CN101230195B - A kind of nylon composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a nylon composite material and a preparation method thereof. The material is composed of nylon 66 slices, thermotropic liquid crystal polymer, needle-like mineral fiber, coupling agent, and antioxidant. The weight ratio of nylon 66 chips, thermotropic liquid crystal polymer, acicular mineral fiber, coupling agent and antioxidant is 60-70:10-15:20-30:4.5:0.5. The preparation method is to mix nylon 66 slices with a weight ratio of 60-70:10-15:20-30:4.5:0.5, thermotropic liquid crystal polymer, needle-like mineral fiber, glass fiber, coupling agent and antioxidant in the Mix evenly under stirring conditions, then extrude at 280°C or 295°C, draw, pelletize, and inject into samples to obtain nylon system composite materials. The nylon system of the present invention can achieve a significant reinforcing effect with a small amount of thermotropic liquid crystal, and can reduce product warpage, reduce product surface roughness, and reduce cost.

Description

A kind of nylon composite material and preparation method thereof

technical field

The invention relates to a nylon composite material, in particular to a nylon composite material containing thermotropic liquid crystal polymer and acicular mineral filler and a preparation method thereof.

Background technique

Thermotropic liquid crystal polymers appear in a liquid crystal state because heating destroys the crystalline structure of polymer segments and makes the amorphous structure enter a molten state and form a certain orderly arrangement. It is a new type of high-performance polymer material, which is characterized by high modulus, high strength, unique fluidity in the liquid crystal state, excellent thermal stability, chemical resistance and weather resistance, and excellent Excellent comprehensive properties such as solvent resistance, low linear expansion coefficient and density. Utilizing the characteristics of thermotropic liquid crystal polymers, blending and modifying them with thermoplastic engineering plastics can improve the performance of thermoplastic engineering plastics. In the thermotropic liquid crystal polymer-thermoplastic engineering plastics blend modification system, the thermotropic liquid crystal polymer has three obvious effects: ①The role of the reinforcing agent, the formed microfibrillated surface and aspect ratio are higher than those of ordinary reinforcing fibers, so The enhancement effect is very significant; ②The role of the processing flow modifier can reduce the viscosity of the blend melt, improve the fluidity and molding processing performance of difficult-to-process thermoplastics; ③Save the energy consumption of molding processing.

In the modification of nylon 66, the use of thermotropic liquid crystal polymers can significantly improve the comprehensive mechanical properties, but the enhancement effect is far from the theoretical calculation. Fibrous arrangement. To this end, a composite material was developed, so that the thermotropic liquid crystal polymer can be better fiberized in the nylon resin, so as to obtain a good reinforcement effect, reduce the amount of thermotropic liquid crystal, and reduce the cost. It is meaningful to make nylon products reinforced by thermotropic liquid crystal polymers acceptable in the market and put into practical application as soon as possible.

Acicular mineral filler is a kind of natural mineral or man-made mineral fiber with high aspect ratio. The aspect ratio is above 20:1. It has been reported as a filler to modify thermoplastic engineering plastics. It has the following advantages: ① Reinforcement can greatly enhance the mechanical properties of the matrix resin. ② Good thermal stability, low thermal deformation, and good dimensional stability of the product, all of which are better than the glass fiber filler that is also often used in nylon. ③The surface gloss of the product is higher than that of glass fiber filling, and the wear and tear on the processing machinery during processing is small. ④ It can reduce the warpage of the product, improve the heat resistance of the product, and reduce the hygroscopicity of the nylon product. There is no report on combining it with thermotropic liquid crystal polymer to improve the fiber-forming status of thermotropic liquid crystal polymer in nylon resin. The needle-shaped mineral filler can interact with the thermotropic liquid crystal polymer to produce a synergistic effect, improve the fiber-forming effect of the thermotropic liquid crystal polymer, and greatly improve the comprehensive performance of the composite material.

Chinese patent 03126409.3 discloses a composite material containing particle fillers and thermotropic liquid crystal polymers. Its preparation method is to blend and modify particle fillers such as hollow glass microspheres and main chain all-aromatic liquid crystal polymers, and heat them at 260-280 ° C. Down-extrusion granulation; thereby obtaining a composite material with good dimensional stability, which can be used to make plastic parts with fine structure.

Chinese patent CN1168395A discloses mixing and modifying liquid crystal polymer and oxidized polyarylene sulfide to prepare a material with excellent abrasion resistance, which can be used to manufacture gears, racks, bearings and other components.

Chinese patent CN1454934 discloses a polyamide 66 composite material co-filled with montmorillonite and wollastonite and a preparation method thereof. This composite material has high modulus and good temperature resistance, while reducing cost. However, the processing is more difficult, and the wear and tear on the processing machine is more serious.

But none of the above three patents is used to prepare nylon composites containing thermotropic liquid crystal polymers and needle-shaped mineral fibers. If the nylon composite material of the present invention is prepared directly by referring to the above-mentioned patent, the direct compatibility problem of each component cannot be solved, which will lead to phase separation, and the performance of the composite material will be significantly reduced.

Contents of the invention

The purpose of the present invention is to provide a nylon composite material with practical application value prepared by utilizing the excellent properties of thermotropic liquid crystal polymers, the good reinforcing properties of acicular mineral fillers and low price.

The purpose of the present invention can be achieved through the following technical solutions.

The nylon composite material containing thermotropic liquid crystal polymer and acicular mineral fiber of the present invention is composed of nylon 66 slices, thermotropic liquid crystal polymer, acicular mineral fiber, coupling agent and antioxidant. The weight ratio is 60～70:10～15:15～25:4.5:0.5

The nylon 66 slices are engineering plastic grade nylon 66 slices.

The thermotropic liquid crystal polymer is a Vectra A type thermotropic liquid crystal polymer produced by Goodfellow Company of the United States or a Zenite type thermotropic liquid crystal polymer produced by Dupont Company of the United States.

The acicular mineral fiber is carbon fiber, halloysite nanotube, acicular wollastonite, Kevlar fiber or whisker.

Described coupling agent is the A-1100 type coupling agent that U.S. Union Carbon Company produces, the Fusabond type coupling agent of U.S. Dupont Company, the EPON type coupling agent of U.S. Aldrich Company, or the Ma To anhydride, styrene copolymer coupling agent.

The antioxidant is the Lunchemao-R type hindered phenol antioxidant produced by the Great Lakes Company of the United States.

The preparation method of the nylon composite material containing thermotropic liquid crystal polymer and acicular mineral fiber of the present invention mainly contains the following steps:

(1) Nylon 66 slices with a weight ratio of 60～70:10～15:20～30:4.5:0.5, thermotropic liquid crystal polymer, needle-like mineral fiber, coupling agent, antioxidant under stirring conditions well mixed;

(2) Extrude at 280° C. or 295° C., draw, pelletize, and inject into samples to obtain ternary nylon composite materials.

The present invention utilizes the coupling agent to improve the compatibility between the thermotropic liquid crystal polymer and the nylon 66 resin, the compatibility between the acicular mineral filler and the nylon 66 resin, reduces the phase separation between each component, and improves each component. The interfacial strength between the components improves the tensile strength, flexural strength, flexural modulus and other mechanical properties of the composite material, and makes the shape of the product uniform and improves the dimensional stability. The nylon 66 composite material prepared by the invention can be used to manufacture various plastic parts.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The thermotropic liquid crystal polymer in the nylon composite material composition of the present invention forms a microfiber structure in the nylon 66 resin matrix during extrusion with nylon 66 slices, thereby reducing the melt viscosity of the nylon 66 resin and improving the melt viscosity. Bulk flow rate, thereby improving processing performance;

(2) The addition of acicular mineral fillers has played a multiple role in improvement. Compared with commonly used filler glass fibers, it has the following advantages: ①The fluidity of acicular mineral fillers is better than that of glass fiber fillers. ②Acicular mineral filler has good thermal stability, low thermal deformation, and better dimensional stability than glass fiber. ③The surface gloss is higher than that of glass fiber filling. ④Acicular mineral fillers can solve the problem of floating fibers on the surface and easy warping of products caused by glass fiber fillers. ⑤The microcapillaries are easy to form between the needle-like mineral fillers, which can promote the fiber formation of thermotropic liquid crystal polymers.

(3) The addition of the coupling agent not only improves the compatibility between the thermotropic liquid crystal polymer and the nylon 66 matrix resin, but also improves the compatibility between the acicular mineral fiber and the matrix resin, as well as the acicular mineral fiber and the thermotropic liquid crystal polymer. compatibility between. These are all beneficial to form a uniformly dispersed phase structure and avoid phase separation, so that the prepared composite material can fully demonstrate the excellent comprehensive performance of thermotropic liquid crystals.

(4) The addition of antioxidants can avoid oxidative degradation of materials during processing and the resulting performance degradation.

Detailed ways

In order to better understand the technical characteristics of the present invention, the present invention will be further described below in conjunction with the examples. It should be noted that the examples are not limiting the protection scope of the present invention.

Example 1

In parts by weight, weigh 60 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 10 parts of Vectra A type thermotropic liquid crystal polymer (produced by Goodfellow Company in the United States), 25 parts of needle-shaped Wollastonite (produced by Nanfang Wollastonite Industrial Company, Xinyu City, Jiangxi), 4.5 parts of maleic anhydride and styrene copolymer type coupling agent (produced by Shanghai Shibida Company), 0.5 part of Lunchemao-R hindered phenol antioxidant (produced by Great Lakes Corporation of the United States); under stirring conditions, mix the above components evenly, then extrude, draw, and granulate the resulting mixture in an extruder at 290 ° C, and make samples by injection molding, and perform performance test. The mechanical properties of the sample were tested according to the following standards. The results are shown in Table 1. It can be seen from the table that compared with pure nylon 66, the tensile strength increased by 13%, the flexural strength increased by 3%, the flexural modulus was basically the same, and the notched impact strength increased. 25%, the heat distortion temperature increased by 40°C. Overall performance has been improved. I think this improvement is mainly due to the mutual reinforcement of fillers and liquid crystal resins. With the help of needle-like minerals, liquid crystals are well oriented and formed into fibers, which greatly improves the mechanical properties of the material. With the increase of the amount of liquid crystal and filler, the improvement of this performance becomes more and more remarkable.

Table 1

5. Izod notched impact strength (J/m) 50   ASTM D256 6. Heat distortion temperature (°C, 1.82MPa) 220   ASTM D648 7. Specific gravity (g/cm3) 1.6  ASTM D792

Example 2

In parts by weight, weigh 70 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 10 parts of Zenite type thermotropic liquid crystal polymers (produced by U.S. Dupont Company), 15 parts of acicular silicon Limestone (produced by Nanfang Wollastonite Industrial Company, Xinyu City, Jiangxi Province), 4.5 parts of maleic anhydride and styrene copolymer type coupling agent (produced by Shanghai Shibida Company), 0.5 part of Lunchemao-R hindered phenol antioxidant ( Produced by the Great Lakes Company of the United States); under stirring conditions, the above-mentioned components are mixed uniformly, and then the resulting mixture is extruded, drawn, and granulated in an extruder at 285 ° C, and injected into samples for performance testing . The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 2: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 18%, the flexural strength increased by 3%, the flexural modulus increased by 30%, and the notched impact strength Increased by 75%, heat distortion temperature increased by 10°C. Comprehensive performance has been greatly improved.

Table 2

Example 3

In parts by weight, weigh 60 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 10 parts of Vectra A type thermotropic liquid crystal polymer (produced by Goodfellow Company in the United States), 25 parts of needle-shaped Wollastonite (produced by Southern Wollastonite Industrial Company, Xinyu City, Jiangxi Province), 4.5 parts of EPON coupling agent (produced by Aldrich Company of the United States), 0.5 part of Lunchemao-R type hindered phenol antioxidant (produced by Great Lakes Company of the United States); under stirring conditions The above components were mixed uniformly, and then the resulting mixture was extruded, drawn, pelletized in an extruder at 290°C, and injected into samples for performance testing. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 3: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 18%, the flexural strength increased by 10%, the flexural modulus increased by 20%, and the notched impact strength Increased by 50%, heat distortion temperature increased by 40°C. Comprehensive performance has been greatly improved.

table 3

Example 4

In parts by weight, 70 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 10 parts of Vectra A-type thermotropic liquid crystal polymer (produced by Goodfellow, U.S.), 15 parts of Ello Stone nanotube (self-made), 4.5 parts of A-1100 type coupling agent (produced by U.S. Union Carbide), 0.5 part of Lunchemao-R type hindered phenol antioxidant (produced by U.S. Great Lakes); The mixture was uniformly mixed, and then the obtained mixture was extruded in an extruder at 285°C, drawn, granulated, and injected into samples for performance testing. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 4: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 25%, the flexural strength increased by 6%, the flexural modulus increased by 50%, and the notched impact strength Increased by 100%, the heat distortion temperature increased by 20°C. Comprehensive performance has been greatly improved.

Table 4

Example 5

In parts by weight, weigh 65 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 15 parts of Zenite type thermotropic liquid crystal polymers (produced by Dupont Corporation of the United States), 15 parts of acicular silicon Limestone (produced by Southern Wollastonite Industrial Company, Xinyu City, Jiangxi Province), EPON coupling agent (produced by Aldrich Company of the United States), 0.5 part of Lunchemao-R type hindered phenol antioxidant (produced by Great Lakes Company of the United States); The above components were mixed evenly, and then the obtained mixture was extruded, drawn, pelletized in an extruder at 285° C., and injected into samples for performance testing. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 5: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 25%, the flexural strength did not increase, the flexural modulus increased by 50%, and the notched impact strength Increased by 87%, heat distortion temperature increased by 15 ℃. Comprehensive performance has been greatly improved.

table 5

1. Tensile strength (MPa) 100 ASTM D638 2. Elongation at break (%) 3.1 ASTM D638 3. Bending strength (MPa) 125 ASTM D790 4. Flexural modulus (MPa) 45000 ASTM D790 5. Izod notched impact strength (J/m) 75 ASTM D256 6. Heat distortion temperature (°C, 1.82MPa) 195 ASTM D648 7. Specific gravity (g/cm3) 1.60 ASTM D792

Example 6

In parts by weight, weigh 60 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 20 parts of Vectra A-type thermotropic liquid crystal polymers (produced by Goodfellow Company in the United States), 15 parts of needle-shaped Wollastonite (produced by Nanfang Wollastonite Industrial Company, Xinyu City, Jiangxi), 4.5 parts of maleic anhydride and styrene copolymer type coupling agent (produced by Shanghai Shibida Company), 0.5 part of Lunchemao-R hindered phenol antioxidant (produced by Great Lakes Corporation of the United States); under stirring conditions, mix the above components evenly, then extrude, draw, and granulate the resulting mixture in an extruder at 290 ° C, and make samples by injection molding, and perform performance test. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 6: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 37.5%, the flexural strength increased by 18%, the flexural modulus increased by 30%, and the notched impact strength Increased by 75%, heat distortion temperature increased by 45°C. Comprehensive performance has been greatly improved.

Table 6

6. Heat distortion temperature (°C, 1.82MPa) 225 ASTM D648 7. Specific gravity (g/cm3) 1.65 ASTM D792

Example 7

In parts by weight, weigh 60 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 20 parts of Zenite type thermotropic liquid crystal polymers (produced by U.S. Dupont), 15 parts of halloysite Nanotube (self-made), 4.5 parts of maleic anhydride and styrene copolymer type coupling agent (produced by Shanghai Shibida Co., Ltd.), 0.5 part of Lunchemao-R type hindered phenol antioxidant (produced by U.S. Great Lakes Company); under stirring conditions The above components were mixed uniformly, and then the resulting mixture was extruded, drawn, pelletized in an extruder at 285°C, and injected into samples for performance testing. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 7: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 37.5%, the flexural strength increased by 3%, the flexural modulus increased by 60%, and the notched impact The strength is increased by 105%, and the heat distortion temperature is increased by 20°C. Comprehensive performance has been greatly improved.

Table 7

Example 8

In parts by weight, 60 parts of nylon 66 slices (engineering plastic grade nylon 66 slices produced by China Shenma Group Co., Ltd.), 20 parts of Vectra A type thermotropic liquid crystal polymers (produced by U.S. Goodfellow Company), 15 parts of angstrom Rockstone nanotubes (self-made), 4.5 parts of EPON coupling agent (produced by Aldrich Company of the United States), 0.5 part of Lunchemao-R type hindered phenol antioxidant (produced by Great Lakes Company of the United States); under stirring conditions, mix the above components evenly , and then the resulting mixture was extruded in an extruder at 285°C, drawn, pelletized, and injected into samples for performance testing. The mechanical properties of the sample were tested according to the following standards, and the results are shown in Table 8: As can be seen from the table, compared with pure nylon 66, the tensile strength increased by 50%, the flexural strength increased by 18.1%, the flexural modulus increased by 83.3%, and the notched impact The strength is increased by 125%, and the heat distortion temperature is increased by 40°C. Comprehensive performance has been greatly improved.

Table 8

Claims (6)

1. A nylon composite material is characterized in that the nylon composite material is made up of nylon 66 slices, thermotropic liquid crystal polymer, acicular mineral fiber, coupling agent, antioxidant; Nylon 66 slices, thermotropic liquid crystal polymer, needle The weight ratio of shape mineral fiber, coupling agent and antioxidant is 60:10:30:4.5:0.5; Wherein, the thermotropic liquid crystal polymer is a Vectra type thermotropic liquid crystal polymer or a Zenite type thermotropic liquid crystal polymer. 2. The nylon composite material according to claim 1, characterized in that the nylon 66 slices are engineering plastic grade nylon 66 slices. 3. The nylon composite material according to claim 1, characterized in that the acicular mineral fibers are carbon fibers, halloysite nanotubes, acicular wollastonite, Kevlar fibers or whiskers. 4. The nylon composite material according to claim 1, characterized in that the coupling agent is a silane type coupling agent, an ethylene-acrylic acid copolymer type coupling agent, or a maleic anhydride-styrene copolymer type coupling agent. joint agent. 5. The nylon composite material according to claim 1, characterized in that said antioxidant is a hindered phenolic antioxidant. 6. prepare the method for the described nylon composite material of claim 1, it is characterized in that step is as follows: (1) Nylon 66 slices, thermotropic liquid crystal polymer, needle-shaped mineral fiber, coupling agent and antioxidant with a weight ratio of 60:10:30:4.5:0.5 are uniformly mixed under stirring conditions; (2) Extrude, pull, pelletize at 280°C or 295°C, and make samples by injection molding to obtain nylon composite materials.