Low-contact-pollution PBT (polybutylene terephthalate) flame-retardant reinforced material and preparation method thereof

Abstract

The invention discloses a low-contact-pollution PBT (polybutylene terephthalate) flame-retardant reinforced material and a preparation method thereof. The PBT flame-retardant reinforced material is prepared from the following components in percentage by weight: 40-45% of PBT resin, 28-33% of glass fiber, 15-18% of a flame retardant, 5-8% of an adhesive, 2-5% of nanoparticles, 1-5% of a flexibilizer, 1-3% of a nucleating agent, 1-2% of black masterbatch, 0.3-0.8% of a glass fiber surfactant, 0.2-0.5% of an antioxidant and 0.2-0.5% of a lubricant. The preparation method comprises the following steps: fully mixing the component materials according to the formula proportion, carrying out plasma corrosion, melting by a twin-screw extruder, and carrying out extrusion granulation. The invention relates to a formula and a processing method mainly aiming at the special requirement that plastic part foreign matters cause deadly defects of a relay. The invention has the main characteristics that: 1, the main formula meets the performance use requirements of the relay; and 2, foreign matters generated in the production process are reduced through a special formula and a treatment method, so that fatal defects of relay products are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular to a low contact point pollution PBT flame-retardant reinforced material and a preparation method thereof, and is mainly applied to the field of electronic and electrical appliances with metal contacts. BACKGROUND

[0002] Polybutylene terephthalate (PBT for short) is a white translucent to opaque, crystalline thermoplastic polyester. PBT has good mechanical properties, thermal stability and chemical stability, excellent electrical insulation, good impact resistance, good formability, low price and other characteristics, and is widely used in electronic appliances, automobiles, machinery and instruments, etc. It is one of the five engineering plastics.

[0003] Relay requires stable and reliable operation during operation. Therefore, important parts of the relay, such as the base, the shell, the wire rack, the push card and other components, require dimensional stability. These important components usually use PBT flame-retardant reinforced material, which is injection molded into a shape and used to assemble a relay product. During assembly, if the material itself falls off and the particle diameter of the debris is greater than 200 microns, these debris will adhere to the contacts of the relay, causing the relay to fail during operation, resulting in a non-working appliance. This is a fatal defect for the relay, so the PBT material needs to be treated to reduce the generation of debris after molding, thereby reducing the fatal defect of the relay and improving the reliability of the relay. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a low contact point pollution PBT flame-retardant reinforced material and a preparation method thereof, which can reduce the generation of plastic debris while maintaining the strength, elastic modulus, heat resistance temperature, dimensional stability and electrical properties of PBT material, thereby reducing the fatal defect of the relay and improving the reliability of the relay product.

[0005] The technical solution adopted by the present application to solve its technical problems is as follows: a low contact point pollution PBT flame-retardant reinforced material is composed of the following components by weight percentage: PBT resin 40-45%; Glass fiber 28-33%; Flame retardant 15-18%; Adhesive 5-8%; Nanoparticles 2-5%; Toughening agent 1-5%; Glass fiber surface activator 0.3-0.8%; Composite additive 3-6%.

[0006] The adhesive is a single-component epoxy resin.

[0007] The nanoparticles are a compound of nanosilica and nanomontmorillonite.

[0008] The PBT resin is polybutylene terephthalate, with a relative density of 1.30-1.34, a melting point of 220-235℃, and a melt index of 9-12g / 10min.

[0009] The glass fiber is an alkali-free glass fiber, and giant stone short glass fiber is used.

[0010] The flame retardant is a compound of antimony trioxide, brominated styrene, and decabromodiphenyl ethane.

[0011] The toughening agent is a compound of polyester elastomer and polypropylene.

[0012] The glass fiber surface activator is a C12-18 fatty alcohol polyoxyethylene ether compound.

[0013] The composite additive is a compound of nucleating agent, black mother, antioxidant, lubricant, etc.

[0014] A preparation method of a low-touch-point-contaminating PBT flame-retardant reinforcing material, comprising the following steps: A. Weigh the materials according to the proportion; B. Pour the prepared materials (except glass fiber) into a mixer to mix evenly to obtain a mixture, wherein the mixer speed is 150-200 revolutions per minute, and the time is 5-15 minutes; C. Put the mixed mixture into a plasma etching machine for 15 minutes.

[0015] D. Put the treated mixture into a double-screw extruder for extrusion and granulation, and add short glass fiber from the middle section of the double-screw extruder during production; wherein the processing conditions are as follows: double-screw extruder zone 1 220-225℃, zone 2 220-235℃, zone 3 220-240℃, zone 4 220-260℃, zone 5 220-260℃, zone 6 220-260℃, zone 7 220-250℃, zone 8 230-250℃, screw speed 350-450 revolutions per minute; E. Dust removal and packaging of the granulated materials.

[0016] This invention discloses a method for preparing a low-contact-pollution PBT flame-retardant reinforced material. It employs an adhesive to improve the bonding strength between materials in the formulation, and utilizes nanoparticles to effectively address the warpage problem of existing PBT modified materials while simultaneously improving the voltage resistance of PBT. Furthermore, it selects a nucleating agent to address the crystallinity of PBT during molding, increasing crystallinity and material regularity (i.e., orderly arrangement), thereby enhancing the material's voltage resistance and flexibility. Finally, it selects a glass fiber surfactant to improve the bonding strength between glass fiber and PBT resin and other additives, thus improving the material's mechanical properties. Finally, this invention utilizes a plasma etching process to increase the bonding strength of the various components in the material, reducing foreign matter detachment caused by insufficient bonding. This invention, by simultaneously adding adhesives, nanoparticles, nucleating agents, and glass fiber surfactants, and by adjusting the proportions of PBT resin, glass fiber, and other components, produces products with high strength, high flame retardancy, and minimal foreign matter shedding, thereby meeting the special requirements of stable performance and zero fatal defects in relay products.

[0017] The beneficial effects of this invention are: This invention, by simultaneously adding binders, nanoparticles, nucleating agents, and glass fiber surfactants to its composition, and through the combination of binders and nanoparticles, as well as the specific setting of the proportions of PBT resin, glass fiber, and other components such as binders, nanoparticles, nucleating agents, and glass fiber surfactants, employs a unique plasma etching process. This results in PBT modified materials possessing excellent mechanical and electrical properties, achieving the goal of minimizing foreign matter after PBT material molding. Consequently, it meets the assembly requirements of injection-molded electronic and electrical parts such as relays and capacitors, and effectively improves the safety and stability of relays and capacitors.

[0018] The present invention will be further described in detail below with reference to the embodiments; however, the low-contact-pollution PBT flame-retardant reinforced material and its preparation method of the present invention are not limited to the embodiments. Detailed Implementation

[0019] Example The present invention discloses a low-warpage, high-pressure-resistant PBT modified material, which is composed of the following components by weight percentage: PBT resin 40-45%; 28-33% glass fiber; Flame retardant 15-18%; Adhesive 5~8%; Nanoparticles 2-5%; Toughening agent 1~5%; Glass fiber surface activator 0.3~0.8%; Composite auxiliary agent 3~6%; Wherein, the PBT resin is polybutylene terephthalate, the relative density is 1.30~1.34, the melting point is 220~235℃, the melt index is 9~12g / 10min; the adhesive is a single-component epoxy resin; the nano-particle is a compound of nano-silicon dioxide and nano-montmorillonite; the glass fiber is alkali-free glass fiber, and giant stone short glass fiber is used; the flame retardant is a compound of antimony trioxide, brominated styrene and decabromodiphenyl ethane; the toughening agent is a compound of polyester elastomer and PP; the glass fiber surface activator is a C12-18 fatty alcohol polyoxyethylene ether compound; the composite auxiliary agent is a compound of nucleating agent, black mother, antioxidant and lubricant.

[0020] The application also provides a preparation method of the low-touch-point-pollution PBT flame-retardant reinforced material. A. The materials are weighed according to the proportion; B. The prepared materials (except glass fiber) are poured into a mixer to mix uniformly to obtain a mixture, wherein the stirring speed of the mixer is 150~200 revolutions per minute, and the time is 5~15 minutes; C. The uniformly mixed mixture is put into a plasma etching machine for 15 minutes.

[0021] D. The uniformly mixed mixture is put into a double-screw extruder for extrusion and granulation, and short glass fiber is added from the middle section of the double-screw extruder during the production process; wherein the processing conditions are as follows: the first zone of the double-screw extruder is 220-225℃, the second zone is 220-235℃, the third zone is 220-240℃, the fourth zone is 220-260℃, the fifth zone is 220-260℃, the sixth zone is 220-260℃, the seventh zone is 220-250℃, and the eighth zone is 230-250℃, and the screw rotation speed is 350~450 revolutions per minute; E. The granulated materials are dedusted and packaged.

[0022] The performance superiority of the application is further illustrated by specific examples. Example 1

[0023] The above materials of weight percentage PBT resin 42%, flame retardant 15%, adhesive 5%, nano-particle 2%, toughening agent 2%, glass fiber surface activator 0.5%, and composite aid 3.5% were poured into a blender and stirred for 10 minutes at a speed of 150 revolutions per minute. After 15 minutes of plasma etching, the mixture was automatically sucked into a double-screw extrusion granulator for granulation. During the granulation process, 30% short glass fibers were added from the middle section of the double-screw extruder. The processing conditions were as follows: double-screw extruder zone 1 225°C, zone 2 230°C, zone 3 240°C, zone 4 250°C, zone 5 260°C, zone 6 260°C, zone 7 250°C, and zone 8 250°C, with a screw speed of 400 revolutions per minute. Example 2

[0024] The above materials of weight percentage PBT resin 42%, flame retardant 15%, adhesive 5%, toughening agent 4%, glass fiber surface activator 0.5%, and composite aid 3.5% were poured into a blender and stirred for 10 minutes at a speed of 180 revolutions per minute. After mixing uniformly, the mixture was automatically sucked into a double-screw extrusion granulator for granulation after 15 minutes of plasma etching. During the granulation process, 30% short glass fibers were added from the middle section of the double-screw extruder. The processing conditions were as follows: double-screw extruder zone 1 225°C, zone 2 230°C, zone 3 240°C, zone 4 250°C, zone 5 260°C, zone 6 260°C, zone 7 250°C, and zone 8 250°C, with a screw speed of 400 revolutions per minute. Example 3

[0025] The above materials of weight percentage PBT resin 40%, flame retardant 15%, adhesive 7%, nano-particle 3%, toughening agent 2%, glass fiber surface activator 0.5%, and composite aid 3% were poured into a blender and stirred for 10 minutes at a speed of 200 revolutions per minute. After mixing uniformly, the mixture was automatically sucked into a double-screw extrusion granulator for granulation after 15 minutes of plasma etching. During the granulation process, 30% short glass fibers were added from the middle section of the double-screw extruder. The processing conditions were as follows: double-screw extruder zone 1 225°C, zone 2 230°C, zone 3 240°C, zone 4 250°C, zone 5 260°C, zone 6 260°C, zone 7 250°C, and zone 8 250°C, with a screw speed of 400 revolutions per minute.

[0026] Comparative Example 1 The above materials with weight percentage of PBT resin 44%, flame retardant 15%, toughening agent 3%, glass fiber surface activator 0.5%, composite auxiliary agent 2.5% are poured into a blender and stirred for 10 minutes, and then automatically sucked into a double-screw extrusion granulator after being mixed uniformly and subjected to plasma etching for 15 minutes. In the granulation process, 35% short glass fibers are added from the middle section of the double-screw extruder. The processing conditions are as follows: the temperature of the double-screw extruder is 225℃ in the first zone, 230℃ in the second zone, 240℃ in the third zone, 250℃ in the fourth zone, 260℃ in the fifth zone, 260℃ in the sixth zone, 250℃ in the seventh zone, and 250℃ in the eighth zone, and the screw rotation speed is 400 revolutions per minute.

[0027] Comparative Example 2 The above materials with weight percentage of PBT resin 46.5%, flame retardant 15%, adhesive 5%, toughening agent 3%, and composite auxiliary agent 0.5% are poured into a blender and stirred for 10 minutes, and then automatically sucked into a double-screw extrusion granulator after being mixed uniformly and subjected to plasma etching for 15 minutes. In the granulation process, 30% short glass fibers are added from the middle section of the double-screw extruder. The processing conditions are as follows: the temperature of the double-screw extruder is 225℃ in the first zone, 230℃ in the second zone, 240℃ in the third zone, 250℃ in the fourth zone, 260℃ in the fifth zone, 260℃ in the sixth zone, 250℃ in the seventh zone, and 250℃ in the eighth zone, and the screw rotation speed is 400 revolutions per minute.

[0028] Comparative Example 3 The above materials with weight percentage of PBT resin 45%, flame retardant 15%, nano-particles 4%, toughening agent 3%, glass fiber surface activator 0.5%, and composite auxiliary agent 2.5% are poured into a blender and stirred for 10 minutes, and then automatically sucked into a double-screw extrusion granulator after being mixed uniformly (without the plasma etching process). In the granulation process, 30% short glass fibers are added from the middle section of the double-screw extruder. The processing conditions are as follows: the temperature of the double-screw extruder is 225℃ in the first zone, 230℃ in the second zone, 240℃ in the third zone, 250℃ in the fourth zone, 260℃ in the fifth zone, 260℃ in the sixth zone, 250℃ in the seventh zone, and 250℃ in the eighth zone, and the screw rotation speed is 400 revolutions per minute.

[0029] Performance evaluation standards and performance indicators.

[0030] The materials prepared according to the above scheme are dried in a dehumidifying dryer at a temperature of 120-130℃ for 3-4 hours, and then a part of the materials is injection molded into standard test bars for testing, and another part of the materials is injection molded into relay parts. The injection molded parts of the present application are used as comparative test parts for the HF32F shell of Hongfa Science and Technology Co., Ltd.

[0031] The performance test adopts national standard test, and the part test mainly tests the amount of foreign matters (chips), the test method is filter paper analysis method, the specific method is that 10 plastic parts molded are taken into a glass cup with 200ml pure water, the container is put into an ultrasonic vibration machine, vibration is carried out for 15 minutes, the glass cup is taken out, the parts are taken out, the water in the cup is filtered through 0.8 micron filter paper, then the number of particles with diameter above 200 microns is counted through a microscope and automatic counting software, the particles below 200 microns have no influence on the relay, so they are not counted, and the amount of chips (foreign matters) after the material is formed is compared through this method.

[0032] The performances of examples 1-3 and comparative examples 1-3 are shown in table 1 and table 2 respectively.

[0033]

[0034] It can be seen from table 1 and table 2 that the amount of chips (foreign matters) is obviously increased without using adhesive, glass fiber surface activator and without carrying out plasma etching process, although the physical properties of the material have no great change, but the foreign matters are obviously increased, which has great influence on the fatal defect of the relay, therefore, the required PBT modified material can be obtained by adjusting the ratio of PBT resin, adhesive, glass fiber, nano particles and other substances and adopting plasma etching process.

[0035] The above examples are only used to further illustrate a low contact point pollution PBT flame-retardant reinforced material and its preparation method, but the present application is not limited to the examples, any simple modification, equivalent change and modification of the above examples according to the technical essence of the present application all fall into the protection scope of the technical scheme of the present application.

Claims

1. A low-contact-pollution PBT flame-retardant reinforced material, characterized in that: It consists of the following components by weight percentage: PBT resin 40-45%; 28-33% glass fiber; Flame retardant 15-18%; Adhesive 5~8%; Nanoparticles 2-5%; Toughening agent 1~5%; 0.3-0.8% glass fiber surfactant; Composite additives 3-6%.

2. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The adhesive is a single-component epoxy resin.

3. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The nanoparticles are a mixture of nano-silica and nano-montmorillonite.

4. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The PBT resin is polybutylene terephthalate, with a relative density of 1.30~1.34, a melting point of 220~235℃, and a melt index of 9~12 g / 10min.

5. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The glass fiber is alkali-free glass fiber, using Jushi short glass fiber.

6. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The flame retardant is a compound of antimony trioxide, styrene bromide, and decabromodiphenyl ethane.

7. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The toughening agent is a compound of polyester elastomer and polypropylene.

8. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The glass fiber surface activator is a C12-18 fatty alcohol polyoxyethylene compound.

9. The low-contact-pollution PBT flame-retardant reinforced material according to claim 1, characterized in that: The composite additive is a mixture of nucleating agent, black masterbatch, antioxidant, and lubricant.

10. A method for preparing a low-contact-fouling PBT flame-retardant reinforced material as described in any one of claims 1 to 12, characterized in that: Includes the following steps: A. Weigh the materials according to the proportions; B. Pour the prepared materials (except for glass fiber) into a mixer and mix them evenly to obtain a mixture. The mixer speed is 150~200 rpm and the time is 5~15 minutes. C. Place the well-mixed mixture into the plasma etching machine for 15 minutes; D. The treated mixture is fed into a twin-screw extruder for granulation. During the production process, short glass fibers are added from the middle section of the twin-screw extruder. The processing conditions are as follows: twin-screw extruder zone 1 220-225℃, zone 2 220-235℃, zone 3 220-240℃, zone 4 220-260℃, zone 5 220-260℃, zone 6 220-260℃, zone 7 220-250℃, zone 8 230-250℃, screw speed 350~450 rpm. E. Remove dust and package the granulated items.

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