Polyamide composition and preparation method thereof

Abstract

The invention discloses a polyamide composition and a preparation method thereof, and belongs to the field of high polymer materials. The method comprises the following steps: uniformly mixing the polyamide resin, the flexibilizer, the coupling agent, the antioxidant and the lubricant, and adding the mixture into a double-screw extruder from a main feeding hopper; adding the hollow glass beads into a double-screw extruder from a side feeding hopper close to a main feeder, and adding glass fibers into the double-screw extruder from a side feeding hopper close to a machine head; the polyamide composition is prepared through melt blending, extrusion granulation, homogenization and drying; by adjusting the blanking sequence of the hollow glass beads and the conventional glass fibers, controlling the rotating speed of a screw rod and the feeding of an extruder, firstly combining the hollow glass beads with matrix resin containing a compatilizer and then adding the glass fibers, the shearing force borne by the hollow glass beads in the resin is reduced, and the glass fibers are uniformly dispersed in the matrix resin. The retention rate of the hollow glass beads in the polyamide is improved, so that the purpose of remarkably reducing the density of the material is achieved.

Description

Technical Field

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

[0002] Polyamide (commonly known as nylon, abbreviated as PA) refers to a class of polymer materials containing polar amide groups (-NH-CO-) on their polymer chains. It is the engineering material with the most varieties, the largest output, the widest application, and the best comprehensive performance among the five major general-purpose engineering plastics. Due to its superior comprehensive properties such as mechanical properties, heat resistance, wear resistance, and chemical resistance, it is widely used in automobiles, power tools, electronics, aerospace and other fields.

[0003] With societal development, engineering materials face increasingly demanding operating environments and higher performance requirements, often necessitating low density, high strength, and good toughness simultaneously. To meet this demand, recent modifications to nylon materials have primarily involved adding glass fibers, toughening agents, and low-density hollow glass microspheres for reinforcement and toughening. The addition of glass fibers significantly improves the tensile strength, flexural strength, and modulus of the material; the addition of toughening agents increases toughness while reducing density; and the addition of hollow glass microspheres significantly reduces density while increasing strength. However, typically, the addition of toughening agents and hollow glass microspheres leads to a corresponding decrease in the tensile and flexural strength of glass fiber-reinforced materials, resulting in a tradeoff between achieving both rigidity and toughness. Therefore, this paper proposes a polyamide composition and its preparation method. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a polyamide composition and its preparation method, thereby solving the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a polyamide composition includes the following steps:

[0007] After the polyamide resin, toughening agent, coupling agent, antioxidant and lubricant are mixed evenly, they are fed into the twin-screw extruder from the main feed hopper;

[0008] Hollow glass microspheres are fed into a twin-screw extruder from the side feed hopper closest to the main feed, and glass fibers are fed into the twin-screw extruder from the side feed hopper closest to the die head; after melt blending, extrusion granulation, homogenization and drying, a polyamide composition is obtained.

[0009] Furthermore, the following raw materials in parts by weight are used to prepare the polyamide composition:

[0010]

[0011] Further, the polyamide resin is one of PA6, PA66, PA610, PA612, PA1010, PA1012, PA11, PA12, PA1212, and MXD6.

[0012] Further, the toughening agent is: maleic anhydride-grafted EPDM rubber or maleic anhydride-grafted polyolefin elastomer; the grafting rate of maleic anhydride in the toughening agent is 0.5% to 1.5%.

[0013] Furthermore, the coupling agent is a silane coupling agent, which includes one or more combinations of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0014] Furthermore, the antioxidant includes at least one of hindered phenolic antioxidants, thioether antioxidants, and phosphite antioxidants;

[0015] The hindered phenolic antioxidants include at least one of antioxidant 1098 and antioxidant 1010; the thioether antioxidants include at least one of antioxidant DSTP and antioxidant DLTP; and the phosphite antioxidants include at least one of antioxidant 168 and antioxidant PEP-36.

[0016] Furthermore, the lubricant is at least one of ethylene bis-stearamide, zinc stearate, modified polyethylene wax, silicone masterbatch, and pentaerythritol stearate.

[0017] Furthermore, the twin-screw extruder has a processing temperature of 210–280°C, a screw speed of 250–350 rpm, and a screw length-to-diameter ratio of (36–44):1.

[0018] A polyamide composition was prepared using the above-described preparation method.

[0019] The above-mentioned polyamide composition is used as a raw material in the preparation of consumer electronics products.

[0020] The beneficial effects of this invention are:

[0021] This invention adjusts the feeding sequence of hollow glass microspheres and conventional glass fibers, allowing the hollow glass microspheres to bond with a matrix resin containing a compatibilizer before adding the glass fibers. This reduces the shear force on the hollow glass microspheres in the resin and increases their retention rate in the polyamide, thus significantly reducing the material density. Furthermore, this feeding method, where the glass fibers are fed closer to the extruder head, increases their retention length in the matrix resin, resulting in a substantial increase in material strength. The combined effect of these two side-feeding methods results in a polyamide composition with low density while maintaining good strength and high rigidity. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] A polyamide composition comprising the following raw materials in parts by weight:

[0024]

[0025] The polyamide resin is one of the following: PA6, PA66, PA610, PA612, PA1010, PA1012, PA11, PA12, PA1212, and MXD6.

[0026] The toughening agent is maleic anhydride-grafted EPDM rubber or maleic anhydride-grafted polyolefin elastomer; the grafting rate of maleic anhydride in the toughening agent is 0.5% to 1.5%, more preferably, the grafting rate of maleic anhydride in the toughening agent is 0.5% to 1.0%. The present invention further limits the maleic anhydride grafting rate, thereby further toughening the polyamide composition of the present invention while maintaining excellent mechanical strength.

[0027] The density of the hollow glass microspheres is 0.46 g / cm³, and the pressure of 90% residual weight is greater than 16,000 Psi.

[0028] The glass fiber has a density of 2.70 g / cm³, a length of 3 mm, and a precursor fiber diameter of 10 μm.

[0029] The coupling agent is a silane coupling agent, which may be one of the following: γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), γ-methacryloyloxypropyltrimethoxysilane (KH570), etc., or a combination of several of the above silane coupling agents. It is understood that the above silane coupling agents are merely examples, and silane coupling agents well known to those skilled in the art are applicable to the technical solutions of this invention.

[0030] The antioxidant is at least one of hindered phenolic antioxidants, thioether antioxidants, and phosphite antioxidants; the hindered phenolic antioxidant may be at least one of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098) or pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010); the thioether antioxidant may be at least one of distearate thiodipropionate (antioxidant DSTP) or dilaurate thiodipropionate (antioxidant DLTP); the phosphite antioxidant may be at least one of tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168) or pentaerythritol diphosphate bis(2,6-di-tert-butyl-4-methylphenyl) (antioxidant PEP-36). It is understood that the above is only used as an example of antioxidants to make the technical solution of the present invention clearer, and is not intended to limit the scope of protection of the present invention.

[0031] The lubricant is at least one of ethylene bis-stearamide, zinc stearate, modified polyethylene wax, silicone masterbatch, and pentaerythritol stearate.

[0032] The preparation method of the above polyamide composition includes the following steps:

[0033] According to the formula, polyamide resin, toughening agent, coupling agent, antioxidant and lubricant are weighed and mixed evenly at high speed. The mixture is then fed into the twin-screw extruder from the main feed hopper. At the same time, hollow glass microspheres are fed into the twin-screw extruder from the side feed hopper closest to the main feed. Glass fiber is fed into the twin-screw extruder from the side feed hopper closest to the die head. After melt blending, extrusion granulation, homogenization and drying, a polyamide composition is obtained.

[0034] The twin-screw extruder has a processing temperature of 210–280℃, a screw speed of 250–350 rpm, and a screw length-to-diameter ratio of 36–44:1.

[0035] The technical solution of the present invention will be described in detail below through the following embodiments; all parts in the embodiments are parts by weight; the sources of raw materials in the embodiments are as follows:

[0036] PA612, Shandong Dongchen Type II;

[0037] Maleic anhydride-grafted polyolefin elastomer, Coase W1A;

[0038] Antioxidant 1098, Tianjin Lianlong New Material Co., Ltd.

[0039] Silane coupling agent (FD-550), Foshan Boiling Point Chemical Co., Ltd. FD-550

[0040] Zinc stearate lubricant, Dongguan Hanwei New Material Technology Co., Ltd. AV300

[0041] Hollow glass microspheres, 3M IM16K (USA)

[0042] Glass fiber, chopped glass fiber ECS10-03-568H from China Jushi Co., Ltd.

[0043] Example 1

[0044] According to the weight proportions, 61 parts of dried PA612, 5 parts of maleic anhydride grafted polyolefin elastomer, 0.2 parts of antioxidant 1098, 0.5 parts of silane coupling agent, and 0.3 parts of lubricant zinc stearate were added to a high-speed mixer and mixed at high speed for 10 minutes. Then, the mixture was fed into a twin-screw extruder through the main feed hopper. Next, 26 parts of dried hollow glass microspheres were added into the twin-screw extruder through the side feed hopper closest to the main feed port. 7 parts of dried glass fiber were added into the twin-screw extruder (temperature 230℃, screw speed 280 rpm, screw length-to-diameter ratio 36:1) through the side feed port closest to the extruder die head. After melt blending, extrusion granulation, homogenization, and drying, a polyamide composition was obtained.

[0045] Example 2

[0046] According to the weight proportions, 61 parts of dried PA612, 5 parts of maleic anhydride grafted polyolefin elastomer, 0.2 parts of antioxidant 1098, 0.5 parts of silane coupling agent, and 0.3 parts of lubricant zinc stearate were added to a high-speed mixer and mixed at high speed for 10 minutes. Then, the mixture was fed into a twin-screw extruder through the main feed hopper. Next, 21 parts of dried hollow glass microspheres were added into the twin-screw extruder through the side feed hopper closest to the main feed port. 12 parts of dried glass fiber were added into the extruder through the side feed port closest to the extruder head (temperature 230℃, screw speed 280 rpm, screw length-to-diameter ratio 36:1). After melt blending, extrusion granulation, homogenization, and drying, a polyamide composition was obtained.

[0047] Example 3

[0048] According to the weight proportions, 59 parts of dried PA612, 5 parts of maleic anhydride grafted polyolefin elastomer, 0.2 parts of antioxidant 1098, 0.5 parts of silane coupling agent, and 0.3 parts of lubricant zinc stearate were added to a high-speed mixer and mixed at high speed for 10 minutes. Then, the mixture was fed into a twin-screw extruder through the main feed hopper. Next, 25 parts of dried hollow glass microspheres were added into the twin-screw extruder through the side feed hopper closest to the main feed port. Finally, 10 parts of dried glass fiber were added into the extruder through the side feed port closest to the extruder die head (temperature 230℃, screw speed 280 rpm, screw length-to-diameter ratio 36:1). After melt blending, extrusion granulation, homogenization, and drying, a polyamide composition was obtained.

[0049] Comparative Example 1

[0050] In this comparative example, the feeding order of hollow glass microspheres and glass fibers in Example 1 was changed. The amount of other components added and the feeding order remained unchanged, and the process was not adjusted in any way.

[0051] Comparative Example 2

[0052] In this comparative example, the feeding order of hollow glass microspheres and glass fibers in Example 3 was changed. The amount of other components added and the feeding order remained unchanged, and the process was not adjusted in any way.

[0053] Comparative Example 3

[0054] In this comparative example, the coupling agent in Example 3 was removed, and a smaller proportion was replaced with polyamide PA612. The amounts of other components added and the order of feeding remained unchanged, and the process was not adjusted in any way.

[0055] The polyamide composition particles from Examples 1-3 and Comparative Examples 1-2 were prepared into test strips and compared according to the corresponding international standards. The density was tested according to ISO 1183-1, the tensile strength was tested according to ISO 527 at a tensile speed of 50 mm / min, the flexural strength and flexural modulus were tested according to ISO 178 at a flexural rate of 2 mm / min, and the impact strength was tested according to ISO 179. The test results are shown in Table 1.

[0056] Table 1 Performance test data of Examples 1-3 and Comparative Examples 1-3

[0057]

[0058] Based on the test results in the table above, it can be seen that:

[0059] 1) In Comparative Example 2, glass fibers were added from the side feeder near the main feed port and hollow glass microspheres were added from the side feeder near the die head. In Example 3, hollow glass microspheres and glass fibers were added from the side feeder near the main feed port to the twin-screw extruder. The composite material in Comparative Example 2 had a significantly higher density and poorer overall mechanical properties.

[0060] 2) The same applies to Comparative Example 1 and Example 1. This indicates that when multiple side feeders are present in the polyamide component, the order in which the side feeder pairs are added has a significant impact on the overall material properties. When glass fibers are added to the system first, the shear force they experience is relatively large, resulting in a short retention length in the material. The final result is a mediocre reinforcing effect. However, when hollow glass microspheres are added to the system first, due to the control of screw speed and formulation, a higher retention rate is achieved. This not only significantly reduces the overall density of the material but also improves its strength, achieving a balance between rigidity and toughness.

[0061] 3) Using the system without coupling agent in Comparative Example 3, compared with Example 3, the system without coupling agent has a significantly higher density and slightly higher strength than Comparative Example 2, but is lower overall than Example 3. This indicates that the coupling agent has a certain lubricating effect in the system, which can greatly improve the retention rate of hollow glass microspheres, so as to reduce the material density and achieve the purpose of achieving a balance between rigidity and toughness.

[0062] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a polyamide composition, characterized in that, Includes the following steps: After the polyamide resin, toughening agent, coupling agent, antioxidant and lubricant are mixed evenly, they are fed into the twin-screw extruder from the main feed hopper; Hollow glass microspheres are fed into a twin-screw extruder from the side feed hopper closest to the main feed, and glass fibers are fed into the twin-screw extruder from the side feed hopper closest to the die head; after melt blending, extrusion granulation, homogenization and drying, a polyamide composition is obtained.

2. The method for preparing a polyamide composition according to claim 1, characterized in that, The following raw materials were used in the preparation of the polyamide composition:

3. The method for preparing a polyamide composition according to claim 1, characterized in that, The polyamide resin is one of PA6, PA66, PA610, PA612, PA1010, PA1012, PA11, PA12, PA1212, and MXD6.

4. The method for preparing a polyamide composition according to claim 1, characterized in that, The toughening agent is: maleic anhydride-grafted EPDM rubber or maleic anhydride-grafted polyolefin elastomer; the grafting rate of maleic anhydride in the toughening agent is 0.5% to 1.5%.

5. The method for preparing a polyamide composition according to claim 1, characterized in that, The coupling agent is a silane coupling agent, which includes one or more combinations of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

6. The method for preparing a polyamide composition according to claim 1, characterized in that, The antioxidants include at least one of hindered phenolic antioxidants, thioether antioxidants, and phosphite antioxidants; The hindered phenolic antioxidants include at least one of antioxidant 1098 and antioxidant 1010; the thioether antioxidants include at least one of antioxidant DSTP and antioxidant DLTP; and the phosphite antioxidants include at least one of antioxidant 168 and antioxidant PEP-36.

7. The method for preparing a polyamide composition according to claim 1, characterized in that, The lubricant is at least one of ethylene bis-stearamide, zinc stearate, modified polyethylene wax, silicone masterbatch, and pentaerythritol stearate.

8. The method for preparing a polyamide composition according to claim 1, characterized in that, The twin-screw extruder has a processing temperature of 210–280℃, a screw speed of 250–350 rpm, and a screw length-to-diameter ratio of (36–44):

1.

9. A polyamide composition, characterized in that, It was prepared using the preparation method described in any one of claims 1-8.

10. The use of the polyamide composition of claim 9 as a raw material in the preparation of consumer electronics products.

Images