Antistatic PBT composite material and preparation method thereof

Abstract

The invention 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, chopped glass fibers and a modified carbon black additive; wherein the modified carbon black additive is prepared by modifying the surface of carbon black with a macromolecular structure substance which contains a large number of quaternary ammonium substituent groups and is alternately linked with tetramethylpropanediamine-polyphenyl ether, and the macromolecular structure substance can form a pi-pi conjugation effect with PBT (Polybutylene Terephthalate), so that the compatibility between the carbon black and a polybutylene terephthalate matrix can be improved; and the quaternary ammonium salt structure of the macromolecular structure substance can form a bridge between carbon black particles, and cooperates with the carbon black particles to form a perfect conductive path, so that the antistatic performance of the composite material is improved, and the carbon black exists in the form of crosslinking points, so that the antistatic property of the composite material is improved. The effect of carbon black serving as an inorganic additive can be efficiently utilized, and the mechanical strength of the composite material is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to an antistatic PBT composite material and a preparation method thereof. Background Art

[0002] Polybutylene terephthalate (PBT) is a thermoplastic polyester made from the condensation 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 has been widely used in electronics, electrical, automotive, aerospace and other fields.

[0003] Although polybutylene terephthalate (PBTE) itself has excellent comprehensive properties, its antistatic properties are poor. In the fields of electronics and electrical equipment, equipment is sensitive to static electricity. If polybutylene terephthalate is not modified for antistatic properties, its static electricity accumulation may cause equipment failure, data loss or operational errors. In addition, polybutylene terephthalate itself is a brittle material with poor impact toughness. These defects have greatly limited the application of polybutylene terephthalate in fields related to electronic equipment. Therefore, there is an urgent need to improve polybutylene terephthalate.

[0004] Currently, the antistatic properties of polybutylene terephthalate (PBTE) can be improved by adding conductive inorganic additives such as graphene. However, this direct addition modification method is prone to agglomeration, making it difficult to achieve the actual modification effect. In addition, the interface problems between the additives can easily have a negative impact on the mechanical properties of the composite material. Based on this, the present invention provides a PBT composite material that can solve the problems of the existing technology. Summary of the Invention

[0005] (1) Technical problems solved

[0006] In view of the deficiencies in the prior art, the present invention provides an antistatic PBT composite material and a preparation method thereof.

[0007] (2) 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 of PBT resin, 5-15 parts of compatibilizer, 4-10 parts of chopped glass fiber, 2-4.5 parts of modified carbon black additive, 0.5-1 part of antioxidant, 1-2 parts of lubricant;

[0010] The preparation method comprises the following steps:

[0011] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0012] Step 2: Add PBT resin, compatibilizer, modified carbon black additive, antioxidant and lubricant into a blender, and mechanically stir and mix them evenly to form a mixture;

[0013] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled to 400-500r / min and the temperature is 240-260℃. Melt extrusion is performed to obtain a 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] Further preferably, the preparation method of the modified carbon black additive comprises the following steps:

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

[0017] Step 2: Using a silane coupling agent containing a halogen substituent to modify the surface of carbon black 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, stir at a temperature of 80-90°C for 2-4 hours, then add the halogenated polyphenylene ether to the medium, and raise the temperature to 90-100°C. After keeping warm for 12-24 hours, separate the material to obtain the modified carbon black additive.

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

[0020] Further preferably, the preparation method of the halogenated polyphenylene ether is as follows:

[0021] Add the hydroxy-terminated polyphenylene ether to xylene, stir and mix until a uniform reaction liquid is formed, introduce dry nitrogen for protection, then add the halogenated modification reagent and dibutyltin dilaurate to the reaction liquid. After the addition is completed, raise the temperature to 70-80°C, keep stirring for 4-6 hours, cool and discharge the material, and undergo purification treatment to obtain the halogenated polyphenylene ether.

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

[0023] More preferably, the halogen modification agent is selected from any one of chloroethyl isocyanate, 3-chloropropyl isocyanate or 2-bromoethyl isocyanate.

[0024] More preferably, the molar ratio of the hydroxy-terminated polyphenylene ether to the halogenated modification agent is 1:2.

[0025] In the above technical solution, carbon black is first subjected to an acidification treatment to generate oxygen-containing functional groups such as hydroxyl groups on its surface to obtain acidified carbon black. Next, the carbon black is surface-modified using a silane coupling agent containing a halogen substituent to obtain a halogenated carbon black having a halogen substituent on its surface. Then, tetramethylpropylenediamine is used as a bridging agent to first undergo a quaternization reaction with the halogenated carbon black, and then a continuous and non-simple quaternization reaction is carried out with a halogenated polyphenylene ether, thereby forming a substance containing a large number of quaternary ammonium substituents on the surface of the carbon black, in which a macromolecular structure of tetramethylpropylenediamine and polyphenylene ether alternately linked is obtained to obtain a carbon black additive.

[0026] The halogenated polyphenylene ether is prepared by halogenating and modifying the terminal hydroxyl polyphenylene ether using a halogenation modification reagent under the action of a catalyst.

[0027] Further 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 is prepared by adopting the above preparation method.

[0029] (3) Beneficial technical effects

[0030] The present invention prepares a carbon black additive by modifying the surface of carbon black with a macromolecular structure substance containing a large number of quaternary ammonium substituents and alternately linked tetramethylpropylenediamine and polyphenylene ether. First, the polyphenylene ether in the macromolecular structure substance can form a π-π conjugation effect with the benzene ring in the polybutylene terephthalate structure during a high-temperature extrusion process, which not only enables mutual entanglement between molecular chains, but also greatly 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 has an adverse effect on the construction of a conductive path, while the quaternary ammonium salt structure of the macromolecular structure substance can form a bridge between carbon black particles, cooperate with the carbon black particles to form a complete conductive path, and thus greatly improve the antistatic properties of the composite material.

[0031] In addition, due to the mutual entanglement between the macromolecular structure substance and the PBT molecular chain, carbon black exists in the composite material in the form of cross-linking points. The effect of carbon black as an inorganic additive can also be efficiently utilized to enhance the mechanical strength of the composite material. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, the present invention will be described in more detail below. Preferred embodiments of the present invention are provided below. However, the present 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 more thorough and comprehensive understanding of the disclosure of the present 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 of PBT resin, 5 parts of compatibilizer, 4 parts of chopped glass fiber, 2 parts of modified carbon black additive, 10760.5 parts of antioxidant, 1 part of lubricant polyethylene wax;

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

[0037] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0038] Step 2: Add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 1076 and lubricant polyethylene wax into a blender, and mechanically stir and mix them evenly to form a mixture;

[0039] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled to 400r / min and the temperature is 240℃, and melt extrusion is performed to obtain a composite material.

[0040] The compatibilizer is maleic anhydride grafted SEBS, and the following are the same.

[0041] Example 2

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

[0043] 70 parts of PBT resin, 10 parts of compatibilizer, 8 parts of chopped glass fiber, 4 parts of modified carbon black additive, 10100.3 parts of antioxidant, 1.5 parts of lubricant paraffin;

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

[0045] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0046] Step 2: Add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 1010 and lubricant paraffin into a blender, and mechanically stir and mix them evenly to form a mixture;

[0047] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled at 450r / min and the temperature is 260°C. Melt extrusion is performed to obtain a 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 of PBT resin, 15 parts of compatibilizer, 10 parts of chopped glass fiber, 4.5 parts of modified carbon black additive, 1681 parts of antioxidant, 2 parts of lubricant paraffin;

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

[0052] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0053] Step 2: Add PBT resin, compatibilizer 1010, modified carbon black additive, antioxidant 168 and lubricant paraffin into a blender, and mechanically stir and mix them evenly to form a mixture;

[0054] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled to 500r / min and the temperature is 260℃. Melt extrusion is performed to obtain a composite material.

[0055] The modified carbon black additive in the above embodiment is prepared by the following method:

[0056] Step 1: Add 5g of carbon black N330 to concentrated nitric acid, disperse evenly, raise the temperature to 90°C, continue stirring for 2h, separate the solid material, wash with water until neutral, and vacuum dry to obtain acidified carbon black;

[0057] Step 2: Disperse 2.4 g of acidified carbon black in a 70% by volume ethanol aqueous solution, then add 1.5 g of 3-chloropropyltriethoxysilane to the resulting dispersion. After the addition is complete, heat to 70° C., stir at this temperature for 6 h, and separate the solid material to obtain halogenated carbon black.

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

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

[0060] 1.2 g of hydroxy-terminated polyphenylene ether with a number average molecular weight of 1600 was added to xylene and stirred to form a uniform reaction liquid. Dry nitrogen was introduced for protection. 0.16 g of chloroethyl isocyanate and dibutyltin dilaurate were then added to the reaction liquid. After the addition was completed, the temperature was raised to 75°C, the mixture was stirred for 6 hours, and the temperature was lowered and the material was discharged. After purification, the 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 of PBT resin, 10 parts of compatibilizer, 8 parts of chopped glass fiber, 4 parts of carbon black N330, 0.3 parts of antioxidant 1010, and 1.5 parts of lubricant paraffin;

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

[0065] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0066] Step 2: Add PBT resin, compatibilizer 1010, carbon black N330, antioxidant 1010 and lubricant paraffin into a blender, and mechanically stir and mix them evenly to form a mixture;

[0067] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled at 450r / min and the temperature is 260°C. Melt extrusion is performed to obtain a 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 of PBT resin, 10 parts of compatibilizer, 8 parts of chopped glass fiber, 10100.3 parts of antioxidant, and 1.5 parts of lubricant paraffin;

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

[0072] The first step is to weigh each raw material according to the weight to complete the material preparation;

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

[0074] The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled at 450r / min and the temperature is 260°C. Melt extrusion is performed to obtain a composite material.

[0075] Test Case

[0076] The composite materials in the examples and comparative examples were made into test specimens and subjected to corresponding performance tests. 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 the standard GB / T 1843-2008;

[0080] The volume resistivity is directly tested using a four-probe resistivity tester.

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

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples and the features of different embodiments or examples described in this specification without contradiction.

[0083] Based on the ideal embodiments of the present invention, and with reference to the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present invention. The technical scope of the present 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 of the following raw materials measured in parts by weight: 68-75 parts of PBT resin, 5-15 parts of compatibilizer, 4-10 parts of chopped glass fiber, 2-4.5 parts of modified carbon black additive, 0.5-1 part of antioxidant, 1-2 parts of lubricant; The preparation method comprises the following steps: The first step is to weigh each raw material according to the weight to complete the material preparation; Step 2: Add PBT resin, compatibilizer, modified carbon black additive, antioxidant and lubricant into a blender, and mechanically stir and mix them evenly to form a mixture; The third step is to feed the mixed material into the twin-screw extruder through the main feeding port, and feed the chopped glass fiber from the side feeding port of the twin-screw extruder. The speed is controlled to 400-500r / min and the temperature is 240-260℃. Melt extrusion is performed to obtain a composite material.

2. The method for preparing an antistatic PBT composite material according to claim 1, wherein: 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 preparation method of the modified carbon black additive comprises the following steps: Step 1: acidifying the carbon black with concentrated nitric acid to form acidified carbon black; Step 2: Using a silane coupling agent containing a halogen substituent to modify the surface of carbon black 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, stir at a temperature of 80-90°C for 2-4 hours, then add the halogenated polyphenylene ether to the medium, and raise the temperature to 90-100°C. After keeping warm for 12-24 hours, separate the material to obtain the modified carbon black additive.

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

5. The method for preparing an antistatic PBT composite material according to claim 3, characterized in that: The preparation method of the halogenated polyphenylene ether is as follows: Add the hydroxy-terminated polyphenylene ether to xylene, stir and mix until a uniform reaction liquid is formed, introduce dry nitrogen for protection, then add the halogenated modification reagent and dibutyltin dilaurate to the reaction liquid. After the addition is completed, raise the temperature to 70-80°C, keep stirring for 4-6 hours, cool and discharge the material, and undergo purification treatment to obtain the halogenated polyphenylene ether.

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

7. The method for preparing an antistatic PBT composite material according to claim 5, characterized in that: The halogenated modification agent is selected from any one of chloroethyl isocyanate, 3-chloropropyl isocyanate or 2-bromoethyl isocyanate.

8. The method for preparing an antistatic PBT composite material according to claim 5, characterized in that: The molar ratio of the hydroxy-terminated polyphenylene ether to the halogenated modification agent is 1:

2.

9. 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.

10. An antistatic PBT composite material, characterized in that: The method is as described in any one of claims 1 to 9.