Nylon modified material as well as preparation method and application thereof

Abstract

The invention provides a nylon modified material as well as a preparation method and application thereof, and relates to the technical field of nylon compositing, the nylon modified material comprises the following components: nylon 66, low-viscosity nylon 6, a toughening agent, a compatilizer and a flow crystallization accelerant; wherein the toughening agent comprises a block copolymer containing a polyethylene glycol chain segment and a polydimethylsiloxane chain segment; the compatilizer comprises a compound containing a diglycidyl ether group. According to the nylon modified material provided by the invention, under the condition that the modulus of nylon 66 is slightly reduced, the impact strength is improved, so that the nylon modified material has the characteristics of high flowability, high toughness, self-lubrication and the like, and can meet the requirements of occasions such as automobile parts and industrial production.

Description

Technical Field

[0001] This invention relates to the field of nylon composite materials technology, and in particular to a modified nylon material, its preparation method, and its application. Background Technology

[0002] Polyamide (PA), commonly known as nylon, is a general term for a class of high molecular weight polymers containing amide groups in their main molecular chain. There are two main structures: one is formed by the ring-opening polymerization of lactams or the self-condensation polymerization of amino acids; the other is formed by the condensation polymerization of organic diacids and diamines. Based on the specific groups contained in the molecular chain, they can be divided into four types: aliphatic, semi-aromatic, aromatic, and copolymer polyamides. PA66 is the most typical aliphatic polyamide, an engineering plastic with excellent mechanical properties, heat resistance, and chemical resistance, widely used in automotive, machinery, and other industrial fields.

[0003] However, PA66 has poor toughness and is sensitive to notches, especially exhibiting low impact strength at low temperatures and in a dry state. Traditional toughening modification methods involve blending PA66 with rubber and thermoplastic elastomers, but the incompatibility between the two phases results in minimal improvement in impact strength. Therefore, further improvements have been proposed, such as functionalizing the rubber and thermoplastic elastomers. A common method is grafting maleic anhydride (MAH) onto the rubber and thermoplastic elastomer. During extrusion, MAH reacts with the amino or amide groups at the ends of nylon 66 to form an in-situ copolymer, enhancing the compatibility between the toughening agent and PA66. While this method effectively improves the toughness of PA66, it also leads to a decrease in its modulus and strength, as well as a significant reduction in flowability, which is detrimental to subsequent molding and processing.

[0004] Chinese invention patent CN101591470B discloses a filled and toughened PA66 composite material and its preparation method, which uses a core-shell polymer MBS for toughening, but the toughening effect is poor, with a notched impact strength of only 8 kJ / m. 2 It falls far short of achieving high toughness. Chinese invention patent CN104250441B discloses a flame-retardant toughening agent for PA66 and a flame-retardant toughened PA66 material prepared from it. The toughening agent used is carbon nanotube-copper composite powder. This toughening agent is expensive and difficult to produce. Although the notched impact strength reaches 16 kJ / m... 2However, its flowability was not studied. Chinese invention patent CN104371316B discloses a ternary nanocomposite material of nylon 66 / POE-g-MAH / titanium dioxide and its preparation method. It utilizes titanium dioxide and POE-g-MAH to synergistically toughen PA66. While impact strength increases, tensile strength decreases significantly. Furthermore, its flowability was not considered, which is detrimental to subsequent processing and production. Chinese invention patent CN104610505B discloses a nylon toughening agent with high toughening efficiency and high flowability and its preparation method. It utilizes inorganic rigid particles and POE-g-MAH to obtain a nylon toughening agent with high toughening efficiency and high flowability. While flowability is improved, tensile strength, flexural strength, and flexural modulus decrease significantly, with the flexural modulus only around 1500 MPa, greatly limiting its application.

[0005] In summary, the toughened PA66 unbleached materials currently in use on the market typically cannot simultaneously achieve good modulus, toughness, and flowability.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] One of the objectives of this invention is to provide a modified nylon material to at least solve one of the technical problems existing in the prior art.

[0008] The second objective of this invention is to provide a method for preparing modified nylon materials.

[0009] A third objective of this invention is to provide an application of a modified nylon material or a modified nylon material prepared by the aforementioned preparation method in the manufacture of automotive parts.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a nylon modified material comprising the following components: nylon 66, low-viscosity nylon 6, toughening agent, compatibilizer, and flow crystallization promoter; The toughening agent comprises a block copolymer containing polyethylene glycol segments and polydimethylsiloxane segments; the compatibilizer comprises a compound containing diglycidyl ether groups.

[0011] Furthermore, it includes the following components in parts by mass: 65-80 parts nylon 66, 10-20 parts low viscosity nylon 6, 6-14 parts toughening agent, 0.2-1.5 parts compatibilizer and 2-4 parts flow crystallization promoter; Preferably, the components of the nylon modified material further include: antioxidants and nucleating agents; Preferably, the nylon modified material further comprises, by weight parts: 0.3-0.6 parts of antioxidant and 0.03-0.1 parts of nucleating agent; Preferably, the antioxidants include hindered phenolic compounds, phosphite compounds, and phosphorus-containing inorganic salt compounds; Preferably, the nucleating agent includes one or more of talc, mica, barium sulfate, and magnesium hydroxide; Preferably, the talc powder has a particle size of 0.3~1 μm, and the talc powder has an ablation rate of ≤6.0% at 1050℃.

[0012] Furthermore, the characteristic viscosity of the nylon 66 is 2.6~3.0 Pa·s; Preferably, the nylon 66 comprises powdered nylon 66 and / or granular nylon 66; Preferably, the nylon 66 has a melt mass flow rate of 35~50 g / 10 min under the conditions of a load of 2.16 kg and a test temperature of 275°C.

[0013] Furthermore, the characteristic viscosity of the low-viscosity nylon 6 is 2.0~2.2 Pa·s; Preferably, the low-viscosity nylon 6 comprises granular low-viscosity nylon 6 or powdered low-viscosity nylon 6; Preferably, the low-viscosity nylon 6 has a melt flow rate of 25~35 g / 10 min under the conditions of a load of 0.325 kg and a test temperature of 250°C.

[0014] Furthermore, the toughening agent includes polyethylene glycol-polydimethylsiloxane block copolymer and / or polyethylene glycol-polydimethylsiloxane-polyethylene glycol triblock copolymer; Preferably, the toughening agent has a number-average molecular weight of 25,000 to 40,000 g / mol; Preferably, the toughening agent has a molecular weight distribution ≤1.3; Preferably, the number-average molecular weight of the polyethylene glycol-polydimethylsiloxane block copolymer is 26,000-30,000 g / mol.

[0015] Furthermore, the compatibilizer is one or more of polyethylene glycol diglycidyl ether, aliphatic diglycidyl ether, and cyclic diglycidyl ether; Preferably, the number-average molecular weight of the compatibilizer is 200-1000 g / mol.

[0016] Furthermore, the flow crystallization promoter includes glycerol and / or sorbitan monostearate.

[0017] Secondly, the present invention provides a method for preparing a nylon modified material, comprising the following steps: (a) Nylon 66 and flow crystallization promoter are mixed, and then compatibilizer, antioxidant and nucleating agent are added to obtain Nylon 66 mixture; (b) Nylon 66 mixture, low viscosity nylon 6 and toughening agent are placed in separate raw material bins, and after melt blending, extrusion and pelletizing, nylon modified material is obtained.

[0018] Furthermore, a twin-screw extruder is used for the melt blending and the extrusion. Preferably, the twin-screw extruder includes a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone, a seventh temperature zone, an eighth temperature zone, a ninth temperature zone, and a die head; Preferably, the temperature of the first temperature zone is 220±5℃; the temperature of the second temperature zone is 240±5℃; the temperature of the third temperature zone is 260±5℃; the temperature of the fourth temperature zone is 270±5℃; the temperature of the fifth temperature zone is 270±5℃; the temperature of the sixth temperature zone is 265±5℃; the temperature of the seventh temperature zone is 265±5℃; the temperature of the eighth temperature zone is 265±5℃; the temperature of the ninth temperature zone is 265±5℃; and the die head temperature of the twin-screw extruder is 270±5℃.

[0019] Thirdly, the present invention provides an application of a modified nylon material or a modified nylon material prepared by the aforementioned preparation method in the preparation of automotive parts.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The nylon modified material provided by this invention uses nylon 66 (PA66) as the main matrix, ensuring strength and modulus while incorporating low-viscosity nylon 6, which is low-cost and has good flowability, to improve its flowability and reduce costs. In this invention, the toughening agent includes a block copolymer containing polyethylene glycol segments and polydimethylsiloxane segments. The polyethylene glycol segments (PEG segments) have good polarity and flexibility, effectively weakening the hydrogen bonding forces between nylon 66 molecules, reducing the internal friction of the system, thereby significantly improving the melt flowability of the material and enhancing its processing performance. The PEG segment also has a certain internal lubricating effect, which helps to reduce the surface friction coefficient of the material and endow the material with certain self-lubricating properties. The polydimethylsiloxane segment (PDMS segment) has extremely high flexibility and rotational freedom because the main chain is composed of alternating silicon (Si) and oxygen (O) atoms. Therefore, the glass transition temperature (Tg) is extremely low (about -120℃). It can maintain high elasticity in the range of -50℃ to 200℃. Therefore, PDMS is suitable as an elastomer toughening material. In addition, PDMS has a low surface energy, which can play a certain lubricating role. The compatibilizer containing diglycidyl ether groups works synergistically with the plasticizer to significantly improve the interfacial compatibility between material components. The flow crystallization promoter used in this invention can not only effectively reduce the melt viscosity of the nylon 66 system and improve processing fluidity, but also significantly increase the crystallization rate and shorten the cooling and setting time. At the same time, the flow crystallization promoter, in synergy with the toughening agent, helps to form a fine and uniform grain structure, thereby improving the toughness of the material without significantly increasing the final crystallinity, achieving an organic unity of high fluidity, high toughness and high processing efficiency.

[0021] The nylon modified material provided by this invention improves the impact strength of nylon 66 while slightly reducing its modulus, and gives it the characteristics of high fluidity, high toughness, and self-lubrication, which can meet the needs of automotive parts, industrial production and other applications. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the preparation process of the nylon modified material provided by the present invention; Figure 2 The crystallization curves of the examples and comparative samples obtained by DSC testing are shown. Detailed Implementation

[0024] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Because the toughened PA66 natural color modified materials currently used in the market have problems such as poor flowability and easy yellowing, the traditional method is to use maleic anhydride modified thermoplastic elastomers to toughen PA66, but this will lead to a significant decrease in its flowability, which is not conducive to subsequent production.

[0027] In view of this, the first aspect of the present invention provides a nylon modified material comprising the following components: nylon 66, low viscosity nylon 6, toughening agent, compatibilizer and flow crystallization promoter; The toughening agent comprises a block copolymer containing polyethylene glycol segments and polydimethylsiloxane segments; the compatibilizer comprises a compound containing diglycidyl ether groups.

[0028] The nylon modified material provided by this invention is a high-flowability, high-toughness and self-lubricating nylon modified material. It significantly improves the impact strength of nylon 66 while slightly reducing its modulus, without affecting the flowability and whiteness of nylon 66, thus giving it the characteristics of high flowability, high toughness and self-lubrication.

[0029] In some preferred embodiments, the nylon modified material comprises the following components in parts by weight: 63-80 parts Nylon 66, 10-20 parts low-viscosity Nylon 6, 6-14 parts toughening agent, 0.2-1 part compatibilizer and 2-4 parts flow crystallization promoter.

[0030] In the nylon modified material, the amount of nylon 66 added is 63 to 80 parts, for example, 63 parts, 65 parts, 70 parts, 75 parts, 80 parts, etc. In the nylon modified material, the amount of low-viscosity nylon 6 added is 10 to 20 parts, for example, it can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc. In the modified nylon material, the amount of toughening agent added is 6 to 14 parts, for example, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, etc. In the nylon modified material, the amount of compatibilizer added is 0.2 to 1.5 parts, for example, it can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, etc.; In the modified nylon material, the amount of flow crystallization promoter added is 2 to 4 parts, for example, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc.

[0031] Preferably, the components of the nylon modified material further include: antioxidants and nucleating agents; Preferably, the nylon modified material further comprises, by weight parts: 0.3-0.6 parts of antioxidant and 0.03-0.1 parts of nucleating agent; The amount of antioxidant added in the nylon modified material is 0.3 to 0.6 parts, for example, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc. In the modified nylon material, the amount of nucleating agent added is 0.03 to 0.1 parts, for example, it can be 0.03 parts, 0.04 parts, 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, etc.

[0032] Preferably, the antioxidants include hindered phenolic compounds, phosphite compounds, and phosphorus-containing inorganic salt compounds; The antioxidant is preferably one or a combination of N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (i.e., antioxidant 1098), tris(2,4-di-tert-butylphenyl) phosphite (i.e., antioxidant 168), and phosphorus-containing inorganic salt antioxidant stabilizer (H10); antioxidant stabilizer H10 can stabilize color and has antioxidant effect; the antioxidant in this invention is preferably a composite antioxidant, in which the ratio of 1098, 168 and H10 is 1:1:1.

[0033] Preferably, the nucleating agent includes one or more of talc, mica, barium sulfate, and magnesium hydroxide; Preferably, the talc powder has a particle size of 0.3~1 μm, and the talc powder has an ablation rate of ≤6.0% at 1050℃.

[0034] In some preferred embodiments, the characteristic viscosity of the nylon 66 is 2.6~3.0 Pa·s, for example, it can be 2.6 Pa·s, 2.7 Pa·s, 2.8 Pa·s, 2.9 Pa·s, 3.0 Pa·s, etc.; Preferably, the nylon 66 comprises powdered nylon 66 and / or granular nylon 66; Preferably, the nylon 66 has a melt mass flow rate of 35~50 g / 10 min under the conditions of a load of 2.16 kg and a test temperature of 275°C.

[0035] In some preferred embodiments, the characteristic viscosity of the low-viscosity nylon 6 is 2.0~2.2 Pa·s, for example, it can be 2.0 Pa·s, 2.1 Pa·s, 2.2 Pa·s, etc. Preferably, the low-viscosity nylon 6 comprises granular low-viscosity nylon 6 or powdered low-viscosity nylon 6; Preferably, the low-viscosity nylon 6 has a melt flow rate of 25~35 g / 10 min under the conditions of a load of 0.325 kg and a test temperature of 250°C.

[0036] In some preferred embodiments, the toughening agent comprises polyethylene glycol-polydimethylsiloxane block copolymer (PEG-b-PDMS) and / or polyethylene glycol-polydimethylsiloxane-polyethylene glycol triblock copolymer; PEG-b-PDMS is preferred. Preferably, the toughening agent has a number-average molecular weight of 25,000 to 40,000 g / mol; Preferably, the toughening agent is a powder with a molecular weight distribution ≤1.3; Preferably, the number-average molecular weight of the polyethylene glycol-polydimethylsiloxane block copolymer is 26,000-30,000 g / mol.

[0037] In some preferred embodiments, the compatibilizer is one or more of polyethylene glycol diglycidyl ether, aliphatic diglycidyl ether, and cyclic diglycidyl ether; polyethylene glycol diglycidyl ether is preferred, with a molecular weight Mn of 500 g / mol; Preferably, the number-average molecular weight of the compatibilizer is 200-1000 g / mol.

[0038] In some preferred embodiments, the flow crystallization promoter comprises glycerol and / or sorbitan monostearate, with glycerol (GL) being preferred.

[0039] A second aspect of the present invention provides a method for preparing a nylon modified material, comprising the following steps: (a) Nylon 66 and flow crystallization promoter are mixed, and then compatibilizer, antioxidant and nucleating agent are added to obtain Nylon 66 mixture; (b) Nylon 66 mixture, low viscosity nylon 6 and toughening agent are placed in separate raw material bins, and after melt blending, extrusion and pelletizing, nylon modified material is obtained.

[0040] In some preferred embodiments, a twin-screw extruder is used for the melt blending and the extrusion. Preferably, the twin-screw extruder includes a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone, a seventh temperature zone, an eighth temperature zone, a ninth temperature zone, and a die head; Preferably, the temperature of the first temperature zone (hereinafter referred to as: zone 1 temperature) is 220±5℃; the temperature of the second temperature zone (hereinafter referred to as: zone 2 temperature) is 240±5℃; the temperature of the third temperature zone (hereinafter referred to as: zone 3 temperature) is 260±5℃; the temperature of the fourth temperature zone (hereinafter referred to as: zone 4 temperature) is 270±5℃; the temperature of the fifth temperature zone (hereinafter referred to as: zone 5 temperature) is 270±5℃; the temperature of the sixth temperature zone (hereinafter referred to as: zone 6 temperature) is 265±5℃; the temperature of the seventh temperature zone (hereinafter referred to as: zone 7 temperature) is 265±5℃; the temperature of the eighth temperature zone (hereinafter referred to as: zone 8 temperature) is 265±5℃; the temperature of the ninth temperature zone (hereinafter referred to as: zone 9 temperature) is 265±5℃; and the die head temperature of the twin-screw extruder is 270±5℃.

[0041] In this invention, to achieve good melting, uniform mixing, and stable extrusion of the components, a twin-screw extrusion process with temperature gradient control is employed. Specifically, the feeding zones (zones 1 and 2) have a lower temperature to prevent material bridging, and the temperature is gradually increased to the melting zone. The mixing zone maintains a stable temperature to facilitate shear dispersion, and the die head temperature is slightly higher to ensure smooth melt extrusion.

[0042] Among the optional embodiments of the present invention, the more preferred one is as follows: Figure 1 As shown, the preparation method of the nylon modified material includes the following steps: (1) Raw material drying: Nylon 66 powder and Nylon 6 granules were vacuum dried at 80°C for 24 hours and then placed in aluminum foil bags and sealed for later use; (2) Mixing Nylon 66 powder with additives: Add Nylon 66 powder and flow crystallization promoter to a high-speed mixer and stir at a low speed of less than 500 rpm for more than 5 minutes. Start the high-speed mixer and stir at a speed of more than 1000 rpm for more than 5 minutes. After cooling for 5 minutes, add compatibilizer, composite antioxidant and nucleating agent and start the high-speed mixer at a speed of more than 1000 rpm for more than 5 minutes. Then discharge the material to the raw material silo to obtain Nylon 66 mixture; low viscosity Nylon 6 and toughening agent are added to the other two raw material silos respectively. (3) Twin-screw blending modified extrusion granulation: Add all the raw materials from the above raw material bins into the twin-screw extruder, and after the screw shears, mixes and disperses evenly, it is extruded from the extruder head, cooled by water tank, dried by air blowing, and granulated by pelletizer to obtain high-flowability and high-toughness plasticized nylon 66 modified material.

[0043] The nylon modified material provided by this invention uses PEG-b-PDMS, which has a self-lubricating effect, as a toughening agent. The presence of PEG segments weakens the intermolecular forces of nylon 66, thereby achieving a lubricating effect and significantly improving fluidity. PDMS, due to its main chain composed of alternating silicon (Si) and oxygen (O) atoms, has extremely high flexibility and rotational freedom, resulting in a very low glass transition temperature (Tg) (approximately -120°C). It maintains high elasticity within the range of -50°C to 200°C, making PDMS suitable as an elastomer toughening material. Furthermore, PDMS has a low surface energy, which also contributes to lubrication. However, PDMS itself has weak polarity and is not well compatible with polar PA66. Therefore, PEG segments are introduced for modification, and low-molecular-weight PEG-DGE is added as a compatibilizer to synergistically enhance its compatibility with PA66, forming elastic particles that toughen PA66 and improve its impact performance at low and room temperatures. In addition, PDMS has excellent flame retardant properties. When burning, it forms a silicon dioxide (SiO2) char layer, in which the SiO2 char covers the surface of the material, playing a role in heat insulation and oxygen isolation, and inhibiting the spread of flame.

[0044] This invention creatively proposes a flow crystallization promoter for toughened nylon 66 systems. In existing toughened PA66 systems, it is often necessary to inhibit PA66 crystallization, reduce its crystallinity, and further improve impact strength. However, this invention selects GL as the flow crystallization promoter, which can weaken the intermolecular forces of nylon 66, thereby achieving a lubricating effect and significantly improving flowability. Simultaneously, it works synergistically with the nucleating agent talc to reduce the grain size of nylon 66, changing its crystal form, allowing it to crystallize at higher temperatures, forming small spherulites and maintaining a certain degree of crystallinity, thus ensuring the mechanical strength of nylon 66. Furthermore, GL is more dispersed in the amorphous region, and the presence of hydroxyl groups on the GL surface allows it to synergistically interact with PEG-b-PDMS, significantly improving the toughness of PA66 while essentially not reducing (or slightly reducing) the modulus.

[0045] The nylon modified material prepared by the method provided in this invention significantly improves impact strength, flowability, and processing performance while maintaining its modulus, and also enhances the self-lubricating and flame-retardant properties of nylon 66. Furthermore, this material is characterized by low cost and simple preparation and application methods. It can be processed and molded using conventional high-speed mixers and twin-screw extruders.

[0046] A third aspect of the present invention provides the application of a modified nylon material or a modified nylon material prepared by the aforementioned preparation method in the manufacture of automotive parts, particularly in automotive rearview mirror bases.

[0047] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0048] The raw materials used in the following examples and comparative examples: The toughening agent selected is PEG-b-PDMS with a strength of 1.6-b-30.0 and a concentration of 28000 g / mol; The compatibilizer selected is polyethylene glycol diglycidyl ether (PEG-DGE), with a molecular weight Mn of 500 g / mol; Talc powder with a particle size of 0.3~1 μm and an ablation rate of ≤6.0% at 1050℃.

[0049] Example 1 This embodiment provides a modified nylon material, the components of which, by mass parts, include: 73.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 8 parts PEG-b-PDMS powder, 2 parts GL liquid, 0.5 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc.

[0050] The preparation process of the nylon modified material is as follows: (1) The PA66 powder and low-viscosity PA6 granules were placed in a vacuum drying oven at 80℃ for 24 h for drying. (2) Then, GL and PA66 powder were mixed in a high-speed mixer and stirred at 450 rpm for 10 min to form preplasticized PA66. After cooling for 5 min, PEG-DGE, antioxidant 1098, antioxidant 168, antioxidant stabilizer H10 and talc were added to the high-speed mixer for thorough mixing. The mixture was stirred at 1500 rpm for 10 min to obtain preplasticized PA66 mixture. Then, the preplasticized PA66 mixture, low viscosity PA6 granules and PEG-b-PDMS were discharged into three raw material bins respectively. (3) Twin-screw blending modified extrusion granulation: Add all the raw materials from the above raw material bins into the twin-screw extruder, and control the temperature of the twin-screw extruder as follows: Zone 1 temperature 220℃, Zone 2 temperature 240℃, Zone 3 temperature 260℃, Zone 4 temperature 270℃, Zone 5 temperature 270℃, Zone 6 temperature 265℃, Zone 7 temperature 265℃, Zone 8 temperature 265℃, Zone 9 temperature 265℃, and die head temperature 270℃; after the modified and toughened PA66 melt is extruded from the die head of the extruder, it is cooled in a water tank, dried by blowing air, granulated by a pelletizer, and screened by a vibrating screen to obtain the modified nylon material.

[0051] Example 2 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 71.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 8 parts PEG-b-PDMS powder, 4 parts GL liquid, 0.5 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0052] Example 3 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 77.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 4 parts PEG-b-PDMS powder, 2 parts GL liquid, 0.5 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0053] Example 4 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 69.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 12 parts PEG-b-PDMS powder, 2 parts GL liquid, 0.5 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0054] Example 5 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 74 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 8 parts PEG-b-PDMS powder, 2 parts GL liquid, 1 part PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0055] Example 6 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 63 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 20 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 14 parts PEG-b-PDMS powder, 3 parts GL liquid, 0.2 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0056] Example 7 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By weight, its components include: 80 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 10 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 6 parts PEG-b-PDMS powder, 2 parts GL liquid, 1.5 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0057] Example 8 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 75.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 5 parts PEG-b-PDMS powder, 2 parts GL liquid, 2 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0058] Example 9 This embodiment provides a modified nylon material, which differs from Embodiment 1 in that: By mass, its components include: 67.9 parts PA66 powder (characteristic viscosity: 2.8 Pa·s), 15 parts low-viscosity PA6 granules (characteristic viscosity: 2.0 Pa·s), 15 parts PEG-b-PDMS powder, 2 parts GL liquid, 0.1 parts PEG-DGE, 0.2 parts antioxidant 1098, 0.2 parts antioxidant 168, 0.2 parts antioxidant stabilizer H10, and 0.05 parts talc. Its preparation method is the same as that in Example 1.

[0059] Comparative Example 1 This comparative example provides a nylon material that differs from Example 1 in that, by mass parts, its components include: 99.6 parts of PA66 granules (characteristic viscosity: 2.8 Pa·s), 0.2 parts of antioxidant 1098, and 0.2 parts of antioxidant 168; The preparation process is as follows: First, PA66 granules are thoroughly mixed with antioxidant 1098 and antioxidant 168 in a high-speed mixer. The mixture is stirred for 10 minutes at a stirring speed of 1500 rpm and then discharged into the raw material silo. After the PA66 melt is extruded from the extruder head, it is cooled in a water tank, dried by a blower, granulated by a pelletizer, and screened by a vibrating screen to obtain nylon 66 material. The temperature of each zone of the twin-screw extruder is the same as in Example 1.

[0060] Comparative Example 2 This comparative example provides a nylon material that differs from Example 1 in that, by mass parts, its components include: 91.2 parts of PA66 granules (characteristic viscosity: 2.8 Pa·s), 8 parts of POE-g-MAH (MAH grafting rate: 0.6%) granules, 0.4 parts of calcium stearate, 0.2 parts of antioxidant 1098, and 0.2 parts of antioxidant 168; The preparation process is as follows: First, PA66 granules are placed in a vacuum drying oven at 80℃ for 24 hours for drying. After drying, PA66 granules are mixed with calcium stearate, antioxidant 1098, antioxidant 168, and POE-g-MAH in a high-speed mixer to obtain PA66 mixture. Then, the mixture is discharged into the raw material silo. The modified and toughened PA66 melt is extruded from the extruder head, cooled in a water tank, dried by air, pelletized by a pelletizer, and screened by a vibrating screen to obtain nylon material. The mixing rate, time, and temperature of each zone of the twin-screw extruder are the same as in Example 1.

[0061] Comparative Example 3 This comparative example provides a nylon material that differs from Example 4 in that it does not contain PEG-DGE and contains 70.4 parts of PA66 powder.

[0062] Test Example 1 Test samples: The nylon modified materials prepared in Examples 1-9 and the nylon materials prepared in Comparative Examples 1-3 were used as samples for testing.

[0063] Test method: The melt mass flow rate (MFR) was tested according to GB / T 3682-2018, with a load of 2.16 kg and a temperature of 275℃. Tensile properties were tested according to GB / T 1040-2022 (to obtain tensile strength and elongation at break), and the test speed was 5 mm / min; Bending performance was tested according to GB / T 9341-2008 at a test speed of 2 mm / min. Impact performance was tested according to GB / T 1043-2018, and the test was a notched impact test on a simply supported beam.

[0064] The test results are shown in Table 1.

[0065] Table 1

[0066] As shown in Table 1, the high-flowability, high-toughness, and self-lubricating nylon modified material provided by this invention exhibits excellent comprehensive performance within the preferred embodiment range (Examples 1-9). Among them, Example 4 achieves the best balance in toughening effect, flowability, and mechanical properties, with a notched impact strength of up to 28.34 kJ / m². 2 It significantly outperforms the notched impact strength of simply supported beams of the materials in Comparative Examples 1-3, while maintaining a melt mass flow rate (MFR) of 27.3 g / 10 min, exhibiting good processing fluidity; the tensile strength is 53.9 MPa and the flexural modulus is 2010 MPa. Although the flexural modulus is not as high as that of the pure PA66 material in Comparative Example 1, it is still at an excellent level in the high toughening system, meeting the design goal of "slightly reducing the modulus to significantly improve toughness".

[0067] In contrast, Examples 8 and 9 showed decreased performance due to the amount of compatibilizer or toughening agent exceeding the preferred range: the impact strength of Example 8 decreased to 12.29 kJ / m due to uneven dispersion caused by excessive PEG-DGE. 2 Example 9: Due to excessive toughening agent, compatibility deteriorated, although the impact strength reached 23.5 kJ / m. 2 However, it is still lower than that of Example 4, and the color value b increases to 4.6, indicating an increased tendency to yellow. In addition, the color L value of all examples is higher than 80, the a value is relatively negative, and the b value is low, indicating that the material has good whiteness and no obvious color change has been introduced due to modification.

[0068] Test Example 2 DSC (Differential Scanning Calorimetry) tests were performed on some of the embodiments and comparative examples.

[0069] Differential scanning calorimetry (DSC) was performed according to GB / T 19466-2004, at 30~300℃; 10℃ / min; nitrogen atmosphere.

[0070] Figure 2 The DSC curves show that the crystallization peak temperature (Tc) of Examples 1, 3, and 4 is relatively high, indicating a faster crystallization rate. It is evident that the addition of flow crystallization promoters (such as glycerol, GL) and nucleating agents (such as talc) can promote the crystallization behavior of nylon 66 during cooling and increase the crystallization temperature. This helps the material crystallize faster during processing, shortens the cooling and setting time, and improves processing efficiency. In contrast, Comparative Example 1 has a lower crystallization temperature and a wider crystallization peak, indicating a slower crystallization rate.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 modified nylon material, characterized in that, It includes the following components: Nylon 66, low viscosity Nylon 6, toughening agent, compatibilizer and flow crystallization promoter; The toughening agent comprises a block copolymer containing polyethylene glycol segments and polydimethylsiloxane segments; the compatibilizer comprises a compound containing diglycidyl ether groups.

2. The nylon modified material according to claim 1, characterized in that, It includes the following components by mass parts: 63-80 parts of nylon 66, 10-20 parts of low-viscosity nylon 6, 6-14 parts of toughening agent, 0.2-1.5 parts of compatibilizer and 2-4 parts of flow crystallization promoter; The components of the modified nylon material also include: antioxidants and nucleating agents; The nylon modified material further comprises, by weight parts: 0.3-0.6 parts antioxidant and 0.03-0.1 parts nucleating agent; Antioxidants include hindered phenolic compounds, phosphite compounds, and phosphorus-containing inorganic salt compounds; The nucleating agent includes one or more of talc, mica, barium sulfate, and magnesium hydroxide; The talc powder has a particle size of 0.3~1 μm, and the talc powder has an ablation rate of ≤6.0% at 1050℃.

3. The nylon modified material according to claim 1, characterized in that, The characteristic viscosity of the nylon 66 is 2.6~3.0 Pa·s; The nylon 66 includes powdered nylon 66 and / or granular nylon 66; The nylon 66 exhibits a melt flow rate of 35~50 g / 10 min under a load of 2.16 kg and a test temperature of 275℃.

4. The nylon modified material according to claim 1, characterized in that, The characteristic viscosity of the low-viscosity nylon 6 is 2.0~2.2 Pa·s; The low-viscosity nylon 6 includes granular low-viscosity nylon 6 or powdered low-viscosity nylon 6; The low-viscosity nylon 6 exhibits a melt flow rate of 25~35 g / 10 min under conditions of a load of 0.325 kg and a test temperature of 250 °C.

5. The nylon modified material according to claim 1, characterized in that, The toughening agent includes polyethylene glycol-polydimethylsiloxane block copolymer and / or polyethylene glycol-polydimethylsiloxane-polyethylene glycol triblock copolymer; The toughening agent has a number-average molecular weight of 25,000 to 40,000 g / mol; The toughening agent has a molecular weight distribution ≤1.3; The number-average molecular weight of the polyethylene glycol-polydimethylsiloxane block copolymer is 26,000-30,000 g / mol.

6. The nylon modified material according to claim 1, characterized in that, The compatibilizer is one or more of polyethylene glycol diglycidyl ether, aliphatic diglycidyl ether, and cyclic diglycidyl ether; The number-average molecular weight of the compatibilizer is 200-1000 g / mol.

7. The nylon modified material according to claim 1, characterized in that, The flow crystallization promoter includes glycerol and / or sorbitan monostearate.

8. The method for preparing the nylon modified material according to any one of claims 1-7, characterized in that, Includes the following steps: (a) Nylon 66 and flow crystallization promoter are mixed, and then compatibilizer, antioxidant and nucleating agent are added to obtain Nylon 66 mixture; (b) Nylon 66 mixture, low viscosity nylon 6 and toughening agent are placed in separate raw material bins, and after melt blending, extrusion and pelletizing, nylon modified material is obtained.

9. The preparation method according to claim 8, characterized in that, The melt blending and extrusion are performed using a twin-screw extruder; The twin-screw extruder includes a first temperature zone, a second temperature zone, a third temperature zone, a fourth temperature zone, a fifth temperature zone, a sixth temperature zone, a seventh temperature zone, an eighth temperature zone, a ninth temperature zone, and a die head; the temperature of the first temperature zone is 220±5℃; the temperature of the second temperature zone is 240±5℃; the temperature of the third temperature zone is 260±5℃; the temperature of the fourth temperature zone is 270±5℃; the temperature of the fifth temperature zone is 270±5℃; the temperature of the sixth temperature zone is 265±5℃; the temperature of the seventh temperature zone is 265±5℃; the temperature of the eighth temperature zone is 265±5℃; the temperature of the ninth temperature zone is 265±5℃; and the die head temperature of the twin-screw extruder is 270±5℃.

10. The application of the nylon modified material as described in any one of claims 1-7 or the nylon modified material prepared by the preparation method described in claim 8 or 9 in the preparation of automotive parts.

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