Polyamide material, method for the production thereof and use thereof

Abstract

The application belongs to the field of polyamide composite materials, and specifically discloses a polyamide material, a preparation method and application thereof.The polyamide material comprises the following components in parts by weight: 49-97 parts of polyamide resin, 0-50 parts of filler, 1-5 parts of ultrahigh molecular weight polyethylene, 1-5 parts of linear low-density polyethylene grafted maleic anhydride, and 1-3 parts of auxiliary agent.By adding the ultrahigh molecular weight polyethylene and the LLDPE-g-MAH in the polyamide material, the surface friction of the material is reduced while the strength of the material is not reduced, so that the polyamide material has the characteristics of low noise and high mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of polyamide composite materials, specifically relating to a polyamide material, its preparation method, and its application. Background Technology

[0002] Polyamide (PA), also known as nylon, is a resin obtained by the condensation polymerization of diacids and diamines or amino acids. It is a general term for resins containing repeating amide groups on their molecular chains and is one of the four major engineering materials. Based on chemical structure, polyamides can be divided into three categories: aliphatic polyamides, aliphatic-aromatic polyamides, and aromatic polyamides. Polyamides possess excellent mechanical properties, heat resistance, wear resistance, chemical resistance, flame retardancy, and self-lubricating properties. They are also easy to process and have a low coefficient of friction, making them widely used in electrical and electronic components, automobiles, furniture, building materials, and films. Among common polyamide materials, glass fiber reinforced polyamides are often used in engineering components due to their excellent mechanical properties, working in conjunction with other components. However, they often produce noise during use, such as when automotive interior parts rub against fabrics. While reducing the content of fillers like glass fiber or even omitting fillers can lower the product's performance to improve noise levels, the mechanical properties of such products often fail to meet actual requirements, such as a significant reduction in toughness.

[0003] Therefore, there is still a need to develop a material that can maintain high mechanical properties while significantly improving the noise problem. Summary of the Invention

[0004] To address the noise problem commonly found in polyamide materials, this invention improves the surface friction of polyamide materials to reduce noise while maintaining their high performance. It provides a polyamide material, its preparation method, and its applications.

[0005] To achieve the above objectives, the following technical solutions are specifically included:

[0006] A polyamide material comprising the following components in parts by weight: 49-97 parts polyamide resin, 0-50 parts filler, 1-5 parts ultra-high molecular weight polyethylene, 1-5 parts linear low density polyethylene grafted with maleic anhydride (LLDPE-g-MAH), and 1-3 parts additives.

[0007] The grafting rate of the linear low-density polyethylene grafted with maleic anhydride is 1-1.5%.

[0008] This invention reduces surface friction by adding ultra-high molecular weight polyethylene (UHMWPE) and LLDPE-g-MAH to a polyamide material. The bipolar nature of LLDPE-g-MAH allows for thorough dispersion of UHMWPE within the polyamide, while simultaneously reducing surface friction. Furthermore, due to the high molecular weight and severe entanglement of UHMWPE, LLDPE-g-MAH detangles the UHMWPE molecules, allowing them to expand more fully and improving the material's toughness. This achieves the goal of reducing surface friction without compromising material strength. The polyamide resin content in the polyamide material is not less than 35% by mass.

[0009] The polyamide resin can be selected from conventional types in the art to achieve the purpose of this invention. For example, the polyamide resin includes, but is not limited to, at least one of PA6, PA66, PA10, PA11, PA46, PA6T, PA9T, PPA, PA610, PA612, PA1010, PA12, and PA1212. There are no special requirements for the intrinsic viscosity of the polyamide resin. For example, 96% concentrated sulfuric acid can be selected as the solvent for testing according to ISO 307 2019 standard. Optionally, the intrinsic viscosity of the polyamide resin is ≥2.0.

[0010] In a preferred embodiment of the present invention, the grafting rate of the linear low-density polyethylene grafted with maleic anhydride is 1.2-1.3%. The grafting rate of the linear low-density polyethylene grafted with maleic anhydride can be measured by conventional grafting rate testing methods in the art, such as by acid-base titration (chemical titration method).

[0011] As a preferred embodiment of the present invention, the preparation method of the linear low-density polyethylene grafted with maleic anhydride includes the following steps: mixing linear low-density polyethylene, maleic anhydride and peroxide, and extruding to obtain the linear low-density polyethylene grafted with maleic anhydride.

[0012] In a preferred embodiment of the present invention, the extrusion temperature is 170-190°C.

[0013] In a preferred embodiment of the present invention, the extrusion speed is 20-50 rpm.

[0014] In a preferred embodiment of the present invention, the linear low-density polyethylene is 94-97.6 parts by weight; the maleic anhydride is 2-5 parts by weight; and the peroxide is 0.4-1 parts by weight.

[0015] There are no special requirements for the melt flow rate of the linear low-density polyethylene. For example, when measured according to ASTM D1238-10, under a load of 2.16 kg and a temperature of 190 °C, the melt flow rate of the linear low-density polyethylene is 0.1 g / 10 min to 60.0 g / 10 min.

[0016] As a further preferred embodiment of the present invention, the peroxide includes one of dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and dicumyl hydroperoxide.

[0017] In a preferred embodiment of the present invention, the mass ratio of ultra-high molecular weight polyethylene and linear low density polyethylene grafted with maleic anhydride is 0.2-5.

[0018] As a further preferred embodiment of the present invention, the mass ratio of ultra-high molecular weight polyethylene and linear low density polyethylene grafted with maleic anhydride is 0.5-2.5.

[0019] In a preferred embodiment of the present invention, the ultra-high molecular weight polyethylene has a number average molecular weight of 1 million to 2 million.

[0020] A molecular weight of 1-2 million is suitable for ultra-high molecular weight polyethylene. This molecular weight can be expressed as number average molecular weight. The number average molecular weight of ultra-high molecular weight polyethylene can be measured using conventional methods for testing number average molecular weight in this field, such as gel permeation chromatography.

[0021] In a preferred embodiment of the present invention, the weight of the filler can be 1-10 parts, or 11-19 parts, or 20-50 parts, or 30-40 parts, or specific values ​​within the above ranges, which will not be elaborated here due to space limitations.

[0022] In a preferred embodiment of the present invention, the filler includes at least one of glass fiber, talc, wollastonite, glass microspheres, kaolin, and calcium carbonate.

[0023] In a preferred embodiment of the present invention, the additives include at least one of lubricant, antioxidant, colorant, flame retardant, and anti-aging agent.

[0024] As a further preferred embodiment of the present invention, the antioxidant includes at least one of triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and pentaerythritol diphosphate bis(2,6-di-tert-butyl-4-methylphenyl)phosphate (antioxidant PEP-36).

[0025] As a further preferred embodiment of the present invention, the lubricant includes at least one of zinc stearate, calcium stearate, ethylene bis-stearamide (lubricant TAF), and polyethylene wax.

[0026] A method for preparing a polyamide material includes the following steps: mixing polyamide resin, ultra-high molecular weight polyethylene, linear low density polyethylene grafted with maleic anhydride and additives evenly, then adding optional fillers, and obtaining the polyamide material by melt blending and extrusion granulation.

[0027] The present invention also includes the application of the polyamide material described herein in electrical and electronic components, automotive parts, furniture, and building materials.

[0028] Compared with the prior art, the present invention has the following beneficial effects: By adding ultra-high molecular weight polyethylene (UHMWPE) and LLDPE-g-MAH to the polyamide material, the present invention utilizes the polarity of one end and the non-polarity of the LLDPE-g-MAH molecular chain to fully disperse the UHMWPE in the polyamide, thereby reducing the surface friction of the material. At the same time, because the UHMWPE has a large molecular weight and severe entanglement, LLDPE-g-MAH can untangle the UHMWPE molecular weight, thereby allowing the UHMWPE molecular weight to expand more fully, improving the toughness of the material, and achieving the goal of reducing the surface friction of the material without reducing the strength of the material. Detailed Implementation

[0029] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0030] Table 1. Types and sources of raw materials used in the examples and comparative examples.

[0031]

[0032] Examples 1-13 and Comparative Examples 1-12

[0033] A method for preparing a polyamide material mainly includes the following steps:

[0034] (1) Weigh out the polyamide resin, additives, ultra-high molecular weight polyethylene and LLDPE-g-MAH according to the formula in Table 2, mix the components evenly and add them to the extruder;

[0035] (2) Then add the optional filler from the side feed into the extruder, melt it fully and mix it evenly, and extrude and granulate it to obtain the polyamide material.

[0036] The preparation method of polyethylene grafted maleic anhydride specifically includes the following: polyethylene, maleic anhydride (MAH) and dicumyl peroxide (DCP) are extruded in a twin-screw extruder in the following proportions to obtain polyethylene grafted maleic anhydride;

[0037] The parameters mentioned above are as follows, and all percentages below refer to mass percentages:

[0038] LLDPE-g-MAH1: Screw speed 35 rpm, temperature 180℃; LLDPE: 95.2%, MAH: 4%, DCP: 0.8%, grafting rate 1.5%;

[0039] LLDPE-g-MAH2: Screw speed 35 rpm, temperature 170℃; LLDPE: 97.6%, MAH: 2%, DCP: 0.4%, grafting rate 1.2%;

[0040] LLDPE-g-MAH3: Screw speed 35 rpm, temperature 190℃; LLDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0041] LLDPE-g-MAH4: Screw speed 35 rpm, temperature 180℃; LLDPE: 94.8%, MAH: 4%, DCP: 1.2%, grafting rate 1.0%.

[0042] LLDPE-g-MAH5: Screw speed 35 rpm, temperature 180℃; LLDPE: 98.2%, MAH: 1%, DCP: 0.8%, grafting rate 0.5%.

[0043] LLDPE-g-MAH6: Screw speed 50 rpm, temperature 180℃; LLDPE: 95.2%, MAH: 5%, DCP: 0.8%, grafting rate 1.8%;

[0044] HDPE-g-MAH: Screw speed 35 rpm, temperature 190℃; HDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0045] LDPE-g-MAH: Screw speed 35 rpm, temperature 190℃; LDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0046] The polyamide materials prepared in each embodiment and comparative example were subjected to mechanical and noise tests:

[0047] (1) Tensile strength was tested according to ISO 527-2019 standard:

[0048] (2) The notched impact strength was tested in accordance with ISO 179 / 1Ea-2010 standard;

[0049] (3) Noise test: The noise level of the metal indenter during repeated movement of the plastic plate was tested. The load on the metal indenter was 20N and the speed was 1000mm / min.

[0050] Table 2

[0051]

[0052]

[0053] Continued from Table 2

[0054]

[0055]

[0056] As can be seen from the above embodiments, the polyamide material of the present invention is a low-noise, high-mechanical-performance polyamide material, wherein the noise level can reach 46-54dB, the tensile strength can reach 78-215MPa, and the notched impact strength can reach 7-20MPa.

[0057] As can be seen from Example 1 and Comparative Examples 1-5, only when LLDPE-g-MAH and UHMWPE are combined can the polyamide material reduce material noise without reducing material strength.

[0058] As can be seen from Examples 1-4 and Comparative Examples 7-8, the grafting rate of LLDPE-g-MAH has an impact on the properties of polyamide materials, and the preferred grafting rate is 1.2-1.3%.

[0059] As can be seen from Examples 1 and 5-7, the material has better performance when the mass ratio of UHMWPE to LLDPE-g-MAH is 0.5-2.5.

[0060] As can be seen from Examples 1, 10-11 and Comparative Example 3, UHMWPE with a number-average molecular weight of 1 million-2 million has better material properties.

[0061] As can be seen from Example 1 and Comparative Examples 9-11, the appropriate addition amounts of UHMWPE and LLDPE-g-MAH are 1-5 parts by weight, respectively.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polyamide material, characterized in that, The polyamide material comprises the following components by weight: polyamide resin 49-97 parts, filler 0-50 parts, ultra-high molecular weight polyethylene 1-5 parts, linear low density polyethylene grafted maleic anhydride 1-5 parts, and auxiliary agent 1-3 parts. The grafting rate of the linear low density polyethylene grafted maleic anhydride is 1-1.5%, which is a mass percentage. The number average molecular weight of the ultra-high molecular weight polyethylene is 1 million-2 million.

2. The polyamide material of claim 1, wherein, The grafting rate of the linear low density polyethylene grafted maleic anhydride is 1.2-1.3%.

3. The polyamide material of claim 2, wherein, The mass ratio of the ultra-high molecular weight polyethylene and the linear low density polyethylene grafted maleic anhydride is 0.5-2.

5.

4. The polyamide material of claim 1, wherein, The filler comprises at least one of glass fiber, talc, wollastonite, glass microbeads, kaolin, and calcium carbonate.

5. The polyamide material of claim 1, wherein, The auxiliary agent comprises 0.5-1.5 parts by weight of lubricant and 0.5-1.5 parts by weight of antioxidant.

6. The polyamide material of claim 1, wherein, The preparation method of the linear low density polyethylene grafted maleic anhydride comprises the following steps: mixing linear low density polyethylene, maleic anhydride, and peroxide, and then extruding to obtain the linear low density polyethylene grafted maleic anhydride.

7. The polyamide material of claim 6, wherein, The extrusion temperature is 170-190℃. The extrusion rotation speed is 20-50 rpm. The linear low density polyethylene is 94-97.6 parts by weight. The maleic anhydride is 2-5 parts by weight. The peroxide is 0.4-1 part by weight. The method comprises the following steps:

8. A method of producing the polyamide material according to any one of claims 1 to 7, characterized in that, The polyamide resin, the ultra-high molecular weight polyethylene, the linear low density polyethylene grafted maleic anhydride, and the auxiliary agent are uniformly mixed, and then the optional filler is added, and then the mixture is subjected to melt blending and extrusion granulation to obtain the polyamide material.

9. Application of the polyamide material of any one of claims 1-7 in electrical and electronic parts, automobile parts, furniture, and building materials. ​

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