Alloy master batch capable of being sprayed on line and preparation process

Abstract

The invention relates to the technical field of master batch manufacturing processes, in particular to an alloy master batch capable of being sprayed on line, which comprises the following components in percentage by mass: 40-50% of polyamide, 30-40% of polyphenyl ether, 5-15% of graft modified polyphenyl ether, 10-20% of thermoplastic elastomer, 1-5% of conductive carbon nanotube and 0.2-1% of assistant. According to the alloy master batch, the polyamide, the polyphenyl ether, the graft modified polyphenyl ether, the thermoplastic elastomer, the conductive carbon nanotubes and the auxiliaries are subjected to composite formula design according to a specific proportion, so that an engineering plastic material with good conductivity, flowability and thermal stability is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of masterbatch manufacturing technology, in particular to an alloy masterbatch capable of online spraying and a preparation process thereof. Background Art

[0002] As the automotive industry rapidly develops toward lightweighting, electrification, and intelligent driving, automotive exterior components such as fuel tank caps, charging port covers, door panels, and bumpers are placing higher demands on the comprehensive performance of materials. In particular, in the spraying process, online spraying technology (where parts enter the spraying line along with the vehicle and undergo high-temperature baking) is gradually replacing traditional offline spraying and becoming the mainstream trend due to its advantages such as minimal color variation, high matching accuracy, high process intensiveness, and environmental protection and energy conservation.

[0003] Traditionally, the materials used for these components have primarily been metals and modified engineering plastics such as polycarbonate / acrylonitrile-butadiene-styrene and polycarbonate / polybutylene terephthalate. While these materials offer certain moldability and mechanical properties, they generally suffer from the following drawbacks: low heat distortion temperatures, unable to withstand the 140-160°C baking temperatures required for online spraying; poor electrical conductivity, unable to meet the electrical conductivity requirements of electrostatic spraying; insufficient dimensional stability, prone to warping and deformation; and challenges in achieving high-performance or integrated functional designs.

[0004] In recent years, polyphenylene ether and polyamide have been widely studied for the preparation of high-performance blends due to their respective excellent thermal properties, dimensional stability, mechanical strength and molding processing properties. Among them, polyphenylene ether has a high glass transition temperature (about 215°C) and low water absorption, while polyamide has good flexibility, fluidity and chemical resistance. The two can achieve complementary performance after blending. However, due to the large difference in polarity and poor compatibility between polyphenylene ether and polyamide, the alloy materials obtained by direct blending usually have poor dispersibility and unsatisfactory mechanical properties, which seriously restricts their application in the industrial field.

[0005] Furthermore, to meet the conductivity requirements of in-line spray coating, conductive fillers such as carbon black, conductive carbon fibers, or carbon nanotubes are often introduced into the alloy system. However, while these fillers improve conductivity, they can also significantly reduce the material's fluidity and processability. This can lead to issues such as incomplete mold filling and surface defects during the molding of complex automotive parts. Therefore, achieving conductivity while simultaneously improving the material's fluidity, compatibility, and thermal stability has become a critical challenge in this field. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems pointed out in the background technology and to propose an alloy masterbatch that can be sprayed online.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The invention discloses an alloy masterbatch capable of online spraying, comprising: 40-50% polyamide, 30-40% polyphenylene ether, 5-15% graft-modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% auxiliary agent, wherein the above components are expressed in mass percentage.

[0009] The present invention proposes an alloy masterbatch capable of online spraying, which has the beneficial effect of preparing an engineering plastic material with good conductivity, fluidity and thermal stability by compounding a formula of polyamide, polyphenylene ether, graft-modified polyphenylene ether, thermoplastic elastomer, conductive carbon nanotubes and additives in specific proportions.

[0010] A process for preparing an alloy masterbatch capable of online spraying includes the above-mentioned alloy masterbatch, and the preparation process comprises the following steps:

[0011] a. Preparation of graft-modified polyphenylene ether;

[0012] b. Blending 40-50% polyamide, 30-40% polyphenylene ether, 5-15% graft-modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% additive according to mass percentage to obtain a first mixture;

[0013] c. extruding the first mixture in a temperature zone manner;

[0014] d. Cooling and pelletizing the product extruded in step c to obtain an alloy masterbatch.

[0015] The present invention proposes a process for preparing an alloy masterbatch capable of online spray coating. The beneficial effects of this process lie in the following: This process involves reacting a graft-modified polyphenylene ether with a polyamide nylon base, grafting maleic anhydride onto the polyphenylene ether backbone under controlled temperature conditions in the presence of an initiator, to form a grafted structure with active functional groups. The key to this step lies in precisely controlling the grafting reaction conditions to ensure that the resulting modified polyphenylene ether is capable of chemically bonding with the polyamide, thereby enhancing the compatibility between the two incompatible substrates, improving the overall structural uniformity and mechanical properties of the material, and avoiding defects such as interfacial delamination and delamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0018] Reference Figure 1 An alloy masterbatch that can be sprayed online includes: 40-50% polyamide, 30-40% polyphenylene ether, 5-15% grafted modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% additives, with the above components being expressed in mass percentage.

[0019] Graft-modified polyphenylene ether is a product formed by grafting maleic anhydride onto the main chain of polyphenylene ether under the action of an initiator.

[0020] The amount of maleic anhydride added to the graft-modified polyphenylene ether is 1-5% of the mass of the polyphenylene ether, and the initiator is dicumyl peroxide, and the amount of dicumyl peroxide added is 0.2-1% of the mass of the polyphenylene ether.

[0021] The conductive carbon nanotubes are distributed in the interface region between polyphenylene ether and polyamide during the processing.

[0022] This alloy masterbatch is designed through a composite formula of polyamide, polyphenylene ether, graft-modified polyphenylene ether, thermoplastic elastomer, conductive carbon nanotubes and additives in specific proportions, thereby preparing an engineering plastic material with good conductivity, fluidity and thermal stability.

[0023] The graft-modified polyphenylene ether is produced by grafting maleic anhydride onto the polyphenylene ether backbone in the presence of an initiator. By controlling the amount of maleic anhydride added to 1-5% of the polyphenylene ether mass and the initiator addition to 0.2-1% of the polyphenylene ether mass, a grafted structure with active functional groups can be stably generated in the molten state. This structure chemically reacts with the end groups of the polyamide molecular chain, significantly improving the interfacial compatibility between the polyphenylene ether and polyamide, resolving the problem of severe phase separation and reduced mechanical properties in traditional blends of the two.

[0024] During processing, the conductive carbon nanotubes are evenly distributed at the interface between polyphenylene ether and polyamide, forming a stable conductive network. This layout not only achieves permanent conductivity, meeting the conductivity requirements of the electrostatic spraying process, but also avoids reduced fluidity and product molding defects caused by the aggregation of conductive fillers.

[0025] A process for preparing an alloy masterbatch capable of online spraying includes the above-mentioned alloy masterbatch, and the preparation process comprises the following steps:

[0026] a. Preparation of graft-modified polyphenylene ether;

[0027] b. Blending 40-50% polyamide, 30-40% polyphenylene ether, 5-15% graft-modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% additive according to mass percentage to obtain a first mixture; wherein the polyamide is polyamide 66;

[0028] c. extruding the first mixture in a temperature zone manner;

[0029] d. Cooling and pelletizing the product extruded in step c to obtain an alloy masterbatch.

[0030] The base resin is polyamide, with a glass transition temperature of 55°C and a melting point of 265°C, and it has chemical corrosion resistance and easy processing performance (fluidity). The base resin is polyphenylene ether, with a glass transition temperature of 215°C, and it has high thermal performance, excellent dimensional stability and low specific gravity. The thermoplastic elastomer is styrene-butadiene-styrene rubber, which mainly plays a toughening role. The conductive carbon filler is carbon nanotubes (CNT) to enhance the conductivity of the material.

[0031] This process involves reacting graft-modified polyphenylene ether with a polyamide nylon base. Maleic anhydride is grafted onto the polyphenylene ether backbone under controlled temperature conditions and in the presence of an initiator, forming a grafted structure with active functional groups. The key to this step is precisely controlling the grafting reaction conditions to ensure that the resulting modified polyphenylene ether is capable of chemically bonding with the polyamide, thereby enhancing the compatibility between the two incompatible matrices, improving the uniformity of the overall material structure and its mechanical properties, and avoiding defects such as interfacial delamination and delamination.

[0032] In step c, the first mixture is fed into a twin-screw extruder, and the extrusion temperature is controlled to be 280-300°C.

[0033] The preparation of graft-modified polyphenylene ether includes the following steps: adding dried polyphenylene ether, maleic anhydride and an initiator into a twin-screw extruder, melt-blending them in a temperature range of 180 to 260°C, completing the maleic anhydride grafting reaction, and obtaining the graft-modified polyphenylene ether, wherein the amount of maleic anhydride added is 1 to 5% of the mass of the polyphenylene ether, and the initiator is dicumyl peroxide, and the amount of dicumyl peroxide added is 0.2 to 1% of the mass of the polyphenylene ether.

[0034] The amount of maleic anhydride should not be too much, otherwise it may cause self-polymerization side reactions. The amount of initiator also needs to be moderate to balance the grafting rate and side reactions.

[0035] First, the initiator decomposes under thermal conditions, generating free radicals. These free radicals then extract hydrogen atoms from the polymer backbone, forming reactive macromolecular free radicals. These macromolecular free radicals then react with maleic anhydride monomers, introducing anhydride functional groups onto the polymer chain and completing the grafting process. The resulting grafted product contains anhydride groups that react with amino groups at the end of the other polymer chain to form an imide structure. This reaction significantly reduces the interfacial tension between the two polymers, improving their interfacial bonding and thereby enhancing the structural stability and overall performance of the material.

[0036] It should be noted that the polyphenylene ether (PPE) resin must be pre-dried (e.g., vacuum-dried at 120°C for 4 hours to prevent moisture from affecting the reaction). Maleic anhydride should be in powder form, ≥99% purity, and ground to an appropriate particle size. Initiator: Dicumyl peroxide should be used at a dosage of 0.2-1.0 wt% based on the PPE. Antioxidant: Optional (e.g., B215, 1010, 168) to prevent high-temperature degradation.

[0037] During melt blending in the temperature range of 180-260°C, the feeding zone is 180-200°C, which prevents premature reaction of maleic anhydride; the melting zone is 220-240°C, at which the polyphenylene ether melts; the reaction zone is 240-260°C, at which the initiator decomposes and the grafting reaction occurs; and the die zone is 230-250°C, at which degradation is avoided.

[0038] During the grafting reaction, a vacuum exhaust port is provided in the middle of the extruder to remove unreacted maleic anhydride and its by-products.

[0039] The twin-screw extruder's screw speed is controlled between 200 and 400 rpm, and the material's residence time in the reaction zone is controlled within 1 to 5 minutes. The grafting reaction residence time is typically 1 to 5 minutes, which should match the initiator's half-life (e.g., DCP has a half-life of approximately 1 minute at 240°C). Shear strength is enhanced through screw element design (e.g., kneading blocks), but excessive shearing that can cause degradation should be avoided.

[0040] Furthermore, during extrusion granulation, the melt is extruded through a die and then water-cooled and pelletized, and then washed with acetone / ethanol to remove unreacted maleic anhydride and homopolymer.

[0041] In order to reduce the volatilization of maleic anhydride, side feeding or sealed feeding system is used to control the MAH concentration and shear rate to avoid homopolymerization.

[0042] This technical solution forms a systematic optimization in terms of material formulation, grafting modification, distribution control and extrusion process, and successfully develops a new alloy masterbatch that is adaptable to online spraying process, has long-term conductivity and comprehensive mechanical properties, and has significant technological innovation and application promotion value.

[0043] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solution, conception, and design obtained by equivalent replacement or modification of the technical solution and inventive concept of the present invention by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. An alloy masterbatch capable of online spraying, characterized in that: The alloy masterbatch comprises: 40-50% polyamide, 30-40% polyphenylene ether, 5-15% graft-modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% additives, with the above components expressed in mass percentage.

2. The alloy masterbatch capable of online spraying according to claim 1, characterized in that: The graft-modified polyphenylene ether is a product formed by grafting maleic anhydride onto the main chain of polyphenylene ether under the action of an initiator.

3. The alloy masterbatch capable of online spraying according to claim 2, characterized in that: The amount of maleic anhydride added to the graft-modified polyphenylene ether is 1-5% of the mass of the polyphenylene ether; the initiator is dicumyl peroxide, and the amount of dicumyl peroxide added is 0.2-1% of the mass of the polyphenylene ether.

4. The alloy masterbatch capable of online spraying according to claim 1, characterized in that: The conductive carbon nanotubes are distributed in the interface region between polyphenylene ether and polyamide during the processing.

5. A process for preparing alloy masterbatch capable of online spraying, characterized in that: The alloy masterbatch according to any one of claims 1 to 4 is prepared by the following steps: a. Preparation of graft-modified polyphenylene ether; b. Blending 40-50% polyamide, 30-40% polyphenylene ether, 5-15% graft-modified polyphenylene ether, 10-20% thermoplastic elastomer, 1-5% conductive carbon nanotubes, and 0.2-1% additive according to mass percentage to obtain a first mixture; c. extruding the first mixture in a temperature zone manner; d. Cooling and pelletizing the product extruded in step c to obtain an alloy masterbatch.

6. The process for preparing an alloy masterbatch capable of online spraying according to claim 5, characterized in that: In step c, the first mixture is fed into a twin-screw extruder, and the extrusion temperature is controlled to be 280-300°C.

7. The process for preparing an alloy masterbatch capable of online spraying according to claim 5, characterized in that: The preparation of graft-modified polyphenylene ether includes the following steps: adding dried polyphenylene ether, maleic anhydride and an initiator into a twin-screw extruder, melt-blending them in a temperature range of 180 to 260° C., completing the maleic anhydride grafting reaction, and obtaining the graft-modified polyphenylene ether, wherein the amount of maleic anhydride added is 1 to 5% of the mass of the polyphenylene ether, and the initiator is dicumyl peroxide, and the amount of dicumyl peroxide added is 0.2 to 1% of the mass of the polyphenylene ether.

8. The process for preparing an alloy masterbatch capable of online spraying according to claim 7, characterized in that: When melt blending in the temperature range of 180-260°C, the feeding zone: 180-200°C, the melting zone: 220-240°C, the reaction zone: 240-260°C, and the head zone: 230-250°C.

9. The process for preparing an alloy masterbatch capable of online spraying according to claim 8, characterized in that: During the grafting reaction, a vacuum exhaust port is provided in the middle of the extruder to remove unreacted maleic anhydride and its by-products.

10. The process for preparing an alloy masterbatch capable of online spraying according to claim 8, characterized in that: The screw speed of the twin-screw extruder is controlled within the range of 200 to 400 revolutions per minute, and the residence time of the material in the reaction zone is controlled within the range of 1 to 5 minutes.

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