Polyamide material, and preparation method therefor and use thereof

Abstract

The present application discloses a polyamide material, and a preparation method therefor and a use thereof. The polyamide material of the present application comprises the following components in parts by weight: 49-97 parts of a polyamide resin, 0-50 parts of a filler, 1-5 parts of ultra-high-molecular-weight polyethylene, 1-5 parts of linear low-density polyethylene grafted maleic anhydride (LLDPE-g-MAH) and 1-3 parts of an auxiliary agent. According to the present application, by adding ultra-high-molecular-weight polyethylene and LLDPE-g-MAH into the polyamide material, the strength of the material is not reduced while reducing the surface friction of the material, such that the polyamide material has the characteristics of low noise and high mechanical properties.

Description

A polyamide material and its preparation method and application Technical Field

[0001] The present invention relates to the field of polyamide composite materials, and specifically relates to a polyamide material and a preparation method and application thereof. Background Art

[0002] Polyamide (PA), also known as nylon, is derived from the polycondensation of dibasic acids and diamines or amino acids. It is a general term for resins containing repeating amide groups in their molecular chains and is one of the four major engineering materials. Based on their chemical structure, polyamides can be divided into three categories: aliphatic polyamides, aliphatic-aromatic polyamides, and aromatic polyamides. Polyamides offer excellent mechanical properties, heat resistance, wear resistance, chemical resistance, flame retardancy, and self-lubrication. 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 and are often used in conjunction with other components. However, they often produce noise during use, such as when automotive interior components rub against fabrics. Attempting to improve noise levels by reducing the content of fillers such as glass fiber, or even eliminating fillers altogether, thereby reducing related product properties, ultimately fails to meet actual mechanical requirements, resulting in a significant reduction in toughness.

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

[0004] In response to the noise problem often occurring in the above-mentioned polyamide materials, this application improves the noise by improving the surface friction of the polyamide material, while also achieving the purpose of maintaining the high performance of the polyamide material. A polyamide material, a preparation method and application thereof will be provided.

[0005] This application provides the following technical solutions:

[0006] A polyamide material comprising the following components in parts by weight: 49-97 parts of polyamide resin, 0-50 parts of filler, 1-5 parts of ultra-high molecular weight polyethylene, 1-5 parts of linear low-density polyethylene grafted with maleic anhydride, and 1-3 parts of an additive;

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

[0008] In some embodiments, the grafting rate of the maleic anhydride grafted linear low density polyethylene is 1.2-1.3%.

[0009] In some embodiments, the mass ratio of the ultra-high molecular weight polyethylene to the maleic anhydride grafted linear low density polyethylene is 0.5-2.5.

[0010] In some embodiments, the number average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 2 million.

[0011] In some embodiments, the filler includes at least one of glass fiber, talc, wollastonite, glass beads, kaolin, and calcium carbonate.

[0012] In some embodiments, the auxiliary agent includes 0.5-1.5 parts by weight of a lubricant and 0.5-1.5 parts by weight of an antioxidant.

[0013] In some embodiments, the method for preparing the maleic anhydride grafted linear low density polyethylene comprises the following steps: mixing linear low density polyethylene, maleic anhydride and peroxide, and extruding to obtain the maleic anhydride grafted linear low density polyethylene.

[0014] In some embodiments, at least one of the following is included:

[0015] The extrusion temperature is 170-190°C;

[0016] The extrusion speed is 20-50 rpm;

[0017] The weight portion of the linear low-density polyethylene is 94-97.6 parts;

[0018] The weight portion of the maleic anhydride is 2-5 parts;

[0019] The weight portion of the peroxide is 0.4-1 part.

[0020] The present application provides a method for preparing the polyamide material, comprising the following steps:

[0021] The polyamide material is obtained by uniformly mixing polyamide resin, ultra-high molecular weight polyethylene, linear low density polyethylene grafted with maleic anhydride and an auxiliary agent, adding optional fillers, and performing melt blending and extrusion granulation.

[0022] The present application provides applications of the polyamide material in electrical and electronic parts, automotive components, furniture, and building materials.

[0023] Compared with the prior art, the present invention has the following beneficial effects: by adding ultra-high molecular weight polyethylene and LLDPE-g-MAH to the polyamide material, the present invention utilizes the polarity at one end and the non-polarity at the other end of the LLDPE-g-MAH molecular chain to fully disperse the ultra-high molecular weight polyethylene in the polyamide, thereby reducing the surface friction of the material; at the same time, since the ultra-high molecular weight polyethylene has a large molecular weight and severe entanglement, the LLDPE-g-MAH can disentangle the UHMWPE molecular weight, thereby allowing the UHMWPE molecular weight to be more fully expanded, thereby 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 DESCRIPTION

[0024] A polyamide material comprises the following components in parts by weight: 49-97 parts of a polyamide resin, 0-50 parts of a filler, 1-5 parts of an ultra-high molecular weight polyethylene (UHMWPE), 1-5 parts of a linear low-density polyethylene grafted with maleic anhydride (LLDPE-g-MAH), and 1-3 parts of an additive;

[0025] The grafting rate of the linear low-density polyethylene grafted with maleic anhydride is 1-1.5%.

[0026] The present application adds ultra-high molecular weight polyethylene and LLDPE-g-MAH to a polyamide material, and utilizes the bipolarity of LLDPE-g-MAH to fully disperse the ultra-high molecular weight polyethylene in the polyamide, thereby reducing the surface friction of the material. At the same time, since the ultra-high molecular weight polyethylene has a large molecular weight and severe entanglement, LLDPE-g-MAH can disentangle the UHMWPE molecular weight, thereby allowing the UHMWPE molecular weight to be more fully expanded, thereby 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.

[0027] In some embodiments, in the polyamide material, the mass content of the polyamide resin is not less than 35%.

[0028] The type of the polyamide resin can be selected from conventional types in the field to achieve the purpose of the present application. 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 is no special requirement 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.

[0029] The linear low-density polyethylene grafted with maleic anhydride, also known as maleic anhydride-grafted linear low-density polyethylene, as described herein, refers to a linear low-density polyethylene (LLDPE) in which maleic anhydride molecules are grafted onto the molecular chain. This allows the product to possess both the good processability and other excellent properties of polyethylene and the reactivity and strong polarity of maleic anhydride polar molecules. Linear low-density polyethylene (LLDPE) refers to a molecular structure formed by copolymerizing ethylene with a small amount of α-olefins on a linear ethylene backbone, with very short comonomer side chains. Its density is typically 0.918 to 0.935 g / cm 3 The grafting rate described in this application refers to the percentage of the mass of the grafted chains in the grafted copolymer to the mass of the entire copolymer.

[0030] In some embodiments, 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 acid-base titration (chemical titration).

[0031] In some embodiments, the method for preparing the linear low-density polyethylene grafted with maleic anhydride comprises 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.

[0032] In some embodiments, the extrusion temperature is 170-190°C.

[0033] In some embodiments, the extrusion speed is 20-50 rpm.

[0034] In some embodiments, the weight portion of the linear low-density polyethylene is 94-97.6 parts; the weight portion of the maleic anhydride is 2-5 parts; and the weight portion of the peroxide is 0.4-1 part.

[0035] There are no particular requirements for the melt flow rate of the linear low density polyethylene, such as can be measured according to ASTM D 1238-10, under a load of 2.16 kg and a temperature of 190° C. In some embodiments, the melt flow rate of the linear low density polyethylene is 0.1 g / 10 min to 60.0 g / 10 min when measured according to ASTM D 1238-10, under a load of 2.16 kg and a temperature of 190° C.

[0036] In some embodiments, the peroxide comprises one of dicumyl peroxide, benzoyl peroxide, di-tert-butyl peroxide, and dicumyl hydroperoxide.

[0037] In some embodiments, the mass ratio of the ultra-high molecular weight polyethylene to the linear low density polyethylene grafted with maleic anhydride is 0.2-5.

[0038] In some embodiments, the mass ratio of the ultra-high molecular weight polyethylene to the linear low density polyethylene grafted with maleic anhydride is 0.5-2.5.

[0039] The ultra-high molecular weight polyethylene described herein is an unbranched linear polyethylene with a molecular weight of 1 million or more. In some embodiments, the ultra-high molecular weight polyethylene has a number average molecular weight of 1 million to 2 million.

[0040] The molecular weight of the ultra-high molecular weight polyethylene is preferably 1-2 million. In some embodiments, the molecular weight can be expressed as a number average molecular weight, which can be measured using conventional number average molecular weight testing methods in the art, such as gel permeation chromatography.

[0041] In some embodiments, the weight portion of the filler can be 1-10 parts, or 11-19 parts, or 20-50 parts, or 30-40 parts, or a specific point value in the above range, which is not detailed here due to space limitations.

[0042] In some embodiments, the filler includes at least one of glass fiber, talc, wollastonite, glass beads, kaolin, and calcium carbonate.

[0043] In some embodiments, the auxiliary agent includes at least one of a lubricant, an antioxidant, a colorant, a flame retardant, and an antioxidant.

[0044] In some embodiments, 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) hexanediamine (antioxidant 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate (antioxidant PEP-36).

[0045] As a further preferred embodiment of the present application, the lubricant includes at least one of zinc stearate, calcium stearate, ethylene bisstearamide (lubricant TAF), and polyethylene wax.

[0046] A preparation method of a polyamide material comprises the following steps: uniformly mixing polyamide resin, ultra-high molecular weight polyethylene, linear low density polyethylene grafted maleic anhydride and an auxiliary agent, adding optional fillers, and performing melt blending and extrusion granulation to obtain the polyamide material.

[0047] In some embodiments, polyamide resin, ultra-high molecular weight polyethylene, linear low density polyethylene grafted maleic anhydride and additives are uniformly mixed and then added to the extruder from the main feeding port; optionally, the filler is added to the extruder from the side feeding port.

[0048] This application also includes the use of the polyamide material in electrical and electronic parts, automobile parts, furniture, and building materials.

[0049] DETAILED DESCRIPTION

[0050] To better illustrate the purpose, technical solutions, and advantages of this application, the present application will be further described below through specific examples. Unless otherwise specified, the experimental methods used in the examples and / or comparative examples are conventional methods; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0051] Table 1 Models and sources of raw materials used in the examples and comparative examples

[0052] Examples 1-13 and Comparative Examples 1-12

[0053] A method for preparing a polyamide material mainly comprises the following steps:

[0054] (1) According to the formula in Table 2, polyamide resin, additives, ultra-high molecular weight polyethylene and LLDPE-g-MAH were weighed respectively, and the components were mixed uniformly and then added to the extruder;

[0055] (2) The optional filler is then added to the extruder from the side feed, fully melted and mixed uniformly, and extruded into granules to obtain a polyamide material.

[0056] The preparation method of polyethylene grafted with maleic anhydride specifically comprises the following steps: extruding polyethylene, maleic anhydride (MAH) and dicumyl peroxide (DCP) in a twin-screw extruder according to the following ratio to obtain polyethylene grafted with maleic anhydride;

[0057] The parameters involved are as follows, and the following % are all mass percentages:

[0058] LLDPE-g-MAH1: screw speed 35 rpm, temperature 180°C; LLDPE: 95.2%, MAH: 4%, DCP: 0.8%, grafting rate 1.5%;

[0059] LLDPE-g-MAH2: screw speed 35 rpm, temperature 170°C; LLDPE: 97.6%, MAH: 2%, DCP: 0.4%, grafting rate 1.2%;

[0060] LLDPE-g-MAH3: screw speed 35 rpm, temperature 190°C; LLDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0061] LLDPE-g-MAH4: screw speed 35 rpm, temperature 180°C; LLDPE: 94.8%, MAH: 4%, DCP: 1.2%, grafting rate 1.0%.

[0062] LLDPE-g-MAH5: screw speed 35 rpm, temperature 180°C; LLDPE: 98.2%, MAH: 1%, DCP: 0.8%, grafting rate 0.5%.

[0063] LLDPE-g-MAH6: screw speed 50 rpm, temperature 180°C; LLDPE: 95.2%, MAH: 5%, DCP: 0.8%, grafting rate 1.8%;

[0064] HDPE-g-MAH: screw speed 35 rpm, temperature 190°C; HDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0065] LDPE-g-MAH: screw speed 35 rpm, temperature 190°C; LDPE: 94%, MAH: 5%, DCP: 1%, grafting rate 1.3%;

[0066] The polyamide materials prepared in each embodiment and comparative example were subjected to mechanical and noise test items:

[0067] (1) Tensile strength is tested according to ISO 527-2019 standard:

[0068] (2) Notched impact strength is tested according to ISO 179 / 1Ea-2010;

[0069] (3) Noise test: Test the noise decibels produced by the metal indenter during repeated movement on the plastic plate. The load of the metal indenter is 20N and the speed is 1000mm / min.

[0070] Table 2

[0071] Table 2

[0072] It can be seen from the above embodiments that the polyamide material of the present application is a low-noise and high-mechanical-performance polyamide material, wherein the noise is as low as 46-54dB, the tensile strength can reach 78-215MPa, and the notched impact strength can reach 7-20MPa.

[0073] It can be seen from Example 1 and Comparative Examples 1-5 that only when LLDPE-g-MAH and UHMWPE cooperate with each other can the purpose of reducing the noise of the polyamide material without reducing the strength of the material be achieved.

[0074] It can be seen from Examples 1-4 and Comparative Examples 7-8 that the grafting rate of LLDPE-g-MAH has an impact on the properties of the polyamide material, and the preferred grafting rate is 1.2-1.3%.

[0075] It can be seen from Examples 1 and 5-7 that when the mass ratio of UHMWPE to LLDPE-g-MAH is 0.5-2.5, the performance of the material is better.

[0076] It can be seen from Examples 1, 10-11 and Comparative Example 3 that the UHMWPE material with a number average molecular weight of 1-2 million has better performance.

[0077] It can be seen from Example 1 and Comparative Examples 9-11 that the appropriate addition amounts of UHMWPE and LLDPE-g-MAH are 1-5 parts by weight, respectively.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

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

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

3. The polyamide material according to claim 2, characterized in that The mass ratio of the ultra-high molecular weight polyethylene to the linear low density polyethylene grafted with maleic anhydride is 0.5-2.

5.

4. The polyamide material according to claim 1, characterized in that The number average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 2 million.

5. The polyamide material according to claim 1, characterized in that The filler includes at least one of glass fiber, talc, wollastonite, glass microbeads, kaolin and calcium carbonate.

6. The polyamide material according to claim 1, characterized in that The auxiliary agent includes 0.5-1.5 parts by weight of lubricant and 0.5-1.5 parts by weight of antioxidant.

7. The polyamide material according to claim 1, characterized in that The method for preparing the maleic anhydride grafted linear low-density polyethylene comprises the following steps: mixing linear low-density polyethylene, maleic anhydride and peroxide, and extruding to obtain the maleic anhydride grafted linear low-density polyethylene.

8. The polyamide material according to claim 7, characterized in that Include at least one of the following: The extrusion temperature is 170-190°C; The extrusion speed is 20-50rpm; The weight portion of the linear low-density polyethylene is 94-97.6 parts; The weight portion of the maleic anhydride is 2-5 parts; The weight portion of the peroxide is 0.4-1 part.

9. A method for preparing a polyamide material according to any one of claims 1 to 8, characterized in that: The steps include: The polyamide resin, ultra-high molecular weight polyethylene, linear low-density polyethylene grafted with maleic anhydride and an auxiliary agent are uniformly mixed, and then an optional filler is added, and the polyamide material is obtained through melt blending and extrusion granulation.

10. Use of the polyamide material according to any one of claims 1 to 8 in electrical and electronic parts, automobile parts, furniture and building materials.

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