A polyamide composition, its preparation and use

Abstract

This invention discloses a polyamide composition comprising, by weight, the following components: 70-80 parts polyamide; 10-20 parts wollastonite; 10-20 parts kaolin; 0.3-3 parts hyperbranched polyester; and 0.3-3 parts silane coupling agent. This invention utilizes the combination of wollastonite and kaolin, under the synergistic effect of the silane coupling agent and hyperbranched polyester, to improve the compatibility, flowability, and crystallinity of wollastonite, kaolin, and polyamide resin. This not only improves weld line strength but also enhances surface gloss.

Description

Technical Field

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

[0002] Modified polyamides possess excellent comprehensive properties, including good mechanical properties, chemical resistance, and heat resistance, making them widely used in internal load-bearing components and outer shell parts in industries such as rail transportation, consumer electronics, power tools, and shared bicycles. Because polyamide resins inherently exhibit significant shrinkage, introducing fillers helps improve dimensional stability. However, since fillers such as wollastonite, kaolin, and mica powder are dispersed within the resin matrix, the bonding strength at the material flow convergence points during injection molding is often weak, resulting in significant strength issues that affect functionality, especially for components that need to withstand certain burst pressures.

[0003] In addition, when a single product is used as an appearance component, high requirements are often placed on the product's appearance. Mineral-filled nylon systems tend to have a high mineral specific surface area and high irregularity, which can easily cause problems such as appearance and air marks during injection molding.

[0004] Therefore, in current nylon-filled systems, it is often difficult to balance weld line strength and excellent surface appearance. These defects also limit the application scenarios of mineral-filled polyamide materials, especially internal load-bearing components or shell parts in industries such as water treatment, consumer appliances, rail transportation, power tools, and shared bicycles. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical defects and provide a polyamide composition with high weld line strength and high gloss.

[0006] This invention is achieved through the following technical solution: A polyamide composition, by weight, comprises the following components: 70-80 parts of polyamide; 10-20 parts of wollastonite; 10-20 parts of kaolin; 0.3-3 parts of hyperbranched polyester; 0.3-3 parts of coupling agent.

[0007] In this invention, the polyamide content can be 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, etc. The wollastonite content can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc. The kaolin content can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc. The hyperbranched polyester content can be 0.3 parts, 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts, 2.5 parts, 2.7 parts, 3.0 parts, etc. The coupling agent content can be 0.3 parts, 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2.1 parts, 2.3 parts, 2.5 parts, 2.7 parts, 3.0 parts, etc.

[0008] The hyperbranched polyester has a weight-average molecular weight range of 500-6500 g / mol, and its end groups are at least one of terminal carboxyl groups and terminal hydroxyl groups. The weight-average molecular weight of the hyperbranched polyester can be 500 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, etc.

[0009] Preferably, the weight-average molecular weight range of the hyperbranched polyester is 1100-3000 g / mol; Preferred end-carboxyl hyperbranched polyester.

[0010] The molecular weight range of hyperbranched polyesters is determined using gel permeation chromatography (GPC).

[0011] The hyperbranched polyester of the present invention can be a commercially available product or can be obtained by self-production. The main influences are the type of end groups and the molecular weight range.

[0012] The mesh size of the wollastonite and kaolin is 500-1500 mesh. It can be 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh, 1100 mesh, 1200 mesh, 1300 mesh, 1400 mesh, 1500 mesh, etc.

[0013] The silane coupling agent is selected from at least one of epoxy silane coupling agents, amino silane coupling agents, and isocyanate silane coupling agents.

[0014] The polyamide was tested with a 0.01 g / mL concentrated sulfuric acid solution at 25°C using an Ubbelohde viscometer, and the relative viscosity range was 1.6-3.3.

[0015] The polyamide resin is selected from at least one of aliphatic polyamide resin and semi-aromatic polyamide resin; the aliphatic polyamide resin is selected from at least one of PA66, PA46, PA610, PA612, PA56, PA510, PA512, PA910, PA912, PA913, PA914, PA915, PA616, PA936, PA1010, PA1012, PA1013, PA1014, PA1210, PA1212, PA1213, PA1214, PA614, PA613, PA615, PA616, PA5, PA6, PA11, PA12; the semi-aromatic polyamide is selected from at least one of PA MXD6, PA10T, PA10T1010, PA10T66, PA6T, PA6T66, PA9T.

[0016] You may choose to add 0-2 parts of an additive as needed. The additive is selected from at least one of antioxidants and lubricants.

[0017] Preferably, in the polyamide composition of the present invention, the content of polyamide resin is not less than 55 wt%.

[0018] The method for preparing the polyamide composition of the present invention involves mixing the components evenly according to the formula, and then extruding and granulating the mixture through a twin-screw extruder to obtain the polyamide composition. The barrel temperature range is 180-320°C, and the rotation speed range is 200-700 rpm.

[0019] The polyamide composition of the present invention is used to prepare consumer appliances, rail transportation, power tools, shared bicycles, water treatment, etc., preferably injection molded parts in the above industries with structures containing voids or ribs, and with high requirements for appearance and weld line strength.

[0020] The present invention has the following beneficial effects: This invention utilizes the combination of wollastonite and kaolinite, which results in higher bonding strength at the weld line during injection molding compared to other fillers. Furthermore, the synergistic effect of the silane coupling agent and hyperbranched polyester improves the compatibility, flowability, and crystallinity of wollastonite, kaolinite, and polyamide resin, not only further enhancing weld line strength but also reducing the risk of air entrapment during injection molding, thereby improving surface gloss. Detailed Implementation

[0021] 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.

[0022] PA66: PA66 U3600 NC01, Invista; PA6: HY-2500A, Haiyang Chemical Fiber; PA10T: Vicnyl 701 NC001, Zhuhai Wantong Special Engineering Plastics; PA1010: PA1010 G150, Shandong Guangyin New Materials Co., Ltd.; Wollastonite was purchased from Dalian Global Minerals Co., Ltd., and raw materials of different particle sizes were obtained through screening.

[0023] Wollastonite A: Particle size 500 mesh; Wollastonite B: Particle size 1500 mesh; Kaolin was purchased from BASF in Germany, and raw materials of different particle sizes were obtained through screening.

[0024] Kaolin A: Particle size is 500 mesh; Kaolin B: Particle size is 1500 mesh; Mica powder: from Jiangmen Jingda Mica Materials Co., Ltd., particle size 800 mesh, trade name HYC 800 mesh; Hyperbranched polyester A: hydroxyl-terminated, aromatic hyperbranched polyester, molecular weight 920 g / mol, HyPer H301, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester B: hydroxyl-terminated, aliphatic hyperbranched polyester, molecular weight 1100 g / mol, HyPer H102, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester C: terminal hydroxyl group, aliphatic hyperbranched polyester, molecular weight 2400 g / mol, HyPer H103, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester D: hydroxyl-terminated, aliphatic hyperbranched polyester, molecular weight 5200 g / mol, HyPer H104, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester E: terminal carboxyl group, aromatic hyperbranched polyester, molecular weight 950 g / mol, HyPer C201, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester F: terminal carboxyl group, aromatic hyperbranched polyester, molecular weight 1200 g / mol, HyPer C401, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester G: terminal carboxyl group, aromatic hyperbranched polyester, molecular weight 2800 g / mol, HyPer C302, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester H: terminal carboxyl group, aromatic hyperbranched polyester, molecular weight 6400 g / mol, HyPer C103, Wuhan Hyperbranched Resin Technology Co., Ltd. Hyperbranched polyester I: terminal carboxyl group, aromatic polyester polyether structure, molecular weight 2600 g / mol, HyPer C102, Wuhan Hyperbranched Resin Technology Co., Ltd.

[0025] Epoxysilane coupling agent: 3-glycidyl etheroxypropyltrimethoxysilane, Jianghan Fine Chemicals; Aminosilane coupling agent: 3-aminopropyltriethoxysilane, Jianghan Fine Chemicals; Isocyanate silane coupling agent: propyltriethoxysilane isocyanate, Xingdongcheng Chemical; Lubricant: LOXIOL G32, from Imeil, Germany.

[0026] Preparation method of polyamide composition in examples and comparative examples: According to the formula, the components are mixed evenly and granulated by extrusion through a twin-screw extruder to obtain a polyamide composition, wherein the barrel temperature range is 180-320℃ and the rotation speed range is 400 rpm.

[0027] Test methods: (1) Weld line strength: The polyamide composition is injected from both sides simultaneously and molded into an ISO tensile test specimen. The weld line is located in the middle of the tensile test specimen. After the test specimen is conditioned for 24 hours in a laboratory standard environment of 23°C and 50%RH, the weld line strength is tested according to the ISO-527-2:2012 standard.

[0028] (2) Gloss test: The above 20mm×20mm×2.5mm square plate was used for testing. Ten points were randomly tested and the average value was taken. BYK gloss meter, measuring angle 60°.

[0029] Table 1: Content of each component and test results of the polyamide compositions in Examples 1-7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PA66 70 PA6 75 75 75 75 PA10T 80 PA1010 70 Wollastonite A 10 20 Wollastonite B 13 17 13 13 13 Kaolin A 15 18 12 18 18 18 Kaolin B 16 Hyperbranched polyester A 0.8 0.5 1.7 3 0.5 0.5 Hyperbranched polyester B 0.5 Epoxysilane coupling agent 1.2 0.8 3 2.1 0.8 aminosilane coupling agents 0.8 Isocyanate silane coupling agent 0.8 lubricant 0.5 Fusion line strength 82 80 78 75 80 79 83 Surface gloss 90 87 83 92 89 89 90 Table 2: Content of each component and test results of the polyamide compositions in Examples 8-14 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 PA6 75 75 75 75 75 75 75 Wollastonite B 13 13 13 13 13 13 13 Kaolin A 18 18 18 18 18 18 18 Hyperbranched polyester types C D E F G H I Hyperbranched polyester content 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Epoxysilane coupling agent 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Fusion line strength 84 82 81 85 87 83 86 Surface gloss 91 89 87 92 94 91 94 As can be seen from Examples 2 / 7-14, for similar molecular weights, end-carboxyl hyperbranched polyesters are superior to end-hydroxyl hyperbranched polyesters; at the same time, the preferred molecular weight range of hyperbranched polyesters is 1100-3000; as can be seen from Examples 12 / 14 and Examples 2 / 10, the technical effects of the two sets of examples are similar, indicating that the influence of hyperbranched polyesters on the polyamide composition of the present invention is mainly in molecular weight, and the influence of the main chain structure is not obvious.

[0030] Table 3: Content of each component and test results of comparative polyamide compositions Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 PA6 75 75 75 75 75 75 75 75 Wollastonite B 13 31 5 26 13 13 Kaolin A 31 26 5 18 18 mica powder 18 31 Hyperbranched polyester types A A A A A A A Hyperbranched polyester content 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Epoxysilane coupling agent 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Fusion line strength 73 74 65 58 68 76 70 67 Surface gloss 65 73 79 63 82 75 65 78 As can be seen from the above examples and comparative examples, the weld line strength of the polyamide composition of the present invention is greater than 70 MPa; the surface gloss is greater than 80 Gu.

[0031] As shown in Comparative Example 1, when mica powder is used instead of kaolin, the weld line strength decreases significantly, and the surface gloss decreases severely.

[0032] As can be seen from Comparative Examples 2 / 3 / 4, it is impossible to achieve the technical effects of high weld line strength and high surface gloss simultaneously by using wollastonite, kaolin, and mica powder alone.

[0033] As can be seen from Comparative Examples 5 / 6, when the amounts of wollastonite and kaolin are outside the scope of this invention, it is also impossible to simultaneously achieve the technical effects of high weld line strength and high surface gloss.

[0034] As shown in Comparative Example 7, the weld line strength and surface gloss are very poor when there is no hyperbranched polyester, especially the surface gloss is severely reduced.

[0035] As shown in Comparative Example 8, the weld line strength and surface gloss are very poor when there is no silane coupling agent.

Claims

1. A polyamide composition, characterized in that, By weight, it includes the following components: 70-80 parts of polyamide; 10-20 parts of wollastonite; 10-20 parts of kaolin; 0.3-3 parts of hyperbranched polyester; 0.3-3 parts of silane coupling agent.

2. The polyamide composition according to claim 1, characterized in that, The weight-average molecular weight of the hyperbranched polyester is in the range of 500-6500 g / mol, and the end groups are at least one of terminal carboxyl groups and terminal hydroxyl groups.

3. The polyamide composition according to claim 2, characterized in that, The weight-average molecular weight of the hyperbranched polyester is in the range of 1100-3000 g / mol; the end groups are terminal carboxyl groups.

4. The polyamide composition according to claim 1, characterized in that, The mesh size of the wollastonite and kaolin is 500-1500 mesh.

5. The polyamide composition according to claim 1, characterized in that, The silane coupling agent is selected from at least one of epoxy silane coupling agents, amino silane coupling agents, and isocyanate silane coupling agents.

6. The polyamide composition according to claim 1, characterized in that, The relative viscosity range of the polyamide is 1.6-3.

3.

7. The polyamide composition according to claim 1, characterized in that, The polyamide resin is selected from at least one of aliphatic polyamide resin and semi-aromatic polyamide resin; the aliphatic polyamide resin is selected from at least one of PA66, PA46, PA610, PA612, PA56, PA510, PA512, PA910, PA912, PA913, PA914, PA915, PA616, PA936, PA1010, PA1012, PA1013, PA1014, PA1210, PA1212, PA1213, PA1214, PA614, PA613, PA615, PA616, PA5, PA6, PA11, PA12; the semi-aromatic polyamide is selected from at least one of PA MXD6, PA10T, PA10T1010, PA10T66, PA6T, PA6T66, PA9T.

8. The polyamide composition according to claim 1, characterized in that, The product also includes 0-2 parts by weight of an auxiliary agent, wherein the auxiliary agent is selected from at least one of antioxidants and UV stabilizers.

9. A method for preparing the polyamide composition according to any one of claims 1-8, characterized in that, According to the formula, the components are mixed evenly and then extruded and granulated through a twin-screw extruder to obtain a polyamide composition. The barrel temperature range is 180-320℃ and the rotation speed range is 200-700 rpm.

10. The use of the polyamide composition according to any one of claims 1-8, characterized in that, Used for injection molding of parts for consumer electronics, rail transportation, power tools, shared bicycles, or water treatment equipment.