A polyamide composition, its preparation method and application

Abstract

This invention relates to a polyamide composition, its preparation method, and its application. The polyamide composition comprises the following components: PA56 resin, glass fiber, and a composite nucleating agent. This invention uses PA56 resin as the main resin, while simultaneously adding glass fiber, an amide nucleating agent, and talc as composite nucleating agents. The resulting polyamide composition not only has a high crystallization temperature and low demolding force, but also good weld line strength.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a polyamide composition, its preparation method, and its application. Background Technology

[0002] Under the dual-carbon strategy, energy conservation and emission reduction have become a trend in automotive development, and reducing the carbon emissions of materials used is a crucial step. Bio-based nylons, whose synthetic monomers are partially or entirely derived from nature, possess inherent advantages in carbon reduction, with emissions only about 50% of those of petroleum-based nylons. Among these, PA56, a type of bio-based nylon, is receiving increasing attention from OEMs due to its carbon reduction and cost advantages, leading to a growing demand for and development of PA56 materials.

[0003] PA56, polymerized from pentanediamine and adipic acid, possesses excellent mechanical properties, hygroscopic properties, thermal stability, flame retardancy, dyeability, abrasion resistance, and flexibility. However, due to its unique structure, low crystallization temperature, and low crystallinity, PA56 exhibits long molding cycles and high demolding forces, limiting its application in large automotive parts. Furthermore, to meet the mechanical property requirements of automotive applications, glass fibers are typically added, but these further reduce the crystallinity of PA56.

[0004] Furthermore, automotive components such as engine cylinder heads typically form weld lines during injection molding. Therefore, the weld line strength of PA56 materials used in the automotive industry also needs to be considered. While the addition of glass fiber increases the strength of PA56 material itself, it can worsen the bonding at the weld line locations, thus degrading the weld line strength. Summary of the Invention

[0005] The primary objective of this invention is to overcome the problems of long molding cycles and high demolding forces in current PA56 materials, and to provide a polyamide composition.

[0006] A further object of the present invention is to provide a method for preparing the above-described polyamide composition.

[0007] A further object of the present invention is to provide the application of the above-described polyamide composition in the preparation of automotive parts.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution:

[0009] A polyamide composition comprising the following components in parts by weight:

[0010] 39-90 parts of PA56 resin

[0011] 9-51 parts glass fiber

[0012] 1-3 parts of composite nucleating agent;

[0013] The composite nucleating agent comprises an amide nucleating agent and talc in a mass ratio of (1.5–4.5):1.

[0014] In this invention, the addition of glass fiber enhances the basic mechanical strength of the polyamide composition.

[0015] The inventors of this invention have discovered that in polyamide composition systems with added glass fibers, due to the inherent "defects" in the molecular structure of PA56 resin and the steric hindrance effect brought by glass fibers, the addition of conventional nucleating agents cannot effectively increase the crystallization temperature and crystallinity of the polyamide composition, especially the crystallinity, thus making it difficult to improve the problem of high demolding force of the polyamide composition.

[0016] The inventors of this invention discovered through research that both amide nucleating agents and talc have a certain nucleating effect. By further utilizing the compatibility of the amide nucleating agent and the overlapping effect brought about by the lamellar structure of talc, not only can the crystallization temperature of the polyamide composition be effectively increased, thus shortening the molding cycle, but the crystallinity of the polyamide composition can also be effectively increased, thus reducing the release force. The absence of either the amide nucleating agent or talc, or the replacement of one with another conventional nucleating agent, cannot simultaneously increase the crystallization temperature and crystallinity of the polyamide composition.

[0017] Furthermore, the inventors have discovered that in the polyamide composition system of the present invention, the crystallization behavior of the material during injection molding is affected by the synergistic effect of amide nucleating agents and talc, thereby effectively improving the weld line strength of the material.

[0018] In this invention, the amount of PA56 resin added can be 39, 40, 45, 48, 50, 52, 55, 58, 60, 65, 68, 70, 75, 78, 80, 85, 88 or 90 parts by weight; the amount of glass fiber added can be 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50 or 51 parts by weight.

[0019] In this invention, PA56 resin is used as the main resin, and its mass fraction in the polyamide composition is more than 35%.

[0020] Preferably, the relative viscosity of the PA56 resin is 2.2 to 3.2.

[0021] More preferably, the relative viscosity of the PA56 resin is 2.4 to 2.8. Using PA56 resin with this relative viscosity results in a polyamide composition with lower release force and higher weld line strength.

[0022] In this invention, the viscosity of the PA56 resin can be measured according to ISO 307-2019 under 96% concentrated sulfuric acid conditions.

[0023] Preferably, the glass fiber is chopped glass fiber.

[0024] Preferably, the average diameter of the cross-section of the glass fiber is 10-13 μm.

[0025] Preferably, the average length of the glass fiber is 2 to 4.5 mm.

[0026] In this invention, the average diameter and average length of the glass fiber cross section can be measured by optical microscopy.

[0027] Preferably, the polyamide composition further includes 1 to 5 parts of a black colorant.

[0028] More preferably, the black colorant is carbon black.

[0029] More preferably, the black colorant is PE-based carbon black masterbatch.

[0030] Preferably, the composite nucleating agent is added in the form of a masterbatch.

[0031] More preferably, the carrier of the masterbatch is PA6 resin.

[0032] More preferably, the relative viscosity of the PA6 resin is 2.4 to 2.8; the viscosity of the PA6 resin can be measured according to ISO 307-2019 under 96% concentrated sulfuric acid conditions.

[0033] More preferably, the content of the composite nucleating agent in the masterbatch is 40-60 wt%.

[0034] In this invention, the mass ratio of amide nucleating agent to talc can be 1.5:1, 1.8:1, 2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1 or 4.5:1.

[0035] Preferably, the composite nucleating agent comprises an amide nucleating agent and talc in a mass ratio of (3-4):1. Controlling the mass ratio of the two within this range results in a polyamide composition with a higher crystallization temperature and lower release force.

[0036] Preferably, the amide nucleating agent is at least one of succinamide nucleating agents, adipamide nucleating agents, phenylenediamide nucleating agents, or organophosphoryl nucleating agents.

[0037] More preferably, the succinamide nucleating agent includes, but is not limited to, diphenylsuccinamide.

[0038] More preferably, the adipamide nucleating agent includes, but is not limited to, diphenylhexadiamide.

[0039] More preferably, the phthalamide nucleating agent includes, but is not limited to, N,N-dicyclohexyl terephthalamide.

[0040] More preferably, the organophosphoramide is at least one of diphenylphosphoramide or diethylphosphoramide.

[0041] Preferably, the average particle size of the talc powder is 8–18 μm.

[0042] In this invention, the average particle size of talc powder can be measured according to GB / T 19077-2016.

[0043] Preferably, the polyamide composition further includes 0.1 to 4 parts of other additives.

[0044] Preferably, the other additives are at least one of lubricants or antioxidants.

[0045] Optionally, the lubricant is an ester-based lubricant, including but not limited to at least one of EBS, stearamide, or erucamide.

[0046] Optionally, the antioxidant includes, but is not limited to, at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris[2,4-di-tert-butylphenyl]phosphite.

[0047] The preparation method of the above polyamide composition includes the following steps: mixing the components, melt extruding, and granulating to obtain the polyamide composition.

[0048] Preferably, the temperature of the melt extrusion is 220–280°C; the screw length-to-diameter ratio of the extruder for the melt extrusion is 35–50:1, and the screw speed is 300–600 r / min.

[0049] The application of the above-mentioned polyamide composition in the preparation of automotive parts is also within the scope of protection of this invention.

[0050] Preferably, the automotive component is a carbon canister, an engine cylinder head cover, or an oil pan.

[0051] Compared with the prior art, the beneficial effects of the present invention are:

[0052] This invention uses PA56 resin as the main resin, and also adds glass fiber, as well as amide nucleating agent and talc as composite nucleating agent. The resulting polyamide composition not only has a high crystallization temperature, but also low demolding force and good weld line strength. Detailed Implementation

[0053] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0054] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0055] PA56 resin #1: Ecopent-1273, Kaisai Biotechnology, relative viscosity 2.8;

[0056] PA56 resin #2: Ecopent-1251, Kaisai Biotechnology, relative viscosity 2.4;

[0057] PA56 resin #3: Ecopent-3100, Kaisai Biotechnology, relative viscosity 3.1;

[0058] Fiberglass: China Jushi, ECS10-03-568H, chopped fiberglass;

[0059] Black colorant #1: PE2642, Cabot;

[0060] Other additives #1: Lubricant, ethylene bis-stearamide, commercially available;

[0061] Other adjuvant #2: Antioxidant, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available;

[0062] Talc: Huamei, AH-1250N6, average particle size 10-15μm;

[0063] Amide nucleating agent #1: Diphenylhexamethylenediamine, commercially available;

[0064] Amide nucleating agent #2: NN dicyclohexyl terephthalamide, commercially available;

[0065] Amide nucleating agent #3: Diphenylbutyramide, commercially available;

[0066] Amide nucleating agent #4: Diethylphosphamide, commercially available;

[0067] Other nucleating agent A#: Nano clay, ADINS CLAY 20, TOLSA;

[0068] Other nucleating agents B#: Sodium lignite, LICOMONT NAV101PWD, Clariant;

[0069] Other nucleating agents C#: Aluminum hydroxide, TMP-6, Shanxi Provincial Chemical Research Institute;

[0070] Composite nucleating agent 1#: self-made, the preparation process is as follows: amide nucleating agent 1# and talc powder are mixed at a mass ratio of 3:1, and then mixed with an equal amount of PA6 resin (Jiangsu Haiyang, PA6HY2500A, relative viscosity 2.4). The mixture is then melt-blended through a single-screw extrusion stage at a certain temperature (220~250℃) to obtain composite nucleating agent 1# (active ingredient content is 50wt%).

[0071] Composite nucleating agent 2#: self-made, the difference from composite nucleating agent 1# is that the mass ratio of amide nucleating agent 1# and talc is 4:1;

[0072] Composite nucleating agent 3#: self-made, the difference from composite nucleating agent 1# is that the mass ratio of amide nucleating agent 1# and talc is 2:1;

[0073] Composite nucleating agent 4#: self-made, the difference from composite nucleating agent 1# is that amide nucleating agent 1# is replaced with amide nucleating agent 2#;

[0074] Composite nucleating agent 5#: self-made, the difference from composite nucleating agent 1# is that amide nucleating agent 1# is replaced with amide nucleating agent 3#;

[0075] Composite nucleating agent 6#: self-made, the difference from composite nucleating agent 1# is that amide nucleating agent 1# is replaced with amide nucleating agent 4#;

[0076] Composite nucleating agent 7#: self-made, the difference from composite nucleating agent 1# is that talc is replaced with other nucleating agent A#;

[0077] Composite nucleating agent 8#: self-made, the difference from composite nucleating agent 1# is that amide nucleating agent 1# is replaced with other nucleating agent B#;

[0078] Composite nucleating agent 9#: self-made, the difference from composite nucleating agent 1# is that amide nucleating agent 1# is replaced with other nucleating agent C#;

[0079] Single nucleating agent 1#: self-made, unlike composite nucleating agent 1#, it does not contain talc.

[0080] Single nucleating agent 2#: self-made, unlike composite nucleating agent 1#: does not contain amide nucleating agent 1#.

[0081] Unless otherwise specified, all components (e.g., glass fiber, other additives 1#, other additives 2#) used in each parallel embodiment and comparative example are the same commercially available products.

[0082] The polyamide compositions of the embodiments and comparative examples of the present invention were prepared by the following preparation method:

[0083] (1) Weigh each component according to the proportion, put each component into a high-speed mixer, mix them evenly to obtain a mixture.

[0084] (2) The mixture is fed into a twin-screw extruder. The extruder temperature is set sequentially for each zone as follows: 220℃, 240℃, 245℃, 250℃, 260℃, 270℃, 280℃, 275℃, 265℃, and 240℃. The rotation speed is 500 r / min, and the screw length-to-diameter ratio is 40:1. After mixing, melting, homogenizing, and extrusion granulation, a polyamide composition is obtained.

[0085] The polyamide compositions provided in the embodiments and comparative examples of the present invention were subjected to performance testing according to the following test methods:

[0086] 1) Crystallization temperature: DSC test was conducted according to ISO 11357-2011 standard, with a heating and cooling rate of 10℃ / min.

[0087] 2) Demolding force: Using a customized demolding force injection molding machine, special parts are injection molded under certain temperature and pressure. Five molds are continuously injected and the average value is calculated. The demolding force is monitored by a sensor.

[0088] 3) Weld line strength: Tensile specimens of double-sided injection weld lines were tested according to ISO 527-2019 standard, with a tensile rate of 10 mm / min.

[0089] Examples 1-10

[0090] Examples 1-10 provide a series of polyamide compositions, the formulations of which are shown in Table 1 (the amounts of composite nucleating agents in each example in Table 1 are converted to the amount of active ingredients).

[0091] Table 1. Formulations (parts by weight) for Examples 1-10

[0092]

[0093]

[0094] Comparative Examples 1-5

[0095] Comparative Examples 1-5 provide a series of polyamide compositions, the formulations of which are shown in Table 2 (the amounts of composite nucleating agent / single nucleating agent in each comparative example in Table 2 are the amounts converted to active ingredients).

[0096] Table 2 shows the formulations (parts by weight) for Comparative Examples 1–5.

[0097]

[0098] The properties of the polyamide compositions of each embodiment and comparative example were determined according to the test methods mentioned above, and the test results are shown in Table 3.

[0099] Table 3. Performance test results of the polyamide compositions in each example and comparative example.

[0100] Test Results Crystallization temperature (°C) Demolding force (N) Fusion line strength (MPa) Example 1 219 580 95 Example 2 220 725 101 Example 3 215 640 80 Example 4 217 565 93 Example 5 216 570 89 Example 6 218 640 85 Example 7 217 650 90 Example 8 216 530 92 Example 9 215 535 94 Example 10 218 610 85 Comparative Example 1 218 975 75 Comparative Example 2 216 980 73 Comparative Example 3 215 990 70 Comparative Example 4 216 1025 65 Comparative Example 5 214 1130 67 .

[0101] As can be seen from Table 3:

[0102] The polyamide compositions of Examples 1 to 10 all have crystallization temperatures above 215°C, demolding forces below 725N, and weld line strengths above 80MPa, indicating that the polyamide compositions of the present invention not only have high crystallization temperatures and low demolding forces, but also good weld line strengths.

[0103] The types of composite nucleating agents added in Comparative Examples 1-3 were unsuitable, resulting in high release force and low weld line strength in the polyamide compositions. In Comparative Example 4, the nucleating agent added was only an amide-based nucleating agent, leading to high release force and low weld line strength in the polyamide composition. In Comparative Example 5, the nucleating agent added was only talc, resulting in a lower crystallization temperature, higher release force, and lower weld line strength in the polyamide composition.

[0104] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polyamide composition characterized in that, The polyamide composition comprises the following components in parts by weight: PA56 resin 40-90 parts, Glass fiber 10-50 parts, Composite nucleating agent 1-3 parts, The composite nucleating agent comprises an amide nucleating agent and talc in a mass ratio of (1.5-4.5):1; the amide nucleating agent is at least one of succinamide nucleating agent, adipamide nucleating agent, phthalamide nucleating agent or organic phosphoric acid acyl nucleating agent.

2. The polyamide composition according to claim 1, characterized in that, The relative viscosity of the PA56 resin is 2.2-3.

2.

3. The polyamide composition according to claim 1, characterized in that, The glass fiber is short-cut glass fiber.

4. The polyamide composition according to claim 1, characterized in that, The composite nucleating agent is added in the form of master batch.

5. The polyamide composition according to claim 1, characterized in that, The talc has an average particle size of 8-18 μm.

6. The polyamide composition according to claim 1, characterized in that, The polyamide composition further comprises other auxiliary agent 0.1-4 parts and black colorant 1-5 parts.

7. The polyamide composition according to claim 6, characterized in that, The other auxiliary agent is at least one of lubricant or antioxidant.

8. Process for the production of the polyamide composition according to any one of claims 1 to 7, characterized in that, The polyamide composition is prepared by mixing the components, melt extruding and granulating.

9. Use of the polyamide composition according to any one of claims 1-7 in the preparation of automobile parts.

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