Conductive reinforced flame-retardant PBT (polybutylene terephthalate) material and preparation method thereof

Abstract

The invention relates to a conductive reinforced flame-retardant PBT (Polybutylene Terephthalate) material. The conductive reinforced flame-retardant PBT material is prepared from the following components in parts by mass: 50 to 70 parts of PBT resin, 15 to 30 parts of modified compatilizer, 10 to 20 parts of halogen-free flame retardant and 0.1 to 2 parts of additive, wherein the modified compatilizer is a ternary random copolymer obtained by melting PE (Polyethylene), glycidyl methacrylate and carbon nanotube grafted acrylate at high temperature. The modified compatilizer is compounded with the PBT resin, the flame retardant and other components, the compatibilization effect is good, the combination effect among multiple components is improved, the mechanical property of the composite material is guaranteed, meanwhile, the product is endowed with better conductivity and flame retardance, and the defects existing in existing products are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of polymer composite materials, in particular to a conductive enhanced flame retardant PBT material and a preparation method thereof. Background Art

[0002] PBT (polybutylene terephthalate) is an economical, low-cost and versatile aromatic polyester material. It is a key thermoplastic polyester and one of the five major engineering plastics. PBT is widely used in many industrial fields such as electrical, aviation, communications, vehicles, and household appliances due to its excellent mechanical strength, excellent thermal stability, and strong water resistance.

[0003] By adding carbon fiber, metal powder and other substances, PBT conductive materials can be produced. While maintaining the original PBT properties, the material has better conductivity and antistatic properties, which improves its use in more environments. It can be applied to a variety of fields such as antistatic instruments, antistatic packaging, high-precision workbenches, conductive components, etc.

[0004] There are also many reports on the fire retardant properties of PBT materials. The use of flame retardants and PBT compounding can effectively improve the fire resistance of composite materials, significantly reduce the speed of flame spread, and even achieve self-extinguishing under certain conditions. By adding an appropriate amount of flame retardant, PBT flame retardant materials can reach the UL94 V-0 flame retardant standard, thereby greatly improving the safety of the product.

[0005] However, directly adding a large amount of conductive substances or flame retardants to PBT resins results in low compatibility between multiple components, resulting in insufficient material stability, difficulty in achieving ideal conductivity and fire resistance, and significantly reduced mechanical strength of the composite material. Therefore, how to develop a PBT composite material with strong electrical properties, flame retardant properties, and mechanical properties is a difficult problem faced by this field.

[0006] In summary, it is urgent to develop a new technical solution to solve the problems existing in the prior art. Summary of the invention

[0007] Based on this, the present invention has developed a conductive enhanced flame retardant PBT material. The present invention uses a modified compatibilizer obtained by reacting PE (polyethylene), glycidyl methacrylate, and carbon nanotube grafted acrylate as a component, and compounded with PBT resin and flame retardant and other ingredients, which has a good volume expansion effect, improves the combination effect between multiple components, and while ensuring the mechanical properties of the composite material, gives the product better conductivity and flame retardancy, overcoming the defects of existing products.

[0008] One object of the present invention is to provide a conductive enhanced flame retardant PBT material, wherein the conductive enhanced flame retardant PBT material comprises the following components in parts by mass:

[0009] PBT resin 50-70 parts

[0010] Modified compatibilizer 15-30 parts

[0011] Halogen-free flame retardant 10-20 parts

[0012] Additives 0.1-2 parts;

[0013] in,

[0014] The modified compatibilizer is a ternary random copolymer obtained by melting PE, glycidyl methacrylate and carbon nanotube-grafted acrylate at high temperature.

[0015] Furthermore, the mass ratio of the PE, glycidyl methacrylate, and carbon nanotube-grafted acrylate is (80-100):(1-10):(60-100).

[0016] Furthermore, the halogen-free flame retardant is selected from one or more of phosphate esters, phosphinates or diphosphates.

[0017] Furthermore, the auxiliary agent includes a nucleating agent, an antioxidant and a dispersant.

[0018] Another object of the present invention is to provide a method for preparing the above-mentioned conductive enhanced flame-retardant PBT material, comprising the following steps:

[0019] S1. Preparation of carbon nanotube-grafted acrylate:

[0020] The hydroxylated carbon nanotubes are added into acrylic acid and ultrasonically heated to obtain carbon nanotube-grafted acrylic acid ester;

[0021] S2. Preparation of modified compatibilizer:

[0022] PE, glycidyl methacrylate, carbon nanotube grafted acrylate and initiator are uniformly mixed, added into a twin-screw extruder, melt-reacted, then extruded, cooled and pelletized to obtain a modified compatibilizer of a ternary random copolymer;

[0023] S3. Preparation of conductive enhanced flame retardant PBT material:

[0024] The modified compatibilizer, PBT resin, halogen-free flame retardant and auxiliary agent are added into a twin-screw extruder, melt-extruded, cooled and pelletized to obtain a conductive enhanced flame-retardant PBT material.

[0025] Furthermore, in step S1, the temperature of the ultrasonic heating is 60-100°C.

[0026] Furthermore, in step S2, the temperature of the melting reaction is 160-190°C.

[0027] Furthermore, in step S3, the temperature of the melt extrusion is 220-250°C.

[0028] The present invention has the following beneficial effects:

[0029] The conductive enhanced flame retardant PBT material provided by the present invention is compounded with a modified compatibilizer, a PBT resin, a flame retardant and other components. The modified compatibilizer first adds hydroxylated carbon nanotubes to acrylic acid to react, introduces double bond functional groups, and then further reacts with PE and methacrylate glycidyl ether in a melt to obtain a terpolymer, and the obtained modified compatibilizer grafts carbon nanotubes with PE and methacrylate glycidyl ether through covalent bonds. On the one hand, the component is mainly based on carbon nanotubes, has good electrical conductivity, and has certain flame retardant and reinforcing functions. After the introduction of active vinyl and epoxy groups, the interface bonding force and compatibility with the organic resin can be improved, thereby improving the uniformity and stability of the composite material, avoiding the agglomeration phenomenon caused by the incompatibility between organic and inorganic components, and is beneficial to enhancing the mechanical properties, electrical conductivity and flame retardancy of the product; on the other hand, when the modified compatibilizer is combined with the matrix resin through chemical bonds, a more compact and three-dimensional network cross-linked structure can be formed, thereby further improving the toughness and strength of the PBT composite material, and the conductive and flame retardant components uniformly combined and distributed in the organic resin can also effectively exert dielectric and flame retardant functions. Therefore, the conductive enhanced flame retardant PBT material of the present invention not only ensures the electrical and flame retardant capabilities of the product, but also improves the mechanical strength of the composite material, and has good application prospects. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0031] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0032] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0033] The PBT resin in the embodiment of the present invention is BASF PBT B-4500.

[0034] The halogen-free flame retardant in the embodiment of the present invention is triphenyl phosphate and aluminum diethylphosphinate in a mass ratio of 1:1.

[0035] The nucleating agent in the embodiment of the present invention is NA-21.

[0036] The antioxidant in the embodiment of the present invention is antioxidant 1010.

[0037] The dispersant in the embodiment of the present invention is pentaerythritol stearate.

[0038] The hydroxyl content of the hydroxylated carbon nanotubes in the embodiment of the present invention is 4 wt %, and they were purchased from Xi'an Qiyue Biotechnology Co., Ltd.

[0039] The PE in the embodiment of the present invention is a linear low-density polyethylene purchased from Maoming Branch of Sinopec.

[0040] Unless otherwise stated, the parts mentioned in the present invention refer to the parts by mass.

[0041] Example 1

[0042] A conductive enhanced flame retardant PBT material, the conductive enhanced flame retardant PBT material comprising the following components in parts by mass:

[0043]

[0044]

[0045] The preparation method of the above conductive enhanced flame retardant PBT material comprises the following steps:

[0046] S1. Preparation of carbon nanotube-grafted acrylate:

[0047] The hydroxylated carbon nanotubes were immersed in acrylic acid, subjected to ultrasonic reaction at 80°C for 12 hours, and then filtered, washed and dried to obtain the carbon nanotube-grafted acrylic acid ester;

[0048] S2. Preparation of modified compatibilizer:

[0049] PE, glycidyl methacrylate, carbon nanotube grafted acrylate and di-tert-butyl peroxyisopropylbenzene in a mass ratio of 80:7:90:2 are mixed evenly, added into a twin-screw extruder, melt-reacted at 160-190° C., then extruded, cooled, and pelletized to obtain a modified compatibilizer for a ternary random copolymer;

[0050] S3. Preparation of conductive enhanced flame retardant PBT material:

[0051] The modified compatibilizer, PBT resin, halogen-free flame retardant, nucleating agent, antioxidant and dispersant are added into a twin-screw extruder according to the above mass fractions, melt-extruded at 220-240° C., cooled and pelletized to obtain a conductive enhanced flame-retardant PBT material.

[0052] Example 2

[0053] A conductive enhanced flame retardant PBT material, the conductive enhanced flame retardant PBT material comprising the following components in parts by mass:

[0054]

[0055] The preparation method of the above conductive enhanced flame retardant PBT material comprises the following steps:

[0056] S1. Preparation of carbon nanotube-grafted acrylate:

[0057] The hydroxylated carbon nanotubes were immersed in acrylic acid, subjected to ultrasonic reaction at 80°C for 12 hours, and then filtered, washed and dried to obtain the carbon nanotube-grafted acrylic acid ester;

[0058] S2. Preparation of modified compatibilizer:

[0059] PE, glycidyl methacrylate, carbon nanotube grafted acrylate and di-tert-butyl peroxyisopropylbenzene in a mass ratio of 80:8:100:2 are mixed evenly, added into a twin-screw extruder, melt-reacted at 160-190° C., then extruded, cooled and pelletized to obtain a modified compatibilizer of a ternary random copolymer;

[0060] S3. Preparation of conductive enhanced flame retardant PBT material:

[0061] The modified compatibilizer, PBT resin, halogen-free flame retardant, nucleating agent, antioxidant and dispersant are added into a twin-screw extruder according to the above mass fractions, melt-extruded at 220-240° C., cooled and pelletized to obtain a conductive enhanced flame-retardant PBT material.

[0062] Example 3

[0063] A conductive enhanced flame retardant PBT material, the conductive enhanced flame retardant PBT material comprising the following components in parts by mass:

[0064]

[0065] The preparation method of the above conductive enhanced flame retardant PBT material comprises the following steps:

[0066] S1. Preparation of carbon nanotube-grafted acrylate:

[0067] The hydroxylated carbon nanotubes were immersed in acrylic acid, subjected to ultrasonic reaction at 80°C for 12 hours, and then filtered, washed and dried to obtain the carbon nanotube-grafted acrylic acid ester;

[0068] S2. Preparation of modified compatibilizer:

[0069] PE, glycidyl methacrylate, carbon nanotube grafted acrylate and di-tert-butyl peroxyisopropylbenzene in a mass ratio of 80:8:90:2 are mixed evenly, added into a twin-screw extruder, melt-reacted at 160-190° C., then extruded, cooled and pelletized to obtain a modified compatibilizer for a ternary random copolymer;

[0070] S3. Preparation of conductive enhanced flame retardant PBT material:

[0071] The modified compatibilizer, PBT resin, halogen-free flame retardant, nucleating agent, antioxidant and dispersant are added into a twin-screw extruder according to the above mass fractions, melt-extruded at 220-240° C., cooled and pelletized to obtain a conductive enhanced flame-retardant PBT material.

[0072] Comparative Example 1

[0073] A PBT material. The difference between this comparative example and Example 1 is that step S1 is omitted, the acrylate grafted with carbon nanotubes is replaced with carbon nanotubes of equal mass, and the other components are the same as those in Example 1.

[0074] Comparative Example 2

[0075] A PBT material, the difference between this comparative example and Example 1 is that: steps S1 and S2 are omitted, the modified compatibilizer is replaced by a physical mixture of PE and carbon nanotubes in a mass ratio of 1:1, and other components and preparation methods are the same as those in Example 1.

[0076] Test Case

[0077] Test method:

[0078] The performance of the PBT materials prepared in the examples and comparative examples was tested according to standards such as ASTM-D638, ASTM-D256, and UL-94.

[0079] The test results are shown in Table 1:

[0080] Table 1 Performance test results

[0081] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength / MPA 126 119 123 99 82 Bending strength / MPA 177 172 175 154 121 <![CDATA[Impact strength / KJ / m 2 > 11.2 11.0 11.1 10.2 8.4 Flame retardant V-0 V-0 V-0 V-1 V-1 Surface resistance / Ω <![CDATA[10 5 ]]> <![CDATA[10 5 ]]> <![CDATA[10 5 ]]> <![CDATA[10 6 ]]> <![CDATA[10 6 ]]>

[0082] The test results show that the conductive enhanced flame retardant PBT material prepared in the embodiment has good mechanical strength, excellent flame retardancy and lower surface resistance, while the modified compatibilizer in Comparative Examples 1-2 is replaced by carbon nanotubes, PE, methyl glycidyl ether molten reactants or a mixture of carbon nanotubes and PE, resulting in a significant decrease in the compatibility between the components, the components are more likely to agglomerate, difficult to disperse evenly, and unable to obtain a three-dimensional structure formed by cross-linking of multiple components, resulting in varying degrees of decrease in the mechanical properties, flame retardancy and dielectric properties of the composite material. In summary, the conductive enhanced flame retardant PBT material of the present invention solves the problems and defects of the prior art, and is of great significance to the further development and application of PBT materials.

[0083] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0084] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A conductive enhanced flame retardant PBT material, characterized in that: The conductive enhanced flame retardant PBT material comprises the following components in parts by mass: in, The modified compatibilizer is a ternary random copolymer obtained by melting PE, glycidyl methacrylate and carbon nanotube-grafted acrylate at high temperature.

2. The conductive enhanced flame retardant PBT material according to claim 1, characterized in that: The mass ratio of the PE, glycidyl methacrylate and carbon nanotube grafted acrylate is (80-100):(1-10):(60-100).

3. The conductive enhanced flame retardant PBT material according to claim 1, characterized in that: The halogen-free flame retardant is selected from one or more of phosphate esters, phosphinates or diphosphates.

4. The conductive enhanced flame retardant PBT material according to claim 1, characterized in that: The auxiliary agents include nucleating agents, antioxidants and dispersants.

5. The method for preparing the conductive enhanced flame retardant PBT material according to any one of claims 1 to 4, characterized in that: The steps include: S1. Preparation of carbon nanotube-grafted acrylate: The hydroxylated carbon nanotubes are added into acrylic acid and ultrasonically heated to obtain carbon nanotube-grafted acrylic acid ester; S2. Preparation of modified compatibilizer: PE, glycidyl methacrylate, carbon nanotube grafted acrylate and initiator are uniformly mixed, added into a twin-screw extruder, melt-reacted, then extruded, cooled and pelletized to obtain a modified compatibilizer of a ternary random copolymer; S3. Preparation of conductive enhanced flame retardant PBT material: The modified compatibilizer, PBT resin, halogen-free flame retardant and auxiliary agent are added into a twin-screw extruder, melt-extruded, cooled and pelletized to obtain a conductive enhanced flame-retardant PBT material.

6. The method for preparing the conductive enhanced flame retardant PBT material according to claim 5, characterized in that: In step S1, the temperature of the ultrasonic heating is 60-100°C.

7. The method for preparing the conductive enhanced flame retardant PBT material according to claim 5, characterized in that: In step S2, the temperature of the melting reaction is 160-190°C.

8. The method for preparing the conductive enhanced flame retardant PBT material according to claim 5, characterized in that: In step S3, the temperature of the melt extrusion is 220-250°C.

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