the second aminosilane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the second talc powder, or combine with the silyl ether hydroxyl groups on the surface of the second talc powder. This not only removes moisture from the surface of the second talc powder, but also forms silyl ether bonds with the oxygen atoms in the talc powder, significantly improving the compatibility of the first talc powder with polylactic acid. The second dispersant can accelerate the wetting of the second aminosilane coupling agent and the second talc powder, improving the dispersion efficiency. The amino group (-NH2) of the second aminosilane coupling agent and the epoxy group of epoxidized soybean oil directly undergo a ring-opening reaction. Using the second aminosilane coupling agent as a bridge, the organic structure of epoxidized soybean oil is grafted onto the surface of the second talc powder through covalent bonding, improving the toughening, plasticizing, and compatibilizing effects of the talc masterbatch, significantly improving the dispersibility and compatibility of talc powder in bio-based polyester composites, thereby improving the impact strength of bio-based polyester composites.

[0066] Taking γ-aminopropyltriethoxysilane (KH550) as the first aminosilane coupling agent as an example, the reaction mechanism of the first modified talc is as follows: (1) The ethoxy group (-OCH2CH3) of KH550 hydrolyzes under heating conditions to generate silanol (-Si-OH), and the reaction equation is as follows: NH2(CH2)3Si(OCH2CH2)2+3H2O→NH2(CH2)3Si(OH)2+3CH3CH2OH; (2) The hydrolyzed silanol (-Si-OH) then undergoes a condensation reaction with the hydroxyl groups (-OH) on the surface of talc to form Si-O-Si or Si-O-Mg covalent bonds, and loses water molecules. The reaction equation is as follows: NH2(CH2)3Si(OH) + HO- [talc surface] → NH2(CH2)3Si-O- [talc surface] + H2O; (3) Epoxidized soybean oil -(CH2-O-CH2) + H2N-(CH2)3-Si(OC2H5)3→Epoxidized soybean oil -CH2-CH(OH)-CH2-NH-(CH2)3-Si(OC2H5)3.

[0067] Specifically, the heating temperature is 100-140℃, for example, it can be a range of one or any two of 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, and 140℃.

[0068] Specifically, the mixing speed of the high-speed mixer is 800-1000 r / min, and the mixing time is 3-7 min.

[0069] In order to improve the reaction rate between epoxidized soybean oil and the second talc powder, the epoxidized soybean oil was preheated at a temperature of 70-90℃.

[0070] In some embodiments, the adjuvant includes at least one of antioxidants and chain extenders.

[0071] In some embodiments, the antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants; specific examples of antioxidants include antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 264.

[0072] In some embodiments, the chain extender includes an epoxy-functionalized chain extender; specific examples of epoxy-functionalized chain extenders include ADR-4468 and BTCE-9370.

[0073] In some embodiments, the polylactic acid is selected from at least one of poly-L-lactic acid, polyracemic lactic acid, and lactic acid-glycolic acid copolymer.

[0074] Secondly, the method for preparing the talc masterbatch includes the following steps: After the components are mixed evenly in proportion, they are kneaded in an internal mixer to obtain a premix. The premixed material is added to a single-screw extruder and melt-extruded to granulate, thus obtaining talc masterbatch.

[0075] The set temperatures for the single-screw extruder from the feed port to the die head are as follows: Zone 1 temperature 160-170℃, Zones 2 to 6 temperatures are each 160-175℃, and the screw speed is 30-50 r / min.

[0076] Specifically, the preparation method of the talc masterbatch includes the following steps: First talc powder, first aminosilane coupling agent and first dispersant (if any) are added to a first high-speed mixer, and after a first reaction is carried out under heating conditions, castor oil is added to carry out a second reaction to obtain first modified talc powder; The second talc powder, the second aminosilane coupling agent, and the second dispersant (if any) are added to the second high-speed mixer. After the first reaction is carried out under heating conditions, epoxidized soybean oil is added to carry out the second reaction to obtain the second modified talc powder. Polylactic acid and additives are added to a low-speed mixer in proportion and stirred at a speed of 40~80 r / min for 5~8 min to obtain polylactic acid mixture; Using a mixer preheated to 200℃, after preheating, add the first modified talc powder, the second modified talc powder, and polylactic acid mixture respectively. Start the pressure cover and press down to compact the material. Set the mixing rollers to a speed of 40~50r / min for mixing. During the mixing process, the pressure cover needs to be lifted and pressed down 5~8 times to achieve the compaction, plasticization, and dispersion of the material. When the material temperature rises to 185~190℃, stop the mixing to obtain the premix. The premixed material is added to a single screw extruder for melt extrusion granulation to obtain talc masterbatch. During melt extrusion granulation, the set temperatures of the screw extruder from the feed port to the die head are as follows: Zone 1 temperature 160-170℃, Zones 2 to 6 temperatures are 160-175℃ each, and the screw speed is 30-50 r / min.

[0077] Thirdly, a bio-based polyester composite material is provided, comprising the following components in parts by weight: 70-98 parts of bio-based polyester and 2-30 parts of the talc masterbatch.

[0078] Specifically, the weight parts of the bio-based polyester can be a range of 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts, 96 parts, or 98 parts, or any combination of both.

[0079] Specifically, the weight parts of talc masterbatch can be one or any combination of two of the following: 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, and 30 parts.

[0080] In some embodiments, the bio-based polyester includes at least one of polylactic acid (PLA), bio-based aliphatic, and bio-based aliphatic-aromatic copolyesters.

[0081] In some embodiments, the bio-based fatty acid polyester includes at least one of polylactic acid (PLA), polyhydroxyalkanoate (PHA), polybutylene succinate (PBS), and polybutylene adipate succinate (PBSA).

[0082] In some embodiments, the bio-based aliphatic-aromatic copolyester includes at least one of polybutylene adipate terephthalate (PBAT), polybutylene terephthalate succinate, and polybutylene sebacate terephthalate (PBST).

[0083] In some embodiments, the method for preparing the bio-based polyester composite material includes the following steps: After the talc masterbatch and bio-based polyester are mixed evenly, the resulting mixture is melt-extruded and granulated through a single-screw extruder to obtain a bio-based polyester composite material.

[0084] Fourthly, a biodegradable straw is provided, comprising the aforementioned bio-based polyester composite material.

[0085] Specifically, the method for preparing the biodegradable straw includes the following steps: After the talc masterbatch and bio-based polyester are mixed evenly, the resulting mixture is dried and then fed into a single-screw extruder with a straw preform die to extrude the straw preform. The preform is then passed through a water-cooling, air-cooling, dehydration, and cutting device under the traction equipment to obtain a biodegradable straw.

[0086] This application describes the preparation of biodegradable straws from talc masterbatch and bio-based polyester using a single-screw extruder with a straw preform die. Based on co-modification with silane coupling agent, castor oil, and epoxidized soybean oil, the talc masterbatch exhibits activity and good dispersibility, demonstrating excellent compatibility and dispersibility with the PLA carrier. During the melt extrusion process of the talc masterbatch and bio-based polyester in the single-screw extruder, the talc masterbatch is easily dispersed by the PLA carrier and bio-based polyester, allowing it to be carried along with the PLA carrier flow. The PLA carrier and bio-based polyester can rapidly diffuse into each other, resulting in uniform dispersion of the talc masterbatch within the bio-based polyester. This eliminates the need for the traditional method of melt modification of the talc masterbatch and bio-based polyester using a twin-screw extruder. Therefore, the talc masterbatch and bio-based polyester of this application can be mixed evenly in one step and then extruded through a single-screw extruder, eliminating the need for the melt modification step in a twin-screw extruder. This simplifies the traditional two-step process of twin-screw modification and single-screw extrusion into a one-step extrusion. This not only avoids the damage to the mechanical properties of bio-based polyester caused by the strong shear field of the twin-screw extruder and the problem of reduced melt strength, but also effectively preserves the original toughness and ductility of the bio-based polyester and greatly improves production efficiency.

[0087] Specifically, the set temperatures of the single-screw extruder from the feed port to the die head are as follows: Zone 1 temperature 160℃, Zone 2 temperature 170℃, Zone 3 temperature 170℃, Zone 4 temperature 175℃, Zone 5 temperature 175℃, Zone 6 temperature 170℃, and the screw speed is 45r / min.

[0088] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials: Talc powder A: 92-10-TZ1, particle size D90 is 10μm, whiteness is 92, silica content is 60%, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder B: 92-6-TZ1, particle size D90 is 6μm, whiteness is 92, silica content is 60%, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder C: 92-3-TZ1, particle size D90 is 3μm, whiteness is 92, silica content is 60%, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder D: 92-2.5-TZ1, particle size D90 is 2.5μm, whiteness is 92, silica content is 60% by mass, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder E: 92-2-TZ1, particle size D90 is 2μm, whiteness is 92, silica content is 60%, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder F: 92-1.5-TZ1, particle size D90 is 1.5μm, whiteness is 92, and silica content is 60% by mass. It was purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder G: 92-10-TZ2, particle size D90 is 10μm, whiteness is 92, silica content is 61% by mass, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder H: 92-10-TZ3, particle size D90 is 10μm, whiteness is 92, silica content is 62% by mass, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder I: 92-12-TZ1, with a particle size D90 of 14μm, whiteness of 92, and silica content of 60%, was purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Talc powder J: 92-10-TZ0, particle size D90 is 10μm, whiteness is 92, silica content is 57% by mass, purchased from Guangxi Huamei Chuangyuan New Material Technology Co., Ltd. Polylactic acid (PLA): melt index of 5 g / 10 min at 190℃ and 2.16 kg, REVODE 110, purchased from Zhejiang Hisun Biomaterials Co., Ltd. Polyhydroxyalkanoate: PB3430G, purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd.

[0089] Chain extender: BTCE-9370, Nanjing Baitong New Materials Co., Ltd.; Antioxidant: A mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1. Both antioxidant 1010 and antioxidant 168 are commercially available products.

[0090] Example 1 <Preparation of the First Modified Talc> Castor oil was heated at 80°C for 1 hour to obtain castor oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.8 parts by weight of KH550 and 0.5 parts by weight of ethanol were added to a high-speed mixer and mixed for 5 minutes at a temperature of 120°C and a speed of 800 r / min. Then, 0.8 parts by weight of castor oil at a temperature of 80°C were added and mixed for 10 minutes at a temperature of 120°C and a speed of 800 r / min to obtain the first modified talc powder.

[0091] <Preparation of the Second Modified Talc> Epoxidized soybean oil was heated at 80°C for 1 hour to obtain epoxidized soybean oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.8 parts by weight of KH550 and 0.5 parts by weight of ethanol were added to a high-speed mixer and mixed for 5 minutes at a temperature of 120°C and a speed of 800 r / min. Then, 0.8 parts by weight of epoxidized soybean oil at an oil temperature of 80°C were added and mixed for 10 minutes at a temperature of 120°C and a speed of 800 r / min to obtain the second modified talc powder.

[0092] <Preparation of Talc Masterbatch> Add 20 parts by weight of polylactic acid (PLA), 0.8 parts by weight of chain extender and 0.8 parts by weight of antioxidant to a mixer and mix at 60 r / min for 5 min to obtain a mixture; Add the mixture, 30 parts by weight of the first modified talc powder and 50 parts by weight of the second modified talc powder to a mixer with a bottom temperature of 200°C and mix at a speed of 40 r / min. Stop mixing when the material temperature reaches 180°C to obtain talc masterbatch premix. Talc masterbatch premix is ​​added to a single-screw extruder for melt extrusion granulation to obtain talc masterbatch. The set temperatures of the single-screw extruder from the feed port to the die head are as follows: Zone 1: 160℃, Zone 2: 170℃, Zone 3: 170℃, Zone 4: 175℃, Zone 5: 175℃, Zone 6: 170℃, and the screw speed is 45 r / min.

[0093] <Preparation of Bio-based Polyester Composite Materials> 75 parts by weight of polyhydroxyalkanoate (PHA) were dried at 80°C for 4 hours, and then mixed with 25 parts by weight of talc masterbatch in a low-speed mixer at 60 r / min for 5 minutes. Bio-based polyester composite materials were obtained by melt extrusion granulation using a single-screw extruder. The set temperatures of the single-screw extruder from the feed port to the die head were as follows: Zone 1: 160℃, Zone 2: 170℃, Zone 3: 170℃, Zone 4: 175℃, Zone 5: 175℃, Zone 6: 170℃, and the screw speed was 45 r / min.

[0094] <Preparation of Biodegradable Straws> 75 parts by weight of polyhydroxyalkanoate (PHA) were dried at 80°C for 4 hours, and then mixed with 25 parts by weight of talc masterbatch in a low-speed mixer at 60 r / min for 5 minutes. A single-screw extruder with a straw preform die is used to melt-extrude straw preforms. The preforms are then sequentially passed through water cooling, air cooling, dehydration, and cutting devices under traction to obtain PHA biodegradable straws. The temperature settings of the single-screw extruder from the feed port to the die head are as follows: Zone 1: 160℃, Zone 2: 170℃, Zone 3: 170℃, Zone 4: 175℃, Zone 5: 175℃, Zone 6: 170℃, and the screw speed is 45 r / min.

[0095] Example 2 The difference between this embodiment and Embodiment 1 is that the weight parts of KH550 and castor oil in <Preparation of the first modified talc> and the weight parts of KH550 and epoxidized soybean oil in <Preparation of the second modified talc> are different; all other aspects are the same as in Embodiment 1. In the preparation of the first modified talc powder, the weight parts of KH550 are 0.5 parts and the weight parts of castor oil are 1.1 parts. In the preparation of the second modified talc powder, the weight parts of KH550 are 0.5 parts and the weight parts of epoxidized soybean oil are 1.1 parts.

[0096] Example 3 The difference between this embodiment and Embodiment 1 is that the weight parts of KH550 and castor oil in <Preparation of the first modified talc> and the weight parts of KH550 and epoxidized soybean oil in <Preparation of the second modified talc> are different; all other aspects are the same as in Embodiment 1. In the preparation of the first modified talc powder, the weight parts of KH550 are 1.1 parts and the weight parts of castor oil are 0.5 parts. In the preparation of the second modified talc powder, the weight parts of KH550 are 1.1 parts and the weight parts of epoxidized soybean oil are 0.5 parts.

[0097] Example 4 The difference between this embodiment and Embodiment 1 is that the weight parts of KH550 and castor oil in <Preparation of the first modified talc> and the weight parts of KH550 and epoxidized soybean oil in <Preparation of the second modified talc> are different; all other aspects are the same as in Embodiment 1. In the preparation of the first modified talc powder, the weight parts of KH550 are 1.3 parts and the weight parts of castor oil are 0.3 parts. In the preparation of the second modified talc powder, the weight parts of KH550 are 1.3 parts and the weight parts of epoxidized soybean oil are 0.3 parts.

[0098] Example 5 The difference between this embodiment and Embodiment 1 is that the weight parts of KH550 and castor oil in <Preparation of the first modified talc> and the weight parts of KH550 and epoxidized soybean oil in <Preparation of the second modified talc> are different; all other aspects are the same as in Embodiment 1. In the preparation of the first modified talc powder, the weight parts of KH550 are 0.3 parts and the weight parts of castor oil are 1.3 parts. In the preparation of the second modified talc powder, the weight parts of KH550 are 0.3 parts and the weight parts of epoxidized soybean oil are 1.3 parts.

[0099] Example 6 The difference between this embodiment and Embodiment 1 is that ethanol is not included in <Preparation of the First Modified Talc> and <Preparation of the Second Modified Talc>, that is, the weight of ethanol in <Preparation of the First Modified Talc> and <Preparation of the Second Modified Talc> is 0 parts; all other aspects are the same as in Embodiment 1.

[0100] Example 7 The difference between this embodiment and Embodiment 1 is that talc powder B (D90=6μm) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest is the same as in Embodiment 1.

[0101] Example 8 The difference between this embodiment and Embodiment 1 is that talc powder C (D90=3μm) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Embodiment 1.

[0102] Example 9 The difference between this embodiment and Example 1 is that talc powder D (D90=2.5μm) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest is the same as in Example 1.

[0103] Example 10 The difference between this embodiment and Embodiment 1 is that talc powder E (D90=2μm) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Embodiment 1.

[0104] Example 11 The difference between this embodiment and Embodiment 1 is that talc powder F (D90=1.5μm) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Embodiment 1.

[0105] Example 12 The difference between this embodiment and Embodiment 1 is that talc powder G (silica content 61%) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Embodiment 1.

[0106] Example 13 The difference between this embodiment and Embodiment 1 is that talc powder H (62% silica content) is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Embodiment 1.

[0107] Example 14 The difference between this embodiment and Embodiment 1 is that the weight proportions of the first modified talc and the second modified talc are different in <Preparation of Talc Masterbatch>; all other aspects are the same as in Embodiment 1. In this embodiment, the talc masterbatch contains 40 parts by weight of the first modified talc and 40 parts by weight of the second modified talc.

[0108] Example 15 The difference between this embodiment and Embodiment 1 is that the weight proportions of the first modified talc and the second modified talc are different in <Preparation of Talc Masterbatch>; all other aspects are the same as in Embodiment 1. In this embodiment, the talc masterbatch contains 50 parts by weight of the first modified talc and 30 parts by weight of the second modified talc.

[0109] Example 16 The difference between this embodiment and Embodiment 1 is that the weight proportions of chain extender and antioxidant in the talc masterbatch are different in <Preparation of Talc Masterbatch>. In this embodiment, the talc masterbatch contains 0.6 parts by weight of chain extender and 0.6 parts by weight of antioxidant.

[0110] Example 17 The difference between this embodiment and Embodiment 1 is that the weight proportions of the chain extender and antioxidant are different in the <Preparation of Talc Masterbatch>. In this embodiment, the talc masterbatch contains 1 part by weight of chain extender and 1 part by weight of antioxidant.

[0111] Comparative Example 1 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of third modified talc replace 30 parts by weight of first modified talc and 50 parts by weight of second modified talc. That is, the third modified talc scheme does not use separate surface treatment of castor oil and epoxidized soybean oil, but adopts a one-pot method. The preparation method of the third modified talc powder includes the following steps: Castor oil was heated at 80°C for 1 hour to obtain castor oil with an oil temperature of 80°C. Epoxidized soybean oil was heated at 80°C for 1 hour to obtain epoxidized soybean oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.8 parts by weight of KH550 and 0.5 parts by weight of ethanol were added to a high-speed mixer and mixed for 5 minutes at 120°C and 800 r / min. Then, 0.4 parts by weight of castor oil at 80°C and 0.4 parts by weight of epoxidized soybean oil at 80°C were added and mixed for 10 minutes at 120°C and 800 r / min to obtain the third modified talc powder.

[0112] Comparative Example 2 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of the first modified talc replace 30 parts by weight of the first modified talc and 50 parts by weight of the second modified talc; that is, this comparative example does not contain the second modified talc, and all other aspects are the same as in Example 1.

[0113] Comparative Example 3 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of the second modified talc replace 30 parts by weight of the first modified talc and 50 parts by weight of the second modified talc; that is, this comparative example does not contain the first modified talc, and all other aspects are the same as in Example 1.

[0114] Comparative Example 4 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of the fourth modified talc replace 30 parts by weight of the first modified talc and 50 parts by weight of the second modified talc; the rest are the same as in Example 1. The preparation method of the fourth modified talc powder includes the following steps: 100 parts by weight of talc powder A, 1.6 parts by weight of KH550 and 0.5 parts by weight of ethanol were added to a high-speed mixer and mixed for 10 minutes at a temperature of 120℃ and a speed of 800 r / min to obtain the fourth modified talc powder. The fourth modified talc powder was not modified with castor oil and epoxidized soybean oil.

[0115] Comparative Example 5 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of the fifth modified talc replace 30 parts by weight of the first modified talc and 50 parts by weight of the second modified talc; the rest are the same as in Example 1. The fifth method for preparing modified talc includes the following steps: Castor oil was heated at 80°C for 1 hour to obtain castor oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.5 parts by weight of ethanol and 1.6 parts by weight of castor oil at 80°C were added to a high-speed mixer and mixed for 10 minutes at 120°C and 800 r / min to obtain the fifth modified talc powder. The fifth modified talc powder was modified without silane coupling agent KH550 and epoxidized soybean oil.

[0116] Comparative Example 6 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 80 parts by weight of the sixth modified talc replace 30 parts by weight of the first modified talc and 50 parts by weight of the second modified talc; the rest are the same as in Example 1. The preparation method of the sixth modified talc powder includes the following steps: Epoxidized soybean oil was heated at 80°C for 1 hour to obtain epoxidized soybean oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.5 parts by weight of ethanol and 1.6 parts by weight of epoxidized soybean oil at 80°C were mixed for 10 minutes at 120°C and 800 r / min to obtain the sixth modified talc powder. The sixth modified talc powder was modified without silane coupling agent KH550 and castor oil.

[0117] Comparative Example 7 The difference between this comparative example and Example 1 is that in the <Preparation of Talc Masterbatch>, 30 parts by weight of the fifth modified talc replace 30 parts by weight of the first modified talc, and 50 parts by weight of the sixth modified talc replace 50 parts by weight of the second modified talc; neither the fifth nor the sixth modified talc is treated with a silane coupling agent. The fifth method for preparing modified talc includes the following steps: Castor oil was heated at 80°C for 1 hour to obtain castor oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.5 parts by weight of ethanol and 1.6 parts by weight of castor oil at 80°C were added to a high-speed mixer and mixed for 10 minutes at 120°C and 800 r / min to obtain the fifth modified talc powder.

[0118] The preparation method of the sixth modified talc powder includes the following steps: Epoxidized soybean oil was heated at 80°C for 1 hour to obtain epoxidized soybean oil with an oil temperature of 80°C. 100 parts by weight of talc powder A, 0.5 parts by weight of ethanol and 1.6 parts by weight of epoxidized soybean oil at 80°C were mixed for 10 minutes at 120°C and 800 r / min to obtain the sixth modified talc powder.

[0119] Comparative Example 8 The difference between this comparative example and Example 1 is that talc powder I is used instead of talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Example 1.

[0120] Comparative Example 9 The difference between this comparative example and Example 1 is that talc powder J is used to replace talc powder A in both <Preparation of the first modified talc powder> and <Preparation of the second modified talc powder>; the rest are the same as in Example 1.

[0121] Comparative Example 10 The difference between this comparative example and Example 1 is that in the <Preparation of Bio-based Polyester Composite Material>, commercially available talc masterbatch 1 is used instead of talc masterbatch. The parameters of commercially available talc masterbatch 1 are as follows: the carrier is polylactic acid (PLA), the talc content is 80%, the talc particle size D90 is 10μm, the silica content in the talc is 60%, and it was purchased from Company A in Shanghai.

[0122] Comparative Example 11 The difference between this comparative example and Example 1 is that in the <Preparation of Bio-based Polyester Composite Material>, commercially available talc masterbatch 2 is used instead of talc masterbatch. The parameters of commercially available talc masterbatch 2 are as follows: the carrier is polybutylene terephthalate (PBAT), the talc content is 70%, the talc particle size D90 is 10μm, and the silica content in the talc is 60%. It was purchased from Zhejiang Company B.

[0123] Comparative Example 12 The difference between this comparative example and Example 1 is that the <Preparation of bio-based polyester composite material> and <Preparation of biodegradable straws> are different; This comparative example, <Preparation of Bio-based Polyester Composite Material>, includes the following steps: 80 parts by weight of polyhydroxyalkanoate (PHA) were dried at 80°C for 4 hours. Then, 0.8 parts of chain extender, 0.8 parts of antioxidant, 7.5 parts of first modified talc and 12.5 parts of second modified talc were added and mixed in a low-speed mixer at 60 r / min for 5 minutes to obtain a mixture. The mixture is added to a twin-screw extruder for melt extrusion granulation to obtain a bio-based polyester composite material. The set temperatures of the twin-screw extruder from the feed port to the die head are as follows: Zone 1: 160℃; Zones 2-4: 170℃; Zones 5-7: 170℃; Zones 8-9: 175℃; Zone 10: 170℃; and the screw speed is 200 r / min.

[0124] This comparative example, <Preparation of Biodegradable Straws>, includes the following steps: The talc-modified bio-based polyester composite material prepared above was dried at 80°C for 4 hours, and then extruded into a preform through a single-screw extruder with a straw preform die. The preform was then passed through a water-cooling, air-cooling, dehydration, and cutting device in sequence under the traction equipment to obtain a biodegradable straw. The set temperatures of the single-screw extruder from the feed port to the die head were as follows: Zone 1: 160°C, Zone 2: 170°C, Zone 3: 170°C, Zone 4: 175°C, Zone 5: 175°C, Zone 6: 170°C, and the screw speed was 45 r / min.

[0125] Performance testing (1) Tensile strength and nominal strain at break: The bio-based polyester composite material was tested according to standard GB / T1040.2-2022; the tensile yield A method was adopted, the 1A type specimen was 4×10mm, and the test speed was 50mm / min; (2) Flexural strength and flexural modulus: The bio-based polyester composite material was tested according to standard GB / T9341-2008, with a size of 4×10mm and a test speed of 2mm / min; (3) Notched impact strength of cantilever beam: The bio-based polyester composite material was tested according to the standard GB / T1843-2008, with notch type A 4×10mm; (4) Melt index: The bio-based polyester composite material particles were dried at 80°C for 4 hours and then tested according to standard GB / T3682.1-2018. The test conditions were: 190°C, 2.16 kg. (5) Bending resistance: Fold 20 biodegradable straws in half 5 times and observe the breakage at the fold. The number of breaks is used to evaluate the bending resistance. The more breaks, the worse the bending resistance. (6) Formability: Based on the distance of 30cm between the extruder die and the water tank, the ease with which the melt preform can be pulled into the water tank for shaping is as follows: Excellent: The preform can be pulled into the water tank for shaping with no or slight drooping (drooping height ≤1cm); Good: The preform can be pulled into the water tank for shaping with a small drooping (drooping height ≤2cm); Medium: The preform can be pulled into the water tank for shaping with a significant drooping (drooping height ≤3cm); Poor: The preform drooping height is greater than 3cm or the melt has broken before the preform is pulled into the water tank.

[0126] (7) Dispersibility: Cut the biodegradable straw and observe the agglomeration state of talc in the cross-section using a scanning electron microscope (SEM). The cross-section morphology is almost agglomerated, which is good; a little agglomerated is good; a lot of agglomerated particles appear, but no visible defects are visible, which is medium; a large area of ​​talc agglomerated particles appear in the SEM cross-section morphology, and visible defects are visible, which is poor.

[0127] The results are shown in Table 1.

[0128] Table 1 As can be seen from the experimental data in Table 1, the bio-based polyester composite material prepared using the talc masterbatch of this application has high mechanical properties, the prepared biodegradable straw has high bending resistance and formability, and the talc powder has high dispersibility in the biodegradable straw.

[0129] The experimental data from Examples 1-5 show that, based on 100 parts by weight of the first talc powder, the first aminosilane coupling agent is 0.3-1.3 parts by weight, and the castor oil is 0.3-1.3 parts by weight; based on 100 parts by weight of the second talc powder, the second aminosilane coupling agent is 0.3-1.3 parts by weight, and the epoxidized soybean oil is 0.3-1.3 parts by weight. The resulting bio-based polyester composite material has a good balance of rigidity and toughness, that is, it has excellent rigidity and good toughness, and at the same time meets the requirements of extrusion straws. The resulting biodegradable straws have excellent formability, good bending resistance, and good dispersion of talc powder.

[0130] The experimental data from Examples 1 and 6 show that adding a dispersant to the first modified talc powder and the second modified talc powder is beneficial to the dispersibility of the first talc powder and the first aminosilane coupling agent, the second talc powder and the second aminosilane coupling agent, and is beneficial to improving the grafting modification effect of castor oil or epoxidized soybean oil.

[0131] Experimental data from Examples 1, 7-10, and Comparative Example 8 show that the particle size D90 of both the first and second talc powders is greater than 10 μm, resulting in lower mechanical properties of the obtained bio-based polyester composite material, moderate flexural strength of the biodegradable straw, and only good formability. Furthermore, the mechanical properties of Examples 7 (talc D90 = 6 μm) and 8 (talc D90 = 3 μm) are superior to those of Example 1 (talc D90 = 10 μm), while other comprehensive properties are basically equivalent. Although the mechanical properties of Examples 9 (talc D90 = 2.5 μm) and 10 (talc D90 = 2 μm) are even better, their dispersibility decreases from good to medium, indicating that as the talc particle size D90 decreases below 2.5 μm, the talc powder is prone to agglomeration and poor dispersion due to its small particle size. This indicates that only when the particle size D90 of the first and second talc powders is 2.5-6μm can a bio-based polyester composite material with good mechanical properties, high formability, bending resistance and good talc powder dispersibility be obtained as a biodegradable straw.

[0132] The experimental data from Examples 1, 11-13 and Comparative Example 9 show that when the silica content in the first talc powder and the second talc powder is less than 60%, the mechanical properties of the resulting bio-based polyester composite material decrease, and the bending resistance of the biodegradable straw decreases, but it does not affect the moldability or the dispersibility of the talc powder. This indicates that only when the silica content in the first talc powder and the second talc powder is ≥60% can a bio-based polyester composite material with good mechanical properties and a biodegradable straw with good bending resistance be obtained.

[0133] The experimental data from Example 1 and Comparative Example 1 show that if aminosilane coupling agent, castor oil, and epoxidized soybean oil are used to modify talc powder simultaneously, incomplete modification reaction will occur. The resulting bio-based polyester composite material has a flexural strength of 43.2 MPa and a notched cantilever beam impact strength of 4.1 kJ / m. 2 The biodegradable straws exhibit poor bending resistance. This indicates that only by preparing talc masterbatches using first modified talc (which is pretreated with a first aminosilane coupling agent and then grafted with castor oil) and second modified talc (which is pretreated with a second aminosilane coupling agent and then grafted with epoxidized soybean oil) can the toughness of the bio-based polyester composite material and the bending resistance of the biodegradable straws be improved while maintaining the rigidity of the bio-based polyester composite material.

[0134] The experimental data from Examples 1 and Comparative Examples 2-3 show that, in the absence of the first or second modified talc, the cantilever beam notched impact strength of the resulting bio-based polyester composite material is ≤3.8 kJ / m. 2The biodegradable straws have poor bending resistance, and the talc powder dispersibility in the biodegradable straws is medium. This indicates that only by adding the first modified talc powder and the second modified talc powder simultaneously can the toughness of the biodegradable polyester composite material be improved, as well as the bending resistance of the biodegradable straws and the dispersibility of talc powder in the biodegradable straws, be maintained while maintaining the rigidity of the biodegradable polyester composite material.

[0135] The experimental data from Examples 1 and Comparative Examples 4-7 show that, without modification of talc by at least one of aminosilane coupling agent, castor oil, and epoxidized soybean oil, the cantilever beam notched impact strength of the resulting bio-based polyester composite material is ≤3.3 kJ / m. 2 The biodegradable straws exhibit poor flexural strength and average formability. The dispersibility of talc powder in the biodegradable straws is also average. This indicates that only by preparing talc masterbatches with first modified talc powder (the first talc powder is pretreated with a first aminosilane coupling agent and then grafted with castor oil) and second modified talc powder (the second talc powder is pretreated with a second aminosilane coupling agent and then grafted with epoxidized soybean oil) can the toughness of the bio-based polyester composite material and the flexural strength of the biodegradable straws be improved while maintaining the rigidity of the bio-based polyester composite material.

[0136] The experimental data from Examples 1 and Comparative Examples 10-11 show that, compared with the talc masterbatch of this application, the flexural strength of the bio-based polyester composite material prepared from commercially available talc masterbatch is ≤40.3MPa, and the notched cantilever beam impact strength is ≤3.4kJ / m. 2 The biodegradable straws exhibit poor flexural strength and medium formability. The talc powder in the biodegradable straws also shows poor dispersibility. This indicates that the talc masterbatch of this application can significantly improve the flexural strength and cantilever beam notched impact strength of the bio-based polyester composite material, as well as improve the flexural strength, formability, and dispersibility of the talc powder in the biodegradable straws.

[0137] The experimental data from Example 1 and Comparative Example 12 show that Comparative Example 12 uses a traditional twin-screw extruder to prepare biodegradable straws. Compared with Comparative Example 12, the talc masterbatch of this application improves the problem of a significant decrease in the toughness of bio-based polyester composite materials. Furthermore, the talc masterbatch of this application can be used to directly prepare biodegradable straws in a one-step process with bio-based polyester, eliminating the material melt modification step of the twin-screw extruder. This avoids the problem of the strong shear field of the twin-screw extruder weakening the mechanical properties of biodegradable plastics and causing a significant decrease in melt strength, thus greatly preserving the original toughness and ductility of biodegradable plastics.

[0138] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of this application and not to limit the scope of protection of this application. Although this application 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 this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A talc masterbatch, characterized in that, The components include the following parts by weight: Polylactic acid 15-30 parts, first modified talc 30-50 parts, second modified talc 30-50 parts, additives 1.2-2 parts; The first modified talc powder comprises first talc powder, first aminosilane coupling agent, and castor oil; The second modified talc powder includes a second talc powder, a second aminosilane coupling agent, and epoxidized soybean oil; The particle size D90 of both the first talc powder and the second talc powder is ≤10μm; The silica content in the first talc powder and the second talc powder is ≥60%.

2. The talc masterbatch as described in claim 1, characterized in that, The particle size D90 of the first talc powder and the second talc powder is independently 2-10 μm.

3. The talc masterbatch as described in claim 1, characterized in that, Based on 100 parts by weight of the first talc powder, the first aminosilane coupling agent comprises 0.3-1.3 parts by weight, and the castor oil comprises 0.3-1.3 parts by weight.

4. The talc masterbatch as described in claim 1, characterized in that, Based on 100 parts by weight of the second talc powder, the second aminosilane coupling agent comprises 0.3-1.3 parts by weight, and the epoxidized soybean oil comprises 0.3-1.3 parts by weight.

5. The talc masterbatch as described in claim 1, characterized in that, The first modified talc powder and the second modified talc powder further include a dispersant, wherein the dispersant comprises 0.5-1 parts by weight of 100 parts by weight of the first talc powder and 0.5-1 parts by weight of the second talc powder.

6. The talc masterbatch as described in claim 1, characterized in that, The whiteness of the first talc powder and the second talc powder is ≥90.

7. The talc masterbatch as described in claim 1, characterized in that, The adjuvants include at least one of antioxidants and chain extenders; And / or, the first aminosilane coupling agent and the second aminosilane coupling agent are each independently selected from at least one of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

8. A method for preparing talc masterbatch as described in any one of claims 1 to 7, characterized in that, Includes the following steps: After the components are mixed evenly in proportion, they are kneaded in an internal mixer to obtain a premix. The premixed material is added to a single-screw extruder and melt-extruded to granulate, thus obtaining talc masterbatch.

9. A bio-based polyester composite material, characterized in that, The components include the following parts by weight: 70-98 parts of bio-based polyester and 2-30 parts of talc masterbatch as described in any one of claims 1-7.

10. A biodegradable straw, characterized in that, Including the bio-based polyester composite material as described in claim 9.

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