Antistatic pbt composite material and preparation method thereof

Abstract

The application relates to the technical field of materials, and discloses an antistatic PBT composite material and a preparation method thereof. The PBT composite material is added with auxiliary materials such as a compatilizer, short glass fibers and a modified carbon black additive. The modified carbon black additive is prepared by modifying a macromolecular structure material containing a large number of quaternary ammonium substituents of tetramethylpropylenediamine-polyphenyl ether alternating link on the surface of carbon black. The macromolecular structure material can form a pi-pi conjugation effect with PBT, can improve the compatibility between the carbon black and a polybutylene terephthalate matrix, can promote the uniform dispersion of the carbon black, the quaternary ammonium salt structure of the macromolecular structure material can form a bridge between carbon black particles and carbon black particles, and can form a perfect conductive path with the carbon black particles, thereby improving the antistatic performance of the composite material. The carbon black exists in the form of a crosslinking point, can efficiently utilize the effect of the carbon black as an inorganic additive, and can enhance the mechanical strength of the composite material.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to an antistatic PBT composite material and its preparation method. Background Technology

[0002] Polybutylene terephthalate (PBT) is a thermoplastic polyester produced by polycondensation reaction of terephthalic acid (PTA) and 1,4-butanediol (BDO). It is an important thermoplastic engineering plastic with excellent rigidity, fatigue resistance, dimensional stability, heat resistance, wear resistance and electrical properties. It is currently widely used in the fields of electronics, electrical engineering, automotive and aerospace.

[0003] Although polybutylene terephthalate (PET) already possesses excellent overall properties, its antistatic properties are poor. In fields such as electronics and electrical engineering, equipment is sensitive to static electricity. If PET is not modified for antistatic properties, the accumulation of static electricity may lead to equipment failure, data loss, or operational errors. In addition, PET is a brittle material with poor impact toughness. These defects greatly limit the application of PET in electronic equipment. Therefore, there is an urgent need to improve PET.

[0004] Currently, by adding conductive inorganic additives such as graphene to improve the conductivity of polybutylene terephthalate (PBT), antistatic modification of PBT can be achieved. However, this direct addition modification method is prone to agglomeration, making it difficult to achieve the actual modification effect. Moreover, the interfacial problems between the additives can also negatively affect the mechanical properties of the composite material. Based on this, the present invention provides a PBT composite material that can solve the problems existing in the prior art. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides an antistatic PBT composite material and its preparation method.

[0007] (II) Technical Solution

[0008] A method for preparing an antistatic PBT composite material, wherein the composite material is made from the following raw materials measured in parts by weight:

[0009] 68-75 parts PBT resin, 5-15 parts compatibilizer, 4-10 parts chopped glass fiber, 2-4.5 parts modified carbon black additive, 0.5-1 part antioxidant, and 1-2 parts lubricant;

[0010] The preparation method includes the following steps:

[0011] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0012] The second step is to add PBT resin, compatibilizer, modified carbon black additive, antioxidant and lubricant into a mixer and mechanically mix them evenly to form a mixture.

[0013] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 400-500 r / min and the temperature at 240-260℃, and perform melt extrusion to obtain the composite material.

[0014] More preferably, the compatibilizer is at least one of maleic anhydride-grafted SEBS, maleic anhydride-grafted POE, or maleic anhydride-grafted polyethylene.

[0015] More preferably, the preparation method of the modified carbon black additive includes the following steps:

[0016] Step 1: Acidify the carbon black with concentrated nitric acid to form acidified carbon black;

[0017] Step 2: Modify the surface of carbon black using a silane coupling agent containing halogen substituents to obtain halogenated carbon black.

[0018] Step 3: Using toluene as a medium, disperse the halogenated carbon black in the medium, then add tetramethylpropylenediamine to the medium and stir at 80-90℃ for 2-4 hours. Then add the halogenated polyphenylene ether to the medium and raise the temperature to 90-100℃. After holding at this temperature for 12-24 hours, separate the material to obtain the modified carbon black additive.

[0019] More preferably, the silane coupling agent containing halogen substituents is selected from any one of 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, or 3-chloropropyltriethoxysilane.

[0020] More preferably, the preparation method of the halopolyphenylene ether is as follows:

[0021] Hydroxyl-terminated polyphenylene ether is added to xylene and stirred until a homogeneous reaction solution is formed. Dry nitrogen gas is then introduced for protection. Halogenated modification reagent and dibutyltin dilaurate are then added to the reaction solution. After the addition is complete, the temperature is raised to 70-80℃ and stirred for 4-6 hours. The solution is then cooled and discharged. After purification, halogenated polyphenylene ether can be obtained.

[0022] More preferably, the number-average molecular weight of the terminal hydroxyl polyphenylene ether is 1600.

[0023] More preferably, the halogenated modifying agent is selected from any one of chloroethyl isocyanate, 3-chloropropyl isocyanate, or ethyl 2-bromoisocyanate.

[0024] More preferably, the molar ratio of the terminal hydroxyl polyphenylene ether to the halogenated modifying agent is 1:2.

[0025] In the above technical solution, carbon black is first acidified to generate oxygen-containing functional groups such as hydroxyl groups on its surface to obtain acidified carbon black. Then, carbon black is surface modified by using a silane coupling agent containing halogen substituents to obtain halogenated carbon black with halogen substituents on its surface. Then, tetramethylpropylenediamine is used as a bridging agent to first quaternize the halogenated carbon black, and then to carry out a continuous and complex quaternization reaction with halogenated polyphenylene ether, thereby forming a substance with a large number of quaternary ammonium substituents and alternating links of tetramethylpropylenediamine-polyphenylene ether macromolecular structures on the surface of carbon black, thus obtaining a carbon black additive.

[0026] Among them, halogenated polyphenylene ether is prepared by halogenating terminal hydroxyl polyphenylene ether with a halogenating agent under the action of a catalyst.

[0027] More preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, or antioxidant 168; and the lubricant is polyethylene wax or paraffin wax.

[0028] An antistatic PBT composite material was prepared using the method described above.

[0029] (III) Beneficial Technical Effects

[0030] This invention prepares a carbon black additive by modifying the surface of carbon black with a large molecular structure containing alternating links of tetramethylpropylenediamine and polyphenylene ether with a large number of quaternary ammonium substituents. First, the polyphenylene ether in the macromolecular structure can form a π-π conjugation with the benzene ring in the polybutylene terephthalate structure during high-temperature extrusion. This not only enables the mutual entanglement between molecular chains, but also significantly improves the compatibility between carbon black and the polybutylene terephthalate matrix, promoting the uniform dispersion of carbon black. Studies have found that uniform dispersion of carbon black can have an adverse effect on the construction of conductive pathways, while the quaternary ammonium salt structure of the macromolecular structure can form bridges between carbon black particles, synergistically forming a complete conductive pathway with the carbon black particles, thereby significantly improving the antistatic properties of the composite material.

[0031] In addition, due to the entanglement between the macromolecular structure and the PBT molecular chain, carbon black exists in the composite material in the form of cross-linking points. This also allows for the efficient use of carbon black as an inorganic additive to enhance the mechanical strength of the composite material. Detailed Implementation

[0032] To facilitate understanding of the present invention, a more complete description will be provided below. Preferred embodiments of the invention are given below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0033] Example 1

[0034] An antistatic PBT composite material is made from the following raw materials measured in parts by weight:

[0035] 68 parts PBT resin, 5 parts compatibilizer, 4 parts chopped glass fiber, 2 parts modified carbon black additive, 0.5 parts antioxidant, and 1 part lubricant polyethylene wax.

[0036] The preparation method of the PBT composite material includes the following steps:

[0037] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0038] The second step is to add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 1076 and lubricant polyethylene wax into a mixer and mechanically mix them evenly to form a mixture.

[0039] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 400 r / min and the temperature at 240℃, and perform melt extrusion to obtain the composite material.

[0040] The compatibilizer used is maleic anhydride grafted with SEBS, and the same applies to the following.

[0041] Example 2

[0042] An antistatic PBT composite material is made from the following raw materials measured in parts by weight:

[0043] 70 parts PBT resin, 10 parts compatibilizer, 8 parts chopped glass fiber, 4 parts modified carbon black additive, 3 parts antioxidant 10100, and 1.5 parts lubricant paraffin wax;

[0044] The preparation method of the PBT composite material includes the following steps:

[0045] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0046] The second step is to add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 1010 and lubricant paraffin into a mixer and mechanically mix them evenly to form a mixture.

[0047] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 450 r / min and the temperature at 260℃, and perform melt extrusion to obtain the composite material.

[0048] Example 3

[0049] An antistatic PBT composite material is made from the following raw materials measured in parts by weight:

[0050] 75 parts PBT resin, 15 parts compatibilizer, 10 parts chopped glass fiber, 4.5 parts modified carbon black additive, 1681 parts antioxidant, and 2 parts paraffin wax lubricant.

[0051] The preparation method of the PBT composite material includes the following steps:

[0052] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0053] The second step is to add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 168 and lubricant paraffin into a mixer and mechanically mix them evenly to form a mixture.

[0054] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 500 r / min and the temperature at 260℃, and perform melt extrusion to obtain the composite material.

[0055] The modified carbon black additives in the above embodiments were prepared using the following method:

[0056] Step 1: Add 5g of carbon black N330 to concentrated nitric acid, disperse it evenly, raise the temperature to 90℃, stir continuously for 2 hours, separate the solid material, wash it with water until neutral, and vacuum dry it to obtain acidified carbon black.

[0057] Step 2: Disperse 2.4g of acidified carbon black in a 70% (v / v) aqueous ethanol solution, then add 1.5g of 3-chloropropyltriethoxysilane to the resulting dispersion. After the addition is complete, heat to 70°C, keep warm and stir for 6 hours, then separate the solid material to obtain halogenated carbon black.

[0058] Step 3: Using toluene as a medium, disperse 1.8g of halogenated carbon black in the medium, then add 1.2g of tetramethylpropylenediamine to the medium and stir at 85℃ for 3 hours. Then add 0.5g of halogenated polyphenylene ether to the medium, raise the temperature to 95℃, keep it at that temperature for 18 hours, and then separate the material to obtain the modified carbon black additive.

[0059] The preparation method of halogenated polyphenylene ether is as follows:

[0060] 1.2 g of hydroxyl-terminated polyphenylene ether with a number average molecular weight of 1600 was added to xylene and stirred until a homogeneous reaction solution was formed. Dry nitrogen gas was then introduced for protection. 0.16 g of chloroethyl isocyanate and dibutyltin dilaurate were then added to the reaction solution. After the addition was complete, the temperature was raised to 75°C and stirred for 6 hours. The solution was then cooled and discharged. After purification, halogenated polyphenylene ether was obtained.

[0061] Comparative Example 1

[0062] An antistatic PBT composite material is made from the following raw materials measured in parts by weight:

[0063] 70 parts PBT resin, 10 parts compatibilizer, 8 parts chopped glass fiber, 4 parts carbon black N330, 3 parts antioxidant 10100, and 1.5 parts paraffin wax lubricant;

[0064] The preparation method of the PBT composite material includes the following steps:

[0065] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0066] The second step is to add PBT resin, compatibilizer 1010, carbon black N330, antioxidant 1010 and lubricant paraffin into a mixer and mechanically mix them evenly to form a mixture.

[0067] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 450 r / min and the temperature at 260℃, and perform melt extrusion to obtain the composite material.

[0068] Comparative Example 2

[0069] An antistatic PBT composite material is made from the following raw materials measured in parts by weight:

[0070] 70 parts PBT resin, 10 parts compatibilizer, 8 parts chopped glass fiber, 0.3 parts antioxidant, and 1.5 parts paraffin wax lubricant;

[0071] The preparation method of the PBT composite material includes the following steps:

[0072] Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation;

[0073] Step 2: Add PBT resin, compatibilizer 1010, antioxidant 1010 and lubricant paraffin to a mixer and mechanically mix them evenly to form a mixture.

[0074] The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed at 450 r / min and the temperature at 260℃, and perform melt extrusion to obtain the composite material.

[0075] Test case

[0076] The composite materials used in the examples and comparative examples were made into various test specimens, and corresponding performance tests were conducted. The results are recorded in Table 1:

[0077] Table 1 - Test Results

[0078] <![CDATA[Impact strength / kJ / m 2 > Volume resistivity Ω·m Example 1 24.1 <![CDATA[2.54×10 4 ]]> Example 2 24.5 <![CDATA[1.81×10 4 ]]> Example 3 24.4 <![CDATA[1.98×10 4 ]]> Comparative Example 1 19.7 <![CDATA[3.14×10 6 ]]> Comparative Example 2 12.9 <![CDATA[5.37×10 7 ]]>

[0079] Note: The test method for impact strength refers to standard GB / T 1843-2008;

[0080] Volume resistivity was measured directly using a four-probe resistivity meter.

[0081] Analysis shows that when carbon black is used alone as an additive, the mechanical properties of the composite material decrease significantly due to agglomeration problems, and it is difficult to form a continuous and stable conductive path, thus increasing the resistivity and reducing the antistatic effect.

[0082] In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] Based on the preferred embodiments of the present invention, and through the above description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing an antistatic PBT composite material, characterized in that, The composite material is made from the following raw materials measured in parts by weight: 68-75 parts PBT resin, 5-15 parts compatibilizer, 4-10 parts chopped glass fiber, 2-4.5 parts modified carbon black additive, 0.5-1 part antioxidant, and 1-2 parts lubricant; The preparation method includes the following steps: Step 1: Weigh each ingredient according to the specified weight proportions to complete the material preparation; The second step is to add PBT resin, compatibilizer, modified carbon black additive, antioxidant and lubricant into a mixer and mechanically mix them evenly to form a mixture. The third step is to feed the mixture into the twin-screw extruder through the main feed port, and feed the chopped glass fibers into the twin-screw extruder through the side feed port. Control the speed to be 400-500 r / min and the temperature to be 240-260℃, and perform melt extrusion to obtain the composite material. The preparation method of the modified carbon black additive includes the following steps: Step 1: Acidify the carbon black with concentrated nitric acid to form acidified carbon black; Step 2: Modify the surface of carbon black using a silane coupling agent containing halogen substituents to obtain halogenated carbon black. Step 3: Using toluene as a medium, disperse the halogenated carbon black in the medium, then add tetramethylpropylenediamine to the medium and stir at 80-90℃ for 2-4 hours. Then add the halogenated polyphenylene ether to the medium and raise the temperature to 90-100℃. After holding at this temperature for 12-24 hours, separate the material to obtain the modified carbon black additive.

2. The method for preparing an antistatic PBT composite material according to claim 1, characterized in that, The compatibilizer is at least one of maleic anhydride-grafted SEBS, maleic anhydride-grafted POE, or maleic anhydride-grafted polyethylene.

3. The method for preparing an antistatic PBT composite material according to claim 1, characterized in that, The silane coupling agent containing halogen substituents is selected from any one of 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, or 3-chloropropyltriethoxysilane.

4. The method for preparing an antistatic PBT composite material according to claim 1, characterized in that, The preparation method of the halopolyphenylene ether is as follows: Hydroxyl-terminated polyphenylene ether is added to xylene and stirred until a homogeneous reaction solution is formed. Dry nitrogen gas is then introduced for protection. Halogenated modification reagent and dibutyltin dilaurate are then added to the reaction solution. After the addition is complete, the temperature is raised to 70-80℃ and stirred for 4-6 hours. The solution is then cooled and discharged. After purification, halogenated polyphenylene ether can be obtained.

5. The method for preparing an antistatic PBT composite material according to claim 4, characterized in that, The number-average molecular weight of the terminal hydroxyl polyphenylene ether is 1600.

6. The method for preparing an antistatic PBT composite material according to claim 4, characterized in that, The halogenated modifying agent is selected from any one of chloroethyl isocyanate, 3-chloropropyl isocyanate, or ethyl 2-bromoisocyanate.

7. The method for preparing an antistatic PBT composite material according to claim 4, characterized in that, The molar ratio of the terminal hydroxyl polyphenylene ether to the halogenated modifying agent is 1:

2.

8. The method for preparing an antistatic PBT composite material according to claim 1, characterized in that, The antioxidant is at least one of antioxidant 1010, antioxidant 1076, or antioxidant 168; the lubricant is polyethylene wax or paraffin wax.

9. An antistatic PBT composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.