Reinforced nylon material, preparation method thereof and precision part

Abstract

The invention discloses a reinforced nylon material and a preparation method thereof, and a precision part, the reinforced nylon material comprises the following components by mass: 50-70 parts of nylon resin; 5 to 20 parts of glass fiber; 10 to 30 parts of carbon fiber; the nylon resin is formed by polycondensation of diamine and binary acid, and in the nylon resin, the ratio of the methylene group number to the amide group number is n, and n is greater than or equal to 8; the carbon content of the carbon fiber is 92 wt%-96 wt%. According to the formula of the reinforced nylon material, the reinforced nylon material is endowed with good dimensional stability, and meanwhile, the comprehensive mechanical property of the reinforced nylon material is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of polymer composite materials, and specifically relates to a reinforced nylon material and a preparation method and precision parts thereof. Background Art

[0002] Nylon materials have good comprehensive properties, such as high mechanical strength, wear resistance, chemical corrosion resistance, etc., and are widely used in many fields. However, single nylon materials still have shortcomings in some aspects of performance. For example, its strength and modulus need to be improved in some application scenarios with strict mechanical properties, and pure nylon is easy to shrink during the molding process, affecting dimensional stability, limiting its application in precision parts. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a reinforced nylon material and a preparation method and precision parts thereof, so as to improve the dimensional stability and comprehensive mechanical properties of the reinforced nylon material.

[0004] The present invention provides a reinforced nylon material, which comprises the following components calculated by weight:

[0005] Nylon resin: 50-70 parts;

[0006] Glass fiber: 5-20 parts;

[0007] Carbon fiber: 10-30 parts;

[0008] The nylon resin is formed by polycondensation of a diamine and a dibasic acid, and in the nylon resin, the ratio of the number of methylene groups to the number of amide groups is n, and n is ≥ 8;

[0009] The carbon fiber has a carbon content of 92wt% to 96wt%.

[0010] The reinforced nylon material of the present invention, through the cooperation between nylon resin, glass fiber and carbon fiber and the optimization of their dosages, especially by using a specific nylon resin in combination with a specific carbon fiber, endows the reinforced nylon material with good dimensional stability while significantly improving the comprehensive mechanical properties of the reinforced nylon material. Specifically, the nylon resin is formed by polycondensation of diamine and dibasic acid, and the amide groups are arranged in reverse in the molecular chain. This reverse arrangement destroys the symmetry of the chain, making it difficult for the molecular chain to stack regularly, thereby reducing the crystallinity; the reverse arrangement of the amide groups causes the polar parts to cancel each other out, reducing the hydrogen bond density and weakening the strength of the hydrogen bond network, thus also reducing the crystallinity. Furthermore, in the nylon resin, the ratio of the number of methylene groups to the number of amide groups is n, where n≥8. The hydrogen bond density decreases, the attraction between molecular chains weakens, and the crystallinity decreases accordingly. At the same time, the molecular chain of this nylon resin has high flexibility and it is difficult for the molecular chain to maintain regular folded stacking, so the crystallinity will also decrease. Based on this, due to its low crystallinity, the nylon resin of the present invention can significantly improve the dimensional stability of the reinforced nylon material. At the same time, the low crystallinity and high molecular chain flexibility of the nylon resin of the present invention can also significantly improve the impact resistance of the reinforced nylon material. In addition, the carbon content of the carbon fiber of the present invention is 92wt% - 96wt%. On the one hand, it can ensure that the carbon fiber contains enough carbon content to improve the dimensional stability, tensile strength and flexural strength of the reinforced nylon material. On the other hand, it can also avoid excessive carbonization, enhance the inertness of the carbon fiber surface, improve the compatibility with the nylon resin, and enhance the interfacial bonding performance, thereby improving the impact resistance of the reinforced nylon material. Compared with the existing technology, the formula of the reinforced nylon material of the present invention endows the reinforced nylon material with good dimensional stability while significantly improving the comprehensive mechanical properties of the reinforced nylon material.

[0011] The ratio n of the number of methylene groups to the number of amide groups is n = (the number of methylene groups + the number of amide groups) / 2.

[0012] Preferably, 8≤n≤10.

[0013] In the nylon resin of this solution, the ratio of the number of methylene groups to the number of amide groups is n, where 8≤n≤10. It can not only reduce the hydrogen bond density of the reinforced nylon material, weaken the attraction between molecular chains, reduce the crystallinity, and improve the dimensional stability of the reinforced nylon material, but also enable the reinforced nylon material to have good comprehensive mechanical properties.

[0014] Preferably, the carbon content of the carbon fiber is 93wt% - 95wt%.

[0015] The carbon content of the carbon fiber in this solution is 93wt% - 95wt%, which can further ensure that the carbon fiber contains enough carbon content to improve the dimensional stability, tensile properties and flexural properties of the reinforced nylon material; it can also further improve the compatibility with the nylon resin and enhance the interfacial bonding performance, thereby improving the impact resistance of the reinforced nylon material.

[0016] Preferably, the carbon fiber is 15 to 25 parts.

[0017] In this solution, the carbon fiber is 15 to 25 parts, which can further improve the dimensional stability and tensile properties of the reinforced nylon material; it can also further improve the impact resistance of the reinforced nylon material.

[0018] Preferably, the glass fiber is chopped glass fiber.

[0019] Preferably, the reinforced nylon material further includes at least one of a toughening agent, a dispersant, an antioxidant, and a lubricant.

[0020] Preferably, the toughening agent includes maleic anhydride grafted POE.

[0021] Preferably, calculated by mass parts, the reinforced nylon material further includes:

[0022] The toughening agent: 1 to 4 parts;

[0023] The dispersant: 0.1 to 1 part;

[0024] The antioxidant: 0.1 to 1 part;

[0025] The lubricant: 0.1 to 1 part.

[0026] The present invention provides a preparation method of the reinforced nylon material, and the preparation method of the reinforced nylon material includes the following steps:

[0027] S1. Mix the components of the reinforced nylon material except the glass fiber and the carbon fiber evenly, and feed them from the main feeding port of a two-stage side-feeding twin-screw extruder. The glass fiber enters from the first-stage side feeding, and the carbon fiber enters from the second-stage side feeding, and perform melt blending and extrusion molding;

[0028] S2. After cooling, air drying, pelletizing and drying, the reinforced nylon material is obtained.

[0029] The present invention provides a preparation method of the reinforced nylon material. By using a two-stage side-feeding twin-screw extruder, the glass fiber, the carbon fiber, and the nylon resin can be fully blended and fused, promoting interfacial bonding, so that the reinforced nylon material obtains excellent mechanical properties.

[0030] The present invention further provides a precision component, and the precision component includes the reinforced nylon material. The precision component includes at least one of automotive components, electronic and electrical components, mechanical equipment components, and aerospace components. Specific embodiments

[0031] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0032] The raw materials used in Example 1 below are specifically as follows:

[0033] Nylon resin: Shandong Xianglong New Materials Co., Ltd., PA612 (nylon 612), inherent viscosity 2.4;

[0034] Glass fiber: Taishan Fiberglass Co., Ltd., T438G;

[0035] Carbon fiber: Toray Synthetic Fibers Co., Ltd., T700S (carbon content 94 wt%);

[0036] Toughening agent: maleic anhydride grafted POE;

[0037] Dispersant: Guangzhou Haocheng New Materials Co., Ltd., TAF;

[0038] Antioxidant: compounded from phosphite antioxidant 168 and hindered phenol antioxidant 1010, and the mass ratio of antioxidant 168 to antioxidant 1010 is 1:1;

[0039] Lubricant: Guangzhou Quanfeng Chemical Technology Co., Ltd., PETS.

[0040] Example 1

[0041] Calculated by mass parts, the reinforced nylon material of this example includes the following components:

[0042] Nylon resin: 66 parts;

[0043] Glass fiber: 10 parts;

[0044] Carbon fiber: 20 parts;

[0045] Toughening agent: 3 parts;

[0046] Dispersant: 0.3 part;

[0047] Antioxidant: 0.3 part;

[0048] Lubricant: 0.4 part.

[0049] The preparation method of the reinforced nylon material of this example is as follows:

[0050] S1. Mix the components of nylon resin, toughening agent, dispersant, antioxidant and lubricant evenly in a mixer, and then feed them from the main feeding port of a two-stage side-feeding twin-screw extruder. Glass fiber is fed in from the side feeding port of the first stage, and carbon fiber is fed in from the side feeding port of the second stage for melt blending and extrusion molding. Among them, the temperatures of each section of the twin-screw extruder are set as follows: the temperature of the first zone is 200 °C, the temperature of the second zone is 220 °C, the temperature of the third zone is 230 °C, the temperature of the fourth zone is 240 °C, the temperature of the fifth zone is 240 °C, the temperature of the sixth zone is 240 °C, the temperature of the seventh zone is 240 °C, the temperature of the eighth zone is 240 °C, and the temperature of the die head is 250 °C. The vacuum degree (vacuum degree = absolute pressure - atmospheric pressure) is -0.08 Mpa, and the screw speed is 250 rpm;

[0051] S2. After cooling, air drying, pelletizing and drying, the enhanced nylon material is obtained.

[0052] Example 2

[0053] In the components of the enhanced nylon material in this example, except that the nylon resin PA612 is replaced by PA1212 (nylon 1212, purchased from Shandong Dongchen Ruisen New Material Technology Co., Ltd.), the rest are the same as in Example 1.

[0054] The preparation method of the enhanced nylon material in this example is the same as that in Example 1.

[0055] Example 3

[0056] In the components of the enhanced nylon material in this example, except that the carbon fiber T700S is replaced by TR50S (carbon content is 92 wt%, purchased from Mitsubishi Chemical Corporation), the rest are the same as in Example 1.

[0057] The preparation method of the enhanced nylon material in this example is the same as that in Example 1.

[0058] Example 4

[0059] In the components of the enhanced nylon material in this example, except that the carbon fiber is 12 parts, the rest are the same as in Example 1.

[0060] The preparation method of the enhanced nylon material in this example is the same as that in Example 1.

[0061] Comparative Example 1

[0062] In the components of the enhanced nylon material in this example, except that the nylon resin PA612 is replaced by nylon 66 (PA66), the rest are the same as in Example 1.

[0063] The preparation method of the enhanced nylon material in this example is the same as that in Example 1.

[0064] Comparative Example 2

[0065] In this example, except that the nylon resin PA612 in the reinforced nylon material components is replaced by nylon 9T (PA9T), the rest is the same as in Example 1.

[0066] The preparation method of the reinforced nylon material in this example is the same as that in Example 1.

[0067] Comparative Example 3

[0068] In this example, except that the carbon fiber T700S in the reinforced nylon material components is replaced by AS4 (carbon content is 85 wt%, purchased from Hexcel Corporation), the rest is the same as in Example 1.

[0069] The preparation method of the reinforced nylon material in this example is the same as that in Example 1.

[0070] Comparative Example 4

[0071] In this example, except that the carbon fiber T700S in the reinforced nylon material components is replaced by T50 (carbon content is 98 wt%, purchased from SGL Carbon SE, Germany), the rest is the same as in Example 1.

[0072] The preparation method of the reinforced nylon material in this example is the same as that in Example 1.

[0073] Performance Test

[0074] (1) Tensile Strength

[0075] The tensile strength test was carried out with reference to the ISO 527:2012 standard.

[0076] (2) Flexural Strength

[0077] The flexural strength test was carried out with reference to the ISO 178:2019 standard.

[0078] (3) Notched Izod Impact Strength of Simply Supported Beam

[0079] The notched Izod impact strength of simply supported beam test was carried out with reference to the ISO 180:2019 standard.

[0080] (4) Shrinkage Rate

[0081] The shrinkage rate test was carried out with reference to ASTM D955.

[0082] The above-prepared reinforced nylon materials of the examples and comparative examples were subjected to the above performance tests, and the test results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] As can be seen from Table 1:

[0087] The reinforced nylon materials of Examples 1 to 4 all fall within the scope of the reinforced nylon materials protected by the technical solution of the present invention, and all show good test results in the performance tests of tensile strength, flexural strength, notched Izod impact strength, longitudinal shrinkage rate and transverse shrinkage rate. That is, the reinforced nylon material provided by the present invention has good dimensional stability and comprehensive mechanical properties. While the reinforced nylon materials of Comparative Examples 1 to 4 do not fall within the scope of the reinforced nylon materials protected by the technical solution of the present invention, and show significant deterioration in at least one of the performance tests of tensile strength, flexural strength, notched Izod impact strength, longitudinal shrinkage rate and transverse shrinkage rate. That is, the reinforced nylon materials of Comparative Examples 1 to 4 cannot have both good dimensional stability and comprehensive mechanical properties.

[0088] Compared with the nylon resin used in the reinforced nylon material of Example 1 being PA612 (the ratio n of the number of methylene groups to the number of amide groups is 8), the nylon resin used in the reinforced nylon material of Example 2 is PA1212 (the ratio n of the number of methylene groups to the number of amide groups is 11). That is, the ratio n of the number of methylene groups to the number of amide groups of the nylon resin used in the reinforced nylon material of Example 2 is not within the further preferred range of 8 ≤ n ≤ 10. The test results of the reinforced nylon material of Example 2 in terms of tensile strength and flexural strength are worse than those of Example 1. This shows that when the ratio of the number of methylene groups to the number of amide groups of the nylon resin used to prepare the reinforced nylon material is 8 ≤ n ≤ 10, while making the reinforced nylon material have good dimensional stability, it can further improve the comprehensive mechanical properties of the reinforced nylon material.

[0089] Compared with the carbon fiber used in the reinforced nylon material of Example 1 being T700S (carbon content is 94 wt%), the carbon fiber used in the reinforced nylon material of Example 3 is TR50S (carbon content is 92 wt%). That is, the carbon content of the carbon fiber used in the reinforced nylon material of Example 3 is not within the further preferred range of 93 wt% - 95 wt%. The test results of the reinforced nylon material of Example 3 in terms of tensile strength, flexural strength, notched Izod impact strength, longitudinal shrinkage rate and transverse shrinkage rate are worse than those of Example 1. This shows that when the carbon content of the carbon fiber used to prepare the reinforced nylon material is 93 wt% - 95 wt%, it can further improve the dimensional stability and comprehensive mechanical properties of the reinforced nylon material.

[0090] Compared with Example 1 where the mass fraction of carbon fiber used in the reinforced nylon material is 20 parts, the mass fraction of carbon fiber used in the reinforced nylon material of Example 4 is 12 parts. That is, the mass fraction of carbon fiber used in the reinforced nylon material of Example 4 is not within the further preferred range of 15 - 25 parts. The test results of the reinforced nylon material of Example 4 in terms of tensile strength, flexural strength, notched Izod impact strength, longitudinal shrinkage rate, and transverse shrinkage rate are worse than those of Example 1. This shows that when the mass fraction of carbon fiber used to prepare the reinforced nylon material is 15 - 25 parts, the dimensional stability and comprehensive mechanical properties of the reinforced nylon material can be further improved.

[0091] Compared with Example 1 where the nylon resin used in the reinforced nylon material is PA612 (the ratio n of the number of methylene groups to the number of amide groups is 8), the nylon resin used in the reinforced nylon material of Comparative Example 1 is nylon 66 (the ratio n of the number of methylene groups to the number of amide groups is 5). That is, the ratio n of the number of methylene groups to the number of amide groups of the nylon resin used in the reinforced nylon material of Comparative Example 1 is not within the range of n≥8 in the present invention. Compared with Example 1, the test results of the reinforced nylon material of Comparative Example 1 in terms of notched Izod impact strength, longitudinal shrinkage rate, and transverse shrinkage rate are significantly deteriorated. This shows that for the nylon resin used in the reinforced nylon material of the present invention, the ratio of the number of methylene groups to the number of amide groups is n, n≥8. The hydrogen bond density decreases, the attraction between molecular chains weakens, and the crystallinity decreases accordingly. At the same time, the molecular chain of this nylon resin has high flexibility and it is difficult for the molecular chain to maintain regular folded stacking, so the crystallinity also decreases. Based on this, using the nylon resin of the present invention can significantly improve the dimensional stability of the reinforced nylon material due to its low crystallinity. At the same time, the low crystallinity and high molecular chain flexibility of the nylon resin of the present invention can also significantly improve the impact resistance of the reinforced nylon material.

[0092] Compared with Example 1 where the nylon resin used in the reinforced nylon material is PA612 (an aliphatic nylon, the ratio n of the number of methylene groups to the number of amide groups is 8), the nylon resin used in the reinforced nylon material of Comparative Example 1 is nylon 9T (a semi-aromatic nylon formed by the polycondensation reaction of nonanediamine (1,9-nonanediamine) and terephthalic acid, the ratio n of the number of methylene groups to the number of amide groups is 4.5). That is, the nylon resin used in the reinforced nylon material of Comparative Example 1 is not the specific nylon resin of the present invention. Compared with Example 1, the test results of the reinforced nylon material of Comparative Example 2 in terms of notched Izod impact strength, longitudinal shrinkage rate, and transverse shrinkage rate are significantly deteriorated. This shows that using the specific nylon resin of the present invention in the reinforced nylon material can significantly improve the impact resistance and dimensional stability of the reinforced nylon material due to its low crystallinity and high molecular chain flexibility.

[0093] Compared with the carbon fiber used in the reinforced nylon material of Example 1, which is T700S (carbon content is 94 wt%), the carbon fibers used in the reinforced nylon materials of Comparative Example 3 and Comparative Example 4 are AS4 (carbon content is 85 wt%) and T50 (carbon content is 98 wt%) respectively. That is, the carbon content of the carbon fibers used in the reinforced nylon materials of Comparative Example 3 and Comparative Example 4 is not within the range of 92 wt% - 96 wt% of the present invention. Compared with Example 1, the test results of the reinforced nylon material of Comparative Example 3 are significantly deteriorated in terms of tensile strength, flexural strength, notched Izod impact strength, longitudinal shrinkage rate and transverse shrinkage rate. The test result of the notched Izod impact strength of the reinforced nylon material of Comparative Example 4 is significantly deteriorated. Thus, it shows that the carbon content of the carbon fiber of the present invention is 92 wt% - 96 wt%. On the one hand, it can ensure that the carbon fiber contains enough carbon content to improve the dimensional stability, tensile strength and flexural strength of the reinforced nylon material. On the other hand, it can also avoid excessive carbonization to enhance the inertness of the carbon fiber surface, improve the compatibility with the nylon resin, and enhance the interfacial bonding performance, thereby improving the impact resistance of the reinforced nylon material.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. A reinforced nylon material, characterized in that, Calculated by mass parts, the reinforced nylon material comprises the following components: Nylon resin: 50 - 70 parts; Glass fiber: 5 - 20 parts; Carbon fiber: 10 - 30 parts; The nylon resin is formed by polycondensation of diamine and dibasic acid, and in the nylon resin, the ratio of the number of methylene groups to the number of amide groups is n, and n≥8; The carbon fiber has a carbon content of 92wt% - 96wt%.

2. The reinforced nylon material according to claim 1, characterized in that, 8≤n≤10.

3. The reinforced nylon material according to claim 1, characterized in that, The carbon fiber has a carbon content of 93wt% - 95wt%.

4. The reinforced nylon material according to claim 1, characterized in that, The carbon fiber is 15 - 25 parts.

5. The reinforced nylon material according to claim 1, wherein The glass fiber is chopped glass fiber.

6. The reinforced nylon material according to claim 1, characterized in that, The reinforced nylon material further comprises at least one of a toughening agent, a dispersing agent, an antioxidant, and a lubricant.

7. The reinforced nylon material according to claim 6, characterized in that, The toughening agent comprises maleic anhydride grafted POE.

8. The reinforced nylon material according to claim 6, wherein Calculated by mass parts, the reinforced nylon material further comprises: The toughening agent: 1 - 4 parts; The dispersing agent: 0.1 - 1 part; The antioxidant: 0.1 - 1 part; The lubricant: 0.1 - 1 part.

9. A method for preparing the reinforced nylon material according to any one of claims 1 to 8, characterized in that, The preparation method of the reinforced nylon material comprises the following steps: S1. Mix the components of the reinforced nylon material except the glass fiber and the carbon fiber evenly and feed them from the main feed port of a two-stage side-feed twin-screw extruder. The glass fiber enters from the first-stage side feed, and the carbon fiber enters from the second-stage side feed, and perform melt blending and extrusion molding; S2. After cooling, air drying, pelletizing and drying, the reinforced nylon material is obtained.

10. A precision component, characterized in that, The precision parts comprise the reinforced nylon material according to any one of claims 1 - 8, and the precision parts comprise at least one of automotive parts, electronic and electrical parts, mechanical equipment parts, and aerospace parts.

Images