A highly transparent and high-barrier bio-based copolymer nylon composite material and its preparation method

Abstract

This invention relates to the field of nylon resin and its composite materials, and particularly to a highly transparent and highly barrier bio-based copolymer nylon composite material and its preparation method. This bio-based copolymer nylon composite material is prepared from raw materials including bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and a first auxiliary agent. This bio-based nylon composite material exhibits excellent transparency, barrier properties, and solvent resistance, and also possesses excellent heat resistance, mechanical properties, and toughness, showing broad application prospects in food packaging, medical devices, smart wearable electronics, and flexible displays.

Description

Technical Field

[0001] This invention relates to the field of nylon resin and its composite materials, and in particular to a highly transparent and highly barrier bio-based copolymer nylon composite material and its preparation method. Background Technology

[0002] Polyamide (PA), commonly known as nylon, is a widely used engineering plastic. Due to its excellent mechanical properties, lubrication resistance, and ease of modification, it is widely used in the automotive, electronics, and textile industries. Currently, the products made from petroleum-based nylons such as aromatic nylon 6, nylon 66, and semi-aromatic nylon 46, nylon 6T, and nylon 9T, which are widely used in industry, are primarily derived from the reprocessing of petroleum refining byproducts. This results in a high dependence on petroleum and environmental pollution during the manufacturing process. Therefore, bio-based nylon materials prepared using renewable biomass resources have attracted widespread attention.

[0003] Bio-based nylon materials refer to materials produced from renewable biomass resources (such as glucose, cellulose, and vegetable oils) through bioengineering methods, using the raw materials needed to produce nylon (generally diacids, diamines, or lactams). Common bio-based nylon materials include nylon 56, nylon 510, nylon 5T, and nylon 11, and have numerous applications in food packaging, clothing fibers, natural gas pipelines, medical protective goggles, automotive fuel lines, and machinery.

[0004] Transparent nylon, a type of specialty nylon, is widely used in food packaging, electronics, machinery, and optics due to its high transparency, solvent resistance, low density, abrasion resistance, and flexibility. However, traditional transparent nylons typically employ an amorphous aggregate structure, such as nylon TMDT and nylon CM12. This amorphous aggregate structure achieves good transparency by disrupting the regularity of the molecular chains. However, this amorphous aggregate structure makes it difficult for transparent nylon to block the penetration of polar solvents or water vapor, resulting in poor barrier properties and solvent resistance, thus limiting its applications. Examples include medical devices requiring high-temperature steam sterilization, food packaging, and smart wearable electronics and flexible displays that require frequent contact with polar solvents for cleaning. Chinese patent publication CN 101768302 A discloses a method for preparing a high-barrier polyethylene / nylon 6 in-situ nanocomposite material. This method uses a screw extruder to react and extrude polyethylene, caprolactam, intercalated montmorillonite, a compatibilizer, an anionic initiator, and a co-catalyst together to prepare the high-barrier polyethylene / nylon 6 in-situ nanocomposite material. However, this patent adds montmorillonite during the preparation process. The addition of montmorillonite results in poor transparency of the high-barrier polyethylene / nylon 6 in-situ nanocomposite material, limiting its application in food packaging, medical devices, smart wearable electronics, and flexible displays.

[0005] Therefore, how to obtain a bio-based nylon material that combines excellent transparency, barrier properties, and solvent resistance is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention provides a highly transparent and highly barrier bio-based copolymer nylon composite material. This bio-based nylon composite material has excellent transparency, barrier properties and solvent resistance, and also has excellent heat resistance, mechanical properties and toughness.

[0007] The present invention also provides a method for preparing a highly transparent and highly barrier bio-based copolymer nylon composite material, which can be used to prepare a bio-based nylon composite material with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties and toughness.

[0008] The first aspect of the present invention provides a highly transparent and highly barrier bio-based copolymer nylon composite material, wherein the raw materials for preparing the bio-based nylon composite material include bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant and a first auxiliary agent;

[0009] The bio-based copolymer nylon resin is either bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 512.

[0010] The high-transparency, high-barrier bio-based copolymer nylon composite material described above, by weight, comprises, in the raw materials, 92 to 98 parts of the bio-based copolymer nylon resin, 1 to 5 parts of the nanocellulose, 1 to 5 parts of the compatibilizer, 0.1 to 0.5 parts of the antioxidant, and 0.1 to 2 parts of the first auxiliary agent.

[0011] The high-transparency, high-barrier bio-based copolymer nylon composite material described above has a relative viscosity of 2.42–2.56 for the bio-based copolymer nylon resin 5T / 510 and a relative viscosity of 2.61–2.63 for the bio-based copolymer nylon resin 5T / 512.

[0012] The highly transparent and highly barrier bio-based copolymer nylon composite material described above has a nanocellulose length of less than 300 nm.

[0013] The highly transparent and highly barrier bio-based copolymer nylon composite material described above has a carboxyl content of 1.2 mmol / g to 3.0 mmol / g in the nanocellulose.

[0014] The highly transparent and highly barrier bio-based copolymer nylon composite material described above, wherein the compatibilizer is at least one of ethylene acrylate copolymer, ethylene-octene copolymer grafted maleic anhydride, and glycidyl methacrylate grafted modified polyether block amide copolymer.

[0015] And / or, the antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant TNP, and antioxidant TPP;

[0016] And / or, the first additive includes a lubricant.

[0017] The preparation process of the bio-based copolymer nylon resin for the high-transparency, high-barrier bio-based copolymer nylon composite material described above is as follows:

[0018] A mixed solution of nylon 5T salt was obtained by mixing dicarboxylic acid, terephthalic acid and deionized water and then adding 1,5-pentanediamine for neutralization.

[0019] The catalyst, end-capping agent, second auxiliary agent and the nylon 5T salt mixed solution are concentrated and prepolymerized to obtain nylon 5T prepolymer;

[0020] The nylon 5T prepolymer was polymerized under vacuum negative pressure to obtain a bio-based copolymer nylon resin.

[0021] In the above-described high-transparency, high-barrier bio-based copolymer nylon composite material, the dicarboxylic acid is sebacic acid or dodecanoic acid;

[0022] When the dicarboxylic acid is sebacic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 510.

[0023] When the dicarboxylic acid is dodecanoic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 512.

[0024] A second aspect of the present invention provides a method for preparing the aforementioned highly transparent and highly barrier bio-based copolymer nylon composite material, comprising:

[0025] Preparation of bio-based copolymer nylon resin;

[0026] Preparation of bio-based copolymer nylon composite materials:

[0027] The bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant and first auxiliary agent are mixed and dispersed to obtain a mixture. The mixture is then melt-extruded, drawn and granulated in a screw extruder to obtain a bio-based copolymer nylon composite material.

[0028] In the preparation method of the high-transparency, high-barrier bio-based copolymer nylon composite material described above, the melt extrusion temperature is 260℃~280℃.

[0029] The present invention provides a highly transparent and highly barrier bio-based copolymer nylon composite material, which is prepared from raw materials including bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and a first auxiliary agent. This bio-based nylon composite material has a light transmittance of up to 91.8% and can effectively block the penetration of oxygen, water vapor, and polar solvents (N,N-dimethylformamide in the embodiments of the present invention), demonstrating that the bio-based nylon composite material has excellent transparency, barrier properties, and solvent resistance. Furthermore, it also exhibits excellent heat resistance (glass transition temperature up to 109°C), mechanical properties (tensile strength up to 91 MPa), and toughness (flexural strength up to 158 MPa), showing broad application prospects in food packaging, medical devices, smart wearable electronics, and flexible displays. In addition, compared with traditional petroleum-based nylon materials, this bio-based copolymer nylon composite material is an environmentally friendly material. Attached Figure Description

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1The infrared spectrum of PA5T / 510 in Embodiment 1 of the present invention;

[0032] Figure 2 The infrared spectrum of the bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention;

[0033] Figure 3 The X-ray diffraction pattern of PA5T / 510 and bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention;

[0034] Figure 4 The image shows the DSC thermal analysis test result of PA5T / 510 and bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention.

[0035] Figure 5 The bio-based copolymer nylon composite materials after soaking in Examples 1-4 of this invention;

[0036] Figure 6 These are the bio-based copolymer nylon composite materials after soaking in Comparative Examples 1-4 of the present invention;

[0037] Figure 7 The bio-based copolymer nylon composite materials of Comparative Examples 5-6 of this invention were soaked. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available; and the processes used are conventional processes in the art.

[0040] It should be noted that the use of terms such as "first" and "second" in this invention is for distinguishing similar objects and not for describing a specific order or sequence, and therefore should not be construed as a limitation of this invention.

[0041] Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0042] The first aspect of the present invention provides a highly transparent and highly barrier bio-based copolymer nylon composite material, wherein the raw materials for preparing the bio-based nylon composite material include bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant and a first auxiliary agent;

[0043] The bio-based copolymer nylon resin is either bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 512.

[0044] Specifically, the bio-based copolymer nylon composite material of the present invention can be prepared from raw materials including bio-based copolymer nylon resin 5T / 510, nanocellulose, compatibilizer, antioxidant and first auxiliary agent, or it can be prepared from raw materials including bio-based copolymer nylon resin 5T / 512, nanocellulose, compatibilizer, antioxidant and first auxiliary agent. The bio-based copolymer nylon composite material has excellent transparency (light transmittance up to 91.8%), barrier properties (effectively blocking the penetration of oxygen and water vapor) and solvent resistance (effectively blocking the penetration of polar solvents), and it also has excellent heat resistance (glass transition temperature up to 109°C), mechanical properties (tensile strength up to 91 MPa) and toughness (flexural strength up to 158 MPa). The inventors analyzed this and believed that the reasons might be: (1) The crystal form of bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 510 is similar to that of nanocellulose, which greatly reduces the interfacial reflection and diffraction phenomena between nanocellulose and bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 510, making it easier for light to penetrate the material and achieve high transmittance. Therefore, the bio-based copolymer nylon composite material has excellent transparency; (2) The design of heterogeneous dicrystalline co-crystallized aggregate structure results in a longer carbon chain. Therefore, the prepared bio-based copolymer nylon composite material has advantages such as strong barrier properties, excellent solvent resistance, excellent heat resistance, excellent mechanical properties, and excellent toughness.

[0045] The present invention does not impose any particular limitation on the source of the raw materials used above. They can be obtained through commercial channels or prepared by methods well known in the art.

[0046] In one specific embodiment, by weight, the above-mentioned raw materials include 92 to 98 parts of bio-based copolymer nylon resin, 1 to 5 parts of nanocellulose, 1 to 5 parts of compatibilizer, 0.1 to 0.5 parts of antioxidant, and 0.1 to 2 parts of first auxiliary agent.

[0047] When the proportions of bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and first auxiliary agent in the above-mentioned raw materials are within the above-mentioned range, the bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and first auxiliary agent can have a good synergistic effect, thereby preparing a bio-based copolymer nylon composite material with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties, and toughness.

[0048] In one specific embodiment, the relative viscosity of bio-based copolymer nylon resin 5T / 510 is 2.42 to 2.56, and the relative viscosity of bio-based copolymer nylon resin 5T / 512 is 2.61 to 2.63.

[0049] When the relative viscosity of the above-mentioned bio-based copolymer nylon resin 5T / 510 or the relative viscosity of the above-mentioned bio-based copolymer nylon resin 5T / 512 are within the above-mentioned range, a bio-based copolymer nylon composite material with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties and toughness can be prepared.

[0050] In one specific embodiment, the length of the above-mentioned nanocellulose is less than 300 nm, and more preferably 200 nm to 300 nm.

[0051] In one specific embodiment, the carboxyl content in the above-mentioned nanocellulose is 1.2 mmol / g to 3.0 mmol / g.

[0052] When the length of the nanocellulose and the carboxyl content in the nanocellulose are within the above range, a bio-based copolymer nylon composite material with high barrier properties and high transparency can be prepared. The inventors analyzed this and believe that the reason may be: (1) the carboxyl groups in the nanocellulose undergo amide exchange with the amide bonds in the bio-based copolymer nylon resin, forming a chemical graft. Due to the nanoscale effect of the nanocellulose, the prepared bio-based copolymer nylon composite material has high barrier properties against oxygen, water vapor and polar solvents; (2) the crystal form of the bio-based copolymer nylon resin 5T / 510 is similar to that of the nanocellulose, which greatly reduces the interfacial reflection and diffraction phenomena between the nanocellulose and the bio-based copolymer nylon resin 5T / 510, making it easier for light to penetrate the material, thus giving the bio-based copolymer nylon composite material high transparency.

[0053] In one specific embodiment, the compatibilizer is at least one of ethylene-acrylate copolymer, ethylene-octene copolymer grafted with maleic anhydride, and glycidyl methacrylate grafted with modified polyether block amide copolymer, preferably ethylene-octene copolymer grafted with maleic anhydride (POE-g-MAH). The antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant TNP, and antioxidant TPP. The first adjuvant includes a lubricant, preferably montmorillonite wax.

[0054] When the above-mentioned substances are selected as compatibilizers, antioxidants and first additives respectively, the components in the raw materials can be better matched, resulting in better synergistic effects and improving the overall performance of the above-mentioned bio-based copolymer nylon composite materials.

[0055] This invention does not specifically limit the method for preparing the bio-based copolymer nylon resin; it can be synthesized according to methods well known in the art or methods described in the literature. In one specific embodiment, the preparation process of the above-mentioned bio-based copolymer nylon resin is as follows:

[0056] A mixed solution of nylon 5T salt was obtained by mixing dicarboxylic acid, terephthalic acid and deionized water and then adding 1,5-pentanediamine for neutralization.

[0057] The catalyst, end-capping agent, second auxiliary agent and nylon 5T salt were mixed in a mixed solution and then concentrated and prepolymerized to obtain nylon 5T prepolymer.

[0058] The nylon 5T prepolymer was polymerized under vacuum negative pressure to obtain a bio-based copolymer nylon resin.

[0059] The present invention can prepare bio-based copolymer nylon resin according to the above preparation method.

[0060] In one specific embodiment, the dicarboxylic acid is sebacic acid or dodecanoic acid;

[0061] When the dicarboxylic acid is sebacic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 510.

[0062] When the dicarboxylic acid is dodecanoic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 512.

[0063] When the aforementioned dicarboxylic acid is sebacic acid or dodecanoic acid, bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 512 can be prepared, thereby using the bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 512 to prepare bio-based copolymer nylon composite materials with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties and toughness.

[0064] In some embodiments, the total amount of the dicarboxylic acid, terephthalic acid and 1,5-pentanediamine is 100 parts by weight, the catalyst is 0.2 to 1 part, the end-capping agent is 0.1 to 0.5 parts, and the second auxiliary agent is 0.05 to 0.5 parts.

[0065] In some embodiments, the molar ratio of the above-mentioned dicarboxylic acid, terephthalic acid and 1,5-pentanediamine is 4:1:5.

[0066] In some embodiments, the prepolymerization reaction is carried out at a temperature of 200°C to 250°C, a pressure of 1.5 MPa to 1.7 MPa, and a time of 1 hour to 2 hours.

[0067] In some embodiments, the polymerization reaction is carried out at a temperature of 240°C to 280°C for 1 hour to 1.5 hours, and the vacuum degree is -0.05 MPa to -0.08 MPa.

[0068] In some embodiments, the catalyst is at least one of sodium hypophosphite, sodium phosphite, phosphate ester and hypophosphite ester, the end-capping agent is at least one of benzoic acid, terephthalic acid and 2-naphthalic acid, and the second auxiliary agent includes a metal salt, preferably magnesium chloride.

[0069] A second aspect of the present invention provides a method for preparing a highly transparent and highly barrier bio-based copolymer nylon composite material, comprising:

[0070] Preparation of bio-based copolymer nylon resin;

[0071] Preparation of bio-based copolymer nylon composite materials:

[0072] Bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant and first auxiliary agent are mixed and dispersed to obtain a mixture. The mixture is then melt-extruded, drawn and granulated in a screw extruder to obtain a bio-based copolymer nylon composite material.

[0073] Specifically, this invention prepares a bio-based copolymer nylon composite material. First, the bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and a first auxiliary agent are mixed and dispersed to obtain a mixture. This mixing process facilitates the uniform dispersion and interaction of the various raw materials, providing a stable material basis for subsequent processing steps such as melt extrusion, traction, and granulation. Then, the mixture is placed in a screw extruder and subjected to melt extrusion, traction, and granulation to obtain a bio-based copolymer nylon composite material with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties, and toughness. This preparation method is simple and suitable for widespread application.

[0074] In one specific embodiment, the melt extrusion temperature is 260°C to 280°C.

[0075] When the temperature parameters of melt extrusion are within the above range, the melt viscosity of bio-based copolymer nylon resin can be effectively reduced, thereby improving its fluidity. This helps to improve the dispersibility of nanocellulose in bio-based copolymer nylon resin, allowing for more complete amide exchange between nanocellulose and bio-based copolymer nylon resin, forming more chemical grafts, promoting interfacial bonding between nanocellulose and bio-based copolymer nylon resin, and better exerting its reinforcing and modifying effects. This results in the preparation of bio-based copolymer nylon composite materials with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties, and toughness.

[0076] For example, the temperature of the melt extrusion can be any one or a combination of any two of 260°C, 265°C, 270°C, 275°C or 280°C.

[0077] This invention does not impose a particular limitation on the melt extrusion time, which can be selected according to actual needs. In some embodiments, the residence time of melt extrusion is greater than 15 minutes.

[0078] The present invention will be described in detail through the following examples and comparative examples. The raw materials involved in the embodiments and comparative examples of the present invention are: bio-based copolymer nylon resin 5T / 510 (PA5T / 510), bio-based copolymer nylon resin 5T / 512 (PA5T / 512), transparent nylon TR90 (purchased from EMS, Switzerland, molecular formula abbreviation PA MACM12), transparent nylon G21 (purchased from EMS, Switzerland, molecular formula abbreviation PA6I / 6T), nanocellulose A, nanocellulose B, nanocellulose C, nanocellulose D, ethylene-octene copolymer grafted maleic anhydride (POE-g-MAH), antioxidant 168, antioxidant 1010, and styrax wax. The raw material formulations are shown in Tables 1 and 2.

[0079] Table 1. Raw material formulas for Examples 1-4 (by weight parts)

[0080] serial number Example 1 Example 2 Example 3 Example 4 PA5T / 510 92 92 0 0 PA5T / 512 0 0 92 92 PA MACM12 0 0 0 0 PA6I / 6T 0 0 0 0 Nanocellulose A 3 0 3 0 Nanocellulose B 0 3 0 3 Nanocellulose C 0 0 0 0 Nanocellulose D 0 0 0 0 POE-g-MAH 4 4 4 4 Antioxidant 168 0.2 0.2 0.2 0.2 Antioxidant 1010 0.2 0.2 0.2 0.2 Montana wax 0.6 0.6 0.6 0.2

[0081] Table 2. Raw material formulas for Comparative Examples 1-6 (by weight).

[0082]

[0083]

[0084] In Tables 1 and 2, nanocellulose (CNF) A is C916570-6% carboxylated cellulose nanofiber with a length of 200 nm and a carboxyl content of 2.1 mmol / g; nanocellulose (CNF) B is C916412-carboxylated cellulose nanofiber powder with a length of 200 nm and a carboxyl content of 2.1 mmol / g; nanocellulose (CNF) C is carboxyl-free nanocellulose with a length of 200 nm; and nanocellulose (CNF) D is C916569-6% carboxylated nanocellulose with a length of 1000 nm and a carboxyl content of 2.1 mmol / g.

[0085] The bio-based copolymer nylon resin 5T / 510 used in the following embodiments of the present invention was prepared by the following process:

[0086] By weight, 55 parts sebacic acid, 11 parts terephthalic acid and 150 parts deionized water were mixed to obtain a mixed solution. The mixed solution was stirred at 120 rpm until it became a white suspension. The white suspension was then heated to 80°C and 34 parts 1,5-pentanediamine were added for neutralization reaction for 1 hour to obtain a salt solution. The pH of the salt solution was adjusted to 7.5 to obtain a mixed solution of nylon 5T salt and nylon 510 salt.

[0087] Two parts of sodium hypophosphite, 0.5 parts of benzoic acid, 0.5 parts of magnesium chloride (an auxiliary agent), and 100 parts of a mixed solution of nylon 5T salt and nylon 510 salt were mixed to obtain a mixture. The mixture was added to an autoclave, and the air inside the autoclave was replaced with nitrogen five times. Then, the temperature was raised to 150°C, and the pressure was kept stable at 1.5 MPa to concentrate the mixture until the water content was 20%, resulting in a concentrated mixture. The temperature was then raised to 230°C, and the pressure was kept stable at 1.6 MPa to allow the concentrated mixture to undergo a prepolymerization reaction for 1 hour, resulting in a nylon 5T / 510 prepolymer.

[0088] The nylon 5T / 510 prepolymer was polymerized at 260℃ for 1 hour under a vacuum of -0.06 MPa to obtain bio-based copolymer nylon resin 5T / 510 (PA5T / 510).

[0089] The bio-based copolymer nylon resin 5T / 512 used in the following embodiments of the present invention was prepared by the following process:

[0090] By weight, 58 parts of dodecanoic acid, 10 parts of terephthalic acid and 155 parts of deionized water were mixed to obtain a mixed solution. The mixed solution was stirred at 120 rpm until it became a white suspension. The white suspension was then heated to 80°C and 32 parts of 1,5-pentanediamine were added for neutralization reaction for 1 hour to obtain a salt solution. The pH of the salt solution was adjusted to 7.5 to obtain a mixed solution of nylon 5T salt and nylon 512 salt.

[0091] A mixture of 2 parts sodium hypophosphite, 0.5 parts benzoic acid, 0.5 parts magnesium chloride, and 100 parts a mixed solution of nylon 5T salt and nylon 512 salt was obtained. The mixture was then added to an autoclave, and the air inside the autoclave was replaced with nitrogen five times. The temperature was then raised to 150°C, and the pressure was kept stable at 1.5 MPa to concentrate the mixture until the water content was 20%, resulting in a concentrated mixture. The temperature was then raised to 230°C, and the pressure was kept stable at 1.6 MPa to allow the concentrated mixture to undergo a prepolymerization reaction for 1 hour, yielding a nylon 5T / 512 prepolymer.

[0092] The nylon 5T / 512 prepolymer was polymerized at 260℃ for 1 hour under a vacuum of -0.06 MPa to obtain bio-based copolymer nylon resin 5T / 512 (PA5T / 512).

[0093] Example 1

[0094] This embodiment prepares a bio-based copolymer nylon composite material through the following process:

[0095] Step S1: PA5T / 510, nanocellulose A, POE-g-MAH, antioxidant 168, antioxidant 1010 and montan wax are mixed and dispersed according to the raw material formulation of Example 1 in Table 1 to obtain a mixture; then the mixture is placed in a screw extruder with a length-to-diameter ratio of 68:1, and the mixture is melt extruded, drawn and granulated in the screw extruder to obtain a bio-based copolymer nylon composite material (PA5T / 510CNF). The melt extrusion temperature is 265°C and the melt extrusion residence time is 15 min.

[0096] Example 2

[0097] The preparation of the bio-based copolymer nylon composite material provided in this embodiment is basically the same as that in Example 1, except that:

[0098] The raw material formula is as follows: 92 parts PA5T / 510, 3 parts nanocellulose B, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0099] Example 3

[0100] The preparation of the bio-based copolymer nylon composite material provided in this embodiment is basically the same as that in Example 1, except that:

[0101] The raw material formula is as follows: 92 parts PA5T / 512, 3 parts nanocellulose A, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0102] Example 4

[0103] The preparation of the bio-based copolymer nylon composite material provided in this embodiment is basically the same as that in Example 1, except that:

[0104] The raw material formula is as follows: 92 parts PA5T / 512, 3 parts nanocellulose B, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0105] Comparative Example 1

[0106] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0107] The raw material formula is as follows: 92 parts PA MACM12, 3 parts nanocellulose A, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0108] Comparative Example 2

[0109] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0110] The raw material formula is as follows: 92 parts PA6I / 6T, 3 parts nanocellulose A, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0111] Comparative Example 3

[0112] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0113] The raw material formula is as follows: 92 parts PA5T / 510, 3 parts nanocellulose C, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0114] Comparative Example 4

[0115] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0116] The raw material formula is as follows: 92 parts PA5T / 510, 3 parts nanocellulose D, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0117] Comparative Example 5

[0118] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0119] The melt extrusion temperature is 220℃.

[0120] Comparative Example 6

[0121] The preparation of the bio-based copolymer nylon composite material provided in this comparative example is basically the same as that in Example 1, except that:

[0122] The raw material formula is: 95 parts PA5T / 510, 4 parts POE-g-MAH, 0.2 parts antioxidant 168, 0.2 parts antioxidant 1010, and 0.6 parts montan wax.

[0123] The melt extrusion temperature is 220℃.

[0124] Performance testing

[0125] 1. Infrared spectroscopy test

[0126] Figure 1 The infrared spectrum of PA5T / 510 in Embodiment 1 of the present invention; Figure 2 The infrared spectrum of the bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention is shown.

[0127] Depend on Figure 1 and Figure 2 It can be seen that, compared with PA5T / 510, the stretching vibration peak of the bio-based copolymer nylon composite material (PA5T / 510CNF) is 3280.15 cm⁻¹. -1 ) and CO stretching vibration peaks (in 1000-1350 cm⁻¹) -1 Within the range of strength increase, no obvious abnormal peaks or drastic changes in absorption peaks appeared in the infrared spectrum of the bio-based copolymer nylon composite material, indicating that there is no obvious interaction between nanocellulose A and PA5T / 510 after the addition of nanocellulose A, which shows that nanocellulose A and PA5T / 510 have good compatibility.

[0128] 2. X-ray diffraction (XRD) test

[0129] Figure 3The image shows the X-ray diffraction pattern of PA5T / 510 and bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention.

[0130] Depend on Figure 3 It can be seen that, compared with PA5T / 510, the peak area in the spectrum of the bio-based copolymer nylon composite material (PA5T / 510CNF) is increased, indicating that its crystal content is improved. This shows that the addition of nanocellulose A increases the content of crystalline phase in the bio-based copolymer nylon composite material, thereby improving the crystallinity of the bio-based copolymer nylon composite material, without changing the crystal structure of PA5T / 510. The inventors analyzed this and concluded that it may be because the crystal form of nanocellulose A is similar to that of PA5T / 510, so the addition of nanocellulose A did not change the crystal structure of PA5T / 510.

[0131] 3. DSC thermal analysis test

[0132] Figure 4 The image shows the DSC thermal analysis test results of PA5T / 510 and bio-based copolymer nylon composite material (PA5T / 510CNF) in Example 1 of this invention.

[0133] Depend on Figure 4 It can be seen that, compared with PA5T / 510, the melt peak area of ​​the bio-based copolymer nylon composite material (PA5T / 510CNF) is increased, and the melt peak area is directly proportional to the melting enthalpy (ΔHm) of the material. This indicates that the crystallinity of the bio-based copolymer nylon composite material (PA5T / 510CNF) increases after the addition of nanocellulose A, the crystallization process is more complete, the proportion of crystalline regions in the bio-based copolymer nylon composite material (PA5T / 510CNF) increases, and a more ordered crystal structure is formed, which is beneficial to improving the thermal stability and mechanical properties of the material.

[0134] 4. Solvent resistance test

[0135] The bio-based copolymer nylon composites of Examples 1-4 and Comparative Examples 1-6 were subjected to solvent resistance tests according to standard ISO 175. First, the mass of the bio-based copolymer nylon composites of each example and each comparative example before immersion was measured. Then, the bio-based copolymer nylon composites of each example and each comparative example were bent and the bent part was completely immersed in 99.8% N,N-dimethylformamide by mass. After immersion for 1 hour and drying, the mass of the bio-based copolymer nylon composites of each example and each comparative example after immersion was measured. The mass change rate (%) of the bio-based copolymer nylon composites of each example and each comparative example before and after immersion was calculated. The results are shown in Table 3.

[0136] Table 3. Mass change rate of bio-based copolymer nylon composite materials before and after immersion in each example and comparative example.

[0137] project Quality change rate, % Example 1 2.1 Example 2 1.8 Example 3 3.2 Example 4 2.5 Comparative Example 1 12.2 Comparative Example 2 16.8 Comparative Example 3 20.3 Comparative Example 4 11.1 Comparative Example 5 9.9 Comparative Example 6 13.1

[0138] From Table 3 and Figures 5-7 As can be seen from the comparison between Examples 1-4 and Comparative Examples 1-6, the mass change rate of the bio-based copolymer nylon composite materials prepared in Examples 1-4 is lower than that of the bio-based copolymer nylon composite materials prepared in Comparative Examples 1-6. This indicates that the bio-based copolymer nylon composite material provided by the embodiments of the present invention can effectively block the penetration of polar solvents (N,N-dimethylformamide). Therefore, the bio-based copolymer nylon composite material provided by the embodiments of the present invention has excellent solvent resistance.

[0139] 5. Performance testing of bio-based copolymer nylon composites

[0140] The bio-based copolymer nylon composites of Examples 1-4 and Comparative Examples 1-6 were subjected to the following tests, and the test results are shown in Table 4.

[0141] (1) Glass transition temperature (°C): The glass transition temperature was determined using a DSC instrument under a nitrogen atmosphere at a heating rate of 10°C / min.

[0142] (2) Transmittance (%): Transmittance was tested using a UV spectrophotometer;

[0143] (3) Water vapor transmission rate (cc / m 2 (day.atm): Water vapor transmission rate was tested according to standard ASTM F1249-2001;

[0144] (4) Oxygen transmission rate (cc / m 2 .day.atm): Oxygen permeability test was conducted in accordance with standard GB / T19798-2005;

[0145] (5) Relative viscosity: The relative viscosity of the bio-based copolymer nylon composite material with a concentration of 0.5 g / dL was measured using an Ubbelohde viscometer in a concentrated sulfuric acid solution with a temperature of (25±0.01)℃ and a mass fraction of 98%.

[0146] (6) Tensile strength (MPa): Tensile strength test shall be performed in accordance with standard ISO 527-1 / -2;

[0147] (7) Bending strength (MPa): Bending strength test was performed in accordance with standard ISO 178.

[0148] Table 4 Test Results

[0149]

[0150]

[0151] As shown in Table 4, the bio-based copolymer nylon composite material of this invention exhibits excellent transparency (light transmittance up to 91.8%) and barrier properties (water vapor transmittance as low as 15.2 cc / m). 2 The day atm and oxygen permeability are as low as 2.1 cc / m 2 The bio-based copolymer nylon composite material exhibits excellent transparency and barrier properties. Comparative Examples 1 and 1-2 show that when the bio-based cellulose nanofiber contains carboxyl groups, the resulting bio-based copolymer nylon composite material also exhibits excellent transparency, barrier properties, heat resistance, mechanical properties, and toughness. Comparative Examples 1 and 4 show that when the length of the nanofiber is 200 nm, the resulting bio-based copolymer nylon composite material exhibits excellent transparency, barrier properties, heat resistance, mechanical properties, and toughness. Comparing Example 1 and Comparative Example 5, it was found that when the melt extrusion temperature was 265°C, the prepared bio-based copolymer nylon composite material exhibited excellent transparency, barrier properties, heat resistance, mechanical properties, and toughness. The inventors analyzed this and believe the reason may be that a higher melt extrusion temperature can effectively reduce the melt viscosity of the bio-based copolymer nylon resin, thereby improving its fluidity. This helps to improve the dispersion of nanocellulose in the bio-based copolymer nylon resin, allowing for more complete amide exchange between nanocellulose and the bio-based copolymer nylon resin, forming more chemical grafts, promoting interfacial bonding between nanocellulose and the bio-based copolymer nylon resin, and better exerting its reinforcing and modifying effects. This results in a bio-based copolymer nylon composite material with excellent transparency, barrier properties, solvent resistance, heat resistance, mechanical properties, and toughness. Comparing Example 1, Comparative Example 5, and Comparative Example 6, it was found that although the bio-based copolymer nylon composite material in Comparative Example 6 had excellent transparency (light transmittance of 91.5%), its barrier properties (water vapor transmission rate of 115 cc / m³) were not as good. 2 The day atm and oxygen permeability were 7.6 cc / m. 2The original material exhibits poor light transmittance (light transmittance up to 91.8%), heat resistance (glass transition temperature of 62℃), mechanical properties (tensile strength of 65MPa), and toughness (flexural strength of 86MPa). In contrast, the bio-based copolymer nylon composite material prepared in Example 1 of this invention possesses excellent transparency (light transmittance up to 91.8%) and excellent barrier properties (water vapor transmittance as low as 15.2cc / m²). 2 The day atm and oxygen permeability are as low as 2.1 cc / m 2 It has properties such as heat resistance (glass transition temperature up to 109℃), mechanical properties (tensile strength up to 91MPa) and toughness (flexural strength up to 158MPa).

[0152] In summary, the bio-based nylon composite material prepared in the embodiments of the present invention has excellent transparency (light transmittance up to 91.8%), barrier properties, and solvent resistance. It also has excellent heat resistance (glass transition temperature up to 109℃), mechanical properties (tensile strength up to 91MPa), and toughness (flexural strength up to 158MPa). It has broad application prospects in food packaging, medical devices, smart wearable electronics, flexible displays, and other fields.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly transparent and highly barrier bio-based copolymer nylon composite material, characterized in that, The raw materials for preparing the bio-based nylon composite material include bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant, and a first auxiliary agent; the bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 510 or bio-based copolymer nylon resin 5T / 512. The bio-based copolymer nylon resin is 92 to 98 parts, and the nanocellulose is 1 to 5 parts; The length of the nanocellulose is less than 300 nm, and the carboxyl content in the nanocellulose is 1.2 mmol / g to 3.0 mmol / g; The bio-based copolymer nylon composite material is obtained by a preparation method including the following process: mixing and dispersing the bio-based copolymer nylon resin, the nanocellulose, the compatibilizer, the antioxidant and the first auxiliary agent to obtain a mixture, and then performing melt extrusion, traction and granulation on the mixture in a screw extruder to obtain the final product; wherein the melt extrusion temperature is 260℃~280℃.

2. The highly transparent and highly barrier bio-based copolymer nylon composite material according to claim 1, characterized in that, By weight, the raw materials used in the preparation comprise 92 to 98 parts of the bio-based copolymer nylon resin, 1 to 5 parts of the nanocellulose, 1 to 5 parts of the compatibilizer, 0.1 to 0.5 parts of the antioxidant, and 0.1 to 2 parts of the first auxiliary agent.

3. The highly transparent and highly barrier bio-based copolymer nylon composite material according to claim 1, characterized in that, The relative viscosity of the bio-based copolymer nylon resin 5T / 510 is 2.42 to 2.56, and the relative viscosity of the bio-based copolymer nylon resin 5T / 512 is 2.61 to 2.

63.

4. The highly transparent and highly barrier bio-based copolymer nylon composite material according to claim 1, characterized in that, The compatibilizer is at least one of ethylene acrylate copolymer, ethylene-octene copolymer grafted with maleic anhydride, and glycidyl methacrylate grafted with modified polyether block amide copolymer. And / or, the antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 264, antioxidant TNP, and antioxidant TPP; And / or, the first additive includes a lubricant.

5. The highly transparent and highly barrier bio-based copolymer nylon composite material according to claim 1, characterized in that, The preparation process of the bio-based copolymer nylon resin is as follows: A mixed solution of nylon 5T salt was obtained by mixing dicarboxylic acid, terephthalic acid and deionized water and then adding 1,5-pentanediamine for neutralization. The catalyst, end-capping agent, second auxiliary agent and the nylon 5T salt mixed solution are concentrated and prepolymerized to obtain nylon 5T prepolymer; The nylon 5T prepolymer was polymerized under vacuum negative pressure to obtain a bio-based copolymer nylon resin.

6. The highly transparent and highly barrier bio-based copolymer nylon composite material according to claim 5, characterized in that, The dicarboxylic acid is sebacic acid or dodecanoic acid; When the dicarboxylic acid is sebacic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 510. When the dicarboxylic acid is dodecanoic acid, the prepared bio-based copolymer nylon resin is bio-based copolymer nylon resin 5T / 512.

7. A method for preparing a highly transparent and highly barrier bio-based copolymer nylon composite material according to any one of claims 1 to 6, characterized in that, include: Preparation of bio-based copolymer nylon resin; Preparation of bio-based copolymer nylon composite materials: The bio-based copolymer nylon resin, nanocellulose, compatibilizer, antioxidant and first auxiliary agent are mixed and dispersed to obtain a mixture. The mixture is then melt-extruded, drawn and granulated in a screw extruder to obtain a bio-based copolymer nylon composite material.

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