Inorganic mineral powder filled nylon composite with good fracture toughness

Abstract

The application discloses a kind of inorganic mineral powder filling nylon composite materials and preparation method with good fracture toughness, according to weight parts, the nylon composite material includes the following raw material components: nylon resin 60~90 parts;Inorganic mineral powder filler 10~40 parts;Lubricant 0.1~1 parts;Other auxiliary agent 0~15 parts;The inorganic mineral powder filler is spherical, spheroid or flaky metal oxide, the total weight of the nylon resin and inorganic mineral powder filler is 100 parts.The specific inorganic mineral powder is filled in the nylon in the application, which improves the warping problem of the nylon, gives the good surface flatness of the nylon molded product, and also has good fracture toughness (its breaking elongation can be as high as 9%), which widens the application range of the inorganic mineral powder filling nylon composite material.

Description

Technical Field

[0001] This invention belongs to the field of modified plastics and composite materials technology, specifically relating to an inorganic mineral powder-filled nylon composite material with good fracture toughness and its preparation method. Background Technology

[0002] Nylon, as an important engineering plastic, possesses characteristics such as self-lubrication, chemical resistance, and good thermal stability, and is widely used in the automotive and electronics industries. However, the polar amide bonds present in the nylon molecular structure make it highly hygroscopic, resulting in poor dimensional stability of nylon products, making them prone to warping and difficult to maintain their shape.

[0003] To improve the warping problem of nylon injection molded products and ensure their flatness, anti-warping fillers such as glass microspheres, talc, mica powder, and wollastonite are often added to the resin matrix. However, while adding these mineral fillers improves the warping problem of nylon products, it reduces the material's toughness, especially its fracture toughness (elongation at break). It has been verified that nylon composites modified with these mineral fillers, when used in products requiring a certain elongation at break (such as plastic chain plates, automotive interior parts like hollow armrest covers, glove repair switch panels, or speaker covers), are prone to brittle fracture during assembly or use, leading to product scrap or shortened lifespan. Particularly when used as conveyor plastic chain plates, insufficient elongation at break can cause the chain plates to break due to mutual tension (tensile strength around 60 MPa) during transmission, resulting in transportation malfunctions.

[0004] Through extensive experimentation, the inventors were surprised to discover that adding spherical, near-spherical, or flake-shaped metal oxide mineral powders to the nylon system significantly improves the surface warping problem of nylon products while ensuring the good fracture toughness of the nylon composite material, thus broadening the application of nylon composite materials in products with high requirements for surface smoothness and material elongation at break. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem that inorganic mineral powder-filled nylon composite core materials in the prior art lose material toughness, especially fracture toughness, when modified nylon injection molded products warp, and to provide an inorganic mineral powder-filled nylon composite material with good fracture toughness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An inorganic mineral powder-filled nylon composite material with good fracture toughness, comprising the following raw material components by weight:

[0008] 60-90 parts of nylon resin;

[0009] 10-40 parts of inorganic mineral powder filler;

[0010] Lubricant 0.1~1 part;

[0011] Other auxiliary agents: 0-15 parts;

[0012] The inorganic mineral powder filler is a spherical, near-spherical, or plate-shaped metal oxide, and the total weight of the nylon resin and the inorganic mineral powder filler is 100 parts.

[0013] Preferably, the nylon resin is one or more of aliphatic nylon and semi-aromatic nylon.

[0014] Preferably, the aliphatic nylon is one or more of PA6, PA66, PA66 / 6 copolymer, PA6 / 66 copolymer, PA610, PA612, PA1010, PA1012, PA11, and PA12; and the semi-aromatic nylon is one or more of PA6T / 66, PA9T, PAMXD6, and PA6T / 6I.

[0015] Preferably, the metal oxide is selected from one or more of aluminum oxide, iron(II,III) oxide, ferric oxide, magnesium oxide, zinc oxide, and titanium dioxide.

[0016] The other additives are one or more of the following: coupling agents, colorants, antioxidants, toughening agents, plasticizers, light stabilizers, heat stabilizers, mildew inhibitors, pigments, and reinforcing fillers. The specific components of the other additives can be selected according to the actual performance requirements and processing specifications.

[0017] Further preferably, the inorganic mineral powder-filled nylon composite material with good fracture toughness comprises the following raw material components by weight:

[0018] 60-80 parts of nylon resin;

[0019] 20-40 parts of inorganic mineral powder filler;

[0020] Lubricant 0.1~1 part;

[0021] 0.5-1.5 parts of coupling agent;

[0022] The coupling agent is one or more of the following: silane coupling agent, titanate coupling agent, aluminate coupling agent, borate coupling agent, and phosphate coupling agent.

[0023] More preferably, the inorganic mineral powder-filled nylon composite material with good fracture toughness comprises the following raw material components by weight:

[0024] 60-80 parts of nylon resin;

[0025] 20-40 parts of inorganic mineral powder filler;

[0026] Lubricant 0.1~1 part;

[0027] 0.5 to 1 part coupling agent;

[0028] The inorganic mineral powder filler is one or more of spherical alumina and plate alumina, preferably spherical or plate α-phase alumina.

[0029] Another object of the present invention is to provide a method for preparing the above-mentioned inorganic mineral powder-filled nylon composite material with good fracture toughness, comprising the following steps:

[0030] S1: Weigh each component according to the formula, add the weighed nylon resin, inorganic mineral filler, lubricant and other additives into a high-speed mixer and mix evenly to obtain a premix;

[0031] S2: The premix obtained in step S1 is added to the twin-screw extruder through the main feed port, and after melt extrusion and granulation, inorganic mineral powder filled nylon composite material is obtained.

[0032] Another object of the present invention is to provide an use of inorganic mineral filler as an additive for nylon composite materials to improve the elongation at break of its molded parts, wherein the inorganic mineral filler is a spherical, near-spherical or plate-shaped metal oxide, and the amount of the inorganic mineral filler is 10 to 40 parts by weight, and the total weight of the nylon resin and the inorganic mineral filler is 100 parts.

[0033] Another object of the present invention is to provide a nylon molded product, particularly a nylon chain plate for conveying, prepared by injection molding or compression molding of nylon composite material filled with inorganic mineral powder with good fracture toughness as described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention uses spherical or flake-shaped metal oxide mineral powder as a filler to fill the nylon resin matrix, which significantly improves the surface warping problem of nylon molded products, gives the nylon molded products good surface flatness, and at the same time ensures good fracture toughness (its elongation at break can be as high as 9%). This allows it to meet the application requirements of nylon chain plates, hollow armrest box covers, glove maintenance switch panels or speaker covers, which have high requirements for product surface flatness and material fracture toughness, thus broadening the application range of nylon composite materials. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] The raw materials used in the examples and comparative examples are all commercially available; unless otherwise specified, the reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in this technical field.

[0038] In all embodiments and comparative examples of this invention, inorganic mineral powder-filled nylon composite materials were prepared using the following method, with each component weighed according to the weight parts specified in Tables 1-2:

[0039] S1: Weigh out the nylon resin, inorganic mineral filler, lubricant and other additives and add them to a high-speed mixer and mix them evenly to obtain a premix;

[0040] S2: The premix obtained in step S1 is fed into a twin-screw extruder through the main feed port, and after melt extrusion and granulation, an inorganic mineral powder filled nylon composite material is obtained; wherein, the screw length-to-diameter ratio of the twin-screw extruder is 40:1, the screw barrel temperature is 220~320 ℃, and the screw speed is 300 rpm~450 rpm.

[0041] Performance testing methods:

[0042] (1) Tensile strength: Tested according to ISO 527-1-2019 standard, test conditions: 23℃;

[0043] (2) Elongation at break: Tested according to ISO 527-1-2019 standard, test conditions: 23℃;

[0044] (3) Warpage of the product: The product was injection molded into a large square piece with a size of 90mm×90mm×6mm using an injection molding machine, and the evaluation was carried out by visual inspection.

[0045] The content and performance test results of each component in the inorganic mineral powder filled nylon composite materials of Examples 1-13 and Comparative Examples 1-9 are shown in Tables 1-2.

[0046] Table 1

[0047]

[0048] Table 2

[0049]

[0050] As can be seen from the experimental data of the examples and comparative examples in Tables 1 and 2, filling a certain amount of spherical or plate-shaped metal oxide mineral powder into the nylon resin matrix results in nylon composite materials with tensile strength exceeding 68 MPa and elongation at break exceeding 4%. Compared to commonly used anti-warping fillers and other conventional inorganic mineral powder-filled nylon systems, this significantly improves the fracture toughness of the nylon composite material at the same filler content, demonstrating the unexpected technical effects achieved by this invention. The inorganic mineral powder-filled nylon composite material of this invention can achieve an elongation at break as high as 9% by controlling the component type and content. Even when filling a certain amount of spherical or plate-shaped metal oxide mineral powder into a glass fiber reinforced nylon system, the elongation at break of the prepared nylon composite material can be maintained above 3.6%, and the surface flatness of the injection-molded large square sheets is good.

[0051] As can be seen from Comparative Example 8 and Examples 5-8, spherical metal oxide mineral powder needs to be used within a specific range to ensure that the prepared nylon composite material maintains good fracture toughness. When the amount exceeds a certain level (more than 40% of the total amount of inorganic mineral powder and nylon resin matrix), the elongation at break of the prepared nylon composite material will show a downward trend.

[0052] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A good fracture toughness inorganic mineral powder filled nylon composite material, characterized in that, comprising the following raw material components by weight: nylon resin 60-90 parts; inorganic mineral powder filler 10-40 parts; lubricant 0.1-1 part; other additives 0-15 parts; the inorganic mineral powder filler is spherical, spherical or flaky metal oxide, the total weight of the nylon resin and the inorganic mineral powder filler is 100 parts, and the metal oxide is selected from one or more of aluminum oxide, triiron tetroxide, diiron trioxide, magnesium oxide, zinc oxide and titanium dioxide.

2. The good fracture toughness inorganic mineral powder filled nylon composite material according to claim 1, characterized in that, the nylon resin is one or more of aliphatic nylon and semi-aromatic nylon.

3. The good fracture toughness inorganic mineral powder filled nylon composite material according to claim 2, characterized in that, the aliphatic nylon is one or more of PA6, PA66, PA66 / 6 copolymer, PA6 / 66 copolymer, PA610, PA612, PA1010, PA1012, PA11 and PA12; and the semi-aromatic nylon is one or more of PA6T / 66, PA9T, PA MXD6 and PA6T / 6I.

4. The good fracture toughness inorganic mineral powder filled nylon composite material according to claim 1, characterized in that, the other additives are one or more of coupling agents, colorants, antioxidants, toughening agents, plasticizers, light stabilizers, heat stabilizers, mildewproofing agents, pigments and reinforcing fillers.

5. The good fracture toughness inorganic mineral powder filled nylon composite material according to claim 1, characterized in that, comprising the following raw material components by weight: nylon resin 60-80 parts; inorganic mineral powder filler 20-40 parts; lubricant 0.1-1 part; coupling agent 0.5-1.5 parts; the coupling agent is one or a combination of several of silane coupling agent, titanate coupling agent, aluminate coupling agent, borate coupling agent and phosphate coupling agent.

6. The good fracture toughness inorganic mineral powder filled nylon composite material according to claim 5, characterized in that, comprising the following raw material components by weight: nylon resin 60-80 parts; inorganic mineral powder filler 20-40 parts; lubricant 0.1-1 part; coupling agent 0.5-1 part; the inorganic mineral powder filler is one or more of spherical aluminum oxide and flaky aluminum oxide.

7. A preparation method of the good fracture toughness inorganic mineral powder filled nylon composite material according to any one of claims 1-6, characterized in that, comprising the following steps: S1: weighing each component according to the ratio, adding the weighed nylon resin, inorganic mineral powder filler, lubricant and other additives into a high-speed mixer to mix uniformly, to obtain a premix; S2: adding the premix obtained in step S1 into a twin-screw extruder from a main feeding port, and performing melt extrusion and granulation to obtain the inorganic mineral powder filled nylon composite material.

8. Use of inorganic mineral filler as an additive for nylon composite material to improve the elongation at break of nylon products, characterized in that, ​ ​ ​ ​ The inorganic mineral filler is a spherical, spheroidal or flaky metal oxide, the amount of the inorganic mineral filler is 10-40 parts by weight, the total weight of the nylon resin and the inorganic mineral filler is 100 parts, and the metal oxide is selected from one or more of aluminum oxide, triiron tetroxide, diiron trioxide, magnesium oxide, zinc oxide and titanium dioxide.

9. A nylon product, characterized in that, The nylon composite material with good fracture toughness and filled with inorganic mineral powder according to any one of claims 1-6 is prepared by injection molding or compression molding.

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